LONDON - A civilian nuclear fuels reprocessing plant in Cumberland cannot account for some 30 kilograms (66 pounds) of plutonium, enough for seven or eight nuclear bombs.
The annual audit of nuclear material at all of Britain's civil nuclear plants is expected to reveal that the quantity of plutonium at Sellafield was classified as "material unaccounted for" last year, The Times newspaper said Thursday.
Figures published by the British Nuclear Group (BNG) each year reveal an audit of nuclear material which is admitted and processed by the various plants nation-wide.
A spokeswoman at Sellafield said: "This is material that is unaccounted for, and there is always a discrepancy between the physical inventory and the book inventory. There is no suggestion that any material has left the site."
The Sellafield spokeswoman, quoted by the Press Association newswire, said the most likely reason for any shortfall was due to the complex measuring processes that are carried out.
Asked if the 30 kilogram figure raised concern, she replied: "I wouldn't say we would be alarmed by it, because we are only talking about a book figure here."
Guidelines issued by the International Atomic Energy Agency (IAEA) say that material unaccounted for must not exceed three percent of the amount that is processed.
If the 30 kilogram figure is accurate, it would equate to around 0.1 percent of that amount, the spokeswoman said.
A spokesman for the Department of Trade and Industry said: "This is an account of an ongoing process and does not represent the loss of any actual material.
"It is not unusual for the accounting process to indicate material unaccounted for."
But independent experts were worried about the disclosure, according to the Times.
"They make this claim of an auditing problem but I would expect them to be overzealous in the current climate of fears about terrorism," John Large, an independent nuclear consultant, was quoted as saying.
Frank Barnaby, a specialist in nuclear weapons, told The Times "there will always be some material unaccounted for but this is a dramatic development."
Spent nuclear fuel rods, which have been inside nuclear reactors for about five years, are taken to Sellafield for reprocessing.
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