Advanced Pressurized Water Reactor
Encyclopedia
Westinghouse Electric Company
Westinghouse Electric Company LLC is a nuclear power company, offering a wide range of nuclear products and services to utilities throughout the world, including nuclear fuel, service and maintenance, instrumentation and control and advanced nuclear plant designs...
's AP1000 reactor design is the first Generation III+ reactor
Generation III reactor
A generation III reactor is a development of any of the generation II nuclear reactor designs incorporating evolutionary improvements in design developed during the lifetime of the generation II reactor designs...
to receive final design approval from the U.S. Nuclear Regulatory Commission
Nuclear Regulatory Commission
The Nuclear Regulatory Commission is an independent agency of the United States government that was established by the Energy Reorganization Act of 1974 from the United States Atomic Energy Commission, and was first opened January 19, 1975...
(NRC).
It is an evolutionary improvement on the AP600
AP600
The AP600 is a model of relatively small, 600 MWe nuclear power plant designed by Westinghouse Electric Company. The AP600 has passive safety features characteristic of the Generation III reactor concept. The projected core damage frequency is nearly 1000 times less than today's NRC requirements,...
. It is essentially a more powerful model with roughly the same land use.
In the spring of 2007 China National Nuclear Corp.
China Nuclear International Uranium Corporation
The China Nuclear International Uranium Corporation is a Chinese Government owned corporation involved in prospecting, and eventually mining, overseas sources of Uranium....
selected the Westinghouse/Shaw
The Shaw Group
The Shaw Group is a Fortune 500 corporation headquartered in Baton Rouge, Louisiana. As of February 27, 2011, the company employed approximately 28,000 people all over the world with 7 billion dollar revenue in 2010...
consortium to build four nuclear reactors for an estimated US$8 billion. , these are the only units in the world to have started construction.
The NRC questioned the durability of the AP1000 reactor's original shield building in the face of severe external events such as earthquakes, hurricanes, and airplane collisions. Therefore, Westinghouse modified the design. A US nuclear consultant engineer has also criticized the AP1000 containment design arguing that, in the case of a design-basis accident
Design Basis Accident
A design basis accident or maximum credible accident is a postulated accident that a nuclear facility must be designed and built to withstand without loss to the systems, structures, and components necessary to assure public health and safety....
, it could release radiation; Westinghouse has denied the claim. The NRC completed the overall design certification review for the AP1000 in September 2011.
Design specifications
Pressurized water reactor
Pressurized water reactors constitute a large majority of all western nuclear power plants and are one of three types of light water reactor , the other types being boiling water reactors and supercritical water reactors...
planned to produce a net 1154 MWe.
The design is less expensive to build than other Gen III plants partly because it uses existing technology. The design also decreases the number of components, including pipes, wires, and valves. Standardization and type-licensing should also help reduce the time and cost of construction. Because of its simplified design compared to a Westinghouse generation II PWR, the AP1000 has:
- 50% fewer safety-related valves
- 35% fewer pumps
- 80% less safety related piping
- 85% less control cable
- 45% less seismic building volume
The design is considerably more compact in land usage than most existing PWRs, and uses under a fifth of the concrete and rebar
Rebar
A rebar , also known as reinforcing steel, reinforcement steel, rerod, or a deformed bar, is a common steel bar, and is commonly used as a tensioning device in reinforced concrete and reinforced masonry structures holding the concrete in compression...
reinforcing of older designs.
In December 2005, the NRC approved the final design certification for the AP1000. This means that prospective builders can apply for a Combined Construction and Operating License
Combined Construction and Operating License
The Combined Construction and Operating License replaced the previous Draft Regulatory Guide 1145 as the licensing process for new nuclear power plants in the United States...
(COL) before construction starts, whose validity is conditional upon the plant being built as designed, and that each AP1000 should be virtually identical.
Probabilistic risk assessment
Probabilistic risk assessment
Probabilistic risk assessment is a systematic and comprehensive methodology to evaluate risks associated with a complex engineered technological entity ....
was used in the design of the plants. This enabled minimization of risks, and calculation of the overall safety of the plant. (The Nuclear Regulatory Commission is preparing a new safety study, and believes that these plants will be orders of magnitude safer than the last study, NUREG-1150
NUREG-1150
NUREG-1150 is an improvement on WASH-1400 and CRAC-II using the results of plant-specific Probabilistic Risk Assessments...
