In the course of severe accident in a nuclear power plant, the corium mixture may flow down in the reactor pit and start a thermal attack of the basemat concrete. A simple way to terminate the melt progression may be to add water on top of it. Among the various physical processes that may participate in the quenching, water may penetrate into the solidified corium through cracks generated by the thermal stress during the solidification.

The present paper aims at providing a clarification of the process though an analysis of the few dedicated experimental data available using proto-typical corium, namely the SSWICS 1-7 experiments. At first, a general reminder and analysis of the data is given. Then, the thermal-hydraulic aspects are investigated through the construction of a dedicated heat flux correlation and its use via the experimentally measured post-test permeabilities. The analysis is supported by 1D and 2D evaluations with the multiphase flow code MC3D-PREMIX, slightly modified for the purpose. It is concluded that the heat flux drastically decreases with the amount of added concrete material. Furthermore, 2D border effects are investigated and their importance highlighted in view of the experimental results analysed. These effects should explain the absence of observation of water ingression heat flux in the cases with large concrete amounts. Following, the paper proposes a model for the created permeability. Due to the complexity of the process and to the large uncertainties of the needed material properties in the considered situation with very high temperatures, a semi-empirical model is derived.

Lastly, the model is adapted to the situation with internal decay heat, although no open experimental data is available to precisely support any model. A complete modeling is out of the scope of the paper, hence the focus is to provide hints for a first analysis of the impact of decay heat on its coolability.

在核电站发生严重事故的过程中，钐混合物可能会在反应堆坑中向下流动并开始对底垫混凝土进行热侵蚀。终止熔化进程的一种简单方法可能是在其顶部加水。在可能参与淬火的各种物理过程中，水可能通过凝固过程中热应力产生的裂纹渗入凝固的真皮中。

本论文旨在通过对使用原型真皮可用的少数专用实验数据（即 SSWICS 1-7 实验）的分析来澄清该过程。首先对数据进行一般性的提醒和分析。然后，通过构建专用的热通量相​​关性及其通过实验测量的测试后渗透率的使用来研究热工水力方面。该分析得到了多相流代码 MC3D-PREMIX 的一维和二维评估的支持，为此目的稍作修改。结论是热通量随着混凝土材料的添加量急剧下降。此外，研究了二维边界效应，并根据所分析的实验结果强调了它们的重要性。这些影响应该可以解释在大量混凝土的情况下没有观察到进水热通量的原因。接下来，本文提出了一个创建渗透率的模型。由于该过程的复杂性以及在所考虑的温度非常高的情况下所需材料特性的很大不确定性，因此推导出半经验模型。

最后，该模型适用于内部衰变热的情况，尽管没有开放的实验数据可用于精确支持任何模型。完整的建模超出了本文的范围，因此重点是为第一次分析衰变热对其冷却性的影响提供提示。