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This news article talks about AI development and could be related closely to Geography and ICT combined.

AI is transforming conservation in Hong Kong. According to the article, startups like Robotics Cats are employing AI-powered systems to more effectively monitor habitats and estimate animal populations.

These systems use advanced surveillance technology and computer vision to detect wildfires, count birds, and track other species.

While there are challenges such as power supply issues in remote areas and accuracy limitations in certain environments, AI offers significant potential to enhance conservation efforts.

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AI can detect wildfires and monitor endangered birds, according to Hong Kong experts

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Technology could help conservation efforts by giving better population estimates, tracking habits of certain species.

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The Middle Ages span roughly 1,000 years, ending between 1400 and 1450. In Spain, however, 1492 is considered the end of their medieval period and the beginning of the modern era. The period was one of human expansion, centralization and great political upheaval and violence, resulting in the foundation of many modern European countries. It was also dominated by a surge in Christianity leading to the building of great cathedrals, clearing of large tracts of land by peasants, settling of new towns and villages, and building of great castles by local nobility.

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Crusades

Knights and kings were attacking the Holy Lands of the Middle East in the name of God and with the blessing of the Christian Church during this volatile period, which is sometimes called the Golden Age of Chivalry. The goal was to drive the Muslim tribes out of Palestine so that they could control the sacred lands of Jesus and the Bible.

The crusades happened in waves over the centuries as power shifted between the Christians and the Muslims, who fought back and reclaimed their territories. Each crusade generally lasted for a year or more before the area was secured and the queen could return home. By comparison, other expeditions into China or India could last two or three years.

By 1291, the Crusades were at an end and the crusading soldiers abandoned the area and returned home.

Military Orders

After conquering Jerusalem in 1099, an army was established to keep control of the city. This lead to the establishment of numerous military orders. These were a kind of association, group representation or affiliation to a particular leader, queen or cause; though all orders served the Christian (Catholic) Church in Rome.

Secularism

The Age of Chivalry ebbed after several Crusades, in which Jerusalem was won and lost, and its focus was shifted toward vain and selfish pursuits. This lead to the fighting of great wars-mostly between England and France - due to bickering among royal houses and noble families of different nations. As these high-ranking sides fought, the class divisions grew deeper and the poor were further exploited in order to support the rich. Nobles weren't the only ones shifting to less ethical behavior. Knights began fighting for the love of a woman or, if she was married, for another man's wife and all his possessions.

Courts

By mid-1300 new orders like the Order of the Golden Fleece were formed by royal courts. While knighthood was once a noble profession, now knight becoming less effective in the battle are more often were simple sporting entertainment for royal families.

Religion became less influential and even trivialized by some courts, 1337 saw the beginning of the The Hundred Years War between England and France.

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Medieval Era | Medieval Times Dinner & Tournament

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Knights and kings were attacking the Holy Lands of the Middle East in the name of God and with the blessing of the Christian Church during this volatile period, which is sometimes called the Golden Age of Chivalry. The goal was to drive the Muslim tribes out of Palestine so that they could control the sacred lands of Jesus and the Bible.

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Energy

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When you hear the words "clean energy," what comes to mind?

Most people immediately think of solar panels or wind turbines, but how many of you thought of nuclear energy?

Nuclear is often left out of the "clean energy" conversation despite it being the second largest source of low-carbon electricity in the world behind hydropower.

So, just how clean and sustainable is nuclear?

Try these quick facts for starters.

1. Nuclear energy protects air quality

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3 Reasons Why Nuclear is Clean and Sustainable

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Most people immediately think of solar panels or wind turbines as clean energy, but how many of you thought of nuclear energy?

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It's about different facts about natural resources such as oil coal and natural gas, using them are better than non natural resources but we are slowly running out of them.

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The Roman Republic describes the period in which the city-state of Rome existed as a republican government, from 509 B.C.E. to 27 B.C.E.

Etruscan kings who lived nearby in central Italy ruled Rome. These assemblies decided important matters for the city on behalf of its population.

The plebeians, who made up the majority of the soldiers in the Roman army, staged protests outside the city walls.

-National Geographic

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Image

Robert Harding Picture Library

The Roman Republic describes the period in which the city-state of Rome existed as a republican government, from 509 B.C.E. to 27 B.C.E. Rome's republican government is one of the earliest examples of representative democracy in the world.

Prior to the republic, Etruscan kings who lived nearby in central Italy ruled Rome. Once the last of these kings was overthrown in 509 B.C.E., Rome's wealthiest citizens established a republican government by creating various assemblies of Roman citizens. These assemblies decided important matters for the city on behalf of its population.

The early republican Senate clearly held a bias towards the interests of the wealthiest citizens. After all, only members of the patrician class could hold office. Therefore, the plebeians, who made up the majority of the soldiers in the Roman army, staged protests outside the city walls. This conflict led to the establishment of other legislative bodies, such as the Concilium Plebis or Council of Plebs, the Comitia Centuriata, and the Comita Tributa or the tribal assemblies. In the Council of Plebs and tribal assemblies, laws would be passed based on the discussion of important issues that took place in the Senate. There, senators recommended which policies to implement.

The Senate and assemblies worked together to appoint executive officials called magistrates, enacted laws, and sought to increase Rome's territorial holdings throughout the Italian peninsula. The Republic began to engage in wars with its neighboring rivals, slowly eliminating threats to its superiority in the Mediterranean. By the first century B.C.E., the Roman Republic stood alone as the dominant power in the Mediterranean region.

National Geographic Society

October 19, 2023

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The Roman Republic describes the period in which the city-state of Rome existed as a republican government (from 509 B.C.E. to 27 B.C.E.), one of the earliest examples of representative democracy in the world.

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This article is about the History ,Map, Population, City layout ,Climate ,Churches ,famous palaces and Fact about Rome.

💡🤔

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Rome, Italian Roma, historic city and capital of Roma provincia (province), of Lazio regione (region), and of the country of Italy. Rome is located in the central portion of the Italian peninsula, on the Tiber River about 15 miles (24 km) inland from the Tyrrhenian Sea. Once the capital of an ancient republic and empire whose armies and polity defined the Western world in antiquity and left seemingly indelible imprints thereafter, the spiritual and physical seat of the Roman Catholic Church, and the site of major pinnacles of artistic and intellectual achievement, Rome is the Eternal City, remaining today a political capital, a religious centre, and a memorial to the creative imagination of the past. Area city, 496 square miles (1,285 square km); province, 2,066 square miles (5,352 square km). Pop. (2011) city, 2,617,175; province, 3,997,465; (2022 est.) city, 2,761,632; province, 4,222,631.

Character of the city

For well over a millennium, Rome controlled the destiny of all civilization known to Europe, but then it fell into dissolution and disrepair. Physically mutilated, economically paralyzed, politically senile, and militarily impotent by the late Middle Ages, Rome nevertheless remained a world power-as an idea. The force of Rome the lawgiver, teacher, and builder continued to radiate throughout Europe. Although the situation of the popes from the 6th to the 15th century was often precarious, Rome knew glory as the fountainhead of Christianity and eventually won back its power and wealth and reestablished itself as a place of beauty, a source of learning, and a capital of the arts.

Rome's contemporary history reflects the long-standing tension between the spiritual power of the papacy and the political power of the Italian state capital. Rome was the last city-state to become part of a unified Italy, and it did so only under duress, after the invasion of Italian troops in 1870. The pope took refuge in the Vatican thereafter. Rome was made the capital of Italy (not without protests from Florence, which had been the capital since 1865), and the new state filled the city with ministries and barracks. Yet the Catholic church continued to reject Italian authority until a compromise was reached with Fascist dictator Benito Mussolini in 1929, when both Italy and Vatican City recognized the sovereignty of the other. Mussolini, meanwhile, created a cult of personality that challenged that of the pope himself, and his Fascist Party tried to re-create the glories of Rome's imperial past through a massive public works program.

Since Mussolini's fall and the traumas of World War II, when the city was occupied by Germans, politics have continued to dominate Rome's agenda-although regionalism began, in the 1980s, to devolve some political power away from the capital. Lagging behind Milan and Turin economically, Rome has maintained a peripheral place within the Italian and European economies. It also has been plagued with perennial housing shortages and traffic congestion. However, the late 20th and early 21st centuries brought increased efforts to resolve Rome's infrastructural problems and to foster a Roman cultural revival.

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Rome | Italy, History, Map, Population, Climate, & Facts

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Rome, historic city and the capital of Italy. It is in the central part of the Italian peninsula, on the Tiber River. Once capital of an ancient republic and empire and seat of the Roman Catholic Church, it became the site of major pinnacles of artistic and intellectual development and is called the Eternal City.

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This article is about HK drone that are used for protecting horseshoe crabs, this study is apart of ocean park.

It was told by ocean park on 20th June-international horseshoe crab day.

Over the years, Ocean park has been using the technology to look at the endangered species, they used drones to look over the horseshoe crabs and to see how they are doing.

Horseshoe crabs are becoming extinct because their blood has a component that can used to test for toxic materials and bacteria in vaccines, it can also be used for healthcare. In HK, there is less than 10,000 horseshoe crabs.

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Hong Kong researchers use drones, AI to protect horseshoe crabs

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Ocean Park Conservation Foundation said on-site testing began earlier this month in the New Territories.

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This article is about how Japan and other countries have been getting hotter and hotter due to a climate crisis

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Pedestrians use umbrellas to shelter from the midday sun as they cross a street in Tokyo earlier this year. Photo: AFP

Japan just had its hottest September in 125 years. So did a lot of places

This year is expected to be the hottest in human history as climate change accelerates, and Japan just had its hottest September since 1898

The 'extraordinary' average temperature jump of 2.66 degrees Celsius 'easily topped previous highs', an official from the Japanese weather agency said

Japan has seen its hottest September since records began 125 years ago, the weather agency said, in a year expected to be the warmest in human history.

The scorching September's average temperature was 2.66 degrees Celsius higher than usual, the Japan Meteorological Agency said on Monday.

This was "the highest figure since the start of statistics in 1898", the agency said in a statement.

Across Japan last month, 100 of 153 observation locations broke an average temperature record, including in Tokyo, with an all-time high of 26.7 degrees Celsius (80 degrees Fahrenheit), in Osaka with 27.9 degrees and in Nagoya with 27.3 degrees.

The average temperature jump of 2.66 degrees was "extraordinary" and "easily topped previous highs", weather agency official Masayuki Hirai said on Tuesday.

"If this is not an abnormally high temperature, I don't know what is," he said.

French weather authority Meteo-France said the September temperature average in the country will be around 21.5 degrees, between 3.5 degrees and 3.6 degrees above the 1991-2020 reference period.

Britain , too, has matched its record for the warmest September since records began in 1884.

The average global temperature in June, July and August was 16.77 degrees Celsius, surpassing the previous 2019 record, the European Union's Copernicus Climate Change Service said in a report.

In September, UN Secretary-General Antonio Guterres told world leaders the climate crisis had " opened the gates to hell ".

In his opening address at the Climate Ambition Summit, Guterres evoked this year's "horrendous heat" but stressed: "We can still limit the rise in global temperature to 1.5 degrees," referring to the target seen as needed to avoid long-term climate catastrophe.

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Last month was the hottest September in Japan for at least 125 years

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Japan recorded the highest average temperature for September since records began in 1898. This year is expected to be the hottest in human history as climate change accelerates.

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The Department of Humanities promotes research and training in liberal arts and social science disciplines such as, Humanities, History and Cultural Heritage, creating among them a connection based on these shared programmatic principles: the importance of documents and sources (written, visual, iconographic, monumental, material, landscape, oral, and media sources); the importance of historical and diachronic research, of philology and interdisciplinarity, as a methodological research and teaching approach to understand complex intellectual and cultural phenomena; the sensitivity towards an articulated reading of modernity and contemporaneity as well as towards the different forms of political, social and territorial organisation, through an innovative study of history and the past, as a way to amplify the perception and understanding of the present; the constant reference to the evolution and the multifaceted meaning of linguistic and literary tradition, to the huge literary, archaeological and artistic heritage, to territorial assets, and the deep cultural roots of our societies.

The Department achieves a coherent and harmonic synthesis of specialised knowledge and it is committed to translating the results of research into appropriate didactic forms, in the belief that the relationship between research and training is inseparable. In this perspective, the mission of the Department - which emphasises the importance of training future scholars, researchers, teachers and cultural experts in the various humanities disciplines - is to provide analytical, critical, communicative and educational skills through the development of specific basic and applied expertise, to encourage active participation in training processes, to develop creative and experimental abilities, with the aim of training highly specialised and informed citizens and to promote a culture of responsibility and social solidarity.

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The Department of Humanities promotes research and training in liberal arts and social science disciplines such as, Humanities, History and Cultural Heritage, creating among them a connection based on these shared programmatic principles: the importance of documents and sources (written, visual, ico

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Global warming is the long-term heating of Earth’s surface observed since the pre-industrial period (between 1850 and 1900) due to human activities, primarily fossil fuel burning, which increases heat-trapping greenhouse gas levels in Earth’s atmosphere. This term is not interchangeable with the term "climate change."

Climate change is a long-term change in the average weather patterns that have come to define Earth’s local, regional and global climates. These changes have a broad range of observed effects that are synonymous with the term.

NAFLA

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School is causing the students to have anxiety and depression, schools are also stopping students unlock their full potential. So school bad:)

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Inside Higher Ed | Higher Education News, Events and Jobs

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According to a survey of student counseling center workers, there are now wait lists for students seeking help.

The top two mental health issues are anxiety and depression, with over 4 in 10 students who seek help reporting the conditions.

Those of us working with students are unsurprised by these numbers. I first wrote about my experiences with student anxiety before I even had this space and since then, I've come to believe that we are in the midst of an anxiety "crisis" when it comes to students and school.

The obvious response to increased demand from students for mental health services is to ramp up the amount and availability of those services - and we should no doubt do this - but maybe at the same time we should ask a different question, "Why does exposure to school cause so much anxiety and depression?"

I have my personal theories, most significantly that students experience school not as a place to explore and fulfill their potentials, but a gauntlet to be run, where failure is severely punished, their futures of security and prosperity permanently foreclosed following even a slight bobble.

I work with many students who spend an inordinate amount of time fearing for their futures, despite the fact that many of them come from backgrounds of socioeconomic and demographic privilege.

Add in a climate of economic anxiety, the increasing costs of education (often in the form of loans that loom on the horizon), and a culture that encourages pursuit of "practical" studies that may be ill-suited to the spirit and desires of students, and you have an atmosphere that seems conducive to stress, depression, and anxiety.

What is the economic and human of moving students through a system that does so much damage?

How long will we treat the symptoms without examining the underlying causes?

--

Writing at Pacific Standard, Madeline Thomas asks, "Did we fail our kids by relying on prescription medication to treat ADHD?"

Thomas covers the struggles of a generation who has come of age taking prescription drugs like Ritalin and Adderall which were once, "considered a godsend when they first started being used to help hyperactive, unfocused kids succeed in school."

Now, Thomas finds adults who feel incapable of doing tasks as seemingly simple as grocery shopping without the aid of ADHD medication. They view themselves as addicts, terrified to navigate their professional lives without chemical aids.

They have experienced years of messed up sleep, reduced appetites, feelings that they're never quite themselves.

More distressingly, some report that medicating themselves to get through school prevented them from figuring out who they were really meant to be.

And yet, many also believe that without the medication, they wouldn't have been able to get through college.

I have heard these same sentiments from my students, that they need the help, otherwise they'd fail out. I ask them if they foresee a time when they won't need to take the medications.

"Retirement," one told me.

--

Reporting on a Hillary Clinton address to National Education Association teachers, Politico education reporter Caitlin Emma tweeted this remark from presumptive Democratic presidential nominee, Hillary Clinton.

Innocuous, right?

Maybe not.

--

Why do these stories converge for me?

With the epidemic of anxiety and depression, we have created a system that seems literally damaging to students' mental health. The very nature of what we ask them to do and how we ask them to do it seems to be harmful, and yet our response to this damage is to provide more resources to buff them up and get them back in the game.

For students diagnosed with ADHD, I believe we have pathologized differences. As schooling increasingly focused on paying "attention" and exhibiting compliance, those wired differently had to be "rewired," lest they "fall behind" their peers.

These two stories and Secretary Clinton's statement on tests share something in common, namely that school is a system where the student is fodder to feed the machine, rather than the product itself.

Rather than asking "What is good for students?" - "good" in every sense of the word - we instead orient policy and actions around abstractions like "success," or "college readiness" without examining the underlying costs of pursuing those abstractions.

And so we get a culture where seven-year-olds who don't get recess or art class and have difficulty paying attention for 45 minutes at a time become a problem in need of pharmaceutical intervention.

We get a culture where students see school not as a place to practice curiosity and grow socially, intellectually, and even spiritually, but a contest where the stakes are their future economic security and anxiety and depression are constant threats.

We get a culture where tests are not chances for students to test themselves and experience the fruits of their work and study, and are instead merely a chance to be judged by authorities who run the system.

These policies and perspectives are the result of prioritizing systems over people, of requiring conformity, and of valuing standardization over freedom and individuality.

They are anti-human, and it is not a mystery as to why they're failing.

I am not arguing that we should make school easier, that we need to ease up on the kids. My experience is that students enjoy challenges that are authentic and meaningful. They want to be given the chance to figure out who they are and what they can do. They crave it.

But that's not what we're doing. Succeeding in school, as schooling is currently designed, seems to actively work against students developing the habits, knowledge, and self-concept that will allow them to thrive as real-world adults.

How can we believe we're on the right track as students emerge depressed, anxious, medicated, and incapable of working without the oversight and approval of the authority figures?

We are screwing shit up. Each day we fail to confront what's happening and begin the long, hard process of shaping education around what we claim to actually value is a day wasted.

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Fortnite is back!

