The results of computational modeling of experiments with heating of a water-filled and dewatered system are reported. The aim of the experiments was to test the computational methods used to analyze accidents in RBMK spent fuel storage, which is an example of a system with low heat fluxes. The calculations were performed using the RELAP5 code and a model specially developed for analyzing such experiments. It is shown that the RELAP5 code with the Reflood option gives acceptable results, but for lack of a description of surface evaporation in the code water level reduction in the calculations starts with a delay (after water boils) and occurs faster than in the experiment. When surface evaporation is taken into account by means of Balter’s empirical relation, the time dependence of the water level coincides with the experimental dependence. The variation of temperature at the control points of the heater is also close to the experiment. The heating of a dewatered system is described well by both models. Heat transfer by radiation from the heater to the vessel walls and into the ambient environment plays the main role.

中文翻译：

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低热通量系统的计算建模

报告了对充水和脱水系统进行加热的实验计算建模结果。实验的目的是测试用于分析 RBMK 乏燃料储存事故的计算方法，这是一个低热通量系统的例子。计算是使用 RELAP5 代码和专门为分析此类实验而开发的模型进行的。结果表明，带有 Reflood 选项的 RELAP5 代码给出了可接受的结果，但由于代码中缺乏对表面蒸发的描述，计算中的水位降低开始延迟（水沸腾后），并且比实验中发生得更快。当通过巴尔特经验关系考虑地表蒸发时，水位的时间依赖性与实验依赖性一致。加热器控制点的温度变化也与实验接近。两种模型都很好地描述了脱水系统的加热。通过从加热器到容器壁和周围环境的辐射传热起主要作用。