Experimental Research on Bypass Flow Characteristic between Core Barrel and Core Shroud of CAP1400 Reactor

An experiment concerned with bypass flow between core barrel and core shroud was carried out. Not only resistance characteristics of bypass flow but also bypass mass flow rate proportion corresponding to original pressure drop of core under different orifice diameters of core shroud support plate were investigated. It is found that when orifice diameter is 1.2 times larger than the minimum orifice in experiment, bypass mass flow rate exceeds 0.5% of total core mass flow rate under reference core pressure drop condition. Otherwise the bypass mass flow rate is less than 0.5% of total core mass flow rate under other orifice diameters conditions.