Multiplayer shooter game Fortnite is available again on iPhones in the European Union and worldwide on Google's Android devices after a gap of four years, following legal measures by the EU, developer Epic Games said on Friday.

Fortnite, created by Epic, a U.S.-based studio, and backed by China's Tencent, the world's largest game studio, launched in 2017 and its last-player-standing, "battle royale" format became an instant hit, drawing in millions of dedicated players.

But in August 2020, Apple and Alphabet's Google removed Fortnite from their app stores for violating their guidelines by launching a payment feature, prompting several lawsuits challenging their rules of charging up to 30% commissions on payments.

At the time of the ban, Epic had 116 million users just on Apple's platform.

The EU's Digital Markets Act (DMA) law is allowing Epic to launch its game store in the bloc, though Apple is still blocking users outside Europe from accessing Fortnite and its games store, the company said.

"We are really grateful to the European Commission for not only passing the DMA and enabling store competition, but also going in and robustly holding Apple and Google's feet to the fire to ensure that they can't just obstruct competition," Epic CEO Tim Sweeney told reporters.

"They were going to great efforts to slow us down, and tried to stop us several times, and the European Commission always stepped up and ensured that competitors were able to enter the market," he said.

The store is launching with Fortnite, Rocket League Sideswipe and the all-new Fall Guys for mobile, and Epic is working with other developers to launch their games and apps through its store.

Epic, which has 75 million monthly active users in its PC store, expects to add 100 million new mobile users by the end of the year.

The games would also be available through independent mobile stores such as AltStore.

However, the installation process is lengthy with a 15-step installation process on iOS devices, confusing device settings and scare screens, Epic said.

Apple said that to enable the new capabilities for developers in the EU, it worked to make them as easy as possible for users while also trying to protect their privacy and security.

"We probably lost over a billion dollars of revenue by losing access to the iOS customer base worldwide for four years, but what's the cost of freedom?," Sweeney said.

By Supantha Mukherjee

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STOCKHOLM (Reuters) - Multiplayer shooter game Fortnite is available again on iPhones in the European Union and worldwide on Google's Android devices after a gap of four years, following legal measures by the EU, developer Epic Games said on Friday.

Fortnite, created by Epic, a U.S.-based studio, and backed by China's Tencent, the world's largest game studio, launched in 2017 and its last-player-standing, "battle royale" format became an instant hit, drawing in millions of dedicated players.

But in August 2020, Apple and Alphabet's Google removed Fortnite from their app stores for violating their guidelines by launching a payment feature, prompting several lawsuits challenging their rules of charging up to 30% commissions on payments.

At the time of the ban, Epic had 116 million users just on Apple's platform.

The EU's Digital Markets Act (DMA) law is allowing Epic to launch its game store in the bloc, though Apple is still blocking users outside Europe from accessing Fortnite and its games store, the company said.

"We are really grateful to the European Commission for not only passing the DMA and enabling store competition, but also going in and robustly holding Apple and Google's feet to the fire to ensure that they can't just obstruct competition," Epic CEO Tim Sweeney told reporters.

"They were going to great efforts to slow us down, and tried to stop us several times, and the European Commission always stepped up and ensured that competitors were able to enter the market," he said.

The store is launching with Fortnite, Rocket League Sideswipe and the all-new Fall Guys for mobile, and Epic is working with other developers to launch their games and apps through its store.

Epic, which has 75 million monthly active users in its PC store, expects to add 100 million new mobile users by the end of the year.

The games would also be available through independent mobile stores such as AltStore.

However, the installation process is lengthy with a 15-step installation process on iOS devices, confusing device settings and scare screens, Epic said.

Apple said that to enable the new capabilities for developers in the EU, it worked to make them as easy as possible for users while also trying to protect their privacy and security.

"We probably lost over a billion dollars of revenue by losing access to the iOS customer base worldwide for four years, but what's the cost of freedom?," Sweeney said.

(Reporting by Supantha Mukherjee; Editing by David Holmes)

Copyright 2024 Thomson Reuters.

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Fortnite Returns on IPhones in EU, Globally on Android

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US News is a recognized leader in college, grad school, hospital, mutual fund, and car rankings. Track elected officials, research health conditions, and find news you can use in politics, business, health, and education.

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Siu Long 8NE (28) Cyclone Biparjoy storm

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Siu Long 8NE (28) Cyclone Biparjoy storm

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This article is about the tropical cyclone in Pakistan.

Related to geography history.

Cyclone Biparjoy was a storm that occurred in Pakistan, it happened during June 6 2023 to June 19 2023. It was a powerful tropical cyclone that had formed over the east-central Arabian Sea. Intensifying into a cyclonic storm. It caused a large flood was suppose but that night was a full moon which means the moon’s gravity pulled the flood creating tidal waves which made the flood higher.

81,000 people were evacuated from Pakistan southeast coast. At least 23 people were injured as well as 4,600 villages were affected by power outages in India. 12 people were confirmed to have been killed in India.

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Frontiers of the Roman Empire

The ‘Roman Limes’ represents the border line of the Roman Empire at its greatest extent in the 2nd century AD. It stretched over 5,000 km from the Atlantic coast of northern Britain, through Europe to the Black Sea, and from there to the Red Sea and across North Africa to the Atlantic coast. The remains of the Limes today consist of vestiges of built walls, ditches, forts, fortresses, watchtowers and civilian settlements. Certain elements of the line have been excavated, some reconstructed and a few destroyed.

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A landmark report on the impact of heavy weaponry on civilians and cultural heritage was released by Human Rights Watch (HRW) and the International Human Rights Clinic at Harvard Law School earlier this year. “Destroying Cultural Heritage: Explosive Weapons’ Effects in Armed Conflict and Measures to Strengthen Protection” shows how, as well as causing civilian casualties, this indirectly inflicts “psychosocial, economic, and other types of harm”.

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The Art Newspaper - International art news and events

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Why cultural destruction is such a dangerous military tactic

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A landmark report shows how attacks on heritage can cause “psychosocial, economic, and other types of harm”—but laws need to go further

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Loch Ness Monster Scottish Myth, known as Nessie. Some people said that the monster is friendly and others say it's violent. Some researchers said Nessie is Female and about 10 feet long. There are over 1,000 recorded sightings of the Loch Ness Monster. But still, no one successfully proved that Nessie existed.

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The “surgeon’s photograph” of 1934, now believed to have been a hoax[1]

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About their purpose and significance of medieval time castle.

These timber castles were quite cheap and very quick to build. However, the timber castles did have disadvantages. They were very vulnerable to attacks using fire and the wood would eventually start to rot. Due to these disadvantages, King William ordered that castles should be built in stone. Many of the original timber castles were replaced with stone castle

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What was their purpose and significance?

The castle as we know it today was introduced into England in 1066 during the Norman invasion led by William the Conqueror. After their victory at the Battle of Hastings, the Normans settled in England. They constructed castles all over the country in order to control their newly-won territory, and to pacify the Anglo-Saxon population. These early castles were mainly of motte and bailey type. The 'motte' was made up of a large mound of earth with a wooden tower on top, while the 'bailey' was a large ditch and bank enclosure which surrounded the motte.

These timber castles were quite cheap and very quick to build. However, the timber castles did have disadvantages. They were very vulnerable to attacks using fire and the wood would eventually start to rot. Due to these disadvantages, King William ordered that castles should be built in stone. Many of the original timber castles were replaced with stone castles.

Over time, stone castles were built in different architectural styles as builders experimented with castle-building techniques. In their infancy, castles were primarily military fortifications used to defend conquered territories from attack. The strategic location of the castle was paramount. However, once the Normans began to consolidate their control over England, castles began to take on a variety of different roles. Castles could serve as a centre for local government, administration and justice. They were also used by powerful lords to display their wealth and power through lavish architectural styles and decoration. Castles were not only built and used by the crown. In fact, the majority of castles were granted by the king to his loyal lords and nobles along with large areas of land. In return for these grants, the king expected his nobles to control and administer these lands on his behalf. The castle itself also represented a whole group of people who contributed to its function from constables, masons, blacksmiths and servants to name a few.

Use this lesson with original documents to find out more about the role of Framlingham, Portchester, Stokesay, Berwick, Alnwick, and Pevensey castles in medieval society.

Tasks

Teachers' notes

The purpose of this enquiry is to allow students to explore documents relating to the general function of castles. Did some people find them intimidating? Did a king view a castle in the same way as a peasant? Did a queen think about a castle in the same way as a builder?

The questions provided with each source act as prompts for students to answer the overarching question: What was the purpose and significance of castles?

The records used cover a range of material including royal grants, extracts from pipe rolls and the Calendar of Patent Rolls, royal orders, licences and pardons. We hope that these documents will offer students a chance to develop their powers of evaluation and analysis. All sources have been provided with a transcript and, as the language may prove challenging, we have also provided a simplified version with more difficult words defined within the text. Each source is captioned and dated to provide a sense of what the document is about. Alternatively, teachers may wish to use the sources to develop their own lesson in a different way or combine with other sources.

External links
Images of historic sites An overview of the 'Middle Ages'
Connections to Curriculum
Key Stage 4
AQA GCSE History
Britain: Power and the people: c1170 to the present day

OCR GCSE History
Castles Form and Function c1000-1750. Framlingham Castle was the first named site for the Historic Environment module, this is now Kenilworth Castle from 2019. The set site will be reviewed after three years and may be subject to change.

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Medieval castles - The National Archives

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The castle as we know it today was introduced into England in 1066 during the Norman invasion led by William the Conqueror. After their victory at the Battle of Hastings, the Normans settled in England. They constructed castles all over the country in order to control their newly-won territory, and to pacify the Anglo-Saxon population.

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Global warming of 1.1°C above pre-industrial levels has been caused by over a century of burning fossil fuels and unequal, unsustainable energy and land use. This has led to an increase in the frequency and intensity of extreme weather events, which have caused dangerous impacts on nature and people worldwide.

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This is about the humans and the wild animals coexisting in year 2070

As the human population grows, more than half of Earth’s land will experience an increasing overlap between humans and animals by 2070, according to a University of Michigan study.

Greater human-wildlife overlap could lead to more conflict between people and animals, say the U-M researchers. But understanding where the overlap is likely to occur—and which animals are likely to interact with humans in specific areas—will be crucial information for urban planners, conservationists and countries that have pledged international conservation commitments. Their findings are published in Science Advances.

“We found that the overlap between populations of humans and wildlife will increase across about 57% of the global lands, but it will decrease across only about 12% of the global lands. We also found that agricultural and forest areas will experience substantial increases of overlap in the future,” said Deqiang Ma, lead author of the study and a postdoctoral research fellow at the U-M Institute for Global Change Biology in the School for Environment and Sustainability.

The study showed that the human-wildlife overlap will be driven by human population growth rather than climate change. That is, the increase of people settling in previously undeveloped areas will drive the overlap rather than climate change causing animals to shift where they live.

“In many places around the world, more people will interact with wildlife in the coming decades and often those wildlife communities will comprise different kinds of animals than the ones that live there now,” said Neil Carter, principal investigator of the study and associate professor of environment and sustainability. “This means that all sorts of novel interactions, good and bad, between people and wildlife will emerge in the near future.”

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As the human population grows, more than half of Earth's land will experience an increasing overlap between humans and animals by 2070, according to a University of Michigan study.

Greater human-wildlife overlap could lead to more conflict between people and animals, say the U-M researchers. But understanding where the overlap is likely to occur-and which animals are likely to interact with humans in specific areas-will be crucial information for urban planners, conservationists and countries that have pledged international conservation commitments. Their findings are published in Science Advances.

"We found that the overlap between populations of humans and wildlife will increase across about 57% of the global lands, but it will decrease across only about 12% of the global lands. We also found that agricultural and forest areas will experience substantial increases of overlap in the future," said Deqiang Ma, lead author of the study and a postdoctoral research fellow at the U-M Institute for Global Change Biology in the School for Environment and Sustainability.

The study showed that the human-wildlife overlap will be driven by human population growth rather than climate change. That is, the increase of people settling in previously undeveloped areas will drive the overlap rather than climate change causing animals to shift where they live.

"In many places around the world, more people will interact with wildlife in the coming decades and often those wildlife communities will comprise different kinds of animals than the ones that live there now," said Neil Carter, principal investigator of the study and associate professor of environment and sustainability. "This means that all sorts of novel interactions, good and bad, between people and wildlife will emerge in the near future."

A human-driven issue

To calculate future human-wildlife overlap, the researchers created an index that combined estimates of where people are likely to populate land as well as the spatial distributions of 22,374 species of terrestrial amphibians, birds, mammals and reptiles.

They drew information about the spatial distribution of vertebrates from previously published data that forecasts where species will live based on their climatic niches. Their estimates of where people are likely to live were based on projections of economic development, global society and demographics.

"The index we created showed that the majority of global lands will experience increases in human-wildlife overlap, and this increasing overlap is the result of the expansion of human population much more so than changes in species distributions caused by climate change," Ma said.

Specifically, the researchers found that areas that currently have and are projected to have high human-wildlife overlap in 2015 and 2070 are concentrated in regions where human population density is already high, including China and India.

In addition to those places where overlap is already high, "another area of major concern are forests, particularly in forests in Africa and South America where we're seeing a large increase in the overlap in the future," Carter said. "The reason that is concerning is because those areas have very high biodiversity that would experience greater pressure in the future."

The researchers also found that median species richness-the variety of species in a given area-is projected to decrease across most forests in Africa and South America. In South America, mammal richness is projected to decline by 33%, amphibian richness by 45%, reptile richness by 40% and bird richness by 37%. In Africa, mammal richness is projected to decline by 21% and bird richness by 26%.

The need for biodiversity

Preserving biodiversity in these zones of overlap has real benefits, Carter said.

"There are cases of human-wildlife interactions that are both good and bad, but we anticipate that they're going to become more pronounced. For example, COVID19 was the result of human contact with wild animals, and there is concern that new diseases will emerge from greater encounters between people and certain wildlife species," he said. "But you also have species that provide important benefits to people, like reducing the abundances of pests."

For example, part of Ma's data analysis looked at birds that eat insects in agricultural areas and examined where those birds will go under climate change. He found that more than two-thirds of the croplands that will likely experience an increase of human-wildlife overlap by 2070 will see a decline in bird species that can help reduce crop pests.

"What we're doing is finding those areas and saying, if you have cropland or pastures here, are you going to have species move into those areas or species moving away from those areas," Carter said. "Are those new croplands or pastures going to be an additional threat to the species or could there be ecosystem services harnessed for free?"

Scavengers such as vultures and hyenas also play a critical role by cleaning waste from urban areas and other landscapes, Carter said. By clearing waste, scavengers can reduce the prevalence of some human diseases such as rabies, anthrax and bovine tuberculosis.

"Hyenas and other species that are vilified or persecuted because they are scavengers provide a lot of disease reduction benefits," Carter said. "On one hand, they're viewed as a threat, but on the other hand, they're providing free health benefits."

Equitable conservation

Future conservation strategies will have to evolve, especially in regions that previously haven't seen much human settlement, according to the researchers. In the past, a core conservation strategy was to establish protected areas where human access is restricted. This is becoming harder to implement because there are fewer such places.

"There's also a significant environmental justice argument around the validity of telling communities that may have lived in a certain area for generations that they have to move," Carter said. "Our study suggests that with more areas of the world expected to be shared both by people and wildlife, conservation planning will have to get more creative and inclusive."

Conservationists will need to engage local communities to build interest in helping improve the conservation process. This process may include establishing habitat corridors to connect existing protected areas to potentially new areas or to create temporary protected areas during critical periods for wildlife, like breeding periods, as well as other conservation innovations.

"We care a lot about which areas can support populations of endangered species, like tigers, and how human communities interact with these species," Carter said. "In some places it's going to be really hard to do everything at once: to grow crops and have urban areas and protect these species and their habitats. But if we can start planning now, we have a lot of tools to help us promote sustainable coexistence."

Co-authors of the study include Briana Abrahms of the University of Washington, U-M ecologist Jacob Allgeier, Tim Newbold of the University College London and U-M evolutionary ecologist Brian Weeks.

The study, " Global expansion of human-wildlife overlap in the 21st century " (DOI: 10.1126/sciadv.adp7706)

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Human-wildlife overlap expected to increase across more than half of land on Earth by 2070

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As the human population grows, more than half of Earth's land will experience an increasing overlap between humans and animals by 2070, according to a University of Michigan study.

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A study, which was published in ‘Global Change Biology’, indicated that garbage and foreign animals from countries in the southern hemisphere are significantly affecting wildlife in the Antarctic region through a simulation. Lethal diseases can also be brought to Antarctica, which may cause disastrous consequences to the ecosystem. Foreign species being brought to the south might not be able to survive under the treacherous climate.

This article is related to geography.

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Antarctic ecosystems could be disrupted by animals, diseases and rubbish floating from Africa and Australia as rising temperatures melt sea ice buffers, new research suggests.

The study, published in the journal Global Change Biology, used a simulation of ocean currents to track the paths of virtual objects released from different locations.

Simulations showed objects from Australia, South Africa, South America and New Zealand reached Antarctica every year, while objects from islands in the Southern Ocean made landfall even more frequently.

"Things can drift to Antarctica from much further north than we previously thought," said Dr Hannah Dawson, the study's lead author.

While foreign species have not yet settled on Antarctic coasts, the study suggests that waves and currents have carried objects from around the southern hemisphere to Antarctica's coasts for thousands of years.

"If things are getting there frequently, it must be the cold waters and the icy conditions that are preventing them from actually establishing," Dawson said. "But these conditions are changing."

Plants and animals that have previously drifted toward Antarctica may have been destroyed by the floating sea ice that constantly crushes and scrapes against the coastline. Alternatively, they may have been unable to survive the cold.

Why thousands of emperor penguin chicks in Antarctica died in the 2022 breeding season - video

But as temperatures rise and sea ice melts, foreign species would have a greater chance of colonising the coastline. Antarctic sea ice has fallen to alarming lows for three years in a row.

