Fuel Performance Modeling for Proposed Th-Based Canadian SCWR

Abstract

The fuel assembly for the Canadian Super Critical Water Reactor (SCWR) is in the conceptual design phase. The proposed fuel pellets are made of ceramic Th-Pu mixed oxide ((Th,Pu)O₂). Neutronics and thermal hydraulics calculations are being undertaken by the nuclear industry to optimize the fuel assembly within a pressure tube. The SCWR working groups have established two conceptual fuel element designs, which defines outer diameter, fuel composition, cladding material, exit burnup etc. A detailed fuel element performance assessment under in-reactor conditions could be used to determine cladding material thickness and suitability and to optimize the fuel pellet geometry.

This work reports the development of a fuel performance model to predict the behaviour of the Canadian SCWR fuel using the finite element method (COMSOL). An initial approach is to develop a thorium-uranium mixed-oxide ((Th,U)O₂) model. Preliminary results from this model agree with fuel irradiation data. Uranium dioxide (UO₂) fuel, under the same conditions, is also being modeled and compared. A plan to model (Th,Pu)O₂ SCWR fuel will also be briefly presented here.