关于正确理解堆芯损坏概率的进一步讨论

Further Discussion on Appropriate Interpretation of Core Damage Probability

堆芯损坏概率/频率这一指标经常用在关于核电安全性的讨论中,其数值意义及概念的认识或理解尚需进一步明确。本文利用概率论相关方法,在深入了解堆芯损坏频率(CDF)获得过程的基础上,讨论了利用泊松过程来计算堆芯损坏概率(CDP)的方法。并说明了直接叠加单个堆年CDF来估计CDP,是一种常见的近似方法,其误差会随着堆年数的增多而变大,应明确其适用范围。计算表明:在10%误差的条件下,对CDF为1×10-4/(堆.年)的堆,用近似方法可讨论到约2 000堆.年,而对CDF为1×10-5/(堆.年)的堆,则可讨论到约20 000堆.年。同时在使用该指标时,不能忽略反应堆发生堆芯损坏这一事件本身的随机属性。

Core damage frequency/probability （CDF/CDP） is an important indicator to discuss, describe or compare the safety of nuclear power plants （NPPs）. However, the concept of CDF/CDP may require to be clear to people. Generally, for the total CDP estimation purpose of multiple reactors, the damage probability of each reactor can not be accelerated directly when the reactor-year is increasing. The paper discussed the Poisson process applied in the CDP calculation. And the relationship between the CDF and CDP, and the stochastic characteristic of the core damage （CD） event should be considered intensively and cautiously in order to achieve the precise result. Results show that the simple estimation method can be valid about 2 000 reactor-years for the reactors which CDF is 1×10^-4/reactor-year, when 20 000 reactor-years for the reactors which CDF is 1×10^-5/reactor-year. Moreover, the stochastic property of CDP must be kept all along during the discussion.