VACCUM PULLING

• Close RH vents (IP turbine and LP turbine direct coupled if RH vents not closed then air from atmosphere is coming in the condenser via IP and LP turbine) & close vacuum breaker valve (It directly connected condenser) and Water sealing (water is used as a seal fluid for vacuum baker, condensate system and feed water system valve water first taken from hot well make up line and further condensate system line before RC valve) is available.
• Ensure condenser water box is charged (because of if heat is coming from different source like gland seal gland steam condenser are picked from CW water).
• Ensure that ACW booster pump is running and cooling water is available to vacuum pumps coolers ().
• Ensure that one CEP is in service and min condensate flow is established.
• Check both vacuum pumps are available and are ok at local. Line up vacuum pumps as specified in vacuum pumps operating instructions
• Open Aux. seal steam drains on turbine side and open seal steam root valve at Aux. Steam header. Slowly charge the seal steam line after ensuring sufficient heating of the line
• Start one vacuum pump and observe vacuum.
• As the vacuum reaches 0.7 ksc, charge seal steam and maintain a pressure of 200 mm of WCL.
• Start GSEB & open LP turbine exhaust hood spray valve.
• Charge seal steam to turbine glands and maintain 200 mm of WCL pressure.
• Start another vacuum pump also if required.
• Ensure that necessary vacuum of 0.1 ksc is achieved.

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