Core with unenriched MOX fuel for a Microreactor PWR

Abstract

Microreactors, with their compact design, high efficiency, and robust operational characteristics, represent a promising solution for clean and reliable energy generation, particularly in remote regions or emergency scenarios. A key aspect of the development of these systems is the diversification of nuclear fuels beyond conventional uranium dioxide, aimed at enhancing fuel-cycle efficiency, reducing radioactive waste, and mitigating nuclear proliferation risks. This work presents the conceptual design of a microreactor core using MOX fuel without uranium enrichment. Several initial compositions of PuO₂ + UO₂ were evaluated, and the mixture that yielded the best performance, discussed throughout the article, was 15% PuO₂ and 85% UO₂. This composition met all design constraints and enabled a fuel cycle of approximately 15 years, operating at microreactor power levels. The SCALE computational system was employed to define the fuel cell and to perform the core burnup calculations. The results demonstrate the feasibility of using unenriched MOX in microreactors, highlighting its potential to expand fuel-cycle flexibility and contribute to a more sustainable and diversified energy supply.