Root cause failure analysis of a division wall superheater tube of a coal-fired power station

Safety in nuclear power plants is one of the main problems in design. Steam generator reliability and performance are serious concerns in the operation of pressurized water reactors. Evidence shows that in the cold collector where tubes are connected to it probability of cracking exists. In this research stress distribution in the collector body at different operation condition of WWER-1000 nuclear power plant was analyzed and the collector stability has been investigated by analytical fracture mechanics and finite element method evaluations. Results show that the stresses in the collector body are in the elastic range and the stress intensity factors are lower than critical values. The analytical calculation shows the stability of semi-elliptical cracks near to expansion region of collector body during operation.