Assessing the long-term behavior of a radioactive waste disposal tunnel with a damage model incorporating chemical degradation effects

Kobayashi, Akira*; Chijimatsu, Masakazu*; Fujita, Tomoo ; Yamamoto, Kiyohito*

To examine the effect of the degradation of rock on the behavior of near field of the repository of high-level radioactive waste disposal, the degradation of rock was examined by submerging the rock sample into saline water for 90 days. By using the damage parameters obtained from the degraded sample, the behavior of the near field was simulated with the varying boundary conditions for one million years. The model used for the analysis was called the damage expansion model considering the volumetric expansion due to damage. It was observed from the analyzed results that the damage would be developed locally at the spring line and crown of repository tunnel. After about one hundred years, the damage evolution would be finished even if the degradation progressed so much.