A nuclear accident and radiation is defined by the International Atomic Energy Agency (IAEA) as "an event that has caused significant consequences for people, neighborhoods or facilities." Examples include lethal effects for individuals, radioactive isotopes to the environment, or reactor core melting. "A prime example of a" major nuclear accident "is one where the reactor core is damaged and a large number of radioactive isotopes are released, as in the Chernobyl disaster in 1986.
The impact of nuclear accidents has been a topic of debate since the first nuclear reactor was built in 1954, and has been a key factor in public concerns about nuclear facilities. Technical measures to reduce the risk of accidents or to minimize the amount of radioactivity released into the environment have been adopted, but human error persists, and "there are many accidents with various and almost immediate impacts and incidents". In 2014, there are more than 100 nuclear accidents and serious incidents of nuclear power use. Fifty-seven accidents have occurred since the Chernobyl disaster, and about 60% of all nuclear-related accidents occur in the US. Serious nuclear power accident including Fukushima Daiichi nuclear disaster (2011), Chernobyl disaster (1986), Three Mile Island crash (1979), and SL-1 accident (1961). Nuclear power accidents can cause loss of life and huge monetary costs for remediation work.
Nuclear-powered submarine accidents include K-19 (1961), K-11 (1965), K-27 (1968), K-140 (1968), K-429 (1970), K-222 (1980), and K -431 (1985). Serious radiation/accident incidents including Kyshtym disaster, Wind Scale fire, radiotherapy accident in Costa Rica, radiotherapy accident in Zaragoza, radiation accident in Morocco, Goiania accident, radiation accident in Mexico City, radiotherapy unit accident in Thailand, and Mayapuri radiological accident in India.
The IAEA manages websites that report recent accidents.
Video Nuclear and radiation accidents and incidents
Nuclear power plant accident
One of the worst nuclear accidents to date is the Chernobyl disaster that occurred in 1986 in Ukraine. The accident killed 31 people directly and damaged about $ 7 billion of property. A study published in 2005 estimated that there would eventually be up to 4,000 additional cancer deaths associated with accidents among those affected by significant radiation levels. Radioactive fallout from accidents is concentrated in the regions of Belarus, Ukraine and Russia. Other studies have estimated more than one million cancer deaths in the end from Chernobyl. Estimated deaths from cancer are strongly opposed. Industrial bodies, the UN and the DOE claim that the number of cancer deaths that can be legally verified will be traceable to the disaster. UN agencies, DOEs and industries all use epidemiologically resolvable deadlines as cutoffs below which they can not legitimately prove to be from disasters. Independent research statistically calculates the fatal cancer of the dose and population, although the number of additional cancers will be below the measurement epidemiological threshold of about 1%. These are two very different concepts and lead to large variations in estimates. Both are reasonable projections with different meanings. About 350,000 people were forced to move from these areas immediately after the accident.
Social scientist and energy policy expert, Benjamin K. Sovacool has reported that worldwide there are 99 accidents in nuclear power plants from 1952 to 2009 (defined as incidents that result in the loss of human life or more than 50,000 US dollars of property damage, used the US federal government to determine the major energy accident to report), with a total property damage of US $ 20.5 billion. Fifty-seven accidents have occurred since the Chernobyl disaster, and nearly two-thirds (56 of 99) of all nuclear-related accidents have occurred in the US. There are relatively few casualties associated with nuclear power plant accidents.
Maps Nuclear and radiation accidents and incidents
Nuclear reactor reactor
The vulnerability of nuclear plants to deliberate attacks is of concern in the field of nuclear safety and security. Nuclear power plants, civil research reactors, certain naval fuel facilities, uranium enrichment plants, fuel fabrication plants, and even uranium mines are potentially vulnerable to attacks that can cause widespread radioactive contamination. The attack threats are of several common types: command based ground based attacks on equipment that, if disabled, can cause reactor core leakage or wide spread of radioactivity; and external attacks such as planes crashing into reactor complexes, or cyber attacks.
