Coolant cavitation in dynamic containment loading

Abstract

After a brief introduction to the subject of cavitation in subcooled liquids and a survey of what is known regarding the key parameters in the cavitation process for water and for sodium, the basic equations of the SIMON cavitation model for use with Lagrangian containment codes and the assumptions behind them are reviewed. Some calculations using this model are then presented which show the dissipative effect of cavitation both in uncavitated liquids transmitting tension waves and in cavitated liquids transmitting pressure waves. The cavitation which develops when pressure waves are reflected at free surfaces is also examined, and some calculated results are compared with an experiment involving this phenomenon found in the literature. The role of cavitation in the containment loading process is then discussed, and examples taken from model test calculations are adduced to show that cavitation occurs at all stages of the loading process and involves a high proportion of the total liquid volume. Again by example the point is made that in certain simple circumstances a crude pressure cut-off model of cavitation is adequate but that for other major aspects of the containment loading process such as roof impact pressures and structural deformations a more refined model is necessary.