Experience of commissioning of the V-392M reactor plant passive heat removal system

Abstract

The paper considers structural features of components in a passive heat removal system (PHRS) used for the first time in Russia in the VVER-1200 reactor. It describes the design deficiencies of the system's air gate valves and regulators detected in the process of pre-commissioning activities and making it impossible for the system to perform its design functions. The deficiencies are explained by unpredictable effects of the working fluid's thermodynamic processes on the movable parts of the equipment. The equipment deficiencies were eliminated through the installation of additional equipment retainers which respond to the system actuation and by additional debugging of components. The retainer allows keeping the air gate valves fully opened and prevents their uncontrolled closure under the action of a rapidly ascending hot air flow inside the PHRS shell. During the commissioning stage of Novovoronezh NPP II's unit 1, following an update of the equipment design, the PHRS proved to be indispensible as the means to remove the reactor core heat in conditions of an unexpected scram and has confirmed its efficiency as part of an integrated test at 75% of the reactor power. The PHRS heat exchanger total heat removing capacity was over 100 MW at the ambient air temperature of –13 °C, and the time for the PHRS to reach full capacity did not exceed 90s, which corresponds to the system's design performance.

Keywords

• AES-200 design
• V-392M
• VVER-1200
• Passive heat removal system
• Air gate valve
• Regulator
• Pre-commissioning