AP1000

Computer generated image of AP1000

The AP1000 is a nuclear power plant designed and sold by Westinghouse Electric Company, now majority owned by Toshiba. The plant is a pressurized water reactor with improved use of passive nuclear safety. The first AP1000 is expected to start operations in 2017 in China.[1]

In December 2005, the Nuclear Regulatory Commission (NRC) approved the final design certification for the AP1000.[2] 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 NRC.[3] In 2008 China started building four units of the AP1000's 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.[4] On February 9, 2012 the NRC approved the construction of two new reactors.[5]

Design specifications


The AP1000 is a two-loop pressurized water reactor[2] planned to produce a net power output of 1,117 MWe.[6] It is an evolutionary improvement on the AP600,[3] essentially a more powerful model with roughly the same footprint.[2]

A design objective was to be less expensive to build than other Generation III designs, by both using existing technology, and needing less equipment than competing three or four cooling loop designs. The design 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:[6]

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.[6] 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.[6]

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.[2][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.[6]

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

In April 2010, a some environmental organizations called on the NRC 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]

John Ma, a senior structural engineer at the NRC was quoted on his stance about the AP1000 nuclear reactor.[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, following Ma's initial concerns, 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] This modified design satisfied the NRC, with the exception of Ma, hence the "non-concurrence". In contrast to the NRC's decision, Ma believed that computer codes used to analyze the modified design were not precise enough and some of the materials used were too brittle.[18]

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.[19] The NRC completed the overall design certification review for the amended AP1000 in September 2011.[20]

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".[21]

In November 2011, Arnold Gundersen published a further report on behalf of the AP1000 Oversight Group, which includes Friends of the Earth and Mothers against Tennessee River Radiation. The report highlighted 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.[22]

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".[23] 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.[23] 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.[24]

Construction plans

China

Chinese workers undergoing training for the AP1000 reactor. The Chinese units will be the first to be built.[6] 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.[25] The Sanmen unit 1 is expected to be the first AP1000 to begin operating, in 2017 more than three years after the original plan date.[1] All four Chinese AP1000s were scheduled to be operational by 2016,[26] but are reported to be running over two years late mainly due to key component delays and project management issues.[27] 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.[28]

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.[29] China wants to have 100 units under construction and operating by 2020, according to Aris Candris, Westinghouse's previous CEO.[30]

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 1,400 MWe capacity, possibly followed by a 1,700 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.[31] In September 2014 the Chinese nuclear regulator approved the design safety analysis following a 17-month review.[32]

In December 2009, a Chinese joint venture was set up to build an initial CAP1400 near the HTR-10 Shidaowan site.[31][33] In 2015 site preparation started, and approval to progress was expected by the end of the year.[34][35]

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.[36] In 2015 the AP1000 builds were reported to be running over two years late, mainly due to key component delays and project management issues.[27]

United States

Four AP1000 reactors are being built in the United States: two at Vogtle (units 3&4)[37] and two at VC Summer (units 2&3).[38] 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 in 2018 and the remaining two (Vogtle 4 and Summer 3) one year later in 2019.[39] Both projects are running approximately 3 years behind schedule. On April 9, 2008, Georgia Power Company reached a contract agreement with Westinghouse and Shaw for two AP1000 reactors to be built at Vogtle.[40] The contract represents the first agreement for new nuclear development since the Three Mile Island accident in 1979.[41] The COL for the Vogtle site is to be based on the revision 18 to the AP1000 design.[42] On February 16, 2010, President Obama announced $8.33 billion in federal loan guarantees to construct the two AP1000 units at the Vogtle plant.[43] The cost of building the two reactors is expected to be $14 billion.[44]

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.[45] 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).

As of February 2012, the US Nuclear Regulatory Commission has approved the two proposed reactors at the Vogtle plant.[46]

For VC Summer a delay of at least one year and extra costs of $1.2 billion were announced in October 2014, largely due to fabrication delays. Unit 2 was expected to be substantially complete in late 2018 or early 2019, with unit 3 about a year later.[47]

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. 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.[48]

Bulgaria

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.[49] 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.[50] On December 13, talks between BEH and Westinghouse started.[51] As of December 2013, Westinghouse planned to complete preparatory work in nine months for technical, financial and economic parameters of the new unit,[52] 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.[53] 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.[54]

United Kingdom

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.[55] 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.[56] Now that a UK customer have been found for the AP1000, Toshiba intends to complete the Generic Design Assessment by addressing each of these issues.

