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The Crystal River 3 Nuclear Power Plant, also simply called the ''Crystal River Nuclear Plant'', is a closed nuclear power plant located in Crystal River, Florida. The power plant is the third plant built as part of the Crystal River Energy Complex which contains a single pressurized water reactor, while sharing the site with four fossil fuel power plants. The Crystal River reactor has been offline since September 2009 when a refueling and 20% uprate outage began. During the upgrade, workers discovered a gap in the concrete containment dome. The NRC investigated and found that the gap was caused by workers applying more pressure to the concrete than it could handle while cutting a hole through which to replace the steam generators. (Taking the generators into the containment through the equipment hatch was not an option as there was no room to maneuver the generators inside the hatch). The plant had originally been due to restart in April 2011, but the project encountered a number of delays.〔(【引用サイトリンク】title=Progress analysing Crystal River repair proposals )〕 Repairs were unsuccessful, and in February 2013 Duke Energy announced that the Crystal River Nuclear Plant would be permanently shut down.〔(【引用サイトリンク】title=Crystal River Nuclear Plant to be retired; company evaluating sites for potential new gas-fueled generation )〕 The coal-fired units are not affected.〔(【引用サイトリンク】url=http://www.cfnews13.com/content/news/cfnews13/news/article.html/content/news/articles/bn9/2013/2/5/duke_energy_shuts_do.html?cmpid=breaking )〕 Crystal River was originally owned by Florida Progress Corporation (and operated by its subsidiary, Florida Power Corporation) but, in 2000, it was bought by Carolina Power & Light to form the new company, Progress Energy, which currently operates the plant. Progress Energy owned 91.8% of the plant; the remainder is owned by nine municipal utilities. Effective July 2, 2012 Duke Energy purchased Progress Energy and made it a wholly owned direct unit of Duke Energy.〔http://finance.yahoo.com/news/duke-energy-acquires-progress-energy-184514127.html〕 ==Outage, repairs and closure== Crystal River is a pressurized water reactor that normally produces 860 MWe, but it has been offline since September 2009 when a refuelling and 20% uprate outage began. While the reactor was down, the old steam generators were to be replaced. There are 426 steel ''tendons'' within the concrete walls of the reactor containment dome which reinforce the dome. Plan developer Sargent & Lundy specified that 97 tendons be loosened. Progress rejected that number as excessive. The next proposal was 74 tendons, which was typical of other nuclear plants doing the procedure. According to a Progress employeee, "de-tensioning the tendons is a very expensive and time-consuming effort", so the number was further reduced to 65. Progress engaged Bechtel to provide a 3rd party review, which agreed that 65 was appropriate. However, when the work was performed, only 27 tendons were loosened, and a foreman and supervisor sent emails questioning the way the tendons were loosened. When workers began to cut the access hole for the steam generators, a crack formed. That crack was repaired, but more cracks appeared. Engineers noticed that parts of the concrete had delaminated. This was repaired, and the concrete re-tensioned, but the same problem was found in other areas. The plant had originally been due to restart in April 2011 following the uprate, but in June 2011 Progress Energy said that it did not expect it to restart until 2014. Preliminary cost estimates for the repairs was put at between $900 million and $1.3 billion,〔 but this estimate was later called into question by Duke Energy.〔http://www.tampabay.com/news/business/energy/repair-costs-rise-at-crystal-river-nuclear-plant/1243770〕 In October 2012 an independent review estimated the repair cost at $1.5 billion, with a worst-case scenario of $3.4 billion. In February 2013 Duke Energy announced that Crystal River would be permanently shut down and that they will recover $850 million in insurance claims.〔 A Duke spokesperson stated, "The company sought input from numerous engineering experts — internally and externally — and used proven industry-accepted practices when determining how to replace the steam generators. Analysis has shown that the 2009 delamination (cracking) could not have been predicted. The U.S. Nuclear Regulatory Commission confirmed these findings."〔 Gregory Jaczko, former chairman of the Nuclear Regulatory Commission, stated, "That's a multi-billion dollar asset that had to be shut down because of improper work planning, improper understanding of how to properly do this containment retrofit".〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Crystal River 3 Nuclear Power Plant」の詳細全文を読む スポンサード リンク
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