OREANDA-NEWS. March 05, 2011. By order of Saint Petersburg Research and Design Institute “Atomenergoproekt” OJSC (SPAEP OJSC) at the large-scale stand in Sosnovy Bor FSUE NITI of A.P.Alexandrov has tested the model of PCHRS passive security system (Passive Containment Heat Removal System) together with a large-scale model of containment of an NPP with VVER.

The PCHRS system has been developed by SPAEP OJSC for a nuclear power plant of the NPP-2006 project being constructed now at LNPP-2 site, Sosnovy Bor city of Leningrad region, and designed for heat removal from the containment in case of an accident with depressurization of the primary coolant circuit.

The necessary conditions for PCHRS testing at the large-scale stand are provided due to steam supply by the institute boiler house to the containment model.

Efficiency of heat exchange condensers of PCHRS under different pressure and temperature conditions inside the containment model and different coolant flows in the circuit for heat removal from PCHRS heat exchange condensers, as well as with different composition of the heat exchange condensers operating elements was checked.

Pilot research of helium distribution (as hydrogen simulator) in the premises inside the containment both in the cold conditions and after steam supply to the containment at operating elements of PCHRS heat exchange condenser elements was simultaneously carried out.

Experiments with supply of helium to the containment model are performed in order to justify hydrogen safety in case of severe accidents. These experiment results are used for verification of integral codes used for safety justification of NPPs with VVER and three-dimensional computer codes describing spatial thermal-hydraulic processes in the premises of NPP containments.