Text

Palo Verde, Units 1, 2, and 3 - Final Integrated Plan in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049)
	ML15364A034
Person / Time
Site:	Palo Verde
Issue date:	12/24/2015
From:	Lacal M L; Arizona Public Service Co
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	102-07159-MLL/TNW, EA-12-049
	Download: ML15364A034 (103)
	v • d • e

EA-12-049 QapsMaria L. LacalVice President, NuclearRegulatory

& Oversight Palo VerdeNuclear Generating StationP.O. Box 52034Phoenix, AZ 85072Mail Station 7605Tel 623.393.6491 102-07159

-M LL/TN WDecember 24, 2015U.S. Nuclear Regulatory Commission ATI'N: Document Control Desk11555 Rockville PikeRockville, MD 20852

References:

1. NRC Order Number EA-12-049, Order Modifying Licenses withRegard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events, dated March 12, 20122. NRC Interim Staff Guidance JLD-ISG-2012-01, Compliance withOrder EA-12-049, Order Modifying Licenses with Regard toRequirements for Mitigation Strategies for Beyond-Design-Basis External Events, Revision 0, dated August 29, 20123. NEI 12-06, Diverse and Flexible Coping Strategies (FLEX)Implementation Guide, Revision 0, dated August 21, 20124. APS Letter 102-06670, APS Overall Integrated Plan in Response toMarch 12, 2012 Commission Order Modifying Licenses with Regardto Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049),

dated February 28,2013

Dear Sirs:

Subject:

Palo Verde Nuclear Generating Station (PVNGS)Units 1, 2, and 3Docket Nos. STN 50-528, 50-529, and 50-530APS Final Integrated Plan in Response to March 12, 2012Commission Order Modifying Licenses with Regard toRequirements for Mitigation Strategies for Beyond-Design-Basis External Events (order Number EA-12-049)

On March 12, 2012, the Nuclear Regulatory Commission (NRC) issued an order(Reference

1) to Arizona Public Service Company (APS). Reference 1 wasimmediately effective and directs APS to develop, implement, and maintain guidanceand strategies to maintain or restore core cooling, containment, and spent fuel poolcooling capabilities in.the event of a beyond-design-basis external event. Specificrequirements are outlined in Attachment 2 of Reference 1.Reference 1 required submission of an overall integrated plan (OIP) by February 28,2013. The NRC Interim Staff Guidance (ISG) (Reference

2) was issued August 29,2012 which endorses industry guidance document NEI 12-06, Revision 0 (Reference

3) with clarifications and exceptions.

APS provided the OIP (Reference

4) pursuant toSection IV, Condition C.1, of Reference 1.A member of the STARS (Strategic Teaming and Resource Sharing)

AllianceCallaway

Diablo Canyon

Palo Verde

Wolf Creek 102-07159-MLL/TNW ATTFN: Document Control DeskU.S. Nuclear Regulatory Commission APS Final Integrated Plan in Response to March 12, 2012 Commission OrderModifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049)

Page 2The NRC staff subsequently requested that, within 60 days of the date for the finalunit to achieve compliance at their plant, licensees submit a Final Integrated Plan(FIP), reflecting the strategies for their plants on that date. This letter transmits theFIP for PVNGS Units 1, 2, and 3. The information in the FIP supersedes theinformation provided in the OIP.The NRC also requested that, within 60 days of the compliance date for the final unitat their plant, licensees submit responses tO the NRC Open Items, Confirmatory Items, and Audit Items identified by the staff regarding the mitigation strategies implemented at their sites. The APS response for the Palo Verde Nuclear Generating Station (PVNGS) site was submitted by letter number 102-07157, dated December17, 2015.No commitments are being made to the NRC by this letter.Should you have any questions concerning the content of this letter, please contactThomas Weber, Department Leader, Regulatory

Affairs, at (623) 393-5764.

I declare under penalty of perjury that the foregoing is true and correct.Executed on December 24, 2015* (Date)Sincerely, MLL/TNW/PJH/af

Enclosure:

Final Integrated Plan Palo Verde Nuclear Generating Station (PVNGS)Units 1, 2, and 3cc: M. L. Dapas NRC Region IV Regional Administrator M. M. Watford NRC NRR Project ManagerL. J. KIos NRC NRR Project ManagerC. A. Peabody NRC Senior Resident Inspector J. P. Boska NRC NRR/JLD/JOMB Project Manager ENCLOSURE FINAL INTEGRATED PLANPALO VERDE NUCLEAR GENERATING STATIONUNITS 1, 2 AND 3 Final Integrated PlanNRC Order EA-12-049, Palo Verde Nuclear Generating StationUnits 1, 2 and 3FINALINTEGRATED PLANPALO VERDE NUCLEAR GENERATING STATIONUNITS 1, 2AND 3Page 1 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2 and 3Table of ContentsTable of Contents

.......................

.....................................................

2List of Tables ...........................

.......

...............................................

4List of Figures .....................................

4Acronyms

.......................................................................................

6Executive Summary.........................................................................

101. Background

....................

......................

................................

122. General Integrated Plan Elements

................................................

132.1. Assumptions......................14 2.2. Analytical Methods and Computer Codes used in Key Analyses

........

152.3. Procedural controls...............

....... 203. Strategies.....................................................

.... ....................

204. Reactor Core Cooling and Heat Removal Strategy.............................

214.1. Reactor Coolant System at power ..........................................

214.2. Reactor Coolant System at Lower Modes..................................

254.3. Systems, Structures, Components

.. ......................................

274.4. FLEX Modifications in Support of Phases 2 and 3 ........................

314.5. Key Reactor Parameters..................38

5. Spent Fuel Pool (SFP) Cooling/Inventory Strategy..............................

395.1. Spent Fuel Pool Cooling Strategy, ELAP During Power Operation

.....405.2. Loss of Power with a Full Core Off-Load (at least 100 hours0.00116 days 0.0278 hours 1.653439e-4 weeks 3.805e-5 months intorefueling)

......................................................................

415.3. Systems, Structures, Components

...................................

.......425.4. SFP Cooling Modifications

...................................................

425.5. Key Spent Fuel Pool Parameters...........................................

436. Containment Integrity Strategy

.....................................................

436.1. Containment Integrity at Power.............................................

436.2. Containment Integrity during Modes 5 and 6 (fuel in reactor vessel and inthe containment with no fuel movement)...................................

436.3. Systems, Structures, Components

.........................................

446.4. Key Containment Parameters

..............................................

446.5. FLEX Modifications

.....................................

............

.........

457. Characterization of External Hazards ..........................................

...457.1. Seismic ............

....................

457.2. High Temperatures

.... ................

...467.3. Not Applicable External events ...............................................

468. Protection of FLEX Equipment

.....................................

... .............

478.1. FLEX Emergency Equipment Storage Facility and Deployment..........

478.2. FLEX Deployment Pads..............................

48Page 2 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2 and 39. Planned Deployment of FLEX Equipment.,

...............

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489.1. Deployment Routes...............

.............

...............................

489.2. Accessibility

...................................

... .............................

489.3. On-Site Fuel Storage Tanks and Qualifications............................

4910. Deployment of Major FLEX Equipment and Strategies

........................

4910.1. Reactor Core Cooling and Heat Removal Equipment Deployment andAssociated Water Inventory Sources .......................................

4910.2. RCS Injection Skid Deployment and Associated Water Inventory Sources5010.3. SFP Makeup Pump Deployment and Associated Water Inventory Sources .........................................

....:..........................

5110.4. FLEX 480 VAC Electrical Generator Deployment.........................

5110.5. Defense-in-Depth 4.16 kV 4 MW Electrical Generator Deployment.....52 10.6. Fueling of Equipment........................................................

5211. Offsite 5311.1. National SAFER Response Center.........................................

5312. Equipment List...........,............................................................

5313. Habitability and Operations

..........................................

,...............54 13.1. Equipment Operating Conditions...,.........................................

5413.2. Personnel Habitability.........................................................

5413.3. Lighting

...............

.........

..............................................

5513.4. Communications

..........

..................................................

5513.5. Additional Water Sources....................................................

5613.6. Staffing

.. .....................................................................

5614. Sequence of Events .......

5615. Programmatic Elements

.... .... ..................................................

5715.1. Overall Program Document

..........

.......................................

5715.2. Procedural Guidance

........................................................

5815.3. Organizational responsibilities

..............................................

5915.4. Training

........,...............

...............................................

6015.5. Equipment Maintenance and Testing .... ..............................

i......61 References

.................................................................

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62Regulatory.............

.....................

.......................

i.....................

62APS Documents...............................

................

i........................

65External to APS........................................................................

67Tables and Figures......;...........................:............................................69 Page 3 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2 and 3List of TablesTable 1: 480 VAC FLEX Generators Essential Load List..............................

69Table 2: PVNGS FLEX Phase 2 Equipment Providing Safety Function(s)..........

70Table 3: PVNGS Other FLEX Equipment Available on Site ...........................

71Table 4: PVNGS FLEX Miscellaneous EquipmentlCommodities

.....................

72Table 5: Sequence of Events Timeline, Modes I -4....................................

73List of FiguresFigure 1 : FLEX Primary and Alternate RCS Injection Schematic for Modes I -4.. 77Figure 2: FLEX Primary RCS Injection Tie-in Simplified Piping......................

78Figure 3: FLEX Alternate RCS Injection Tie-in Simplified Piping ....................

79Figure 4: FLEX RCS Makeup Schematic for Modes 5 and 6 ..........................

80Figure 5: FLEX Primary and Alternate Secondary Makeup Schematic

.............

81Figure 6: FLEX Secondary Plant Makeup Simplified Piping ..........................

82Figure 7: FLEX 480 VAC Physical Layout ...............................................

83Figure 8: FLEX 480 VAC Electrical Schematic

..........................................

84Figure 9: FLEX Motor Driven RCS Injection Physical Cable Layout (GroundElevation)

.........................................................................

85Figure 10: FLEX Electrical Modifications Schematic

..................................

86Figure 11: Defense-in-Depth 4.16 kV AC Physical Layout ............................

87Figure 12: Defense-in-Depth 4.16 kV AC ElectricaliSchematic.......................

88Figure 13: FLEX Primary and Alternate SFP Makeup Schematic for All Modes(FLEX SFP Pump Discharge)

..................................................

89Figure 14: FLEX Primary and Alternate SFP Makeup Schematic (FLEX SFP PumpSuction)....

.......................................................................

90Figure 15: FLEX Primary and Alternate SFP Makeup Simplified Piping.............

91Page 4 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 3Figure 16: Photograph of Primary and Alternate SFP Makeup Piping and Nozzleswithin the Fuel Building.......................................................

92Figure 17: FLEX Containment Vent Path Configuration in Lower Modes ..........

93Figure 18: FLEX EESF and Vicinity

..........................

..............................

94Figure 19: FLEX Deployment Locations (Seismic Pads and Tie-downs for Pumpsand Generators)..............

..... ...... .......................................

95Figure 20: FLEX Deployment Routes ..........................................

i...........96 Figure 21: FLEX Primary and Alternate SG Makeup Pump Deployment Arrangement

...................................................................

97Figure 22: FLEX Primary and Alternate SFP Makeup Pump and Primary RCSInjection Pump Deployment Arrangements

....... .......................

98Figure 23: FLEX Alternate RCS Injection Pump Deployment Arrangement atGround Level in the Auxiliary Building......................................

99.Figure 24: FLEX Deployment Arrangement for 480 V, 800 kW Generators andDefense-In-Depth 4.16 kV, 4 MW (Total) Generators....................

100Page 5 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 3AcronymsAC.............................................................

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Alternating CurrentADAMS ........................

Agencywide Documents Access and Management SystemADV...................................................................

Atmospheric Dump ValveAFAS ...................................................

Auxiliary Feedwater Actuation SignalAFT .............

....................................................

Applied Flow Technology AFW ........................................................................

Auxiliary Feedwater AHU ...........................................................................

Air Handling UnitAPS .........................................................

Arizona Public Service CompanyAOP..........................................................

Abnormal Operating Procedures ASCE ............

American Society of Civil Engineers ASHRAE....American Society of Heating, Refrigerating and Air-Conditioning Engineers ASME............................................

American Society of Mechanical Engineers ASTM... ........................................

..American Society for Testing and Materials BDB....................................................

Beyond-Design-Basis BDBEE .. .............................................

Beyond-Design-Basis External EventsBtu ...........................................................................

British thermal unitCE.....................................................................

Combustion Engineering CET..................................................................

Core Exit Thermocouples CENTS...............................

Combustion Engineering Nuclear Transient Simulator CRE.....................................................................

Control Room EnvelopeCST .................................................................

Condensate Storage TankCVCS .................................................

Chemical and Volume Control SystemDG .............................................................................

DieselIGenerator DC.............................................

....................................

Direct CurrentEAL ..............

....................................................

Emergency Action LevelEC .........................................................................

Engineering ChangeECCS .........................

...............................

Emergency Core Cooling SystemEDMG ...............................................

Extreme Damage Mitigation Guidelines EESF............................

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Emergency Equipment Storage FacilityELAP ......................

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Extended Loss of Alternating Current PowerEOF....................................

........................

Emergency Operations FacilityPage 6 of 100' Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 3EOP..........................

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.Emergency Operating Procedure EPRi ...................................

Electric Power Research Institute ERO......................................................

Emergency Response Organization ESF ..............................

i..................................

Engineered Safety FeatureETAP ..................................................

Electrical Transient Analyzer ProgramF ..........................

............................................................

Fahrenheit FSG ... .................................

... ...............

FLEX Support Guidelines FLEX....................-...............................

Diverse and Flexible Coping Strategies FMEA .........................................................

Failure Modes Effects Analysisg p m .. ........................................................................

G a llo n s p e r M in uteGOTHIC ..................

Generation of Thermal-Hydraulic Information for Containments HCLPF........................................

High Confidence of Low Probability of FailureHDPE ..........

...............................................

....High Density Polyethylene HELB ..............

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High Energy Line BreakHPSI......................High Pressure Safety Injection HVAC ........

..................

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Heating, Ventilation, and Air Conditioning IEEE.........................................

Institute of Electrical and Electronics Engineers INPO ............................................ Institute of Nuclear Power Operations ISG ........................................................................

Interim Staff GuidanceKeff ....................

K effective, neutron multiplication, used as a measure of criticality safetyKSB..........

...........................................

Klein, Schanzlin

& BeckerLCO..................

...Limiting Condition for Operation LOCA......................

...........................................

Loss of Coolant AccidentLOP ................

...............

...Loss of PowerLPSI........................................

...... Low Pressure Safety Injection LUHS........................................................,

... Loss of the Ultimate Heat SinkMAAP.................Modular Accident Analysis ProgramMCC ...............

...............

Motor Control CenterMS ........................

' .............................................

Microsoft MSSS ..........................................................

Main Steam Support Structure MSSV...;.............................................................

Main Steam Safety ValveNC ..................

.................

Natural Circulation Page 7 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2and 3NEI......................................................................

Nuclear Energy Institute NEMA .........

...;.. ..................

i.........

National Electrical Manufacturers Association NRC .................

].........

US Nuclear Regulatory Commission NSRC ......................................................

National SAFER Response CenterNSSS .......................................

................

,......Nuclear Steam Supply SystemNTTF ...................................

...............................

..Near-Term Task ForceOBE...............................................................

Operating Basis Earthquake alP .... ..................

...............................................

Overall Integrated PlanORIGEN........................................................

Oak Ridge Isotope GENerator PEICo...................:..............................

