§ Mr. Rostasked the Secretary of State for Energy whether he is yet in a position to give up-to-date figures for the rate of plutonium production in the fuel of the electricity generating boards' Magnox, advanced gas-cooled reactors and pressurised water reactors.
§ Mr. Giles ShawThe following figures are based on fairly typical current or design operating conditions:
(1) (2) Tonnes total plutonium per GWey generated (net)* (3) Per cent. Pu-239 Magnox 0.80 60–80 AGR 0.25 50–60 PWR 0.30 55–60 * ie for a station operating continuously at 1000 MW(E) for a year. Notes:
1. The above figures are based on the assumption that 1000 MW(E) is sent out—that is after deduction of any electricity consumed at the station for operational or site purposes. This "net" basis is that commonly used in statistics published by the United Kingdom generating boards.
2. The production of plutonium per annum in any particular station is affected by the fraction of the year in which that station operates, its level and mode of operation, fuel irradiation history and other features of the design and operating regime. Estimates in terms of plutonium produced per unit of electricity are also affected by the thermal efficiency of the station.
3. The isotopic composition of the plutonium produced varies significantly with fuel design and management and in particular the irradiation of the discharged fuel. None of the boards' separated plutonium in stock with British Nuclear Fuels Ltd. has a Pu-240 content of less than 15 per cent.
4. In order to calculate future arisings of plutonium for planning purposes an assumption must be made about average availability expressed as the proportion between the amount of electricity expected to be generated in a given year, and the amount that would have been generated had the station been assumed to be run continuously for that year at its planned capacity.