Main Condenser/SJAE Flashcards
What is normal main condenser vacuum and at what setpoints will trips/isolations happen?
25” - Maintain vacuum above this value
24.8” Hg Vac - Main Condenser Low Vacuum Alarm
22.3” Hg Vac - Main Turbine Trip & U2 RFPT Trip
17” Hg Vac -U1 RFPT Trip
10” Hg Vac - MSIVs close (Group 1 Isolation)
7” Hg Vac - Main Turbine Bypass Valves Close
5 psig - internal pressure on condenser causes rupture discs on LP & RFP turbines to rupture
Read questions carefully! - With MSIVs shut at 10” Hg, Bypass valves will not be able to control Rx pressure, even if still open
What is the limit for operation of the mechanical vacuum pump? Where does it draw suction from and discharge to?
- MVP also takes suction on main condenser but it discharges directly to stack via a separator tank and a 1.75 min holdup volume (does not go through recombiner, off gas condenser or charcoal beds!)
- MVP should not be operated w/ Rx power above 5% due to 2 major reasons
1) > 5% - amount of radioactivity evacuated from main condenser is too high to release directly to the environment due to short 1.75 min hold up volume (MVP flow is NOT filtered)
2) Sufficient quantities of H2 & O2 are present in the main condenser that, when heated in pumping process, could cause a H2 explosion
Trips on Main Steam Line High Radiation (3x Normal) (usually in @ < 20% RTP)
What are the interlocks associated with the SJAE 1st stage steam supply valves 2N11F008A/B (1N11F036A/B & 1N11F103A/B)?
Closes if
- Upstream steam supply pressure is < 180 #
AND
- Condensate pressure from the 1st & 2nd stage return of the intercondenser is < 100 #
OR
- Control switch is taken to OFF
What are the interlocks associated with the SJAE 2N22F004A/B (1N22F011A/C) - Suction Valves for the 1st stage Air Ejector suction line from the condenser?
Close if 3rd stage steam flow is < 2000 lbm/hr
What are the interlocks associated with the SJAE 2N22F005A/B (1N22F505A/B) 1st stage suction valve from Main Condenser?
Closes if 1st stage steam supply pressure after PCV, 2N11F008A/B (1N11F036A/B) is < 30 # (120 #)
What are the power supplies for the Mechanical Vacuum pump and the Steam Packing Exhauster?
U2 Mechanical Vacuum Pump - 2R23-S001 (600 “A”)
U2 Steam Packing Exhauster - 2R24-S005 (208 MCC “2A”) from 600 VAC B
U1 Mechanical Vacuum Pump - 1R23-S002 (600 “B”)
U1 Steam Packing Exhauster - 1R24-S005 (600 MCC “1A”) from 600VAC AA
What are the interlocks associated with the SJAE 2N22F018A/B - SJAE intercondenser drain valve?
Closes if 1st stage intercondenser vacuum decreases to < 12” of Hg
What are the interlocks associated with the SJAE 1N21F411A/B - SJAE intercondenser drain valve
and 1N21F206A/B/C/D - SJAE drain tank eductor condensate supply valves?
Closes if 1st stage intercondenser pressure decreases to < 15” of Hg
What provides seal steam at low power and at high power? What systems is seal steam provided to?
Seal Steam applies sealing steam to the main turbine, RFPT, and various turbine valves (main stop, control, combined intercept, and bypass valves)
Supplied at light loads to prevent air leakage along the turbine shaft
- < 30% power sealing steam prevents air from being drawn across the seals and into the turbine
- > 30% power the turbine is self-sealing
Pressure inside turbine casing is > sealing steam pressure & turbine supplies sealing steam
Seal Steam also prevents steam leakage into Turbine Bld
What causes the Mechanical Vacuum Pump and Steam Packing Exhauster to trip?
Trip on Main Steam Line High Radiation (3X normal) –trip in service only < 20% RTP
(High-High-High or Inop Trip of either A or C and B or D MSL Rad Monitor NUMAC)