A numerical analysis for a damage propagation in a plate-type fuel assembly of a research reactor

Abstract

If several flow channels are completely blocked in a plate-type fuel assembly of research reactors with high power density, a flow instability (FI) can occur in an unblocked channel and can be propagated to the other adjacent flow channels. Such FI propagation can cause a propagation of fuel plate damages during the flow blockage accident. Hence, the thermal hydraulic behaviors of flow channels have been analyzed in order to investigate the FI propagation process by the simulation of CFD code for a multiple flow channel blockage in KiJang Research Reactor (KJRR) which is the model reactor assumed for this paper. Simulation results show that a FI occurs at the first unblocked channel if 8 flow channels are completely blocked and most of fuel plates are significantly damaged in 29 s after a complete blockage of 8 flow channels occurs in a plate type fuel assembly of the model reactor.