Nuclear safety
Encyclopedia
Nuclear safety covers the actions taken to prevent nuclear and radiation accidents
Nuclear and radiation accidents
A nuclear and radiation accident is defined by the International Atomic Energy Agency as "an event that has led to significant consequences to people, the environment or the facility...

 or to limit their consequences. This covers nuclear power plants as well as all other nuclear facilities, the transportation of nuclear materials, and the use and storage of nuclear materials for medical, power, industry, and military uses.

The nuclear power industry has improved the safety and performance of reactors, and has proposed new safer (but generally untested) reactor designs but there is no guarantee that the reactors will be designed, built and operated correctly. Mistakes do occur and the designers of reactors at Fukushima
Timeline of the Fukushima nuclear accidents
For the timelines of the nuclear accidents at Fukushima Daiichi and Fukushima Daini after the 2011 Tohoku earthquake and tsunami, see:* Timeline of the Fukushima I nuclear accidents* Timeline of the Fukushima II nuclear accidents...

 in Japan did not anticipate that a tsunami generated by an earthquake would disable the backup systems that were supposed to stabilize the reactor after the earthquake. According to UBS AG, the Fukushima I nuclear accidents have cast doubt on whether even an advanced economy like Japan can master nuclear safety. Catastrophic scenarios involving terrorist attacks are also conceivable.

An interdisciplinary team from MIT have estimated that given the expected growth of nuclear power from 2005 – 2055, at least four serious nuclear accidents would be expected in that period. To date, there have been five serious accidents (core damage) in the world since 1970 (one at Three Mile Island
Three Mile Island accident
The Three Mile Island accident was a core meltdown in Unit 2 of the Three Mile Island Nuclear Generating Station in Dauphin County, Pennsylvania near Harrisburg, United States in 1979....

 in 1979; one at Chernobyl
Chernobyl
Chernobyl or Chornobyl is an abandoned city in northern Ukraine, in Kiev Oblast, near the border with Belarus. The city had been the administrative centre of the Chernobyl Raion since 1932....

 in 1986; and three at Fukushima-Daiichi
Fukushima Daiichi nuclear disaster
The is a series of equipment failures, nuclear meltdowns, and releases of radioactive materials at the Fukushima I Nuclear Power Plant, following the Tōhoku earthquake and tsunami on 11 March 2011. The plant comprises six separate boiling water reactors originally designed by General Electric ,...

 in 2011), corresponding to the beginning of the operation of generation II reactor
Generation II reactor
A generation II reactor is a design classification for a nuclear reactor, and refers to the class of commercial reactors built up to the end of the 1990s...

s. This leads to on average one serious accident happening every eight years worldwide.

Nuclear weapon
Nuclear weapon
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from relatively small amounts of matter. The first fission bomb test released the same amount...

 safety, as well as the safety of military research involving nuclear materials, is generally handled by agencies different from those that oversee civilian safety, for various reasons, including secrecy.

Agencies

Internationally the International Atomic Energy Agency
International Atomic Energy Agency
The International Atomic Energy Agency is an international organization that seeks to promote the peaceful use of nuclear energy, and to inhibit its use for any military purpose, including nuclear weapons. The IAEA was established as an autonomous organization on 29 July 1957...

 "works with its Member States and multiple partners worldwide to promote safe, secure and peaceful nuclear technologies." Some scientists say that the 2011 Japanese nuclear accidents
2011 Japanese nuclear accidents
This is a list of articles describing aspects of the nuclear shut-downs, failures, and nuclear meltdowns triggered by the 2011 Tōhoku earthquake and tsunami.-Fukushima nuclear power plants:* Fukushima I Nuclear Power Plant...

 have revealed that the nuclear industry lacks sufficient oversight, leading to renewed calls to redefine the mandate of the IAEA so that it can better police nuclear power plants worldwide. There are several problems with the IAEA says Najmedin Meshkati of University of Southern California:

It recommends safety standards, but member states are not required to comply; it promotes nuclear energy, but it also monitors nuclear use; it is the sole global organization overseeing the nuclear energy industry, yet it is also weighed down by checking compliance with the Nuclear Non-Proliferation Treaty (NPT).


Many nations utilizing nuclear power
Nuclear power
Nuclear power is the use of sustained nuclear fission to generate heat and electricity. Nuclear power plants provide about 6% of the world's energy and 13–14% of the world's electricity, with the U.S., France, and Japan together accounting for about 50% of nuclear generated electricity...

 have special institutions overseeing and regulating nuclear safety. Civilian nuclear safety in the U.S. is regulated by the Nuclear Regulatory Commission
Nuclear Regulatory Commission
The Nuclear Regulatory Commission is an independent agency of the United States government that was established by the Energy Reorganization Act of 1974 from the United States Atomic Energy Commission, and was first opened January 19, 1975...

 (NRC). The safety of nuclear plants and materials controlled by the U.S. government for research, weapons production, and those powering naval vessels is not governed by the NRC. In the UK nuclear safety is regulated by the Office for Nuclear Regulation
Office for Nuclear Regulation
The Office for Nuclear Regulation is the regulator for the civil nuclear industry in the United Kingdom. Created on 1 April 2011, the ONR is formed from the merger of the Health and Safety Executive's Nuclear Directorate and, from 1 June 2011, the Department for Transport's...

