Abstract In this paper, a M odified analytical I n- V essel melt R etention (MIVR) model is proposed to predict heat load on the VVER lower head vessel imposed by a steady state two-layer molten pool, with taking effect of the torospherical shape into consideration. The comparative calculation for the MIVR model was performed through a calculation of heat load from a quasi-steady state two-layer molten pool to the VVER-440 lower head wall. Then the MIVR model was adopted to analyze the IVR strategy for VVER-1000 reactor through a calculation of heat loads caused by four configurations of molten pools which were predicted by severe accident codes namely MELCOR v2.2, SOCRAT/B1, ASTEC v2.1 and ASTEC v2.0r3, respectively. The results clearly showed the effect of the torospherical shape of lower head on energy partition of oxidic pool with an increase of heat load from the oxidic pool to its vertical boundary. A parametric study on emissivity coefficients applied to the top of melt pool indicated that even without emissivity from the top (i.e. no radiation heat flow upwards), the peak heat flux from the vessel wall was still significantly below the maximum value of the Critical Heat Flux (CHF).

中文翻译：

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考虑对流球下水头容器影响的 VVER-1000 容器内熔体保留策略分析

摘要 在本文中，提出了一种改进的分析 I n-V essel 熔体保留 (MIVR) 模型来预测稳态两层熔池对 VVER 下水头容器施加的热负荷，同时考虑到对流层的影响。形状考虑在内。MIVR 模型的对比计算是通过计算从准稳态两层熔池到 VVER-440 下端壁的热负荷来进行的。然后采用MIVR模型，通过对严重事故规范MELCOR v2.2、SOCRAT/B1、ASTEC v2.1预测的四种熔池配置引起的热负荷计算，分析VVER-1000反应堆的IVR策略和ASTEC v2.0r3，分别。结果清楚地表明，随着从氧化池到其垂直边界的热负荷增加，下水头的对流球形状对氧化池能量分配的影响。应用到熔池顶部的辐射系数参数研究表明，即使没有来自顶部的发射率（即没有向上的辐射热流），来自容器壁的峰值热通量仍然显着低于临界热通量的最大值(瑞士法郎)。