§ Mr. Arthur Lewisasked the Secretary of State for Energy how and why 15,400 lbs. of toxic uranium products have been lost; why for the second year running several tons of natural uranium worth £40,000 a ton is missing; whether such proven lapses of security could happen regarding radioactive materials; and whether he will make a statement.
§ Mr. Norman LamontThe hon. Member asked about apparent loss of nuclear material in the United Kingdom. Annual figures for "Material Unaccounted For" (MUF) in the United Kingdom back to 1970 have been published by the United Kingdom Atomic Energy Authority and British Nuclear Fuels Ltd. The figures for the year 1978–79 have just been released.
Accounts of nuclear materials are maintained at all nuclear sites in the United Kingdom. At intervals, comparisons are made between their physical and "book" inventories. The arithmetical difference between these two inventories is the "Material Unaccounted For". This difference is sometimes positive, indicating an apparent "gain", and sometimes negative, indicating an apparent "loss". The occurrence of positive MUF figures does not mean that material has in some way been created; similarly, a negative MUF figure does not signify an actual loss of material. The apparent losses of uranium appearing in this year's MUF figures are not out of line with the fluctuations between apparent losses and gains reported in previous years. These fluctuations arise from the unavoidable uncertainties of measurement. UKAEA and BNFL are actively engaged in research to improve their measurement techniques, but it is not to be expected that MUF can be eliminated.
It is not the case that these "accounting" figures indicate a real loss, nor that they represent "proven lapses of security". The amount of uranium unaccounted for represents less than one half of 1 per cent. of the annual throughput at the plants concerned.
There is no evidence whatsoever of any deficiency in the physical security measures in force at the sites, which are designed to ensure that nuclear material is not stolen. The measurements of 621W nuclear material leaving UKAEA and BNFL sites are sufficiently precise to ensure that the accidental discharge of material would be detected.