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Flashcards in Reduced Inventory / Mode 6 / Outage Deck (40)
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State the purposes of 40OP-9ZZ16 RCS Drain Operations to include minimum allowed level.

  • Places the RCS in a drained condition. Between 10% LPZR [117’] down to minimum level allowed at Mid-Loop [101’ 6”].
  • Supports plant activities that require an RCS drain down be performed, with or without fuel in the Vessel.
  • Restores the RCS level within the PZR, in preparation for RCS fill and vent.


State the equipment, limits or classification that correspond to the following levels:

  • 149’ 
  • 137’ 9” 
  • 137’ 4” 
  • 131’ 5”
  • 122’ 1”
  • < 117’ 
  • < 114’ 
  • < 111’ 
  • < 103’ 4” 
  • < 103’ 1” 
  • 101’ 6” 

  • 149’ PZR Manway
  • 137’ 9” (admin pool level for ALARA)
  • 137’ 4” (≥ 23’ above vessel flange, LCO 3.9.6 when moving fuel or fuel in vessel)
  • 131’ 5” 50% PZR level
  • 122’ 1” (≥ 23’ above top of fuel in vessel, LCO 3.9.7 when moving CEAs with fuel in vessel)
  • < 117’ Partial Drain (LPZR 10%)
  • < 114’ Lowered Inventory / Vessel Flange level
  • < 111’ Reduced Inventory
  • < 103’ 4” SG tubes drained, not available for DHR
  • < 103’ 1” Mid-Loop entered (Top of Hot Leg), SG tubes begin to drain.
  • 101’ 6” Minimum Level for Mid-Loop Operations (2” above Hot Leg Centerline)


What level indication is used for Hot and Cold calibrated Lpzr?

What must be done if > 3% deviation is noticed?

  • LT-110X/110Y (Hot cal LPZR) and LT-103 (Cold cal LPZR)
    • LT-103 and LT-110Y share a common variable leg tap
    • 3%: Max indicated level deviation
    • Backfill reference legs if levels deviate or are suspect


State the operating characteristics associated with RWLIS NR and WR indications.


Include ranges, when one or both channels are required, power supplies and what is required if loss of CR indications is experienced.

  • Both RWLIS NR and WR start at 99’ 7” (bottom of hot leg)
    • NR between 99’ 7” – 102’ 11”
    • WR > 102’ 11”
    • One channel required in Partial Drain
    • Two channels required in R/I and M/L
    • Indication is automatically compensated for SDC flow (signals from FTs SIA-306 and SIB-307 in SDC lines).
      • Inaccurate if SDC flow > 5000 gpm
    • Power Supplies
      • NNN-D11 (A) / NNN-D12 (B)
      • PNA-D25/PNB-D26 powers the flow compensation
    • Level deviations require UOM permission prior to continuing drain down
    • Loss of MCR indication: 15 minute local monitoring / recording



What can cause the RWLIS local sightglass to become inaccurate?

What about the FTs?


When SDC is running in that loop(due to venturi effect on the sightglass)

When SDC flow is > 5000gpm(unable to compenate for this much flow)


State the SDC limitations that will prevent vortexing associated with the following levels:

  • < 107’ 
  • < 104’ 
  • < 103’ 1” 
  • > 107’ 
  • 103’ 1” to 102’ 
  • 102’ to 101’ 6” 
  • 101’ 6” 
  • when ≤ 103’ 8”
  • if ≤ 101’ 4”


SDC Limitations (prevent vortexing):

  • < 107’ Limited to 1 SDC pump per loop (both trains can be operated)
  • < 104’ Limited to 1 SDC pump and loop.
  • < 103’ 1” Cannot use CSP for SDC in mid-loop
  • > 107’ SDC flow 3780 – 5000 gpm
  • 103’ 1” to 102’ SDC flow rate between 3780 - 4600 gpm
  • 102’ to 101’ 6” SDC flow rate between 3780 - 4150 gpm
    • 3780 gpm is Tech Spec Minimum flow
    • < 4000 gpm may allow RCS heat-up when DHR is high
    • Low flow alarm (3615 gpm 1 pump / 7400 gpm 2 pumps in a train)
  • 101’ 6” Minimum level for LPSI pump suction
  • SI piping vented every 2 hours when ≤ 103’ 8”
  • Loss of SDC, refer to Lower Mode FR (40EP-9EO11)
    • FR directs stopping SDC pumps if ≤ 101’ 4”



State the drain rates associated with the condition of fuel in the vessel.

Drain Rates (fuel in the vessel):

  • 40 gpm: level > 111’ and only using the Vessel Head Vent orifice
    • Small head vent path will lead to difference in indicated vs actual vessel level (pulls vacuum on head)
  • 135 gpm: Grayloc hubs open
    • Creates larger head vent path. Actual vs indicated level should track better


What is the precaution associated with drain paths during operations that lower RCS inventory?

