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==Possible design limitations==
==Possible design limitations==
The AP1000 design has an unusual containment structure and the NRC has raised concerns about "whether a shield building would be strong enough to survive an earthquake". Westinghouse submitted a detailed report in March 2010 and plans to submit another in May 2010 to demonstrate that the building is adequate.<ref name=mlw>Matthew L. Wald. [http://green.blogs.nytimes.com/2010/04/21/critics-challenge-safety-of-new-nuclear-reactor-design/?src=busln Critics Challenge Safety of New Reactor Design] ''New York Times'', April 22, 2010.</ref>
The AP1000 design has an unusual containment structure and the Nuclear Regulatory Commission is "not convinced that the shield building would survive earthquakes and other natural hazards".<ref name=ap/> As of June 2010, Westinghouse is doing new analytical work to try to convince the commission staff of its safety.<ref name=ap>Matthew L. Wald. [http://green.blogs.nytimes.com/2010/06/28/is-a-new-reactor-rust-prone/Is a New Reactor Rust-Prone?] ''Green'', June 28, 2010.</ref>


In April 2010, Arnie Gundersen, a nuclear engineer commissioned by several [[anti-nuclear]] 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 Mr. Gundersen.<ref name=mlw/> 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 Mr. Gundersen. Vaughn Gilbert, a spokesman for Westinghouse, has disputed Mr. Gundersen’s assessment.<ref name=mlw/>
In April 2010, Arnie Gundersen, a nuclear engineer commissioned by several [[anti-nuclear]] 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 Mr. Gundersen.<ref name=mlw/> 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 Mr. Gundersen. Vaughn Gilbert, a spokesman for Westinghouse, has disputed Mr. Gundersen’s assessment.<ref name=mlw>Matthew L. Wald. [http://green.blogs.nytimes.com/2010/04/21/critics-challenge-safety-of-new-nuclear-reactor-design/?src=busln Critics Challenge Safety of New Reactor Design] ''New York Times'', April 22, 2010.</ref>


== See also==
== See also==

Revision as of 04:51, 29 June 2010

Computer generated image of AP1000

Westinghouse Electric Company's AP1000 reactor design is the first Generation III+ reactor to receive final design approval from the NRC. [1] It is an evolutionary improvement on the AP600[1]. It is essentially a more powerful model with roughly the same land use.

In the spring of 2007 China National Nuclear Corp. selected the Westinghouse/Shaw consortium to build four nuclear reactors for an estimated US$8 billion.

As of April 2010, these are the only units in the world to have started construction.

Design specifications

The AP1000 is a two-loop PWR planned to produce a net 1154 MWe. [2] [3]

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 building volume

In December 2005, the Nuclear Regulatory Commission approved the final design certification for the AP1000.[2] This means that prospective builders can apply for a Combined Construction and Operating License (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 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.) The AP1000 has a maximum core damage frequency of 2.41 × 10−7 per plant per year.[4]

File:AP600PassiveContainment.jpg
Diagram of AP600/AP1000 passive safety systems

The AP1000 will be manufactured in modules designed for rail or barge shipment. This will allow the construction of many modules in parallel. The plant is designed to have fuel load 36 months after concrete is first poured. This construction period is much shorter than generation II designs. If achieved, it should greatly decrease the interest costs needed to build the plant. Such reductions would make the design much more economically competitive against other power sources than previous generation nuclear plants.

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, very unlikely, beyond the containment. In this design Westinghouse's Passive Core Cooling System (PCCS) 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.[5] 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.[2][6]

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 PCS gravity drain water tank must be topped up for as long as cooling is required.

Nuclear waste

Used fuel produced by the AP1000 can be stored indefinitely in water on the plant site.[7] 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.

Construction plans

The Chinese units will be the first to be built.

China

Chinese undergoing training for the AP1000 reactor. The first four units will be built there.