.) The AP1000 has a maximum core damage frequency
Core damage frequency
Core damage frequency is a term used in probabilistic risk assessment that indicates the likelihood of an accident that would cause damage to a nuclear reactor core. Core damage accidents are considered serious because damage to the core may prevent control of the nuclear reaction, which can lead...
of 2.41 × 10−7 per plant per year.
Passive Core Cooling System
Power reactors of this general type continue to produce heat from radioactive decay products even after the main reaction is shut down, so it's necessary to remove this heat to avoid meltdown of the reactor core and possible escape into the containment or, worse, beyond the containment. In this design Westinghouse's Passive Core Cooling System (PXS) uses less than twenty explosively operated and DC operated valves which must operate within the first 30 minutes. This is designed to happen even if the reactor operators take no action. The electrical system required for initiating the passive systems doesn't rely on external or diesel power and the valves don't rely on hydraulic or compressed air systems.If the active process to turn on the passive system works the design is intended to passively remove heat for 72 hours, after which the Passive Containment Cooling System (PCS) gravity drain water tank must be topped up for as long as cooling is required.
Safety concerns
The AP1000 design has an unusual containment structure, but the Nuclear Regulatory Commission has approved it, after Safety Evaluation Reports, and after a Design Certification Rule.The Westinghouse-proposed amendment of AP1000 has been approved up to Revision 17, and it is under way for Revision 18.
In April 2010, Arnold Gundersen
Arnold Gundersen
Arnold "Arnie" Gundersen is chief engineer of energy consulting company Fairewinds Associates and a former nuclear power industry executive, and who has questioned the safety of the Westinghouse AP1000, a proposed third-generation nuclear reactor. Gundersen has also expressed concerns about the...
, a nuclear engineer commissioned by several anti-nuclear
Anti-nuclear
The anti-nuclear movement is a social movement that opposes the use of nuclear technologies. Many direct action groups, environmental groups, and professional organisations have identified themselves with the movement at the local, national, and international level...
groups, released a report which explored a hazard associated with the possible rusting through of the containment structure steel liner. In the AP1000 design, the liner and the concrete are separated, and if the steel rusts through, "there is no backup containment behind it" according to Gundersen. If the dome rusted through the design would expel radioactive contaminants and the plant "could deliver a dose of radiation to the public that is 10 times higher than the N.R.C. limit" according to Gundersen. Vaughn Gilbert, a spokesman for Westinghouse, has disputed Gundersen’s assessment, stating that the AP1000's steel containment vessel is three-and-a-half to five times thicker than the liners used in current designs, and that corrosion would be readily apparent during routine inspection.
Nuclear waste
Used fuel produced by the AP1000 can be stored indefinitely in water on the plant site. Aged used fuel may also be stored in above-ground dry cask storage, in the same manner as the currently operating fleet of U.S. power reactors.China
- The Sanmen Nuclear Power PlantSanmen Nuclear Power PlantThe Sanmen Nuclear Power Station is a nuclear power station under construction in Sanmen County, Zhejiang Province in China. Groundbreaking for the first and second units was held February 26, 2008, and construction is planned to start on the third and fourth units during 2009...
in ZhejiangZhejiangZhejiang is an eastern coastal province of the People's Republic of China. The word Zhejiang was the old name of the Qiantang River, which passes through Hangzhou, the provincial capital...
will have six units. Site construction for the first two began in February 2008; operation is scheduled for 2013–15. - The Haiyang Nuclear Power PlantHaiyang Nuclear Power PlantTwo units at the Haiyang Nuclear Power Plant are under construction in Haiyang, Shandong province, China. It is planned to go online in 2014 and will be the second site to house AP1000 units, after the Sanmen Nuclear Power Plant. Groundbreaking happened one month ahead of schedule on...
in ShandongShandong' is a Province located on the eastern coast of the People's Republic of China. Shandong has played a major role in Chinese history from the beginning of Chinese civilization along the lower reaches of the Yellow River and served as a pivotal cultural and religious site for Taoism, Chinese...
also has six units planned. Site construction for the first two began in July 2008; operation is scheduled for 2014–15.
