Experimental and computational investigation of a natural circulation system in Regional Energy Reactor-10 MWth

A small- and medium-sized nuclear reactor (SMR) has drawn attention because it is used for multi-purpose applications and the SMR has the virtue of being safer than a large-sized nuclear reactor. According to this tendency, the Regional Energy Research Institute for Next Generation (RERI) has been designing a Regional Energy Reactor-10 MWth (REX-10). REX-10 is an integral type pressurized water reactor (PWR), and is designed to remove heat by natural circulation to improve safety. To investigate the natural circulation characteristics of REX-10, we designed a REX-10 Test Facility (RTF) using the scaling law and carried out experiments in two parameters: heater power and primary pressure. The experimental results have shown that the heater power is the most important parameter of the natural circulation behavior. On the other hand, the primary pressure does not show remarkable effect on natural circulation. In addition, MARS code simulation has been conducted to compare the experimental results and its results show good agreement with the experimental data. Finally, evaluation of the capability of natural circulation was conducted. The result of the evaluation shows that the RTF is sufficiently capable of removing the thermal power of this system.