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In 2009, the NRC made a safety change related to the events of September 11, ruling that all plants be designed to withstand the direct hit from a plane. To meet the new requirement, Westinghouse encased the AP1000 buildings concrete walls in steel plates. Last year Ma, a member of the NRC since it was formed in 1974, filed the first "non-concurrence" dissent of his career after the NRC granted the design approval. In it Ma argues that some parts of the steel skin are so brittle that the "impact energy" from a plane strike or storm driven projectile could shatter the wall. A team of engineering experts hired by Westinghouse disagreed...<ref name=bs11/>
In 2009, the NRC made a safety change related to the events of September 11, ruling that all plants be designed to withstand the direct hit from a plane. To meet the new requirement, Westinghouse encased the AP1000 buildings concrete walls in steel plates. Last year Ma, a member of the NRC since it was formed in 1974, filed the first "non-concurrence" dissent of his career after the NRC granted the design approval. In it Ma argues that some parts of the steel skin are so brittle that the "impact energy" from a plane strike or storm driven projectile could shatter the wall. A team of engineering experts hired by Westinghouse disagreed...<ref name=bs11/>
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In 2012, Ellen Vancko, from the Union of Concerned Scientists, said that "the Westinghouse AP1000 has a weaker containment, less redundancy in safety systems, and fewer safety features than current reactors".<ref>{{cite web |url=http://www.nytimes.com/2012/02/26/opinion/sunday/sunday-dialogue-nuclear-energy-pro-and-con.html?_r=2&pagewanted=all |title=Sunday Dialogue: Nuclear Energy, Pro and Con |author= |date=February 25, 2012 |work=New York Times }}</ref>


==Construction plans==
==Construction plans==

Revision as of 03:32, 29 February 2012

Computer generated image of AP1000.

The AP1000 is a two-loop pressurized water reactor[1] sold by Westinghouse Electric Company. In December 2005, the NRC approved the final design certification for the AP1000.[1] This meant that prospective builders could apply for a Combined Construction and Operating License before construction starts, whose validity is conditional upon the plant being built as designed, and that each AP1000 should be virtually identical. Its design is the first Generation III+ reactor to receive final design approval from the U.S. Nuclear Regulatory Commission.[2]

In 2010, 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. In response to these concerns Westinghouse prepared a modified design.[3] A US consultant engineer has also criticized the AP1000 containment design arguing that, in the case of a design-basis accident, it could release radiation; Westinghouse has denied the claim.[4] The NRC completed the overall design certification review for the amended AP1000 in September 2011.[5] In December 2011, the NRC approved construction of the first US plant to use the design.[6] On February 9, 2012 the NRC approved the construction of two new reactors [7]

Design specifications

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

The AP1000 is a two-loop pressurized water reactor planned to produce a net 1154 MWe. It is an evolutionary improvement on the AP600,[2] essentially a more powerful model with roughly the same footprint.

[1] [8]

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:[9]

  • 50% fewer safety-related valves
  • 35% fewer pumps
  • 80% less safety related piping
  • 85% less control cable
  • 45% less seismic building volume

The AP1000 design is considerably more compact in land usage than most existing PWRs, and uses under a fifth of the concrete and rebar reinforcing of older designs.[9]

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. According to the NRC, the plants will be orders of magnitude safer than those in the last study, NUREG-1150. The AP1000 has a maximum core damage frequency of 2.41 × 10−7 per plant per year.[10]

Used fuel produced by the AP1000 can be stored indefinitely in water on the plant site.[11] 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.[9]

Power reactors of this general type continue to produce heat from radioactive decay products even after the main reaction is shut down, so it is necessary to remove this heat to avoid meltdown of the reactor core. In the AP1000, Westinghouse's Passive Core Cooling System uses multiple 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.[12] 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.[1][13]

The design is intended to passively remove heat for 72 hours, after which its gravity drain water tank must be topped up for as long as cooling is required.[citation needed]