Pooled Equipment Inventory CompanyPM.......

......................................................

........

Preventative Maintenance PMF ...................

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Probable Maximum FloodPMP. ..... .........

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Probable Maximum Precipitation ppm............................

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"....................................

Parts per Millionpsia ...................

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Pounds per Square Inch Absolutepsig....

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Pounds per Square Inch GaugePVNGS ....................................

....... ...Palo Verde Nuclear Generating StationPWROG .....................................

.:...Pressurized Water Reactor Owners GroupQ1 E .................................................

Quality "Q" Class 1 Electrical Equipment RAI .....................

'.........................

...........

Request for Additional Information RCP......................................................................

Reactor Coolant PumpROS ....................

.,..............................................

Reactor Cooling SystemRHR....................................................................

Residual Heat RemovalRMWT-...................................................

-........

Reactor Makeup Water TankRPM..........

...............

.............................................

Revolutions per MinuteRVLMS..........................................

... Reactor Vessel Level Monitoring SystemRWT ...................................................

.i.......Refueling Water TankSAFER ..................................

Strategic Alliance for FLEX Emergency ResponseSAMG .............................................

Accident Mitigation Guidelines SAT.........................................................

.Systematic Approach to TrainingSBCS ..............

..............................

Steam Dump and Bypass Control SystemSBO ................................................

...........................

Station BlackoutPage 8 of 100 Final Integrated PlanNRC Order EA-1 2-049Palo Verde Nuclear Generating Station.Units 1, 2 and 3SBOG ..............................................................

Station Blackout Generator SER...................................................................

Safety Evaluation ReportSEP ......................................

Fuel PoolSG....................

...............

..........................................

Steam Generator SIT.......................

................

'..................................

Safety Injection TankSS .....................................................

....... .........

.. ......Stainless SteelSSC .....................................................

Structures,

Systems, and Components SSE ..................................................................

Safe Shutdown Earthquake TDAFW .........................................

.......'...Turbine Driven Auxiliary Feedwater UFSAR ......................

..........................

iUpdated Final Safety Analysis ReportUGS .....i..........................*.................................

..... Upper Guide Structure UHS...................................................................

.......Ultimate Heat SinkUSGS........................................................

United States Geological SurveyVAC .................................................................

Volts -Alternating CurrentVDC .............

..... ...................................................

Volts -Direct CurrentVFC .....................

..........................................

Variable Frequency ControlWR ..................................................................................

Wide RangePage 9of 100' Final Integrated Plan Palo Verde Nuclear Generating Station*NRC Order EA-1 2-049 Units 1, 2 and 3Executive SummaryOn March 12, 2012, the Nuclear Regulatory Commission (NRC) issued Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events, to all licensees requiring implementation ofmitigation strategies for beyond-design-basis external events (BDBEE),

as identified inNear-Term Task Force (NTTF) Recommendation 4.2. Order EA-12-049 requiredsubmission of a Final Integrated Plan (FIP) to the NRC after full compliance with thereferenced orders. In order to assist the industry in responding to the NRC order, theNuclear Energy Institute (NEI) developed guidance in report number 12-06, "Diverseand Flexible Coping Strategies (FLEX) Implementation Guide." NRC interim staffguidance (ISG) JLD-ISG-2012-01

endorses, with clarifications, the methodologies described in NEI 12-06.This submittal describes the Palo Verde Nuclear Generating Station (PVNGS) FIP,including key assumptions, implementing strategies, and operator action times forcomplying with the NRC order and implementing FLEX, as described by JLD-ISG-2012-01 and NEI 12-06. The PVNGS FIP contains a description of the general elements ofthe plan, followed by a discussion of the safety functions that are identified in the order,which are core cooling, containment integrity, and spent fuel pool cooling.The NRC order requires that the underlying strategies for coping with BDBEE involve athree-phase approach:*

Phase 1 -Initially cope relying on installed equipment and on-site resources.

Phase 2 -Transition from installed plant equipment to on-site FLEXequipment.

Phase 3 -Obtain additional capability and redundancy from off-site equipment and resources until power, water, and coolant injection systems are restoredor commissioned.

These phases are discussed in the response in terms of how each phase addresses theidentified safety functions.

The first step of the FLEX strategy is establishment of thebaseline coping capability to maintain or restore key plant safety functions under theconditions of an extended loss of alternating current (AC) power (ELAP) and loss ofnormal access to the ultimate heat sink (LU HS). These strategies are independent of aspecific damage state or mechanistic assessment of external events. To meet therequirements of a FIP, the safety functions of core cooling, containment integritY, andspent fuel pool cooling need to be maintained indefinitely under ELAP and LUHSconditions.

Using conservative operator action times and NEI 12-06 guidance,'

ArizonaPublic Service Company (APS) has determined that the long term coping and approachto shutdown cooling is achievable without loss of natural circulation flow. PVNGSprocedures and processes address plant strategies for implementing the FIP.PVNGS coping strategies can be utilized regardless of the initiating external event (asidentified by NEI 12-06). These Strategies were developed to mitigate the impact of anPage 10 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2and 3ELAP and LUHS. However, based on NEI 12-06 screening

guidance, the two externalhazards that are applicable to PVNGS are seismic and extreme heat. Although stationdesign for these external hazards are conservative with ample margin of safety, APShas evaluated the functional threats from each of these hazards and identified FLEXequipment and strategies that are expected to be effective in mitigating these events.Based on this evaluation, strategies that focus on the seismic hazard were selected, since extreme high temperatures for a prolonged duration and extreme drought areslowly progressing meteorological events which can be adequately addressed byexisting plant procedures that will ensure the plant is shutdown, if required, and placedin a safe condition for these situations.

The information within this submittal is prepared solely to support beyond design basesoperational procedures to mitigate the limiting external events applicable to PVNGS. Itprovides a description of the conceptual approach used by APS to implement thePVNGS FIP.This FIP documents the completion of the commitments made in the QIP, andsubsequent communication with the NRC, to comply with NRC Order EA-12-049.

Page 11 of 100 Final, Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 31. Background In 2011, an earthquake-induced tsunami caused beyond-design-basis (BDB).flooding at the Fukushima Dai-ichi Nuclear Power Station in Japan. The floodingcaused the emergency power supplies and electrical distribution systems to beinoperable, resulting in an extended loss of alternating current power (ELAP) in fiveof the six units on the site. The ELAP led to (1) the loss of core cooling, (2) the lossof spent fuel pool cooling capabilities, and (3) the inability to maintain containment integrity.

All direct current (DC) power was lost early in the event on Units 1 & 2 andafter some period of time at the other units. Core damage occurred in three of theunits along with a loss of containment integrity resulting in a release of radioactive material to the surrounding environment.

The US Nuclear Regulatory Commission (NRC) assembled a Near-Term Task Force(NTTF) to advise the Commission on actions the US nuclear industry should take topreclude core damage and a release of radioactive material after a natural disastersuch as that seen at Fukushima.

The NTTF report (Reference

1) contained manyrecommendations to fulfill this charter, including assessing extreme external eventhazards and strengthening station capabilities for responding to BDB externalevents.Based on NTTF Recommendation 4.2, the NRC issued Order EA-12-049 (Reference

2) on March 12, 2012, to implement mitigation strategies forBeyond-Design-Basis External Events (BDBEEs).

The order provided the following requirements for strategies to mitigate BDBEEs:1) Licensees shall develop, implement, and maintain guidance and strategies to maintain or restore core cooling, containment integrity, and spent fuelpool (SEP) cooling capabilities following a BDBEE.2) These strategies must be capable of mitigating a simultaneous loss of allalternating current (AC) power and loss of normal access to the ultimateheat sink (UHS) and have adequate capacity to address challenges to corecooling, containment integrity and SFP cooling capabilities at all units on asite subject to the Order..3) Licensees must provide reasonable protection for the associated equipment from external events. Such protection must demonstrate that there isadequate capacity to address challenges to core cooling, containment integrity, and SFP cooling capabilities at all units on a site subject to theOrder.4) Licensees must be capable of implementing the strategies in all modes.5) Full compliance shall include procedures,

guidance, training, andacquisition, staging or installing of equipment needed for the strategies.

Page 12 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2 and 3The order specifies a three-phase approach for strategies to mitigate BDBEEs:*Phase i -Initially cope relying on installed equipment and on-site resources.

Phase 2 -Transition from installed plant equipment to on-site FLEXequipment.

Phase 3 -Obtain additional capability and redundancy from off-site equipment and resources until power, water, and coolant injection systems are restoredor commissioned.

NRC Order EA-12-049 (Reference

2) required licensees of operating reactors tosubmit an overall integrated plan (OIP), including a description of how compliance with the requirements would be achieved.

The Order also required licensees tocomplete implementation of the requirements no later than two refueling cycles aftersubmittal of the OIP or December 31, 2016, whichever came first.The Nuclear Energy Institute (NEI) developed NEI 12-06 (Reference 75), whichprovides guidelines for nuclear stations to assess extreme external hazards andimplement the mitigation strategies specified in NRC Order EA-12-049 (Reference 2). The NRC issued Interim Staff Guidance JLD-ISG-2012-01 (Reference 3), datedAugust 29, 2012, which endorsed NEI 12-06 (Reference

75) with clarifications on*determining baseline coping capability and equipment quality.

NRC staff reviews ofthe APS efforts to implement the order (Reference

2) are documented in References 5 and 6. References 12, 13 and 14 document the APS conclusion that PVNGS is incompliance with the Order for each of the PVNGS units.2. General Integrated Plan ElementsAPS has evaluated the PVNGS performance for applicable external hazards basedon the requirements of NRC Order EA-12-049 (Reference

2) and the guidanceprovided in Nuclear Energy Institute (NEI) 12-06 (Reference 75). The PVNGSOverall Integrated Plan (OIP) (Reference

9) and subsequent communication provideadditional details.

PVNGS has determined that regardless of the initiating externalevent, the coping strategies address the impact to the station from an ELAP andLUHS. The basis for how the NEI 12-06 guidance was applied for each hazard isdescribed in Section 7 of this report. ,APS has evaluated the functional threats from each of the applicable hazards andidentified equipment and strategies that are expected to be effective in thedeployment of Diverse and Flexible Coping Strategies (FLEX) for these events. TheFLEX portable equipment,

storage, and deployment locations provide appropriate protection from these hazards using station procedures and processes.

Page 13 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2 and 32.1. Assumptions The key assumptions used in the development of the PVNGS Diverse andFlexible Coping Strategies (FLEX) are stated below:1) All stationary AC power sources (onsite and offsite) are lost at the timeof the initiating event (t=0).2) The initiating event is an extreme external event that results in an ELAP,which causes all three (3) reactors at PVNGS to trip.*3) All three (3) reactors (units) are initially operating at full power (seeAssumption 4 below) or two (2) units are at full power with one (1) unit innormal refueling.

4) Prior to the initiating event the reactors (all units or 2 out of 3 units perAssumption 3 above) have been operating at 100 percent of licensedpower (3990 MWth) for at least 100 days and core decay heat issufficient for secondary steam source to drive essential TDAFW toperform its design function.

5) Units are not in any Technical specification, Limiting Condition forOperation (LCO).6) All operating reactors are shutdown and all control rods are inserted atthe time of the initiating event (t=0), per design.7) The reactors and supporting plant equipment are operating within normalranges at the time of the initiating event and function as they weredesigned during FLEX phase 1.8) No independent events (e.g., active security threat, fire, or internalflooding) occur concurrently with the initiating event.9) No fatality or injury of essential personnel occurs as a result of theapplicable hazards.10) No single failure or partial actuation of active or passive SSCs occursduring the initiating event.11) All SSCs are available.*

12) All seismic category 1 essential electrical, mechanical and controlequipment (passive or active) will remain functional per design, exceptas identified in Assumption 1 above.13) All essential DC power sources,

systems, and components will functionas designed.

Page 14 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 314) Sources of water for cooling and makeup that are contained in systemsor structures are robust, with respect to seismic events, and areavailable for use in phases 2 and 3 of FLEX.15) Diesel fuel oil for FLEX equipment is stored in structures that are robust,with respect to seismic events, and is available for use in phases 2 and 3of FLEX.16) The Spent Fuel Pool structures and boundaries are seismically designedwith significant design margin. These SSCs are seismically qualified andwill not fail as a result of a seismic event.17) Where applicable, the requirements of NTTF 9.3, NRC 10 CFR 50.54(f)letter (Reference

4) are implemented and functional.

18) Reactor coolant inventory loss, post event, consists of reactor coolantpump seal leakage at its prescribed leakage recommended by NUMARC87-00 (Reference 76 and Reference 7).19) Extreme Heat Hazard procedural requirements direct all units toshutdown due to the impending event; the ultimate heat sink (UHS) isnot affected by this hazard.20) PVNGS seismically qualified ultimate heat sink (UHS) is not credited forFLEX per the guidance provided in NEI 12-06 (Reference 75). However,the motive force for the UHS is designed for the limiting safe shutdownearthquake (SSE), with margin, and the system and water inventory areavailable during recovery from a FLEX event. Duration of coping atPVNGS is defined as the time period starting with an initiating event(Assumption 2 above) and ending with recovery of the UHS.21) Relatively short duration evolutions during plant shutdown or startup(less than one shift) are not considered within the scope of FLEXstrategies due to the low probability of an event (Reference 75 andReference 18).2.2. Analytical Methods and Computer Codes used in Key AnalysesRCS and Secondary Side Evaluation (Reference 34, NM 1000-A00002)

PVNGS specific NSSS analysis was performed using the Combustion Engineering Nuclear Transient Simulator (CENTS) Nuclear Steam SupplySystem (NSSS) simulation code, Version 11240 (Reference 84), to evaluatethe ELAP transient response for a maximum of 80 hours9.259259e-4 days 0.0222 hours 1.322751e-4 weeks 3.044e-5 months or until the corebecomes uncovered, which is considered to be the precursor for core damage.Page 15 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 3The PVNGS plant specific analysis is consistent with wcAP-1 7601-P(Reference 78).An ELAP is assumed to occur at normal RCS conditions.

The model evaluates a transient instantaneous loss of all AC power at the initiating event. Thisresults in a loss of forced reactor coolant flow, pressurizer

heaters, pressurizer sprays, charging pumps, letdown, flow, high pressure safety injection (HPSI)pumps,' low pressure safety injection (LPSI) pumps, steam dump and bypasscontrol system (SBCS), and electrically supplied feedwater flow. RCS flow ismaintained by Natural Circulation (NC) and Steam Generator (SG) secondary side heat removal via the Main Steam Safety Valves (MSSVs) early in theevent and then manual remote operation of the Atmospheric Dump Valves(ADVs) after one hour.Secondary makeup inventory is supplied by the essential Turbine DrivenAuxiliary Feedwater (TDAFW) pump. The cases analyzed assume that the twoSGs are connected.

Since one ADV per SG is available and is used to cool theplant, the plant operators steam both SGs to maintain approximately equalpressures.

Thus, assuming that the two SGs are connected has little effect onthe progress of the scenarios, and essentially no impact on the final plantconditions.

Additionally, the CENTS site specific evaluations providedreactivity control profiles and time dependent mass and energy input forcontainment analysis.

The CENTS code is benchmarked to CEFLASH-4A (Reference 85); the codebenchmark is accepted by the NRC (Reference

16) and is considered anacceptable code to determine the time of transition to reflux cooling during anELAP event for the Combustion Engineering (CE) designed plants.Decay Heat Evaluations (Reference 35, NMI1000-A00004)

The Oak Ridge Isotope GENerator (ORIGEN-S) computer code (Reference

87) was used for the calculation of decay heat for the core. Both fissionproduct and actinide contributions were considered as well as activation products of the fuel assembly structural materials.