See also

References

  1. 1 2 "More delays for China's first AP1000". Nuclear Engineering International. 11 March 2016. Retrieved 12 March 2016.
  2. 1 2 3 4 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.
  3. 1 2 "AP 1000 Public Safety and Licensing". Westinghouse. 2004-09-13. Archived from the original (web) on 2007-08-07. Retrieved 2008-01-21.
  4. ↑ Wald, Matthew L. (2011-12-22). "N.R.C. Clears Way for Nuclear Plant Construction". The New York Times.
  5. ↑ "First new nuclear reactors OK'd in over 30 years". CNN. 2012-02-09.
  6. 1 2 3 4 5 6 Adrian Bull (16 November 2010), "The AP1000 Nuclear Power Plant - Global Experience and UK Prospects" (presentation), Westinghouse UK (Nuclear Institute), retrieved 14 May 2011
  7. ↑ 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. 1 2 Matthew L. Wald. Critics Challenge Safety of New Reactor Design New York Times, April 22, 2010.
  16. 1 2 3 Piore, Adam (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. ↑ Matthew L. Wald (March 2011). "Reactor Design Edges Toward Approval, but Not Without Complaints". The New York Times Company. Retrieved 15 May 2014.
  19. ↑ AP1000 containment insufficient for DBA, engineer claims Nuclear Engineering International, 29 April 2010.
  20. ↑ ACRS Concludes AP1000 Maintains Robustness of Previously Certified Design and is Safe Westinghouse. Retrieved 2011-11-04.
  21. ↑ Matthew L. Wald, Washington DC, “Regulators Find Design Flaws in New Reactors” New York Times, 20 May 2011.
  22. ↑ “Fukushima and the Westinghouse-Toshiba AP1000: A Report for The AP1000 Oversight Group” Arnie Gundersen, November 10, 2011
  23. 1 2 "Sunday Dialogue: Nuclear Energy, Pro and Con". New York Times. February 25, 2012.
  24. ↑ "China nuclear plant delay raises safety concern" Eric Ng, 7 October 2013, published in South China Morning Post
  25. ↑ "Second Summer AP1000 under construction". World Nuclear News. 6 November 2013.
  26. ↑ "China nuclear plant delay rises a safety concern" Eric Ng, 7 October 2013, South China Morning Post
  27. 1 2 Steve Kidd (23 February 2015). "How serious are the delays in China's nuclear programme?". Nuclear Engineering International. Retrieved 8 March 2015.
  28. ↑ 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
  29. ↑ 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.
  30. ↑ Pfister, Bonnie (2008-06-28). "China wants 100 Westinghouse reactors". Pittsburgh Tribune-Review. Retrieved 2008-10-29.
  31. 1 2 "Nuclear Power in China". World Nuclear Association. 2 July 2010. Archived from the original on 31 July 2010. Retrieved 18 July 2010.
  32. ↑ "CAP1400 preliminary safety review approved". World Nuclear News. 9 September 2014. Retrieved 10 September 2014.
  33. ↑ "New reactor design taking shape in China". World Nuclear News. 15 January 2014. Retrieved 16 January 2014.
  34. ↑ "China looks forward to reactor firsts". World Nuclear News. 14 September 2015. Retrieved 24 September 2015.
  35. ↑ LIAO Liang (September 2015). INTRODUCTION of CAP1400 (PDF). SNERDI (Report) (IAEA). Retrieved 24 February 2016.
  36. ↑ "China produces first AP1000 vessel". World Nuclear News. 11 June 2014. Retrieved 6 August 2014.
  37. ↑ Westinghouse (2013). "AP1000 Construction Project Updates - Vogtle".
  38. ↑ Westinghouse (2013). "AP1000 Construction Project Updates - VC Summer".
  39. ↑ SCANA (2013). "Nuclear Financial Information".
  40. ↑ 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.
  41. ↑ "Georgia Power to Expand Nuclear Plant". Associated Press. Archived from the original on 2008-04-13. Retrieved 2008-04-09.
  42. ↑ "NRC: Combined License Application Documents for Vogtle, Units 3 and 4 Application". NRC. Retrieved 2011-03-11.
  43. ↑ "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.
  44. ↑ Rob Pavey (May 11, 2012). "Price of Vogtle expansion could increase $900 million". The Augusta Chronicle. Retrieved July 25, 2012.
  45. ↑ Rob Pavey (April 6, 2011). "Groups want licensing of reactors suspended". Augusta Chronicle.
  46. ↑ "NRC Approves Vogtle Reactor Construction". Nuclear Street. Retrieved 2012-02-09.
  47. ↑ "Cost of Summer AP1000s increases". World Nuclear News. 3 October 2014. Retrieved 6 October 2014.
  48. ↑ “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
  49. ↑ novinite.com - Bulgaria Seeks US Technology for New Unit of Kozloduy NPP
  50. ↑ Tsolova, Tsvetelia (11 December 2013). "UPDATE 1-Bulgaria to start talks with Toshiba over new nuclear unit". Reuters.
  51. ↑ standartnews.com
  52. ↑ novinite.com - Bulgaria, Westinghouse Ink Deal on Kozloduy NPP
  53. ↑ "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
  54. ↑ 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
  55. ↑ "First AP1000 at Moorside online by 2024, Westinghouse says". Nuclear Engineering International. 14 January 2014. Retrieved 15 January 2014.
  56. ↑ "Office for Nuclear Regulation New nuclear reactors: Generic Design Assessment Westinghouse Electric Company LLC 1OO® nuclear reactor" 14 December 2011

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