Rising plastic pollution also means there is more debris the animals can float on to travel south, after the number of plastic particles afloat in the world's oceans was found to have surpassed 170tn in 2023.

Floating plastic could bring ants and diseases such as bird flu, while drifting kelp and seaweeds could transport crabs, sea stars and slugs, according to Ceridwen Fraser, the study's co-author and a biogeographer at the University of Otago.

"It's really worrying for the species of Antarctica," she said. "If foreign arrivals travelled and successfully settled the warming Antarctic coast, they would have a survival advantage over native species, which tend to be slower to grow."

Dawson said: "They might out-compete local species and those local species would probably then have nowhere else to go."

The study also found the Antarctic peninsula would be most vulnerable to colonisation, with the vast majority of simulated items making landfall at the continent's northernmost point.

By some climate change models, the peninsula would be the first part of the continent to rise to temperatures that would enable overseas life to settle, according to Andy Hogg, director of the research facility ACCESS-NRI.

Hogg said the paper's advanced modelling showed scientists needed to investigate which organisms from other continents could survive in Antarctic conditions and survive on the coastline.

Jordan Pitt, an ocean mathematician at the University of Sydney, said the peninsula's west coast was already routinely free of sea ice in summer and would be a key spot for researchers to watch out for species arrivals.

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Rubbish and disease could disrupt Antarctic ecosystems as ice buffers melt, study finds

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Simulated study shows southern ecosystems could be compromised by objects from South Africa, South America, New Zealand and Australia as global heating continues

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this article is about a power typhoon on Friday, as Typhoon Ampil approaches the east coast near the capital.

The storm, located 121 nautical miles southeast of Yokosuka, Greater Tokyo, has intensified to the equivalent strength of a Category 4 hurricane, bringing winds of up to 212 kilometers per hour (131 mph) as it moves north at 18 kph (11 mph), according to the Joint Typhoon Warning Center (JTWC).

Ampil has rapidly intensified over the past two days, partly because it moved over very warm water – meaning more moisture in the air to fuel the typhoon. It could strengthen further in the next 12 hours, with the storm reaching peak intensity as it passes by Japan.

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Jessie Yeung, Taylor Ward, Robert Shackelford

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Japan braces as powerful Typhoon Ampil strengthens near Tokyo | CNN

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Hundreds of thousands of people are being advised to evacuate in parts of Japan, with some homes losing power on Friday, as Typhoon Ampil approaches the east coast near the capital.

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Erica Rhinehart who was walking her cat in her neighbourhood until her neighbour told her about a female mountain lion that was in her yard trapped under furniture ,after Colorado Parks and Wildlife staff euthanize the mountain lion and doing some tissue test they found out it had a deadly disease that has also been found in European domestic cats.

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A deadly disease that affects cats big and small found in U.S.

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The virus inflamed a cougar’s brain and tissue in Colorado, though it’s unclear how long the disease has been on the continent or how prevalent it is.

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This article about climate change ,Human activities are causing greenhouse gasses warming the world faster.The average temperature of the Earth’s surface is now about 1.2°C  Many people think climate change mainly means warmer temperatures. But it isn't The consequences of climate change now are rising sea levels, flooding, melting polar ice….

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Forest loss intensifies climate change by increasing temperatures and cloud level, which leads to decrease of water.

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This article is about the decrease of rain and water in Africa due to forest loss intensifying climate change, which increases temperatures and cloud level.

Researchers have reported that deforestation during the last two decades increased a higher warming temperature and cloud level rise than that caused by climate change, which threatens biodiversity and water supply in African montane forests.

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Montane forests are often cloudy, wet, cold, and occur on isolated mountains in Africa. They are rich in biodiversity and act as water towers by trapping water from fog and clouds, providing high quality fresh water for millions of people in the lowlands of Africa.

In the last two decades, as much as 18 % of Africa's montane forests were lost due to deforestation, which resulted in a warming and cloud level rise two times higher than that caused by climate change. Research resulted that air temperature has increased by 1,4 centigrades, while cloud level has risen by 230 meters during the last 20 years.

"It has strong consequences to the water resources and biodiversity," comments Prof. Dirk Zeuss from the University of Marburg.

The study is published in Nature Communications.
Cloud level rise decreases water harvesting
The rise of the cloud level decreases water harvesting, as when the cloud touches the forest canopy, the fog (water) is deposited on the plant and land surfaces. If the cloud base is higher, this phenomenon does not take place, clarifies Prof. Petri Pellikka, the director of Taita Research Station.

The phenomenon also requires that mountain tops are forested as it increases the surface area of land cover, and in the forest, water is stored in the trees and soil better than on open lands.

The study sites were located in the highlands of Kenya, Tanzania, Ethiopia and South Africa. The study was one of the outputs of Taita Research Station, which the University of Helsinki has maintained in southern Kenya since 2009. The contribution from the University of Helsinki for the study was from the Earth Change Observation Laboratory at the Department of Geosciences and Geography.

"In our studies in Taita Hills, it was measured that annually in forested mountain tops, 20 % more water was landing on the ground compared to open areas. This is due to fog deposited on the trees, which drips on the ground as droplets. This is additional to the rainfall. If the clouds remain higher and do not touch the forests, this phenomenon does not take place anymore," says Pellikka.

Many small forested mountain tops remain in the Taita Hills. Kenya's most important water towers include Mt. Kenya, the Mau Forest, the Aberdare Mountains, Mt. Elgon, the Cherangani Hills, and Mt. Kilimanjaro. Although Mt. Kilimanjaro is located in Tanzania, it also provides water to the Kenyan side.

"Around the highest mountain in Africa, Kilimanjaro in Tanzania, 50 % of the forest is lost since 1880," comments Dr. Andreas Hemp from the University of Bayreuth. He has been carrying out research in Kilimanjaro for 30 years.
Negative relationship between temperature and elevation
The study also found that due to the negative relationship between temperature and elevation, the impacts of warming due to deforestation can decrease with increasing elevation. Nonetheless, large-scale deforestation (i.e., tree cover loss exceeding 70 % at a 1 km x 1 km area) can offset the cooling effect of elevation and comparable warming can be induced at higher elevations in African montane forests.

"The results call for urgent action as montane deforestation induced by cropland expansion and logging poses serious threats to biodiversity and ecosystem services, such as water supply in Africa," says Temesgen Abera, a visiting scholar from the University of Helsinki and a postdoctoral researcher in Philipps University of Marburg (Germany), funded by the Alexander von Humboldt foundation.

The study used a data-driven approach based on satellite observations, reanalysis data, as well as ensemble learning, empirical methods, and independent in-situ temperature and cloud base height measurements for validation.

The research group included scientists from University of Helsinki, University of Marburg and University of Bayreuth in Germany, Finnish Meteorological Institute, Addis Abeba University in Ethiopia, and North-West University in South Africa. The research of was of ESSA project (Earth observation and environmental sensing for climate-smart sustainable agropastoral ecosystem transformation in East Africa) funded by the European Commission.

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drought; nature; ecology research; biology; drought research; water; forest; environmental issues

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Forest loss intensifies climate change by increasing temperatures and cloud level, which leads to decrease of water

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Researchers report that deforestation during the last two decades induced a higher warming and cloud level rise than that caused by climate change, which threatens biodiversity and water supply in African montane forests.

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Archaeologists in Spain have found a lost Roman city in the Spanish regions of Arcos de la Frontera, Bornos Villamartin and Puerto Serrano and were originally linked by trade and communication routes along the Guadalete river.

As part of the ambitious project, the team employed cutting-edge technology, including ground-penetrating radar to detect structures buried beneath the surface. The advanced method allowed researchers to identify wall structures used by the Romans that were not visible to the naked eye.

The Roman settlement of the Guadalete River is believed to date back to the Roman conquest of Spain in 264BC, but researchers are still working to confirm the exact dates of the newly discovered structures.Professor Lara said the data uncovered so far represents a meaningful foundation for their ongoing research.

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Global warming directly affects human mortality. Governments, medical institutions and other bodies require accurate models on health-related matters in order to better organize their activities. Climate change has measurable impacts on society, including on human mortality. However, current models to assess the health impacts of climate change do not account for every environmental parameter, especially humidity, which could influence heat stress perceived by the human body, leaving room for improvement. Researchers have now incorporated humidity data from hundreds of cities into so-called heat stress indicators (HSIs) and assessed their performances in predicting heat-related deaths.

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Incorporating humidity improves estimations of climate impacts on health

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Governments, medical institutions and other bodies require accurate models on health-related matters in order to better organize their activities. Climate change has measurable impacts on society, including on human mortality. However, current models to assess the health impacts of climate change do not account for every environmental parameter, especially humidity, which could influence heat stress perceived by the human body, leaving room for improvement. Researchers have now incorporated humidity data from hundreds of cities into so-called heat stress indicators (HSIs) and assessed their performances in predicting heat-related deaths.

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It is about how Roma empire collasped and still kept their architecture

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Rome’s Transition from Republic to Empire

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Rome transitioned from a republic to an empire after power shifted away from a representative democracy to a centralized imperial authority, with the emperor holding the most power.

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Following a major earthquake, a 15-meter tsunami disabled the power supply and cooling of three Fukushima Daiichi reactors, causing a nuclear accident beginning on 11 March 2011, all three cores largely melted in the first three days.

The accident was rated level 7 on the International Nuclear and Radiological Event Scale, due to high radioactive releases over days 4 to 6.

All four Fukushima Daiichi reactors were written off due to damage in the accident .

After two weeks, the three reactors were stable with water addition by july.

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Following a major earthquake, a 15-metre tsunami disabled the power supply and cooling of three Fukushima Daiichi reactors, causing a nuclear accident beginning on 11 March 2011. All three cores largely melted in the first three days.

The accident was rated level 7 on the International Nuclear and Radiological Event Scale, due to high radioactive releases over days 4 to 6, eventually a total of some 940 PBq (I-131 eq).

All four Fukushima Daiichi reactors were written off due to damage in the accident - 2719 MWe net.

After two weeks, the three reactors (units 1-3) were stable with water addition and by July they were being cooled with recycled water from the new treatment plant. Official 'cold shutdown condition' was announced in mid-December.

Apart from cooling, the basic ongoing task was to prevent release of radioactive materials, particularly in contaminated water leaked from the three units. This task became newsworthy in August 2013.

There have been no deaths or cases of radiation sickness from the nuclear accident, but over 100,000 people were evacuated from their homes as a preventative measure. Government nervousness has delayed the return of many.

Official figures show that there have been 2313 disaster-related deaths among evacuees from Fukushima prefecture. Disaster-related deaths are in addition to the about 19,500 that were killed by the earthquake or tsunami.

The Great East Japan Earthquake of magnitude 9.0 at 2.46 pm on Friday 11 March 2011 did considerable damage in the region, and the large tsunami it created caused very much more. The earthquake was centred 130 km offshore the city of Sendai in Miyagi prefecture on the eastern coast of Honshu Island (the main part of Japan), and was a rare and complex double quake giving a severe duration of about 3 minutes. An area of the seafloor extending 650 km north-south moved typically 10-20 metres horizontally. Japan moved a few metres east and the local coastline subsided half a metre. The tsunami inundated about 560 km ² and resulted in a human death toll of about 19,500 and much damage to coastal ports and towns, with over a million buildings destroyed or partly collapsed.

Eleven reactors at four nuclear power plants in the region were operating at the time and all shut down automatically when the earthquake hit. Subsequent inspection showed no significant damage to any from the earthquake. The operating units which shut down were Tokyo Electric Power Company's (Tepco's) Fukushima Daiichi 1, 2, 3, and Fukushima Daini 1, 2, 3, 4, Tohoku's Onagawa 1, 2, 3, and Japco's Tokai, total 9377 MWe net. Fukushima Daiichi units 4, 5&6 were not operating at the time, but were affected. The main problem initially centred on Fukushima Daiichi 1-3. Unit 4 became a problem on day five.

The reactors proved robust seismically, but vulnerable to the tsunami. Power, from grid or backup generators, was available to run the residual heat removal (RHR) system cooling pumps at eight of the eleven units, and despite some problems they achieved 'cold shutdown' within about four days. The other three, at Fukushima Daiichi, lost power at 3.42 pm, almost an hour after the earthquake, when the entire site was flooded by the 15-metre tsunami. This disabled 12 of 13 backup generators onsite and also the heat exchangers for dumping reactor waste heat and decay heat to the sea. The three units lost the ability to maintain proper reactor cooling and water circulation functions. Electrical switchgear was also disabled. Thereafter, many weeks of focused work centred on restoring heat removal from the reactors and coping with overheated spent fuel ponds. This was undertaken by hundreds of Tepco employees as well as some contractors, supported by firefighting and military personnel. Some of the Tepco staff had lost homes, and even families, in the tsunami, and were initially living in temporary accommodation under great difficulty and privation, with some personal risk. A hardened onsite emergency response centre was unable to be used in grappling with the situation, due to radioactive contamination.

Three Tepco employees at the Daiichi and Daini plants were killed directly by the earthquake and tsunami, but there have been no fatalities from the nuclear accident.

Among hundreds of aftershocks, an earthquake with magnitude 7.1, closer to Fukushima than the 11 March one, was experienced on 7 April, but without further damage to the plant. On 11 April a magnitude 7.1 earthquake and on 12 April a magnitude 6.3 earthquake, both with the epicentre at Fukushima-Hamadori, caused no further problems.

The two Fukushima plants and their siting

The Daiichi (first) and Daini (second) Fukushima plants are sited about 11 km apart on the coast, Daini to the south.

The recorded seismic data for both plants - some 180 km from the epicentre - shows that 550 Gal (0.56 g) was the maximum ground acceleration for Daiichi, and 254 Gal was maximum for Daini. Daiichi units 2, 3 and 5 exceeded their maximum response acceleration design basis in an east-west direction by about 20%. The recording was over 130-150 seconds. (All nuclear plants in Japan are built on rock - ground acceleration was around 2000 Gal a few kilometres north, on sediments).

The original design basis tsunami height was 3.1 m for Daiichi based on assessment of the 1960 Chile tsunami and so the plant had been built about 10 metres above sea level with the seawater pumps 4 m above sea level. The Daini plant was built 13 metres above sea level. In 2002 the design basis was revised to 5.7 metres above, and the seawater pumps were sealed. In the event, tsunami heights coming ashore were about 15 metres, and the Daiichi turbine halls were under some 5 metres of seawater until levels subsided. Daini was less affected. The maximum amplitude of this tsunami was 23 metres at point of origin, about 180 km from Fukushima.

In the last century there have been eight tsunamis in the region with maximum amplitudes at origin above 10 metres (some much more), these having arisen from earthquakes of magnitude 7.7 to 8.4, on average one every 12 years. Those in 1983 and in 1993 were the most recent affecting Japan, with maximum heights at origin of 14.5 metres and 31 metres respectively, both induced by magnitude 7.7 earthquakes. The June 1896 earthquake of estimated magnitude 8.3 produced a tsunami with run-up height of 38 metres in Tohoku region, killing more than 27,000 people.

The tsunami countermeasures taken when Fukushima Daiichi was designed and sited in the 1960s were considered acceptable in relation to the scientific knowledge then, with low recorded run-up heights for that particular coastline. But some 18 years before the 2011 disaster, new scientific knowledge had emerged about the likelihood of a large earthquake and resulting major tsunami of some 15.7 metres at the Daiichi site. However, this had not yet led to any major action by either the plant operator, Tepco, or government regulators, notably the Nuclear & Industrial Safety Agency (NISA). Discussion was ongoing, but action minimal. The tsunami countermeasures could also have been reviewed in accordance with International Atomic Energy Agency (IAEA) guidelines which required taking into account high tsunami levels, but NISA continued to allow the Fukushima plant to operate without sufficient countermeasures such as moving the backup generators up the hill, sealing the lower part of the buildings, and having some back-up for seawater pumps, despite clear warnings.

A report from the Japanese government's Earthquake Research Committee on earthquakes and tsunamis off the Pacific coastline of northeastern Japan in February 2011 was due for release in April, and might finally have brought about changes. The document includes analysis of a magnitude 8.3 earthquake that is known to have struck the region more than 1140 years ago, triggering enormous tsunamis that flooded vast areas of Miyagi and Fukushima prefectures. The report concludes that the region should be alerted of the risk of a similar disaster striking again. The 11 March earthquake measured magnitude 9.0 and involved substantial shifting of multiple sections of seabed over a source area of 200 x 400 km. Tsunami waves devastated wide areas of Miyagi, Iwate and Fukushima prefectures.
(See also background on Earthquakes and Seismic Protection for Nuclear Power Plants in Japan)
Events at Fukushima Daiichi 1-3 & 4

It appears that no serious damage was done to the reactors by the earthquake, and the operating units 1-3 were automatically shut down in response to it, as designed. At the same time all six external power supply sources were lost due to earthquake damage, so the emergency diesel generators located in the basements of the turbine buildings started up. Initially cooling would have been maintained through the main steam circuit bypassing the turbine and going through the condensers.

Then 41 minutes later, at 3:42 pm, the first tsunami wave hit, followed by a second 8 minutes later. These submerged and damaged the seawater pumps for both the main condenser circuits and the auxiliary cooling circuits, notably the residual heat removal (RHR) cooling system. They also drowned the diesel generators and inundated the electrical switchgear and batteries, all located in the basements of the turbine buildings (the one surviving air-cooled generator was serving units 5&6). So there was a station blackout, and the reactors were isolated from their ultimate heat sink. The tsunamis also damaged and obstructed roads, making outside access difficult.

All this put reactors 1-3 in a dire situation and led the authorities to order, and subsequently extend, an evacuation while engineers worked to restore power and cooling. The 125-volt DC back-up batteries for units 1&2 were flooded and failed, leaving them without instrumentation, control or lighting. Unit 3 had battery power for about 30 hours.