PVNGS specific best estimate decay heat was developed for use in NSSSanalysis using ORIGEN-ARP libraries and the ORIGEN-S code. This analysisuses the plant specific ORIGEN-ARP library inputs generated in SCALE 6.1(Reference 86).The determination of core decay heat was calculated through modeling threefuel assembly regions (once, twice and thrice burned batches) in the core andsumming the decay heat contributions for the various regions.Page 16 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 3Electrical Analysis of AC Power Circuits(Reference 46, N M1000-A000174, Reference 47, NMI1000-A000176, Reference 48, NM1000-A000175, and Reference 49, NM1000-A0001 77)Computer Code ETAP (Reference

88) was used to evaluate essential 480VAC electrical circuits that are powered by two 800 kW generators.

ACanalysis included:

Load flow and motor starting calculation

Short circuit, arc flash hazard & protective device coordination Single-line diagrams and inputs were developed from planned layouts oftemporary cables, modification

packages, and FLEX final delivered generator sets and loose cabling.

These analyses were done in place of designverification testing and provide a high level of confidence that the integrated system is functional.

Electrical Analysis of DC Battery Loads(Reference 50, NM 1000-A000048)

Battery life cycle analyses were performed consistent with the NEI positionpaper endorsed by the NRC (Reference 17). Verified Microsoft (MS) Excelworksheets were used for calculating the battery discharge durations (Reference 91). The battery life cycle analysis considered pre-selected loadsas described in the FLEX Support Guidelines (FSGs) (Reference 68). It wasassumed that the load shed sequence is completed within 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months of theinitiating ELAP event, and an additional load is shed at 16 hours1.851852e-4 days 0.00444 hours 2.645503e-5 weeks 6.088e-6 months (e.g.,Atmospheric Dump Valves -ADVs). Battery life was evaluated until thebatteries were discharged to the minimum voltage, or until the battery reached72 hours, whichever time was shorter.An aging correction factor of 1.25 was used per IEEE 485-2010, whichcorresponds to the IEEE 450-2002 (Reference

92) recommendation for batteryreplacement when capacity drops to 80% of rated capacity.

A temperature factor of 1.30 was used based on an assumed temperature of 40 degrees F inthe battery compartment for the FLEX event.Hydraulic Calculations (Reference 39, NMI000-A00020 and Reference 42, NM1000-A00032)

Computer code AFT-FATHOM (Reference

89) was used to determine fluidsystem hydraulic performance and to validate that the FLEX portable pumpshave adequate NPSH and discharge flow. System analyses (for full power andlower modes) included:

Page 17 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2and 3* Spent Fuel Pool FLEX makeup lineups and suction sources* RCS FLEX makeup lineups and suction sources* Steam Generator FLEX makeup lineups and suction sourcesPiping takeoff diagrams and inputs were developed from planned layout ofhoses, piping runs per modification

packages, and FLEX final delivered dieseland electric motor driven pump skids. These analyses were done in place ofdesign verification testing and provide a high level confidence that theintegrated system is functional.

SFP Seismic Sloshing and Time to Boil Off Evaluation (Reference 36, NMI1000-A00010)

An analytical calculation method was used with MS Excel software to estimatesloshing using the Housner method and TID-7024 (Reference 90). Theamount of water sloshed out of the SFP is dependent on the wave motioninside of the pool. It is assumed that wave motion is parallel to seismic motionin either the x or y-axis. ln~ this two dimensional

analysis, the depth of the pool(and the maximum height of the wave) is in the z-direction and the equations describing the wave travel are in the x or y-direction.

Any secondary and/orreflected waves will be smaller due to inventory and momentum losses.Time to boil was calculated conservatively using water inventory within thepool after a seismic event by using nominal pool elevation (excluding thevolume occupied by the fuel rack), loss due to sloshing, and system/pool linerleakages.

Decay heat used for this analysis was based on NRC BranchTechnical Position APCSB 9-2 (Reference

22) and is discussed in more detailin Section 5 of this report.Containment Evaluation (Reference 44, NM1000-A00042)

A model of the PVNGS containment building was developed using GOTHIC(Reference

83) to evaluate the long term temperature and pressure during anextended loss of AC power event during power and refueling operation.

Wallsand other significant heat sinks were included using appropriate heat transfercoefficients and boundary conditions.

Solar heating was also applied toappropriate surfaces using the American Society of Heating, Refrigerating andAir-Conditioning Engineers (ASHRAE) sol-air method. In addition, energysources were added based upon heat losses from major Nuclear SteamSupply System (NSSS) components and heat loads from main steam andfeedwater system piping in containment were included.

Page 18 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2and 3Input for mass and energy values were provide by CENTS analysis(Reference

34) as describe above (RCS and Secondary Side Evaluation) for25 gpm / Reactor Coolant Pump (RCP) leakage at the start of the event. Forrefueling modes, pool boil off rate mass and energy was calculated based onbest estimate decay heat (per Reference

35) at 48 hours5.555556e-4 days 0.0133 hours 7.936508e-5 weeks 1.8264e-5 months after reactorshutdown.

Essential Turbine Driven Auxiliary Feedwater Pump Compartment Environmental Analysis(Reference 33, NMI1000-A00001)

A GOTHIC (Reference

83) model of the essential TDAFW pump compartment was developed with a three dimensional control volume to ensure that spatialtemperature gradients, especially buoyancy driven differences, wereappropriately captured.

Adjacent areas with the potential for hydraulic communication with the essential TDAFW pump compartment were modeledwith lumped control volumes.Walls and other significant piping heat sinks were modeled with thermalconductors using appropriate heat transfer coefficients and boundaryconditions.

Doors and openings between the essential TDAFW pumpcompartment and other areas were modeled using an appropriate number offlow paths to allow for natural circulation and establish operator action times.Heat sources such as steam supply and exhaust piping, condensate drainlines, and un-insulated components were modeled directly with thermalconductors.

In addition, direct steam release into the compartment wasincluded to account for turbine gland seal and steam trap bypass leakage.Control Room Habitability (Reference 56, 1 3-MS-C045)

A simplified one node model of the control room using GOTHIC (Reference

83) was modeled to predict a 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months room temperature.

Internal and externalwalls, floors, and ceilings were modeled as thermal conductors Usingappropriate heat transfer coefficient and surface conditions.

The doors wereconsidered closed during the entire period; therefore, no mass transfer tookplace. The heat generated by the instrumentation, lighting components, andpersonnel in the Control Room Envelope (CRE) were added and modeled as asingle heat generating component.

The event scenario was based upon the failure of the normal and essential AirHandling Units (AHUs) in the CRE during a loss of all AC power. Consistent with this event sequence, initial room temperatures and thermal conductor temperatures were established based upon the availability of normalventilation prior to the event.Page 19 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2 and 32.3. Procedural Controls1) Initial operator response is the same as existing procedures for a StationBlackout at power (10 CFR 50.63) and Lower Mode Functional duringrefueling (Reference 66 and Reference 70). FLEX Support Guidelines (Reference 68 and Reference

69) are entered within an hour of theinitiating event.2) National SAFER Response Center (NSRC) will start implementation ofthe Palo Verde SAFER ResponSe Plan and by 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months after notification the first NSRC equipment will arrive at the site (Reference 62 andReference 80).3. Strategies.

The objective of the FLEX strategies is to establish a plant long term copingcapability in order to:1) Prevent damage to the fuel in the reactor and the spent fuel pool and2) Maintain containment integrity These strategies address long term station coping capability as a result of abeyond-design-basis external event (BDBEE) that would result in an ELAP.The plant's long term coping capability is attained through the implementation ofpre-determined strategies (FLEX) that are focused on maintaining or restoring keyreactor core, containment, and spent fuel pool safety functions.

The FLEX strategies are not tied to any specific damage state or mechanistic assessment of events.Rather, the strategies are developed to maintain the key plant safety functions based on the evaluation of plant response to the coincident ELAP event. A safetyfunction-based approach provides consistency and allows coordination with existingplant emergency operating procedures (EOP). FLEX strategies are implemented using FLEX Support Guidelines (FSGs). FSGs, EOPs, and Severe AccidentManagement Guidelines (SAMGs),

in conjunction with the NSRC, provide acomprehensive strategy to mitigate a BDBEE.The strategies for coping with the plant conditions that result from an ELAP eventinvolve a three-phase

approach, as described below:* Phase 1 -Initially cope relying on installed equipment and on-site resources.

Phase 2 -Transition from installed plant equipment to on-site FLEXequipment.

Page 20 of 100 .

Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 3* Phase 3 -Obtain additional capability and redundancy from off-site equipment and resources until power, water, and coolant injection systems are restoredor commissioned.

FLEX phase durations, as described above, are for units experiencing an initiating external event at 100% power. Phase duration for other plant modes are discussed in the applicable sections of this, report.BDBEE strategies are provided for specific plant conditions, when steam generators are available (100% power) or when steam generators are decoupled from the RCSand the RCS vent has been established (refer to the relevant sections of this reportfor the specific plant conditions for which the lower modes strategy are applicable).

Discussion herein is focused on plant modes of operation with the highest decayheat in the Reactor Core or the Spent Fuel Pool. Non-limiting plant conditions suchas start-up and Modes 2-4 shutdown sequence are bounded.The above objectives establish strategies capable of mitigating a simultaneous lossof all AC resulting-from a BDBEE by providing adequate capability to maintain orrestore core cooling, containment integrity, and SFP cooling capabilities at all unitson site simultaneously.

Though specific strategies are proceduralized, due to theinability to anticipate all possible scenarios, the strategies are diverse and flexible toencompass a wide range of possible conditions.

These pre-planned strategies weredeveloped to protect the public health and safety. Their impacts to the design andlicensing basis have been evaluated under 10 CFR 50.59, Changes, Tests, andExperiments.

The plant Technical Specifications contain the limiting conditions for normal unitoperations to ensure that design safety features are available to respond to a designbasis accident and direct the required actions to be taken When the limitingconditions are not met. The result of the BDBEE may place the plant in a condition where it cannot comply with certain Technical Specifications and/or with its SecurityPlan, and, as such, may warrant invocation of 10 CFR 50.54(x),

Conditions ofLicenses and/or 10 CFR 73.55(p),

Suspension of Security Measures.

This position isconsistent with the Task Interface Agreement (TIA) 2004-04 (Reference 15).4. Reactor Core Cooling and Heat Removal Strategy4.1. Reactor Coolant System at powerThe FLEX strategy selected to mitigate an event from 100% power, viaborated makeup and Residual (decay) Heat Removal (RHR) from the PVNGSCombustion Engineering (CE) System 80 NSSS, is to establish naturalcirculation in the RCS using symmetric steam generator cool-down.

This isaccomplished via release of steam from the two Steam Generators and two ofthe four Atmospheric Dump Valves (ADVs), one on each steam generator.

Page 21 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-0.49 Units 1, 2and 3Long term performance of secondary cooling is assured by selection of aconservative operating point for the essential Turbine Driven Auxiliary FeedWater (TDAFW) and maintaining the primary system above the requiredpressure and temperature by controlling the secondary steaming rate.The RCS reactivity and inventory control is achieved initially by discharge ofthe Safety Injection Tanks (SITs) as a result of RCS depressurization.

WhenSITs are emptied, the FLEX portable high pressure RCS injection pump willprovide borated makeup from the Refueling Water Tank (RWT). RCS borationand long term mixing is achieved using a FLEX strategy consistent with theaccepted methods as documented in NRC Acceptance of Boration Strategies (Reference 27).The RHR function is achieved by the essential TDAFW pump. The source ofwater for the essential TDAFW system is the Condensate Storage Tank (CST)*and Reactor Makeup Water Tank (RMWT).Phase 1 StrategyAt the time of the BDBEE which results in an ELAP, reactors and supporting systems are operating normally and within Technical Specifications with noLCOs invoked.

An initiating event results in an ELAP and reactor trip.Automatic plant systems which do not rely on AC power are actuated asdesigned, with the exception of the Emergency Diesel Generators (EDG). Asshown in Table 5, Sequence of Events Timeilne, Modes I -4, operators willenter existing PVNGS emergency and/or abnormal operating procedures (Reference 66 and Reference 67). These procedures will direct the operators to proceed with predetermined actions.

These actions include, but are notlimited to, confirming control rods are inserted, containment is isolated, and theessential Turbine Driven Auxiliary Feedwater (TDAFW) Pump is actuated andoperational.

These procedures will also direct operator action to confirm isolation of anyreactor coolant system (RCS) controlled leakage paths. The Blackoutprocedure (Reference

66) provides direction to dispatch an operator tomanually start the station blackout generators (S BOGs). The FSG will beentered when an SBOG is confirmed to be unavailable and it is confirmed thatoffsite power cannot be restored, by either communication with the loaddispatcher or visual verification of physical damage to site infrastructure.

Oncethe FSG procedure is entered operators will:*Initiate an RCS symmetric cool-down at 70 degrees F/hr to a stand-byRCS temperature and pressure that would support performance of theessential TDAFW pump. TDAFW and ADV controls are available in thecontrol room for remote operation.

The RCS will reach target long termpressure and temperature approximately 3.5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months after the start of cool-down.Page 22 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2 and 3* Perform area walk-downs to limit water inventory loss and open theessential TDAFW pump compartment door(s) to limit heat buildup withinthe pump compartment.

Initiate the Class IE 125 VDC power system (A, B, C, and 0 banks) loadshed sequence.

The ADV control system can be remotely operated for a minimum of 16 hour1.851852e-4 days 0.00444 hours 2.645503e-5 weeks 6.088e-6 months sbased on ADV accumulator nitrogen design (Reference 8, UFSAR Section9.5.9). The ADVs can also be manually operated in the Main Steam SupportStructure (MSSS) building.

The SG pressure will be controlled above 155 psiaby manipulating ADVs to maintain the desired RPM for continuous operation ofthe essential TDAFW pump.The essential TDAFW pump delivers CST inventory to the SGs and SG levelis maintained at the upper limit of narrow range, to provide additional operational margin for recovery should the essential TDAFW pump degradedue to unanticipated conditions (Reference 34). The CST has sufficient waterinventory for phase I RHR without the need for additional makeup.The strategy described here was simulated using site specific CENTSanalyses (Reference

34) and is consistent with NRC approved industrygeneric position use of CENTS code for ELAP evaluation.

These analysesshow that approximately 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months into the event the RCS is cooled to long termstandby pressure and temperature, two phase natural circulation isestablished, and the plant will be in a stable coping condition.

Reactivity management is minimal during this phase; reactivity margin inleakage scenarios (range of RCP leakage modeled 0-25 gpm / RCP) isdominated by the shutdown rods, which provide enough negative reactivity such that boron injection from the SITs can be ignored and the core will stillremain at more than 2% delta p shutdown.

Therefore, even if the SITs do notinject, the core will remain subcritical.

Manual operator actions are limited forthe reminder of phase 1 to minor ADVs adjustments after ADV accumulator nitrogen is depleted.

Reference 34 and Reference 16 provide additional details.Phase 2 StrategyAs shown in Table 5, Item 15, RCS inventory safety function will be challenged as a result of RCS volume contraction during cool-down, RCP seal leakage,SIT depletion and loss of natural circulation at approximately 35 hours4.050926e-4 days 0.00972 hours 5.787037e-5 weeks 1.33175e-5 months into theevent (if all RCP seals develop the maximum leakage of 25 gpm).Consequently, control room staff will initiate RCS borated makeup capability earlier by staging two (2) portable 480 V FLEX generators.