 (ONR) and the Defence Nuclear Safety Regulator (DNSR). The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) is the Federal Government body that monitors and identifies solar radiation and nuclear radiation risks in Australia. It is the main body dealing with ionizing and non-ionizing radiation and publishes material regarding radiation protection.

Other agencies include:
  • Autorité de sûreté nucléaire
    Autorité de sûreté nucléaire
    The Autorité de sûreté nucléaire is an independent French administrative authority set up by law 2006-686 of 13 June 2006 concerning nuclear transparency and safety. Its task, on behalf of the State, is to regulate nuclear safety and radiation protection in order to protect workers, patients, the...

  • Canadian Nuclear Safety Commission
    Canadian Nuclear Safety Commission
    The Canadian Nuclear Safety Commission , previously known as the Atomic Energy Control Board , is the governmental nuclear power and materials watchdog in Canada...

  • Radiological Protection Institute of Ireland
    Radiological Protection Institute of Ireland
    The Radiological Protection Institute of Ireland is an independent public body in the Republic of Ireland under the ageis of the Department of Environment, Heritage and Local Government.The RPII was established in 1992 under the , which conferred on the RPII a broad remit in relation to...

  • Federal Atomic Energy Agency
    Federal Atomic Energy Agency
    Rosatom Nuclear Energy State Corporation , is a State Corporation in Russia, the regulatory body of the Russian nuclear complex. It is headquartered in Moscow.- History :...

     in Russia
    Russia
    Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

  • Kernfysische dienst
    Kernfysische dienst
    The Kernfysische dienst is the Dutch nuclear regulatory organisation. It is a part of the ministry of Ministry of Infrastructure and the Environment ....

    , (NL)
  • Pakistan Nuclear Regulatory Authority
    Pakistan Nuclear Regulatory Authority
    The Pakistan Nuclear Regulatory Authority , is the Pakistan's federal government agency which is based in Islamabad, Pakistan. The Pakistan Nuclear Regulatory Authority was established to ensure safe operation of nuclear facilities and to protect radiation workers, general public and the...

  • Bundesamt für Strahlenschutz
    Bundesamt für Strahlenschutz
    The Bundesamt für Strahlenschutz is the German Federal Authority for Radiation Protection. The BfS was established in November 1989, the headquarter is located in Salzgitter, with branch offices in Berlin, Bonn, Freiburg, Gorleben, Oberschleißheim and Rendsburg. It has 708 employees and an annual...

    , (DE)
  • Atomic Energy Regulatory Board
    Atomic Energy Regulatory Board
    The Atomic Energy Regulatory Board was constituted on November 15, 1983 by the President of India by exercising the powers conferred by Section 27 of the Atomic Energy Act, 1962 to carry out certain regulatory and safety functions under the Act...

     (India)

Hazards of nuclear material

The world's nuclear fleet creates about 10,000 metric tons of high-level spent nuclear fuel each year. High-level radioactive waste management concerns management and disposal of highly radioactive
Radioactive decay
Radioactive decay is the process by which an atomic nucleus of an unstable atom loses energy by emitting ionizing particles . The emission is spontaneous, in that the atom decays without any physical interaction with another particle from outside the atom...

 materials created during production of nuclear power. The technical issues in accomplishing this are daunting, due to the extremely long periods radioactive waste
Radioactive waste
Radioactive wastes are wastes that contain radioactive material. Radioactive wastes are usually by-products of nuclear power generation and other applications of nuclear fission or nuclear technology, such as research and medicine...

s remain deadly to living organisms. Of particular concern are two long-lived fission product
Long-lived fission product
Long-lived fission products are radioactive materials with a long half-life produced by nuclear fission.-Evolution of radioactivity in nuclear waste:...

s, Technetium-99
Technetium-99
Technetium-99 is an isotope of technetium which decays with a half-life of 211,000 years to stable ruthenium-99, emitting soft beta rays, but no gamma rays....

 (half-life 220,000 years) and Iodine-129
Iodine-129
Iodine-129 is long-lived radioisotope of iodine which occurs naturally, but also is of special interest in the monitoring and effects of man-made nuclear fission decay products, where it serves as both tracer and potential radiological contaminant....

 (half-life 15.7 million years), which dominate spent nuclear fuel radioactivity after a few thousand years. The most troublesome transuranic element
Transuranium element
In chemistry, transuranium elements are the chemical elements with atomic numbers greater than 92...

s in spent fuel are Neptunium-237
Isotopes of neptunium
Neptunium is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes...

 (half-life two million years) and Plutonium-239
Plutonium-239
Plutonium-239 is an isotope of plutonium. Plutonium-239 is the primary fissile isotope used for the production of nuclear weapons, although uranium-235 has also been used and is currently the secondary isotope. Plutonium-239 is also one of the three main isotopes demonstrated usable as fuel in...

 (half-life 24,000 years). Consequently, high-level radioactive waste requires sophisticated treatment and management to successfully isolate it from the biosphere
Biosphere
The biosphere is the global sum of all ecosystems. It can also be called the zone of life on Earth, a closed and self-regulating system...

