Screening and Management of Dead-End Pipe in Qinshan NPP

This paper introduces the occurring conditions for dead-end pipe phenomenon and the corrosion failure mechanism in the pressurized water reactor nuclear power plant. According to the screening process for the dead-end pipes, the dead-end pipes in the Qinshan nuclear power plant of 300 MW Unit is screened to determine the dead-end pipes concerned. Management countermeasures are proposed. The results show that the dead-end pipe phenomenon is caused by the water saturation vaporization in the dead-end pipe, and the reason is that the water in the dead-end pipe is heated and the pressure can not be maintained higher than the saturation pressure. The dead-end pipe phenomenon can be control and alleviate by improving the relevant procedures, and can be eliminated completely by system modification.