Reduced Inventory / Mode 6 / Outage

Question 1

State the purposes of 40OP-9ZZ16 RCS Drain Operations to include minimum allowed level.

Answer 1

• Places the RCS in a drained condition. Between 10% L_PZR [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.

Question 2

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”

Answer 2

• 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 (L_PZR 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)

Question 3

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

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

Answer 3

• LT-110X/110Y (Hot cal L_PZR) and LT-103 (Cold cal L_PZR)
  
  • 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

Question 4

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.

Answer 4

• 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

Question 5

What can cause the RWLIS local sightglass to become inaccurate?

What about the FTs?

Answer 5

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)

Question 6

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”

Answer 6

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”

Question 7

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

Answer 7

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

Question 8

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

Answer 8

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

Question 9

State the purpose and limitations associated with gravity makeup source.

Answer 9

• 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.

Question 10

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

Answer 10

• Pumped make-up source available
  
  • HPSI is 1^st 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

Question 11

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

vent path

gravity and hpsi injection.

Answer 11

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

Question 12

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

How is this prevented?

Answer 12

• 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.

Question 13

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

Answer 13

• 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.

Question 14

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

Answer 14

Bulk Temperature

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

Question 15

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

Answer 15

• 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.

Question 16

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

Answer 16

• 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

Question 17

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

Answer 17

• 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.

Question 18

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

Answer 18

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

Question 19

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

Answer 19

The Unit OPS Manager

Question 20

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

Answer 20

• 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.

Question 21

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

Answer 21

• 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.

Question 22

How are penetrations from containment to the atmosphere isolated?

Answer 22

• 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.

Question 23

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

Answer 23

• 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.

Question 24

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

Answer 24

• 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

Question 25

What are the requirements associated with entering Reduced Inventory condition?

Answer 25

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

Question 26

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

Answer 26

• MOLC/SM approve Category C work

Question 27

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

Answer 27

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.

Question 28

State several of the PZR cooldown requirements for the outage GOPs

Answer 28

• L_PZR 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 L_PZR to ~ 95% by ↓ letdown flow.
• ↑ PZR nitrogen overpressure to 100 psia.
• After 30 minutes, lower L_PZR 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).

Question 29

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

Answer 29

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 L_PZR 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)
• ↓ L_PZR 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.

Question 30

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

Answer 30

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 P_PZR > 25 psia, vent non-condensable gases to the RDT. Stop venting after 15 to 20 minutes.
• Begin lowering L_PZR to ~ 35 - 40% using letdown backpressure valves
• Operate Heaters to ↑ P_PZR to 100 - 190 psia, and vent the PZR every 12 hours.
• When L_PZR 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.

Question 31

When is the RCP shaft blocking device required to be installed?

Answer 31

• RCP shaft blocking device is required to be installed when ALL of the following conditions exist to prevent damage to RCP seals or loss of RCS inventory:
  
  • Any RCP seal replacement is in progress
  • Any RCP is on the stop seal
  • A start is required of a Safety Injection Pump or Charging Pump to add RCS inventory

Question 32

When should RCP seal inj be inservice?

Answer 32

• Seal injection should be supplied when:
  
  • RCS level is above top of the hot legs
  • RCS ≥ 195°F and > 215 psia

Question 33

State the required Seal Inj status and bleed off valve position for the following conditions if the RCS seal is intact and the level has been <104’.

• < 102’7”
• 102’7” to 111’ when RCS level was raised
• 102’7” to 111’ when RCS level was lowered
• >111’

Answer 33

• If any RCS is intact (NOT on stop seal) AND level has been < 104’:

RCS level

Evolution

Seal Injection

Bleed-off Valve

≤ 102’ 7”

↑ or ↓ level

May be OOS

Open or closed

Between 102’ 7” to 111’

↑ level

Required to be in-service

Open or closed

Between 102’ 7” to 111’

↓ level

May be OOS

Closed

> 111’

↑ or ↓ level

May be OOS

Closed

Question 34

What is required with regard to chemistry control when < 200 F RCS temperature?

Answer 34

• ≤ 200°F: perform forced oxygenation (inject hydrogen peroxide)
  
  • Target temp is 150-180°F
  • Starts a crud burst
  • Raising rad levels in the plant (peaks in ~ 2 hours)
  • Maximize purification

Question 35

What is the required H2 concentration prior to stopping RCPs?

What is required if this is not met?

Why?

Answer 35

• Total gas ≤ 20 cc/kg or shiftly SDC venting prior to stopping RCPs.
  
  • Ensures SGs remain available for DHR (U-tubes not voided)
  • Prevents gasses from coming out of solution during de-pressurization

Question 36

What must be established prior to a hot leg vent path being opened?

Why?

Answer 36

• Before opening a path from an RCS cold leg to CTMT of > 1 in², a Hot Leg vent path must be established.
• Hot leg vent path (PZR manway) is large enough to prevent uncovering the core due to pressurization of the RCS.

Question 37

What is considered a core alteration in 40OP-9zz23?

Answer 37

• Movement or manipulation of any fuel, sources, or reactivity control components [excluding CEAs withdrawn into the UGS], within the reactor vessel with the vessel head removed and fuel in the vessel.

Question 38

Can suspension of core alterations stop the in progress movement of the following evolutions?

• CEA Coupling/Uncoupling
• Fuel/CEA/Source Movement (Does NOT apply to the last F/A removed or the first F/A inserted into the vessel)
• Fuel Realignment after Fuel Position Verification
• UGS Lift Rig CEA Support Plate Raise/Lower with CEAs Latched
• CEA Drag Test

Answer 38

NO

Question 39

What is considered a core alteration?

Answer 39

• Movement or manipulation of fuel, sources or reactivity control components in the Vessel while fuel is in the Vessel
• Any movement or manipulation of any fuel (whether contained in an intact assembly or as an individual rod) in the Reactor Vessel constitutes a core alteration. NRC approval of a Tech Spec change is required to allow re-caging of a F/A in the Vessel without instituting all core alteration Tech Spec requirements

Question 40

How are stopping of core alterations considered?

Answer 40

Cessation of Core Alteration

• Brief admin holds of core alts are not formally considered Suspension of Core Alterations unless declared so by SM or RSRO.
• Core Alterations are considered to be administratively suspended when the movement or manipulation of any fuel, sources or reactivity control component within the Vessel has ceased, and the RSRO has communicated the cessation of core alterations to the MCR.
• As long as no actual movement of any fuel, sources or reactivity control component within the Vessel is occurring, communications may be terminated as long as a communications check is performed prior to resuming core alterations. During these intervals, the individuals associated with the core alteration can be contacted using the Plant Page System.