Everything about Nuclear Safety totally explained
Nuclear safety covers the actions taken to prevent
nuclear and radiation accidents or to limit their consequences. This covers
nuclear power plants as well as all other nuclear facilities, the transportation of nuclear materials, the use and storage of nuclear materials for medical, power, industry, and military uses. In addition, there are safety issues involved in products created with radioactive materials. Some of the products are legacy ones (such as
watch faces), others, like
smoke detectors, are still being produced.
Nuclear weapon safety, as well as the safety of military research involving nuclear materials, is generally handled by separate agencies than civilian safety, for various reasons, including secrecy.
Agencies
Many nations utilizing
nuclear power have special institutions overseeing and regulating nuclear safety.
Internationally the
International Atomic Energy Agency "works for the safe, secure and peaceful uses of nuclear science and technology."
Civilian
nuclear safety in the U.S. is regulated by the
Nuclear Regulatory Commission (NRC). The safety of nuclear plants and materials controlled by the U.S. government for research, weapons production, and those powering naval vessels, isn't governed by the NRC.
In the UK nuclear safety is regulated by the
Nuclear Installations Inspectorate (NII) and the Defence Nuclear Safety Regulator (DNSR).
Key concepts
Concerns
There are concerns that a combination of human and mechanical error at a nuclear facility could result significant harm to people and the environment:
Operating nuclear reactors contain large amounts of radioactive fission products which, if dispersed, could pose a direct radiation hazard, contaminate soil and vegetation, and be ingested by humans and animals. Human exposure at high enough levels can cause both short-term illness and death, and longer-term deaths by cancer and other diseases.
Some specific concerns relate to:
Criticality accidents
Loss-of-coolant accident (LOCA)
Nuclear fuel response to reactor accidents
Nuclear meltdown
Nuclear terrorism
Uncontrolled power excursion
Radioactive contamination
Radioactive waste
Vulnerability of plants to attack
Nuclear power plants are generally (although not always) considered "hard" targets. In the US, plants are surrounded by a double row of tall fences which are electronically monitored. The plant grounds are patrolled by a sizeable force of armed guards. The NRC's "Design Basis Threat" criteria for plants is a secret, and so what size attacking force the plants are able to protect against is unknown. However, to scram a plant takes less than 5 seconds while unimpeded restart takes hours, severely hampering a terrorist force in a goal to release radioactivity.
Attack from the air is a more problematic concern. The most important barrier against the release of radioactivity in the event of an aircraft strike is the containment building and its missile shield. The NRC's Chairman has said "Nuclear power plants are inherently robust structures that our studies show provide adequate protection in a hypothetical attack by an airplane. The NRC has also taken actions that require nuclear power plant operators to be able to manage large fires or explosions—no matter what has caused them."
In addition, supporters point to large studies carried out by the US Electric Power Research Institute that tested the robustness of both reactor and waste fuel storage, and found that they should be able to sustain a terrorist attack comparable to the September 11 terrorist attacks in the USA. Spent fuel is usually housed inside the plant's "protected zone" or a spent nuclear fuel shipping cask; stealing it for use in a "dirty bomb" is extremely difficult. Exposure to the intense radiation would almost certainly quickly incapacitate or kill anyone who attempts to do so.
It should be noted, that the US Navy has lost two nuclear powered submarines in its history: the USS Thresher (SSN-593) which sank below crush depth and the USS Scorpion (SSN-589) which was lost most likely due to an accidental torpedo explosion. Both submarines experienced events similar to the proposed threats against land-based nuclear plants, yet their reactors have emitted almost insignificant amounts of radiation into their respective environment.
Risk assessment
International Nuclear Events Scale
Probabilistic risk assessment
- Severe Accident Risks: An Assessment for Five U.S. Nuclear Power Plants NUREG-1150 1991
- Calculation of Reactor Accident Consequences CRAC-II 1982
- Rasmussen Report: Reactor Safety Study WASH-1400 1975
- The Brookhaven Report: Theoretical Possibilities and Consequences of Major Accidents in Large Nuclear Power Plants WASH-740 1957
The AP1000 has a maximum core damage frequency 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
Enforcement organisations
International Atomic Energy Agency
United States Atomic Energy Commission
Canadian Nuclear Safety Commission
Autorité de sûreté nucléaire, the French nuclear safety authority
Radiological Protection Institute of Ireland
Federal Atomic Energy Agency in Russia
Radiation and Nuclear Safety Authority of Finland
Nuclear Installations Inspectorate (UK)
Defence Nuclear Safety Regulator (UK)
Nuclear accidents
Chernobyl disaster
Three Mile Island accident
Windscale fire
List of civilian nuclear accidents
List of civilian radiation accidents
List of military nuclear accidentsFurther Information
Get more info on 'Nuclear Safety'.
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