America’s 100-plus nuclear energy facilities 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 energy facilities and neighboring communities safe.
The U.S. Nuclear Regulatory Commission, an independent federal agency, strictly regulates commercial nuclear energy facilities. The agency evaluates performance in three strategic areas: reactor safety, radiation safety and security. NRC inspectors stationed at each facility provide oversight of operation, maintenance, equipment replacement and training. If the NRC believes a facility 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. facilities. After the 2011 accident at the Fukushima Daiichi nuclear energy facility 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 facility sites and regional depots. About 1,500 pieces of equipment have been purchased or ordered.
All commercial nuclear energy facilities have emergency response procedures in the event of an accident or security event. These procedures are evaluated regularly during drills involving facility 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 is relentless in its pursuit of safety through quality facility 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
America’s 100-plus nuclear energy facilities operated at high levels of safety and efficiency in 2012, according to performance metrics compiled by the World Association of Nuclear Operators and the Institute of Nuclear Power Operations. In several key areas, commercial U.S. facilities either matched or improved upon outstanding levels of performance that help make nuclear energy a vital component of the nation’s diverse portfolio of electricity sources.
The industry matched its record-low number of unplanned shutdowns—62—set just a year earlier. This is the fourth time in the past eight years that fewer than 70 unplanned shutdowns have occurred, with the result that facilities continue to reliably generate large amounts of electricity around the clock to help stabilize the electric grid and sustain economic growth.
Nuclear energy facilities continued to maximize their operating efficiency at a rate far above other electricity sources. For the ninth time in the past 10 years the median capability factor has been at least 91.2 percent, even with a number of reactors in extended shutdowns and more reactors in refueling outages. Capacity factor, a related metric that measures total electricity generated as a percentage of year-round potential generation, was 86.4 percent in 2012, according to data compiled by the U.S. Energy Information Administration.
As has been the case every year at least for the past decade, key backup safety systems concurrently met availability goals more than 95 percent of the time, assuring that multiple layers of safety were in place as designed. 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 encompass two main cooling systems and backup power supplies used to respond in the event of unexpected situations. Each system at every plant has an availability goal just shy of 100 percent due to maintenance and testing.
In 2012, the industry posted its best industrial safety record ever, with only 0.05 industrial safety accidents per 200,000 worker-hours. As proof of the industry’s exacting standards, statistics from other industries through 2011, compiled by the U.S. Bureau of Labor Statistics, demonstrate that it is safer to work at a nuclear power plant than in the manufacturing sector, leisure and hospitality industries, and financial sector.
The 2012 median value of 1.2 percent forced loss matched a historic best set in 2006. Forced loss rate measures a plant’s outage time and power reductions that result from unplanned equipment failures, human error and other limiting conditions when the plant is expected to be generating electricity. The 2015 goal for this indicator is a median value of 1 percent. In the mid-1990s, the median value exceeded 5 percent, but it has been under 2 percent each year since 2001 and 1.5 percent or lower for eight consecutive years.
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 facility’s replica simulator to demonstrate his or her capabilities. The six-year license covers only the facility 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, 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. 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 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 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 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, which wormed 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.