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RHR

  1. (RHR, BC) – RHR 7 Modes:
    • LPCI
    • TORUS COOLING
    • TORUS/DRYWELL SPRAY
    • SHUTDOWN COOLING
    • FUEL POOL COOLING ASSIST
    • CONTAINMENT FLOODING
    • ALTERNATE INJECTION
  2. (RHR, BC) – Purpose of LPCI - Restore and maintain Rx vessel water level following a LOCA. This mode of RHR is an ECCS mode of operation
  3. (RHR, BC) – Purpose of TORUS COOLING - Removes energy from the torus to restore/maintain the pressure suppression capability of the primary containment.
  4. (RHR, BC) – Purpose of TORUS/DRYWELL SPRAY - Remove energy from primary containment to restore/maintain the pressure suppression capability of the primary containment
  5. (RHR, BC) – Purpose of SHUTDOWN COOLING - Removes decay and sensible heat from the fuel and nuclear boiler system.
  6. (RHR, BC) – Purpose of FUEL POOL COOLING ASSIST - Alternate means to remove decay heat from the spent fuel pool (with the installation of flow orifice).
  7. (RHR, BC) – Purpose of CONTAINMENT FLOODING - Provide a flow path for an emergency source of water (service water) if post accident conditions require containment flooding.
  8. (RHR, BC) – Purpose of ALTERNATE INJECTION - Provides a flow path for an emergency source of water (service water) for RPV level or flooding when other sources are not available.
  9. (RHR, BC) – Injection Valve Open Permissive Pressure
    450 PSIG
  10. (RHR, BC) – Pump Shutoff Discharge Press
    366 PSIG
  11. (RHR, BC) – Pump Normal Flowrate
    10,000 GPM each @ 171 psig
  12. (RHR, BC) – Minimum Flow Valve Open
    < 1,250 gpm AND Pump brkr Closed AND 10 sec. T.D.
  13. (RHR, BC) – Minimum Flow Valve Close
    > 1,270 gpm AND 4 sec. T.D.
  14. (RHR, BC) – ADS ‘Pump Running’ Permissive
    125 PSIG Pump Discharge Pressure (need one pump)
  15. (RHR, BC) – Start Time Delay w/o LOP
    • A&B = 0 sec.
    • C&D = 5 sec.
  16. (RHR, BC) – Start Time Delay w/ LOP
    A/B/C/D = 0 sec. (after EDG brkr closure)
  17. (RHR, BC) – SDC Valves closure/permissive
    82 PSIG RPV / +12.5” RPV
  18. (RHR, BC) – The RHR pumps will auto start in the LPCI mode of operation on 2 initiation signals:
    • Hi Drywell Pressure: 1.68 psig
    • Low Reactor Level: -129”
  19. (RHR, BC) – The LPCI injection valves (F017A, B, C, D) will NOT open without:
    • a valid initiation signal as sensed by it’s channels logic
    • AND a low Rx pressure condition of <450 psig
  20. (RHR, BC) – Suction path/Pump interlock
    The RHR pumps trip with no available suction path.
  21. (RHR, BC) – C and D pump suction source
    The C & D pumps can only take suction from the torus
  22. (RHR, BC) – Which pumps can be aligned for SDC or FPC?
    A and B pumps
  23. (RHR, BC) – What is needed to align A and B pumps for FPC?
    In order to align RHR for fuel pool cooling, the suction valve trip interlocks must be overridden using switch S66A(B) on C617(8) in the lower control equipment room.

