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, containers 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 analysis 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 approach, representing an alternative to the common concepts, can be safer and cheaper. It takes the HIPOW copper canister as the only major barrier and a cheap but sufficiently efficient buffer as embedment. The repository can consist of an abandoned copper mine, an option being to place HLW in emptied drifts while mining is still going in not yet exploited parts of the ore body.