The 93 nuclear power plants in the United States are among the safest and most secure industrial facilities in the world. Nuclear power plants are designed to be highly reliable and safe, but accidents can still occur that can have a negative impact on people and the environment. To reduce the risk of an accident, the International Atomic Energy Agency (IAEA) helps Member States apply international safety standards to strengthen the safety of nuclear power plants. According to estimates, about 1 to 2% of all deaths among workers in the nuclear industry can be attributed to radiation exposure.
The primary safety concern is the potential for an uncontrolled release of radioactive material, leading to contamination and consequent off-site radiation exposure. To prevent this, reactor safety is evaluated using a metric called calculated frequency of core damage, which focuses on the provision of backup hardware. European safety authorities also perform probabilistic safety analysis (PSA) for frequency of core damage, and require a 1 in 1 million core damage frequency for new designs. In 1994, the Kakrapar nuclear power plant in India was flooded due to heavy rains and failure to control a nearby water pond, which flooded the equipment in the turbine building.
In the late 1970s, the United Kingdom's Central Electricity Generation Board considered the possibility of a large, fully charged and fueled passenger aircraft being deliberately hijacked and crashed into a nuclear reactor. Analysis of next-generation reactors (SOARCA) showed that a serious accident at a United States nuclear power plant (PWR or BWR) would likely cause no immediate death, and that the risks of fatal cancer would be much lower than the overall risks of cancer. All workers were exposed to low doses of radiation as part of their work in the production of nuclear energy, the manufacture of nuclear weapons, the processing of nuclear fuel, or the research of nuclear reactors or weapons. Those responsible for nuclear energy technology in the West dedicated extraordinary efforts to ensure that a fusion of the reactor core did not occur, since a fusion of the core was supposed to create a significant public danger and, if not contained, a tragic accident with likely multiple deaths.
The International Atomic Energy Agency (IAEA) has developed a knowledge base on safety for aging and long-term operation of nuclear power plants (SKALTO), which aims to develop a framework for sharing information on aging management and long-term operation of nuclear power plants. Volcanic hazards are minimal for virtually all nuclear plants, but IAEA has developed a new Safety Guide in this regard. EDF's Blayais nuclear power plant in western France uses seawater for cooling and is protected from storm surges by dams.The IAEA has also developed suggestions to make nuclear safety stronger and more effective than before without eliminating national agencies' and governments' responsibility. Parties' obligations are largely based on the principles contained in IAEA's Safety Fundamentals document The Safety of Nuclear Installations.
Since the World Trade Center attacks in New York in 2001, there has been an increasing concern about what would happen if a large aircraft were used to attack a nuclear facility with the intention of releasing radioactive materials.