The Effect of Ln(III)/An(III) Separation on Feasibility of TRU Recycling in PWRs

This work examines the effect of recycling Ln(III) fission products together with An(III) TRU in existing PWRs without separating them as commonly assumed. TRU recycling in three different fuel forms was studied: U-MOX, Th-MOX, and Fertile Free Fuel. We analyzed the effect of Ln(III) separation on fuel cycle length, efficiency of TRU destruction, and the core reactivity feedback coefficients. Two-dimensional transport and fuel assembly burnup code BOXER was used for the analysis. The full core characteristics were approximated through the use of Linear Reactivity Model. The results show that separation of Ln(III) from An(III) is not mandatory but results in significant deterioration of the PWR core characteristics: Larger TRU loading, reduced control materials reactivity worth, reduced TRU burning efficiency, and less favourable reactivity feedback coefficients. However, the decision on whether to recycle or to separate Ln fission products should be based on comprehensive comparison of the costs associated with each option.