AP1000

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Computer generated image of AP1000

The AP1000 is a nuclear power plant designed and sold by Westinghouse Electric Company in accordance with the concept of passive nuclear safety.

In December 2005, the United States Nuclear Regulatory Commission (NRC) approved the final design certification for the AP1000.[1] This meant that prospective US builders could apply for a Combined Construction and Operating License before construction starts, the validity of which is conditional upon the plant being built as designed, and that each AP1000 should be identical. Its design is the first Generation III+ reactor to receive final design approval from the US NRC.[2] In 2008 China started building four units to the AP1000-2005 design.

Aspects of the AP1000 design have been questioned and disputed by senior scientists and engineers including John Ma (of the NRC), Edwin Lyman, and Arnold Gundersen. In December 2011, the NRC approved construction of the first US plant to use the design.[3] On February 9, 2012 the NRC approved the construction of two new reactors.[4]

Design specifications[edit]

Diagram of AP600/AP1000 passive safety systems.

The AP1000 is a two-loop pressurized water reactor[1] planned to produce a net power output of 1117 MWe.[5] It is an evolutionary improvement on the AP600,[2] essentially a more powerful model with roughly the same footprint.[1][6]

The design is less expensive[clarification needed] to build than other Generation III designs 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:[5]

  • 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.[5] 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 5.09 × 10−7 per plant per year.[7] Used fuel produced by the AP1000 can be stored indefinitely in water on the plant site.[8] Aged used fuel may also be stored in above-ground dry cask storage, in the same manner as the currently operating fleet of US power reactors.[5]

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.[9] 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][10] 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.[5]

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,[11] and a Design Certification Rule.[12] Revisions 17, 18, and 19 were also approved.[13]

Design disputes[edit]

In April 2010, a dozen environmental organizations called on the United States Nuclear Regulatory Commission to investigate possible limitations in the AP1000 reactor design. These groups appealed to three federal agencies to suspend the licensing process because they believed containment in the new design is weaker than existing reactors.[14]

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.[15] 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.[15]

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.[16]

Potentially the most damaging critique of the AP1000 comes from John Ma, a senior structural engineer at the NRC.[16]

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...[16]

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.[17] 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.[18] The NRC completed the overall design certification review for the amended AP1000 in September 2011.[19]

In May 2011, US government regulators found additional problems with the design of the shield building of the new reactors. The chairman of the Nuclear Regulatory Commission said that: computations submitted by Westinghouse about the building's design appeared to be wrong and "had led to more questions."; the company had not used a range of possible temperatures for calculating potential seismic stresses on the shield building in the event of, for example, an earthquake; and that the commission was asking Westinghouse not only to fix its calculations but also to explain why it submitted flawed information in the first place. Westinghouse said that the items the commission was asking for were not "safety significant".[20]

In November 2011, Arnold Gundersen published a further report on behalf of the AP1000 Oversight Group highlighting six areas of major concern and unreviewed safety questions requiring immediate technical review by the NRC. The report concluded that certification of the AP1000 should be delayed until the original and current “unanswered safety questions” raised by the AP1000 Oversight Group are resolved.[21]

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".[22] In response to Ms. Vancko's concerns, climate policies author and retired nuclear engineer Zvi J. Doron, replied that the AP1000’s safety is enhanced by fewer active components, not compromised as Ms. Vancko suggests.[22] As in direct contrast to currently operating reactors, the AP1000 has been designed around the concept of passive nuclear safety. In October 2013, Li Yulun, a former vice-president of China National Nuclear Corporation (CNNC), raised concerns over the safety standards of the delayed AP1000 third-generation nuclear power plant being built in Sanmen, due to the constantly changing, and consequently untested, design. Citing a lack of operating history, he also questioned the manufacturer's assertion that the AP1000 reactor's "primary system canned motor pumps" were "maintenance-free" over 60 years, the assumed life of the reactor and noted that the expansion from 600 to 1,000 megawatts has not yet been commercially proven and Westinghouse has yet to receive approval from British authorities on an improved version of AP1000.[23]

Construction plans[edit]

China[edit]

Chinese workers undergoing training for the AP1000 reactor. The Chinese units will be the first to be built.[5] The first four units will be built in China.