The first four AP1000s built are to an earlier revision of the design without a strengthened containment structure to provide improved protection against an aircraft crash.
China has officially adopted the AP1000 as a standard for inland nuclear projects. The National Development and Reform Commission (NDRC) has already approved several nuclear projects, including the Dafan plant in Hubei
Hubei
' Hupeh) is a province in Central China. The name of the province means "north of the lake", referring to its position north of Lake Dongting...
province, Taohuajiang in Hunan
Hunan
' is a province of South-Central China, located to the south of the middle reaches of the Yangtze River and south of Lake Dongting...
, and Pengze in Jiangxi
Jiangxi
' is a southern province in the People's Republic of China. Spanning from the banks of the Yangtze River in the north into hillier areas in the south, it shares a border with Anhui to the north, Zhejiang to the northeast, Fujian to the east, Guangdong to the south, Hunan to the west, and Hubei to...
. The NDRC is studying additional projects in Anhui
Anhui
Anhui is a province in the People's Republic of China. Located in eastern China across the basins of the Yangtze River and the Huai River, it borders Jiangsu to the east, Zhejiang to the southeast, Jiangxi to the south, Hubei to the southwest, Henan to the northwest, and Shandong for a tiny...
, Jilin
Jilin
Jilin , is a province of the People's Republic of China located in the northeastern part of the country. Jilin borders North Korea and Russia to the east, Heilongjiang to the north, Liaoning to the south, and Inner Mongolia to the west...
and Gansu
Gansu
' is a province located in the northwest of the People's Republic of China.It lies between the Tibetan and Huangtu plateaus, and borders Mongolia, Inner Mongolia, and Ningxia to the north, Xinjiang and Qinghai to the west, Sichuan to the south, and Shaanxi to the east...
provinces.
China wants to have 100 units under construction and operating by 2020, according to Aris Candris, Westinghouse's CEO.
CAP1400 development
In 2008 and 2009 Westinghouse made agreements to work with the State Nuclear Power Technology Corporation (SNPTC) and other institutes to develop a larger design, probably of 1400 MWe capacity, possibly followed by a 1700 MWe design. China will own the intellectual property rights for these larger designs. Exporting the new larger units may be possible with Westinghouse's cooperation.In December 2009, a Chinese joint venture was set up to build an initial CAP1400 near the HTR-10
HTR-10
HTR-10 is a 10 MWt prototype pebble bed reactor at Tsinghua University in China. Construction began in 2000 and it achieved first criticality in January 2003.In 2005, China announced its intention to scale up HTR-10 for commercial power generation...
Shidaowan site. Construction is expected to start in 2013, operating in 2017.
USA
, applications for Combined Construction and Operating LicenseCombined Construction and Operating License
The Combined Construction and Operating License replaced the previous Draft Regulatory Guide 1145 as the licensing process for new nuclear power plants in the United States...
s (COLs) have been filed for fourteen AP1000 reactors in the United States, two each at:
- Shearon Harris Nuclear Power PlantShearon Harris nuclear power plantThe Shearon Harris Nuclear Generating Station is a nuclear power plant with a single Westinghouse designed pressurized-water nuclear reactor operated by Progress Energy. It was named in honor of W. Shearon Harris, former president of Carolina Power & Light...
in North CarolinaNorth CarolinaNorth Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...
, - William States Lee III Nuclear Generating StationWilliam States Lee III Nuclear Generating StationThe William States Lee III Nuclear Station is a planned two-unit nuclear power plant. Duke Energy filed the Combined Construction and Operating License application for the plant on December 13, 2007 to the NRC...
in South CarolinaSouth CarolinaSouth Carolina is a state in the Deep South of the United States that borders Georgia to the south, North Carolina to the north, and the Atlantic Ocean to the east. Originally part of the Province of Carolina, the Province of South Carolina was one of the 13 colonies that declared independence...
