安全壳过滤排放系统8EUF存在的安全隐患和应对措施
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- 英文论文题名：Containment filtering systems existing safety problems and countermeasures
- 论文作者：唐琪 ; 王立峰
- 英文论文作者：TANG Qi ; WANG Li-feng ; dayabay nuclear power operations management Co.
- 年：2015
- 作者机构：大亚湾核电运营管理有限责任公司;
- 论文关键词：氢气 ; 氮气 ; 吹扫 ; 预热 ; 燃烧
- 英文论文关键词：hydrogen ; nitrogen ; purging ; preheating ; burning
- 会议召开时间：2015-09-21
- 会议录名称：中国核科学技术进展报告（第四卷）——中国核学会2015年学术年会论文集第10册（核安全分卷）
- 语种：中文
- 分类号：TL364.3
- 学会代码：EGVD
- 会议名称：中国核学会2015年学术年会
- 会议地点：中国四川绵阳
- 主办单位：中国核学会
- 学会名称：中国核学会
- 页数：5
- 文件大小：540k
- 原文格式：O
- 会议级别：全国
摘要
作为岭澳二期核电站技术改进,将岭澳一期ETY的U5子系统单独列出,新增了事故后安全壳过滤排放系统8EUF,相比岭澳一期,岭澳二期8EUF系统采用湿式过滤器替代沙堆过滤器,根据福岛反馈以及8EUF在事故工况下的使用情况,对岭澳二期8EUF涉及的相关领域进行了分析和对比,发现8EUF系统存在安全壳过滤排放管线存在氢气燃烧隐患,影响事故下8EUF的安全运行。严重事故下对安全壳内气体排放,在过滤前的混合气体含有大量氢气的情况下,在启动"U5"系统时,在安全壳隔离阀的下游由于蒸汽凝结,冷凝增加了氢气的含量,在短时期涉及氢气燃烧风险,设计上为了防止安全壳气体排放期间氢气燃烧,大亚湾/岭澳一期在安全壳隔离阀打开排放前,要投入一个预热系统,使用热空气通风,防止蒸汽遇冷凝结,同时热空气也防止沙堆过滤器沙子结板失效。U5规程中要求U5管线预热大于8H方可进行安全壳气体排放。岭澳二期8EUF通过系统备用情况下系统氮气覆盖防止安全壳排放时氢气和空气混合导致燃烧,但是安全壳隔离阀3EUF001/002VA;4EUF003/004VA之间管道正常处于关闭状态,氮气无法覆盖两者之间管道,此外,由于安全壳隔离阀所在贯穿件用压缩空气进行密封性试验,导致安全壳隔离阀之间管道充满空气,另外3EUF001/002VA和4EUF003/004VA阀门之间管道无保温层,存在着安全壳排放期间有蒸汽凝结叠加3EUF001/002VA和4EUF003/004VA阀门之间充满空气,存在着安全壳排放氢气燃烧的风险。此外8EUF系统大量管道布置在室外,且无保温层,当室外气温较低时,无法避免排放期间水蒸气凝结导致氢气体积含量增加的风险。发现该安全隐患后,目前电站采用大修期间对相关管线进行氮气吹扫的方式,实现相关管线氮气覆盖,从而避免了氢氧混合的风险。
as ling ao phase ii nuclear power plant technology improvement,the first phase of ling ao ETY U5 subsystem separately,created after the accident 8EUF containment filtering systems,compared with the ling ao phase,ling ao phase ii 8 EUF system adopts wet filter instead of sand filter,according to the fukushima feedback and 8 euf under accident conditions of usage,related to the ling ao phase ii 8 EUF field are analyzed and compared,found that eight EUF systems exist hydrogen combustion hazard containment filter drain line,affect the safe running of the accident under 8 EUF.Containment vessel emissions under the severe accident to mixed gas containing a large amount of hydrogen in front of the filter,at startup " U5" system,on the downstream side of the containment isolation valves due to steam condensation,condensation increased the content of hydrogen in the short-term,hydrogen combustion risk involved in design in order to prevent hydrogen containment gases during combustion,daya bay/ling ao phase before the containment isolation valves open emissions,to put a preheating system,using hot air ventilation,prevent steam condensation when it meets cold,hot air at the same time also to prevent the sand filter and sand plate failure.U5 rules of U5 pipeline preheat is greater than 8 h before being containment gas emissions.Ling ao phase ii 8EUF through system standby case cover to prevent the containment system nitrogen emissions when the hydrogen gas and air mixture to burn,but the containment isolation valve 3 EUF001/002 VA;4 EUF 003/004 VA pipeline between normal closed,nitrogen gas pipeline between cannot cover,in addition,due to the containment isolation valve is located throughout a leakage test using compressed air,cause the containment isolation valve between the pipeline fills the air,the other 3 EUF 001/002 VA and 4 euf003/004 VA between valve pipe without thermal insulation layer,there exists a containment vessel emissions have steam condensation during 3 stacks EUF 001/002 VA and 4 EUF 003/004 VA between valve fills the air,there is a discharge hydrogen containment of risk.In addition 8 euf system a lot of piping layout outside,and there is no thermal insulation layer,when outdoor temperature is low,cannot avoid emissions during water vapor condensation,which could lead to an increase in volume of hydrogen content in risk.
as ling ao phase ii nuclear power plant technology improvement,the first phase of ling ao ETY U5 subsystem separately,created after the accident 8EUF containment filtering systems,compared with the ling ao phase,ling ao phase ii 8 EUF system adopts wet filter instead of sand filter,according to the fukushima feedback and 8 euf under accident conditions of usage,related to the ling ao phase ii 8 EUF field are analyzed and compared,found that eight EUF systems exist hydrogen combustion hazard containment filter drain line,affect the safe running of the accident under 8 EUF.Containment vessel emissions under the severe accident to mixed gas containing a large amount of hydrogen in front of the filter,at startup " U5" system,on the downstream side of the containment isolation valves due to steam condensation,condensation increased the content of hydrogen in the short-term,hydrogen combustion risk involved in design in order to prevent hydrogen containment gases during combustion,daya bay/ling ao phase before the containment isolation valves open emissions,to put a preheating system,using hot air ventilation,prevent steam condensation when it meets cold,hot air at the same time also to prevent the sand filter and sand plate failure.U5 rules of U5 pipeline preheat is greater than 8 h before being containment gas emissions.Ling ao phase ii 8EUF through system standby case cover to prevent the containment system nitrogen emissions when the hydrogen gas and air mixture to burn,but the containment isolation valve 3 EUF001/002 VA;4 EUF 003/004 VA pipeline between normal closed,nitrogen gas pipeline between cannot cover,in addition,due to the containment isolation valve is located throughout a leakage test using compressed air,cause the containment isolation valve between the pipeline fills the air,the other 3 EUF 001/002 VA and 4 euf003/004 VA between valve pipe without thermal insulation layer,there exists a containment vessel emissions have steam condensation during 3 stacks EUF 001/002 VA and 4 EUF 003/004 VA between valve fills the air,there is a discharge hydrogen containment of risk.In addition 8 euf system a lot of piping layout outside,and there is no thermal insulation layer,when outdoor temperature is low,cannot avoid emissions during water vapor condensation,which could lead to an increase in volume of hydrogen content in risk.
引文
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