This fact sheet details the nuclear energy industry's safety standards and operating practices, as well as performance and the defense-in-depth philosophy.
February 2012Key Facts- Safety performance at America’s 104 commercial nuclear reactors is being sustained at excellent levels.
- The industry’s safety culture permeates all aspects of plant operation.
- The industry’s “defense-in-depth” safety approach uses multiple barriers that protect against accidental radiation release.
- The nuclear energy industry is one of the most heavily regulated commercial enterprises.
- Reactor operators must obtain a license from the U.S. Nuclear Regulatory Commission and train continually to rigorous standards.
- The industry is responding to the accident at Japan’s Fukushima Daiichi nuclear energy facility with plans to make plants even safer.
Safety Is the Nuclear Energy Industry’s Highest PriorityThe nuclear energy industry is committed to operating its facilities in a way that protects the health and safety of its employees and the public, in addition to protecting and improving the environment.
The industry has a demonstrated commitment to operating its facilities safely. The industry’s safety performance has been sustained at high levels, as indicated by numerous government and industry safety measures. This high performance is the result of high standards of operations, robust facility designs built and operated with a “defense-in-depth” safety philosophy, government and industry oversight of plant operations, and the dedication of a well-trained and experienced work force that recognizes that safety is a prerequisite for successful plant operations.
Safety and Operating PerformanceDramatic gains in safety, reliability and productivity have been realized at U.S. nuclear power plants over the past two decades. All of the safety-related metrics tracked by the independent Nuclear Regulatory Commission and the industry demonstrate excellence.
For example, in 2010, record lows were achieved in unplanned automatic plant shutdowns—0.21 per plant—and in lost-time accident rates—0.9 accidents per 200,000 worker-hours. Statistics from other industries through 2010, as compiled by the U.S. Bureau of Labor Statistics, show that it is safer to work at a nuclear power plant than in the manufacturing sector. Other metrics, such as forced plant outage rates, unplanned safety system actuations and plant events with safety implications, were all down or level with 2009.
Nuclear power plant reliability is unmatched by any other electricity generation capability. For the past seven years, the industry has achieved a nearly 90 percent average capacity factor, a measure of the amount of electricity actually produced compared to the plant’s maximum output potential. The highest quartile of nuclear plants operated at 95 percent over the latest three-year period.
Operating Practices at the Highest StandardsCommercial 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 facility’s replica simulator to demonstrate his or her capabilities. The six-year license covers only the facility in which the operator works.
But receiving the license does not end the learning process. 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, depending of the shift schedule at the facility.
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. INPO 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 benchmarking effort includes examining plants in other countries to ensure that the best practices in the world are emulated.
Defense-in-Depth Safety PhilosophyAmerica’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 energy facilities, 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 industry harmed no one.
Government and Industry OversightThe nuclear energy industry is one of the most heavily regulated commercial enterprises. The principal responsibility for government oversight lies with the independent Nuclear Regulatory Commission, 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 facilities 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, fines— and can even order the shutdown of a facility. At least two NRC resident inspectors are assigned to every U.S. nuclear energy facility, 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 (INPO), 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.
Response to the Accident at Fukushima DaiichiWithin days of the accident in Japan, the U.S. nuclear energy industry conducted detailed inspections of every facility to ensure that all safety equipment was in place and fully operational. The reviews included evaluations of safety and emergency response systems as well as assessments of personnel resources and safety programs.
The inspection process focused on issues that presented major challenges in Japan, including:
The industry is also implementing physical changes to U.S. reactors that will help U.S. facilities cope with the potential damage from earthquakes and other extreme events. The diverse and flexible coping capability approach, or “FLEX,” builds on earlier safety steps by providing an effective and efficient way to make U.S. nuclear energy facilities even safer.
FLEX addresses the major problem encountered in Fukushima Daiichi: loss of power that maintains essential reactor cooling capacity. FLEX will provide the capability to cope for an extended period of time with a loss of off-site power through the use of installed and portable equipment. FLEX will help to maintain cooling if normal systems fail by stationing additional power sources and pumps to provide cooling water to the reactors.