§ Mr. Eadie
Assurance that thefts of nuclear material from the Windscale reprocessing plant can be detected is obtained primarily from rigorous security 133W procedures of which accounting procedures are only one part. These procedures, the nature of the process—involving remote handling behind concrete shields or in glove boxes—and the material accounting systems employed give a high degree of assurance that no material can be removed from the plant undetected. The security arrangements are kept under continuous review. As far as the nuclear material accounting procedures are concerned, the main area of difficulty lies with the accurate measurement of the quantity and plutonium content of the irradiated magnox fuel fed to the plant. The procedures in use give rise to a number of uncertainties and the management is currently examining the possibilities for improvement. It would not be in the public interest to disclose the minimum size of theft that is detectable by means of nuclear material accountancy.
§ Mr. Eadie
Because of the accumulation of Magnox fuel in the Windscale storage ponds, one Calder reactor is being134W partially used as a store so as to help ensure continued ability to accept fuel from the generating boards. At present the reactor contains about 70 tonnes of spent fuel. The arrangement will continue until the storage position has eased. The reactor has not, however, been decommissioned.
§ Mr. Hoyle
asked the Secretary of State for Energy if any discrepancies have been found between the stated amount of nuclear material in any shipment and the actual amount of material for shipment between nuclear installations within the United Kingdom and for international transits to and from United Kingdom.
§ Mr. Eadie
Relatively minor discrepancies between amounts of nuclear material quoted by a shipper and those found by a recipient do occur from time to time. When these differences are significant immediate efforts are made to resolve them by examination of the conditions of measurement. Two measurement situations arise, namely (i) when the data quoted by the shipper is only estimated, as precise measurement is not possible—e.g., irradiated fuel movements—but the receiver is able to convert the material to a measurable state; in this case the receiver's figure is invariably considered to be the best value; (ii) when both shipper and receiver are able to perform weighing, sampling and analysis to determine the nuclear material content of the consignment; if significant differences occur, further measurements are made and, in practice all significant differences have, in fact, been resolved.