二级PSA在严重事故管理中的应用研究

Study of Application of Level 2 Probabilistic Safety Analysis in Severe Accident Management

二级概率安全分析(PSA)可用来定量评估严重事故风险,是评价严重事故管理的良好工具。通过研究二级PSA应用于严重事故管理的一般方法与流程,以某二代改进型核电厂二级PSA模型为例,对严重事故管理导则中“一回路卸压”和“一回路应急注水”两个关键操作进行了定量评价。评价表明进入严重事故管理导则后立即执行“一回路卸压操作”可大幅度降低大量放射性释放风险,执行“一回路应急注水操作”对于降低进程较慢的事故序列大量放射性释放风险贡献较大。研究表明国内核电厂针对严重事故的管理还有进一步提升空间。。

Level 2 Probabilistic Safety Analysis(PSA)can be used to quantitatively assess the risk of severe accident and is a good tool to evaluate the severe accident management.By studying the general method and procedure for the application of level 2 PSA in severe accident management,taking an improved generation-Ⅱnuclear power plant as an example,the“primary loop depressurization operation”and the“primary loop emergency water injection”in severe accident management guideline are quantitatively evaluated.Analysis shows that performing the“primary loop depressurization operation”immediately after entering the severe accident management guideline can greatly reduce the risk of large radioactive release,and performing“primary loop emergency water injection operation”contributes greatly to reducing the risk of large radioactive release in the slower accident sequence.The study shows that there still has further improvement room in severe accidents management for nuclear power plants in China.