Analysis of distribution of feed water through J tubes in feed water ring of chashma nuclear power plant

In a typical pressurized water reactor's (PWR) steam generator, the primary component for distribution of feed water in secondary side is feed water ring. In this research, computational fluid dynamics analyses are carried out to determine the flow as well as pressure distribution in feed water ring with J tube. Furthermore, velocity contour at the J tube and feed water ring junction has been plotted. It was concluded that the junction is subjected to erosion-corrosion because of a higher erosion velocity through those tubes. So, by moving these tubes to other locations can increase the life of feed water ring. The flow distribution of feed water ring of Chashma nuclear power plant was also compared with other kinds of headers used. A modified design of feed water ring was suggested. The modifications resulted in a decreased erosion-corrosion risk on the surface of feed water ring. Additionally, the performance of feed water ring in main feed water line break accident was also carried out, reverse flow observed before closure of check valve was 1154 kg/sec. A pressure surge of 52 MPa was observed after the closure of check valve, which may result in water hammering and can damage the feed water ring.