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The Wylfa Nuclear Power Station ((ウェールズ語:Atomfa'r Wylfa)) is situated just west of Cemaes Bay on the island of Anglesey, North Wales. Its location on the coast provides a cooling source for its operation. Wylfa houses two 490 MW Magnox nuclear reactors, "Reactor 1" and "Reactor 2", which were built from 1963 (making Wylfa the world's oldest operating nuclear power station by date of construction) and became operational in 1971. Reactor 2 was retired in 2012; Reactor 1 is licensed to operate until 31 December 2015.〔(Inter-reactor fuel transfer at Wylfa 1&2 )〕〔 ==History== The construction of the power station, which was undertaken by British Nuclear Design & Construction (BNDC), a consortium backed by English Electric, Babcock & Wilcox Ltd and Taylor Woodrow Construction,〔(Nuclear Development in the United Kingdom )〕 began in 1963. The reactors were supplied by The Nuclear Power Group (TNPG) and the turbines by English Electric. It was the second nuclear power station to be built in Wales, after Trawsfynydd. Following the closure of Trawsfynydd in 1991, Wylfa is the only nuclear power station in Wales. Wylfa houses two 490 MW Magnox nuclear reactors, "Reactor 1" and "Reactor 2", which were built from 1963 and became operational in 1971.〔(Nuclear Power Plants in the UK - Scotland and Wales )〕 Wylfa typically supplied 23 GW h of electricity daily when they were both in service. These were the largest and last Magnox-type reactors to be built in the UK. Wylfa was the second British nuclear power station, following Oldbury, to have a pre-stressed concrete pressure vessel instead of steel for easier construction and enhanced safety. The original design output was 1,190 MW but unexpected accelerated ("breakaway") corrosion of mild steel components of the gas circuit in hot CO2 was detected even before the first reactor began operating. The channel gas outlet temperature, the temperature at which the CO2 leaves the fuel channels in the reactor core, had to be reduced, initially dropping the power output to 840 MW, which was later raised to 980 MW as more experience accumulated. The graphite cores each weigh ; 6,156 vertical fuel channels contain over 49,248 natural uranium magnox-clad fuel elements, hence the name magnox reactor. A further 200 channels allow boron control rods to enter the reactor and control the nuclear reaction. The primary coolant in the reactors is carbon dioxide gas. The power station is operated by Magnox Ltd, formerly Magnox North, formerly British Nuclear Group, formerly Magnox Electric, formerly Nuclear Electric, formerly National Power, formerly the Central Electricity Generating Board (CEGB). The site is owned by the Nuclear Decommissioning Authority (NDA). Its purpose is to oversee and manage the decommissioning and clean-up of the UK's civil nuclear legacy. During its operational life substantial works have been needed to strengthen the reactors against deteriorating welds discovered in the safety review in April 2000. Amid public controversy, Greenpeace issued an independent safety appraisal〔(Review of ageing processes and their influence on safety and performance of Wylfa nuclear power station ), Greenpeace〕 by the nuclear engineering consultancy Large Associates, but the permit to restart operation was given in August 2001. In addition to welding weaknesses, radiolytic depletion of the graphite moderator blocks was still of concern and PAWB continue to campaign for early shut-down of the plant as well as against any nuclear replacement. On 20 July 2006 the NDA announced that the station would be shut down in 2010 to enable the closure and decommissioning of the Magnox spent fuel reprocessing plant at Sellafield. Springfields Fuels Limited ended production of Magnox fuel elements in 2008 due to these plans. However, in 2010 the NDA announced an extension to 2012, beyond Wylfa's 40th anniversary as a generating power station in January 2011, due to schedule slippage at Sellafield which would allow Wylfa additional time before final defuelling. At this time, a strategy was also devised to maximise the generation from the remaining fuel stock given that new fuel could no longer be manufactured. This required a change in the distribution of fuel within the reactors, as well as a the closure of Reactor 2 in 2012 to allow this fuel to be transferred into Reactor 1. Reactor 2 ceased generating on 25 April 2012 at 19:02 BST, allowing Reactor 1 to continue to operate. A license extension to operate Reactor 1 until 31 December 2015 was granted in September 2014.〔(Wylfa nuclear plant given extension )〕 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「Wylfa Nuclear Power Station」の詳細全文を読む スポンサード リンク
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