Optimization of the Fuel Assembly for the Canadian Supercritical Water-cooled Reactor (SCWR)

Abstract

The design of the Canadian Supercritical Water-cooled Reactor (SCWR) has recently progressed to its conceptual stage. Dedicated efforts in thermalhydraulics, fuel design and reactor physics are committed within the industry to refining the initial designs of this advanced reactor for its optimal performance in factors such as the burnup, the channel void reactivity (CVR), the critical heat flux (CHF), the linear element rating (LER) and others. This work considers the systematic application of numerical techniques for solving such an optimization problem. The fuel assembly design is first structured into an optimization problem, and the feasibility of applying a generic optimization technique to solving optimization problem for both SCWR 78- and 64-element bundles is investigated. Both of these concept fuel assemblies are designed to utilize a thorium based fuel with a plutonium driver. Lattice codes such as WIMS-AECL and SERPENT are used to solve neutron transport equations for the infinite lattice. The decision variables of the optimization problem are the fresh fuel content and bundle geometry (including fuel rod radii, rod annuli radii, among others). The decision variables are used to calculate an objective function, or index of performance, that include components such as the fuel discharge burnup, the surface heat flux (SHF), and the radial form factor (RFF). These components that form the index of performance are ultimately optimized (typically minimized) using a steepest descent method known as the Gauss method. The mathematical methodology as well as model validation will be presented along with a discussion of the details of this project and future work. In addition, some preliminary results on fuel optimization will be presented.