Nuclear power plants are designed to prevent any abnormal incidents from occurring and, if they do, to stop the possible spread of these incidents and the leakage of radioactive materials around the plant, which can have a negative impact on the environment. To ensure optimal safety, nuclear plants in the Western world use a “defense in depth” approach, with multiple safety systems that complement the natural characteristics of the reactor core. Nuclear power plants maintain the highest standards for operational safety, cybersecurity and emergency preparedness. Comprehensive industry safety procedures and strict federal regulations keep our plants and neighboring communities safe. Nuclear power plants are designed to operate safely, with no significant effect on public health and safety and the environment.
However, any industrial activity involves some risk. To keep radioactive material from any accident out of the environment, nuclear power plants are built with several barriers. The first barrier is the sealed metal tubes, or cladding, that coat the uranium ceramic fuel pellets. The second barrier is the heavy steel reactor vessel, in the range of nine inches to one foot thick, and the primary cooling water system piping.
The third barrier is the containment building, a heavily reinforced concrete and steel structure up to several feet thick that surrounds the reactor and is designed to contain the radioactivity that could overcome the first two barriers in the unlikely event of a serious accident. All countries operating nuclear power plants have a nuclear safety inspection, and all of them work closely with the IAEA. The IAEA Convention on Nuclear Safety was adopted in Vienna on 17 June 1994 and entered into force on 24 October 1996. The International Nuclear Event Scale (INES) was developed by IAEA and OECD in 1990 to communicate and standardize the reporting of nuclear incidents or accidents to the public. The nuclear industry in the United States created a design philosophy known as “defense in depth,” which many other countries have also embraced. A 1986 NRC policy statement established safety objectives that specify the Commission's expectations regarding an acceptable level of risk to public health and safety arising from the operation of the nuclear power plant. The reassessment of safety margins is based on existing safety studies and engineering judgment to assess the behavior of a nuclear power plant when faced with a range of challenging situations. If instability of nuclear material generates unexpected behavior, it can result in an uncontrolled excursion of energy. Apart from Chernobyl, no nuclear worker or member of the public has ever died as a result of radiation exposure due to an incident at a commercial nuclear reactor.
In relation to nuclear energy, safety is closely related to security, and in the nuclear field also to safeguards. Nuclear power plant licenses issued by the NRC include criteria and requirements that ensure an acceptable level of plant safety. Eleven of the Russian reactors are of the RBMK 1000 type, similar to that of the Chernobyl nuclear power plant. See also the document on Cooperation in the Nuclear Power Industry, especially for a more complete description of WANO, focused on operation.