To ask the Secretary of State for Trade and Industry pursuant to the written statement of 20 July 2006, Official Report, column 54WS, on civil plutonium and uranium stocks, if he will clarify the reason for the 200 kg reduction in the quantity of plutonium contained in unirradiated MOX fuel or other fabricated products at reactor sites or elsewhere; in what part of the reprocessing process the plutonium is lost; where it is now; what his definition of down-blending is; and who is responsible for accounting for such materials. (95132)

Further detailed analysis of the Annual Statement has identified that a clerical error occurred in the allocation of material to the appropriate Civil Unirradiated Plutonium category.

This has resulted in the figure for plutonium in unirradiated MOX fuel or other fabricated products at reactor sites or elsewhere being less than it should be. This has not affected the total plutonium holding. Revised figures for the UK's stocks of civil plutonium and uranium will be placed in the Libraries of the House and the Department's website once they have been verified.

The material has not physically moved and has been accounted for on a monthly basis. The material in question is not part of any process losses.

Down-blending is the opposite process to enrichment. Uranium with a high U-235 content is mixed with uranium with a lower U-235 content to give a product with an intermediate U-235 content, which depends on the relevant proportions of the start materials. In this instance high enriched uranium residues, recovered during decommissioning operations at the Capenhurst Gaseous Diffusion Plant, are blended with either low enriched uranium or depleted uranium to give a product containing less than 5 per cent. U-235.

The accounting of such materials is the responsibility of individual site licence companies.