Experimental investigation on hot water seal over an analogous U-shaped device

A scale ration of 1:1 test loop was constructed to investigate the water seal formation phenomenon in front of pressurizer safety valve in nuclear plant. The water seal features were investigated under the condition of pressure ranging from 0.15 to 0.55 MPa. The test was placed in a room with air conditioner to make sure the temperature in the room is keep relative stability thermal conditions, the temperature in the room may fluctuation between 20° and 25°. Water level oscillates in the process of water seal stabilization, the experimental data fit very well with the proposed model in the paper. The water seal formation time reduced significantly with pressure increasing and air concentration decreasing. Refilling of the pipe is much more rapid than the initial one due to a lower content of non-condensable gases remaining in the steam. Finally, the water seal starting point judgment method has been put forward in this paper.