Date Milestone
January 27, 2006 NRC issues the final design certification rule (DCR)
March 10, 2006 NRC issues revised FDA for Revision 15 of the Westinghouse design
May 26, 2007 Westinghouse applies to amend the DCR (Revision 16)
September 22, 2008 Westinghouse updated its application
October 14, 2008 Westinghouse provides a corrected set for Revision 17 of the design
December 1, 2010 Westinghouse submits Revision 18 of the design
June 13, 2011 Westinghouse submits Revision 19 of the design
December 30, 2011 NRC issues the final DC amendment final rule

Revision 15 of the AP1000 design has an unusual containment structure which has received approval by the NRC, after a Safety Evaluation Report,[14] and a Design Certification Rule.[15] Revisions 17, 18, and 19 were also approved [16]

Safety concerns

In April 2010, Arnold 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 Gundersen.[17] 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.[17]

Edwin Lyman, a senior staff scientist at the Union of Concerned Scientists, has challenged specific cost-saving design choices made for both the AP1000 and ESBWR, another new design. Lyman is concerned about the strength of the steel containment vessel and the concrete shield building around the AP1000. The AP1000 containment vessel does not have sufficient safety margins, says Lyman.[18]

Potentially the most damaging critique of the AP1000 comes from John Ma, a senior structural engineer at the NRC.[18]

In 2009, the NRC made a safety change related to the events of September 11, ruling that all plants be designed to withstand the direct hit from a plane. To meet the new requirement, Westinghouse encased the AP1000 buildings concrete walls in steel plates. Last year Ma, a member of the NRC since it was formed in 1974, filed the first "non-concurrence" dissent of his career after the NRC granted the design approval. In it Ma argues that some parts of the steel skin are so brittle that the "impact energy" from a plane strike or storm driven projectile could shatter the wall. A team of engineering experts hired by Westinghouse disagreed...[18]

In 2012, Ellen Vancko, from the Union of Concerned Scientists, said that "the Westinghouse AP1000 has a weaker containment, less redundancy in safety systems, and fewer safety features than current reactors".[19]

Construction plans

China

Chinese undergoing training for the AP1000 reactor. The Chinese units will be the first to be built.[9] The first four units will be built in China.

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.[20]

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.[21] China wants to have 100 units under construction and operating by 2020, according to Aris Candris, Westinghouse's CEO.[22] However, according to a 2011 report in The Australian, AP1000 reactors are not yet in operation anywhere in the world and is an as yet unproven technology. Paul Garvey has said "it would be wise for China to build and test one or two of the new reactors before committing to a wide-scale rollout".[23]

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.[24]

In December 2009, a Chinese joint venture was set up to build an initial CAP1400 near the HTR-10 Shidaowan site. Construction is expected to start in 2013, operating in 2017.[24]

USA

As of January 2010,[needs update] applications for Combined Construction and Operating Licenses have been filed for fourteen AP1000 reactors in the United States, two each at:[25]

On April 9, 2008, Georgia Power Company reached a contract agreement with Westinghouse and Shaw for two AP1000 reactors to be built at Vogtle.[29] The contract represents the first agreement for new nuclear development since the Three Mile Island accident in 1979.[30] The COL for the Vogtle site is to be based on the revision 18 to the AP1000 design.[31] 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.[32]

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.[33] As of February 2012, the US Nuclear Regulatory Commission has approved the two proposed reactors at the Vogtle plant.[34]