Four AP1000 reactors are under construction in China, at Sanmen Nuclear Power Plant in Zhejiang, and Haiyang Nuclear Power Plant in Shandong.[24] The Sanmen unit 1 is expected to be the first AP1000 to begin operating, from 2014 (it was originally scheduled to go on-line from November 2013). All four Chinese AP1000s are scheduled to be operational by 2016.[25] The first four AP1000s to be built are to an earlier revision of the design without a strengthened containment structure to provide improved protection against an aircraft crash.[26]

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.[27] China wants to have 100 units under construction and operating by 2020, according to Aris Candris, Westinghouse's previous CEO.[28]

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, the CAP1400 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.[29] In September 2014 the Chinese nuclear regulator approved the design safety analysis following a 17-month review.[30]

In December 2009, a Chinese joint venture was set up to build an initial CAP1400 near the HTR-10 Shidaowan site.[29][31] Pouring of first concrete is expected by the end of 2014.[30]

In 2014, China First Heavy Industries manufactured the first domestically produced AP1000 reactor pressure vessel, for the second AP1000 unit of Sanmen Nuclear Power Station.[32]

United States[edit]

Four AP1000 reactors are being built in the United States. Two at Vogtle (units 3&4)[33] and two at VC Summer (units 2&3).[34] All four reactors are identical and the two projects run in parallel with the first two reactors (Vogtle 3 and Summer 2) planned to be commissioned 2016 and the remaining two (Voglte 4 and Summer 3) one year later in 2017.[35]

On April 9, 2008, Georgia Power Company reached a contract agreement with Westinghouse and Shaw for two AP1000 reactors to be built at Vogtle.[36] The contract represents the first agreement for new nuclear development since the Three Mile Island accident in 1979.[37] The COL for the Vogtle site is to be based on the revision 18 to the AP1000 design.[38] On February 16, 2010, President Obama announced $8.33 billion in federal loan guarantees to construct the two AP1000 units at the Vogtle plant.[39] The cost of building the two reactors is expected to be $14 billion.[40]

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.[41] In February 2012, nine environmental groups filed a collective challenge to the certification of the Vogtle reactor design and in March they filed a challenge to the Vogtle license. In May 2013, the U.S. Court of Appeals ruled in favor of the Nuclear Regulatory Commission (NRC). Lawyers representing nine groups later issued a statement citing major errors made by the court and emphasized that the people who are living in the shadows of the current Vogtle reactor towers have the most to lose from the judgment.[42]

As of February 2012, the US Nuclear Regulatory Commission has approved the two proposed reactors at the Vogtle plant.[43]

For VC Summer unit 2&3 spending through December 31, 2013, in current dollars is forecasted to be approximately $361 million below the capital cost schedule approved in Order No. 2012-884. The present cash flow forecast indicates that SCE&G will be able to complete the units for $4.548 billion in 2007 dollars, which is the amount approved in Order No. 2012-884. The current cost estimates include changes in timing of costs and minor shifts in costs among cost categories that occur in the normal course of managing the project.[44]

In October 2013, US energy secretary Ernest Moniz announced that China was to supply components to the US nuclear power plants under construction as part of a bilateral co-operation agreement between the two countries. Since China’s State Nuclear Power Technology Co (SNPTC) acquired Westinghouses's AP1000 technology in 2006, it has developed a manufacturing supply chain capable of supplying international power projects.*1 But industry analysts have highlighted a number of problems facing China’s expansion in the nuclear market including continued gaps in their supply chain, coupled with Western fears of political interference and Chinese inexperience in the economics of nuclear power.*2.[45]

Bulgaria[edit]

On November 22, 2013, the Bulgarian economy and energy minister Dragomir Stoynev announced during a visit to the United States, that Bulgaria wants to build an AP1000 nuclear reactor as the seventh unit of the Kozloduy Nuclear Power Plant.[46] On December 11, the Bulgarian government gave its approval to Bulgarian Energy Holding (BEH) to start talks with Toshiba and Westinghouse on the new unit. Toshiba will hold a 30% share of the new unit. As of December 2013, the overall costs of the unit were estimated to be about $8 billion.[47] On December 13, talks between BEH and Westinghouse started.[48] As of December 2013, Westinghouse planned to complete preparatory work in nine months for technical, financial and economic parameters of the new unit,[49] so that construction can begin in 2016. In 2013 the Austrian Environment Agency's report on the Bulgarian Ministry for the Environment's Environmental Impact Assessment (EIA) on the proposed 7th unit of the Kozloduy Nuclear Power Plant found a number unsubstantiated claims and some serious failings in the Bulgarian EIA report.[50] On July 30, 2014 a shareholder agreement has been signed by Westinghouse Electric Company LLC and the state-owned Kozloduy NPP for the construction of the Kozloduy-7 nuclear reactor and reactor block, for an estimated total price of $5 billion.[51]

