摘要
压水堆核电站中的一回路主冷却剂管道用铸造奥氏体不锈钢(CASS)长期在反应堆环境下服役,面临热老化脆化问题。本文利用时效参数外延法,对其主要用钢Z3CN20-09M钢在长期运行后的热老化脆化程度进行评估,并对材料的使用寿命进行预测。评估结果表明:在时效参数P=3.48的时效状态下,Z3CN20-09M钢中的铁素体发生了调幅分解,产生了热老化脆化倾向;同时,拟合得出该材料在288~327℃服役后的总冲击能量随时效参数P的变化关系,预测冷热腿管道用Z3CN20-09M钢在接近延寿期60满功率运行年限服役是安全的。
Cast austenitic stainless steel(CASS) used in main coolant pipes of the primary loop in pressurized-water reactor(PWR) nuclear power plants faces the problem of thermal aging embrittlement after long-time operation in the reactor environment. In this study, the aging parameter extrapolation method is used to evaluate the degree of thermal aging embrittlement and predict the service life of the mainly used Z3CN20-09 M steel after long-time operation. The evaluation results indicate that, when the aging parameter P is 3.48, the spinodal decomposition takes place on the ferrite of Z3CN20-09 M steels, which results in a thermal aging embrittlement tendency. In the meantime, the relationship between the total impact energy and aging parameter P of the Z3CN20-09 M steel after service at 288 ℃ to 327 ℃ is obtained by fitting. It is predicted that the Z3CN20-09 M steels used for the cold and hot leg pipe is safe when its extending service life is close to 60 effective full power years.
引文
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