Passive containment cooling systems (PCCSs) have been actively studied to improve the inherent safety of nuclear power plants. Hered, we present two concepts, open-loop PCCS (OL-PCCS) and closed-loop PCCS (CL-PCCS), applicable to the PWR with a concrete-type containment. We analyzed the heat-removal performance and flow instability of these PCCS concepts using the GOTHIC code. In both cases, PCCS performance improved when a passive containment cooling heat exchanger (PCCX) was installed in the lower part of the containment building. The OL-PCCS was found to be superior in terms of heat-removal performance. However, in terms of flow instability, the OL-PCCS was more vulnerable than the CL-PCCS. In particular, the possibility of flow instability was higher when the PCCX was installed in the upper part of the containment. Therefore, the installation location of the OL-PCCS should be restricted to minimize flow instability. Conversely, a CL-PCCS can be installed without any positional restriction by adjusting the initial system pressure within the loop, which eliminates flow instability. These results could be used as base data for the thermo-hydraulic evaluation of PCCS in PWR with a large dry concrete-type containment.

被动安全壳冷却系统 (PCCS) 已被积极研究以提高核电厂的固有安全性。在此，我们提出两个概念，开环 PCCS (OL-PCCS) 和闭环 PCCS (CL-PCCS)，适用于具有混凝土型安全壳的压水堆。我们使用 GOTHIC 代码分析了这些 PCCS 概念的散热性能和流动不稳定性。在这两种情况下，当被动安全壳冷却热交换器 (PCCX) 安装在安全壳建筑物的下部时，PCCS 的性能都会得到改善。发现 OL-PCCS 在除热性能方面更胜一筹。然而，在流动不稳定性方面，OL-PCCS 比 CL-PCCS 更脆弱。特别是当 PCCX 安装在安全壳的上部时，流动不稳定的可能性更高。所以，应限制 OL-PCCS 的安装位置，以尽量减少流动不稳定性。相反，通过调节回路内的初始系统压​​力，可以安装 CL-PCCS，而不受任何位置限制，从而消除了流动不稳定性。这些结果可用作具有大型干混凝土型安全壳的 PWR 中 PCCS 热工水力评估的基础数据。