United Kingdom[edit]

In December 2013, Toshiba, through its Westinghouse subsidiary, purchased a 60% share of NuGeneration, with the intention of building 3 AP1000s at Moorside near the Sellafield nuclear reprocessing site in Cumbria, England, with a target first operation date of 2024.[52] In December 2011, the UK’s Office for Nuclear Regulation (ONR) published a design assessment report on the Westinghouse AP1000 reactor which highlighted 51 Generic Design Assessment (GDA) issues remaining which must be addressed before the assessment process would be completed.[53]

See also[edit]

References[edit]

  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. 
  2. ^ a b "AP 1000 Public Safety and Licensing" (web). Westinghouse. 2004-09-13. Archived from the original on 2007-08-07. Retrieved 2008-01-21. 
  3. ^ Wald, Matthew L. (2011-12-22). "N.R.C. Clears Way for Nuclear Plant Construction". The New York Times. 
  4. ^ "First new nuclear reactors OK'd in over 30 years". CNN. 2012-02-09. 
  5. ^ a b c d e f Adrian Bull (16 November 2010), "The AP1000 Nuclear Power Plant - Global Experience and UK Prospects" (presentation), Westinghouse UK (Nuclear Institute), retrieved 14 May 2011 
  6. ^ 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). Archived from the original on 31 December 2007. Retrieved 2008-01-21. 
  7. ^ [1] Westinghouse AP 1000 Step 2 PSA Assessment
  8. ^ Westinghouse certain of safety, efficiency of nuclear power, Pittsburgh Post-Gazette, March 29, 2009
  9. ^ "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. 
  10. ^ R.A. and Worrall, A. “The AP1000 Reactor the Nuclear Renaissance Option.” Nuclear Energy 2004.
  11. ^ Issued Design Certification - Advanced Passive 1000 (AP1000), Rev. 15 NRC Safety Evaluation Report
  12. ^ Issued Design Certification - Advanced Passive 1000 (AP1000), Rev. 15 Design Certification Rule for the AP1000 Design
  13. ^ Design Certification Application Review - AP1000 Amendment
  14. ^ "Groups say new Vogyle Reactors need study". August Chronicle. Retrieved 2010-04-24. 
  15. ^ a b Matthew L. Wald. Critics Challenge Safety of New Reactor Design New York Times, April 22, 2010.
  16. ^ a b c Adam Piore (June 2011). "Nuclear energy: Planning for the Black Swan". Scientific American. 
  17. ^ Robynne Boyd. Safety Concerns Delay Approval of the First U.S. Nuclear Reactor in Decades. Scientific American, July 29, 2010.
  18. ^ AP1000 containment insufficient for DBA, engineer claims Nuclear Engineering International, 29 April 2010.
  19. ^ ACRS Concludes AP1000 Maintains Robustness of Previously Certified Design and is Safe Westinghouse. Retrieved 2011-11-04.
  20. ^ Matthew L. Wald, Washington DC, “Regulators Find Design Flaws in New Reactors” New York Times, 20 May 2011.
  21. ^ “Fukushima and the Westinghouse-Toshiba AP1000: A Report for The AP1000 Oversight Group” Arnie Gundersen, November 10, 2011
  22. ^ a b "Sunday Dialogue: Nuclear Energy, Pro and Con". New York Times. February 25, 2012. 
  23. ^ "China nuclear plant delay raises safety concern" Eric Ng, 7 October 2013, published in South China Morning Post
  24. ^ "Second Summer AP1000 under construction". World Nuclear News. 6 November 2013. 
  25. ^ "China nuclear plant delay rises a safety concern" Eric Ng, 7 October 2013, South China Morning Post
  26. ^ Mark Hibbs (April 27, 2010), "Pakistan Deal Signals China's Growing Nuclear Assertiveness", Nuclear Energy Brief (Carnegie Endowment for International Peace), archived from the original on 17 January 2011, retrieved 25 February 2011 
