Card Set Information

2015-12-01 15:29:36
AFW advanced systems

Show Answers:

  1. What must be done to AFW system if T-2 level <=7.5%?
    All pumps must be manually tripped if running and placed in manual to prevent start on AFAS.

    If in ELAP, do not trip P-8B until you get to 0%.
  2. Aux feed controls from C-33?
    • HIC-0727/0749/0736A/0737A flow control
    • can operate flow control in manual only
    • in auto passes signal from FIC in control room to valve
  3. AFW motor amp limitations
    • P-8A-112 amps
    • P-8C-99 amps
    • ensures full load current will not be exceeded
    • -prevents winding overheating and insulation degradation
  4. Why do we monitor drain traps on P-8B?
    malfunction of traps could make P-8B inoperable
  5. What happens to B AFW pump on loss of D-11-1?
    CV-0522B opens
  6. What is required to reset AFAS?
    Both S/Gs must be greater than 30% level
  7. When are FIC-0736A/0737A C AFW pump flow controllers considered operable?
    • in cascade
    • in auto
    • in PF
    • not operable if FIC of HIC is in manual
  8. How do CV-0727/0749/0736A/0737A aux feed flow control valves fail?
    • fail open on loss of air (air to close)
    • equipped with manual operators
    • CV-0727/-0749 have N2 backup
    • CV-0736A/0737A no N2 backup
  9. How do we prevent water hammer in AFW system?
    check valves are installed in AFW lines near the S/Gs
  10. Aux feed controls from C-150?
    • P-8B can open and close CV-0522B
    • -low suction pressure trip lost
    • CV-0727/0749
    • -can control flow to A/B S/G from A/B pumps
    • FI-0727B/0749B
    • -flows to A/B S/G from P-8A/B
    • must take transfer switches to AHSP
    • also have WR S/G levels
  11. Purpose of PF pushbutton on FIC-0737A/0736A?
    • transfers control to the 1.5" bypass valves and will shift controller mode from cascade to auto-locks in auto
    • if in PF mode and get an AFAS will switch to cascade
  12. Normal system alignment for aux feed system?
    Normally aligned for fully automatic operation. When at least 2 S/G level safety channels associated with a S/G reach 30%, an AFW pump starts and its associated flow control valves open to deliver the required flow to both S/Gs.
  13. Limits on operating P-8C in recirc mode?
    • P-8C operating in recirc mode should be limited to < 2 minutes and shall be limited to < 5 minutes.
    • -recirc line to T-2 is not sufficient to protect the pump
    • P-8C should not be run with a total flow of <75 gpm to the S/Gs.
  14. LCO 3.7.5 Aux Feedwater System actions for <100% of the required AFW flow available to both S/Gs
    Note: LCO 3.0.3. and all other LCO required actions requiring Mode changes or power reductions are suspended until at least 100% of the required AFW flow is available

    • Action C1: Initiate action to restore 1 AFW train to operable status
    • -immediately
  15. How do CV-0736/0737 flow control bypasses fail?
    • fail closed on loss of air
    • -air to open
    • equipped with manual operators
  16. AFW pump start sequence on AFAS?
    • P-8A after 2.5 seconds if:
    • -AFAS and
    • -P-8A control switch in auto and
    • -2400 V power available

    • P-8C
    • -starts w/ above conditions and
    • -P-8A not delivering flow to either S/Gs or not running
    • --1/2 logic to both S/G flow <100 gpm (1/2 taken twice)
    • --30.5 second time delay

    • P-8B valve opens on above and
    • -P-8A not delivering (112.5 sec) and
    • -P-8C not running or <100 gpm
  17. AFW pump power supplies
    • P-8A-C bus
    • P-8C-D bus
  18. LCO 3.7.5 Aux feedwater system
    LCO 3.7.5.: 2 AFW trains shall be operable

    APP: Modes 1,2,3 and Mode 4 when S/G is relied upon for heat removal

    • Notes:
    • Only 1 AFW train, which includes a motor driven pump, is required to be operable in MODE 4
    • The steam driven pump is only required to be operable prior to making the RX critical
    • 2 AFW pumps may be placed in manual for testing, for a period of up to 4 hours

    LCO 3.0.4.B is not applicable (risk assessment)
  19. Design flow of AFW pumps?
    • P-8A design flow of 415 gpm
    • -capable of delivering the minimum required flow for decay heat removal up to 1000 psia in the S/Gs

    • P-8C design flow of 330 gpm
    • -it will deliver to minimum required flow for decay heat removal if S/G pressure is maintained at or below 900 psia or if all PCPs are secured

    P-8B has design flow of 415 gpm
  20. AFW pump trips
    • low suction pressure trip 2/3 logic 5 second delay
    • -P-8A/B setpoint is 6.7 psig
    • --switches from Y-10 but swap to Y-30
    • -P-8C setpoint is 8.0 psig
    • --switches powered from Y-20
    • ---must trip handswitches or close CV to reset

    • P-8B trips on overspeed (3845-3916 RPM)
    • P-8A/C trip on overcurrent and load shed
  21. Aux Feed Actuation System (AFAS)
    • provides auto AFW pump starting on low level in either S/G @ 30% 2/4 logic
    • sensors powered from Y-10/20/30/40
    • loss of power to sensor channels causes that channel to trip
    • -loss of 2 preferred AC buses initiates AFAS
  22. AFAS actuation channels
    • Channel A (left train)
    •   -D-11-1 
    • Channel B (right train)
    •  -D-21-2
    • loss of actuation power prevents actuation channel from initiating an AFAS
    • if lose D-11-1 P-8B auto starts and flows 165 gpm to the S/Gs
  23. When are AFW controllers FIC-0727/0749 considered operable?
    • in cascade OR
    • if in auto and no main feedwater in service and S/G levels and PCS temperatures maintained with in bands required for decay heat removal
    • not operable if FIC or HIC is in manual
  24. What is required to meet 100% of required AFW flow per LCO 3.7.5?
    One hundred percent AFW flow (that assumed in the safety analyses) can be provided by any one OPERABLE AFW pump and an OPERABLE flow path to each steam generator.