At 7:03 pm Friday 11 March a nuclear emergency was declared, and at 8:50pm the Fukushima prefecture issued an evacuation order for people within 2 km of the plant. At 9:23 pm the prime minister extended this to 3 km, and at 5:44 am on 12 March he extended it to 10 km. He visited the plant soon after. Later on Saturday 12 March he extended the evacuation zone to 20 km.

Inside the Fukushima Daiichi reactors

The Fukushima Daiichi reactors were GE boiling water reactors (BWRs) of an early (1960s) design supplied by GE, Toshiba and Hitachi, with what is known as a Mark I containment. Reactors 1-3 came into commercial operation 1971-75. Reactor capacity was 460 MWe for unit 1, 784 MWe for units 2-5, and 1100 MWe for unit 6.

When the power failed at 3:42 pm, about one hour after shutdown of the fission reactions, the reactor cores would still have been producing about 1.5% of their nominal thermal power, from fission product decay - about 22 MW in unit 1 and 33 MW in units 2&3. Without heat removal by circulation to an outside heat exchanger, this produced a lot of steam in the reactor pressure vessels (RPVs) housing the cores, and this was released into the dry primary containment (PCV) through safety valves. Later this was accompanied by hydrogen, produced by the interaction of the fuel's very hot zirconium cladding with steam after the water level dropped.

As pressure started to rise here, the steam was directed into the suppression chamber/wetwell under the reactor, within the containment, but the internal temperature and pressure nevertheless rose quite rapidly. Water injection commenced, using the various systems provide for this and finally the emergency core cooling system (ECCS). These systems progressively failed over three days, so from early Saturday water injection to the RPV was with fire pumps, but this required the internal pressures to be relieved initially by venting into the suppression chamber/wetwell. Seawater injection into unit 1 began at 7:00 pm on Saturday 12, into unit 3 on Sunday 13 and unit 2 on Monday 14. Tepco management ignored an instruction from the prime minister to cease the seawater injection into unit 1, and this instruction was withdrawn shortly afterwards.

Inside unit 1, it is understood that the water level dropped to the top of the fuel about three hours after the scram (about 6:00 pm) and the bottom of the fuel 1.5 hours later (7:30 pm). The temperature of the exposed fuel rose to some 2800°C so that the central part started to melt after a few hours and by 16 hours after the scram (7:00 am Saturday) most of it had fallen into the water at the bottom of the RPV. After that, RPV temperatures decreased steadily.

As pressure rose, attempts were made to vent the containment, and when external power and compressed air sources were harnessed this was successful, by about 2:30 pm Saturday, though some manual venting was apparently achieved at about 10:17 am. The venting was designed to be through an external stack, but in the absence of power much of it apparently backflowed to the service floor at the top of the reactor building, representing a serious failure of this system (though another possibility is leakage from the drywell). The vented steam, noble gases and aerosols were accompanied by hydrogen. At 3:36 pm on Saturday 12, there was a hydrogen explosion on the service floor of the building above unit 1 reactor containment, blowing off the roof and cladding on the top part of the building, after the hydrogen mixed with air and ignited. (Oxidation of the zirconium cladding at high temperatures in the presence of steam produces hydrogen exothermically, with this exacerbating the fuel decay heat problem.)

In unit 1 most of the core - as corium, composed of melted fuel and control rods - was assumed to be in the bottom of the RPV, but later it appeared that it had mostly gone through the bottom of the RPV and eroded about 65 cm into the drywell concrete below (which is 2.6 m thick). This reduced the intensity of the heat and enabled the mass to solidify.

Much of the fuel in units 2&3 also apparently melted to some degree, but to a lesser extent than in unit 1, and a day or two later. In mid-May 2011 the unit 1 core would still have been producing 1.8 MW of heat, and units 2&3 about 3.0 MW each.

In mid-2013 the Nuclear Regulation Authority (NRA) confirmed that the earthquake itself had caused no damage to unit 1.

In unit 2, water injection using the steam-driven back-up water injection system failed on Monday 14, and it was about six hours before a fire pump started injecting seawater into the RPV. Before the fire pump could be used RPV pressure had to be relieved via the wetwell, which required power and nitrogen, hence the delay. Meanwhile the reactor water level dropped rapidly after backup cooling was lost, so that core damage started about 8 pm, and it is now understood that much of the fuel then melted and probably fell into the water at the bottom of the RPV about 100 hours after the scram. Pressure was vented on Sunday 13 and again on Tuesday 15, and meanwhile the blowout panel near the top of the building was opened to avoid a repetition of the hydrogen explosion at unit 1. Early on Tuesday 15, the pressure suppression chamber under the actual reactor seemed to rupture, possibly due to a hydrogen explosion there, and the drywell containment pressure inside dropped. However, subsequent inspection of the suppression chamber did not support the rupture interpretation. Later analysis suggested that a leak of the primary containment developed on Tuesday 15. Most of the radioactive releases from the site appeared to come from unit 2.

In unit 3, the main backup water injection system failed at about 11:00 am on Saturday 12, and early on Sunday 13 water injection using the high pressure system failedalsoand water levels dropped dramatically. RPV pressure was reduced by venting steam into the wetwell, allowing injection of seawater using a fire pump from just before noon. Early on Sunday venting the suppression chamber and containment was successfully undertaken. It is now understood that core damage started about 5:30 am and much or all of the fuel melted on the morning of Sunday 13 and fell into the bottom of the RPV, with some probably going through the bottom of the reactor pressure vessel and onto the concrete below.

Early on Monday 14 PCV venting was repeated, and this evidently backflowed to the service floor of the building, so that at 11:00 am a very large hydrogen explosion here above unit 3 reactor containment blew off much of the roof and walls and demolished the top part of the building. This explosion created a lot of debris, and some of that on the ground near unit 3 was very radioactive.

In defuelled unit 4, at about 6:00 am on Tuesday 15 March, there was an explosion which destroyed the top of the building and damaged unit 3's superstructure further. This was apparently from hydrogen arising in unit 3 and reaching unit 4 by backflow in shared ducts when vented from unit 3.

Units 1-3: Water had been injected into each of the three reactor units more or less continuously, and in the absence of normal heat removal via external heat exchanger this water was boiling off for some months. In the government report to the IAEA in June it was estimated that to the end of May about 40% of the injected water boiled off, and 60% leaked out the bottom. In June 2011 this was adding to the contaminated water onsite by about 500 m ³ per day. In January 2013 4.5 to 5.5 m ³/h was being added to each RPV via core spray and feedwater systems, hence 370 m ³ per day, and temperatures at the bottom of RPVs were 19 °C in unit 1 and 32 °C in units 2&3, at little above atmospheric pressure.

There was a peak of radioactive release on Tuesday 15, apparently mostly from unit 2, but the precise source remains uncertain. Due to volatile and easily-airborne fission products being carried with the hydrogen and steam, the venting and hydrogen explosions discharged a lot of radioactive material into the atmosphere, notably iodine and caesium. NISA said in June that it estimated that 800-1000 kg of hydrogen had been produced in each of the units.

Nitrogen was being injected into the PCVs of all three reactors to remove concerns about further hydrogen explosions, and in December this was started also for the pressure vessels. Gas control systems which extract and clean the gas from the PCV to avoid leakage of caesium were commissioned for all three units.

Throughout 2011 injection into the RPVs of water circulated through the new water treatment plant achieved relatively effective cooling, and temperatures at the bottom of the RPVs were stable in the range 60-76 °C at the end of October, and 27-54 °C in mid-January 2012. RPV pressures ranged from atmospheric to slightly above (102-109 kPa) in January, due to water and nitrogen injection. However, since they were leaking, the normal definition of 'cold shutdown' did not apply, and Tepco waited to bring radioactive releases under control before declaring 'cold shutdown condition' in mid-December, with NISA's approval. This, with the prime minister's announcement of it, formally brought to a close the 'accident' phase of events.

The AC electricity supply from external source was connected to all units by 22 March. Power was restored to instrumentation in all units except unit 3 by 25 March. However, radiation levels inside the plant were so high that normal access was impossible until June.

Event sequence following earthquake (timing from it: 14:46, 11 March)

By March 2016 total decay heat in units 1-3 had dropped to 1 MW for all three, about 1% of the original level, meaning that cooling water injection - then 100 m ³/d - could be interrupted for up to two days.

Results of muon measurements in unit 2 in 2016 indicate that most of the fuel debris in unit 2 is in the bottom of the reactor vessel.

Tepco has written off the four reactors damaged by the accident, and is decommissioning them.

Summary: Major fuel melting occurred early on in all three units, though the fuel remained essentially contained except for some volatile fission products vented early on, or released from unit 2 in mid-March, and some soluble ones which were leaking with the water, especially from unit 2, where the containment is evidently breached. Cooling is provided from external sources, using treated recycled water, with a stable heat removal path from the actual reactors to external heat sinks. Access has been gained to all three reactor buildings, but dose rates remain high inside. Tepco declared 'cold shutdown condition' in mid-December 2011 when radioactive releases had reduced to minimal levels.

(See also background on nuclear reactors at Fukushima Daiichi.)

Fuel ponds: developing problems

Used fuel needs to be cooled and shielded. This is initially by water, in ponds. After about three years underwater, used fuel can be transferred to dry storage, with air ventilation simply by convection. Used fuel generates heat, so the water in ponds is circulated by electric pumps through external heat exchangers, so that the heat is dumped and a low temperature maintained. There are fuel ponds near the top of all six reactor buildings at the Daiichi plant, adjacent to the top of each reactor so that the fuel can be unloaded underwater when the top is off the reactor pressure vessel and it is flooded. The ponds hold some fresh fuel and some used fuel, the latter pending its transfer to the onsite central used/spent fuel storage. (There is some dry storage onsite to extend the plant's capacity.)

At the time of the accident, in addition to a large number of used fuel assemblies, unit 4's pond also held a full core load of 548 fuel assemblies while the reactor was undergoing maintenance, these having been removed at the end of November, and were to be replaced in the core.

A separate set of problems arose as the fuel ponds, holding fresh and used fuel in the upper part of the reactor structures, were found to be depleted in water. The primary cause of the low water levels was loss of cooling circulation to external heat exchangers, leading to elevated temperatures and probably boiling, especially in the heavily-loaded unit 4 fuel pond. Here the fuel would have been uncovered in about 7 days due to water boiling off. However, the fact that unit 4 was unloaded meant that there was a large inventory of water at the top of the structure, and enough of this replenished the fuel pond to prevent the fuel becoming uncovered - the minimum level reached was about 1.2 m above the fuel on about 22 April.

After the hydrogen explosion in unit 4 early on Tuesday 15 March, Tepco was told to implement injection of water to unit 4 pond which had a particularly high heat load (3 MW) from 1331 used fuel assemblies in it, so it was the main focus of concern. It needed the addition of about 100 m ³/day to replenish it after circulation ceased.

From Tuesday 15 March attention was given to replenishing the water in the ponds of units 1, 2&3 as well. Initially this was attempted with fire pumps but from 22 March a concrete pump with 58-metre boom enabled more precise targeting of water through the damaged walls of the service floors. There was some use of built-in plumbing for unit 2. Analysis of radionuclides in water from the used fuel ponds suggested that some of the fuel assemblies might have been damaged, but the majority were intact.

There was concern about the structural strength of unit 4 building, so support for the pond was reinforced by the end of July.

New cooling circuits with heat exchangers adjacent to the reactor buildings for all four ponds were commissioned after a few months, and each reduced the pool temperature from 70 °C to normal in a few days. Each has a primary circuit within the reactor and waste treatment buildings and a secondary circuit dumping heat through a small dry cooling tower outside the building.

The next task was to remove the salt from those ponds which had seawater added, to reduce the potential for corrosion.

In July 2012 two of the 204 fresh fuel assemblies were removed from the unit 4 pool and transferred to the central spent fuel pool for detailed inspection to check damage, particularly corrosion. They were found to have no deformation or corrosion. Unloading the 1331 spent fuel assemblies in pond 4 and transferring them to the central spent fuel pool commenced in mid-November 2013 and was completed 13 months later. These comprised 783 spent fuel plus the full fuel load of 548.

The next focus of attention was the unit 3 pool. In 2015 the damaged fuel handling equipment and other wreckage was removed from the destroyed upper level of the reactor building. Toshiba built a 74-tonne fuel handling machine for transferring the 566 fuel assemblies into casks and to remove debris in the pool, and a crane for lifting the fuel transfer casks. Installation of a cover over the fuel handling machine was completed in February 2018. Removal and transferral of the fuel to the central spent fuel pool began in mid-April 2019 and was completed at the end of February 2021.

The onsite central spent fuel pool in 2011 held about 60% of the Daiichi used fuel, and is immediately west (inland) of unit 4. It lost circulation with the power outage, and temperature increased to 73 °C by the time mains power and cooling were restored after two weeks. In late 2013 this pond, with capacity for 6840*, held 6375 fuel assemblies, the same as at the time of the accident. In June 2018, Tepco announced it would transfer some of the fuel assemblies stored in the central spent fuel pool to an onsite temporary dry storage facility to clear sufficient space for the fuel assemblies from unit 3's pool. The dry storage facility has a capacity of at least 2930 assemblies in 65 casks - each dry cask holds 50 fuel assemblies. Eventually these will be shipped to JNFL's Rokkasho reprocessing plant or to Recyclable Fuel Storage Company's Mutsu facility.

Summary: The spent fuel storage pools survived the earthquake, tsunami and hydrogen explosions without significant damage to the fuel, significant radiological release, or threat to public safety. The new cooling circuits with external heat exchangers for the four ponds are working well and temperatures are normal. Analysis of water has confirmed that most fuel rods are intact. All fuel assemblies have been removed from the unit 3&4 pools.

(See also background on Fukushima Fuel Ponds and Decommissioning section below.)

Radioactive releases to air

Regarding releases to air and also water leakage from Fukushima Daiichi, the main radionuclide from among the many kinds of fission products in the fuel was volatile iodine-131, which has a half-life of 8 days. The other main radionuclide is caesium-137, which has a 30-year half-life, is easily carried in a plume, and when it lands it may contaminate land for some time. It is a strong gamma-emitter in its decay. Cs-134 is also produced and dispersed; it has a two-year half-life. Caesium is soluble and can be taken into the body, but does not concentrate in any particular organs, and has a biological half-life of about 70 days. In assessing the significance of atmospheric releases, the Cs-137 figure is multiplied by 40 and added to the I-131 number to give an 'iodine-131 equivalent' figure.

As cooling failed on the first day, evacuations were progressively ordered, due to uncertainty about what was happening inside the reactors and the possible effects. By the evening of Saturday 12 March the evacuation zone had been extended to 20 km from the plant. From 20 to 30 km from the plant, the criterion of 20 mSv/yr dose rate was applied to determine evacuation, and is now the criterion for return being allowed. 20 mSv/yr was also the general limit set for children's dose rate related to outdoor activities, but there were calls to reduce this. In areas with 20-50 mSv/yr from April 2012 residency is restricted, with remediation action taken. See later section on Public health and return of evacuees.

A significant problem in tracking radioactive release was that 23 out of the 24 radiation monitoring stations on the plant site were disabled by the tsunami.

There is some uncertainty about the amount and exact sources of radioactive releases to air (see also background on Radiation Exposure).

Japan's regulator, the Nuclear & Industrial Safety Agency (NISA), estimated in June 2011 that 770 PBq (iodine-131 equivalent) of radioactivity had been released, but the Nuclear Safety Commission (NSC, a policy body) in August lowered this estimate to 570 PBq. The 770 PBq figure is about 15% of the Chernobyl release of 5200 PBq iodine-131 equivalent. Most of the release was by the end of March 2011.

Tepco sprayed a dust-suppressing polymer resin around the plant to ensure that fallout from mid-March was not mobilized by wind or rain. In addition it removed a lot of rubble with remote control front-end loaders, and this further reduced ambient radiation levels, halving them near unit 1. The highest radiation levels onsite came from debris left on the ground after the explosions at units 3&4.

Reactor covers

In mid-May 2011 work started towards constructing a cover over unit 1 to reduce airborne radioactive releases from the site, to keep out the rain, and to enable measurement of radioactive releases within the structure through its ventilation system. The frame was assembled over the reactor, enclosing an area 42 x 47 m, and 54 m high. The sections of the steel frame fitted together remotely without the use of screws and bolts. All the wall panels had a flameproof coating, and the structure had a filtered ventilation system capable of handling 40,000 cubic metres of air per hour through six lines, including two backup lines. The cover structure was fitted with internal monitoring cameras, radiation and hydrogen detectors, thermometers and a pipe for water injection. The cover was completed with ventilation systems working by the end of October 2011. It was expected to be needed for two years. In May 2013 Tepco announced its more permanent replacement, to be built over four years. It started demolishing the 2011 cover in 2014 and finished in 2016. In December 2019 it decided to install the replacement cover before removing debris from the top floor of the building. A crane and other equipment for fuel removal will be installed under the cover, similar to that over unit 4.

More substantial covers were designed to fit around units 3&4 reactor buildings after the top floors were cleared up in 2012.

A cantilevered structure was built over unit 4 from April 2012 to July 2013 to enable recovery of the contents of the spent fuel pond. This is a 69 x 31 m cover (53 m high) and it was fully equipped by the end of 2013 to enable unloading of used fuel from the storage pond into casks, each holding 22 fuel assemblies, and removal of the casks. This operation was accomplished under water, using the new fuel handling machine (replacing the one destroyed by the hydrogen explosion) so that the used fuel could be transferred to the central storage onsite. Transfer was completed in December 2014. A video of the process is available on Tepco's website.

