Vacuum Killing

PROCEDURE FOR KILLING VACUUM IN CONDENSER

PREREQUISITES : 
Before Killing Vacuum ensure the following points .

• Boiler Stop Valves are closed & they are manually tightened .
• Isolate the power supply for MS SV ( total 6 nos )
• MS line is completely depressurised by opening HP/LP Bypass .
• HPBP Spray is isolated by closing manual valve at 8.5 Mtr .
• TDBFP A/B supply team is isolated .
• D/A High level is not maintained & condensate passing to D/A is stopped by closing necessary valves .
• MS Atmospheric drains are open . All MS/CRH/HRH drain to UFT are open & to condenser are closed .
• TG is on barring gear or barring gear stalled .
• Kill cond vacuum through SGC Shutdown programme .
• Close Vacuum p/p suction v/v
• Stop vacuum pump . / Stop recirculation pump.
• Open Vacuum Breaker.
• At Vacuum –0.2ksc isolate gland seal steam to turbine by closing the CV .
• Stop seal steam exhauster.
• Switch off SLC Vac Pump / Isolate valve gland sealing .
• Close the 8.5 Mtr GS steam isolation valve & Keep the UFT manual drain open .
• Close the GS supply valve both HT / LT (Normally remain closed) at APRDS floor .
• Ensure the Seal steam Hdr Drain MAL 81 & Supply steam drain MAW11 are in open position .
• Monitor the seal steam supply & Seal steam Hdr ( F/ R ) temperatures which will indicate any passing .
• Ensure SLC Drain is ON & Turbine drains are open a s per logic
• Monitor the Turbine Casing DT whiv\ch will indicate the type of cooling going on .
• Monitor barring gear speed reduction after vac killed . It should be around 70 rpm .
• Hotwell Normal level is to be maintained. (-100 mm)
• Monitor D/A level it should not Over flow to Hot well . (170mm<level<300 mm)
• Let both CW passes be in charged condition. Till HPC temp < 290 0 C. Both pass should be charged & Both CW pump should run .
• Observe drop in turbine barring speed) i,e see that speed remains around 70 to 80 rpm. If speed drops below 70 rpm inform TMD immediately.
• When speed stabilizes, note down jacking oil pressures at inlet to all 7 bearings along with TMD .