In the frame of the Safety and Feasibility Case 1 development in Belgium, the Belgian agency for radioactive waste (ONDRAF/NIRAS) has to demonstrate that the geological disposal of (vitrified) High-Level Waste (HLW) and Spent Fuel (SF) in the Boom Clay host rock following the Supercontainer design provides sufficient safety. This safety relies on the containment of the radionuclides by the overpack, the retardation of radionuclide release from the waste matrix, the diffusion controlled transport of the radionuclides, and their low solubility and sorption on the Boom Clay host rock. This paper presents the arguments that support the safety contribution of the retardation of radionuclide release by the fuel matrix (the source term) in Supercontainer conditions, characterized by the presence of a thick concrete buffer and hyperalkaline pore water. This includes a phenomenological description of the expected evolution, a description of the fuel alteration mechanisms and model, and a selection of reference fuel matrix alteration rates and effective surface areas for use in the performance assessment calculations of Safety and Feasibility Case 1.
|Name||MRS Symposium Proceedings|
|Conference||XXXV International Symposium "Scientific Basis for Nuclear Waste Management”, MRS 2011|
|Period||2011-10-02 → 2011-10-07|