分层熔池下金属熔融物堆外蒸汽爆炸研究  

Research on Ex-vessel Steam Explosion for Metallic Corium Based on Stratified Molten Pool

作　　者：陈鹏 展德奎 张娟花 夏少雄 赵鑫海 CHEN Peng;ZHAN Dekui;ZHANG Juanhua;XIA Shaoxiong;ZHAO Xinhai(China Nuclear Power Technology Research Institute,Shenzhen of Guangdong Prov.518000,China)

机构地区：[1]中广核研究院,广东深圳518000

出　　处：《核科学与工程》2021年第5期995-1003,共9页Nuclear Science and Engineering

基　　金：“国家重点研发计划”资助(2019YFB1900702)。

摘　　要：压力容器下封头由于"热聚焦"效应在金属层位置最易发生失效,金属熔融物进入堆坑与冷却剂接触后有可能触发堆外蒸汽爆炸,威胁堆坑和安全壳的完整性。为了评估熔融物堆内滞留(IVR)策略下金属熔融物堆外蒸汽爆炸强度,本文使用MC3D软件建立侧边环向破口几何模型,研究熔融物液滴氧化、熔融物碎片氧化以及氧化热、产氢速率等参数对于蒸汽爆炸强度的影响,分析现象对应的机理,并对参数的重要度进行排序。敏感性分析结果表明,预混阶段熔融液滴氧化使得蒸汽和氢气空泡份额增加,导致爆炸阶段蒸汽爆炸强度被减弱;与熔融物液滴氧化相比,熔融物碎片由于比表面积大,外围的蒸汽更容易穿过氢气膜与碎片接触而持续发生氧化反应,碎片氧化反应产生的大量反应热使得蒸汽爆炸强度显著增强;金属熔融物在爆炸阶段,蒸汽空泡效应和氢气空泡效应对蒸汽爆炸强度影响较弱,占主导作用的影响因素为氧化热量。The lower head is most likely to fail next to metallic layer due to the focusing effect,which may trigger the ex-vessel steam explosion,threatening the integrity of pit and containment.In this paper,MC3 D is used to simulate the steam explosion of the metallic melt under the RPV side break case with In-Vessel Retention(IVR)strategy adopted.By establishing a circular fracture geometry model,the effect and mechanism of oxidation of melt droplets and fragments as well as the oxidation heat,hydrogen generation rate was studied.And the importance of the parameters was ranked.Sensitivity analysis results show that the molten droplet oxidation will reduce the explosion strength due to the increase of void with steam and hydrogen.Compared with droplet oxidation,the molten fragments have a larger specific surface area which is conducive to the peripheral steam passing through the hydrogen film to feed the oxidation.The large heat generated by the fragment oxidation makes the steam explosion strength significantly enhanced.During explosion phase,the dominant factor is the oxidation heat,in which the vapor and hydrogen void effect have a weaker impact on the steam explosion strength.

关 键 词：堆外蒸汽爆炸 金属氧化 RPV侧边破口 MC3D 

分 类 号：TL48[核科学技术—核技术及应用]