CFD simulation on sub-channel blockage in the fuel plate of RSG-GAS reactor

The main objective of the paper is to simulate flow blockage in the sub-channel fuel plate in the Indonesian RSG-GAS research reactor. Utilizing SolidWorks CFD Flow Simulation, this simulation investigates coolant and fuel plate temperatures in scenarios involving blockage areas from 60% to 90%. In the first scenario, the blockage is positioned at the inlet sub-channel, while the second scenario involves the position of the axial power peak. The power peaking distribution of the fuel is based on the neutronic calculations. Utilizing the COOLOD-N2 Code, a one-dimensional steady calculation performed for comparison with the SolidWorks. Under unblocked conditions, the comparison indicates there are no significant differences in the coolant and fuel plate temperatures. The results of flow blockage indicate that in the case of the second scenario with a 90% blockage, the maximum plate surface temperature reached 94.9 °C, while in the first scenario, it was 86.5 °C, both still below the Onset Nucleate Boiling Temperature of 125.5 °C. From a safety perspective, the CFD simulation for the RSG-GAS blockage channel reveals the absence of boiling. This simulation complements an accident analysis conducted in the RSG-GAS reactor, further enhancing safety considerations.