Connections to vital plant essential 480 V buses can be established usingFLEX designed and installed primary or alternate connection boxes at externalPage 23 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 3building locations that are easily accessible and require minimum operatoraction for breaker alignment at control building ground elevation.

Capabilities are available to connect to either train of the Class 1 E 480 V switchgear andalign to the required equipment in that train.RCS borated makeup can then be started via one of the two permanently installed charging pumps or by using the FLEX motor driven portable pump(high pressure RCS injection pump). The source of water for RCS injection isthe RWI at 4,000-4,400 ppm boron. RCS inventory makeup from the RVVT issufficient to last for approximately 10 days.FLEX portable 480 V generator sets will also provide power to critical electrical loads such as vital instrumentation, two of four trains of battery chargers andbattery compartment exhaust ventilation fans, and to the safety relatedessential diesel fuel oil transfer pump. If required, portable generator sets aresized with additional capacity to provide power to non-critical loads such asunit essential lighting and control room air recirculation unit.If required in the Phase 2 strategy diesel powered FLEX SG pumps can beused for reactor core cooling and heat removal when decay heat is notsufficient to drive the TDAFW pump. The source of the supply water forfeeding the SGs is the seismically qualified CST and seismically robust RMWTto be used to supply water for feeding the SGs.Mechanical and Electrical modifications required for the use of FLEXequipment are detailed in Section 4.4.Phase 3 StrategyPhase 2 strategies will continue for Phase 3 with the addition of secondary makeup to ensure coolant is available for the SGs to perform the core coolingsafety function.

To transport this water, a temporary pipeline will be installed from station reservoirs to the units. Equipment and components for thepipeline are strategically distributed and stored along the implementation routeonsite and deployment will begin as soon as external resources have accessto the site.As the FLEX ELAP event proceeds, the decay heat produced by the nuclearfuel will decrease.

Initially, ADVs will be closed to maintain SG pressure;

however, eventually, the steam output will not be sufficient to run the essential TDAFW pump. Prior to loss of functionality of the essential TDAFW pump, theFLEX SG makeup pump will be staged and placed into operation.

During Phase 3, National SAFER Response Centers (NSRC) equipment forPVNGS will be staged, including generators, boration and water purification equipment, and other redundant capabilities.

If required, NSRC equipment willbe used to continue Phase 3 coping strategies or transition to recoveryPage 24 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 3strategies.

PVNGS will exit the FLEX ELAP event if, and when, the ultimateheat sink is re-established and the unit(s) achieves cold shutdown.

4.2. Reactor Coolant System at Lower ModesThe strategies for lower modes (RCS vented) are not engineered to the extentof strategies for the RCS at 100% power (Section 4.1); this is consistent withthe NRC approved industry position (Reference 18). Due to the large anddiverse scope of activities and configurations for any given nuclear plantoutage (planned or forced),

industry established guidance (Reference 81 andReference

82) has concluded that a systematic approach to shutdown safetyrisk identification and planning, such as that currently required to meet theMaintenance Rule [10 CFR 50.65(a)(4)]

along with the availability of the FLEXequipment, is the most effective way of enhancing safety during shutdown.

The term 'lower modes' in this report, is defined as the time that the RCS isopen to the containment environment and steam generators are decoupled from the ROS; the SG system no longer provides a functional method toremove decay heat. Lower mode strategies are applicable to outages (plannedor unplanned) during unit shutdown or start-up.

Two strategies will bediscussed herein:* Condition 1: RCS is open to containment with restricted flow path(pressurizer manway open); core is fully loaded. Event starts at least 48hours after outage start (reactor shutdown).

Condition 2: RCS is open to containment with the reactor head lifted andUGS/internals removed; core is fully loaded. Event starts at least 72hours after outage start (reactor shutdown).

Due to the small fraction of the operating cycle that is spent in an outagecondition, the probability of a BDBEE occurring during any specific outageconfiguration is very small. A minimal set of higher level strategies have beendeveloped and are incorporated into lower mode FSGs (Reference 69).Additionally, in accordance with the NEI white paper endorsed by the NRC(Reference 18), APS has incorporated the supplemental guidance provided inthe NEI position paper entitled "Shutdown

/ Refueling Modes" (Reference 97)into the shutdown risk process and procedures (Reference 71 and Reference 73). These procedures ensure that the lower mode FLEX strategies can beaccomplished during outages.APS will pre-stage critical FLEX equipment prior to each outage at designated seismically qualified pads to reduce deployment time and risk. Pre-staged equipment includes a generator set to energize the vital bus, diesel drivenRCS lower mode makeup pump (also called the SG makeup pump, see TablePage 25 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 32), and SFP makeup pump. This equipment will be fueled but not attached toexternal FLEX connections.

The staging location meets the seismic class 2over seismic class 1 (2/1) interaction requirements.

Phase 1 StrategyIn condition

1. coping is achieved per station guidelines and procedures forloss of all power during lower modes (Reference 69 and Reference

70) whichestablishes

lineups, initial conditions, and prerequisites for RCS inventory makeup. During this phase, gravity drain is established to the RCS from theRVVT. The RCS inventory will be replenished and stabilized and fuel in thecore is cooled by establishing a boiling regime (nucleate boiling).

In condition 2, the refueling pool is flooded by RW/T inventory to a plantnominal elevation of 138 ft. Heat capacity of the refueling pool inventory issufficient to delay the pool boiling to approximately 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months after the initiating event (Reference 45); thereafter core cooling is established by nucleateboiling.Phase 2 StrategyIn condition 1, coping is achieved per station FSG procedure for loss of all ACpower during lower modes (Reference

69) which establishes

lineups, initialconditions, and prerequisites for RCS inventory makeup. During this phase, aFLEX pre-staged diesel driven RCS lower mode makeup pump is used toinject RVVT borated water (at greater than 4,000 ppm) into RCS cold legsthrough High Pressure Safety Injection (HPSI) system headers.

An analytical boil off rate is established as a guide for an initiating event at 48 hours5.555556e-4 days 0.0133 hours 7.936508e-5 weeks 1.8264e-5 months aftershutdown of a unit.The flow requirement is equivalent to the boil off with consideration given topotential leakage.

Also, guidance has been provided to minimize boronsaturation

/ precipitation within the RCS by an additional flow requirement thatwill flush the system, if required (Reference 43). FSGs will maintain boronconcentration below the saturated solUbility concentration at the reactorcoolant boiling point of 50,000 ppm boron (see Request for Additional Information

[RAI] 34 in Reference 11). The borated water inventory in theseismically qualified RWTI provides makeup to ROS for a minimum of 50 hour5.787037e-4 days 0.0139 hours 8.267196e-5 weeks 1.9025e-5 months safter initial ELAP. To prolong the coping time, the seismically qualified CSTvolume will be available for diluting the RW'T. The governing procedure provides an option of diluting the RWVT inventory by 50 percent prior toinjection.

These actions will double the coping time.In condition

2. coping is achieved per station FSG procedures for loss of allpower during lower modes (Reference

69) which will allow the refueling pool toboil down to approximately 12 inches above reactor vessel flange. Level ismonitored in the control room using seismically designed pressurizer levelPage 26 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2 and 3instrumentation.

The refueling pool water inventory is sufficient to keep fuelassemblies cool until injection is established at approximately 50 hours5.787037e-4 days 0.0139 hours 8.267196e-5 weeks 1.9025e-5 months .Phase 3 StrategyFor both condition 1 and 2, a unit in refueling would rely on the boration skidand purification unit from the NSRC or onsite equipment with alternative watersources from the other units. To achieve this, borated water inventory stored inthe RW-Is of the two non-outage units may be used.UHS Restoration The UHS restoration strategy could be to operate the UHS, via use oftemporary power sources from onsite or offsite resources to power one of theessential Class 1 E trains supporting one of the two redundant seismically qualified spray ponds (UFSAR Sections 2.4.11.6, 3.8.4.1.6, and 9.2.5,Reference 8). UHS inventory can be continuously replenished using the 85 or45 acre water reservoir using the temporary pipeline built after ELAP (seePhase 3 in Section 4.1). It should be noted that the RCS boron concentration in the reactor vessel and refueling pool during phase 3 would be approaching 50,000 ppm boron. Since RCS injection can be achieved through HPSI coldleg nozzles, injection of non-borated water for a limited time will be permissible for conditions 1 and 2 as a final option to keep the fuel assemblies cool.4.3. Systems, Structures, Components Essential Turbine Driven Auxiliary Feedwater PumpThe essential TDAFW pump will automatically start on low SG level andprovide AFW flow to the SGs following an ELAP. The essential Turbine DrivenAuxiliary Feedwater Pump system is described in Sections 3.9.3.2.1.1.5 and10.4.9.2 of the PVNGS UFSAR (Reference 8). The components supporting theessential TDAFW steam driven pump and flow path for this coping strategy arepowered by the essential Class 1 E battery system. Long term functionality during ELAP is evaluated by identification and selection of key attributes of theessential steam driven pump. A long term coping RCS pressure andtemperature were selected based on actual pump testing to minimize thepossibility of turbine or pump degradation, or trip.The control system Failure Modes Effects Analysis (FMVEA) was performed toidentify key components in the control system that may be susceptible tofailure as a result of higher than normal essential TDAFW pump compartment temperature conditions as result of HVAC loss due to ELAP. Using FMEAresults a GOTHIC (Reference 83, refer to Section 2.2 for analysis discussion) best estimate analysis was performed to predict a time dependent temperature profile within the compartment.

It was concluded that to mitigate thetemperature rise, a time dependent operator action of opening the accessdoors or opening the access hatch at the 100 ft. elevation of the MSSSbuilding at about 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months post ELAP will add margin to the environmental Page 27 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 3condition degradation within the essential TDAFW pump compartment.

Thecompartment analysis shows that taking this mitigating action will limit thetemperature rise to less than 130 degrees F for the remainder of the event(see RAI 22a in Reference 11 and Reference 33).The FSGs require operator action to open an essential TDAFW pumpcompartment door (80 ft. and 100 ft. elevation) in 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months (see Table 5, Item 8in this report).

Therefore, the station essential TDAFW Pump is capable ofmitigating ELAP through phases 1 and 2. The core cooling safety function maybe transferred to a portable diesel driven SG makeup pump during phase 2 or3 of ELAP during startup of the plant (early fuel cycle) if the residual coredecay heat is not sufficient to generate required secondary steam pressure forthe essential TDAFW Pump to function.

In the event that the essential TDAFW pump fails to start, procedures directthe operators to manually reset and start the pump (which does not requireelectrical power for motive force or control).

The pump is only needed for plantoperational modes 1-4 FSGs (Reference

68) and it is not utilized in lowermodes.Reactor Coolant Pump and Pump SealsThe PVNGS RCPs are CE-KSB (Klein, Schanzlin

& Becker) pumps withmodified three-stage hydrodynamic seals supplied by Sulzer.PVNGS has performed a plant-specific evaluation (Reference 34), thatconsidered RCS pump leakage rates ranging from 1-25 gpm per pump. It isassumed that leakage starts immediately after the initiating event. The leakageselected is consistent with NUMARC 87-00 Station Blackout (SBO) guidance(Reference 76), NRC guidance (Reference 7), and NRC safety evaluation forPVNGS regarding SBO (Reference 21). Using this leakage, analyses wereperformed to develop a set of critical operator actions to transition from FLEXphase 1 to phase 2 (refer to Table 5 for sequenCe of events).Analyses using lower leakage rates support reactivity management and FSGshave operational margin. ROP seal leakage is expected to be insignificant ifthe initiating event occurs during lower mode operation; RCS system pressurewould be at atmospheric pressure plus a water deferential head, which isdependent on the refueling evolution water level.Atmospheric Dump ValvesAtmospheric Dump Valves (ADV) are described in Section 10.1 of the PVNGSUFSAR (Reference 8). ADVs are needed for plant operational modes 1 -4FSGs (Reference

68) and this equipment is not utilized in lower modes.ADVs (there is one ADV per steam line for a total of four) are pneumatically driven with seismically qualified back up nitrogen accumulators.

The controlsystems for ADVs are powered by a safety related essential Class 1 E, DCPage 28 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 3power source. These valves will be Operated from the control room duringinitial stages of an ELAP to achieve a rapid cool-down of the RCS. Asymmetric RCS cool-down will establish natural circulation within the primarysystem. Remote functionality from the control room will be maintained as longas a backup nitrogen source is available.

The nitrogen inventory may bedepleted in as soon as 16 hours1.851852e-4 days 0.00444 hours 2.645503e-5 weeks 6.088e-6 months . Should nitrogen be depleted, the ADVs canbe manually operated by trained operators in the Main Steam SupportStructure (MSSS).Unlimited access to the MSSS is possible since the building remains habitable during an ELAP event. Additionally, the nitrogen supply can be remotelyreplenished at an exterior location of the MSSS building.

CENTS simulation (see Section 2.2 for analysis discussion) shows minimal manipulations ofADVs are required, post cool-down, to maintain the secondary side above therequired pressure; therefore, operator burden is minimal.Batteries The essential Class 1 E 125 Volt direct current (DC) systems are described inSection 8.3.2 of the PVNGS UFSAR (Reference 8). The four independent safety related battery banks and associated 125 VDC/120 VAC distribution systems are located within the control building, a safety related structure designed to meet design basis external hazards.

These battery banks areused to power required instrumentation, control systems, and valve operators during the postulated event.The Class 1 E battery duty cycle life for ELAP strategies is calculated inaccordance with the NEI position paper, which was endorsed by the NRC(Reference 17), using best available manufacturer discharge test data. Aconservative battery discharge capacity analysis (Reference

50) provides thebases for FSG operator actions to complete the load shed sequence on thestation battery Train "A" and "B" within 2 hrs. of the initiating event. This willensure 125 VDC/1 20 VAC power is available for at least 34 hours3.935185e-4 days 0.00944 hours 5.621693e-5 weeks 1.2937e-5 months after theinitiating event. At this time, FLEX portable 480 VAC, 800 kW dieselgenerators are deployed to supply AC power and recharge the battery banks(see Table 1 for the generator load list). Actual validation exercises showgenerator deployment time could occur well within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months of the initiating event. Therefore, ample operational margin exists in the strategy to provide anuninterrupted power source to maintain control room functionality.

Hydrogen generation is not a concern during the discharge cycle of batteries.

When 480 VAC diesel generators are deployed and prior to the start of thebattery charging cycle, station essential battery exhaust fans in the batterycompartments are started to eliminate build-up of hydrogen in the area.Additionally, analytical evaluation shows the hydrogen concentration in abattery compartment will remain below 2 percent at 130 hours0.0015 days 0.0361 hours 2.149471e-4 weeks 4.9465e-5 months after the start ofthe charging cycle if no ventilation is provided.

This concentration is below thePage 29 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2 and 34 percent flammability limit and provides additional operating margin to takeaction should essential HVAC fail (Reference 55, RAI 8 in Reference 11 andReference 57). Battery capacity as a result of an ELAP event during lowermodes of operation is not a concern since the 480 VAC generators will be pre-staged and within 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months into the event external AC power will be established to charge essential batteries.

