Safety evaluation of the flashing-driven natural circulation IPWR against Loss-of-Feedwater accident

Abstract IP100 reactor is a flashing-driven natural circulation IPWR in which the passive techniques are extensively utilized to acquire excellent safety performance. In this study, the safety performance of the IP100 reactor is evaluated against Loss-of-Feedwater accidents with different assumptions. The simulation model of the IP100 reactor along with its PRHRS is established by RELAP5/MOD3.4 code. Parametric analyses are conducted to reveal the effect of pressurization space volume, downcomer flow area and heat transfer area of the PRHR-HX on the reactor’s safety. The results show that the self-regulation mechanisms, including the self-pressurization mechanism and flashing-driven natural circulation, along with the PRHRS provide the IP100 an outstanding safety performance during the LOFW accident. A larger pressurization space volume and a smaller downcomer flow area offer a safer reactor performance. It is feasible to reduce the heat transfer area of the PRHR-HX for a compact configuration.