重水堆停堆工况下单相自然循环热阱有效性分析

Analysis on Effectiveness of the Single-phase Natural Circulation Heat Sink of PHWR under Shutdown Conditions

对重水堆核电厂停堆冷却剂丧失强迫循环后,单相自然循环热阱的有效性进行了计算分析。通过分析发现,每环路内一台或两台蒸汽发生器可用时,主热传输系统都可以建立稳定的自然循环,排出堆芯热量。一台蒸汽发生器可用时,两燃料通道内包壳由于冷却条件的不同有温差存在。在同一堆芯衰变功率水平下,主系统内自然循环流量受环路内可用蒸汽发生器数量影响较小。

The effectiveness of the single-phase natural circulation heat sink of PHWR under reactor shutdown and loss of coolant forced circulation conditions is analyzed. Results of cases that either one steam generator （1 SG） is available or two steam generators （2 SG） are available in each loop show that the heat transfer system could establish steady single-phase natural circulation, and remove the core decay heat. In 1 SG case, the temperature of fuel cladding in two channels are different due to different cooling conditions, and in both cases, the channel mass flow rate shows little difference under the same core decay power.