Abstract The concept of in-vessel retention (IVR) by passive external reactor vessel cooling (ERVC) in a flooded cavity during a severe accident has now been recognized as a viable approach to retain the radioactive core melt (i.e., corium) within the reactor vessel. During the process of long-term in-vessel cooling of core melt, the heat flux must remain below the critical heat flux (CHF) level to maintain a regime of nucleate boiling such that the integrity of the reactor pressure vessel (RPV) is not compromised. In this study, steady-state data for downward facing boiling (DFB) obtained under simulated IVR-ERVC conditions in the Subscale Boundary Layer Boiling (SBLB) test facility is critically analyzed based upon which a new DFB correlation is derived mathematically from theoretical considerations with the coefficients resulting from the scaling analysis being determined from the DFB data. The new correlation which adequately predicts the local variation of the nucleate boiling heat flux along the outer surface of the RPV under IVR-ERVC conditions can be used to describe the long-term cooling behavior of the corium within the RPV of advanced nuclear power plants.

中文翻译：

---

开发用于热力水力分析的面向下的核沸腾相关性

摘要 在严重事故期间，通过被动外部反应堆容器冷却 (ERVC) 在淹没腔中进行的容器内滞留 (IVR) 概念现已被认为是将放射性堆芯熔体（即，真皮）滞留在反应堆内的可行方法。血管。在堆芯熔体的长期容器内冷却过程中，热通量必须保持在临界热通量 (CHF) 水平以下，以维持核沸腾状态，从而使反应堆压力容器 (RPV) 的完整性不受影响。妥协了。在这项研究中，在亚尺度边界层沸腾 (SBLB) 测试设施中，在模拟 IVR-ERVC 条件下获得的向下沸腾 (DFB) 稳态数据进行了批判性分析，基于此，新的 DFB 相关性从理论考虑中以数学方式推导出来，系数为根据 DFB 数据确定缩放分析。新的相关性充分预测了在 IVR-ERVC 条件下沿 RPV 外表面的核沸腾热通量的局部变化，可用于描述先进核电站 RPV 内真皮的长期冷却行为。