, - Virgil C. Summer Nuclear Generating Station in South CarolinaSouth CarolinaSouth Carolina is a state in the Deep South of the United States that borders Georgia to the south, North Carolina to the north, and the Atlantic Ocean to the east. Originally part of the Province of Carolina, the Province of South Carolina was one of the 13 colonies that declared independence...
.
- Vogtle Electric Generating PlantVogtle Electric Generating PlantThe Alvin W. Vogtle Electric Generating Plant, also known as Plant Vogtle, is a 2-unit nuclear power plant located in Burke County, near Waynesboro, Georgia...
in GeorgiaGeorgia (U.S. state)Georgia is a state located in the southeastern United States. It was established in 1732, the last of the original Thirteen Colonies. The state is named after King George II of Great Britain. Georgia was the fourth state to ratify the United States Constitution, on January 2, 1788...
. - Levy County Nuclear Power PlantLevy County Nuclear Power PlantThe Levy County Nuclear Power Plant is the umbrella term for a proposed nuclear power plant in Levy County, Florida. Proposed in 2006, Progress Energy Florida announced the selection of in southern Levy County for the potential construction of nuclear reactors...
in FloridaFloridaFlorida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
, - Turkey Point Nuclear Generating StationTurkey Point Nuclear Generating StationTurkey Point Nuclear Generating Station is a twin reactor nuclear power station located on a 3,300-acre site 2 miles east of Homestead, Florida, United States, next to Biscayne National Park located about 25 miles south of Miami, Florida near the southernmost edge of Miami-Dade...
in FloridaFloridaFlorida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it... - Bellefonte Nuclear Generating StationBellefonte Nuclear Generating StationThe Bellefonte Nuclear Generating Station is a partially completed nuclear power plant located in Hollywood, Alabama. A total of four reactors have been proposed over a period of 40 years, and billions of dollars have been spent, but no electricity has yet been produced. The site has sat idle for...
in AlabamaAlabamaAlabama is a state located in the southeastern region of the United States. It is bordered by Tennessee to the north, Georgia to the east, Florida and the Gulf of Mexico to the south, and Mississippi to the west. Alabama ranks 30th in total land area and ranks second in the size of its inland...
.
On April 9, 2008, Georgia Power Company reached a contract agreement with Westinghouse and Shaw for two AP1000 reactors to be built at Vogtle. The contract represents the first agreement for new nuclear development since the Three Mile Island accident
Three Mile Island accident
The Three Mile Island accident was a core meltdown in Unit 2 of the Three Mile Island Nuclear Generating Station in Dauphin County, Pennsylvania near Harrisburg, United States in 1979....
in 1979. The COL for the Vogtle site is to be based on the revision 18 to the AP1000 design. On February 16, 2010, President Obama announced $8.33 billion dollars in federal loan guarantees to construct the two AP1000 units at the Vogtle plant.
Environmental groups opposed to the licensing of the two new AP1000 reactors to be built at Vogtle filed a new petition in April 2011 asking the Nuclear Regulatory Commission's commission to suspend the licensing process until more is known about the evolving Fukushima I nuclear accidents.
See also
- Nuclear powerNuclear powerNuclear power is the use of sustained nuclear fission to generate heat and electricity. Nuclear power plants provide about 6% of the world's energy and 13–14% of the world's electricity, with the U.S., France, and Japan together accounting for about 50% of nuclear generated electricity...
- Nuclear safety in the U.S.
- Economics of new nuclear power plantsEconomics of new nuclear power plantsThe economics of new nuclear power plants is a controversial subject, since there are diverging views on this topic, and multi-billion dollar investments ride on the choice of an energy source...
- Nuclear Power 2010 ProgramNuclear Power 2010 ProgramThe "Nuclear Power 2010 Program" was unveiled by the U.S. Secretary of Energy Spencer Abraham on February 14, 2002 as one means towards addressing the expected need for new power plants...
- AP600AP600The AP600 is a model of relatively small, 600 MWe nuclear power plant designed by Westinghouse Electric Company. The AP600 has passive safety features characteristic of the Generation III reactor concept. The projected core damage frequency is nearly 1000 times less than today's NRC requirements,...