Platform Design inside the Reactor Pool for Stable Flow of the Hot Water Layer in the Research Reactor

Water quality is controlled by the pool water management system. A reactor hall is designed as a normal work area. Therefore, reactor operators, researchers and engineers can assess the reactor pool top area while the reactor is in normal operation. The radiation level of this area is an important design parameter in the point of radiation safety. In the many open-pool type research reactors, the hot water layer (HWL) at the upper part of the reactor pool is formed and maintained while the reactor is in normal operation. HWL temperature is maintained to be about 5~15 Celsius degree higher than the temperature of the primary coolant near the reactor structure assembly. One of design objects of the HWL is that the radiation level near the pool top should be maintained as low as reasonably achievable (ALARA) which is a design principle of radiation protection. Therefore, the personnel can work safely near the pool top area while the reactor is in normal operation. Research reactors such as HANARO in South Korea, JRTR in Jordan, RMB in Brazil and OPAL in Australia adopt this system. In this research, flow fields of HWL and primary coolant flow are simulated in the reactor pool. Geometry of the reactor pool, reactor structure assembly and primary coolant discharge header are taken into consideration for the calculation model.