Experimental study of lead coolant level changes during gas bubbling through nozzles of various geometries

The article presents the results of an experimental study on changes in the free surface level of a high-temperature lead coolant during the bubbling of argon and hydrogen through nozzles of various geometries in a stationary tank depending on the duration of gas injection. The experimental procedure consisted of multiple stages, each involving injecting gas into the liquid lead bulk using a compressor for 3 hours, with the level measurements taken hourly, which was followed by a one-hour period without bubbling, after which the level was measured again. Experiments were conducted with three nozzle types and two different gases: argon and hydrogen. The control volume of lead was also varied during the experiments. The results indicate that with relatively small volumes of lead coolant, no significant change in the free surface level occurs due to gas saturation of the coolant. This effect was absent for both argon and hydrogen — gases used in nuclear reactors with heavy liquid metal coolants. Furthermore, varying the gas injection method by using different nozzle geometries also failed to produce a significant change in the free surface height. The findings of this study may be useful for designers of reactor systems employing heavy liquid metal coolants with a free surface. Subsequent work may involve experiments with larger lead volumes, the use of more advanced level measurement techniques, and monitoring the flow rate of gas injected into the lead coolant.