Abstract

GOTHIC and RELAP5 have been coupled to model the containment and passive containment cooling system (PCCS) for the Korean advanced containment designs. In the coupled system, GOTHIC models the containment and the outer shell (mid tube wall to outside surface) of the PCCS heat exchanger tubes and RELAP5 models the inner shell (inside surface to mid tube wall) and the coolant loop to the external heat sink. The coupling approach leverages the modeling capabilities of RELAP5 for piping load analysis and the capabilities of GOTHIC for containment and heat/mass transfer with noncondensing gases. With the coupled model, it is possible to apply the thermal-hydraulic load analysis on the PCCS supply and return piping considering the containment conditions predicted by GOTHIC during a loss-of-coolant accident (LOCA). This paper describes the coupling approach, a coupling dynamic linked library for GOTHIC, modifications to RELAP5, and verification of the coupling. Last, demonstration results from a LOCA simulation with four PCCS trains is provided and the results of the GOTHIC/RELAP5–coupled model are compared to a GOTHIC-only result, where GOTHIC was used to model both the containment and the PCCS.

摘要

GOTHIC 和 RELAP5 已结合为韩国先进的安全壳设计的安全壳和被动安全壳冷却系统 (PCCS) 建模。在耦合系统中，GOTHIC 模拟 PCCS 换热器管的安全壳和外壳（中管壁到外表面），RELAP5 模拟内壳（内表面到中管壁）和冷却剂回路到外部散热器. 耦合方法利用 RELAP5 的建模功能进行管道载荷分析，并利用 GOTHIC 的功能与非冷凝气体进行密封和传热/传质。使用耦合模型，考虑到 GOTHIC 在冷却剂损失事故 (LOCA) 期间预测的安全壳条件，可以对 PCCS 供应和返回管道应用热-水力载荷分析。本文介绍了耦合方法、GOTHIC 的耦合动态链接库、对 RELAP5 的修改以及耦合验证。最后，提供了具有四个 PCCS 列车的 LOCA 模拟的演示结果，并将 GOTHIC/RELAP5 耦合模型的结果与仅使用 GOTHIC 的结果进行比较，其中 GOTHIC 用于对安全壳和 PCCS 进行建模。