Study on Thermal-Hydraulic Characteristics of Horizontal Lead-Based Reactor Whole Core

Abstract Lead-based Fast Reactor (LFR) has high power density, strong inherent safety, and excellent maneuverability, which can meet the requirements of the multi-purpose nuclear power plant. In some specific scenarios, due to space constraints, the reactor core needs to be positioned horizontally, and the thermal-hydraulic characteristics will be different from those under vertical conditions. According to the special structure and operational characteristics of horizontal LFR, the subchannel analysis code SACOS-HLFR was developed in this paper. With the subchannel code, the thermal-hydraulic evaluation of the whole core in horizontal LFR was conducted, mainly focusing on the flow and temperature distribution of the hottest assembly. In the whole core analysis, the outlet coolant temperature of the hottest assembly increases first and then decreases along the gravity direction. In contrast to the single assembly analysis, the flow and temperature difference between the upper and lower of the hottest assembly is significantly reduced due to the crossflow mixing with adjacent assemblies. At the same time, the position of the hottest channel is moved from the upper region of the assembly to the lower region. For the hottest rod, the maximum temperature of the cladding and pellet does not exceed the corresponding limit value, the reactor code can operate safely.