压水堆严重事故过程中堆内氢气源项分析

采用一体化严重事故分析程序ASTEC,分别对丧失给水事故(LOFA)和全场断电事故(SBO)进行了模拟。结合丧失给水事故阐述了Zr、Fe、B4C与水氧化反应的机理,比较了Zr、Fe、B4C氧化反应释放的氢气的质量、速率和氧化反应开始的时间。结果表明,事故早期氢气主要来自Zr的氧化反应,Fe氧化反应产生的氢气约占氢气总产量的10%。另外,还比较了LOFA和SBO事故过程中氢气的释放。结果表明,同一反应堆在不同的严重事故进程中产生的氢气的质量、速率、氧化开始的时刻以及堆内氢气分布可能有很大的差别。因此,在进行事故早期氢气源项风险评价的时候要根据不同的事故进程,具体问题具体分析。

The Analysis of PWR In-vessel Hydrogen Source Term during Severe Accidents

The LOFA and SBO severe accidents are simulated with the ASTCE code separately.The reaction mechanism between metals(Zr,Fe,B4C) and steam is described in LOFA.The mass,rate and starting time of hydrogen production are compared.The results show that the hydrogen mainly came from the Zr oxidation,and the hydrogen from Fe oxidation is only 10% of the total hydrogen.The hydrogen production during LOFA and SBO accidents are also compared.The mass,maximum rate and starting time of hydrogen generation of the same reactor are quite different in different severe accident sequence.So it is necessary to analyze the hydrogen source term during severe accident and take some effective measures.