  27. ^ Li Qiyan (September 11, 2008). "U.S. Technology Picked for Nuclear Plants". Caijing. Archived from the original on 15 October 2008. Retrieved 2008-10-29. 
  28. ^ Pfister, Bonnie (2008-06-28). "China wants 100 Westinghouse reactors". Pittsburgh Tribune-Review. Retrieved 2008-10-29. 
  29. ^ a b "Nuclear Power in China". World Nuclear Association. 2 July 2010. Archived from the original on 31 July 2010. Retrieved 18 July 2010. 
  30. ^ a b "CAP1400 preliminary safety review approved". World Nuclear News. 9 September 2014. Retrieved 10 September 2014. 
  31. ^ "New reactor design taking shape in China". World Nuclear News. 15 January 2014. Retrieved 16 January 2014. 
  32. ^ "China produces first AP1000 vessel". World Nuclear News. 11 June 2014. Retrieved 6 August 2014. 
  33. ^ Westinghouse (2013). "AP1000 Construction Project Updates - Voglte". 
  34. ^ Westinghouse (2013). "AP1000 Construction Project Updates - VC Summer". 
  35. ^ SCANA (2013). "Nuclear Financial Information". 
  36. ^ Terry Macalister (10 April 2008). "Westinghouse wins first US nuclear deal in 30 years". The Guardian (London). Archived from the original on 11 April 2008. Retrieved 2008-04-09. 
  37. ^ "Georgia Power to Expand Nuclear Plant". Associated Press. Archived from the original on 2008-04-13. Retrieved 2008-04-09. 
  38. ^ "NRC: Combined License Application Documents for Vogtle, Units 3 and 4 Application". NRC. Retrieved 2011-03-11. 
  39. ^ "Obama Administration Announces Loan Guarantees to Construct New Nuclear Power Reactors in Georgia". The White House Office of the Press Secretary. Archived from the original on 1 May 2010. Retrieved 2010-04-30. 
  40. ^ Rob Pavey (May 11, 2012). "Price of Vogtle expansion could increase $900 million". The Augusta Chronicle. Retrieved July 25, 2012. 
  41. ^ Rob Pavey (April 6, 2011). "Groups want licensing of reactors suspended". Augusta Chronicle. 
  42. ^ Washington DC “Appeal Court Errs in Fukushima Vogtle/AP1000 Order” 14 May 2013
  43. ^ "NRC Approves Vogtle Reactor Construction". Nuclear Street. Retrieved 2012-02-09. 
  44. ^ SCANA (June 30, 2013). "Quarterly Report PUBLIC VERSION 3". 
  45. ^ “China set to supply components to US nuclear power plants.” Lucy Hornby (Beijing) and Ed Crooks (New York), Financial Times, 30 October 2013 “Analysis - China needs Western help for nuclear export ambitions” David Stanway (Beijing) Reuters, 17 December 2013
  46. ^ novinite.com - Bulgaria Seeks US Technology for New Unit of Kozloduy NPP
  47. ^ Tsolova, Tsvetelia (11 December 2013). "UPDATE 1-Bulgaria to start talks with Toshiba over new nuclear unit". Reuters. 
  48. ^ standartnews.com
  49. ^ novinite.com - Bulgaria, Westinghouse Ink Deal on Kozloduy NPP
  50. ^ "Kozloduy NPP – Construction of unit 7: Expert Statement to the Environmental Impact Assessment Report" Andrea Wallner, Helmut Hirsch Adhipati Y. Indradiningrat, Oda Becker, Mathias Brettner Environment Agency Austria, 2013
  51. ^ http://www.focus-fen.net/news/2014/08/01/344391/kozloduy-npp-westinghouse-american-company-and-kozloduy-npp-new-facilities-ead-signed-shareholder-agreement-for-cooperation.html
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  53. ^ "Office for Nuclear Regulation New nuclear reactors: Generic Design Assessment Westinghouse Electric Company LLC 1OO® nuclear reactor" 14 December 2011

External links[edit]