Effect of ionizing radiation on waste package performance in a basalt high level waste repository

Current data are presented on the effect of ionizing radiation on the performance of the waste package in the proposed high level waste repository in the Columbia River basalts. The potential of ionizing radiation to alter chemical and geochemical processes has been well established. The primary mechanism is the formation of radiolytic species which will affect the transport of radionuclides, their speciation, the stability of the packing and container corrosion. These effects are not additive and must be integrated into the performance models developed for the waste package. Ionizing radiation will have the most impact on the performance of the waste package since radiation levels are highest there. The coupling of radiolytic processes with geochemical/chemical processes in basalt groundwater/packing waste form systems is being investigated as part of an ongoing effort in the Basalt Waste Isolation Project (BWIP). Of primary concern are the effect of radiation on the composition of the groundwater, redox environment, packing alteration, pH and formation of organic polymers