Analysis of the thermal-hydraulic parameters of VVER-1200 due to loss of coolant accident concurrent with loss of offsite power.

Abstract This paper aims to evaluate severe accident in VVER-1200. The consequences of severe accident depend greatly on containment safety features and its performance in retaining radioactive material. The specific type of LOCA includes hot leg or cold leg break in the primary coolant circuit. For both simulations a loss of offsite power is also initiated after 500 seconds. It shows that the Reactor Cooling System (RCS) pressure drops from 155 bars to below 5 bars in both the cases to reduce RCS leakage. Reactor Core Thermal Power, Nuclear Flux Power and Turbine Load fall significantly after 23.5 seconds because of the occurrence of Reactor Trip. Both HA-1 and HPI are activated to prevent Core damage. The flow of HPI drops to zero after the loss of offsite power. The temperature of the fuel falls below 200 ºC within 150-200 seconds of the malfunction in both the cases. The corresponding pressure, temperature, void fraction of reactor etc. are analysed in this paper. The results obtained satisfactorily meet all PSAR (Preliminary Safety Assessment Report) data regarding Loss of Coolant Accident (LOCA). The results provide useful information about safety features of VVER-1200 in case of Loss of Coolant Accident (LOCA) concurrent with loss of offsite power. [ABSTRACT FROM AUTHOR]