摘要
安全壳过滤排放系统(CFVS)用于严重事故情况下排出安全壳内大气以防止安全壳超压失效。其排放气体中的水蒸气在经过CFVS的管道和容器时会发生冷凝,导致氢气和氧气浓度上升,有可能引发氢气燃烧或爆炸。为了评估“华龙一号”(HPR1000)核电站CFVS内的氢气风险,建立了反应堆与安全壳模型和详细的CFVS模型,选取典型的严重事故序列对事故后CFVS开启以及混合气体进入CFVS的浓度变化过程进行了计算,并根据夏皮罗图对CFVS内的氢气风险进行判断。计算考虑了堆腔注水冷却系统(CIS)有效和失效情况下不同的安全壳大气组分进入CFVS后的浓度变化,结果显示CFVS开启时前者的氢气大部分被复合,后者的氧气则被复合反应消耗,因此2种情况下都不会发生燃烧或爆炸。计算还分析了在安全壳内布置氢气复合器以及在CFVS中实施氮气覆盖这两种缓解措施的作用,计算表明不考虑缓解措施时,CFVS内的气体组分在夏皮罗图中进入了快燃或燃爆区。研究表明HPR1000在采用了上述的缓解措施情况下,其CFVS系统内部不会发生氢气爆燃风险。
The containment filtered venting system(CFVS)is used to depressurize the containment by venting the containment atmosphere under severe accident conditions.The steam of vent atmosphere will condensate across the CFVS’s pipe and vessel,which will lead the concentration rise of H_(2) and O_(2),and the possible hydrogen combustion or explosion.In order to evaluate the hydrogen risk in the containment filtered venting system of HPR1000,the reactor and containment model and the detailed CFVS model were established.The typical severe accident sequences were selected to calculate the process of CFVS opening and the mixed gases entering CFVS with their concentrations changing after accident occurred,and the hydrogen risk in CFVS was judged according to the Shapiro diagram of the gases composition in it.It calculated the concentrations variation of different containment atmosphere composition after entering the CFVS under the cavity injection cooling system(CIS)available or failed conditions.The calculation showed that the hydrogen in the mixture gases was mostly recombined under the former condition,as well as the oxygen in the mixture gases was depleted by the recombination reaction under the latter condition at the CFVS opening time,so combustion or explosion would not occur under both conditions.The calculation also analyzed the effects of two mitigation measures,i.e.hydrogen recombiners arranged in containment and the nitrogen covering the CFVS.The results showed that without the mitigation measures,the gases composition in CFVS enter the combustion or detonation zone in Shapiro diagram.The research indicated that the risk of hydrogen detonation will not occur in the CFVS of HPR1000,which had the above two mitigation measures applied.
作者
周喆
蔡盟利
丁超
ZHOU Zhe;CAI Mengli;DING Chao(Reactor Engineering Department,China Nuclear Power Engineering Co.,Ltd,Beijing 100840,China;Nuclear and Radiation Safety Center,Ministry of Environmental Protection,Beijing 100082,China)
出处
《核科学与工程》
CAS
CSCD
北大核心
2022年第1期192-198,共7页
Nuclear Science and Engineering