The 9/11 Commission of the United States found that nuclear power plants are potential targets that were originally considered for the 11 September 2001 attacks. If terrorist groups could seriously damage the safety system to cause a nuclear crisis at nuclear power plants, and/or simply damage sources spent fuel, such attacks can cause widespread radioactive contamination. The American Federation of Scientists has said that if the use of nuclear power is significantly expanded, nuclear facilities must be made very safe from attacks that can release large amounts of radioactivity into society. The new reactor design has a passive nuclear safety feature, which can help. In the United States, the NRC conducts "Force on Force" (FOF) training in all nuclear power plants (PLTN) at least once every three years.
Nuclear reactors became favored targets during the military conflict and, over the last three decades, have been repeatedly attacked during military air strikes, occupations, invasions and campaigns. Various acts of civil disobedience since 1980 by the Plowshares peace group have shown how nuclear weapons facilities can be penetrated, and the group's actions constitute a tremendous security breach at a nuclear weapons factory in the United States. The National Nuclear Security Administration has acknowledged the seriousness of the action of Plankshares 2012. Non-proliferation policy experts questioned "the use of private contractors to provide security to facilities that produce and store the most dangerous military materials of government property". The nuclear weapons material on the black market is a global concern, and there is concern about the possibility of blasting small nuclear weapons or dirty bombs by militant groups in big cities, causing significant loss of lives and property.
The number and sophistication of cyber attacks is on the rise. Stuxnet is a computer worm found in June 2010 that is believed to have been created by the United States and Israel to attack Iran's nuclear facilities. It shuts down the security device, causing the centrifugal to spin out of control. The South Korean nuclear power plant computer (KHNP) was hacked in December 2014. Cyber ​​attacks involve thousands of phishing emails containing malicious code, and information is stolen.
Radiation and accidents and other incidents
Between July 16, 1945 and September 23, 1992, the United States maintained a strong nuclear testing program, with the exception of a moratorium between November 1958 and September 1961. With official counts, a total of 1,054 nuclear tests and two nuclear strikes were carried out, with more than 100 of them taking place at locations in the Pacific Ocean, over 900 of them on the Nevada Test Site, and ten at various sites in the United States (Alaska, Colorado, Mississippi, and New Mexico). Until November 1962, most US tests were atmospheric (ie above ground); after the receipt of the Partial Test Ban Ban Treaty are all arranged underground, to prevent the spread of the nuclear fallout.
The US nuclear atmospheric testing program exposes a number of populations to the dangers of fallout. Estimating the exact number, and the exact consequences, of people who are exposed to medicines is very difficult, with the exception of the high exposure of Marshall Islanders and Japanese fishermen in the case of Castle Bravo incident in 1954. A number of groups of US citizens - - especially farmers and residents of city- cities that follow the wind direction of the Nevada Test Site and US military workers in various tests - have demanded compensation and recognition for their exposure, many of which succeed. Part of the Radiation Exposure Compensation Act of 1990 allows for systematic compensation claims submissions in connection with testing as well as persons employed in nuclear weapons facilities. As of June 2009, a total of more than $ 1.4 billion has been awarded as compensation, with more than $ 660 million going to be "downwinders".
Trading and theft
The International Atomic Energy Agency says there are "persistent problems with illicit trafficking of nuclear material and other radioactive materials, theft, loss and other illegal activities". The IAEA Illicit Nuclear Trafficking Database records 1,266 incidents reported by 99 countries over the past 12 years, including 18 incidents involving HEU or plutonium trade:
- Security specialist Shaun Gregory argues in an article that terrorists have attacked Pakistan's nuclear facilities three times in the past; twice in 2007 and one time in 2008.
- In November 2007, thieves with unknown intentions infiltrated the Pelindaba nuclear research facility near Pretoria, South Africa. The robbers escaped without obtaining any of the uranium held at the facility.
- In February 2006, Oleg Khinsagov of Russia was arrested in Georgia, along with three Georgian accomplices, with 79.5 grams of 89 percent enriching HEU.
- The poisoning of Alexander Litvinenko with radioactive polonium "represents an unpleasant landmark: the beginning of an era of nuclear terrorism," according to Andrew J. Patterson.