Plant Primary Side Source of Borated WaterThe Refueling Water Tank (RWT) supplies borated water for the Emergency Core Cooling System (ECCS) and plant normal/refueling operation and it isdescribed in UFSAR Sections 3.8.4.1.8 and 9.3.4.2.1 (Reference 8). Therefueling water tank is a reinforced concrete structure (46.5 feet internaldiameter, 68 feet in height) located near the seismically qualified fuel building.

The RVVT has cylindrical walls approximately 2 feet thick. This structure isdesigned to withstand design basis SSE and tornado events. A seismiccategory I stainless steel wall and base-mat liner provides the internal watertight barrier to the concrete structure.

RWVT has a required boron concentration in the range of 4,000-4,400 ppm. Thetank's contents are maintained above 60 degrees F by two, redundant 25 kWelectric heaters which prevent the boron from precipitating.

During operational modes 1-4 the normal volume available is approximately 675,000 gallons(Reference 52). Thirty (30) days prior to outages borated water volume in thetank is procedurally increased to at least 720,000 gallons (Reference 71).Plant Secondary Side Sources of Cooling WaterThe Condensate Storage Tank (CST) provides the main source water for plantcool-down at the initial onset of the BDBEE and into Phase 2. This tank isdescribed in Sections 3.8.4.1.7 and 10.4.9.2 of the UFSAR (Reference 8). Thecondensate storage tank is a reinforced concrete structure (46.5 feet internaldiameter, 52 feet in height).

The CST is located approximately 175 feet plantnorth of the center of the containment structure.

The condensate storage tankhas concrete cylindrical walls approximately 2 feet thick. The structure isdesigned to withstand design basis SSE and tornado events. The condensate storage tank has a seismic category I stainless steel wall and base-mat liner.CST has a normal volume of 508,000 gallons during operational modes 1-4(Reference 59).Additionally, 445,000 gallons of water is available in the RMVVT (Reference 54), a designated Technical Specification backup source of water to the CST.RMVVT inventory can be manually aligned to the essential TDAFW pumpsuction.

The back-up function of RMVVT, as a source of water to the CST, isdescribed in Section 9.2.6.2 of the UFSAR (Reference 8).The seismic category 2 RMVVT is a flat bottom cylindrical stainless steel tankconstructed:

out of American Society for Testing and Materials (ASTM) SA240-Page 30 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2and 3304 material.

The seismic capacity of the tank is calculated as HighConfidence of Low Probability of Failure (HCLPF) following the EPRI NP-6041Guidance (Reference

77) methodology for flat bottom tanks. The HCLPFseismic capacity of the RMWT is calculated as 0.36 g (Design Basis SSE =0.25 g) (Reference 51). Therefore, it is concluded with high level of confidence that RMWT will be available post initiating event.In the highly improbable event of RMV-IT failure, procedural direction isincluded in the FSGs for methods of transferring water from the seismically qualified RWTI to CST during FLEX phase 2. A surplus of borated water will beavailable during operational modes in the RWTI since boil off from the SFP andmakeup to the RCS would be relatively small.Additional seismic capacity calculations were performed to establish integrity of non-seismic piping attached to the OST. HCLPF values calculated usingEPRI methodology concluded that all cases analyzed enveloped the designbasis SSE (Reference 53). Further, FSGs establish priority operator actionsincluding walk-down of high risk plant areas and isolation of possible leakpaths from the described tanks.4.4. FLEX Modifications in Support of Phases 2 and 3Plant changes described in this section have been implemented and reviewedpursuant to 10 CFR 50.59 consistent with the current licensing basis. Whenapplicable, the design requirements of 10 CFR 50 were applied instead of NEI12-06 (Reference 75).FLEX Primary Mechanical Connections, RCS Injection and MakeupThese modifications installed FLEX RCS pump suction (and RWTIconnections) and discharge tie-ins.

Easily accessible primary and alternate locations in each unit were selected.

Primary location including suction anddischarge piping are protected against the applicable external event. Analternate location within the auxiliary building was selected to providemaximum separation and protection against possible high wind events,although high wind external events are not applicable to PVNGS (see Section7). At least one of the two (primary and/or alternate) staging locations meetsthe seismic 2/1 interaction requirements.

Schematics of these externalconnections are shown in Figure 1 and Figure 4. Piping and components aredesigned and installed to SSE + 10% margin (see Section 7.1).Page 31 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2 and 3Primary RCS Tie-in Connection (FLEX pump discharge)

Primary RCS connection piping and associated components are tied into the existing 4 inch train A HPSI system header, between theoutboard containment isolation valve and containment structures.

Thistie-in location is selected to provide a direct injection path to the reactorcore and to minimize possible intermittent component failure that mayobstruct flow. Redundant manual containment isolation valves are alsoinstalled as part of this modification.

These valves are located as closeas practical to the containment boundary and are easily accessible fromthe 87 ft. platform in the auxiliary building.

The lower~auxiliary building ishabitable when operator access is needed, which is expected to bemore than 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months after the initiating event.The primary ROS tie-in piping is routed through the auxiliary building toan external location adjacent to the RWT, where the RCS pump wouldbe deployed.

At the deployment location two connection options areprovided:

1 1/ inch NPT connect for the modes 1-4 electric motor drivenhigh pressure RCS injection pumps (see Figure 1) and a 5-inch STORZfitting connection for low pressure injection into the RCS (see Figure 4)during modes 5 & 6 using the diesel driven RCS lower mode makeuppump (also called the SG makeup pump, see Table 2). Refer to Figure2 for the simplified r'outing.

Alternate ROS Tie-in Connection (FLEX pump discharge)

The alternate discharge connection ties into the existing 4 inch train BHPSI system header and has the same design as the primary discharge connection.

The alternate RCS tie-in piping is routed to the groundelevation of auxiliary building east -west corridor, adjacent to plantcharging pumps compartment, where the ROS pump may be deployed.

This internal location was selected as an alternate deployment locationdue to its ease of access and communication with the yard area throughthe large roll up doors. Although PVNGS screens out for high windrequirement per NEI 12-06 (Reference

75) guidance (see Section 7),this alternate location provides a high wind protected tie-in. Refer toFigure 3 for the simplified routing.Primary RCS Suction Piping (FLEX pump suction)A permanent connection to the existing RWT drain line is selected asthe primary RCS pump suction location.

A section of pipe and anisolation valve (ASME Section III Class 2), with 5-inch STORZconnector, are installed (see Figure 1 and Figure 4). This pipingextension is located in a FLEX added valve pit below grade and fittedwith a 3 inch carbon steel missile barrier for protection againstPage 32 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2and 3postulated tornado borne missile hazards.

Refer to Figure 2 for thesimplified routing.Alternate RCS Suction Piping (FLEX pump suction)To tie-in to the existing essential charging pump suction piping toenable RCS pump alternate

suction, 4 inch piping and valves areinstalled at the existing hydrostatic test connection flange immediately adjacent to valve 1 ,2,3PCHAV314, hydro-connection isolation valve.The FLEX line runs from the hydrostatic test flange in the chargingpump compartment to the adjacent hallway at the ground elevation where a FLEX added isolation valve and 5-inch STORZ fitting arelocated.

Refer to Figure 3 for the simplified routing.FLEX Secondary Plant Mechanical Connections, SG MakeupThese modifications installed secondary plant tie-ins for steam generator makeup and FLEX SG makeup pump suction piping (including CSTconnections) to support FSG strategies.

These tie-in locations are selected toprovide a direct injection path to the steam generators and to minimizepossible intermittent component failure that may obstruct flow. Additionally, theselected location provides the capability of symmetric natural cool-down, should it be needed, by manually opening additional valves.Redundant manual containment isolation valves are provided as part of thisplant modification.

These valves are located as close as practical to thecontainment boundary and are easily accessible in the train B AFW pumpcompartment.

Access to this compartment is provided through the 100 ft.elevation hatch and, at the point in time when access may be required, thevalve location is habitable.

The primary and alternate tie-in and deployment locations in each unit aresimilar and have been selected for ease of access. Locations of suction anddischarge piping are protected against the applicable external event. At leastone of the two staging locations meets the seismic 2/1 interaction requirements.

A schematic of these external connections is shown in Figure 5.Piping and components are designed and installed to SSE + 10% margin.Although provisions are made for attachment of the secondary makeup pump(SG makeup pump), FSGs do not require deployment of these pumps untilcore decay heat is reduced such that steam generator pressure is no longersufficient to support the requirements of the essential TDAFW pump.Primary SG Tie-in Connection (FLEX pump discharge)

Secondary plant connection piping and associated components tie-in tothe train B electrical auxiliary feedwater discharge piping to steamgenerator number 2, in the train B AFW pump compartment Page 33 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 3downstream of existing AFW isolation valve (1 ,2,3JAFBUV35) andContainment penetration (see Figure 5). The FLEX added line runs fromthe train B AFW pump compartment to condensate pipe tunnel andexits the plant permanent structure adjacent to CST. A 5-inch STORZconnection is provided at deployment location to tie-in the diesel drivenFLEX SG makeup pump. .Alternate SG Tie-in Connection (FLEX pump dischargqe)

Configuration of Alternate connection is similar design as the primaryconnection.

The connection for alternate is made to the train B auxiliary feedwater discharge piping to the steam generator number one in thetrain B AFW pump compartment downstream of existing AFW isolation valve (1 ,2,3JAFBUV34).

Alternate pipe runs parallel with the primary tothe location of deployment, refer to Figure 6.Primary Secondary Plant Tie-in Pipingq (FLEX pump suction)A permanent Connection to the existing 6 inch CST drain line providesthe primary suction source to the FLEX diesel driven, SG makeup pump.Specifically, a new section of pipe and redundant isolation valves, areinstalled (ASME Section III Class 3), and the piping is terminated at a 5-inch STORZ connector (see Figure 5). The existing CST valve pit isextended to accommodate the FLEX installed piping and valves. Theequipment is located beneath grade and fitted with a 3-inch carbonsteel missile barrier for protection from postulated tornado missilehazards.Alternate Secondary Plant Tie-in Pipinaq (FLEX pump suction)*

Alternate secondary plant makeup is composed of new 6 inch piping,new inboard and outboard manual isolation valves, and a 5-inchSTORZ standard connection at the location of diesel driven SG makeuppump deployment (see Figure 5). The FLEX added line runs from aconnection point at the FLEX SG makeup pump staging area on thenorth wall of the Condensate Transfer Pump House (adjacent to theCST) through a new penetration in the Condensate Transfer PumpHouse north wall. It then proceeds south in the CST pipe tunnel to anexisting penetration through the Main Steam Support Structure (MSSS)(train B AFW Pump compartment) wall.Once inside the pump compartment the piping will tie-in to existing 8-inch line downstream of CST and RMWT suction check valves1 ,2,3PAFBV022 and 1 ,2,3PAFBV009.

The inboard isolation valve islocated in the train B AFW pump compartment and the outboard valveis located outside at the north wall of the Condensate Transfer PumpHouse, refer to Figure 6.Page 34of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 3Hatch Alteration 80-1 00 ft. of Auxiliary BuildingA new (FLEX added) manway hatch in the MSSS 100 ft. elevation floor toaccess the 80 ft. elevation train A essential TDAFW compartment will providebackup ventilation capabiiity for the essential TDAFW pump compartment during an ELAP event. Additionally, this hatch (and added access ladder)provides a new ingress and egress path, if the existing access door is notfunctional and/or obstructed.

The new manway hatch is fitted in the existingequipment hatch area.Gravity Flow Diesel Fuel Oil Day Tank FLEX Supply LineThis modification provides the capability to gravity drain from the essential diesel day tank drain line (-elevation 130 ft.) to the 104 ft. elevation of theDiesel Building near the missile doors (inside) using 1 1/2/ inch piping. Themodification provides initial "first fill" of fuel oil for portable equipment neededfor phase 2. Once the 480 VAC diesel generators are started and aligned withstation electrical system, the essential day tanks will be filled as needed fromthe station seismically qualified 7-day tank by the installed essential stationfuel oil transfer pumps. This will provide a sufficient source of diesel fuel forFLEX mitigation strategy.

Electrical Modifications FLEX Primary and Alternate 480 VAC Electrical Connections This electrical modification provides AC power to the high pressureRCS injection pump, capability to charge batteries, and power toventilation fans, if needed, following entry to FLEX phase 2.This modification installed FLEX electrical offshore tie-ins to station train"A" and 'B" essential 1 E Class 480 VAC load centers.Primary and alternate locations to make connections to generators ineach unit were chosen for ease of access. The primary locationconnection boxes are protected against the applicable external event.The alternate location was selected outside the diesel building (planteast) to provide maximum practical separation and protection againstpossible high wind events, although high wind external event is notapplicable to PVNGS. At least one of the two staging locations meetsthe seismic 2/1 interaction requirements.

Physical layout and schematic of these external connections are shownin Figure 7 and Figure 8. Conduit routing and components are designedand installed to SSE + 10% margin. The external cable connections arecolor coded and use a standard molded locking connector per NSRCrecommendation.

Manual operator actions are required in the controlbuilding at the 100 ft. elevation (ground) to align the portable generators to the breakers in the Class 1 E load centers.

This location is expectedPage 35 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2and 3to be at ambient conditions, since no equipment is energized in the areaprior to this action.The eight 800 kW FLEX generators, as required for N+I stipulations, will be stored onsite. Two FLEX generators are deployed per unit andstaged plant south of the diesel building.

FLEX generators are trailermounted and easy to deploy. A set of dedicated color coded cables willbe stored with each generator.

Generators and FLEX permanently installed boxes are color coded to insure correct phase rotation duringthe deployment.

Each FLEX generator will be grounded via a flexible cable to a groundtest well which will provide an accessible ground in the staging area.These generators, cables, and protection devices are sized to repowerkey 480 VAC Class 1 E load centers (load centers are normally isolatedfrom FLEX connections by use of mechanically locked open breakers).

The FLEX generators are to power essential loads identified in Table 1.These loads are energized manually per FSGs.FLEX electrical connections for the primary and alternate AC motordriven hicqh pressure RCS iniection pumpEssential 480 VAC power for the motor driven high pressure RCSinjection pumps are provided at two locations.

The primary location isnear the RWVT (ground elevation, yard area just outside the western wallof the auxiliary building).

The alternate location is located between thecharging pump compartments and the east penetration wrap (groundelevation, auxiliary building east corridor).

Two new (FLEX added)redundant circuits (Train "A" and "B") are routed from existing sparecubicles in the Class 1 E MCCs. A FLEX added breaker provides powerto 100QA receptacles (Blue Bell DR1 00) as source of power for the motordriven high pressure RCS injection pumps..Train isolation is achieved by new Class 1 E qualified disconnect switches installed adjacent to the corresponding MCC. At least one ofthe two staging locations meets the seismic 2/1 interaction requirements.

Physical layout and schematic of these connections are shown inFigure 9 and Figure 10. Conduit routing and components are designedand installed to SSE + 10% margin.Page 36 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2 and 3Defense-in-Depth Primary and Alternate 4.16 kV AC Electrical Connections The 4.16 kV modifications are not required for FLEX mitigation strategies at PVNGS. The unique stand-alone seismic UHS andsources of water at PVNGS, in combination with Section 2.1,Assumptions 19 and 20, enable restoring the UHS by energizing anessential train of shutdown

cooling, which is an effective method formitigation at PVNGS. Electrical modifications for this defense-in-depth option provide AC power to a Train "A" or "B" ECCS system and itsauxiliary components needed to cool the plant from an RCS shutdownentry condition to cold shutdown; in addition it would cool the SpentFuel Pool via the UHS. This defense-in-depth system is also a 100percent back up to 480 VAC FLEX, described above.These modifications installed FLEX electrical tie-ins to station Train "A"and "B", 1E Class 4.16 kV busses sized for receiving power from 4.1.6kV generators-(synchronized generators).