A different design of cover was built over unit 3, and foundation work began in 2012. Large rubble removal took place from 2013 to 2015, including the damaged fuel handling machine. An arched cover was prefabricated, 57 m long and 19 m wide, and supported by the turbine building on one side and the ground on the other. A crane removed the 566 fuel assemblies from the pool and some remaining rubble. Spent fuel removal from unit 3 pool began in April 2019 and was completed in February 2021. Spent fuel removal from units 1&2 pools was scheduled in 2018, but is now scheduled to begin in 2023.

Maps from the Ministry of Education, Culture, Sports, Science and Tehcnology (MEXT) aerial surveys carried out approximately one year apart show the reduction in contamination from late 2011 to late 2012. Areas with colour changes in 2012 showed approximately half the contamination as surveyed in 2011, the difference coming from decay of caesium-134 (two-year half-life) and natural processes like wind and rain. In blue areas, ambient radiation is very similar to global background levels at <0.5 microsieverts per hour, which is equal to <4.4 mSv/yr.

Tests on radioactivity in rice have been made and caesium was found in a few of them. The highest levels were about one-quarter of the allowable limit of 500 Bq/kg, so shipments to market are permitted.

Summary: Major releases of radionuclides, including long-lived caesium, occurred to air, mainly in mid-March. The population within a 20km radius had been evacuated three days earlier. Considerable work was done to reduce the amount of radioactive debris onsite and to stabilize dust. The main source of radioactive releases was the apparent hydrogen explosion in the suppression chamber of unit 2 on 15 March. A cover building for unit 1 reactor was built and the unit is now being dismantled, a more substantial one for unit 4 was built to enable fuel removal during 2014. Radioactive releases in mid-August 2011 had reduced to 5 GBq/hr, and dose rate from these at the plant boundary was 1.7 mSv/yr, less than natural background.

Sequence of evacuation orders based on the report by The National Diet of Japan Fukushima Nuclear Accident Independent Investigation Commission:

11 March
14:46 JST The earthquake occurred.
15:42 TEPCO made the first emergency report to the government.
19:03 The government announced nuclear emergency.
20:50 The Fukushima Prefecture Office ordered 2km radius evacuation.
21:23 The government ordered 3km evacuation and to keep staying inside buildings in the area of 3-10km radius.

12 March
05:44 The government ordered 10km radius evacuation.
18:25 The government ordered 20km evacuation.

15 March
11:01 The government ordered to keep staying inside buildings in the area of 20-30km from the plant.

25 March The government requested voluntary evacuation in the area of 20-30km.

21 April The government set the 20km radius no-go area.

Radiation exposure on the plant site

By the end of 2011, Tepco had checked the radiation exposure of 19,594 people who had worked on the site since 11 March. For many of these both external dose and internal doses (measured with whole-body counters) were considered. It reported that 167 workers had received doses over 100 mSv. Of these 135 had received 100 to 150 mSv, twenty-three 150-200 mSv, three more 200-250 mSv, and six had received over 250 mSv (309 to 678 mSv) apparently due to inhaling iodine-131 fumes early on. The latter included the units 3&4 control room operators in the first two days who had not been wearing breathing apparatus. There were up to 200 workers onsite each day. Recovery workers wear personal monitors, with breathing apparatus and protective clothing which protect against alpha and beta radiation. The level of 250 mSv was the allowable maximum short-term dose for Fukushima Daiichi accident clean-up workers through to December 2011, 500 mSv is the international allowable short-term dose "for emergency workers taking life-saving actions". In January 2012 the allowable maximum reverted to 50 mSv/yr.

No radiation casualties (acute radiation syndrome) occurred, and few other injuries, though higher than normal doses, were being accumulated by several hundred workers onsite. High radiation levels in the three reactor buildings hindered access there.

Monitoring of seawater, soil and atmosphere is at 25 locations on the plant site, 12 locations on the boundary, and others further afield. Government and IAEA monitoring of air and seawater is ongoing. Some high but not health-threatening levels of iodine-131 were found in March, but with an eight-day half-life, most I-131 had gone by the end of April 2011.

A radiation survey map of the site made in March 2013 revealed substantial progress: the highest dose rate anywhere on the site was 0.15 mSv/h near units 3 and 4. (Soon after the accident a similar survey put the highest dose rate at 300 mSv/h near rubble lying alongside unit 3.) The majority of the power plant area was at less than 0.01 mSv/h. These reduced levels are reflected in worker doses: during January 2013, the 5702 workers at the site received an average of 0.86 mSv, with 75% of workers recorded as receiving less than 1 mSv. In total, only about 2% of workers received over 5 mSv and the highest dose in January was 12.65 mSv for one worker.

Media reports have referred to 'nuclear gypsies' - casual workers employed by subcontractors on a short-term basis, and allegedly prone to receiving higher and unsupervised radiation doses. This transient workforce has been part of the nuclear scene for at least four decades, and at Fukushima their doses are very rigorously monitored. If they reach certain levels, e.g. 30 mSv but varying according to circumstance, they are reassigned to lower-exposure areas.

Tepco figures submitted to the NRA for the period to end January 2014 showed 173 workers had received more than 100 mSv (six more than two years earlier) and 1578 had received 50 to 100 mSv. This was among a total of 32,024, 64% more than had worked there two years earlier. Since April 2013 none of the 13,154 who had worked onsite had received more than 50 mSv, and 96% of these had less than a 20 mSv dose. Early in 2014 there were about 4000 onsite each weekday.

Summary: Six workers received radiation doses apparently over the 250 mSv level set by NISA, but at levels below those which would cause radiation sickness.

Radiation exposure and fallout beyond the plant site

On 4 April 2011, radiation levels of 0.06 mSv/day were recorded in Fukushima city, 65 km northwest of the plant, about 60 times higher than normal but posing no health risk according to authorities. Monitoring beyond the 20 km evacuation radius to 13 April showed one location - around Iitate - with up to 0.266 mSv/day dose rate, but elsewhere no more than one-tenth of this. At the end of July the highest level measured within 30km radius was 0.84 mSv/day in Namie town, 24 km away. The safety limit set by the central government in mid-April for public recreation areas was 3.8 microsieverts per hour (0.09 mSv/day).

In June 2013, analysis from Japan's Nuclear Regulation Authority (NRA) showed that the most contaminated areas in the Fukushima evacuation zone had reduced in size by three-quarters over the previous two years. The area subject to high dose rates (over 166 mSv/yr) diminished from 27% of the 1117 km ² zone to 6% over 15 months to March 2013, and in the 'no residence' portion (originally 83-166 mSv/yr) no areas remained at this level and 70% was below 33 mSv/yr. The least-contaminated area is now entirely below 33 mSv/yr.

In August 2011 The Act on Special Measures Concerning the Handling of Radioactive Pollution was enacted and it took full effect from January 2012 as the main legal instrument to deal with all remediation activities in the affected areas, as well as the management of materials removed as a result of those activities. It specified two categories of land:
Special Decontamination Areas consisting of the 'restricted areas' located within a 20 km radius from the Fukushima Daiichi plant, and 'deliberate evacuation areas' where the annual cumulative dose for individuals was anticipated to exceed 20 mSv. The national government promotes decontamination in these areas. These areas are subdivided into three: dose 1-20 mSv/yr (green); dose 20-50 mSv/yr (yellow); and dose over 50 mSv/yr and over 20 mSv/yr averaged over 5 years (red).
Intensive Contamination Survey Areas including the so-called Decontamination Implementation Areas, where an additional annual cumulative dose between 1 mSv and 20 mSv was estimated for individuals. Municipalities implement decontamination activities in these areas.

Following a detailed study by 80 international experts, the UN Scientific Committee on the Effects of Atomic Radiation's (UNSCEAR's) May 2013 Report to the General Assembly concluded: "No radiation-related deaths or acute diseases have been observed among the workers and general public exposed to radiation from the accident. The doses to the general public, both those incurred during the first year and estimated for their lifetimes, are generally low or very low. No discernible increased incidence of radiation-related health effects are expected among exposed members of the public or their descendants."

However, the report noted: "More than 160 additional workers received effective doses currently estimated to be over 100 mSv, predominantly from external exposures. Among this group, an increased risk of cancer would be expected in the future. However, any increased incidence of cancer in this group is expected to be indiscernible because of the difficulty of confirming such a small incidence against the normal statistical fluctuations in cancer incidence."

These workers are individually monitored annually for potential late radiation-related health effects. UNSCEAR's follow-up white paper in October 2015 said that none of the new information appraised after the 2013 report "materially affected the main findings or challenged the major assumptions of the 2013 Fukushima report."

By contrast, the public was exposed to 10-50 times less radiation. Most Japanese people were exposed to additional radiation amounting to less than the typical natural background level of 2.1 mSv per year.

In 2018 UNSCEAR decided to update the 2013 report to reflect the latest findings. In March 2021, UNSCEAR published its 2020 Report, which broadly confirms the major findings and conclusions of the 2013 report. The 2020 Report states: "No adverse health effects among Fukushima residents have been documented that are directly attributable to radiation exposure from the Fukushima Daiichi nuclear plant accident. The Committee's revised estimates of dose are such that future radiation-associated health effects are unlikely to be discernible."

People living in Fukushima prefecture are expected to be exposed to around 10 mSv over their entire lifetimes, while for those living further away the dose would be 0.2 mSv per year. The UNSCEAR conclusion reinforces the findings of several international reports to date, including one from the World Health Organization (WHO) that considered the health risk to the most exposed people possible: a postulated girl under one year of age living in Iitate or Namie that did not evacuate and continued life as normal for four months after the accident. Such a child's theoretical risk of developing any cancer would be increased only marginally, according to the WHO's analysis.

Despite the conclusions of reports from UNSCEAR and the WHO, the Japanese government in 2018 acknowledged a connection between the death of a former plant worker and radiation exposure. The man had been diagnosed with lung cancer in February 2016.

Eleven municipalities in the former restricted zone or planned evacuation area, within 20 km of the plant or where annual cumulative radiation dose is greater than 20 mSv, are designated 'special decontamination areas', where decontamination work is being implemented by the government. A further 100 municipalities in eight prefectures, where dose rates are equivalent to over 1 mSv per year are classed as 'intensive decontamination survey areas', where decontamination is being implemented by each municipality with funding and technical support from the national government. Decontamination of all 11 special decontamination areas has been completed.

In October 2013 a 16-member IAEA mission reported on remediation and decontamination in the special decontamination areas. Its preliminary report said that decontamination efforts were commendable but driven by unrealistic targets. If annual radiation dose was below 20 mSv, such as generally in intensive decontamination survey areas, this level was "acceptable and in line with the international standards and with the recommendations from the relevant international organizations, e.g. ICRP, IAEA, UNSCEAR and WHO." The clear implication was that people in such areas should be allowed to return home. Furthermore the government should increase efforts to communicate this to the public, and should explain that its long-term goal of achieving an additional individual dose of 1 mSv/yr is unrealistic and unnecessary in the short term. Also, there is potential to produce more food safely in contaminated areas.

Radioactivity, primarily from caesium-137, in the evacuation zone and other areas beyond it has been reported in terms of kBq/kg (compared with kBq/m ² around Chernobyl. A total of 3000 km was contaminated above 180 kBq/m ², compared with 29,400 km from Chernobyl). However the main measure has been presumed doses in mSv/yr. The government has adopted 20 mSv/yr as its goal for the evacuation zone and more contaminated areas outside it, and supports municipal government work to reduce levels below that. The total area under consideration for attention is 13,000 km ². In 2016 the Ministry of Environment announced that material with less than 8 kBq/kg caesium would no longer be specified as waste, and subject to restrictions on disposal. It allowed use of contaminated soil for embankments, where the activity was less then 8 kBq/kg, and unrestricted use if less than 100 Bq/kg. Most of the stored wastes have decayed to below the 8 kBq/kg level.

Summary: There have been no harmful effects from radiation on local people, nor any doses approaching harmful levels. However, some 160,000 people were evacuated from their homes and only from 2012 were allowed limited return. As of July 2020 over 41,000 remained displaced due to government concern about radiological effects from the accident.

Public health and return of evacuees

Permanent return remains a high priority, and the evacuation zone is being decontaminated where required and possible, so that evacuees can return. There are many cases of evacuation stress including transfer trauma among evacuees, and once the situation had stabilized at the plant these outweighed the radiological hazards of returning, with 2313 deaths reported (see below).

In December 2011 the government said that where annual radiation dose would be below 20 mSv/yr, the government would help residents return home as soon as possible and assist local municipalities with decontamination and repair of infrastructure. In areas where radiation levels are over 20 mSv/yr evacuees will be asked to continue living elsewhere for "a few years" until the government completes decontamination and recovery work. The government said it would consider purchasing land and houses from residents of these areas if the evacuees wish to sell them.

In November 2013 the NRA decided to change the way radiation exposure was estimated. Instead of airborne surveys being the basis, personal dosimeters would be used, giving very much more accurate figures, often much less than airborne estimates. The same criteria would be used, as above, with 20 mSv/yr being the threshold of concern to authorities.

In February 2014 the results of a study were published showing that 458 residents of two study areas 20 to 30 km from the plant and a third one 50 km northwest received radiation doses from the contaminated ground similar to the country's natural background levels. Measurement was by personal dosimeters over August-September 2012.

By September 2020, 2313 disaster-related deaths among evacuees from Fukushima prefecture*, that were not due to radiation-induced damage or to the earthquake or to the tsunami, had been identified by the Japanese authorities. About 90% of deaths were for persons above 66 years of age. Of these, about 30% occurred within the first three months of the evacuations, and about 80% within two years.

* An additional 1454 disaster-related deaths have been reported among evacuees from other tsunami- and earthquake-related prefectures. Disaster-related deaths are in addition to the over 19,500 that died in the actual earthquake and tsunami.

The premature disaster-related deaths were mainly related to (i) physical and mental illness brought about by having to reside in shelters and the trauma of being forced to move from care settings and homes; and (ii) delays in obtaining needed medical support because of the enormous destruction caused by the earthquake and tsunami.

However, the radiation levels in most of the evacuated areas were not greater than the natural radiation levels in high background areas elsewhere in the world where no adverse health effect is evident.

In its December 2018 report, the Fukushima prefectural government said that the number of 'indirect' deaths in the prefecture was greater than the number (1829) killed in the earthquake and tsunami. It put the figure then at 2259 (since revised up to 2313) as determined by municipal panels that examine links between the disaster's aftermath and deaths. The figure is greater than for Iwate and Miyagi prefectures, with 469 and 929 respectively, though they had much higher loss of life in the earthquake and tsunami - over 14,000. The disparity is attributed to the older age group involved among Fukushima's evacuated earthquake/tsunami survivors, about 90% of indirect deaths being of people over 66. Causes of indirect deaths include physical and mental stress stemming from long stays at shelters, a lack of initial care as a result of hospitals being disabled by the disaster, and suicides. Evaluation of 'indirect deaths' is according to a model developed by Niigata prefecture after the 2004 earthquake there ( Japan Times 20/2/14). As of July 2020, over 41,000 people from Fukushima were still living as evacuees.

Evacuees over a period of six years received ¥100,000 (about $1000) per month in psychological suffering compensation. The money was tax-exempt and paid unconditionally. In October 2013, about 84,000 evacuees received the payments. Statistics indicate that an average family of four has received about ¥90 million ($900,000) in compensation from Tepco. As of January 2021 the Fukushima accident evacuees had received ¥9.7 trillion in personal and property compensation.

The Fukushima prefecture had 17,000 government-financed temporary housing units for some 29,500 evacuees from the accident. The prefectural government said residents could continue to use these until March 2015 ( Japan Times 17/11/13). The number compared with very few built in Miyagi, Iwate and Aomori prefectures for the 222,700 tsunami survivor refugees there.

In April 2019, the first residents of Okuma, the closest town to the plant, were allowed to return home. In August 2022 the last remaining evacuation order - for Futaba, the town that hosts the Fukushima plant - was lifted.

According to a survey released by the prefectural government in April 2017, the majority of people who voluntarily evacuated their homes after the accident and who are now living outside of Fukushima prefecture do not intend to return. A Mainichi report said that 78.2% of respondents to the survey preferred to continue living in the area to which they had moved, while only 18.3% intended to move back to the prefecture. Of the voluntary evacuees still living in Fukushima prefecture, 23.6% planned to stay where they were, while 66.6% hoped to return to their original homes.

An August 2012 Reconstruction Agency report also considered workers at Fukushima power plant. Of almost 1500 surveyed, many were stressed, due to evacuating their homes (70%), believing they had come close to death (53%), the loss of homes in the tsunami (32%), deaths of colleagues (20%) and of family members (6%) mostly in the tsunami. The death toll directly due to the nuclear accident or radiation exposure remained zero, but stress and disruption due to the continuing evacuation remains high.

Tokyo's Board of Audit reported in October 2013 that 23% of recovery funding - about ¥1.45 trillion ($14.5 billion) - had been misappropriated. Some 326 out of about 1400 projects funded had no direct relevance to the natural disaster or Fukushima Daiichi accident (Mainichi 1/11/13).

Summary: Many evacuated people remain unable to fully return home due to government-mandated restrictions based on conservative radiation exposure criteria. 2313 premature disaster-related deaths were caused by the evacuations, with 90% of the deaths occuring in people aged 66 and older. Decontamination work is proceeding while radiation levels decline naturally. The October 2013 IAEA report made clear that many evacuees should be allowed to return home. As of July 2020, over 41,000 people from Fukushima were still living as evacuees.

Managing contaminated water

Removing contaminated water from the reactor and turbine buildings had become the main challenge by week 3, along with contaminated water in trenches carrying cabling and pipework. This was both from the tsunami inundation and leakage from reactors. Run-off from the site into the sea was also carrying radionuclides well in excess of allowable levels. By the end of March all storages around the four units - basically the main condenser units and condensate tanks - were largely full of contaminated water pumped from the buildings.