Accident category
Nuclear crisis
A nuclear crisis is a severe nuclear reactor accident that results in damage to the reactor core from overheating. It has been defined as an accidental fusion of the nuclear reactor core, and refers to the collapse either in a core or a part. The core melting accident occurs when the heat generated by the nuclear reactor exceeds the heat discharged by the cooling system to the point where at least one nuclear fuel element exceeds its melting point. This is different from the failure of the fuel element, which is not caused by high temperatures. A crisis may be caused by loss of coolant, coolant pressure loss, or low cooling flow rate or be the result of a criticality trip in which the reactor operates at a power level that exceeds the design boundaries. Alternately, in a reactor plant such as the RBMK-1000, external fire can harm the nucleus, leading to destruction.
Large-scale nuclear damage at civilian nuclear power plants includes:
- Lucens reactor, Switzerland, in 1969.
- Three Mile Island accident in Pennsylvania, USA, in 1979.
- the Chernobyl disaster at Chernobyl Nuclear Power Plant, Ukraine, USSR, in 1986.
- Fukushima Daiichi nuclear disaster after the earthquake and tsunami in Japan, March 2011.
Another core weakness occurs in:
- NRX (military), Ontario, Canada, in 1952
- BORAX-I (experimental), Idaho, U.S., in 1954
- EBR-I, Idaho, U.S., in 1955
- Windscale (military), Sellafield, England, in 1957 (see Windscale fires)
- Sodium Reactor Trial, Santa Susana Field Laboratory (civil), California, USA, in 1959
- Fermi 1 (civilian), Michigan, U.S., in 1966
- Chapelcross (civilian) nuclear power plant, Scotland, in 1967
- Nuclear Power Station Saint-Laurent (Civil), France, in 1969
- A1 plants, (civilians) in JaslovskÃÆ'Â © Bohunice, Czechoslovakia, in 1977
- Nuclear Power Station Saint-Laurent (civil), France, in 1980
Eight Soviet Navy nuclear submarines have experienced nuclear core crises or radiation incidents: K-19 (1961), K-11 (1965), K-27 (1968), K-140 (1968), K-429 (1970) , K-14 -222 (1980), K-314 (1985), and K-431 (1985).
Crash criticism
Critical accidents (also sometimes referred to as "travel" or "power travel") occur when a nuclear chain reaction is accidentally allowed to occur in fissile material, such as enriched uranium or plutonium. The Chernobyl accident is not universally regarded as an example of a critical crash, as it occurs in an operating reactor at a power plant. The reactor should be in a controlled critical state, but the chain reaction control is lost. The accident destroyed the reactor and left a large, uninhabitable geographic area. In a smaller-scale accident at Sarov, a technician working with highly enriched uranium was lit up in preparation for an experiment involving a ball of fissile material. The Sarov accident is interesting because the system remains critical for several days before it can be stopped, although it is safely located in a sheltered experimental space. This is an example of a limited scope of accidents in which only a few people can be harmed, while no radioactive release to the environment occurs. Critical accidents with the release of limited sites from both radiation (gamma and neutron) and the very small release of radioactivity occurred in Tokaimura in 1999 during the production of enriched uranium fuel. Two workers died, one third were permanently injured, and 350 residents were exposed to radiation. By 2016, critical accidents are reported at the OKBM Afrikantov Critical Test Facility in Russia.
Decay heat
The ugliness of a heat accident is where heat generated by radioactive decay causes harm. In large nuclear reactors, the loss of a coolant accident can damage the core: for example, the Three Mile Island PWR reactor has recently been closed for a long time without cooling water. As a result, nuclear fuel is damaged, and the core is partially melted. Decay heat dissipation is a significant reactor safety problem, especially immediately after closure. Failure to remove the decay heat can cause the core temperature of the reactor to rise to dangerous levels and has caused a nuclear accident. Removal of heat is usually achieved through multiple redundant and diverse systems, and heat is often lost to the 'heat sink end' which has a large capacity and does not require active power, although this method is usually used after the decay heat has been reduced to a very small value. The main cause of release of radioactivity in a Three Mile Island crash is a pilot-assisted valve operated on a main loop stuck in an open position. This causes the overflow tank to be ruptured to break and release large amounts of radioactive cooling water into the containment building.
