NATURAL RADIONUCLIDE FLUXES AND THEIR CONTRIBUTION TO DEFINING LICENSING CRITERIA FOR DEEP GEOLOGICAL REPOSITORIES FOR RADIOACTIVE-WASTES

An assessment has been performed of the viability of using fluxes of n atural elements and radionuclides as a basis for defining allowable re leases to the biosphere from a radioactive waste repository. The mass fluxes and radioactive fluxes of elements and radionuclides due to gro undwater transport, glacial erosion and non-glacial weathering in the vicinity of the Aspo Hard Rock Laboratory, Sweden, were quantified and compared to proposed Swedish limits for biosphere releases from a spe nt-fuel repository. This study has demonstrated that it is possible to calculate fluxes of naturally-occurring radionuclides that are direct ly comparable to performance assessment predictions of repository flux es to the biosphere. Since the radiological impact of natural fluxes o f radionuclides is broadly understood and since natural and repository fluxes can be assessed on a comparable basis, this suggests that natu ral fluxes can be used as criteria for defining long-term indicators o f repository safety.