. This usually necessitates treatment, followed by a long-term management strategy involving permanent storage, disposal or transformation of the waste into a non-toxic form.

Governments around the world are considering a range of waste management and disposal options, usually involving deep-geologic placement, although there has been limited progress toward implementing long-term waste management solutions. This is partly because the timeframes in question when dealing with radioactive waste
Radioactive waste
Radioactive wastes are wastes that contain radioactive material. Radioactive wastes are usually by-products of nuclear power generation and other applications of nuclear fission or nuclear technology, such as research and medicine...

 range from 10,000 to millions of years, according to studies based on the effect of estimated radiation doses.

New nuclear technologies

Nuclear proponents have tried bolster public support by offering newer, safer, reactor designs. These designs include those that incorporate passive safety and Small Modular Reactors. While these reactor designs "are intended to inspire trust, they may have an unintended effect: creating distrust of older reactors that lack the touted safety features".

The next nuclear plants to be built will likely be Generation III or III+ designs
Generation III reactor
A generation III reactor is a development of any of the generation II nuclear reactor designs incorporating evolutionary improvements in design developed during the lifetime of the generation II reactor designs...

, and a few such are already in operation in Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

. Generation IV reactor
Generation IV reactor
Generation IV reactors are a set of theoretical nuclear reactor designs currently being researched. Most of these designs are generally not expected to be available for commercial construction before 2030...

s would have even greater improvements in safety. These new designs are expected to be passively safe
Passive nuclear safety
Passive nuclear safety is a safety feature of a nuclear reactor that does not require operator actions or electronic feedback in order to shut down safely in the event of a particular type of emergency...

 or nearly so, and perhaps even inherently safe (as in the PBMR designs).

Some improvements made (not all in all designs) are having three sets of emergency diesel generators and associated emergency core cooling systems rather than just one pair, having quench tanks (large coolant-filled tanks) above the core that open into it automatically, having a double containment (one containment building
Containment building
A containment building, in its most common usage, is a steel or reinforced concrete structure enclosing a nuclear reactor. It is designed, in any emergency, to contain the escape of radiation to a maximum pressure in the range of 60 to 200 psi...

 inside another), etc.

However, safety risks may be the greatest when nuclear systems are the newest, and operators have less experience with them. Nuclear engineer David Lochbaum explained that almost all serious nuclear accidents occurred with what was at the time the most recent technology. He argues that "the problem with new reactors and accidents is twofold: scenarios arise that are impossible to plan for in simulations; and humans make mistakes". As one director of a U.S. research laboratory put it, "fabrication, construction, operation, and maintenance of new reactors will face a steep learning curve: advanced technologies will have a heightened risk of accidents and mistakes. The technology may be proven, but people are not".

Safety culture and human errors

One relatively prevalent notion in discussions of nuclear safety is that of safety culture
Safety culture
Safety culture is a term used to describe the way in which safety is managed in the workplace, and often reflects "the attitudes, beliefs, perceptions and values that employees share in relation to safety" .-Defining safety culture:...

. The International Nuclear Safety Advisory Group, defines the term as “the personal dedication and accountability of all individuals engaged in any activity which has a bearing on the safety of nuclear power plants”. The goal is “to design systems that use human capabilities in appropriate ways, that protect systems from human frailties, and that protect humans from hazards associated with the system”.

At the same time, there is some evidence that operational practices are not easy to change. Operators almost never follow instructions and written procedures exactly, and “the violation of rules appears to be quite rational, given the actual workload and timing constraints under which the operators must do their job”. Many attempts to improve nuclear safety culture “were compensated by people adapting to the change in an unpredicted way”.

According to Areva
Areva
AREVA is a French public multinational industrial conglomerate headquartered in the Tour Areva in Courbevoie, Paris. AREVA is mainly known for nuclear power; it also has interests in other energy projects. It was created on 3 September 2001, by the merger of Framatome , Cogema and...

's Southeast Asia and Oceania director, Selena Ng, Japan's Fukushima nuclear disaster is "a huge wake-up call for a nuclear industry that hasn't always been sufficiently transparent about safety issues". She said "There was a sort of complacency before Fukushima and I don't think we can afford to have that complacency now".

An assessment conducted by the Commissariat à l’Énergie Atomique (CEA) in France concluded that no amount of technical innovation can eliminate the risk of human-induced errors associated with the operation of nuclear power plants. Two types of mistakes were deemed most serious: errors committed during field operations, such as maintenance and testing, that can cause an accident; and human errors made during small accidents that cascade to complete failure.

According to Mycle Schneider
Mycle Schneider
Mycle Schneider is a nuclear energy consultant based in Paris, and lead author of The World Nuclear Industry Status Reports...

, reactor safety depends above all on a 'culture of security', including the quality of maintenance and training, the competence of the operator and the workforce, and the rigour of regulatory oversight. So a better-designed, newer reactor is not always a safer one, and older reactors are not necessarily more dangerous than newer ones. The 1978 Three Mile Island accident in the United States occurred in a reactor that had started operation only three months earlier, and the Chernobyl disaster
Chernobyl disaster
The Chernobyl disaster was a nuclear accident that occurred on 26 April 1986 at the Chernobyl Nuclear Power Plant in Ukraine , which was under the direct jurisdiction of the central authorities in Moscow...

 occurred after only two years of operation. A serious loss of coolant occurred at the French Civaux-1 reactor in 1998, less than five months after start-up.