Drain Paths:

  • Only one drain path at a time can be used to reduce RCS level.
  • Letdown to RWT or HUT, alternate drain path using SDC line to the RWT


State the purpose and limitations associated with gravity makeup source.

  • Gravity Make-up source available
    • Available during loss of power
    • Does not prevent boiling
    • Makes up for boil off
    • RWT level high enough to ensure head will push water into the RCS. Surge Line flooding can allow head to pressurize.


State the purpose and limitations associated with a pumped/powered RCS makeup source.

  • Pumped make-up source available
    • HPSI is 1st source
    • Will not maintain subcooling if decay heat is > 16 MW (within 87 hours of shutdown)
    • HPSI to cold leg path required if cold legs intact (throttling required to prevent runout)
    • HPSI to hot leg injection is preferred if RCP is disassembled with pump bowl open OR any cold leg vent path open


What are the other requirements associated with RCS makeup sources when RCS inventory has beed reduced associated with:

vent path

gravity and hpsi injection.

  • Hot leg vent path established (PZR manway removed)
  • Gravity makeup and HPSI injection must be on opposite equipment trains



State the consequences associated with the surge line configuration at PVGS during a RCS boiling event. 

How is this prevented?

  • Should boiling occur the possibility exists of escaping steam velocity in the 12" surge line to not allow water to drain back down from the PZR into the RCS.
  • Impacts actual vessel level and RWLIS system indication due to increased RCS pressure.
  • Minimum level requirements in the RWT such that water elevation will provide sufficient head to overcome internal RCS pressure due to surge line flooding.


What must be done if RCS boiling does occur during a condition where gravity makeup is being used?


  • If RVLMS is available and level is below the hot leg, the strategy is to maintain level below the top of the hot leg to provide a vent path to the PZR Manway and prevent any pressure buildup in the RCS.
  • If RVLMS is unavailable or level is above the hot leg, SDC Gravity Feed is initiated at a preset level and controlled to conserve RWT inventory, boiling will occur and pressure will build up in the RCS, the RWT will burp into the RCS as the pressure pushes the water level below the hot leg.


What is considered bulk RCS temperature and how is it indicated?

Bulk Temperature

  • Actual temperature in the core
  • Indicated at the CETs with no RCS flow
  • SDC HX inlet temperature with SDC flow


What conditions will affect the amount of decay heat present in the RCS after shutdown?

  • Generated from beta/gamma decay of fission products in the core.
  • DHR is dependent upon the power level that the core operated at and the length of time at power.
  • DHR is highest immediately following shutdown as decay of both long and short lived fission products is occurring.
  • DHR drops quickly in the first 20 days following shutdown as the short lived fission products decay away. As the short lived fission products decay away, DHR becomes relatively constant due to the remaining long lived fission products.



What parameters are calculated from the DHR curves in 40OP-9ZZ16?

  • DHR curves used to estimate DHR, core heat up rate, time to boil, time to core uncovery in mid-loop and make-up flow rates for a loss of SDC



What are the affected unit SM duties during reduced inventory operations?


  • Authorize opening the Containment Equipment Hatch when level is > 111’.
  • Authorize opening Containment penetrations.
  • Determine the need to establish a Closed Containment condition.
  • Review WOs and determine if the work has the potential for inducing a perturbation on RCS level.
  • Determine which WOs identified as having a potential to perturb the RCS require rescheduling.
  • Notify Unit 1 SM and Outage Management when entering/exiting Reduced Inventory.
    • U1 SM notifies ECC
  • Notify Outage Management prior to entry into Reduced Inventory and after exiting Reduced Inventory.



Who is responsible for implementing containment closure in the event it is required?

The SM will ensure the responsible personnel identified on the open containment penetration log is notified if conditions are required?


Whose permission is required to open the equipment hatch when level is <= 111'?


The Unit OPS Manager


What are the Mid-loop OPS Coordinator duties during reduced inventory?

  • Qualified STA (may be the duty STA)
  • MLOC duties can be delegated to other STAs. Cannot delegate RCS level monitoring.
  • Monitors level during mid-loop
  • Evaluates work that could affect level, concurs with SM on mid-loop related decisions.
  • Notifies responsible individuals for penetration closure if required.


What is the definition of Closed Containment and how long must a penetration be capable of being closed?

  • Closed Containment: Provides at least one barrier to the release of radioactive material to outside CTMT. Reasonably expected to remain in place following a core melt accident.
  • Open penetrations, including Equipment Hatch, must be capable of being closed within time to core boil or 60 minutes whichever is more limiting.


How are penetrations from containment to the atmosphere isolated?

  • Penetrations from CTMT to outside atmosphere shall be closed by a valve or blind flange.
    • Closure by a valve or blind flange used for CTMT isolation during power operation meets this specification.
    • Closure by other valves or blind flanges may be used if they are similar in capability to those provided for CTMT isolation. May be constructed of standard materials and may be justified on the basis of either normal analysis methods or reasonable engineering judgment.


