Research on the rapid evaluation method for the corrosion defects in seawater cooling pipes of nuclear power plants

The corrosion of the fluid to the pipes could damage the pipes, and then affect the safe operation of the whole pipeline system in the nuclear power plant. To evaluate the influence of the corrosion defects on pipe integrity, it is necessary to carry out the stress analysis and then calculate the remaining strength of the pipes with defects. In this paper, the remaining strength of the pipes with defects has been calculated, the minimum required wall thickness of the pipes has been obtained, and the defects have been evaluated according to SY/T 6477 Standard. Stress distribution of the pipes has been obtained under pressure and nozzle loading with the finite element method. Based on the RCC-M Standard, the strength evaluation has been conducted. It is found that the stress calculated from SY/T 6477 Standard is close to that from the finite element method, which can be considered that the evaluation method summarized from SY/T6477Standard is suitable for the current pipes containing defects under nozzle loadings. Therefore, this method can be used to evaluate the corrosion defects of the seawater cooling pipes rapidly, and provide advice for the monitoring and repair of the pipes containing defects in nuclear power plants.