Verification of OpenMC Neutronic code for Transuranic Waste Incineration in Reduced Moderation Boiling Water Reactor

Transuranic waste incineration in nuclear reactors that are moderated and cooled by light water is possible by reducing the effect of neutron moderation in the core. This type of reactor is being developed by Hitachi under the name of resource-renewable boiling water reactor (RBWR). RBWR is a next generation boiling water reactor (BWR) that features the capability of multi-recycling and TRU incineration. This type of reactor retains key benefits of the commercially available advanced boiling water reactor (ABWR) in terms of extensive operating experience and proven record of high reliability. This work presents a neutronic analysis at fuel assembly level of RBWR-TB2 which is a TRUs-burning configuration of RBWR using an open-source Monte Carlo particle transport code OpenMC. The primary objective of this work is to demonstrate the capability of the open-source tool to analyze complex nuclear reactor geometry to ensure the feasibility of incinerating transuranic waste in RBWRTB2. Important neutronic parameters such as multiplication factor, axial power distribution, fuel burnup, fission products at the fuel assembly level are computed and compared with the existing results from another Monte Carlo program SERPENT2. The results achieved by comparing SERPENT2 and OpenMC show a good agreement. The maximum deviation for keff was 54 pcm while the code-to-cdoe deviation on average was 24 pcm. The maximum deviation for APFmax was 1958 pcm and the maximum deviation for RPFmax maximum was -162 pcm. For actinide inventory Am-242, Pu-241, and U-236. Am-242 had the largest relative difference of 7.92 percent. Thus, this work has demonstrated that the OpenMC permits getting results that are comparable to a proprietary Monte Carlo neutronic code, SERPENT2. As a result, OpenMC can be utilized for other types of calculation related to RBWR-TB2 in the future.