Abstract

To simulate the complex accident phenomena of a marine reactor, the thermal-hydraulic system code RELAP5 is modified to perform the analysis under ocean conditions. An integrated reactor with a passive residual heat removal system (PRHRS) is modeled by the improved code, and the effects of different ocean motions under a total loss-of-flow accident (LOFA) and a loss-of-heat-sink (LOHS) accident are analyzed with respect to safety characteristics. The results indicate that for LOFA, the primary loop can form an effective natural circulation to cool the core, and for LOHS, the PRHRS can effectively remove the residual heat from the core to ensure the core safety. The results also show that heaving motion accelerates the drop of the first-loop temperature and enhances the heat transfer capacity of the PRHRS. Inclining motion reduces the natural circulation flow in the core. A rolling condition causes fluctuations in the mass flow rate, the variations of which are not strictly sinusoidal, and increasing the rolling period also improves the heat exchange capacity of the PRHRS.

摘要

为了模拟海洋反应堆的复杂事故现象，修改了热工水力系统代码 RELAP5 以在海洋条件下进行分析。采用改进的代码对带有被动余热排出系统 (PRHRS) 的集成反应堆进行建模，以及在完全失流事故 (LOFA) 和热汇损失 (LOHS) 下不同海洋运动的影响) 就安全特性分析事故。结果表明，对于LOFA，一回路可以形成有效的自然循环冷却堆芯，而对于LOHS，PRHRS可以有效去除堆芯余热，保证堆芯安全。结果还表明，起伏运动加速了第一回路温度的下降，提高了PRHRS的传热能力。倾斜运动减少了核心中的自然循环流动。滚动条件导致质量流量波动，其变化不是严格的正弦曲线，增加滚动周期也提高了PRHRS的热交换能力。