Mixed-oxide fuel strategies in an integral pressurized water reactor

Abstract

The integral pressurized water reactor (iPWR) will play an important role in nuclear energy development considering its outstanding safety features. To achieve high proliferation resistance, extended fuel cycles have been proposed. Other important issues to achieve nuclear energy long-term sustainability are the proper use of its fuel sources and the improvement of nuclear waste management. Therefore, fuels based on oxides mixture have been successfully used in several countries. Also, Thorium-based fuel incorporation is a current challenge for the new advanced reactor designs. This paper compared different fuel compositions using recycled Plutonium and Uranium in a conceptual reactor of the type iPWR. The use of Thorium as fertile material is presented as well. The presented study considers a standard fuel cycle with slightly enriched Uranium (below 5%) as reference. One-third of the conceptual iPWR’s core is loaded with MOX fuel assemblies and the other two-thirds with conventional UO2. These proposed fuel cycles are compared with the standard full-UO2 cycle, regarding the behavior of main safety parameters, fuel depletion, and waste production. The studied fuel compositions reached a fuel cycle length of 4 years, approximately. The results for the core parameters show that using MOX and Thorium-based fuels in iPWR fulfills the safety constraints.