However safe a plant is designed to be, it is operated by humans who are prone to errors. Laurent Stricker, a nuclear engineer and chairman of the World Association of Nuclear Operators
World Association of Nuclear Operators
The World Association of Nuclear Operators is an international organisation founded in 1989 after the Chernobyl accident to foster international cooperation and professional excellence within the nuclear industry...

 says that operators must guard against complacency and avoid overconfidence. Experts say that the "largest single internal factor determining the safety of a plant is the culture of security among regulators, operators and the workforce — and creating such a culture is not easy".

Risks

The routine health risks and greenhouse gas emissions from nuclear fission power are small relative to those associated with coal, but there are several "catastrophic risks":

The extreme danger of the radioactive material in power plants and of nuclear technology in and of itself is so well-known that the US government was prompted (at the industry's urging) to enact provisions that protect the nuclear industry from bearing the full burden of such inherently risky nuclear operations. The Price-Anderson Act limits industry's liability in the case of accidents, and the 1982 Nuclear Waste Policy Act charges the federal government with responsibility for permanently storing nuclear waste.

Population density is one critical lens through which other risks have to be assessed, says Laurent Stricker, a nuclear engineer and chairman of the World Association of Nuclear Operators
World Association of Nuclear Operators
The World Association of Nuclear Operators is an international organisation founded in 1989 after the Chernobyl accident to foster international cooperation and professional excellence within the nuclear industry...

:

The KANUPP
KANUPP
The Karachi Nuclear Power Plant, widely known as KANUPP-I, is a commercial nuclear power plant, located at Karachi, Sindh Province of Pakistan. In terms of Nuclear industry, the KANUPP-I is Pakistan's first nuclear power plant and is the first nuclear power plant in the Muslim world to be constructed...

 plant in Karachi, Pakistan, has the most people — 8.2 million — living within 30 kilometres of a nuclear plant, although it has just one relatively small reactor with an output of 125 megawatts. Next in the league, however, are much larger plants — Taiwan's 1,933-megawatt Kuosheng plant with 5.5 million people within a 30-kilometre radius and the 1,208-megawatt Chin Shan plant with 4.7 million; both zones include the capital city of Taipei.

  • International Nuclear Events Scale
  • Comparative Risk Assessment
  • Statistical Risk Assessment
  • Probabilistic risk assessment
    Probabilistic risk assessment
    Probabilistic risk assessment is a systematic and comprehensive methodology to evaluate risks associated with a complex engineered technological entity ....

    • Severe Accident Risks: An Assessment for Five U.S. Nuclear Power Plants NUREG-1150
      NUREG-1150
      NUREG-1150 is an improvement on WASH-1400 and CRAC-II using the results of plant-specific Probabilistic Risk Assessments...

       1991
    • Calculation of Reactor Accident Consequences CRAC-II
      CRAC-II
      CRAC-II is both a computer code and the 1982 report of the simulation results performed by Sandia National Laboratories for the Nuclear Regulatory Commission...

       1982
    • Rasmussen Report: Reactor Safety Study WASH-1400
      WASH-1400
      WASH-1400, 'The Reactor Safety Study, was a report produced in 1975 for the Nuclear Regulatory Commission by a committee of specialists under Professor Norman Rasmussen. It "generated a storm of criticism in the years following its release"...

       1975
    • The Brookhaven Report: Theoretical Possibilities and Consequences of Major Accidents in Large Nuclear Power Plants WASH-740
      WASH-740
      WASH-740, "Theoretical Possibilities and Consequences of Major Accidents in Large Nuclear Power Plants" estimated maximum possible damage from a meltdown with no containment building at a large nuclear reactor. The report was published by the U.S...

       1957


The AP1000 has a maximum core damage frequency
Core damage frequency
Core damage frequency is a term used in probabilistic risk assessment that indicates the likelihood of an accident that would cause damage to a nuclear reactor core. Core damage accidents are considered serious because damage to the core may prevent control of the nuclear reaction, which can lead...

 of 5.09 x 10−7 per plant per year. The Evolutionary Power Reactor (EPR) has a maximum core damage frequency of 4 x 10−7 per plant per year. General Electric has recalculated maximum core damage frequencies per year per plant for its nuclear power plant designs:
BWR/4 -- 1 x 10-5
BWR/6 -- 1 x 10-6
ABWR -- 2 x 10-7
ESBWR -- 3 x 10-8

Beyond design basis events

As Fukushima showed, external threats — such as earthquakes, tsunamis, fires, flooding, tornadoes and terrorist attacks — are some of the greatest risk factors for a serious nuclear accident. Yet, nuclear plant operators have normally considered these accident sequences (called 'beyond design basis' events) so unlikely that they have not built in complete safeguards.

Forecasting the location of the next earthquake or the size of the next tsunami is an imperfect art. Nuclear plants situated outside known geological danger zones "could pose greater accident threats in the event of an earthquake than those inside, as the former could have weaker protection built in". The Fukushima I plant, for example, was "located in an area designated, on Japan's seismic risk map, as having a relatively low chance of a large earthquake and tsunami; when the 2011 tsunami arrived, it was in excess of anything its engineers had planned for".

