针对REPEC加热实验的RELAP5程序模拟与分析

为研究压力容器外部流道的冷却能力及流动传热过程，在反应堆压力容器外部冷却(REPEC, Reactor Pressure vessel External Cooling)实验台架前期加热实验的基础上，采用RELAP5程序对实验工况进行模拟和对比。模拟结果与实验数据一致性较好。随加热热流、进出口面积的增加，系统内自然循环流量也增加；入口欠热度对自然循环流量的影响不是很明显；近饱和沸腾条件下，系统出现明显的两相不稳定流动。

Simulation and Analysis on REPEC Heating Experimental Mechanism

To study the cooling capacity, the flow and heat transfer process of flow channel between the reactor pressure vessel and the insulation, a reactor pressure vessel external cooling (REPEC) experimental mechanism was performed by using the heating method. The experiment was simulated and analyzed by using the RELAP5 code. The RELAP5 results generally correspond with the experimental cases. With the increase of heat flux, inlet area and outlet area, the water circulation mass flow rate increases. But the increase of water circulation mass flow rate is limited when the degree of sub-cooling increases. The system appears two phase flow instability clearly on the condition of nearly saturated boiling.