How long does it take to make the equipment hatch effectively closed?

  • Hatch takes ~ 30 minutes to close with 4 bolts (No gaps in sealing surface)
  • Hatch is closed and one door in each airlock must be capable of being closed with a door operator stationed.


What must be met to open the equipment hatch in reduced inventory?

  • If hatch must be opened in Reduced Inventory:
    • UOM permission required
    • Time open is minimized
    • Time to boil will be > 30 minutes
    • Tools/equipment staged for closing the hatch
    • Personnel will be stationed in CTMT to close the hatch


What are the requirements associated with entering Reduced Inventory condition?

Reduced Inventory Requirements:

  • MLOC stationed
  • Aux Bldg SRO stationed to evaluate all work prior to entering the Aux Bldg
  • Two CETs available
  • Two level monitors functional
  • Hot leg vent path (PZR manway) established prior to opening a cold leg vent
    • Prevents uncovering the core due solely to RCS pressurization during a loss of SDC
  • SWYD protected / work stopped


Whose permission is required to permit category C work during reduced inventory?

  • MOLC/SM approve Category C work


State the differences associated with 40OP-9ZZ23 Outage GOP and 40OP-9ZZ24 Short Notice Outage

40OP-9ZZ23 Outage GOP Purpose:

  • Moves the plant from Mode 3 to Mode 6 for a refueling outage and back to Mode 3.
  • Performs RCS activated corrosion product removal.
  • Establishes conditions to support refueling and maintenance.


40OP-9ZZ24 Short Notice Outage Purpose:

  • Moves the plant from Mode 3 to Mode 5 for short notice outage work (SNOW) and back to Mode 3.
  • Performs RCS activated corrosion product removal.
  • Establishes conditions to support Mode 5 maintenance.


State several of the PZR cooldown requirements for the outage GOPs


  • LPZR instruments are verified accurate
  • Maintain RCS and PZR CDR Limits.
  • Auxiliary Spray Valves may be left continuously open during PZR cooldown.
  • Cycle PZR heaters to maintain PZR CDR within LCO limits. (200°F/hour)
  • Secure RCP Seal Injection
  • Monitor for signs of RCS voiding.
  • Ensure RWT level and Boron concentration is adequate
    • 30,000 gallons is required to cool down and fill the PZR and recommended Boron is >4270 ppm.
  • RCS Boron is > 3000 ppm
  • When the ΔT between RCS Thot and the PZR has been < 200°F for at least 1 hour, raise LPZR to ~ 95% by ↓ letdown flow.
  • ↑ PZR nitrogen overpressure to 100 psia.
  • After 30 minutes, lower LPZR to 25% by ↑ letdown flow (preferred method).
    • Letdown used for purification (alternate is using SDC to RWT)
  • Repeat the above steps as needed to cooldown the PZR.
  • When the PZR is at the desired temperature, close the auxiliary spray valve(s).


State the major steps associated with venting the PZR to Containment.

Venting the PZR to CTMT

  • RCS venting method will pull a slight vacuum on the PZR before the PZR is vented to CTMT. (Radioactive gasses)
  • Close Aux Spray valves.
  • Adjust charging line backpressure to 135 psid
  • Blank flange is installed downstream of the PZR/RV Hd Vent to CTMT Vlv (RCA- HV-106).
  • Nitrogen rig is isolated from the PZR.
  • Align the PZR vent valves to the RDT.
  • RDT is aligned to vent to the Waste Gas Header.
  • Raise and maintain LPZR at ~ 50%.
  • If RDT pressure approaches 10 psig stop/slow the fill and depressurize the RDT.
  • When PZR pressure is < 25 psia, then stop venting to the RDT.
  • Open RCN-V203 (aligns vent path to the CTMT sump)
  • ↓ LPZR until PZR pressure indicates less than zero in the MCR.
  • Open the PZR/RV Hd Vent to CTMT Vlv (RCA-HV-106).
  • Air should be drawn into the PZR.


State the major steps associated with drawing a bubble in the PZR.

Drawing a PZR Bubble

  • Open PZR vent valves, aligned to RDT
  • Start raising level with a target of 90% to 95%. (Verify PZR LIs within 3% when on-scale)
  • Start a PZR cooling fan.
  • Energize PZR Heaters
  • When at 90% to 95% level, close PZR vent valves.
  • When PPZR > 25 psia, vent non-condensable gases to the RDT. Stop venting after 15 to 20 minutes.
  • Begin lowering LPZR to ~ 35 - 40% using letdown backpressure valves
  • Operate Heaters to ↑ PPZR to 100 - 190 psia, and vent the PZR every 12 hours.
  • When LPZR is 35 - 40% (LI-103), place the “Normally Running” and “Standby” Charging Pumps in service.
  • Balance Charging and Letdown flows.
  • Maintain RCS pressure 100 psia to 190 psia and 50% to 54% level.