Numerical Analysis Study to Identify the Leak Cause of a Feedwater Heater Vent Pipe in a CANDU plant

Abstract

Piping installed in nuclear power plants is affected by various degradation mechanisms and may be ruptured after being gradually thinned. The degradation mechanisms such as flow-accelerated corrosion (FAC), cavitation, liquid droplet impingement erosion (LDIE), etc., can lead to costly outages and repairs, resulting in plant reliability. In August 2008, the header pipe in the high pressure feedwater heater vent system was leaked at a Korean CANDU nuclear power plant. As the result of inspection after cutting the pipe, it was identified that the leak was evoked due to LDIE. This paper presents the numerical analysis result using ANSYS FLUENT for the purpose of identifying the cause of the leak,the comparison results of the wear rate based on the both the existing evaluation models and the measured thickness data.