§ Mr. Llew Smith
To ask the Secretary of State for Foreign and Commonwealth Affairs, pursuant to his oral answer to the hon. Member for Carshalton and Wallington (Mr. Brake), of 18 May 1999,Official Report, column 861, on MOX shipments to Japan, by what means the plutonium in MOX fuel is destroyed in nuclear reactors; and if he will list the evidence on which he based his reply. 
§ Mr. Hoon
Typically, MOX fuel contains between 50 and 70 kilograms of plutonium for each tonne of fuel entering the reactor. It is estimated that after four years of generating electricity, the amount of plutonium remaining in the fuel would have been reduced by about 18 kilograms in each tonne. This underpins the view that the use of MOX fuel reduces proliferation risks by gradually reducing plutonium stockpiles.
This is supported by an OECD (Nuclear Energy Agency) study ("Management of Separated Plutonium: The Technical Options", OECD, Paris 1997) which has indicated that if MOX fuel is burnt at reasonable levels, the world's stockpile of plutonium can be held steady and then gradually reduced during the first decade of the next century.