Experimental estimation of the effect of contact condensation of steam-gas mixture on VVER passive safety systems operation

Experiments were conducted on the test facility with parameters typical for the primary cooling loop of the reactor facility 24 h after the accident initiation for different concentrations of gas in the steam-gas mixture. Nitrogen and helium, which replaces hydrogen for the purposes of safety assurance, were used as the non-condensable gases. It was established according to the results of experiments that the increase of concentration of non-condensable gas within the volume of HA-2 hydro accumulator model up to 45% leads to the reduction of intensity of contact condensation of steam from the steam-gas mixture by ∼29% in the experiment with nitrogen and by ∼57% in the experiment with helium. The obtained experimental data can be used for numerical simulation of emergency processes in the VVER reactor facility during operation of passive safety systems taking into account the removal of steam-gas mixture from steam generator by supplying the subcooled liquid jet into the volume HA-2 accumulator tanks.