    A flow restriction orifice must be installed to limit flow
  24. (RHR, BC) – Pressing STOP pb after LOCA, then LOP happens. Response of the pump?
    • Depressing the RHR pump STOP will o/r a pump auto start signal and trip the pump.
    • This o/r is lost if the associated 4.16kv bus power is lost.
    • When the EDG restores power to the bus, the pump will start.
  25. (RHR, BC) – What are the torus suction valves (F004A/B) interlocks?
    F004(A/B) are interlocked such that they CANNOT be opened unless the RHR pump shutdown cooling suction valve (F006A/B) are full closed and vice versa. (Prevents draining the Rx vessel to the torus.)
  26. (RHR, BC) – Interlock to open the SD cooling suction valve (F006):
    • All must be CLOSED
    • (All communications to the torus):
    • F004 – RHR pump torus suction
    • F024 – Pump test return to the torus
    • F027 – Torus spray isolation (This interlock is not reciprocated by F027)
  27. (RHR, BC) – F008/9 OPEN interlock:
    Reactor pressure must be <82 psig regardless of where these valves are controlled
  28. (RHR, BC) – The following valves will CLOSE in response to ANY of the conditions listed which exist concurrently in [Ch A & B of NS4] or [Ch A Manual isolation]:
    • F009 SDC I/B Suction
    • Low RPV Level 3 (+12.5”) (Needs 2 transmitters)
    • High Rx Pressure (82 psig (rising) (SINGLE coincidence – existing in Channel A or B)
    • F079(A/B) RHR Sample I/B Isolation, F049 RHR D/C TO RW I/B Isolation
    • Low RPV Level 3 (+12.5”)
    • High Drywell Pressure (1.68#)
  29. (RHR, BC) – The following valves will CLOSE in response to ANY of the conditions listed which exist concurrently in [Ch C & D of NS4] or [Ch D MANUAL isolation].
    • F015(A/B)* SDC return valves; F008* SDC O/B suction.
    • Low RPV LEVEL 3 (+12.5”)(needs 2 transmitters)
    • High Rx Press. (82 psig (rising)) (single coincidence - existing in Channel C or D)
    • F080(A/B) RHR sample O/B isolation; F040, RHR D/C to RW O/B isolation.
    • Low RPV LEVEL 3 (+12.5”)
    • High Drywell pressure (1.68#)
  30. (RHR, BC) – SDC valve response if control is at the RSP
    F015(A/B), F008, F009 will not reclose if Rx pressure rises above 82 psig.
  31. (RHR, BC) – When does min flow valve OPEN (F007)?
    • F007's are normally open.
    • >1250 gpm for >10 sec with the pump breaker closed the valve will re-open.
  32. (RHR, BC) – When does min flow valve CLOSE (F007)?
    Flow >1270 gpm with a 4 sec TD
  33. (RHR, BC) – Min flow valve (F007) caution when pump is stopped?
    If the min flow valve is closed when the RHR pump is stopped (breaker opened), the valve will remain closed and will have to be positioned by the operator.
  34. (RHR, BC) – RHR Hx B/P (F048) auto operation from MCR and RSP/MCC:
    • MCR –
    • F048 receives an OPEN signal upon receipt of a LPCI initiation signal.
    • Signal is sealed in for 3 minutes
    • RSP/MCC –
    • Control of F048B from the RSP or control of F048A from it's MCC bypasses the 3 minute interlock
    • removes all automatic operation of these valves.
  35. (RHR, BC) – The RHR loop test return valves F024(A/B) & F010(C/D) response to an automatic or manually initiated LPCI injection signal
    F024(A/B) & F010(C/D) valves will close
  36. (RHR, BC) – What are the F024(A/B) OPEN interlocks:
    • F024 cannot be opened unless the associated F006 valve is full closed, and vice versa (prevent draining the reactor to the torus)
    • F024 can be reopened by using the Auto Close Override provided the initiation signal is in and F017 is shut.
  37. (RHR, BC) – The RHR torus spray isolation valves (F027's) automatic response
    F027’s will automatically close in response to a LPCI initiation.
  38. (RHR, BC) – How can the F027’s be reopened following LPCI initiation:
    • F027s can be opened by using the AUTO CLOSE OVERRIDE
    • The following must be satisfied in order to open using the AUTO CLOSE OVERRIDE:
    • Initiation Signal Present
    • DW Pressure > 1.68#
    • F017 Closed
  39. (RHR, BC) – What is a F027 interlock with F006?
    F027 must be full closed to allow the opening of F006 (However, F027 does not reciprocate this interlock).
  40. (RHR, BC) – The LPCI injection valve #s
    F017
  41. (RHR, BC) – The LPCI injection valves (F017's) will auto open in response to an initiation signal if the following conditions exist:
    • LPCI initiation signal present in proper channel.
    • Power available on proper RHR pump bus (no UV).
    • Rx pressure is < 450 psig. (Sensed by Lo D/P across F041 LPCI check valve)
  42. (RHR, BC) – The LPCI injection valves (F017's) can be overridden by:
    The auto open signal can be overridden if the AUTO OPEN OVERRIDE P.B. is depressed.
  43. (RHR, BC) – The LPCI injection valves (F017's) must be full closed to open:
    The injection valve must be full closed with a LPCI initiation signal present in order to open F027, F024, or F016/F021.
  44. (RHR, BC) – Containment spray valves and when can open
    (F016 & 21) cannot be opened simultaneously unless all conditions are present to allow for a containment spray.
  45. (RHR, BC) – The following must be met in order to spray the drywell/torus:
    • A valid LPCI initiation signal is present.
    • High drywell pressure > 1.68 psig.
    • LPCI injection valve (F017's) full closed. (Auto Open Ovrd)
  46. (RHR, BC) – The RHR pumps are auto started in response to a valid initiation signal w/Offsite Power:
    • A & B pumps start immediately.
    • C & D pumps start after a 5 second T.D. (prevents overcurrent condition on the station service transformers).
  47. (RHR, BC) – The RHR pumps are auto started in response to a valid initiation signal w/o Offsite Power:
    • All 4 pumps start immediately if:
    • the D/G output breaker is closed (start permissive for C & D pumps only)
    • AND bus voltage is reestablished.
  48. (RHR, BC) – On Initiation, the system aligns for the LPCI mode, what is the sequence:
    • Pumps start
    • Test return valves close (F024 and F010)
    • Torus spray valve closes (F027)
    • Heat exchanger bypass valve opens (F048) (3 minute seal in upon initiation)
    • Injection valve (F017) receives “1/2” of open logic (requires RPV pressure <450#)
  49. (RHR, BC) – During SP cooling, what is a caution with a LOCA?
    During SP cooling, the HX bypass valve is closed. If another LOCA signal comes in while you are in this lineup (without resetting the first), the valve remains closed.
  50. (RHR, BC) – What is bypassed after shutdown cooling is placed into service?
    The Suction Path Trip for the RHR pump is bypassed. This is done in SO.BC-2 immediately AFTER the pump start, so, it can be assumed that if you are in SDC mode, the pump suction trip no longer exists. Additionally, the interlock is removed just BEFORE removing the pump from service.
  51. (RHR, BC) – In IO.ZZ-5 (Cold Shutdown to Refueling), RHR actions:
    The NS4 isolations to F008/9/15(A,B) are defeated immediately after the head is removed (just before flood-up) and are restored immediately before the head is installed in IO.ZZ-1 (Refueling to CSD).
Author
NuclearGuy
ID
352334
Card Set
RHR
Description
RHR
Updated

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