HC Deb 09 July 1997 vol 297 cc483-4W
Mr. Matthew Taylor

To ask the President of the Board of Trade if she will take steps to ensure that Euratom does nto impede the work of the IAEA in carrying out its verification inspections. [6402]

Mrs. Roche

My Department will continue to work closely with the IAEA and Euratom in order that nuclear safeguards inspections are undertaken in an effective and cost efficient manner which enables each inspectorate to draw its own independent conclusions.

Mr. Taylor

To ask the President of the Board of Trade what is the minimum quantity of fissile material that would be required for a criticality in an underground nuclear waste repository. [6403]

Mr. Battle

The minimum quantity of fissile material required for criticality in an underground nuclear repository would be the same as that in any other nuclear facility. This quantity is dependent on a number of factors including the geometry of the fissile material, the presence of moderating materials which reduce the velocity of neutrons, the presence of reflecting materials retaining neutrons within the system, and the presence of materials such as uranium-238, iron, and calcium, which absorb neutrons.

Limits and conditions of authorisation for any repository being developed in the UK would be based on "Guidance on Requirements for Authorisation" which has been issued by the Environment Agencies. This states that a developer would "need to demonstrate that the possibility of a local accumulation of fissile material such as to produce a neutron chain reaction is not a significant concern." This would be achieved by e.g. the establishment of fissile material limits on waste packages, constraints on packaging, provision of backfill and the maintenance of a high pH to suppress the solubility of plutonium.