Post-containment performance of geological repository systems: source-term release and radionuclide migration in the near- and far-field environments

Abstract: This chapter describes the processes that will occur in the nearfield and far-field environments after container corrosion and the ingress of water within the container. This stage will be dominated by the slow, progressive alteration of the waste form and the subsequent release of radionuclides first in the near-field environment, followed by migration towards the geological environment. This chapter describes the processes governing the long-term alteration of the different waste forms, including spent fuel, and the anticipated alteration rates. It then discusses the processes governing radionuclide migration in porous media such as those encountered in the near and far fields of a repository. Conclusions are drawn about the key radionuclides that dominate the long-term impact of a potential deep repository.