DISPOSAL OF HIGH-LEVEL RADIOACTIVE WASTE IN DEEP BOREHOLES IN SALT

摘要

For disposal of high-level radioactive waste in rock salt two techniques are available, viz.rnthe mine repository and deep boreholes, drilled from the surface. This paper deals withrnthe second, less-known technique. Firstly the technique as it can be used for permanentrndisposal is described. Subsequently the feasibility to incorporate the option of wasternretrieval is investigated. To this end a number of modifications are proposed: installationrnof casing over the entire borehole length, decrease of the disposal interval andrnemplacement of a special sealing plug at the top of the borehole. Furthermore attention isrngiven to a number of aspects and phenomena important in connection with wasternretrieval, such as cementing, waste-canister protection and convection in the borehole.rnFinally the actual waste retrieval and the abandonment and sealing of the borehole arerndiscussed. The main conclusion of the paper is that disposal of canisters with high-levelrnwaste in deep boreholes can be carried out in such a way, that retrieval of the of wasternduring a limited time period remains possible.