Britain's Policies on Fissile Materials: The Next Steps

If and when global nuclear disarmament is embraced, verification would have to become comprehensive. .
             To shift Britain's nuclear institutions from a culture of plutonium separation and accumulation to one of plutonium storage and disposition. This entails recognition that the great majority of plutonium held in Britain is now surplus to any conceivable civil or military requirement. It is a waste, and has to be dealt with as such. .
             To become more active abroad, particularly in co-operation with the US and European allies, in the search for new policy and diplomatic solutions to the problems that currently beset this vital area of international security. .
             2. Britain's acquisition programmes .
             Britain has acquired fissile materials from many sources, domestic and foreign, and for many purposes over the past half century. Although the sizes of its inventories are subject to many uncertainties, the story of their acquisition can now be sketched in some detail. It needs to be recounted because of its importance to an understanding of the current situation. As will become apparent, more is known about Britain's plutonium inventories than about its HEU inventories. .
             2.1 Acquisition of highly enriched uranium for military purposes .
             Britain's first nuclear weapons were implosion devices constructed with plutonium. HEU production began in the mid-1950s with the construction of a gaseous diffusion enrichment plant at Capenhurst in Cheshire. The production of HEU became an imperative when the Macmillan government instructed weapon designers to produce fission bombs that would give high yields when tested. It wished to impress the US with the sophistication of Britain's weapon capabilities, thereby encouraging the US to look more favourably upon co-operation in weapon design. .
             Remarkably, the enormous and costly facility at Capenhurst only operated for five years at anything approaching full capacity before the bulk of the plant was shut down in 1962, by which date between four and five tonnes of HEU could have been produced.