Effect of carbonate concentration on the dissolution rates of UO and spent fuel; A Review

Kitamura, Akira  ; Akahori, Kuniaki*

The Japanese geological disposal program has started researching disposal of spent nuclear fuel (SF) in deep geological strata as an alternative management option other reprocessing followed by vitrification and geological disposal of high-level radioactive waste. One of the key parameters for SF disposal other than the disposal of high-level radioactive waste is the fuel dissolution rate. Carbonate concentration in the simulated water composition with contact to SF after canister breaching in the Japanese SF disposal system is around 10 mol dm, which is one order of magnitude larger than those in some countries in Europe. The SF dissolution rate will be depend on carbonate concentration due to promoting oxidative dissolution of SF by formation of carbonate complexes of uranium(VI). For evaluation of reliable SF dissolution rate in the Japanese SF disposal system as an alternative management option, effect of carbonate concentration on dissolution rate of UO and spent fuel has been reviewed.