船用核动力装置部件失效分析与安全评定

Failure Analysis and Safety Assessment of Main Bolt Used in Nuclear Power Device for Ship

主螺栓是船用核动力装置的重要部件,通过微观形貌观察和腐蚀产物分析,研究了断裂与未断裂主螺栓的失效原因,结果表明:失效主要是由应力腐蚀引起的;应用断裂力学方法对主螺栓进行了安全评定,计算出其临界裂纹尺寸为4.2 mm,可作为主螺栓安全评定的依据,且具有足够的安全余量。

The causes leading to the failure of the main bolt——an important component of primary coolant circuit in the nuclear power plant of ships,were investigated based on the analyses of the micro-morphologies and corroded products of the fractured and non-fractured main bolts.The safety of the main bolt was assessed based on fracture mechanics,and the critical crack size was calculated as well.It was found that the failure of the main bolt was attributed to cracking induced by stress corrosion.The computed critical crack size could be used as a criterion for the safety assessment of the main bolt,with the possibility to over-estimate the safety of the main bolt to be neglectable.