Linear Programming Approach for Optimization of Radionuclide Loading in Vitrified HLW

A linear programming approach has been developed to determine maximum mass loading of radionuclides in vitrified high-level waste (HLW). Linear approximation for the centerline temperature of vertically stacked cylindrical HLW canisters has been developed by assuming constant heat flux from a canister, steady-state heat transfer, natural convection, and by neglecting radiation effects. With the linear formula for the centerline temperature, it has been demonstrated that maximum radionuclide mass loading can be determined by the linear programming model conservatively. A numerical result for vitrification of HLW from PUREX reprocessing of pressurized water reactor spent fuel indicates that the maximum temperature constraint is one of the essential constraints in determining the feasible solution space for optimization if the heat emission from the waste is in a certain range (between 11.2 and 24.5 W/kg in this example).

The linear programming model can be utilized to link various fuel cycle models and repository performance models in a consistent and quantitative manner.