Key Facts

• America’s 96 nuclear energy plants are among the safest and most secure industrial facilities. Multiple automatic safety systems, the industry’s commitment to comprehensive safety procedures and stringent federal regulation keep nuclear plants and neighboring communities safe.
• The U.S. Nuclear Regulatory Commission, an independent federal agency, strictly regulates commercial nuclear energy plants. The agency evaluates performance in three strategic areas: reactor safety, radiation safety and security. NRC inspectors stationed at each plant provide oversight of operation, maintenance, equipment replacement and training. If the NRC believes a plant is unsafe, it 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 energy plant in Japan, the NRC issued new requirements and requested detailed information in several areas relevant to the accident in Japan. The industry is taking steps to implement the new requirements and to develop the information requested by the agency.
• The industry also has developed a diverse, flexible mitigation approach to address the major problem encountered at Fukushima: the loss of power to maintain effective cooling. Building on existing safety systems, the “FLEX” program involves stationing another layer of backup equipment at plant sites and regional depots. About 1,500 pieces of equipment have been purchased or ordered.
• All commercial nuclear energy plants have emergency response procedures in the event of an accident or security event. These procedures are evaluated regularly during drills involving plant personnel and local policy, fire and emergency management organizations. NRC and Federal Emergency Management Agency expert teams evaluate some of these drills.
• The nuclear energy industry is relentless in its pursuit of safety through quality plant construction, continuous preventive maintenance and ongoing reactor operator training. This approach doesn’t just meet the standards created by the federal government—it exceeds them.

Performance Data Demonstrate the Industry’s Commitment to Safety

U.S. nuclear energy plants continued operating at high levels of safety and reliability in 2014, according to data monitored by the World Association of Nuclear Operators (WANO) and the Institute of Nuclear Power Operations (INPO). Key indicators used to track performance against industry goals set for 2015 show that, as a group, the plants that generate one-fifth of U.S. electricity supplies are approaching or already exceeding those goals.

• Capability factor. In 2014, U.S. plants operated at a median capability factor of 92 percent, according to the WANO data. This is the 11th straight year that a median capability factor of 91 percent or higher has been achieved. Capability factor measures the amount of time a plant is on line and producing electricity. A high unit capability means a plant is successful in reducing unplanned outages and completing scheduled work effectively during planned outages.
• Safety system performance. Nuclear power plants are constructed with multiple safety systems and backup power supplies so these systems are available, if needed, even when maintenance is being performed on a similar system or component. The three principal backup safety systems monitored by this indicator are two main cooling systems and backup power supplies used to respond in the event of unusual situations. The backup safety systems concurrently were available 96 percent of the time in 2013, the highest number since 2008. It also continues a decade-long trend above 93 percent. Each system at every plant has an availability goal just shy of 100 percent due to maintenance and testing.
• Industrial safety. The nuclear industry proved once again that it has one of the safest working environments in the United States, with a record 0.03 industrial safety accidents per 200,000 worker-hours in 2014, a number that has been consistently notching down over the last decade. This has remained well below the 2015 goal of 0.1 accidents per 200,000 worker-hours since 2010. Data compiled by the U.S. Bureau of Labor Statistics shows that it is safer to work at a nuclear power plant than in the manufacturing sector, leisure and hospitality industries, and financial sectors.
• Unplanned reactor shutdowns. After 69 unplanned automatic or manual shutdowns in 2013, the number resumed its downward trend in 2014 with 59 unplanned shutdowns, the lowest number recorded in the past 12 years.
• Fuel performance. Ninety-five percent of U.S. plants achieved zero fuel failures in 2014. This is the highest level ever recorded, and the 2014 mark is 21 percent greater than it was just six years earlier. This indicator measures the percentage of reactors with no failures in the metal barrier that surrounds nuclear fuel. 
• Chemistry effectiveness. This indicator measures water chemistry control, a key means to protect plant components over the long term. Last year the industry set records for excellence in this area for boiling water and pressurized water reactors. The industry’s 2015 goal already is being met for both reactor types.

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 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 licensed under a defense-in-depth safety approach. The first element is the multiple physical barriers that protect against accidental radiation release. These include fuel rods that enclose the uranium pellets used to power nuclear plants, the reactor vessel that contains the fuel rods, the steel-reinforced concrete containment building that houses the reactor vessel, and other plant safety systems. All three barriers would have to be breached for a significant release of radiation to occur.

The second element in this approach is the use of layer upon layer 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 reliably perform their safety functions.

The third element of defense-in-depth is the emergency response plan, which must be approved by both the NRC and the Federal Emergency Management Agency. Biennial exercises with local law enforcement and emergency response organizations are evaluated by the NRC and FEMA. It is widely recognized that nuclear plant emergency plans are the gold standard for planning for non-nuclear 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 byproducts into the containment building housing the reactor. The containment building performed its safety function by keeping the public protected from a significant release, and the emergency plan was activated. 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 energy industry is one of 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 plants comply with the terms of their licenses as well as all of the technical and administrative requirements imposed by the agency.

The NRC enforces its regulations with increased inspections, requirements for corrective action and fines—and can even order the shutdown of a plant. At least two NRC resident inspectors are assigned to every U.S. nuclear energy plant, where they conduct more than 2,000 hours of baseline inspections each year. Additional direct inspection is based on plant performance.

The industry also conducts peer reviews of plant operation through the Institute of Nuclear Power Operations, which formed in 1980 to promote excellence in all aspects of nuclear safety. An INPO team and industry peers conduct on-site, two-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.