The reuse of plutonium as mixed-oxide (MOX) fuel offers the best prospect for the solution to managing the UK's stockpile of plutonium, according to the country's government.
In launching a consultation on the management of the UK's plutonium, the UK Department of Energy and Climate Change (DECC) said that it had considered three options: reuse as MOX fuel; immobilization and direct disposal; and continued long-term storage.
The UK is currently storing about 112 tonnes of civil separated plutonium. This amount includes about 28 tonnes of material belonging to overseas customers. The plutonium stored in the UK has been derived largely from nuclear fuel reprocessing activities that have been ongoing at Sellafield since the 1950s.
"The UK's civil plutonium is housed in safe and secure bespoke facilities at Sellafield and Dounreay pending a final decision on the best long term solution for its management," DECC said. However, "there are currently no final plans on how it should be managed in the long-term."
According to DECC, "If all our plutonium was converted to MOX fuel it would be about enough to power two reactors for about 60 years utilising a 40% MOX core."
However, "the reuse as MOX option would require significant expenditure and construction of a major new plant, but it is based on proven mature technology that could be deployed on a reasonable timescale."
DECC noted, "Successful commercial MOX manufacturing is demonstrated by Areva's plant in France which, with a licensed capacity of 195 tonnes of MOX fuel per annum, has produced 140 tonnes of MOX fuel per annum over the last few years." But "UK experience has been much less successful." The Sellafield MOX Plant (SMP) has only produced some 15 tonnes of MOX fuel in its nine years of operation, compared with an original target of 560 tonnes over an expected ten year operational life. This low throughput is "largely due to its complex design and operating regime."
According to estimates based on Nuclear Decommissioning Authority (NDA) data, the cost of constructing a new MOX fuel plant in the UK and operating it for about 30 years "could be expected to be around £5 to £6 billion ($8 to $10 billion)." However, because the resulting MOX fuel could be worth "in excess of £2 billion ($3 billion) … it could to some extent, offset the cost of its manufacture."
This compares with an estimated cost of between £5 and £7 billion ($8 to $11 billion) to immobilize and dispose of the plutonium. However, DECC noted that this cost "can vary considerably and will ultimately depend on the technology employed."
Meanwhile, the continued long-term storage of plutonium is considered "not an easy low cost option." The estimated cost of storing the plutonium for about 110 years is put at about £8 billion ($13 billion). This option would still require permanent disposal at a future date.
DECC said: "The UK government's preliminary policy view is that proceeding on the basis that reusing plutonium either in the UK or overseas in the form of MOX fuel offers the best prospect to deliver a solution for long-term plutonium management."
However, it added, "This preliminary view will be conditional in that it will have to be tested to show that it is affordable, deliverable and offers value for money, taking into account safety and security requirements, before the UK government will be in any position to take a final view."
"The primary grounds for this decision are that MOX fuel fabrication is a proven and available technology that offers greater certainty of success," according to DECC. It noted that the advantages of this option are that it "allows use of the inherent energy resource of the plutonium and creates a proliferation resistant waste-form that is consistent with existing plans to dispose of used fuel in the UK." In addition, "the costs of disposing of plutonium by this route are of similar estimated costs to direct disposal."
However, it noted, "In the near term the only available option for plutonium management is ongoing storage and this will continue to play a large part in our strategy whilst long-term options are developed. Implementing a final policy for long-term plutonium management will take time."
Lord Marland of Odstock, parliamentary under-secretary of state for energy and climate change, commented: "There are currently no final plans for how the UK's plutonium should be managed in the long-term. It is high time we got to grips with this and developed a coherent and comprehensive plan for dealing with this issue."
He added, "We are keen to assess all the options for affordability, deliverability, value for money, safety and security."
The consultation closes on 10 May 2011.
Researched and written
by World Nuclear News