第三百八十三段 「セラフィールドMOXプラント閉鎖」の報で思った由無し事


World Nuclear Newsのサイトでは、8月3日付で以下のように報じている。

The manufacture of mixed oxide (MOX) nuclear fuel at Sellafield is to stop "at the earliest practical opportunity" to reduce the financial risks to British taxpayers from events in Japan.

The closure comes as a result of the Fukushima accident, which dramatically increased uncertainty for the ten Japanese utilities that had placed contracts for supplies of MOX fuel. This is made by combining uranium with plutonium recovered by reprocessing used nuclear fuel.

The Nuclear Decommissioning Authority (NDA), which owns all the UK state's nuclear assets, said it reviewed the risk profile for operation of Sellafield MOX Plant (SMP) and "concluded that in order to ensure that the UK taxpayer does not carry a future financial burden from SMP that the only reasonable course of action is to close SMP at the earliest practical opportunity."

Separately Areva last week announced the cancellation of orders for uranium and nuclear fuel amounting to €191 million ($273 million) as a result of the shutdown of reactors in Japan and Germany.

The NDA's move to close SMP will be a grave disappointment for the plant's 600 workers, who had celebrated success in raising performance to commercially acceptable levels. Despite being designed to produce 120 tonnes of fuel per year, it never operated properly and was downrated to just 40 tonnes per year. In its nine years of operation to 2010 it produced only 15 tonnes of fuel.

However, in 2010 the NDA and ten Japanese utilities agreed on a plan to refurbish the SMP "on the earliest timescale" using technology from France's Areva. A new rod manufacturing line was being installed which, as well as improving overall performance, was meant to ultimately replace the existing one.

The NDA's Sellafield site - including the SMP - is managed by Nuclear Management Partners, a consortium of URS of the USA, AMEC of the UK and Areva of France.

Taking the back-end forward

The two major elements in the UK's strategy for the back-end of the nuclear fuel cycle were SMP and the Thermal Oxide Reprocessing Plant (Thorp), at which used nuclear fuel is reprocessed to separate uranium and plutonium from wastes that go on to be vitrified ready for permanent disposal.

A document released in March 2010 highlighted that Thorp would require refurbishment or replacement to handle the complete inventory of used nuclear fuel it was built to process - all that coming from the fleet of Advanced Gas-cooled Reactors (AGR) as well as international contracts. Some 6600 tonnes of AGR fuel remains outstanding, with options for storing it unclear until a permanent repository is available in about 2030.

Simultaneously, the UK is considering the future of some 100 tonnes of civil plutonium, which is currently classified as a 'zero value asset'. A public consultation on this ran from February to May.

In late March the former science advisor to Tony Blair, Sir David King, presented a range of options which in essence showed it makes sense to produce MOX fuel from the plutonium. The question for the UK is whether it wants to offset the cost of this with extra savings and revenues from the potentially expensive return to the full nuclear fuel cycle that would come with a refurbishment of Thorp.

A cost-benefit analysis of a new MOX plant has been commissioned by the Department of Energy and Climate Change and a decision based on that is expected before the end of this year.

要は、 福島第1原発事故の発生により同プラントにとって最大の顧客である日本のプルサーマル計画の先行きが不透明となったことで、プラント運営に当たって将来的に納税者負担が発生する可能性が高まったことを受け、負担が現実化する前に英原子力廃止措置機関が”可及的速やか”なプラント閉鎖を決定したというもの。







・World Nuclear News 「Sellafield MOX plant to close 」 2011年8月3日
・World Nuclear News 「Chinese fast reactor starts supplying electricity 」 2011年7月21日
・東西貿易通信社 「East & West Report」No.11029 2011年8月1日