核级阀门故障概率的时变性研究

Research on Time-Varying Characteristics for Nuclear Power Valve Failure Probability

核级阀门具有高可靠性、长寿命的特点,阀门历史失效数据的小子样问题突出,并且由冲击、振动、磨损、腐蚀等耗损性因素引起的故障,其故障概率具有时变性,随时间的增加而增大。故障概率p为常数的Jeffreys先验模型不能以合理概率复现观察数据,故满足不了分析p的时变性要求。对服从Binomial分布的阀门故障数据建立广义线性模型,研究概率p的时间趋势;在评价模型复现观察数据能力时不仅进行定性图检验,而且还利用贝叶斯?2统计量进行定量化检验;经过定性和定量的双重检验,表明该模型具有良好的预计能力,可以分析阀门故障概率p的时变性。

Nuclear power valve has the characteristics of high reliability and long lifetime, and its failure data have obvious small sample problem. The nuclear power valve failure are caused by loss factors of impact, shaking, abrading and corrosion. The failure probability has time trend, and the p will raise （decrease） with the increasing of time. The Jeffreys prior model of invariable p can not reflect the time trend of p very well, so it can not analyze the time-varying characteristics of p. This paper built the Generalized Linear Model （GLM） for valves failure data having Binomial distribution, analyzed the time trend of p inspected the model through posterior predictive distribution, and assessed the model ability of replicating observed data by graph inspection and Bayesian chi-square. The results showed that GLM had well fit index and was more propitious to assess the failure probability p of valve.