An experimental study of ingress-of-coolant accident in fusion reactors

An experimental study has been performed to investigate the effects of various parameters upon the pressurization rate in a low-pressure enclosure to simulate an ingress-of-coolant accident in tokamak fusion reactors using a superheated liquid as the primary coolant. A superheated water jet is impinged on a hot cylindrical block in an evacuated enclosure and the time variations of the hot surface temperature and enclosure pressure are recorded. The varied parameters are the material of the block, impinging water temperature, distance from the nozzle to the block, and mass flow rate of the ingressing water. The pressurization rate appears to be independent of the hot block material. It increases with the increase of the mass influx rate and temperature of the water. The dependence of the rate of pressurization on the jet transit time from the nozzle to the block appears to be weak, showing only a slight increase at the shorter transit time. Future works will focus on acquiring more data and quantifying the effect of heat transfer from the hot block on the pressurization rate.