Heat and Mass Transfer and Gas Distribution in a Steam-Water Volume with Noncondensable Gas.

Heat and mass transfer and gas distribution in a nonequilibrium steam-water volume with a phase separation level containing a noncondensable gas are considered. These processes relate primarily to the steam–gas pressurizer (SGP) of the integral reactor and determine the behavior of the SGP in normal and emergency modes. Similar processes occur in a pressurized water reactor and in a containment volume at the final stage of emergency regimes with loss of coolant. For small-power reactors of the RITM-200 type with a gas pressurizer, it is necessary to take into account the phenomena associated with the behavior of noncondensable gases. A brief description is given of the GARRIC 2.2 computer program for calculating the distribution of noncondensable gases in the primary circuit and the characteristics of the SGP of a pressurized water reactor of an integral layout. The description of the processes of heat and mass transfer and gas distribution is based on the results of experiments carried out on SGP models in a wide range of parameters and gas contents. Calculation of mass transfer, including surface evaporation and steam condensation, and gas transfer on the surface is carried out using the analogy model of heat and mass transfer under conditions of natural convection of the medium. The results of the verification of the GARRIC 2.2 program on the experimental data obtained in the study of vapor condensation on the walls, evaporation on the free surface of water, and gas distribution in the steam–gas volume at full-scale parameters are presented. The GARRIC 2.2 program was certified by Rostekhnadzor in 2014. [ABSTRACT FROM AUTHOR]