Prediction of Missouri S&T Reactor's Natural Convection with Porous Media Approximation


The Missouri University of Science and Technology (Missouri S&T) is considering a power uprate of its 200 kW research reactor (MSTR). To support this goal, preliminary CFD analysis was carried out to complement neutronics analysis on the current reactor. A three-dimensional parallel-plate model was developed using STAR-CCM+ v 8.04, and steady-state simulations for fluid flow under natural convection were performed. Cosine-shaped heat flux as a function of reactor power was applied on fuel plates. Temperature field in the hot channel were calculated at 200 kW, 100 kW, 60 kW and 20 kW power levels, and the resulting temperature profiles described the heat flow from the fuel plates into the surrounding water coolant/moderator. To model the entire reactor, porous media approximation at the core was applied to reduce the computation cost. Using CFD simulation for four power levels, the inertial resistance tensor and viscous resistance tensor were found to be 281,005 kg/m4 and 7121.6 kg/m3 respectively. Subsequently, the parallel-plate section was replaced with a porous section. The pressure drop within the channel for both cases was found to be within 10% of each other. For the investigation of the heat flow in the MSTR pool, a porous region core was defined by both resistance tensors and porosity of 0.7027. A section of MSTR with 3 fuel elements and a power density of 1.86E+6 W m-3 was modeled with one third of the reactor pool. Temperature measurements were made to validate the simulation results at 200 kW. The average temperature difference between the measured values and the simulated results was 0.29 K. The maximum difference between the simulation results and the measurements was observed to be less than 2 K at 0.9 m from the bottom of the core which is also 0.3 m above the top of the fuel. After porous media model validation, flow field in the reactor pool were generated with the new active cooling system operated at 35% pumping capacity. These results will provide a framework for power uprate safety analysis.


Nuclear Engineering and Radiation Science

Keywords and Phrases

Flow of fluids; Fuels; Heat flux; Heat resistance; Heat transfer; Lakes; Natural convection; Porous materials; Temperature measurement; Tensors; Water cooling systems; Computation costs; Pumping capacity; Science and Technology; Simulated results; Steady-state simulations; Temperature differences; Temperature profiles; Viscous resistance; Computational fluid dynamics

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Article - Journal

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© 2015 Elsevier, All rights reserved.

Publication Date

01 Apr 2015