The calculating analysis of fluid transients caused by LOCA event in primary loop

The coolant must run off wherever ruptures occur in PWR. It is called LOCA event which is the one of the most serious accidents. This paper deals with the rupture of pipe in primary loop in PWR. The ruptures involve the double-end of break, which results in that coolant jets simultaneously from the double end of break pipes, and the break opening of pipe which is a hole on the wall of pipe. The main loop links up with many large diameter pipes, while auxiliary systems linking up with main loop have thin piping system. A pipe of auxiliary system has rupture, there is still time to do something with emergency. When a main pipe breaks core may be uncovered because of a great deal of loss of coolant, the temperature of core rises so that the core may fuse. How about the flow of coolant ? Analysis is shown in this paper from a viewpoint of fluid mechanics. The research of fluid transients in LOCA event help us to know the flow condition of coolant and acquaint with the fluid force acting on pressure vessel, steam generator, support of pipes etc. (author)