The problems occurred in vacuum system during debugging and restarting after major and minor repairs

as well as in normal operation of 350 MW unit manufactured by Mitsubishi Corporation

such as exhaust obstruction of the vacuum pump

without opening the sealing water of air valve in the heating system

clog in the condenser

air-leakage from the steam air heater system into the condenser

and water drain valve of the low-pressure heater being blocked by impurities etc.

have been analysed

and defects existing in the equipment and system being handled

ensuring operation of the vacuum system to be normal

enhancing economic behavior and safety of said unit.