b'Coupled MultiphysicsMultiphysics coupling between structural dynamics, neutronics, and thermal Safety Analysis of Moltenfluids transport reduces development time and cost of new molten salt reactors. Salt Reactors SubjectedT his research developed a proof-of-concept demonstration of a high fidelity coupled multiphysics simulation of a molten salt reactor shaking during to Earthquakes an earthquake. The demonstration leveraged MOOSE and used three MOOSE-based applications: (1) Mastodon, to simulate structural dynamics and mechanics from seismic shaking and acoustic wave propagation in the molten salt, (2) Pronghorn, for reactor thermal hydraulics, and (3) Griffin, for neutronic feedback. Molten salt reactors are being pursued by a range of reactor developers but have little precedence apart from an experimental facility built in the 1950s. Their safety PROJECT NUMBER:and licensing cases can be significantly strengthened by a thorough evaluation 21A1057-029 of their behavior during earthquake-based transients, ultimately aiding their deployment. Furthermore, significant cost savings can be envisaged from reducing TOTAL APPROVED AMOUNT:conservatism because earthquake-based considerations are key cost drivers. $143,000 over 2 yearsThe project started with independent, uncoupled molten salt reactor simulations using PRINCIPAL INVESTIGATOR:Mastodon for seismic analysis and Griffin plus Pronghorn for neutronics and thermal Guillaume Giudicelli hydraulics. The research then progressed by gradually increasing the level of coupling CO-INVESTIGATORS: by transitioning from loose coupling to a tightly coupled simulation using the MOOSE Abdalla Abou-Jaoude, INL MultiApp system where the seismic accelerations in the molten salt are transferred Chandu Bolisetti, INL from Mastodon to Pronghorn plus Griffin, which in turn, provided the temperature and Kyung Tae Kim, INL density fields to Mastodon at each timestep. This first-of-a-kind coupled multiphysics Mauricio Tano, INL simulation analyzed a wide range of complex seismic transients and demonstrated a Paolo Balestra, INL large impact of lower frequency vibration on the power production of the core in an uncontrolled transient. It provided deep novel insights into the level of coupling needed between the seismic analysis and reactor dynamics to accurately simulate earthquake transients. Unrelaxed fixed-point iteration between each physics satisfactorily converged, allowing for an optimization of the coupling scheme based only on the time stepping requirements of each physics. PRESENTATIONS:Bolisetti, C., K. T. Kim, G. L. Giudicelli, P. Balestra, S. L. N. Dhulipala,A. Abou-Jaoude, Coupled Multiphysics Simulations of Molten Salt Reactors Subjected to Earthquakes, 2021 American Nuclear Society meeting, Washington DC, USA, Nov. 30Dec. 3.Bolisetti, C., G. L. Giudicelli, P. Balestra, S. L. N. Dhulipala, M. E. Tano,A. Abou-Jaoude, Multiphysics Coupled Seismic Safety Analysis of Molten Salt Reactors, 2022 American Nuclear Society meeting, Phoenix, AZ, USA, Nov. 1317.41'