OPTIONS FOR THE FUTURE MANAGEMENT OF THE INTERMEDIATE-LEVEL WASTE SHAFT AT DOUNREAY

The Dounreay intermediate level waste (ILW) shaft was constructed duri ng the 1950s as part of the excavations for the low level liquid efflu ent discharge system. It was licensed as an ILW disposal facility by t he Scottish Office in 1959 and was used routinely from 1960 to the ear ly 1970s for the disposal of unconditioned ILW wastes. It was used inf requently thereafter. In May 1977, an explosion took place in the gas space above the waste column and since that time the facility has been under a care and maintenance regime. Although the shaft is a licensed disposal facility, the United Kingdom Atomic Energy Authority (UKAEA) considers that it does not represent an acceptable model for ILW disp osal. In 1996 it was decided to revisit the earlier supposition that r etrieval was not practicable and an initial ser ies of option studies was commissioned. Following the successful conclusion of this work, a further series of more exhaustive studies was undertaken and these con cluded in August 1997. UKAEA is now assessing the results of the studi es and has committed to making a proposal to Government by the end of 1997 on the future management of the shaft. This paper describes the s tudies undertaken and presents, in summary form, their results.