Conceptual studies for pressurised water reactor cores employing plutonium-erbium-zirconium oxide inert matrix fuel assemblies

The most efficient way to enhance plutonium consumption in light water reac tors is to eliminate the production of plutonium all together. This require ment leads to fuel concepts in which the uranium is replaced by an inert ma trix. At PSI, studies have focused on employing ZrO2 as inert matrix. Addin g a burnable poison to such a fuel proves to be necessary. As a result of s coping studies, Er2O3 was identified as the most suitable burnable poison m aterial. The results of whole-core three-dimensional neutronics analyses in dicated, for a present-day 1000 MW, pressurised water reactor (PWR), the fe asibility of an asymptotic equilibrium four-batch cycle fuelled solely with the proposed PuO2-Er2O3-ZrO2 inert matrix fuel (IMF). The present paper pr esents the results of more recent investigations related to 'real-life' sit uations, which call for transition configurations in which mixed IMF and UO 2 assembly loadings must be considered. To determine the influence of the i ntroduction of IMF assemblies on the characteristics of a UO2-fuelled core, three-dimensional full-core calculations have been performed for a present -day 1000 MWe PWR containing up to 12 optimised IMF assemblies. (C) 1999 El sevier Science B.V. All rights reserved.