Accordingly, with government approval, Tepco over 4-10 April released to the sea about 10,400 cubic metres of slightly contaminated water (0.15 TBq total) in order to free up storage for more highly-contaminated water from unit 2 reactor and turbine buildings which needed to be removed to make safe working conditions. Unit 2 was the main source of contaminated water, though some of it comes from drainage pits. NISA confirmed that there was no significant change in radioactivity levels in the sea as a result of the 0.15 TBq discharge in April 2011.

By the end of June 2011, Tepco had installed 109 concrete panels to seal the water intakes of units 1-4, preventing contaminated water leaking to the harbour. From mid-June some treatment with zeolite of seawater at 30 m ³/hr was being undertaken near the water intakes for units 2&3, inside submerged barriers installed in April. From October, a steel water shield wall was built on the sea frontage of units 1-4. It extends about one kilometre, and down to an impermeable layer beneath two permeable strata which potentially leak contaminated groundwater to the sea. The inner harbour area which has some contamination is about 30 ha in area. The government in September 2013 said: "At present, statistically-significant increase of radioactive concentration in the sea outside the port of the Tepco's Fukushima Daiichi NPS has not been detected." And also: "The results of monitoring of seawater in Japan are constantly below the standard of 10 Bq/L" (the WHO standard for Cs-137 in drinking water). In 2012 the Japanese standard for caesium in food supply was dropped from 500 to 100 Bq/kg. In July-August 2014 only 0.6% of fish caught offshore from the plant exceeded this lower level, compared with 53% in the months immediately following the accident.

Long-term management and disposal

Tepco in 2011 built a new wastewater treatment facility to treat contaminated water. The company used both US proprietary adsorption and French conventional technologies in the new 1200 m ³/day treatment plant. A supplementary and simpler SARRY (simplified active water retrieve and recovery system) plant to remove caesium using Japanese technology and made by Toshiba and The Shaw Group was installed and commissioned in August 2011. These plants reduce caesium from about 55 MBq/L to 5.5 kBq/L - about ten times better than designed. Desalination is necessary on account of the seawater earlier used for cooling, and the 1200 m ³/day desalination plant produces 480 m ³ of clean water while 720 m ³ goes to storage. A steady increase in volume of the stored water (about 400 m ³/d net) is due to groundwater finding its way into parts of the plant and needing removal and treatment.

Some 1000 storage tanks were set up progressively after the accident, including initially 350 steel tanks with rubber seams, each holding 1200 m ³. A few of these developed leaks in 2013.

Early in 2013 Tepco started to test and commission the Advanced Liquid Processing System ( ALPS), developed by EnergySolutions and Toshiba. Each of six trains is capable of processing 250 m ³/day to remove 62 remaining radioisotopes. By the end of 2014, an ALPS of 500 m ³/d had been added, making total capacity 2000 m ³/d. The NRA approved the extra capacity in August 2014.

Earlier in September 2013 report from the Atomic Energy Society of Japan recommended diluting the ALPS-treated water with seawater and releasing it to the sea at the legal discharge concentration of 0.06 MBq/L, with monitoring to ensure that normal background tritium levels of 10 Bq/L are not exceeded. (The WHO drinking water guideline is 0.01 MBq/L tritium.) The IAEA supports release of tritiated water to the ocean, as does Dale Klein, chairman of Tepco's Nuclear Reform Monitoring Committee (NRMC) and former chairman of the US Nuclear Regulatory Commission.

ALPS is a chemical system which removes radionuclides to below legal limits for release. However, because tritium is contained in water molecules, ALPS cannot remove it, which gives rise to questions about the discharge of treated water to the sea. Tritium is a weak beta-emitter which does not bio-accumulate (half-life 12 years), and its concentration has levelled off at about 1 MBq/L in the stored water, with dilution from groundwater balancing further release from the fuel debris.

In 2014 a new Kurion strontium removal system was commissioned. This is mobile and can be moved around the tank groups to further clean up water which has been treated by ALPS.

In June 2015 108 m ³/day of clean water was being circulated through each reactor (units 1-3). Collected water from them, with high radioactivity levels, was being treated for caesium removal and re-used. Apart from this recirculating loop, the cumulative treated volume was then 1.232 million cubic metres. In storage onsite was 459,000 m ³ of fully treated water (by ALPS), and 190,000 m ³ of partially-treated water (strontium removed), which was being added to at 400 m ³/day due to groundwater inflow. Almost 600 m ³ of sludge from the water treatment was stored in shielded containers.

In 2016 Kurion (now owned by Veolia) completed a demonstration project for tritium removal at low concentrations, with its new Modular Detritiation System (MDS),* in response to a ¥1 billion commission from METI.

* In this, an electrolyser produces hydrogen and oxygen, with the tritium reporting in the hydrogen. This is fed through a catalytic exchange column with a little water which preferentially takes up the tritium. The concentrated tritiated water is fed through a 'getter bed' of dry metal hydrate, where the tritium replaces hydrogen, and the material is stored, being stable up to 500 °C. It can be incorporated into concrete and disposed as low-level waste. The tritium is concentrated 1000 to 20,000 times. The MDS is the first system to be able economically to treat large volumes of water with low tritium concentrations, and builds on existing heavy water tritium removal systems. Each module treats up to 7200 litres per day.

In November 2019 the trade and industry ministry stated that annual radiation levels from the release of the tritium-tainted water are estimated at between 0.052 and 0.62 microsieverts if it were disposed of at sea and 1.3 microsieverts if it were released into the atmosphere, compared with the 2100 microsieverts (2.1 mSv) that humans are naturally exposed to annually.

In March 2020, TEPCO released a study in relation to two disposal methods of the ALPS-treated water - discharge into the sea and vapour discharge.

In April 2021 the Japanese government confirmed that the water would be released into the sea in 2023. In August 2021 Tepco announced plans for the construction of an undersea tunnel about 1 kilometre in length, which will allow the release of the water into an area where no fishing rights are in place. In May 2022 the NRA endorsed Tepco's plans.

ALPS-treated water is currently stored in more than 1000 tanks onsite with a storage capacity of 1.37 million cubic metres which are expected to reach full capacity by late 2023 or early 2024. Some of the ALPS treated water will require secondary processing to further reduce concentrations of radionuclides in line with government requirements.

In August 2023 the Japanese government asked Tepco to begin preparations for the release of the treated water, with the first water set to be discharged from 24 August 2023. Tepco plans to discharge the water using a two-step process. First, a small amount of treated water will be diluted with seawater and stored in a vertical discharge shaft in order to sample, measure and verify the tritium levels of the water. The water will then be discharged into the sea via the 1km undersea tunnel. The IAEA opened an office at the Fukushima Daiichi plant in July 2023 in order to continuously monitor and assess the activities related to the release of the treated water and ensure alignment with safety standards. The IAEA will also provide real-time monitoring data.

Apart from the above-ground water treatment activity, there is now a groundwater bypass to reduce the groundwater level above the reactors by about 1.5 metres, pumping from 12 wells and from May 2014, discharging the uncontaminated water into the sea. This prevents some of it flowing into the reactor basements and becoming contaminated. In addition, an impermeable wall was constructed on the sea-side of the reactors, and inside this a frozen soil wall was created to further block water flow into the reactor buildings.

In October 2013 guidelines for rainwater release from the site allowed Tepco to release water to the sea without specific NRA approval as long as it conformed to activity limits. Tepco has been working to 25 Bq/L caesium and 10 Bq/L strontium-90.

Summary: A large amount of contaminated water has accumulated onsite and has been treated to remove radioactive elements, apart from tritium. In April 2021, the Japanese government confirmed that the water would be released into the sea. Some radioactivity has already been released to the sea, but this has mostly been low-level and it has not had any significant impact beyond the immediate plant structures. Concentrations outside these structures have been below regulatory levels since April 2011. The release of the treated water will commence in August 2023 and will be continuously monitored by IAEA staff present at the site.

IRID and NDF involvement

The International Research Institute for Nuclear Decommissioning ( IRID) was set up in August 2013 Japan by the Japan Atomic Energy Agency (JAEA), Japanese utilities and reactor vendors, with a focus on Fukushima Daiichi 1-4.

In September 2013 IRID called for submissions on the management of contaminated water at Fukushima. In particular, proposals were sought for dealing with: the accumulation of contaminated water (in storage tanks, etc); the treatment of contaminated water including tritium removal; the removal of radioactive materials from the seawater in the plant's 30 ha harbour; the management of contaminated water inside the buildings; measures to block groundwater from flowing into the site; and, understanding the flow of groundwater. Responses were submitted to the government in November.

In December 2013 IRID called for innovative proposals for removing fuel debris from units 1-3 about 2020.

In August 2014 the Nuclear Damage Compensation and Decommissioning Facilitation Corporation (NDF) was set up by the government as a planning body with management support for R&D projects, taking over IRID's planning role. It works with IRID, whose focus now is on developing mid- and long-term decommissioning technologies. The NDF also works with Tepco Fukushima Daiichi D&D Engineering Co., which has responsibility for operating the actual decommissioning work there. The NDF will be the main body interacting with the government (METI) to implement policy.

Fukushima Daiichi 5&6

Units 5&6, in a separate building, also lost power on 11 March due to the tsunami. They were in 'cold shutdown' at the time, but still requiring pumped cooling. One air-cooled diesel generator at unit 6 was located higher and so survived the tsunami and enabled repairs on Saturday 19, allowing full restoration of cooling for units 5&6. While the power was off their core temperature had risen to over 100 °C (128 °C in unit 5) under pressure, and they had been cooled with normal water injection. They were restored to cold shutdown by the normal recirculating system on 20 March, and mains power was restored on 21-22 March.

In September 2013 Tepco commenced work to remove the fuel from unit 6. Prime minister Abe then called for Tepco to decommission both units. Tepco announced in December 2013 that it would decommission both units from the end of January 2014. Unit 5 was a 760 MWe BWR the same as units 2-4, and unit 6 was larger - 1067 MWe. They entered commercial operation in 1978 and 1979 respectively. It is proposed that they will be used for training.

Tepco published a six- to nine-month plan in April 2011 for dealing with the disabled Fukushima reactors, and updated this several times subsequently. Remediation over the first couple of years proceeded approximately as planned. In August 2011 Tepco announced its general plan for proceeding with removing fuel from the four units, initially from the spent fuel ponds and then from the actual reactors. At the end of 2013 Tepco announced the establishment of an internal entity to focus on measures for decommissioning units 1-6 and dealing with contaminated water. The new company, Fukushima Daiichi Decontamination & Decommissioning Engineering Company, commenced operations in April 2014.

In June 2015 the government revised the decommissioning plan for the second time, though without major change. It clarified milestones to accomplish preventive and multi-layered measures, involving the three principles of removing the source of the contamination, isolating groundwater from the contamination source, and preventing leakage of the contaminated water. It included a new goal of cutting the amount of groundwater flowing into the buildings to less than 100 m ³ per day by April 2016. The schedule for fuel removal from the pond at unit 1 was postponed from late FY17 to FY20, while that for unit 2 was delayed from early FY20 to later the same fiscal year, and that at unit 3 from early FY15 to FY17. Fuel debris removal was to begin in 2021, as before. In September 2017 the government updated the June 2015 decommissioning roadmap, with no changes to the framework, and confirming first removal of fuel debris from unit 1 in 2021. Treatment of all contaminated water accumulated in the reactor buildings was to be completed by 2020.

However, Tepco's latest roadmap shows fuel removal from the pond at unit 1 is now expected FY27-28, and from unit 2 FY24-FY26. For unit 3, fuel removal was completed in February 2021.

Tepco has a website giving updates on decommissioning work and environmental monitoring.

Storage ponds: Debris has been removed from the upper parts of the reactor buildings using large cranes and heavy machinery. Casks to transfer the removed fuel to the central spent fuel facility have been designed and manufactured using existing cask technology.

In July 2012 two unused fuel assemblies were removed from unit 4 pond, and were found to be in good shape, with no deformation or corrosion. Tepco started removal of both fresh and used fuel from the pond in November 2013, 22 assemblies at a time in each cask, with 1331 used and 202 new ones to be moved. This was uneventful, and the task continued through 2014. By 22 December 2014, all 1331 used as well as all 202 new fuel assemblies had been moved in 71 cask shuttles without incident. All of the radioactive used fuel was removed by early November, eliminating a significant radiological hazard on the site. The used fuel went to the central storage pond, from which older assemblies were transferred to dry cask storage. The fresh fuel assemblies are stored in the pool of the undamaged unit 6.

Tepco completed moving fuel from unit 3 in February 2021. It will now focus on 292 used fuel assemblies and 100 new ones from unit 1, and then 587 used assemblies and 28 new ones from unit 2 will be transferred. The NRA has expressed concern about the unit 1 used fuel.

Reactors 1-3 order of work: The locations of leaks from the primary containment vessels (PCVs) and reactor buildings should first be identified using manual and remotely controlled dosimeters, cameras, etc., then the conditions inside the PCVs should be indirectly analysed from the outside via measurements of gamma rays, echo soundings, etc. Any leakage points will be repaired and both reactor vessels (RPVs) and PCVs filled with water sufficient to achieve shielding. Then the vessel heads will be removed. The location of melted fuel and corium will then be established. In particular, the distribution of damaged fuel believed to have flowed out from the RPVs into PCVs will be ascertained, and it will be sampled and analysed. After examination of the inside of the reactors, states of the damaged fuel rods and reactor core internals, sampling will be done and the damaged core material will be removed from the RPVs as well as from the PCVs. Updated plans are on the IRID website.

The four reactors will be completely demolished in 30-40 years - much the same timeframe as for any nuclear plant. As noted above, units 5&6 commenced decommissioning in 2014 and will be used for training.

Earlier, consortia led by both Hitachi-GE and Toshiba submitted proposals to Tepco for decommissioning units 1-4. This would generally involve removing the fuel and then sealing the units for a further decade or two while the activation products in the steel of the reactor pressure vessels decay. They can then be demolished. Removal of the very degraded fuel will be a long process in units 1-3, but will draw on experience at Three Mile Island in the USA.

Tepco has allocated ¥207 billion ($2.5 billion) in its accounts for decommissioning units 1-4. In March 2020, Tepco announced that ¥1.37 trillion ($12.6 billion) would be required for the removal of damaged fuel from units 2&3, with no estimates being made for the fuel in unit 1 which suffered the most damage of the three reactors.

The government has allocated ¥1150 billion ($15 billion) for decontamination in the region, with the promise of more if needed.

The Agency for Natural Resources and Energy (ANRE) calculated that as of January 2017 Tepco needed an estimated ¥22,000 billion ($190 billion), double the original estimate, to implement fuel debris removal, cleanup and for compensation to firms and individuals in Fukushima prefecture. Of this amount, Tepco would pay ¥16 trillion. Other Japanese nuclear operators would pay ¥4 trillion through the Nuclear Damage Compensation and Decommissioning Facilitation Corp (NDF), and the Japanese government would pay ¥2 trillion for cleanup in Fukushima prefecture.

A 12-member international expert team assembled by the IAEA at the request of the Japanese government carried out a fact-finding mission in October 2011 on remediation strategies for contaminated land. Its report focused on the remediation of the affected areas outside of the 20 km restricted area. The team said that it agreed with the prioritization and the general strategy being implemented, but advised the government to focus on actual dose reduction. They should "avoid over-conservatism" which "could not effectively contribute to the reduction of exposure doses" to people. It warned the government against being preoccupied with "contamination concentrations ... rather than dose levels," since this "does not automatically lead to reduction of doses for the public." The report also called on the Japanese authorities to "maintain their focus on remediation activities that bring the best results in reducing the doses to the public." A follow-up mission was carried out in October 2013.

Fukushima Daini plant

The four units at Fukushima Daini were shut down automatically due to the earthquake. The tsunami - here only 9 m high - affected the generators and there was major interruption to cooling due to damaged heat exchangers, so the reactors were almost completely isolated from their ultimate heat sink. Damage to the diesel generators was limited and also the earthquake left one of the external power lines intact, avoiding a station blackout as at Daiichi units 1-4. Staff laid and energized 8.8 km of heavy-duty electric cables in 30 hours to supplement power.

In units 1, 2&4 there were cooling problems still evident on Tuesday 15. Unit 3 was undamaged and continued to 'cold shutdown' status on the 12th, but the other units suffered flooding to pump rooms where the equipment transfers heat from the reactor heat removal circuit to the sea. Pump motors were replaced in less than 30 hours. All units achieved 'cold shutdown' by 16 March, meaning core temperature less than 100 °C at atmospheric pressure (101 kPa), but still requiring some water circulation. The almost complete loss of ultimate heat sink for a day proved a significant challenge, but the cores were kept fully covered.

Radiation monitoring figures remained at low levels, little above background.

There was no technical reason for the Fukushima Daini plant not to restart. However, Tepco in October 2012 said it planned to transfer the fuel from the four reactors to used fuel ponds, and this was done. In February 2015 the prime minister said that restarting the four units was essentially a matter for Tepco to decide. In July 2019 Tepco announced its decision to decommission the four reactors.

International Nuclear Event Scale assessment

Japan's Nuclear & Industrial Safety Agency originally declared the Fukushima Daiichi 1-3 accident as level 5 on the International Nuclear Events Scale (INES) - an accident with wider consequences, the same level as Three Mile Island in 1979. The sequence of events relating to the fuel pond at unit 4 was rated INES level 3 - a serious incident.

However, a month after the tsunami the NSC raised the rating to level 7 for units 1-3 together, 'a major accident', saying that a re-evaluation of early radioactive releases suggested that some 630 PBq of I-131 equivalent had been discharged, mostly in the first week. This then matched the criterion for level 7. In early June NISA increased its estimate of releases to 770 PBq, from about half that, though in August the NSC lowered this estimate to 570 PBq.

For Fukushima Daini, NISA declared INES level 3 for units 1, 2, 4 - each a serious incident.