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 province, Taohuajiang in Hunan, and Pengze in Jiangxi. The NDRC is studying additional projects in Anhui, Jilin and Gansu provinces.[8] China wants to have 100 units under construction and operating by 2020, according to Aris Candris, Westinghouse's CEO.[9]

USA

As of January 2010, applications for Combined Construction and Operating Licenses (COLs) have been filed for fourteen AP1000 reactors in the United States, two each at:[10]

On April 9, 2008, Georgia Power Company reached a contract agreement with Westinghouse and Shaw for two AP1000 reactors to be built at Vogtle.[14] The contract represents the first agreement for new nuclear development since the Three Mile Island accident in 1979.[15] The COL for the Vogtle site is be based on the revision 16 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.[16]

Possible design limitations

The AP1000 design has an unusual containment structure and the Nuclear Regulatory Commission is "not convinced that the shield building would survive earthquakes and other natural hazards".[17] As of June 2010, Westinghouse is doing new analytical work to try to convince the commission staff of its safety.[17]

In April 2010, Arnie Gundersen, a nuclear engineer commissioned by several anti-nuclear 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 Mr. Gundersen.[18] 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 Mr. Gundersen. Vaughn Gilbert, a spokesman for Westinghouse, has disputed Mr. Gundersen’s assessment.[18]

See also

References

  1. ^ a b "AP 1000 Public Safety and Licensing" (web). Westinghouse. 2004-09-13. Retrieved 2008-01-21.
  2. ^ a b c T.L. Schulz. "Westinghouse AP1000 advanced passive plant" (web). Nuclear Engineering and Design; Volume 236, Issues 14–16, August 2006, Pages 1547–1557; 13th International Conference on Nuclear Energy, 13th International Conference on Nuclear Energy. ScienceDirect. Retrieved 2008-01-21. {{cite web}}: Italic or bold markup not allowed in: |publisher= (help); Italic or bold markup not allowed in: |work= (help)
  3. ^ Contact;Tom Murphy. "New Reactor Designs" (web). Article summarizes nuclear reactor designs that are either available or anticipated to become available in the United States by 2030. Energy Information Administration (EIA). Retrieved 2008-01-21.{{cite web}}: CS1 maint: multiple names: authors list (link)
  4. ^ [1] Westinghouse AP1000 PRA Summary
  5. ^ "UK AP1000 Pre-Construction Safety Report" (web). UKP-GW-GL-732 Revision 2 explains the design of the reactor safety systems as part of the process of seeking approval for construction in the UK. Westinghouse Electric Company. Retrieved 2010-02-23. {{cite web}}: Cite has empty unknown parameter: |1= (help)
  6. ^ R.A. and Worrall, A. “The AP1000 Reactor the Nuclear Renaissance Option.” Nuclear Energy 2004.
  7. ^ Westinghouse certain of safety, efficiency of nuclear power, Pittsburgh Post-Gazette, March 29, 2009
  8. ^ Li Qiyan (September 11, 2008). "U.S. Technology Picked for Nuclear Plants". Caijing. Retrieved 2008-10-29.
  9. ^ Pfister, Bonnie (2008-06-28). "China wants 100 Westinghouse reactors". Pittsburgh Tribune-Review. Retrieved 2008-10-29.
  10. ^ "Combined License Applications for New Reactors". U.S. Nuclear Regulatory Commission (NRC). January 04, 2010. Retrieved 2010-02-03. {{cite web}}: Check date values in: |date= (help)
  11. ^ "China Selects Westinghouse AP1000 Nuclear Power Technology". Westinghouse Electric Company. December 16, 2007. Retrieved 2008-06-15.
  12. ^ "Virgil C. Summer Nuclear Site, Units 2 and 3 Application". March 27, 2008. Retrieved 2008-12-01.
  13. ^ "Turkey Point, Units 6 and 7 Application". NRC. June 30, 2008. Retrieved 2010-02-03.
  14. ^ Terry Macalister (10 April 2008). "Westinghouse wins first US nuclear deal in 30 years". The Guardian. Retrieved 2008-04-09.
  15. ^ "Georgia Power to Expand Nuclear Plant". Associated Press. Retrieved 2008-04-09.
  16. ^ "Obama Administration Announces Loan Guarantees to Construct New Nuclear Power Reactors in Georgia". The White House Office of the Press Secretary. Retrieved 2010-04-30.
  17. ^ a b Matthew L. Wald. a New Reactor Rust-Prone? Green, June 28, 2010.
  18. ^ a b Matthew L. Wald. Critics Challenge Safety of New Reactor Design New York Times, April 22, 2010.
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