LONDON, Feb 17: A civilian nuclear fuel reprocessing plant in north west England cannot account for enough plutonium to produce seven or eight nuclear bombs , but regulators said on Thursday it was due to bookkeeping errors and no material had left the facility.

"This is material that is unaccounted for, and there is always a discrepancy between the physical inventory and the book inventory," said a spokesman for the British Nuclear Group (BNG) which audited the plant, confirming a report in the daily The Times that some 30 kilograms (66 pounds) of plutonium could not be traced.

"There is no suggestion that any material has left the site," which is located in Sella field, north west England," she added. "When you have got a complicated chemical procedure, quite often material remains in the plant."

The United Kingdom Atomic Energy Authority said there was no reason to believe that "real loss" of plutonium had occurred. "The material unaccounted for 2003-2004 were all within international standards of expected measurement accuracies for closing a nuclear material balance at the type of facilities concerned," it said.

"We have published these figures since the 1970s". Some years there is an apparent gain, some years there is an apparent loss," the BNG spokeswoman said. Figures published by the BNG each year reveal an audit of nuclear material which is admitted and processed by various plants around Britain.

Guidelines issued by the 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 per cent of that amount, the spokeswoman said. A spokesman for the Department of Trade and Industry said: "It is not unusual for the accounting process to indicate material unaccounted for." -AFP