Accident liability and compensation

Beyond whatever insurance Tepco might carry for its reactors is the question of third party liability for the accident. Japan was not party to any international liability convention but its law generally conforms to them, notably strict and exclusive liability for the operator. Early in 2015 Japan ratified the Convention on Supplementary Compensation for Nuclear Damage (CSC). Two laws governing liability are revised about every ten years: the Law on Compensation for Nuclear Damage and Law on Contract for Liability Insurance for Nuclear Damage. Plant operator liability is exclusive and absolute (regardless of fault), and power plant operators must provide a financial security amount of JPY 120 billion ($1.5 billion) - it was half that to 2010. The government may relieve the operator of liability if it determines that damage results from "a grave natural disaster of an exceptional character" (which it did not do here), and in any case total liability is unlimited.

In mid-April 2011, the first meeting was held of a panel to address compensation for nuclear-related damage. The panel established guidelines for determining the scope of compensation for damage caused by the accident, and to act as an intermediary. It was established within the Ministry of Education, Culture, Sports, Science and Technology (MEXT), and was led by law professor Yoshihisa Nomi of Gakushuin University in Tokyo.

On 11 May 2011, Tepco accepted terms established by the Japanese government for state support to compensate those affected by the accident at the Fukushima Daiichi plant. The scheme included a new state-backed institution to expedite payments to those affected by the Fukushima Daiichi accident. The body receives financial contributions from electric power companies with nuclear power plants in Japan, and from the government through special bonds that can be cashed whenever necessary. The government bonds total JPY 5 trillion ($60 billion). Tepco accepted the conditions imposed on the company as part of the package. That included not setting an upper limit on compensation payments to those affected, making maximum efforts to reduce costs, and an agreement to cooperate with an independent panel set up to investigate its management.

This Nuclear Damage Compensation Facilitation Corporation, established by government and nuclear plant operators, includes representatives from other nuclear generators and also operates as an insurer for the industry, being responsible to have plans in place for any future nuclear accidents. The provision for contributions from other nuclear operators is similar to that in the USA. The government estimates that Tepco will be able to complete its repayments in 10 to 13 years, after which it will revert to a fully private company with no government involvement. Meanwhile it will pay an annual fee for the government support, maintain adequate power supplies and ensure plant safety. Tepco estimated its extra costs for fossil fuels in 2011-12 (April-March) would be about JPY 830 billion ($11 billion).

On 14 June 2011, Japan's cabinet passed the Nuclear Disaster Compensation Bill, and a related budget to fund post-tsunami reconstruction was also passed subsequently.

In September 2011 the Nuclear Damage Compensation Facilitation Corporation started by working with Tepco to compile a business plan for the next decade. This was approved by the Ministry of Economy, Trade and Industry (METI) so that some ¥900 billion ($12 billion) could be released to the company through bonds issued to the Nuclear Damage Facilitation Fund to cover compensation payments to March 2012. The plan also involved Tepco reducing its own costs by ¥2545 billion ($33 billion) over the next ten years, including shedding 7400 jobs. This special business plan was superseded by a more comprehensive business plan in March 2012, involving compensation payments of ¥910 billion ($12 billion) annually. Tepco wanted to include an electricity rate increase of 17% in the plan, to cover the additional annual fuel costs for thermal power generation to make up for lost capacity at idled nuclear power plants.

In February 2012 METI approved a further ¥690 billion ($9 billion) in compensation support from the Nuclear Damage Liability Facilitation Fund, subject to Tepco's business plan giving the government voting rights. In June 2012 shareholders voted to sell the Japanese government 50.11% of Tepco's voting shares and an additional 25.73% with no voting rights, for ¥1 trillion (about $13 billion), paid through the Nuclear Damage Liability Facilitation Fund. This was effected at the end of July, so that Tepco then became government-controlled, at least temporarily. Tepco said it appreciated the chance to "transform to New Tepco".

The government and 12 utilities are contributing funds into the new institution to pay compensation to individuals and businesses claiming damages caused by the accident. It received ¥7 billion ($90 million) in public funds as well as a total of ¥7 billion from 12 nuclear plant operators, the Tepco share of ¥2379 million ($30 million) being the largest. The percentage of utility contributions was fixed in proportion to the power output of their plants, so Kansai Electric Power provided ¥1229 million, followed by ¥660 million by Kyushu Electric Power and ¥622 million by Chubu Electric Power. Japan Nuclear Fuel Ltd., which owns a used nuclear fuel reprocessing plant in Aomori prefecture, provided ¥117 million to the entity. The utility companies also pay annual contributions to the body. Tepco is required to make extra contributions, with the specific amount to be decided later.

In June 2013 Tepco requested a further ¥666 billion ($6.7 billion) in government support through the Nuclear Damage Liability Facilitation Fund, bringing the total amount requested by Tepco to ¥3.79 trillion ($40 billion). The company said that more than half of the request - some ¥370 billion ($4 billion) - resulted from the re-evaluation of the evacuation zone around the damaged plant and a re-examination of the estimated amount "regarding compensation for mental damages, loss or depreciation of valuables such as housing lands and buildings." About ¥43 billion ($430 million) was due to a higher estimate of compensation coming from damages to the agriculture, forestry and fisheries industries, as well as the food processing and distribution industries. This, it said, also resulted from "harmful rumours" about the possible health effects of consuming food products from the region near the damaged power plant. As restrictions on the transport of foodstuffs from the Fukushima area seemed set to continue, an additional ¥240 billion ($2 billion) was included to cover for the further compensation claims resulting from this.

By mid-May 2014, Tepco had paid ¥3808 billion ($40 billion) in compensation, fairly evenly split between businesses and individuals, based on decisions of the Nuclear Damage Compensation Facilitation Corporation, and covered by loans from the NDLF Fund. Some $16 billion of this was distributed evenly among 85,000 evacuees - $188,200 each person including children, as directed early in 2011.

In July 2015 the government approved Tepco's recovery plan, including compensation payments of ¥7075 billion ($57 billion), enabling it to receive ¥950 billion more than the ¥6125 billion estimated in April, according to METI.

As of January 2021 the Fukushima accident evacuees had received ¥9.7 trillion in personal and property compensation.

Earlier, in December 2013 the government raised the upper limit of its financial assistance to Tepco from ¥5 trillion to ¥9 trillion ($86 billion). Early in 2014 the government estimated it would take ¥11 trillion and 40 years to clean up the Fukushima site. The 2013 Japan trade deficit was ¥11.5 trillion.

In September 2019 Tokyo District Court acquitted three former executives - Tsunehisa Katsumata, Ichiro Takekuro and Sakae Muto - with failing to prevent the accident at the company's Fukushima Daiichi plant. The court found all three men not guilty of professional negligence resulting in death and injury and ruled that they could not have foreseen the earthquake and tsunami that led to the meltdown of three of the plant's reactors. In January 2023 the Tokyo High Court upheld the acquittal of the three former executives.

Inquiries and reports: the accident itself and decommissioning

In October 2014 the NRA published its Analysis of the TEPCO Fukushima Daiichi NPS Accident interim report. A provisional translation in English was published in February 2015. This focuses on a number of questions which remained unexplained in the 2012 National Diet Investigation Commission report.

Earlier in May 2011 a team of 18 experts from 12 countries spent a week at the plant on behalf of the International Atomic Energy Agency (IAEA), and that mission's final report was presented to the IAEA Ministerial Conference in Vienna in June. At the IAEA General Conference in 2012 the Director General promised a comprehensive report which would be "an authoritative, factual and balanced assessment, addressing the causes and consequences of the accident as well as the lessons learned." This report on The Fukushima Daiichi Accident was published in August 2015, accompanied by five technical volumes.

In February 2015 the IAEA completed its third review mission (as follow-up to that of late 2013, and involving some 180 experts from 42 IAEA member states and other organizations over two years) and reported on decommissioning to METI. In May 2015 its final report was delivered to member states, and was published in September. It was broadly positive regarding progress since 2013, but said that some challenging issues remain. It contains advisory points on topics such as long-term radioactive waste management, measures concerning contaminated water, and issues related to the removal of used fuel and fuel debris.

The Foreword to the Director General's report in 2015 states: "A major factor that contributed to the accident was the widespread assumption in Japan that its nuclear power plants were so safe that an accident of this magnitude was simply unthinkable. This assumption was accepted by nuclear power plant operators and was not challenged by regulators or by the government. As a result, Japan was not sufficiently prepared for a severe nuclear accident in March 2011." The accident exposed "certain weaknesses" in Japan's regulatory framework, with responsibilities divided among a number of bodies. It also said there were certain weaknesses "in plant design, in emergency preparedness and response arrangement and in planning for the management of a severe accident".

The Director General said: "I am confident that the legacy of the Fukushima Daiichi accident will be a sharper focus on nuclear safety everywhere. I have seen improvements in safety measures and procedures in every nuclear power plant that I have visited. There is widespread recognition that everything humanly possible must be done to ensure that no such accident ever happens again." He added: "This is all the more essential as global use of nuclear power is likely to continue to grow in coming decades." Furthermore, "there can be no grounds for complacency about nuclear safety in any country. Some of the factors that contributed to the Fukushima Daiichi accident were not unique to Japan. Continuous questioning and openness to learning from experience are key to safety culture and are essential for everyone involved in nuclear power."

The Executive Summary includes recommendations, but the following paragraphs indicate some salient points from the actual investigation.

Before the accident, there was a basic assumption in Japan that the design of nuclear power plants and the safety measures that had been put in place were sufficiently robust to withstand external events of low probability and high consequences. Because of the basic assumption that nuclear power plants in Japan were safe, there was a tendency for organizations and their staff not to challenge the level of safety. The reinforced basic assumption among the stakeholders about the robustness of the technical design of nuclear power plants resulted in a situation where safety improvements were not introduced promptly.

Before the accident, the operator had conducted some reassessments of extreme tsunami flood levels, using a consensus based methodology developed in Japan in 2002, which had resulted in values higher than the original design basis estimates. Based on the results, some compensatory measures were taken, but they proved to be insufficient at the time of the accident.

There were no indications that the main safety features of the plant were affected by the vibratory ground motions generated by the earthquake on 11 March 2011. This was due to the conservative approach to earthquake design and construction of nuclear power plants in Japan, resulting in a plant that was provided with sufficient safety margins. However, the original design considerations did not provide comparable safety margins for extreme external flooding events, such as tsunamis.

Despite the efforts of the operators at the Fukushima Daiichi nuclear power plant to maintain control, the reactor cores in units 1-3 overheated, the nuclear fuel melted and the three containment vessels were breached. Hydrogen was released from the reactor pressure vessels, leading to explosions inside the reactor buildings in units 1, 3&4 that damaged structures and equipment and injured personnel. Radionuclides were released from the plant to the atmosphere and were deposited on land and on the ocean. There were also direct releases into the sea.

Venting of the containment was necessary to relieve pressure and prevent its failure. The operators were able to vent units 1 and 3 to reduce the pressure in the primary containment vessels. However, this resulted in radioactive releases to the environment. Even though the containment vents for units 1 and 3 were opened, the primary containment vessels for units 1 and 3 eventually failed. Containment venting for unit 2 was not successful, and the containment failed, resulting in radioactive releases.

People within a radius of 20 km of the site and in other designated areas were evacuated, and those within a radius of 20-30 km were instructed to shelter before later being advised to voluntarily evacuate. Restrictions were placed on the distribution and consumption of food and the consumption of drinking water. Many people are still living outside the areas from which they were evacuated.

No early radiation induced health effects were observed among workers or members of the public that could be attributed to the accident.

Earlier reports 2011-2012

Early in June 2011 the independent Investigation Committee on the Accident at the Fukushima Nuclear Power Stations ( ICANPS), a panel of ten experts, mostly academics and appointed by the Japanese cabinet, began meeting. It had two technological advisers. An initial report was published in December 2011 and a final report in July 2012. The panel set up four teams to undertake investigations on the causes of the accident and ensuing damage and on measures to prevent the further spread of damage caused by the accident, but not to pursue the question of responsibility for the accident.

The national Diet later set up the legally-constituted Nuclear Accident Independent Investigation Commission ( NAIIC, or National Diet Investigation Commission) of ten members which started its work in December 2011. One of the purposes of NAIIC was to provide suggestions including the "re-examination of an optimal administrative organization" for nuclear safety regulation based on its investigation of the accident. The NAIIC reported in July 2012, harshly criticizing the government, the plant operator and the country's national culture. After conducting 900 hours of public hearings and interviews with more than 1100 people and visiting several nuclear power plants, the commission's report concluded that the accident was a "manmade disaster," the result of "collusion between the government, the regulators and Tokyo Electric Power Co." It said the "root causes were the organizational and regulatory systems that supported faulty rationales for decisions and actions." The NAIIC criticized the regulator for insufficiently maintaining independence from the industry in developing and enforcing safety regulations, the government for inadequate emergency preparedness and management, and Tepco for its poor governance and lack of safety culture. The report called for fundamental changes across the industry, including the government and regulators, to increase openness, trustworthiness and focus on protecting public health and safety.

The NAIIC Chairman wrote: "What must be admitted - very painfully - is that this was a disaster 'Made in Japan.' Its fundamental causes are to be found in the ingrained conventions of Japanese culture: our reflexive obedience; our reluctance to question authority; our devotion to 'sticking with the programme'; our groupism; and our insularity." The mindset of the government and industry led the country to avoid learning the lessons of the previous major nuclear accidents at Three Mile Island and Chernobyl. "The consequences of negligence at Fukushima stand out as catastrophic, but the mindset that supported it can be found across Japan. In recognizing that fact, each of us (every Japanese citizen) should reflect on our responsibility as individuals in a democratic society."

The NAIIC reported that Tepco had been aware since 2006 that Fukushima Daiichi could face a station blackout if flooded, as well as the potential loss of ultimate heat sink in the event of a major tsunami. However, the regulator, NISA, gave no instruction to the company to prepare for severe flooding, and even told all nuclear operators that it was not necessary to plan for station blackout. During the initial response to the tsunami, this lack of readiness for station blackout was compounded by a lack of planning and training for severe accident mitigation. Plans and procedures for venting and manual operation of emergency cooling were incomplete and their implementation in emergency circumstances proved very difficult as a result. NISA was also criticized for its "negligence and failure over the years" to prepare for a nuclear accident in terms of public information and evacuation, with previous governments equally culpable. Then Tepco's difficulty in mitigation was compounded by government interference which undermined NISA.

Earlier, on 7 June 2011 the government submitted a 750-page report to the IAEA compiled by the nuclear emergency task force, acknowledging reactor design inadequacies and systemic shortcomings. It said: "In light of the lessons learned from the accident, Japan has recognized that a fundamental revision of its nuclear safety preparedness and response is inevitable."

On 11 September 2011 a second report was issued by the government and submitted to the IAEA, summarising both onsite work and progress and offsite responses. It contained further analysis of the earthquake and tsunami, the initial responses to manage and cool the reactors, the state of spent fuel ponds and the state of reactor pressure vessels. It also summarised radioactive releases and their effects.

Meanwhile a July 2011 report from MIT's Centre for Advanced Nuclear Energy Systems provided a useful series of observations, questions raised, and suggestions. Its Appendix has some constructive comment on radiation exposure and balancing the costs of dose avoidance in circumstances of environmental contamination.

In November 2011 the US Institute of Nuclear Power Operations (INPO) released its Special Report on the Nuclear Accident at the Fukushima Daiichi Nuclear Power Station, with timeline. This 97-page report gives a detailed account of events.

Also in November 2011 the Japan Nuclear Technology Institute published a 280-page report on the accident, with proposals to be addressed in the future.

On 2 December 2011 Tepco released its interim investigation report on the accident (in Japanese).

The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) undertook a 12-month study on the magnitude of radioactive releases to the atmosphere and ocean, and the range of radiation doses received by the public and workers. A follow-up white paper was published in 2016.

An analysis by the Carnegie Endowment in March 2012 said that if best practice from other countries had been adopted by Tepco and NISA at Fukushima, the serious accident would not have happened, underlining the need for greater international regulatory collaboration.

In April 2012 the US Electric Power Research Institute (EPRI) published Fukushima Daiichi Accident - Technical Causal Factor Analysis, which identified the root cause beyond the flooding and its effects as a failure to consider the possibility of the rupture of combinations of geological fault segments in the vicinity of the plant.

Inquiries and reports: radiation effects

A preliminary report from the World Health Organization (WHO) in May 2012 estimated the radiation doses that residents of Japan outside the evacuated areas received in the year following the accident. The report's headline conclusion is that most people in Fukushima prefecture would have received a radiation dose of between 1 and 10 mSv during the first year after the accident. This compares with levels of about 2.4 mSv they would have received from unavoidable natural sources. In two places the doses were higher - between 10 and 50 mSv, still below any harmful level. Almost all were "below the internationally-agreed reference level for the public exposure due to radon in dwellings" (about 10 mSv/yr).

The UN Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) in May 2012 reported that despite skin contamination of several workers, no clinically-observable effects have been reported and there is no evidence of acute radiation injury in any of the 20,115 workers who participated in Tepco's efforts to mitigate the accident at the plant. Eighteen UNSCEAR member states provided 72 experts for the assessment. UNSCEAR also surveyed Fukushima prefecture to compare its data with Japanese measurements of exposures of some 2 million people living there at the time of the accident.

The results of UNSCEAR's 12-month study on the magnitude of radioactive releases to the atmosphere and ocean, and the range of radiation doses received by the public and workers were announced in May 2013 are reported above in the subsection above on Radiation exposure.