Similar to the 480 VACmodification, primary and alternate locations in each unit were chosenfor ease of access. At the primary location, connection boxes areprotected against the applicable external event. An alternate

location was selected outside the diesel building (plant west) to PrOvidemaximum practical separation and protection against possible high windevents, although high wind external event is not applicable to PVNGS(per Section 7.3). At least one of the two staging locations meets theseismic 2/1 interaction requirements.

Physical layout and schematic of these connections are shown inFigure 11 and Figure 12. Conduit routing and components, including transfers

switches, are designed and installed to SSE + 10% margin.The external cable connections use a standard NEMA connector.

Sufficient generation capacity (gross 4 MWe) for 1 of the 3 units arestored in the EESF (refer to Section 8.1). The remainder of 4.16 kVgenerators will be delivered to site, when needed, by the NSRC.Generators are staged plant south of the diesel building.

4.16 kV*generators are trailer mounted and easy to deploy. Dedicated cablesare stored at the site for the generators, including NSRC generators.

Page 37 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 34.5. Key Reactor Parameters Mode 1 Instrumentation:

One single instrument channel train ("A" or "B", as a result of load shed) oflisted safety instrumentation is required for PWRs in Phase 1 for reactor corecooling and heat removal strategy:

SG Level/Pressure(*)

RCS Pressure/Temperature

Containment PressureAt PVNGS the list of instrumentation below will be Powered by essential station batteries at the start of the initiating event. When an ELAP is declared, DC electrical load shedding will begin. One train of instruments is maintained.

Once the onsite portable 480 V diesel generator set is staged and functional, batteries will be recharged to maintain a supply of power to thisinstrumentation.

SG Level:* Steam Generator Level (wide range (WR))SG Pressure:

Steam Generator PressureRCS Temperature:

Core Exit Thermocouples (CETs)* Thor, Tco=d (two Hot Leg and two Cold Leg on the same loop)* Subcooling/Saturation Margin (ROS and CET)RCS Pressure:

RCS Pressure (WR)As a result of load shed and breaker alignments the following additional instrumentation is also available to the operator for monitoring:

Safety Injection Tanks IA and lB Level and Pressure* Parameters can be read out locally, when required, using a portable instrument, as required bySection 5.3.3 of NEI 12-06. Portable FLEX hand-held instruments are available at pre-designated locations.

The use of these instruments is detailed in the FSGs.Page 38 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2and 3* Pressurizer Level instruments

Reactor Vessel Level Monitoring System (RVLMS)* ADV Positions

Essential TDAFW Pump flow to each SG (A train power)* Pressurizer Level* CST and RVVT levelMode 5 and 6 Instrumentation:

Core Exit Thermocouples

Thor, T~cod (two Hot Leg and two Cold Leg on the same loop)* Pressurizer level instruments

CST and RWT level* RCS Pressure (WR)5. Spent Fuel Pool (SFP) CoolinglInventory StrategyStrategies are developed for an ELAP following BDBEE (Section 2.1, Assumption 2).Two distinct bounding scenarios are considered:

Power Operation

-Initial bounding condition is a limiting SFP decayheat during power operations (e.g., at start of power operation after ascheduled refueling outage)* Full core off-load

-Initial bounding condition is the maximum SFPdecay heat following full core off-load (beginning of refueling outage,100 hours0.00116 days 0.0278 hours 1.653439e-4 weeks 3.805e-5 months after reactor shutdown)

The PVNGS Spent Fuel Pool is designed to the guidelines of Regulatory Guide 1.13,Revision 0 (Reference 26). The fuel building, pool and liner, and fuel rack areseismically designed.

As applicable, surrounding SSCs are also designed toeliminate seismic 2/1 interactions.

The seismically qualified physical boundary of theSEP is defined as the inner gate located between the spent fuel pool and the caskloading pit, the boundary valve on the transfer tube on the fuel building side, drainvalve and the spent fuel pool liner.The Palo Verde SEP design incorporates passive safety features such as physicalarrangements and siphon holes in piping to eliminate the probability of uncovering spent fuel due to system failures.

Since the SEP boundary cannot be breached as aPage 39 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 3result of a seismic event or other mechanistic

failures, fuel remains covered at alltimes; inventory losses are negligible as a result of sloshing and minimal boundaryleakages.

However, PVNGS has the capability to remotely spray spent fuel storedin the pool by deploying B.5.b equipment (monitor nozzles) if a SFP failure eventwere to occur. The capability of B.5.b equipment was reviewed and accepted byNRC under security

.order (Reference 32).The engineered capacity of the FLEX SFP system (makeup pump, nozzles, andSpiping) exceeds the flow needed to match the boil off rate in the considered scenarios.

The time to boil and boiling rate are based on decay heat calculated using the guidance of NRC Branch Technical Position APCSB 9-2 (Reference 22)and as described in UFSAR Section 9.1.3 and Table 9.1-2 (Reference 8). The twobounding scenarios analyzed are: (1) maximum normal operation in which the heatload in the pool is administratively controlled to less than 12.6E+6 Btu/hr. and (2) themaximum normal/emergency refueling heat load of 4.7E+7 Btu/hr.The time to boil calculations are based on the SFP normal elevation of water andinitial SEP bulk water temperature of 125 degrees F (Reference

36) and includesinventory losses due to seismic sloshing, loss of non-seismically qualified pipingentering the SEP, and SEP boundary leakages.

Evaluations were performed inaccordance with the NRC endorsed boron mixing position paper (Reference

19) tovalidate that SEP fuel measure of criticality (Keff) remains less than one (<1) at zero(0) ppm boron when bulk water in the SEP is boiling (Reference 58).5.1. Spent Fuel Pool Cooling Strategy, ELAP During Power Operation Phase 1 StrategyIn Phase 1, as a result of ELAP, cooling to the SEP will be lost and SEP boilingwill occur approximately 11 .5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months after the initiating event. Boiling will resultin SEP water level decreasing to 10 ft. above the active fuel stored in the fuelrack approximately 39 hours4.513889e-4 days 0.0108 hours 6.448413e-5 weeks 1.48395e-5 months after the initiating event. An operator action isconservatively taken to open the Fuel Building rollup door to keep the buildingat atmospheric pressure and temperature.

Phase 2 StrategyIn preparation for Phase 2 portable diesel powered SEP makeup pumps aredeployed at pre-designated external locations to supply RWT water to the SEP(see Figure 13, Figure 14, and Figure 15). This pump provides inventory makeup sufficient for SEP leakages (31 gpm) and boil off (27 gpm) (Reference 36). Therefore, a SEP makeup flow rate of 58 gpm will maintain adequate SEPlevel at 10 ft. above the fuel during power operation in the core not off-loaded scenario.

FSGs (Reference 68 and Reference

69) direct operators to fill the SEP using abatch process.

FLEX SEP makeup pump would be operated at 150 to 200gpm to fill the SEP to a predesignated elevation.

This strategy reduces thePage 40 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2 and 3possibility of water losses and assures discharge nozzles are operated atoptimum conditions.

The normal RVVT water level is sufficient to provided makeup to the SEPbeyond 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .Phase 3 StrategyIn Phase 3 PVNGS will continue the Phase 2 strategies to provide makeup tothe SFP. Makeup will be provided to the RWVT from the station reservoirs usinga pipeline and pumps sized to match the decay heat.5.2. Loss of Power with a Full Core Off-Load (at least 100 hours0.00116 days 0.0278 hours 1.653439e-4 weeks 3.805e-5 months intorefueling)

The FLEX actions during a full core off-load are nearly identical to thosedescribed above in Section 5.1, with only the timing for those actions and theflow requirement for the FLEX SFP makeup pump being dissimilar.

Thedifferences are described below:Phase I StrategySEP boiling will occur approximately 3.3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months after the initiating event. Thefocus of Phase 1 actions is establishing the fuel building vent path at 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months ,similar to Section 5.1.Phase 2 StrategyIn Phase 2, based on fuel core decay heat load as described in Section 5, timeto boil is estimated at 3.3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months after an ELAP. As a result of boiling, SEP levelwill reach 10 ft. of water above the irradiated fuel assemblies in approximately 17 hours1.967593e-4 days 0.00472 hours 2.810847e-5 weeks 6.4685e-6 months after the initiating event. This would result in entry to FLEX phase 2in 17 hours1.967593e-4 days 0.00472 hours 2.810847e-5 weeks 6.4685e-6 months verses the 39 hours4.513889e-4 days 0.0108 hours 6.448413e-5 weeks 1.48395e-5 months in the scenario described in Section 5.1.The SEP makeup flow rate for the full core off-load case is 131 gpm (100 gpmboil off and 31 gpm for system leakage)

(Reference 36). The source of waterfor makeup to the SEP in lower modes is the CST, which does not containborated water. As stated in Section 5, the SFP criticality evaluation shows thatthe pool will remain in a sub-critical configuration during the event.FSGs direct operators to deploy the FLEX SFP makeup pump and establish suction from CST and initiate SFP makeup prior to inventory of pool reaching10 feet above the active fuel (Reference 69).Page 41 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 3Phase 3 StrategyPhase 3 includes (similar to Section 5.1) the use of additional water andresources at 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .5.3. Systems, Structures, Components Refueling Water Tank -Source of water during power operation The Refueling Water Tank (RWT-) is described in Section 4.3 of this report.The RWVT is the primary source of water to replenish inventory loss and boil offfrom the SEP during an ELAP at power operation.

Other sources of water maybe used if RWT, or its associated SSCs, needs to be maintained.

Condensate Storage Tank -Source of water during a full core off- loadThe Condensate Storage Tank (CST) is described in Section 4.3 of this report.The CST is the primary source of water for replenishment flow to makeup forinventory losses and boil off from the SFP during an ELAP coincident with afull core off-load.

Other sources of water may be used if CST, or its associated SSCs, needs to be maintained.

5.4. SFP Cooling Modifications FLEX Mechanical and Electrical DesignThis FLEX modification establishes coping capability to prevent damage to fuelin the Spent Fuel Pool (SFP) for an extended loss of AC power (ELAP) as aresult of a Beyond Design Basis Event (BDBE). A primary hose connection atan outdoor location (outside plant north wall of the Fuel Building) and analternate indoor hose connection (Fuel Building truck bay) are provided tosupply makeup water to the Spent Fuel Pool (refer to Figure 13, 14 and 15 forschematic and simplified piping).A portable diesel driven pump skid will be connected to one of these hoseconnections to provide makeup water from the OST if the event occurs duringa full core off-load and / or the Refueling Water Tank (RWTI) if the event occursduring modes 1-4 (refer to Figure 14 and Figure 15 for schematic andsimplified piping).

Modifications to provide suction from the RVVT or OST aredescribed Section 4.4 this report. Additionally, "Y" connections are stored withportable pumps to establish multi-suction header if required.

The design modification installed redundant headers of 4 inch seismically qualified stainless steel pipe and supports on the inside of the Fuel Buildingtruck bay (east of the roll-up door) on the ground elevation to a location on the*plant north wall of the Fuel Building, near the middle of the SFP on the 140 ft.elevation in the Fuel Building (refer to Figure 13, Figure 15, and Figure 16).5-inch STORZ adapters are used at the pipe connection to the portable pumpconnection.

Page 42 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2 and 3Flow directing nozzles are located along the length of the spent fuel pool plantnorth wall; the height of these headers was selected for optimum streamtrajectory.

A redundant header for each of the FLEX added makeup waterpathways will be utilized to eliminate the need for isolation valves or checkvalves in each of the pathways (Figure 16).5.5. Key Spent Fuel Pool Parameters The key parameter for the SFP cooling/inventory strategy is the SFP waterlevel. The SFP water level is monitored by newly installed, redundant, DCpowered Spent Fuel Pool Level Instrumentation that meets the requirements set by Order EA-12-051 (Reference 9, APS Letter 102-06669 for OrderEA-12-051 Overall Integrated Plan). RWVT and CST level instrumentation areavailable.

6. Containment Integrity Strategy6.1. Containment Integrity at PowerAll Three Phases of FLEXAt the time of an ELAP event containment will be isolated as a result of ESFactuation and this condition will be verified by control room personal usingexisting plant procedures.

A containment evaluation has been performed based on the boundary conditions described in Section 2 of NEI 12-06(Reference 75). Computer code GOTHIC (Reference

83) was used to predictthe environmental conditions (pressure and temperature) within theContainment.

The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months post ELAP pressure and temperature in thecontainment (Reference

44) is estimated to be less than 20 psia and200 degrees F based on a total RCP seal leakage of 100 gpm at the start ofthe event (refer to Section 4.3 of this report).A conservative, long term 30 day containment pressure GOTHIC modelpredicts that containment will remain well below the 60 psig design pressure.

Therefore, no operator action is required;

however, the FSGs (Reference 68)provide guidance for monitoring containment pressures as a trending tool forRCS leakage, in addition to continuing assessment of the containment integrity.

6.2. Containment Integrity during Modes 5 and 6 (fuel in reactor vessel and inthe containment with no fuel movement)

All Three Phases of FLEXAn ELAP event during modes 5 and 6 would result in possible overpressurization of the containment.

As described in Section 4.2 of this report,Page 43 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 3refueling pool/IRCS will start to boil as a result of decay heat and containment pressure will increase.

To eliminate possible challenge to containment integrity a passive vent path is provided through the 42 inch refueling purge system(see Figure 17). Station administrative procedure 400P-9ZZ23 (Reference 71)will implement a refueling purge (CP) system alignment before establishing ahot leg vent during Mode 5 in each outage to provide an open path through the42 inch containment refueling purge system to the outside environment.

Additionally (not required by FLEX), the plant vent radiation monitors (RU-143/144) are powered after ELAP using a 480 V 800 kW generator to monitorfuel conditions and radioactive releases.

The containment will be vented through the 42 inch purge for the duration ofthe event and the control room will have the capability to isolate containment, should fuel failure occur, using one of the containment isolation valves.6.3. Systems, Structures, Components Containment integrity is maintained beyond 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months without reliance on plantSSCs during ELAP at power conditions.

Containment integrity in lower modesis described below.Containment Purge System (CP) (Modes 5&6 only)Containment purge system is described in section 9.4.6 of the UFSAR(Reference 8). The normal purge system for the containment consists of arefueling purge and a power access purge. The refueling purge train is usedfor high flowrate purge during refueling and is closed during normal powergeneration.

It consists of a supply air handling unit and an exhaust fan asshown in Figure 17. Although the majority of the system is non-quality, containment isolation dampers are seismically qualified.

In addition, many ofthe components that are installed inside containment are designed to seismic2/1 interaction requirements.

To mitigate an ELAP during refueling and eliminate containment pressurization, the system is opened to the environment prior to establishing ahot leg vent (RCS is open -SG is decoupled).

The system alignment will besuch that valves 1 ,2,3CPA-UV-2B and 1 ,2,3CPB-UV-3B are open (thesedampers are designed to "fail as is" and they will not change position as aresult of ELAP). Additionally, administratively in each outage, damper1 ,2,3CPN-M05A will be temporarily modified by physical restraint

("gag") of thedamper blade to eliminate the possibility of path closure, should the flowconduits survive the initiating event (Reference 63).6.4. Key Containment Parameters One train (A or B train) of listed instrumentation is recommended for all modesfor containment integrity:

Page 44 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2 and 3e Containment Pressure6.5. FLEX Modifications No permanent modifications were needed to maintain containment integrity.