Transparency and ethics

According to Stephanie Cooke
Stephanie Cooke
Stephanie S. Cooke is a journalist who began her reporting career in 1977 at the Associated Press. In 1980 she moved to McGraw-Hill in New York as a reporter for Nucleonics Week, NuclearFuel and Inside N.R.C. In 1984 she transferred to London and two years later covered the aftermath of the...

, it is difficult to know what really goes on inside nuclear power plants because the industry is shrouded in secrecy. Corporations and governments control what information is made available to the public. Cooke says "when information is made available, it is often couched in jargon and incomprehensible prose".

Kennette Benedict has said that nuclear technology and plant operations continue to lack transparency and to be relatively closed to public view:

Despite victories like the creation of the Atomic Energy Commission, and later the Nuclear Regular Commission, the secrecy that began with the Manhattan Project has tended to permeate the civilian nuclear program, as well as the military and defense programs.


In 1986, Soviet officials held off reporting the Chernobyl disaster for several days. The operators of the Fukushima plant, Tokyo Electric Power Co, were also criticised for not quickly disclosing information on radiation leaks from the plant. Russian President Dmitry Medvedev said there must be greater transparency in nuclear emergencies.

Historically many scientists and engineers have made decisions on behalf of potentially affected populations about whether a particular level of risk and uncertainty is acceptable for them. Many nuclear engineers and scientists that have made such decisions, even for good reasons relating to long term energy availability, now consider that doing so without informed consent is wrong, and that nuclear power safety and nuclear technologies should be based fundamentally on morality, rather than purely on technical, economic and business considerations.

Non-Nuclear Futures: The Case for an Ethical Energy Strategy is a 1975 book by Amory B. Lovins and John H. Price. The main theme of the book is that the most important parts of the nuclear power debate
Nuclear power debate
The nuclear power debate is about the controversy which has surrounded the deployment and use of nuclear fission reactors to generate electricity from nuclear fuel for civilian purposes...

 are not technical disputes but relate to personal values, and are the legitimate province of every citizen, whether technically trained or not.

2011 Fukushima I accidents

The 40-year-old Fukushima I Nuclear Power Plant
Fukushima I Nuclear Power Plant
The , also known as Fukushima Dai-ichi , is a disabled nuclear power plant located on a site in the towns of Okuma and Futaba in the Futaba District of Fukushima Prefecture, Japan. First commissioned in 1971, the plant consists of six boiling water reactors...

, built in the 1970s, endured Japan's worst earthquake on record in March 2011
2011 Tōhoku earthquake and tsunami
The 2011 earthquake off the Pacific coast of Tohoku, also known as the 2011 Tohoku earthquake, or the Great East Japan Earthquake, was a magnitude 9.0 undersea megathrust earthquake off the coast of Japan that occurred at 14:46 JST on Friday, 11 March 2011, with the epicenter approximately east...

 but had its power and back-up generators knocked out by a 7-meter tsunami that followed. The designers of the reactors at Fukushima did not anticipate that a tsunami generated by an earthquake would disable the backup systems that were supposed to stabilize the reactor after the earthquake. Nuclear reactors are such "inherently complex, tightly coupled systems that, in rare, emergency situations, cascading interactions will unfold very rapidly in such a way that human operators will be unable to predict and master them".

Lacking electricity to pump water needed to cool the atomic core, engineers vented radioactive steam into the atmosphere to release pressure, leading to a series of explosions that blew out concrete walls around the reactors. Radiation readings spiked around Fukushima as the disaster widened, forcing the evacuation of 200,000 people and causing radiation levels to rise on the outskirts of Tokyo, 135 miles (210 kilometers) to the south, with a population of 30 million.

Back-up diesel generators that might have averted the disaster were positioned in a basement, where they were overwhelmed by waves. The cascade of events at Fukushima had been foretold in a report published in the U.S. several decades ago:

The 1990 report by the U.S. Nuclear Regulatory Commission, an independent agency responsible for safety at the country’s power plants, identified earthquake-induced diesel generator failure and power outage leading to failure of cooling systems as one of the “most likely causes” of nuclear accidents from an external event.

While the report was cited in a 2004 statement by Japan’s Nuclear and Industrial Safety Agency, it seems adequate measures to address the risk were not taken by Tokyo Electric. Katsuhiko Ishibashi
Katsuhiko Ishibashi
is a professor in the Research Center for Urban Safety and Security in the Graduate School of Science at Kobe University, Japan and a seismologist who has written extensively in the areas of seismicity and seismotectonics in and around the Japanese Islands...

, a seismology professor at Kobe University
Kobe University
Shindai is one of the leading universities in Japan. It can be seen in the several rankings such as shown below.-General Rankings:The university is ranked 10th in 2010 in the ranking "Truly Strong Universities" by Toyo Keizai...

, has said that Japan’s history of nuclear accidents stems from an overconfidence in plant engineering. In 2006, he resigned from a government panel on nuclear reactor safety, because the review process was rigged and “unscientific”.

According to the International Atomic Energy Agency
International Atomic Energy Agency
The International Atomic Energy Agency is an international organization that seeks to promote the peaceful use of nuclear energy, and to inhibit its use for any military purpose, including nuclear weapons. The IAEA was established as an autonomous organization on 29 July 1957...