See also

References

  1. ^ a b c d 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)
  2. ^ a b "AP 1000 Public Safety and Licensing". Westinghouse. 2004-09-13. Archived from the original (web) on 2007-08-07. Retrieved 2008-01-21.
  3. ^ Robynne Boyd. Safety Concerns Delay Approval of the First U.S. Nuclear Reactor in Decades. Scientific American, July 29, 2010.
  4. ^ AP1000 containment insufficient for DBA, engineer claims Nuclear Engineering International, 29 April 2010.
  5. ^ ACRS Concludes AP1000 Maintains Robustness of Previously Certified Design and is Safe Westinghouse. Retrieved 2011-11-04.
  6. ^ Wald, Matthew L. (2011-12-22). "N.R.C. Clears Way for Nuclear Plant Construction". The New York Times.
  7. ^ "First new nuclear reactors OK'd in over 30 years". CNN. 2012-02-09.
  8. ^ 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)
  9. ^ a b c d Adrian Bull (16 November 2010), "The AP1000 Nuclear Power Plant - Global Experience and UK Prospects" (presentation), Westinghouse UK, Nuclear Institute, retrieved 14 May 2011
  10. ^ [1] Westinghouse AP1000 PRA Summary
  11. ^ Westinghouse certain of safety, efficiency of nuclear power, Pittsburgh Post-Gazette, March 29, 2009
  12. ^ "UK AP1000 Pre-Construction Safety Report" (PDF). 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.
  13. ^ R.A. and Worrall, A. “The AP1000 Reactor the Nuclear Renaissance Option.” Nuclear Energy 2004.
  14. ^ Issued Design Certification - Advanced Passive 1000 (AP1000), Rev. 15 NRC Safety Evaluation Report
  15. ^ Issued Design Certification - Advanced Passive 1000 (AP1000), Rev. 15 Design Certification Rule for the AP1000 Design
  16. ^ Design Certification Application Review - AP1000 Amendment
  17. ^ a b Matthew L. Wald. Critics Challenge Safety of New Reactor Design New York Times, April 22, 2010.
  18. ^ a b c Adam Piore (June 2011). "Nuclear energy: Planning for the Black Swan". Scientific American. {{cite web}}: Missing or empty |url= (help)
  19. ^ "Sunday Dialogue: Nuclear Energy, Pro and Con". New York Times. February 25, 2012.
  20. ^ Mark Hibbs (April 27, 2010), "Pakistan Deal Signals China's Growing Nuclear Assertiveness", Nuclear Energy Brief, Carnegie Endowment for International Peace, retrieved 25 February 2011
  21. ^ Li Qiyan (September 11, 2008). "U.S. Technology Picked for Nuclear Plants". Caijing. Retrieved 2008-10-29.
  22. ^ Pfister, Bonnie (2008-06-28). "China wants 100 Westinghouse reactors". Pittsburgh Tribune-Review. Retrieved 2008-10-29.
  23. ^ Paul Garvey (December 19, 2011). "China's nuclear ambitions move to the slow lane". The Australian.
  24. ^ a b "Nuclear Power in China". World Nuclear Association. 2 July 2010. Retrieved 18 July 2010.
  25. ^ "Combined License Applications for New Reactors". U.S. Nuclear Regulatory Commission (NRC). January 4, 2010. Retrieved 2010-02-03.
  26. ^ "Virgil C. Summer Nuclear Site, Units 2 and 3 Application". March 27, 2008. Retrieved 2008-12-01.
  27. ^ "China Selects Westinghouse AP1000 Nuclear Power Technology". Westinghouse Electric Company. December 16, 2007. Retrieved 2008-06-15.
  28. ^ "Turkey Point, Units 6 and 7 Application". NRC. June 30, 2008. Retrieved 2010-02-03.,
  29. ^ Terry Macalister (10 April 2008). "Westinghouse wins first US nuclear deal in 30 years". The Guardian. London. Retrieved 2008-04-09.
  30. ^ "Georgia Power to Expand Nuclear Plant". Associated Press. Archived from the original on 2008-04-13. Retrieved 2008-04-09.
  31. ^ "NRC: Combined License Application Documents for Vogtle, Units 3 and 4 Application". NRC. Retrieved 2011-03-11.
  32. ^ "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.
  33. ^ Rob Pavey (April 6, 2011). "Groups want licensing of reactors suspended". Augusta Chronicle.
  34. ^ "NRC Approves Vogtle Reactor Construction". Nuclear Street. Retrieved 2012-02-09.


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