In 2011, the earthquake and tsunami caused the loss of electric power at the Fukushima Daiichi nuclear power plant in Japan. The heat of decay can not be eliminated, and the reactor terraces of units 1, 2 and 3 are overheated, nuclear fuel melts, and the containment is violated. Radioactive material is released from the plant into the atmosphere and into the ocean.
Transportation
Transportation accidents may result in the release of radioactivity resulting in contamination or damaged shields resulting in direct irradiation. In Cochabamba, a set of damaged gamma radiography is transported in a passenger bus as a cargo. The gamma source is outside the shield, and illuminates some bus passengers.
In the UK, it was revealed in a court case that in March 2002 a radiotherapy source was transported from Leeds to Sellafield with a broken shield. The shield has a gap at the bottom. It is estimated that no human being is seriously harmed by escaping radiation.
Equipment failure
Equipment failure is one of the possible types of accidents. In Bia? Ystok, Poland, in 2001 the electronics associated with particle accelerators used for cancer treatment were damaged. This then causes overexposure of at least one patient. While initial failure is a simple failure of a semiconductor diode, it drives a series of events that cause radiation injury.
The cause of associated accidents is the failure of control software, as in the case involving Therac-25 medical radiotherapy equipment: the removal of hardware security interlocks in new design models exposes previously undetected bugs in control software, which can lead to patients receiving an overdose large under a set of certain conditions.
Human error
Many major nuclear accidents have been directly caused by operator or human error. This is clearly the case in Chernobyl and TMI-2 accident analysis. At Chernobyl, the test procedure is being done before the accident. The test leaders allow the operator to disable and ignore key protection circuits and warnings that would normally shut down the reactor. In TMI-2, the operator allows thousands of gallons of water to escape from the reactor plant before observing that the coolant pump behaves abnormally. The coolant pump is thus switched off to protect the pump, which in turn causes the reactor's destruction itself because the cooling is completely lost in the core.
Detailed investigations into SL-1 determined that one operator (possibly accidentally) manually pulled the 84 pound (38 kg) central control rod out about 26 inches from the treatment procedure's intention of about 4 inches.
An assessment by the Commissariat ÃÆ' l'ÃÆ'¨ergie Atomique (CEA) in France concluded that no amount of technical innovation could eliminate the risk of human-induced errors associated with nuclear power plant operations. Two types of errors are considered the most serious: errors made during field operations, such as maintenance and testing, which can cause accidents; and human mistakes made during small accidents that result in failure.
In 1946, Canadian Manhattan Project physicist Louis Slotin conducted a risky experiment known as "tickling the tail of a dragon" involving two neutron-reflective beryllium halves that were brought together around a plutonium core to bring it to criticality. Against surgical procedures, the hemisphere is separated only by a screwdriver. The screwdriver slips and triggers the disappointment of a chain reaction reaction that fills the room with harmful radiation and blue light flashes (caused by ionized and excited air particles back to their unspoiled state). Slotin reflexively separates the hemisphere as a reaction to hot flashes and blue light, preventing further irradiation of some of the co-workers in the room. However, Slotin absorbs doses of deadly radiation and dies nine days later. The famous plutonium mass used in the experiment is referred to as the core of the devil.
Missing resources
Missing source accidents, also referred to as orphan sources, are incidents where radioactive sources are lost, stolen or abandoned. The source may be harmful to humans. One case occurred in Yanango where the radiographic source was lost, also in the Samut Prakarn source teleterapy phosphorus lost and in Gilan in Iran the radiographic source damaged a welder. The most famous example of this type of event is the GoiasÃÆ' nà ¢ nia accident in Brazil.
The International Atomic Energy Agency has provided guidance to old metal collectors on how sealed sources will look. The scrap metal industry is the place where the lost source is most likely to be found.
