Abstract
The essential technological distinctions of the Novovoronezh NPP-2 (NV NPP-2), equipped with passive safety systems, determine some specifics in the character of accidents with the coolant leaks from the reactor primary circuit and the refusal of active part of the emergency core cooling system (ECCS). In the case of an accident with depressurization of the reactor primary circuit, the system of passive heat removal (PHRS) ensures the transition of steam generators (SG) into the mode of steam condensation. As a result, a condensate comes to the core, providing its additional cooling. Upon the steam generators operation in condensation mode, the significant influence exerts the presence of non-condensable gases in the primary circuit. The accumulation of the non-condensable gases in the steam generator pipelines results in the deterioration of its condensation ability. The design decisions considered in the project enable the removal of non-condensable gases in the composition of gas-steam mixture coming from the SG into the hydroaccumulators of second stage system (HA-2) to be guaranteed. For the experimental verifying of the sufficiency of such mixture outflow from SG into the HA-2 system to maintain the SG condensation power, the large-scale test facility HA2M-SG was constructed in IPPE. The experiments dealing with the study of condensation mode of SG operation under the ingress of mixture of steam with non-condensable gases into pipelines and synchronous outflow of gas-steam mixture were carried out at the test facility. The experiments were carried out by the method of steady states at the steam pressures of 0.35-0.36 MPa.