UNSCEAR's April 2014 report on radiation effects concluded that the rates of cancer or hereditary diseases were unlikely to show any discernible rise in affected areas because the radiation doses people received were too low. People were promptly evacuated from the vicinity of the nuclear power plant, and later from a neighbouring area where radionuclides had accumulated. This action reduced their radiation exposure by a factor of ten, to levels that were "low or very low." Overall, people in Fukushima are expected on average to receive less than 10 mSv due to the accident over their whole lifetime, compared with the 170 mSv lifetime dose from natural background radiation that people in Japan typically receive. "The most important health effect is on mental and social well-being, related to the enormous impact of the earthquake, tsunami and nuclear accident, and the fear and stigma related to the perceived risk of exposure to radiation." UNSCEAR's follow-up white paper in October 2015 said that none of the new information appraised after the 2013 report "materially affected the main findings in, or challenged the major assumptions of, the 2013 Fukushima report."

UNSCEAR's update of its 2013 report, published in March 2021, broadly confirms the major findings and conclusions of the 2013 report. It concludes: "The Committee's revised estimates of dose are such that future radiation-associated health effects are unlikely to be discernible."

In October 2013 a 16-member IAEA mission visited at government request and reported on remediation and decontamination in particular. Its preliminary report said that decontamination efforts were commendable but driven by unrealistic targets.

'Stress tests' on Japanese reactors and new regulatory authority

The government ordered nuclear risk and safety reassessments - so-called 'stress tests' - based on those in the EU for all Japan's nuclear reactors except Fukushima's before they restart following any shutdown, including for routine checks. These were in two stages, and are described in the Japan Nuclear Power information page.

The government then created the separate Nuclear Regulatory Agency (NRA) under the authority of the Environment Ministry and combining the roles of NISA and the NSC, commissioned in September 2012. The new Nuclear Regulatory Commission (NRC) replaced the NSC and will review the effectiveness of the NRA and be responsible for the investigation of nuclear accidents.

Notes & references

General sources

Tepco
NISA
IAEA
METI
JAIF
NSC
Acton J.M. & Hibbs M, Why Fukushima was preventable, March 2012 Carnegie Paper
INPO 11-005 Addendum, Aug 2012, Lessons learned from the Nuclear Accident at Fukushima Daiichi Nuclear Power Station
Government's Decision on Addressing the Contaminated Water Issue at TEPCO's Fukushima Daiichi NPS, 3 Sept 2013, on Ministry of Foreign Affairs website
K. Tateiwa, Decommissioning Fukushima Daiichi NPS, January 2014
UNSCEAR webpage on The Fukushima-Daiichi nuclear power plant accident
IAEA Report by the Director General on The Fukushima Daiichi Accident, STI/PUB/1710 (ISBN:978-92-0-107015-9), August 2015
A. Komori, Current status and the future of Fukushima Daiichi NP station, World Nuclear Association 2015 Symposium presentation
OECD Nuclear Energy Agency, Fukushima Daiichi Nuclear Power Plant Accident, Ten Years On: Progress, Lessons and Challenges, 2021

Appendices

Fukushima: Radiation Exposure
Fukushima: Reactor Background
Earthquakes and Seismic Protection for Japanese Nuclear Power Plants

Japan: Nuclear Power
Chernobyl Accident
Nuclear Energy and Sustainable Development
Nuclear Power in the World Today

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This information paper describes in detail the causes of the nuclear accident at Fukushima Daiichi in March 2011 and the actions taken since.

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The Israel Defense Forces are issuing evacuation orders to the people of Gaza, people were either walking or on donkey carts as they were leaving Deir al-Balah, the central Gazan city. Some people fortunately had private cars filled with their belongings.

84% of Gaza is currently covered by evacuation orders throughout the past month according to the UNRWA, the humanitarian zone has also been reduced by 38% by the IDF.

Because of the humanitarian zone being reduced, that zone only makes up 10% of Gaza now. Lots of Gazans had to evacuate over and over again, and some didn't even know where to go but they had to evacuate anyways. Food and health is a big problem as well.

This article is related to geography.

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Thousands of Gazans are on the move again after the Israel Defense Forces reissued evacuation orders for parts of the southern strip, according to video shot by CNN.

People were walking or on donkey carts as they left areas near the central Gazan city of Deir al-Balah.

Some were in private cars, loaded with their belongings, including mattresses and blankets, water and gas bottles.

The streets appear littered with leaflets dropped by the IDF reiterating the order to evacuate.

According to UNRWA, the United Nations' agency for Palestinian refugees, about 84 per cent of Gaza is now covered by multiple evacuation orders issued over the past month.

By contrast, a CNN analysis shows that in the past month, the IDF has reduced the humanitarian zone in Gaza by 38 per cent.

That zone now amounts to 39 square kilometres - just over 10 per cent of Gaza's total area.

Amid the latest evacuation, people swarmed onto a UN truck carrying food aid, carrying off small bags of aid.

For many, they've had to evacuate time and time again - leaving them in a constant state of displacement, uncertainty and the sense there is nowhere left to flee.

"There is bombardment, shooting, and quadcopters since this morning in the east of Deir al-Balah, so we are forced to flee," one of the evacuees, Muhammad Awad, told CNN.

"People go to the unknown. They have no idea. There was a statement ordering people to evacuate."

Um Alaa, sitting on a cart, said it was the fourth time she has had to evacuate since October last year.

"We don't know where to go. We are going to look for a spot away from this dangerous place," she said.

"The whole of Gaza has become dangerous."

There was panic among some as to what might come next.

"There are no longer places to go. There was only Deir al-Balah, and now they are asking us to evacuate Deir al-Balah," an elderly man said.

"I am afraid that tomorrow they will confine all of us on the seashore of Deir al-Balah, then exterminate all of us.

"After so many displacements, we no longer have the strength to evacuate yet another time."

The Deir Al-Balah evacuation has also caused complications in the supposed humanitarian zones of Gaza.

The UN Office for the Coordination of Humanitarian Affairs (OCHA) reported that parts of a major road - crucial for humanitarian missions going from south to north - were caught up in the order, making it "nearly impossible" for aid workers to travel along the route.

Um Ismail, a woman with small children, said people were defenseless.

"Why are they fighting us?" she said.

"We are not Hamas, we are simply people staying put in our homes. They displaced us not once, but 10 times. Why? What have we done?"

A woman in the back seat of a car exclaimed: "Do you want to know what's happening - ask Hamas and the Israelis if you want to know what's happening to us."

Her family said it was their second displacement. For a very few, it was the first time since the conflict began that they'd had to move.

One man was crying as he drove a car packed with women and children. "I have no idea where we are heading to," he said. "Anywhere we can stay. God help us. This is the first time I am being displaced."

But for Umm Said it was the seventh move in as many months.

"I don't know where I am heading to. They said leave, we left. We have no idea," she said. "Every time we find a place and settle down, they say go back. And here we are. I have taken some flour for the children, what else can I take with me?"

Abu Muhammad Hajjaj, a resident of Gaza City, had been displaced from the Shujaiya neighborhood.

"We came here to our relatives in Deir al-Balah. Today, they have asked us to evacuate. We don't have any resources; we don't even have a tent to live in. We don't have money to pay for a car. We don't know where to go," he told CNN.

"People are crying and complaining of everything: disease, hunger, poverty, lack of hygiene, lack of medicine. You search in all of Gaza for paracetamol for a headache and you can't find it."

Hajjaj also appealed to the international community, including the UN Security Council, to "find us a solution."

"We don't have money. We don't have tents. We have nothing," he said. "We are not living in our own homes. We are on the street. They cannot keep on telling us to evacuate from here and there. This is not a way to live."

CONTACT US

Passenger and pilot walk away from light plane crash in Sydney park

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Thousands flee southern Gaza after Israeli military's evacuation order

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Thousands of Gazans are on the move again after the Israel Defense Forces reissued evacuation orders for pa...

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This article is about the Marine pollution, it focuses on different types of pollution such as chemical pollution, light pollution, noise pollution, and plastic pollution.

The article explains that the ocean covers 70% of the Earth and before 1972 humans around the world already started to throw trash such as chemicals, radioactive wastes, sewage wastes and etc into the ocean.

It explains how bad Marine pollution is. For example trash/waste can harm animals/creatures below the ocean like how plastic bits can accidentally get eaten or sucked in by turtles which can cause them to get injured or even death.

The pollution is really hard to remove, it might even take centuries to be fully removed.

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THE OCEANS ARE so vast and deep that until fairly recently, it was widely assumed that no matter how much trash and chemicals humans dumped into them, the effects would be negligible.

Today, we need look no further than the New Jersey-size dead zone that forms each summer in the Gulf of Mexico, or the thousand-mile-wide belt of plastic trash in the northern Pacific Ocean to see that this early "policy" placed a once flourishing ocean ecosystem on the brink of collapse.

Many "flavors" of marine pollution

Ocean water covers more than 70 percent of the Earth, and only in recent decades have we begun to understand how humans impact this watery habitat. Marine pollution, as distinct from overall water pollution, focuses on human-created products that enter the ocean.

Before 1972, humans around the word spewed trash, sewage sludge, and chemical, industrial, and radioactive wastes into the ocean with impunity. Millions of tons of heavy metals and chemical contaminants, along with thousands of containers of radioactive waste, were purposely thrown into the ocean.

The London Convention, ratified in 1975 by the United States, was the first international agreement to spell out better protection for the marine environment. The agreement implemented regulatory programs and prohibited the disposal of hazardous materials at sea. An updated agreement, the London Protocol, went into effect in 2006, more specifically banning all wastes and materials except for a short list of items, like leftover materials from dredging.

Many of these pollutants sink to the ocean's depths or float far distances from their original source, where they are consumed by small marine organisms and introduced into the global food chain. Marine pollution encompasses many types of pollution that disrupt the marine ecosystem, including chemical, light, noise, and plastic pollution.

Chemical pollution

Chemical pollution is the introduction of harmful contaminants. Common man-made pollutants that reach the ocean include pesticides, herbicides, fertilizers, detergents, oil, industrial chemicals, and sewage.

Many ocean pollutants are released into the environment far upstream from coastlines. Nutrient-packed fertilizers applied to farmland, for example, often end up in local streams and are eventually deposited into estuaries and bays. These excess nutrients trigger massive blooms of algae that rob the water of oxygen, leaving dead zones where few marine organisms can live. Some chemical pollutants climb high into the food webs-like DDT, the insecticide that placed the bald eagle on the United States Fish and Wildlife's endangered species list.

Scientists are starting to better understand how specific pollutants, leached into the ocean from other materials, affect marine wildlife. PFAS, a chemical incorporated into many household products, accumulates in human and marine mammal blood. Even pharmaceuticals ingested by humans, but not fully processed by our bodies, end up in aquatic food webs.

Light pollution

Since the invention of the lightbulb, light has spread across the globe, reaching almost every ecosystem. Often thought of as a terrestrial problem, scientists are starting to understand how artificial light at night affects many marine organisms.

Light pollution penetrates under the water, creating a vastly different world for fish living in shallow reefs near urban environments. Light disrupts the normal cues associated with circadian rhythms, to which species have evolved timing of migration, reproducing, and feeding. Artificial light at night can make it easier for predators to find smaller fish prey and can affect breeding in reef fish.

Noise pollution

Pollution is not always visible. In large bodies of water, sound waves can carry undiminished for miles. The increased presence of loud or persistent sounds from ships, sonar devices, and oil rigs disrupts natural noises in the marine environment.

For many marine mammals, like whales and dolphins, low visibility and large distances make non-visual underwater communication critical. Toothed whales use echolocation-emitting sounds that reflect off surfaces-to help them "see" in the ocean. Unnatural noises interrupt communication, disrupting migration, communication, hunting, and reproduction patterns for many marine animals.

Plastic pollution

Plastic pollution seeps into the ocean through run-off and even purposeful dumping. The amount of plastic in the Atlantic Ocean has tripled since the 1960s. The garbage patch floating in the Pacific Ocean, almost 620,000 square miles- twice the size of Texas -is a powerful image of our plastic problem.

A huge culprit is single-use plastics, used once before tossed into the trash or directly into the ocean. These single-use items are accidentally consumed by many marine mammals. Plastic bags resemble jellyfish, a common food for sea turtles, while some seabirds eat plastic because it releases a chemical that makes it smell like its natural food. Discarded fishing nets drift for years, ensnaring fish and mammals.

Bits of plastic swirl throughout the water column, even sinking to the deepest depths of the ocean. Scientists found plastic fibers in corals in the Atlantic Ocean-and more concerning, they found that the corals readily ate plastic over food. Dying marine mammals, washing up on shore, also contain plastic inside their stomachs.

Is there a "fix" to marine pollution?

Many national laws, as well as international agreements, now forbid dumping of harmful materials into the ocean, although enforcing these regulations remains a challenge.

Many pollutants still persist in the environment, difficult to fully remove. Chemical pollutants often cannot be broken down for long periods of time, or they increase in concentration as they move up the food web. Because plastic is thought to take hundreds of years to break down, it poses a threat to the marine environment for centuries.

Isolated efforts to restore estuaries and bays have met with some success, but pollution gets trapped in marine sediment and makes complete clean-ups nearly impossible.

Moving forward, encouraging recycling and reuse can minimize plastic pollution. Dampening unnecessary lights at night can limit light pollution. And encouraging responsible chemical-use through consumer and political actions can protect the environment for the future.

National Geographic is committed to reducing plastics pollution. Learn more about our non-profit activities at natgeo.org/plastics. Learn what you can do to reduce your own single-use plastics, and take your pledge.

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THE OCEANS ARE so vast and deep that until fairly recently, it was widely assumed that no matter how much trash and chemicals humans dumped into them, the effects would be negligible.

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This article is about what is tornado, how many people dead because of tornado and how to save urself if u see tornado.

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Zion Kuo 8YP                             Chernobyl Accident 1986

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Zion Kuo 8YP                             Chernobyl Accident 1986

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The accident at the Chornobyl nuclear reactor that occurred on 26 April 1986 was the most serious accident ever to occur in the nuclear power industry. The reactor was destroyed in the accident and considerable amounts of radioactive material were released to the environment. The accident caused the deaths, within a few weeks, of 30 workers and radiation injuries to over a hundred others. In response, the authorities evacuated, in 1986, about 115,000 people from areas surrounding the reactor and subsequently relocated, after 1986, about 220,000 people from Belarus, the Russian Federation and Ukraine. The accident caused serious social and psychological disruption in the lives of those affected and vast economic losses over the entire region. Large areas of the three countries were contaminated with radioactive materials, and radionuclides from the Chornobyl release were measurable in all countries of the northern hemisphere.

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The Hong Kong Observatory issued an amber rainstorm warning at lunchtime on Monday, as the city was hit by widespread heavy showers.

They also warned of a flash flood

{this is what the forecaster said}

“Showers and thunderstorms associated with a broad trough of low pressure are affecting the coast of Guangdong and the northern part of the South China Sea,” the Observatory said.

“Showers will be heavy at times with squally thunderstorms in the next couple of days.”

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Hong Kong Observatory issues amber rainstorm warning after city hit with heavy showers

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Forecaster also warned of flash floods but said it should get sunny on Friday.

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This article is about...THE BIGGEST EARTHQUAKE IN USA

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The 1964 Alaskan earthquake, also known as the Great Alaskan earthquake and Good Friday earthquake, occurred at 5:36 PM AKST on Good Friday, March 27, 1964.[2] Across south-central Alaska, ground fissures, collapsing structures, and tsunamis resulting from the earthquake caused about 131 deaths.[3]

Lasting four minutes and thirty-eight seconds, the magnitude 9.2–9.3 megathrust earthquake remains the most powerful earthquake ever recorded in North America,[2]

A lot of people died from earthquake and their house have been destroyed house

In Prince William Sound, Port Valdez suffered a massive underwater landslide, resulting in the deaths of 32 peoples

The earthquake is the biggest earthquake in history.

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The biggest earthquake ever recorded, of magnitude 9.5, happened in 1960 in Chile.

also known as the Great Chilean Earthquake

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In this article, the writer talks about a deadly disease that affects the cats animals even makes them into death.When the writer took her cat for a walk, they met a tiger with some problems on it suddenly. After taking it back for a body check, Emerging Infectious Diseases show that the mountain lion had a fatal neurologic syndrome called staggering disease.

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A deadly disease that affects cats big and small found in U.S.

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The virus inflamed a cougar’s brain and tissue in Colorado, though it’s unclear how long the disease has been on the continent or how prevalent it is.

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This article is about climate change. It focuses on one-term shifts in temperatures and weather patterns. The main reason that our earth have climate change is because people excessive of earth energy。

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A magnitude 7.3 earthquake was recorded on Taiwan’s southeast coast on Wednesday, with more than 100 Hongkongers reporting feeling tremors, said the Hong Kong Observatory.

The weather watchdog said the quake hit at 7.58 am about 15km southeast of the Taiwanese county of Hualien and had an epicenter spanning 10km.

香港天文台稱，台灣東南沿海週三發生里氏7.3級地震，超過100名香港人報告感到震顫。

氣象監督機構表示，地震發生在上午 7 點 58 分，距離台灣花蓮縣東南方約 15 公里，震央長達 10 公里。

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"Forest loss intensifies climate change by increasing temperatures and cloud level, which leads to decrease of water."

In August 19, 2024, researchers report that deforestation during the last two decades led to a higher warming and cloud level rise than that caused by climate change, which threatens biodiversity and water supply in African montane forests.

Montane forests are often cloudy, wet, cold, and occur on isolated mountains in Africa. They are rich in biodiversity and act as water towers by trapping water from fog and clouds, providing high quality fresh water for millions of people in the lowlands of Africa.

So in the last two decades, as much as 18 percent of Africa's montane forests were lost due to deforestation, which resulted in a warming and cloud level rise two times higher than that caused by climate change. Research resulted that air temperature has increased by 1,4 centigrades, while cloud level has risen by approximately 230 meters during the last 20 years.

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This article is about Global Warming. Global warming is the long-term heating of Earth's surface observed since the pre-industrial period (between 1850 and 1900) due to human activities, primarily fossil fuel burning, which increases heat-trapping greenhouse gas levels in Earth's atmosphere. This term is not interchangeable with the term "climate change.