SUMMARY

As interest in the implementation of advanced reactor technology grows, neutronics tools developed with water reactor applications in mind must also be verified for suitability to advanced reactor features. Multiple parties are pursuing a variety of Molten Salt Reactor (MSR) designs, but only the Molten Salt Reactor Experiment (MSRE) performed by Oak Ridge National Laboratory (ORNL) has been demonstrated and provided well-documented experimental data. This data will be utilized to validate the Coarse Mesh Radiation Transport (COMET) method with results from the two zero-power criticality experiments performed in the MSRE. The COMET method is a hybrid stochastic-deterministic method for solving the transport equation, and it provides high-fidelity results while achieving significant gains in computational efficiency (several orders of magnitude) over purely stochastic as well as deterministic transport methods for whole-core solutions. The first component of this work consists of forming the zero-power U-233 experiment benchmark for submission to the International Handbook of Evaluated Reactor Physics Benchmark Experiments (IRPhE). This submission aims to address the scarcity of available experimental MSR data for benchmarking reactor physics and neutronics codes, as the zero-power U-235 criticality experiment for the MSRE is currently the only evaluated MSR benchmark problem in the IRPhE. The second component will be utilizing both the U-233 and U-235 MSRE benchmark problems for the experimental validation of the COMET method/code in this application. The COMET method has been numerically validated against direct continuous energy Monte Carlo methods in a variety of Light Water Reactor (LWR) and advanced reactor designs, but it has not yet been experimentally nor numerically validated against a salt-fueled MSR problem.