7. Characterization of External HazardsAPS has evaluated PVNGS for external hazards based on the screening guidance inNEI 12-06 (Reference

75) and determined that the seismic and extreme heathazards are applicable to PVNGS. External

flooding, high wind, and extreme coldhazards were found not to be applicable to the PVNGS site.Flood and seismic re-evaluations pursuant to the 10 CFR 50.54(f) letters of March12, 2012, are completed and it has been concluded that the original design andlicensing bases remain bounding.

It has been concluded, using "state of the art"methodologies, that the PVNGS site remains a "dry site" as a result of an extremeflooding event and the original Safe Shutdown Earthquake (SSE) hazard curveremains bounding at 0.25g Peak Ground Acceleration.

These conclusions aredocumented in the respective APS and NRC letters (References 24 and 25).7.1. SeismicThe NEI 12-06 guidance (Reference

75) requires that all plants consider theimpact of a seismic event. As described in the PVNGS UFSAR (Reference 8,UFSAR Section 3.7), the seismic criteria include two design basis earthquake spectra:

Operating Basis Earthquake (OBE) and Safe Shutdown Earthquake (SSE). The site seismic design response spectra define the vibratory groundmotion of the SSE. For additional conservatism, FLEX permanent plantmodifications (electrical and mechanical) are designed to the SSE plus 10percent.For FLEX strategies, the earthquake is assumed and results in damage tonon-seismically designed structures and equipment.

Non-seismic structures and equipment may fail in a manner that they would challenge accomplishment of FLEX related activities (normal access to plant equipment, functionality of non-seismic plant equipment, deployment ofBeyond-Design-Basis (8DB) equipment, restoration of normal plant services, etc.). The diverse nature (e.g., alternate deployment locations, connections, and pathways, and a variety of equipment, including both electric and dieseldriven motors) of the PVNGS FLEX strategies is discussed throughout thisreport and PVNGS has the ability to clear debris from hauling routes tofacilitate the deployment of FLEX Phase 2.Page 45 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2 and 37.2. High Temperatures NEI 12-06 (Reference 75, Section 9.2) requires all plants to consider hightemperature conditions for the site in storing and deploying the FLEXequipment.

PVNGS addresses the effect of extreme heat on continued plantoperation with current administrative controls if the temperature exceedsdesign basis values.PVNGS may experience extreme high temperatures for a prolonged duration.

However, the extreme drought and high temperature meteorological eventsprogress slowly such that existing plant administrative and operational procedures are adequate to ensure that the plant is shutdown and placed in asafe condition.

The extreme heat event considered herein is a loss of AC power as a result ofhigh temperatures coincident with high electrical grid demands, resulting in aregional black out. During this type of event, the equipment conditions andwater inventories at the station are expected to be within design limits suchthat no additional limitations on initial conditions/failures/abnormalities areexpected (also see Section 2.1, assumptions 19 and 20).7.3. Not Applicable External eventsUsing guidance and screening processes provided by NEI 12-06 (Reference 75), the following external hazards are not applicable to PVNGS site.External FloodingPVNGS is a dry site (Reference 8, UFSAR Section 2.4.2.2) and does not relyon a permanently installed seawall or levee for flood protection.

Therefore, PVNGS does not need to consider external flooding as a hazard defined inNEI 12-06 (Reference 75), Section 6.2.1, and Reference 24, the PVNGS FloodHazard Reevaluation.

High WindN EI 12-06 (Reference

75) Section 7.2.1, Applicability of High Wind Conditions, contains a screening process to identify whether sites should address highwind hazards as a result of hurricanes and tornadoes.

Based upon the locationof the site at 33023'N and 112°52'W and the information provided in Figures 7-1 and 7-2 of NEI 12-06 (Reference 75), PVNGS is not expected to experience winds exceeding 130 mph. Therefore, the high wind hazard is not applicable toPVNGS.Page 46 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2and 3Ice, Snow and Extreme ColdNEI 12-06 (Reference

75) Section 8.2.1, Applicability of Snow, Ice andExtreme Cold, clarifies that snow, ice and extreme cold are not expected atsites in Southern California,

Arizona, the Gulf Coast, and Florida.

Because thesite is located in Arizona and below the 35th parallel (33°23'N),

ice, snow, andextreme cold hazard is not applicable to PVNGS.8. Protection of FLEX Equipment 8.1. FLEX Emergency Equipment Storage Facility and Deployment The FLEX Emergency Equipment Storage Facility (EESF) that housesequipment for FLEX is constructed to be seismically robust using therequirements of ASCE 7-10 (consistent with NEI 12-06, Section 5, Reference 75 and Reference 3). Trailer mounted equipment within buildings will berestrained to tie down hooks using nylon strap winches at twice the calculated load to eliminate seismic interaction.

The EESF (shown as part of Figure 18) is comprised of four individually seismically isolated buildings, a separate stand-alone climate controlled

building, and a canopy structure.

The four seismically isolated buildings houseFLEX equipment for each of the units and an additional set of "N+1"equipment.

These buildings are not temperature controlled.

The separateclimate controlled building is used for housing equipment, parts, andmiscellaneous items which are susceptible to the outside environment.

Thisclimate controlled building will also serve as the command control center forNSRC delivered equipment post event.Lastly, the canopy area has been provided as a parking location for FLEXvehicles and debris removal equipment, such as front end loader,transportation trucks and yard truck. The vehicles are parked with at least a 6foot separation to avoid seismic interaction (Reference 60). Therefore, theequipment will remain functional and deployable, to clear obstructions from thepathway between the EESF location and deployment location(s).

Deployment of the debris removal equipment and the Phase 2 FLEX equipment from theEESF is not dependent on offsite power. The building equipment doors maybe manually opened.The FLEX EESF is designed to withstand EF-3 tornado wind speeds(excluding roofing material) and the finished floor is 1 foot above the predicted site flood elevation as a result of PMP. Additionally, located directly northwest of the EESF, a seismic pad was built to aide with future facility maintenance issues, should there be a need to store equipment outside to maximize theavailability of FLEX equipment.

The seismic pad will be maintained indefinitely.

Page 47 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 3The EESF is located west of the Protected Area (PA) warehouse and is insideof the owner controlled area, but outside of the PA (see Figure 18).8.2. FLEX Deployment PadsIf equipment with safety function(s) is pre-deployed, it would be deployed in apre-designated, seismically

designed, concrete pad location and restrained in8 directions to tie-down anchors.

These locations are evaluated for seismicinteraction with non-seismic SS0s (see Figure 19 for location deployment locations) and at least one staging location for each strategy is free of seismicinteraction.

9. Planned Deployment of FLEX Equipment 9.1. Deployment RoutesFigure 20 shows the paths for transportation of FLEX equipment todeployment areas. The deployment routes within PVNGS are engineered roads. They were evaluated for the seismic interaction and soil liquefaction hazards and determined to remain passable following a seismic event(Reference 61). Deployment routes are surveyed following an event and anappropriate route will be selected.

An administrative program (Reference

65) isin place to maintain the routes clear during normal site activities in all modes ofplant operation.

9.2. Accessibility

The potential impairments to required access are: 1) doors and gates, and 2)site debris blocking personnel or equipment access. The coping strategy tomaintain site accessibility through doors and gates is applicable to all phasesof the FLEX coping str'ategies, but is essential as part of the immediate activities required during Phase 1.Doors and gates serve a variety of barrier functions on the site. One primaryfunction,

security, is discussed below. However, other barrier functions includefire, flood, radiation, ventilation,

tornado, and high energy line breaks (HELB).These doors and gates are typically administratively controlled to maintaintheir function as barriers during normal operations.

Following a BDBEE andsubsequent ELAP event, FLEX coping strategies only require operator walk-downs for damage assessment at PVNGS, no routing of hoses and cablesthrough barriers are required to achieve established FSG strategies.

However, ability to open doors for ingress, egress, and ventilation isnecessary.

Security doors and gates that rely on electric power to operateopening and/or locking mechanisms are barriers of concern.

The SecurityPage 48 of 1O00 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 3force will initiate an access contingency upon loss of the Security Diesel andall AC/DC power as part of the Security Plan. Access to the Owner Controlled Area, site Protected Area, and areas within the plant structures will becontrolled under this access contingency as implemented by Securitypersonnel.

Access authorization lists are prepared daily and copies areprotected from the BDBEE for use post-ELAP.

The plant main control roomcontains a duplicate set of security keys for use by plant Operations personnel in implementing the FLEX strategies.

Vehicle access to the Protected Area is via the double gated sally-port at theSecurity Building.

As part of the Security access contingency, the sally-port gates will be manually controlled to allow delivery of BDB equipment (e.g.,generators, pumps) and other vehicles such as debris removal equipment intothe Protected Area.9.3. On-Site Fuel Storage Tanks and Qualifications During Phase 2, unit essential diesel generator fuel oil seismically qualified day tanks in each diesel building are used for initial fueling of FLEX dieselpowered makeup pumps and 480 VAC 800 kW generators.

These essential tanks (one per train, two per Unit) have a capacity of 1,100 gallons.

The drainportion of this tank has been permanently modified (see Section 4.4) toprovide a gravity drain at ground elevation, such that a self-contained 500gallon fuel trailer (2 available on site) can be filled with no AC power available.

These fuel oil tank trailers will provide sufficient fuel to SEP makeup pumpsand 480 VAC 800 kW generators to start. Once the 480 VAC 800 kWgenerators are started, the essential fuel oil transfer pumps are powered andfuel oil can be delivered continuously from the 7-day underground seismically qualified tanks (nominal capacity is 83,000 gallons per tank) to the essential day tanks for distribution to the diesel driven engines on portable FLEXequipment and vehicles.

A procedure is developed to ensure fueling strategies are successful (Reference 72).10. DePloyment of Major FLEX Equipment and Strategies 10.1. Reactor Core Cooling and Heat Removal Equipment Deployment andAssociated Water Inventory SourcesThe Condensate Storage Tank (CST) and Reactor Makeup Water Tank(RMWT) provide primary sources of water to the essential Turbine DrivenAuxiliary Feedwater (TDAFVV) pump or directly to the suction of the portablediesel driven FLEX SG makeup pump. Additionally, the seismic category I,Refueling Water Tank (RVVT) could be used as a source of inventory.

Usingthis source of water would require a portable pump and hoses between RWTand CST.Page 49 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2 and 3Two FLEX suction connections (5-inch STORZ) are provided at easy toaccess locations, one at the external wall of condensate tank pump house andsecond at drain connection to CST. A flexible hose will be routed from thepump suction to the water source.Both of the FLEX SG makeup pump discharge connections also are located atthe Condensate Pump House, external to the MSSS building.

Figure 19 depicts deployment pad location of the SG makeup pump andFigure 21 depicts the approximate location of the primary and alternate

suction, the flow path, and equipment utilized to facilitate this FLEX strategy.

Two egress/ingress paths are available to the essential TDAFW pumpcompartment (train A). Access can be achieved using the 80 ft. qualified watertight door or through an access hatch at the 100 ft. elevation of the MSSSbuilding.

As stated in Section 4.3, the entrance door also provides a ventilation path to control the environment temperature within the essential TDAFW pumpcompartment.

Should the door at 80 ft. not be operational or blocked by debrisor water accumulation as a result of non-seismic turbine building structures and/or systems failure, the FLEX installed hatch at the 100 ft. elevation of theMSSS can be also used for ventilation and access (see Section 4.4).The FLEX SG boundary valves (interface between Q1E and ASME B31.1piping),

interconnecting the FLEX modification to the plant permanent AFWsystem, are located in the electric motor driven AFW pump compartment (trainB) (Figure 21). Access to this location is via the existing hatch at the 100 ft.elevation.

Both hatch openings are equipped with access ladders.10.2. RCS Injection Skid Deployment and Associated Water Inventory SourcesThe primary RCS pump deployment and connection is located plant southwest of the fuel building, adjacent to the RWT. This location includes a 5-inchSTORZ fitting for low pressure, high flow deployment during modes 5 & 6 anda 1 1/2/ inch NPT threaded connection for high pressure injection duringoperational modes. To power the high pressure electric motor driven ROSinjection pump, redundant Class 1 E train essential 480 V receptacles are alsoat this location, in the yard area and easily accessible after any externalevents. The suction source for RCS injection and makeup is the RVVT. Thedrain of the RWT was modified at ground elevation with a 5-inch STORZ fittingto provide easy access to attach the suction for these pumps.An alternate location for the high pressure RCS injection pump is within theauxiliary building entrance east west corridor at ground elevation.

This areawas selected due to ease of access via the large rollup door which opens tothe outside.

Access is credited for LOCA portable hydrogen recombiner deployment.

This location is equipped with an identical set of electrical andPage 50 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2 and 3mechanical equipment/connections as described above for the primarylocation;

however, no tie downs are provided at this location since this locationwill not be used for pre-staging.

Suction for the alternate location is established at the suction to the permanent essential charging pump in the chemical andvolume control system (CVCS). Refer to Figure 22 for primary deployment location arraignment using the electric motor driven ROS injection pump andFigure 23 for the alternate deployment location arrangement.

After deployment of the FLEX RCS pump, an operator needs to access theauxiliary

building, east or west mechanical penetration room at 70 ft. elevation, to open FLEX to high pressure safety injection (HPSI) boundary valves(interface between Q1 E: and ASME B31 .1 piping).

Additionally, during a Modes1 -4 FLEX event, operator action is also needed to access the auxiliary building 120 ft. west or 100 ft. (ground) east electrical penetration rooms toalign the disconnect switches to FLEX power source aligned to A or B, Class1 E train of the essential 480 VAC system (see Figure 3 and Figure 9).10.3. SFP Makeup Pump Deployment and Associated Water Inventory SourcesThe SFP makeup strategy will initiate makeup by deploying the FLEX dieseldriven SFP makeup pump at a pre-designated pad (Figure 19). The discharge and suction of the SFP makeup pump will be connected to 5-inch STORZconnection.

The primary discharge is located outside of the fuel building.

Thealternate location for discharge is just inside the fuel building, adjacent to therollup door.The FLEX SFP makeup pump suction will be attached to RVVT, if the initiating event occurs during operational modes, as shown in Figure 22. Since RVWTinventory is not available to be used for SFP makeup during a lower modeFLEX event, the CST primary FLEX drain connection will be used as primarysource of makeup if the initiating event occurs during an outage.Makeup to the SFP will be coordinated between a local and control room staff.Using the newly installed SFP level instrumentation (Reference

23) the pool isbatch filled to a nominal level and then it will be cooled by boil off to anelevation 10 ft. above active fuel. This process will allow multiple suctionsources (RCS injection and SFP makeup) from a single drain of the RVVT.10.4. FLEX 480 VAC Electrical Generator Deployment In phase 2, or as part of pre-outage deployment, two 480 VAC 800 kWgenerators will be moved onto a pre-designated seismically qualified padsouth of each unit (approximately 200 ft. from receptors).

The generators maybe connected to external primary or alternate receptacle connection boxes(see Figure 24). After the generators sets are connected, isolation breakerscan be closed and loads added, as required by the FSGs. Isolation breakersPage 51 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 3are located at the ground elevation of the control building, and are easilyaccessible from the deployment location or control room.Each 480 VAC 800 kW diesel driven generator set is equipped with a set ofcolor coded cables which connect from the deployed generators to a panellocated in the south yard as shown in Figure 24. A cable set consists of 2 x 3 x250 MOM -100 ft. cables per phase, plus two grounds,

neutral, and spare.100 ft. segments of cables are stored on easy to move carts. Two individual trailers house the cables for these generators.

