Meanwhile owning 118 tonnes of plutonium is an ever-more-expensive problem. It is a volatile substance constantly in a state of radioactive decay that can be stored only in small separated amounts to keep it from reacting with itself, a process called "going critical."
A specially built new store has just been commissioned at Sellafield. The annual costs of looking after this much plutonium are currently estimated at £80 million a year.
The government is convinced that one day it will be an asset despite all the evidence to the contrary. It is waiting for the Nuclear Decommissioning Authority, a quasi-autonomous watchdog charged with dealing with waste and "end products" of the nuclear industry, to come up with a solution.
Three options under consideration are new versions of failed technologies. Two involve building a new MOX plant to create a new sort of fuel to burn plutonium and uranium in either Canadian reactors or yet-to-be-built British ones. Both require large investments by British taxpayers, about £6 billion.
The third option is a new fast-breeder reactor, different from the old failed type, or so its proposers claim. The GE Hitachi Prism reactor, to be developed by the Japanese, would burn plutonium and also produce new fuel for other reactors. Not yet built, in theory it will work, and its proposers say they will bear the cost of construction.
The Decommissioning Authority says it will come up with a preferred option on what to do with the plutonium soon, burning it as fuel or disposing of it as waste, and then the government will have to decide.
Campaigners against the UK nuclear industry believe none of the schemes to use plutonium as fuel will work, and that by taking ownership of other countries' stockpiles Britain is making a bad situation worse.
Martin Forwood, of Cumbrians Opposed to a Radioactive Environment, said successive governments had pledged to ensure that plutonium belonging to foreign governments would be returned to them. Now, as these governments had abandoned using their plutonium as fuel, the UK had agreed to take it.
"Britain is being used as a plutonium dumping ground," he said. "All those promises and the contracts saying the waste and plutonium would be returned to the country of origin have been put on one side. It is a disgrace."
As for using plutonium as a fuel, he said: "Lessons have clearly not been learned from the UK's past MOX mistakes, which have already cost the taxpayer a fortune. Common sense dictates the government and the NDA should treat plutonium as waste and put it out of harm's way once and for all."
Adrian Simper, the NDA's strategy and technology director, seemed pleased at what he called the "market tension" of alternative ways of using the plutonium. He told the London Financial Times the intention was to tell the government whether there were "three, two, one – or even no ways forward." At some point it would have to decide the fate of the plutonium.
This article originally appeared at The Daily Climate, the climate change news source published by Environmental Health Sciences, a nonprofit media company.