RELAP5 analysis on the safety depressurization and vent system transient

This study developed the analysis model for RELAP5 by comparison with experimental data. In the development of RELAP5 analysis model, a few adjustments were taken. Thus, the water level was increased for the good agreement of the rate of pressure decrease, and the manipulation of valve also adjusted for the good agreement of the minute behavior in earlier transient. This model was applied to prototypic transient and air clearing. In the analysis of prototypic SDVS transient of KNGR, the rate of pressure decrease in pressurizer was revealed to be 0.2875 MPa/sec, which is faster than the above experimental data, and the pressure of sparger was about 4 MPa. In the application to air clearing transient, the duration time of air clearing of which experiment will be conducted was revealed to be 1 second, and the maximum pressure at the sparger was turned out to be 0.6 MPa at the end of air clearing. (author)