, Japan "underestimated the danger of tsunamis and failed to prepare adequate backup systems at the Fukushima Daiichi nuclear plant". This repeated a widely held criticism in Japan that "collusive ties between regulators and industry led to weak oversight and a failure to ensure adequate safety levels at the plant". The IAEA also said that the Fukushima disaster exposed the lack of adequate backup systems at the plant. Once power was completely lost, critical functions like the cooling system shut down. Three of the reactors "quickly overheated, causing meltdowns that eventually led to explosions, which hurled large amounts of radioactive material into the air".

Louise Fréchette
Louise Fréchette
Louise Fréchette, OC was United Nations Deputy Secretary-General for eight years, and a long-time Canadian diplomat and public servant...

 and Trevor Findlay
Trevor Findlay
Trevor Findlay is director of the Nuclear Energy Futures Project at the Centre for International Governance Innovation in Waterloo, Ontario. He heads the CIGI project on the future of the IAEA...

 have said that more effort is needed to ensure nuclear safety and improve responses to accidents:

The multiple reactor crises at Japan's Fukushima nuclear power plant reinforce the need for strengthening global instruments to ensure nuclear safety worldwide. The fact that a country that has been operating nuclear power reactors for decades should prove so alarmingly improvisational in its response and so unwilling to reveal the facts even to its own people, much less the International Atomic Energy Agency, is a reminder that nuclear safety is a constant work-in-progress.



David Lochbaum, chief nuclear safety officer with the Union of Concerned Scientists
Union of Concerned Scientists
The Union of Concerned Scientists is a nonprofit science advocacy group based in the United States. The UCS membership includes many private citizens in addition to professional scientists. James J...

, has repeatedly questioned the safety of the Fukushima I Plant's General Electric
General Electric
General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...

 Mark 1 reactor design, which is used in almost a quarter of the United States' nuclear fleet.

A report from the Japanese Government to the IAEA says the "nuclear fuel in three reactors probably melted through the inner containment vessels, not just the core". The report says the "inadequate" basic reactor design — the Mark-1 model developed by General Electric — included "the venting system for the containment vessels and the location of spent fuel cooling pools high in the buildings, which resulted in leaks of radioactive water that hampered repair work".

Following the Fukushima emergency, the European Union decided that reactors across all 27 member nations should undergo safety tests.

According to UBS AG, the Fukushima I nuclear accidents are likely to hurt the nuclear power industry’s credibility more than the Chernobyl disaster
Chernobyl disaster
The Chernobyl disaster was a nuclear accident that occurred on 26 April 1986 at the Chernobyl Nuclear Power Plant in Ukraine , which was under the direct jurisdiction of the central authorities in Moscow...

 in 1986:

The accident in the former Soviet Union 25 years ago 'affected one reactor in a totalitarian state with no safety culture,' UBS analysts including Per Lekander and Stephen Oldfield wrote in a report today. 'At Fukushima, four reactors have been out of control for weeks -- casting doubt on whether even an advanced economy can master nuclear safety.'


The Fukushima accident exposed some troubling nuclear safety issues:

Despite the resources poured into analyzing crustal movements and having expert committees determine earthquake risk, for instance, researchers never considered the possibility of a magnitude-9 earthquake followed by a massive tsunami. The failure of multiple safety features on nuclear power plants has raised questions about the nation's engineering prowess. Government flip-flopping on acceptable levels of radiation exposure confused the public, and health professionals provided little guidance. Facing a dearth of reliable information on radiation levels, citizens armed themselves with dosimeters, pooled data, and together produced radiological contamination maps far more detailed than anything the government or official scientific sources ever provided.

1986 Chernobyl disaster

The Chernobyl disaster was a nuclear accident that occurred on 26 April 1986 at the Chernobyl Nuclear Power Plant
Chernobyl Nuclear Power Plant
The Chernobyl Nuclear Power Plant or Chornobyl Nuclear Power Plant is a decommissioned nuclear power station near the city of Pripyat, Ukraine, northwest of the city of Chernobyl, from the Ukraine–Belarus border, and about north of Kiev. Reactor 4 was the site of the Chernobyl disaster in...

 in Ukraine
Ukraine
Ukraine is a country in Eastern Europe. It has an area of 603,628 km², making it the second largest contiguous country on the European continent, after Russia...

. An explosion and fire released large quantities of radioactive contamination
Radioactive contamination
Radioactive contamination, also called radiological contamination, is radioactive substances on surfaces, or within solids, liquids or gases , where their presence is unintended or undesirable, or the process giving rise to their presence in such places...

 into the atmosphere, which spread over much of Western USSR and Europe. It is considered the worst nuclear power plant accident in history, and is one of only two classified as a level 7 event on the International Nuclear Event Scale
International Nuclear Event Scale
The International Nuclear and Radiological Event Scale was introduced in 1990 by the International Atomic Energy Agency in order to enable prompt communication of safety significance information in case of nuclear accidents....