Comparison
Comparing the historical security records of civilian nuclear energy with other forms of power generation, Ball, Roberts, and Simpson, the IAEA, and the Paul Scherrer Institute found in separate studies that during the period 1970-1992, there were only 39 deaths in the workplace of generating workers nuclear power worldwide, while over the same period of time, there are 6,400 deaths in the workplace of coal-fired power plants, 1,200 deaths in the workplace of natural gas-fired power plant workers and members of the general public caused by natural gas power plants, and 4,000 general community deaths caused by hydropower. In particular, coal-fired power plants are estimated to kill 24,000 Americans per year from lung diseases and cause 40,000 heart attacks per year in the United States. According to Scientific American , the average coal-fired power plant emits 100 times more radiation per year than a relative-sized nuclear power plant in the form of toxic coal waste known as fly ash.
In the case of energy accidents, hydroelectric power is responsible for most of the fatalities, but nuclear power plants ranks first in terms of their economic costs, accounting for 41 percent of all property damage. Oil and hydroelectrics follow about 25 percent each, followed by natural gas of 9 percent and coal by 2 percent. Excluding Chernobyl and Dam Shimantan, the other three most expensive accidents involved the Exxon Valdez (Alaska) oil spill, the Prestige oil spill (Spain), and the Three Mile Island (Pennsylvania) nuclear accident.
Nuclear security
Nuclear security includes measures taken to prevent nuclear accidents and radiation or to limit the consequences. This includes nuclear power plants as well as all other nuclear facilities, nuclear material transport, and the use and storage of nuclear materials for medical, electrical, industrial, and military use.
The nuclear power industry has improved the safety and performance of the reactor, and has proposed a safer (but generally untested) reactor design but there is no guarantee that the reactor will be properly designed, built and operated. Mistakes do occur and the reactor designers at Fukushima in Japan did not anticipate that the tsunami generated by the earthquake would deactivate the reserve system that was supposed to stabilize the reactor after the earthquake. According to UBS AG, the Fukushima I nuclear accident has raised doubts as to whether even advanced economies like Japan can master nuclear safety. Catastrophic scenarios involving terrorist attacks can also be imagined.
In his book Normal Accident , Charles Perrow says that multiple and unexpected failures are built into complex and tightly integrated nuclear reactor systems. Nuclear power plants can not be operated without some major accidents. Such accidents are unavoidable and can not be designed. An interdisciplinary team from MIT estimates that given the expected growth of nuclear power from 2005 - 2055, at least four serious nuclear accidents will occur in that period. To date, there have been five serious (core damage) accidents in the world since 1970 (one at Three Mile Island in 1979, one in Chernobyl in 1986 and three in Fukushima-Daiichi in 2011), corresponding to the beginning of operations. second generation reactor. This leads to an average of one serious accident every eight years worldwide.
Acute radiation exposure effects
See also
References
Further reading
External links
- US. Nuclear Accidents (lutins.org) the most comprehensive list of online incidents involving US nuclear facilities and vessels, 1950-present
- The US Nuclear Regulatory Commission (NRC) website with search function and electronic public reading room
- The International Atomic Energy Agency website with an extensive online library
- Plutopia: Nuclear Family, Atomic City, and Great Soviet and American Plutonium Disaster
- Citizens Concern for Nuclear Security A detailed article on US nuclear watchdog activities
- World Nuclear Association: Radiation Dose Background ionizing radiation and dose
- Radiological Incidents Database. Extensive list of radiological and well-referenced incidents
- "Criticality Crash Review". Archived from the original on 2004-12-09 . Retrieved 2004-12-09 . < span>
- Nuclear Files.org List of nuclear accidents
- Annotated bibliography for civil nuclear accident from Alsos Digital Library for Nuclear Issues
- Critical Clock: Three Mile Island, Nuclear Heritage, and National Security. Albert J. Fritsch, Arthur H. Purcell, and Mary Byrd Davis (2005). Latest edition, June 2006
- Emergency and Nuclear Radiation Resources Review of literature: what to do in the event of a nuclear accident
- Radioactivity.eu.com Radiation accident
Source of the article : Wikipedia
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