Retrievability of Spent Nuclear Fuel After Final Disposal in a Salt Dome

After closure of a repository, spent-fuel retrieval in a salt dome can be accomplished by either direct access by sinking boreholes or shafts directly into disposal areas or by indirect access by entering former disposal fields via a new retrieval mine. With state-of-the-art technology, salt mining can be carried out up to a rock temperature of 100°C. Calculations performed for a repository design suitable for the Gorleben salt dome show that 100 yr after disposal, large repository zones will be cooled down below 100°C. Thus, a significant part of the spent fuel in such a repository could be retrieved. A detailed study suggests that retrieval would be possible at any time after repository closure with presently available technology.

Because of the massive effort and considerable time required for retrieval - which can be reliably discovered by surface monitoring, e.g., by remote satellite sensing - the diversion of fissile materials by secret retrieval is not a concern and is excluded.