 (the other being the Fukushima Daiichi nuclear disaster
Fukushima Daiichi nuclear disaster
The is a series of equipment failures, nuclear meltdowns, and releases of radioactive materials at the Fukushima I Nuclear Power Plant, following the Tōhoku earthquake and tsunami on 11 March 2011. The plant comprises six separate boiling water reactors originally designed by General Electric ,...

). The battle to contain the contamination and avert a greater catastrophe ultimately involved over 500,000 workers and cost an estimated 18 billion ruble
Ruble
The ruble or rouble is a unit of currency. Currently, the currency units of Belarus, Russia, Abkhazia, South Ossetia and Transnistria, and, in the past, the currency units of several other countries, notably countries influenced by Russia and the Soviet Union, are named rubles, though they all are...

s, crippling the Soviet economy.
The accident raised concerns about the safety of the nuclear power industry, slowing its expansion for a number of years.

UNSCEAR has conducted 20 years of detailed scientific and epidemiological research on the effects of the Chernobyl accident. Apart from the 57 direct deaths in the accident itself, UNSCEAR predicted in 2005 that up to 4,000 additional cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...

 deaths related to the accident would appear "among the 600 000 persons receiving more significant exposures (liquidators working in 1986–87, evacuees, and residents of the most contaminated areas)". Russia, Ukraine, and Belarus have been burdened with the continuing and substantial decontamination
Decontamination
Decontamination is the process of cleansing the human body to remove contamination by hazardous materials including chemicals, radioactive substances, and infectious material...

 and health care costs of the Chernobyl disaster.

Other accidents

Serious nuclear and radiation accidents include the Chalk River accidents
Chalk River Laboratories
The Chalk River Laboratories is a Canadian nuclear research facility located near Chalk River, about north-west of Ottawa in the province of Ontario.CRL is a site of major research and development to support and advance nuclear technology, in particular CANDU reactor...

 (1952, 1958 & 2008), Mayak disaster
Kyshtym disaster
The Kyshtym disaster was a radiation contamination incident that occurred on 29 September 1957 at Mayak, a nuclear fuel reprocessing plant in Russia...

 (1957), Windscale fire
Windscale fire
The Windscale fire of 10 October 1957 was the worst nuclear accident in Great Britain's history, ranked in severity at level 5 on the 7-point International Nuclear Event Scale. The two piles had been hurriedly built as part of the British atomic bomb project. Windscale Pile No. 1 was operational in...

 (1957), SL-1
SL-1
The SL-1, or Stationary Low-Power Reactor Number One, was a United States Army experimental nuclear power reactor which underwent a steam explosion and meltdown on January 3, 1961, killing its three operators. The direct cause was the improper withdrawal of the central control rod, responsible for...

 accident (1961), Soviet submarine K-19
Soviet submarine K-19
K-19, KS-19, BS_19 was one of the first two Soviet submarines of the 658, 658м, 658с class , the first generation nuclear submarine equipped with nuclear ballistic missiles, specifically the R-13 . Its keel was laid down on 17 October 1958, christened on 8 April 1959 and launched on 11 October 1959...

 accident (1961), Three Mile Island accident
Three Mile Island accident
The Three Mile Island accident was a core meltdown in Unit 2 of the Three Mile Island Nuclear Generating Station in Dauphin County, Pennsylvania near Harrisburg, United States in 1979....

 (1979), Church Rock uranium mill spill
Church Rock Uranium Mill Spill
The Church Rock Uranium Mill Spill occurred in New Mexico, USA, in 1979 when United Nuclear Corporation's Church Rock uranium mill tailings disposal pond breached its dam. Over 1,000 tons of radioactive mill waste and millions of gallons of mine effluent flowed into the Puerco River, and...

 (1979), Soviet submarine K-431
Soviet submarine K-431
The Soviet submarine K-431 was a Soviet nuclear-powered submarine that had a reactor accident on August 10, 1985. An explosion occurred during refueling of the submarine at Chazhma Bay, Vladivostok...

 accident (1985), Goiânia accident
Goiânia accident
The Goiânia accident was a radioactive contamination accident that occurred on September 13, 1987, at Goiânia, in the Brazilian State of Goiás after an old radiotherapy source was taken from an abandoned hospital site in the city...

 (1987), Zaragoza radiotherapy accident
Radiotherapy accident in Zaragoza
The radioactive accident at the Clinic of Zaragoza was a radiological accident that occurred from December 10-20, 1990, at the Clinic of Zaragoza, in Spain....

 (1990), Costa Rica radiotherapy accident
Radiotherapy accident in Costa Rica
The radiotherapy accident in Costa Rica occurred with the Alcyon II radiotherapy unit at San Juan de Dios Hospital in San José, Costa Rica. It was related to a Cobalt-60 source that was being used for radiotherapy in 1996...

 (1996), Tokaimura nuclear accident
Tokaimura nuclear accident
The Tokaimura nuclear accident , which occurred on 30 September 1999, resulted in two deaths. At that time, it was Japan's worst civilian nuclear radiation accident. The criticality accident occurred in a uranium reprocessing facility operated by JCO , a subsidiary of Sumitomo Metal Mining Co...

 (1999), Sellafield THORP leak (2005), and the Flerus IRE Cobalt-60
Cobalt-60
Cobalt-60, , is a synthetic radioactive isotope of cobalt. Due to its half-life of 5.27 years, is not found in nature. It is produced artificially by neutron activation of . decays by beta decay to the stable isotope nickel-60...

 spill (2006).

