Key Facts
- America’s nuclear power plants are among the safest and most secure industrial facilities in the world. Multiple safety systems, the industry’s commitment to comprehensive safety procedures, robust training programs and stringent federal regulation keep nuclear plants and neighboring communities safe.
- The U.S. Nuclear Regulatory Commission (NRC), an independent federal agency, is a strong and effective regulator of commercial nuclear power plants. The agency evaluates each licensee's performance in three strategic areas: reactor safety, radiation safety and security. NRC inspectors stationed at each facility have oversight of all aspects of plant operation and maintenance. If the NRC believes a plant is unsafe, the agency will order it shut down.
- The industry and the NRC routinely analyze operational events worldwide to identify possible lessons for U.S. plants. After the 2011 accident at the Fukushima Daiichi nuclear plant in Japan, the NRC issued new requirements for plants to implement measures to mitigate the effects of extreme natural events. It also requested detailed design information relevant to the accident in Japan. The industry has implemented the new event mitigation requirements and continues to provide the information requested by the agency. The NRC is using this information to determine if additional safety requirements should be applied to specific sites.
- All nuclear power plants have emergency response procedures for use in the event of an accident or security threat. These procedures are evaluated regularly during drills involving plant personnel and local policy emergency management and public safety organizations. Some of these drills are evaluated by teams from the NRC and the Federal Emergency Management Agency (FEMA).
Performance Data Demonstrate the Industry’s Commitment to Safety
The performance of U.S. nuclear power plants is assessed against standards established by the World Association of Nuclear Operators (WANO) and the Institute of Nuclear Power Operations (INPO). These organizations have created indicators that continuously monitor plant performance and 10 key safety and reliability areas, as well as set goals for attaining operational excellence. A review of the most current data shows that U.S. nuclear power plants are either near or exceeding those goals.
Operating Practices at the Highest Standards
Commercial reactor operators must meet rigorous training and qualification standards before receiving a license from the NRC. Prospective operators must first pass a series of written tests covering both general and site-specific topics. Another test puts the applicant in the plant’s replica simulator to demonstrate his or her capabilities. The six-year license covers only the plant in which the operator works. Reactor operators continue training throughout the life of the license, spending one week refreshing knowledge and sharpening skills in the replica simulator for every five or six weeks of work.
The National Academy for Nuclear Training ensures that the highest standards of training are maintained. Companies licensed to operate nuclear plants must obtain and maintain accreditation for their training programs from the independent National Nuclear Accrediting Board.
Sharing operating experience is a factor in the continuous improvement of nuclear plant operating practices. The Institute of Nuclear Power Operations maintains an operating experience database and provides lessons learned for incorporation into plant programs and procedures. In addition, “good practices” documents are regularly published and used by companies to improve plant operations.
The industry also has benefited from a comprehensive benchmarking effort that establishes world-class standards for plant operations. This effort includes examining plants in other countries to ensure that the best practices in the world are emulated.
Defense-in-Depth Safety Philosophy
America’s nuclear plants are designed and operated under a defense-in-depth safety approach to prevent and mitigate accidents and releases of radiation. The key is creating multiple independent and redundant layers of defense to compensate for potential human and mechanical failures so that a single layer, no matter how robust, is exclusively relied upon. A defense-in-depth approach includes the use of access controls, physical barriers, redundant and diverse safety equipment, and emergency response measures. The physical barriers that protect against an accidental radiation release are the fuel rods, the reactor vessel and cooling system, and the steel-reinforced concrete containment building that houses the reactor vessel. All three barriers would have to be breached for a significant release of radiation to occur.
Each plant also has multiple sets of redundant and diverse plant safety systems designed to ensure that the fuel rods in the reactor vessel remain sufficiently cooled. These systems are designed and constructed under the highest quality standards and are periodically tested to ensure that they can reliably perform their safety functions.
As an added layer of defense-in-depth, each plant operator partners with their state and local emergency management agencies to develop emergency response measures. The resulting emergency plans, procedures and programs are periodically reviewed by both the NRC and FEMA. The plans and procedures are excised every two years during a drill involving licensee, state, and local emergency response organizations. Performance in this drill is evaluated by the NRC and FEMA and thoroughly critiqued to identify areas for improvement. It is widely recognized that nuclear plant emergency plans are the gold standard for planning for emergencies.
The Three Mile Island accident in 1979 demonstrated the effectiveness of the defense-in-depth safety approach. Mechanical failure and human error at the plant led to fuel rod damage and the release of radioactive materials into the containment building housing the reactor. The containment building performed its safety function by keeping the public protected from a significant release. The industry and the NRC learned many lessons from the event, but in the end, the worst accident in the history of the U.S. commercial nuclear energy industry harmed no one.
Government and Industry Oversight
The nuclear power industry is among the most heavily regulated commercial enterprises. The principal responsibility for government oversight lies with the NRC, which issues the federal licenses to construct and operate nuclear power plants. The NRC’s mission is to protect public health and safety by ensuring that each plant complies with the technical and administrative requirements established by the agency, and terms imposed by a facility license.
The NRC enforces its regulations with inspections, requirements for corrective actions and fines—and can even order the shutdown of a facility. At least two NRC resident inspectors are assigned to every U.S. nuclear power plant, serving as the NRC’s “eyes and ears” onsite every day. Altogether, the resident inspectors, inspectors from NRC’s regional offices, and other NRC personnel spend almost 6,000 hours each year inspecting and assessing power plant safety. The NRC’s reactor oversight program provides even more inspections when warranted by plant performance.
The industry also conducts peer reviews of plant operation through the INPO, which was formed in 1980 to promote excellence in all aspects of nuclear safety. An INPO team and industry peers conduct on-site, multi-week inspections at each plant once every two years, followed by a formal post-inspection briefing with the company leadership, including the chief executive officer.