Investigation of the Cooling of Water-Cooled and -Moderated Reactors Based on Electricity Generation Via Residual Heat in Emergency Situations with De-Energization

Abstract

Safety enhancement of NPP power units with water-moderated and -cooled reactors on the basis of installation of additional multifunctional low-power steam-turbine generators is studied. It is shown that the parameters of the primary and secondary loops change as the VVER-1000 reactor is cooled via the use of the residual heat in the core to generate steam that serves as the working body for a low-power steam-turbine plant. Uninterrupted power supply for the NPP’s own needs is achieved on account of the fact that in normal and emergency regimes the low-power turbine unit supplies electricity to power consumers during cooldown of a reactor in an emergency situation with a blackout. It is shown for the example of 6 and 12 MW turbine units that the residual heat from one VVER-1000 reactor is sufficient to cool two such reactors for 72 h with de-energization of the NPP and depressurization of the primary loop in one of them.