Health impacts

In spite of accidents like Chernobyl, studies have shown that nuclear deaths are mostly in uranium mining and that nuclear energy has generated far fewer deaths than the high pollution levels that result from the use of conventional fossil fuels.

Stephanie Cooke
Stephanie Cooke
Stephanie S. Cooke is a journalist who began her reporting career in 1977 at the Associated Press. In 1980 she moved to McGraw-Hill in New York as a reporter for Nucleonics Week, NuclearFuel and Inside N.R.C. In 1984 she transferred to London and two years later covered the aftermath of the...

 says that it is not useful to make comparisons just in terms of number of deaths, as the way people live afterwards is also relevant, as in the case of the 2011 Japanese nuclear accidents
2011 Japanese nuclear accidents
This is a list of articles describing aspects of the nuclear shut-downs, failures, and nuclear meltdowns triggered by the 2011 Tōhoku earthquake and tsunami.-Fukushima nuclear power plants:* Fukushima I Nuclear Power Plant...

:

You have people in Japan right now that are facing either not returning to their homes forever, or if they do return to their homes, living in a contaminated area for basically ever. And knowing that whatever food they eat, it might be contaminated and always living with this sort of shadow of fear over them that they will die early because of cancer and induced by Caesium or Strontium or some other radionuclide that's laced their vegetables. It affects millions of people, it affects our land, it affects our atmosphere, we know now the radio nuclides from Fukushima are going into the sea. It doesn't just kill now, it kills later, and it could kill centuries later. Because the stuff that that's depositing, doesn't just end, it has a long, long life. It's affecting future generations, it's not just affecting this generation. So I'm not a great fan of coal-burning. I don't think any of these great big massive plants that spew pollution into the air are good. But I don't think it's really helpful to make these comparisons just in terms of number of deaths.


The Fukushima accident forced more than 80,000 residents to evacuate from neighborhoods around the plant.

Developing countries

There are concerns about developing countries "rushing to join the so-called nuclear renaissance without the necessary infrastructure, personnel, regulatory frameworks and safety culture". Some countries with nuclear aspirations, like Nigeria, Kenya, Bangladesh and Venezuela, have no significant industrial experience and will require at least a decade of preparation even before breaking ground at a reactor site.

The speed of the nuclear construction program in China has raised safety concerns. The challenge for the government and nuclear companies is to "keep an eye on a growing army of contractors and subcontractors who may be tempted to cut corners". China is advised to maintain nuclear safeguards in a business culture where quality and safety are sometimes sacrificed in favor of cost-cutting, profits, and corruption. China has asked for international assistance in training more nuclear power plant inspectors.

See also

  • Lists of nuclear disasters and radioactive incidents
  • Deep geological repository
    Deep geological repository
    A deep geological repository is a nuclear waste repository excavated deep within a stable geologic environment...

  • Design basis accident
    Design Basis Accident
    A design basis accident or maximum credible accident is a postulated accident that a nuclear facility must be designed and built to withstand without loss to the systems, structures, and components necessary to assure public health and safety....

  • Environmental impact of nuclear power
  • International Nuclear Events Scale
  • Nuclear accidents in the United States
    Nuclear accidents in the United States
    According to a 2010 survey of energy accidents, there have been at least 56 accidents near nuclear reactors in the United States . The most serious of these was the Three Mile Island accident in 1979...

  • Nuclear criticality safety
    Nuclear Criticality Safety
    Nuclear criticality safety is a field of nuclear engineering dedicated to the prevention of nuclear and radiation accidents resulting from an inadvertent, self-sustaining nuclear chain reaction. Additionally, nuclear criticality safety is concerned with mitigating the consequences of a nuclear...

  • Nuclear fuel response to reactor accidents
  • Nuclear power debate
    Nuclear power debate
    The nuclear power debate is about the controversy which has surrounded the deployment and use of nuclear fission reactors to generate electricity from nuclear fuel for civilian purposes...

  • Nuclear power plant emergency response team
    Nuclear power plant emergency response team
    A nuclear power plant emergency response team is an incident response team composed of plant personnel and civil authority personnel specifically trained to respond to the occurrence of an accident at a nuclear power plant....

  • Nuclear power whistleblowers
    Nuclear power whistleblowers
    The GE Three are three nuclear engineers who "blew the whistle" on safety problems at nuclear power plants in the United States in 1976. The three nuclear engineers gained the attention of journalists and the anti-nuclear movement. The GE Three returned to prominence in 2011 during the Fukushima...

  • Nuclear weapon
    Nuclear weapon
    A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from relatively small amounts of matter. The first fission bomb test released the same amount...

  • Passive nuclear safety
    Passive nuclear safety
    Passive nuclear safety is a safety feature of a nuclear reactor that does not require operator actions or electronic feedback in order to shut down safely in the event of a particular type of emergency...

  • Yucca Mountain nuclear waste repository
  • Safety code (nuclear reactor)
    Safety code (nuclear reactor)
    In the context of nuclear reactors, a safety code is a computer program used to analyze the safety of a reactor, or to simulate possible accident conditions.- External links :* *...


External links

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