MOVEMENT OF A REDOX FRONT AROUND A REPOSITORY FOR HIGH-LEVEL NUCLEAR WASTE

The evolution and formation of a redox front in the nearfield of a rep ository for high-level nuclear waste is modeled, considering the effec t of a time-dependent source term of the oxidizing species produced by radiolysis of the water entering the canister. The transport of oxida nts in the clay surrounding the canister occurs by diffusion. In the r ock, the transport of oxidants is modeled as occurring through fractur es, with diffusion into the rock matrix. The results show that it is n ot probable that the redox front will ever move past the bentonite. If if does, the tips of the redox front may move <100 m over a million y ear period in a channel with a high flow rate.