An appeal for "alternative approaches" to managing plutonium has come from the UK's Nuclear Decommissioning Authority, despite extensive consultations on the matter and ongoing support for its inclusion in MOX fuel. The Prism reactor concept was offered last year as one such option.
The UK has about 100 tonnes of plutonium that has been separated during the reprocessing of used nuclear fuel over several decades. Plutonium is a fuel that can be recycled in a nuclear reactor to produce more electricity, and this is one reason that the country established infrastructure for this so-called 'back-end' of the nuclear fuel cycle.
However, the UK's experiment with fast reactors that could have used the plutonium was not a commercial success and interest in a 'plutonium economy' waned to the point that Britain began to look at the plutonium stocks as a 'zero value asset'. Nevertheless, the stocks must either be conditioned and disposed of as waste, or manufactured into some kind of reactor fuel that can be used up.
Several options spanning these choices were drawn up starting in 2007, all representing a net financial outlay, although some mitigate this with power generation or sales of MOX fuel. After presenting these in public consultations the government declared in December 2011 a "preliminary view" that combining the plutonium with uranium in mixed-oxide (MOX) fuel for conventional reactors was the "best available option."
The UK government described MOX as "the most credible and technologically mature option" but added that it "remains open" to other ideas should they "offer better value or less risk for the taxpayer."
Britain has a chequered history of MOX production, with many years of poor performance at the Sellafield MOX Plant that recycled plutonium for foreign customers from their used nuclear fuel. Although this had been on an improving trajectory and a new production line was planned, the plant was forced into closure last year when its Japanese customers cancelled orders five months after the Fukushima accident amid the still on-going reactor shutdowns.
The NDA has now issued an invitation for expressions of interest in development of alternatives. It said it wanted to "gather more data on other options" and that it was talking with the government and third parties to review "whether alternative technologies may represent credible options" over a timescale of about 25 years.
One obvious example of a different technology would be an advanced reactor that could generate electricity from the plutonium - as GE-Hitachi Nuclear Energy proposed in London at the very end of the previous consultation.
The company was promoting its Prism reactor concept and offering to support the development of a small power plant with two 311 MWe fast reactors. These would irradiate fuel made from the UK's plutonium stocks and bring it to a form suitable for disposal after 45-90 days, working through the entire stockpile in five years. More commitment to the Prism concept could see it re-using the conditioned fuel solely for electricity generation, operating for up to 60 years in that mode of operation.
In October 2010, GEH and Savannah River Nuclear Solutions - a partnership between Fluor, Northrop Grumman and Honeywell - signed a memorandum of understanding to consider constructing a prototype Prism reactor at the US Department of Energy's Savannah River site in South Carolina. It would be built as part of a proposed demonstration of small reactor technologies.
Researched and written
by World Nuclear News