Bridging Microreactor Design and Economics: The Microreactor Optimization Using Simulation and Economics (MOUSE) Tool

Microreactor Optimization Using Simulation and Economics (MOUSE) is an integrated framework that links nuclear microreactor design analysis with reactor economic assessment. The tool performs core design calculations using the OpenMC Monte Carlo particle transport code and incorporates simplified balance-of-plant modeling. From an economic perspective, MOUSE generates detailed bottom-up cost estimates, including total capital cost and levelized cost of energy (LCOE) for both first-of-a-kind and nth-of-a-kind microreactor deployments. The underlying cost correlations are derived from MARVEL project data and supplemented with information from the open literature.

By unifying reactor physics simulations with economic modeling, MOUSE allows users to assess the effects of a wide range of technical factors—such as advanced moderators, design and geometry variations, and material or fuel selections—as well as economic assumptions including interest rates and construction timelines. This holistic approach helps identify design and technology pathways that improve microreactor economic viability. Furthermore, leveraging the WATTS toolkit, MOUSE enables optimization studies, parametric evaluations, and uncertainty quantification and propagation.