The Effect of PWR Fuel Management Strategy on DUPIC Fuel Cycle

Abstract

In the DUPIC fuel cycle, spent PWR fuel is recycled directly into CANDU reactors. Because of evolving fuel management strategies, the spent PWR fuel composition is expected to be different from one cycle to the next. Variations in reload fuel enrichment, loading patterns, and batch sizes, can thus result in nominal DUPIC core performance that will vary. In order to evaluate the sensitivity of the DUPIC fuel cycle on PWR fuel management strategy, we have made a preliminary study based on the linear reactivity model. A generic study ofDUPIC fuel was then carried out by DRAGON/OPTEX-4/DONJON with ENDF/B-V library, for various spent PWR fuel types. The initial enrichment in PWR varied from 3.2 w/o to 4.5 w/o with the discharge burnup ranging from 30000 MWD/T to 52000 MWD/T. Our 3D full core calculations show that all nominal DUPIC cores have similar peak power, adjuster worth, CPPF, even similar average exit burnup regardless of initial enrichment in PWR fuel. It was found that the total discharge burnup of the tandem cycle (PWR+CANDU) is constant for the nominal DUPIC fuel cycle with a given initial enrichment in PWR. The increase in total burnup is entirely attributable to the PWR leg of the tandem cycle. This implies that the DUPIC fuel cycle may not be economical beyond a certain initial enrichment in PWR because of the fixed discharge burnup in CANDU and the rapidly increasing DUPIC fuel fabrication costs associated to the radioactivity of the spent PWR fuel.