Optimal ways of disposal of highly radioactive waste

Abstract

Multibarrier concepts are commonly proposed for effective isolation of highly radioactive waste (HLW). Present concepts consider the host rock as a barrier by retarding migration of possibly released radionuclides to the biosphere, con-tainers for preventing release of radionuclides, and " buffer clay " embedding the canisters for providing ductility and minimizing the risk of container breakage and for delaying migration of possibly escaping radionuclides. Closer ana-lysis of the isolating functions shows that rock will only serve as a mechanical protection of the " nearfield " , the containers of proposed types can be short-lived, and the surrounding clay will be increasingly permeable and stiffen hence becoming less ductile with time. A different ap-proach, representing an alternative to the com-mon concepts, can be safer and cheaper. It takes the HIPOW copper canister as the only major barrier and a cheap but sufficiently effi-cient buffer as embedment. The repository can consist of an abandoned copper mine, an option being to place HLW in emptied drifts while min-ing is still going in not yet exploited parts of the ore body.