Performance Evaluation of Fission Transmutation Layers in ARC Reactor-Based Fusion-Fission Systems

Abstract

The development of high-temperature superconductors allows the design of smaller fusion reactors based on tokamak-type magnetic confinement with very high magnetic fields, as presented by MIT, the affordable robust compact reactor (ARC). This research explores how these advancements could influence the design of a hybrid fusion-fission reactor (HFFR), proposing and evaluating a hybrid model based on the simplified ARC. The first part of the study focuses on the transmutation layer design determined by the optimal radial position beyond the beryllium blanket. The second part evaluates the transmutation layer insertion as a fusion-fission system using five different configurations variating the from in the number of layers used, from one homogenized transmutation layer (HF) to twelve heterogeneous transmutation layers (H12). The primary distinction between the models lies in the number of layers within the fission transmutation layer. Thus, the models were analyzed based on several parameters such as the ratio of coolant to fuel volume, multiplication factor, and the evolution of the burnup fuel. The results indicate that a coolant-to-fuel volume ratio of 2.2 significantly enhances performance. Additionally, increasing the number of fuel layers in the fission system affects both the capture and fission rates across the layers and throughout the burnup process. Notably, models H4 and H6 demonstrate superior performance, taking advantage of the hardened energy spectrum from the fusion to facilitate the transmutation of transuranic elements through fission.