Each cable is color coded perNSRC standard.

Wall mounted receptacles are also color coded and verifiedas part of design modification configuration for conductivity and phase rotation.

For each 1 E cabinet, a new 600 amp breaker is installed.

These breakers arelocked in the open position and proceduralized to provide isolation betweenthe 1E and non1E circuits.

10.5. Defense-in-Depth 4.16 kV 4 MW Electrical Generator Deployment Medium voltage Defense-in-depth generators provide the station with vastflexibility to mitigate an unexpected event. Although not credited (or required) for FLEX, a combination of plant modification and onsite availability of 4 MWe,at 4.16 kV, adds a significant safety margin to overall FLEX philosophy.

The 2X 2 MWe generator set is stored in the FLEX EESF (an additional 8 MWe canbe supplied by NSRC) and is sufficient for supply power to one train of theUHS for events that would not result in damage to the seismically designedPVNGS redundant spray ponds, such as an extreme heat event.Operationally, initiating shutdown and spent fuel pool cooling and by usingthese generators, early in the event, will eliminate the need for a significant amount of Phase 2 FLEX equipment and manpower.

Defense-in-depth 4.16 kV AC generators can be moved onto pre-designated seismic pad south of each unit (approximately 200 ft. from switch gearreceptacle boxes) and they can be connected to external primary or alternate switch gear receptacle boxes (see Figure 24). After generators sets areconnected, Isolation switch can be closed and loads can be added as requiredby FSGs. 4.16 kV seismically qualified isolation manual switches are locatedat the ground elevation of the control building, and are easy to access fromgenerator pad location Or unit control room. Two (2) sets of cables plus spareper unit (total 6) are available in easy to deploy trailers with diesel driven cabledeployment mechanism.

10.6. Fueling of Equipment All non-electric driven FLEX equipment, including vehicles and debris removalequipment and FLEX supporting

machines, have their motive force poweredby low sulfur diesel fuel oil. Two (2) 500 gallon mounted fuel tanker trailers andPage 52 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 3two (2) fuel delivery systems using diesel fuel tank trailers and trucks will beused to fuel each unit's FLEX equipment, as needed, with high priority given toFLEX equipment that provides critical safety functions.

Once deployed duringan ELAP BDBEE, a fuel transfer trailer will refuel equipment per aproceduralized

sequence, as required (Reference 72). Site fuel capacity andsources are described in Section 9 of this report. The NSRC and external stateand national resources will provide diesel fuel oil once site inventory isexhausted.

All vehicles and debris removal equipment will be maintained with sufficient fuel to achieve initial implementation of the 480 VAC generators so they canprovide motive force for fuel distribution (see Section 9.3).11. Offsite Resources 11.1. National SAFER Response CenterThe industry has established two (2) National Strategic Alliance for FLEXEmergency Response (SAFER) Response Centers (NSRCs) to supportutilities during BDB events and these resources have been accepted by theUSNRC (Reference 28). APS, the operator of PVNGS, has established contracts with the Pooled Equipment Inventory Company (PEICo) toparticipate in the process for support of the NSRCs as required.

Each NSRCwill hold five (5) sets of equipment, four (4) of which will be able to be fullydeployed when requested, the fifth set will have equipment in a maintenance cycle. In addition, onsite BDB equipment hose and cable end fittings arestandardized with the equipment supplied from the NSRC.In the event of a BDBEE and subsequent ELAP condition, equipment will bemoved from an NSRC to a local staging area "C" established by the SAFERteam. For the PVNGS, the NSRC-Phoenix is designated as staging area "C".From there, equipment can be taken to the PVNGS site and staged at theonsite Staging Area near the FLEX EESF and close to helicopter pad (seeFigure 18), or by helicopter if ground transportation routes are unavailable.

Twenty four (24) hours after notification the first piece of offsite equipment isdelivered to the onsite staging area. The equipment is delivered as identified inthe PVNGS SAFER Response Plan (Reference 62).12. Equipment ListTable 2, Table 3, and Table 4 provide a summary overview of the types andquantities of equipment needed to support the PVNGS FLEX integrated plan.Equipment selection considered NEI 12-06 (Reference 75), Sections 9.3.2 and9.3.3 recommendations.

Page 53 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 3Specifications for FLEX equipment include applicable environmental parameters.

The FLEX equipment required to provide safety functions are procured forcontinuous operation at a limiting extreme temperature of 130 *degrees F.The equipment stored and maintained at the NSRC for transportation to supportphase 3 of ELAP strategies are listed in the PVNGS SAFER Response Plan(Reference 62).13. Habitability and Operations 13.1. Equipment Operating Conditions As described previously in this report, a minimum set of instrumentation hasbeen selected to provide control room operators with key safety-function information.

Instruments identified are safety related, seismically qualified, meet the environmental qualification requirements of 10 CFR 50.49, and areverified qualified Consistent with the criteria in NEI 12-06, Section 3.2.1.12(Reference 75). The PVNGS ELAP analysis does not credit automatic actuation beyond the SBO scenarios, and such actions would occur within thefirst hour of the event. The SBO response strategies were reviewed andapproved by the NRC in Reference

21. Operator actions directed by the FSGsare manual actions after the first hour. Instrumentation and components credited are qualified to 10 CFR 50.49 for loss of coolant accident (LOCA) andsteam line break; therefore, they will remain accurate and reliable for theduration of the beyond-design-bases event. Additionally, the maximumtemperature expected within containment during an ELAP remains below thethreshold of the equipment qualification harsh limit of 230 degrees F.Additional extensive analysis was performed to evaluate the essential TDAFW*compartment and it was concluded that the system will not be adversely impacted if the access door or hatch is opened at about 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months , refer toSection 4.3 and discussion in Section 2 on analytical methods.13.2. Personnel Habitability Long term habitability will be assured by monitoring control room conditions, heat stress countermeasures, and rotation of personnel to the extent feasible.

PVNGS procedure "Heat Stress Prevention Program" (Reference

64) outlinesthe issues and the actions to take when working in a higher temperature environment and provides various measures to mitigate the effects of workingin elevated temperatures for extended periods.The control room staff is trained on the expected conditions, the need for selfand team monitoring, and the countermeasures available.

The staffinganalysis (see Section 13.6 of this report) addresses the availability ofreplacement personnel, both long term and in the event of medical emergency.

Page 54 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2 and 3The Control Room Envelope (CRE) was analyzed using simplified a GOTHICcomputer code model and it was concluded that the CRE will not exceed 115degrees F.All others portions of the plant that may require personnel entry will remainhabitable at times when, strategies necessitate operator actions.

Duringpreliminary walk-downs, it is possible that non-seismic SSC failure within thesafety related buildings, such as the Auxiliary and MSSS buildings, mayimpede the normal access paths. Alternative egress/ingress pathways areavailable at each structure.

Internal flooding as a result of seismic failure ofnon-quality systems is not a concern since areas that require access willremain above the most limiting flood levels. Although there is a possibility ofsteam leakage from the Auxiliary Steam System within the auxiliary and MSSSbuildings, the source of steam is quickly eliminated once Main Steam Isolation occurs as result of reactor trip and AFW actuation.

The buildings will. return toambient conditions within a few hours and before access is required for FLEXimplementation.

PVNGS fuel building is vented by opening the large rollupdoor and, although no operator action is required within the building as tocomply with NRC Order EA-12-051 (Reference 2), ventilation will aid to coolthe lower elevation building should entry be needed.13.3. LightingPVNGS emergency lighting is described in UFSAR Sections 9.5.3.2.2.3 (Reference 8). In the control room emergency lighting is designed to providesufficient illumination for the operator to perform the required actions in theevent of a loss of essential power. The emergency lighting system hasminimum of eight hour battery-backed power. It is expected that the powersource for these batteries will realistically provide illumination for a longerduration.

This lighting illuminates automatically upon a loss of AC power. The Train "A"essential lighting is powered by the FLEX 480 VAC, 800 kW generators toprovided illumination for FSGs critical operator actions.

Diesel driven.temporary FLEX equipment (pumps and generator) are designed to have self-illumination and will not require an external source.Should emergency lighting fail, the standard gear/equipment for operators includes flashlights and portable lanterns and light stands (Reference 68).13.4. Communications Communications strategies, following the guidelines of NEI 12-01 (Reference 74), for BDBEE are described in the PVNGS response to NRC 50.54(f) letteron NTTF 9.3 (Reference 4 and Reference

29) and NRC acceptance documented in Reference 30.Page 55 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2and 313.5. Additional Water SourcesFSG strategy long term sources of water after 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months are provided by twostate certified, seismically

designed, below ground reservoirs with a minimum500 million gallon capacity.

These reservoirs normally supply cooling water tothe cooling towers and are described section of 2.4.8.2.2 of the PVNGSUFSAR (Reference 8). This water will be available at each unit before otherwater sources are exhausted (refer to Section 4.3 of this report).

Theequipment and components for the delivery system to the units are stored insecure shelters strategically placed along the path of the pipe line for ease ofimplementation.

This equipment, in addition to complementary equipment provided by NSRC for phase 3, will provide sufficient water to continue copingstrategies indefinitely.

13.6. StaffingStaffing strategies, following the guidelines of NEI 12-01 (Reference 74), forBDBEE are described in the PVNGS response to NRC 50,54(f) letter on NTTF9.3 (Reference 4 and Reference

10) and NRC acceptance documented inReference 31.Human resources begin arriving at the Palo Verde site starting at six hoursafter the event occurs (Reference 80). The Palo Verde site is fully staffed by24 hours (Reference 10).14. Sequence of EventsThe Sequence of Events Timeline for an ELAP as a result of a BDBEE atPVNGS is presented in Table 5.No sequence of events is provided for the lower modes since plant condition andavailability of S50s are variable.

Per NEI Guidance (Reference

18) shutdownrisk assessment will be performed for each outage and evaluate if lower modeFSG (Reference

69) strategies are implementable or additional action is need.Strategies for lower modes are discussed in Sections 4.2, 5, and 6.2 of thisreport.Validation of each of the FLEX time constraint actions has been completed inaccordance with NEI 14-01 (Reference

93) and includes consideration forstaffing.

Page 56 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 315. Programmatic Elements15.1. Overall Program DocumentThe Palo Verde Nuclear Generating Station Diverse and Flexible CopingStrategies (FLEX) Program Plan (Reference

65) is implemented to comply*with the requirement of the Nuclear Regulatory Commission Order EA-12-049 (Reference

2) and NE1 12-06 (Reference 75), which states:"The FLEX strategies and basis will be maintained in an overallprogram document.

This program document will also contain ahistorical record of previous strategies and the basis for changes.The document will also contain the basis for the ongoingmaintenance and testing programs chosen for the FLEXequipment."

The key elements of the program include:* Maintenance of the FSGs including impacts on the interfacing procedures (EOPs, Abnormal Operating Procedures (AOPs), SevereAccident Mitigation Guidelines (SAMGs),

or Extreme DamageMitigation Guidelines (EDMGs),

etc.)* Maintenance and testing of FLEX equipment (i.e., SFP levelinstrumentation, emergency communications equipment, portableFLEX equipment, FLEX support equipment, and FLEX supportvehicles)

Portable equipment deployment routes, Staging areas, andconnections to existing mechanical and electrical systems* Validation of time sensitive operator actions* The FLEX EESF and the NSRC* Hazards Considerations (See Section 7)* Supporting evaluations, calculations and drawings* Tracking of commitments and equipment unavailability

Staffing,

Training, and Emergency Drills* Configuration Management

Program Maintenance Page 57 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2and 3The instructions required to implement the various elements of the FLEXProgram and thereby ensure readiness in the event of a BDBEE are contained in station procedures.

Existing design control and fuel cycle procedures have been revised to ensurethat changes to the plant design, physical plant layout, roads, buildings, andmiscellaneous structures will not adversely impact the approved FLEXstrategies.

Changes for the FLEX strategies will be reviewed with respect tooperations critical documents to ensure no adverse effect.Limited configuration and quality assurance control for portable equipment supporting the FLEX coping safety function is implemented.

Only documents establishing performance basis for critical safety function which are used asthe basis for maintenance testing will be maintained in the PVNGS documentcontrol system. These include engineering and manufacturing reportsestablishing critical attribute for tests recommended by EPRI (Reference 94and Reference 20).Future changes to the FLEX strategies may be made without prior NRCapproval provided

1) the revised FLEX strategies meet the requirements ofNEI 12-06 (Reference

75) and supporting documents, and 2) an engineering basis is documented that ensures that the change in FLEX strategies continues to ensure the key safety functions (core and SFP cooling,Containment integrity) are met.15.2. Procedural GuidanceThe inability to predict actual plant conditions that require the use of FLEXequipment makes it impossible to provide specific procedural guidance.

Assuch, the FSGs (Reference 68 and Reference

69) provide guidance that canbe employed for a variety of conditions.

The FSGs have been developed in accordance with plant specific analysis andindustry guidance accepted by the NRC. FLEX Support Guidelines provideavailable, pre-planned FLEX strategies.

FSGs will be used to supplement (notreplace) the existing procedure structure that establishes command andcontrol for the event.Procedural Interfaces have been incorporated into exiting procedures such as"Blackout" (Reference

66) to the extent necessary to include appropriate reference to FSGs and provide command and control for the BDBEE ELAP.FSG updates will be performed as necessary; site administrative processes, NEI 96-07 (Reference 79), and NEI 97-04 (Reference

95) are used to evaluatechanges to procedures.

Page 58 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2 and 3FSGs are reviewed and validated by the site stakeholders to the extentpossible and practical to ensure the strategies are implementable.

Validation isaccomplished by use of desktop discussion, simulator practices, walk-throughs, hands-on simulation of implementation, and drills.FLEX mitigation equipment is subject to initial acceptance testing andsubsequent periodic maintenance and testing to verify proper function (SeeSection 15.5).15.3. Organizational responsibilities The following is a description of the roles and responsibilities of thoseassociated with the FLEX Program:FLEX Program Owner -The Program Owner has the following responsibilities:

Coordination of overall station BDBEE strategies and trending the healthof the program.* Compliance with regulatory requirements

Maintenance of program manual* Maintain operational margin* SAFER Site Specific response planDepartment Leader. Fire Protection

-The Fire Protection Department has thefollowing responsibilities:

Development of FLEX equipment surveillance and maintenance procedures

Surveillance/Maintenance Of Fire Department FLEX equipment

Equipment Inventory

FLEX equipment deployment Incident Command* Training of Fire Department personnel on the aspects of the FLEXprogramPage 59 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2and 3Department Leader. Operations

-The Operations Department has thefollowing responsibilities:

Overall responsibility of the management and direction of the PVNGSpost-Fukushima response* Implementing the operational strategies as required during a BDB event.* Coordinating the activities of on-site affected departmental

entities, as wellas communication with nuclear industry counterparts for information sharing* Training of Operations personnel on the aspects of the FLEX programDepartment Leader. Site Procedure Standards

-The Procedure Standards Department is responsible for the revision of operational and administrative procedures that interface with the FLEX program.Managqer, Emergencv Preparedness

-Emergency Preparedness has thefollowing responsibilities:

FLEX Program site drills and exercise planning/implementation 15.4. TrainingThe PVNGS Nuclear Training Program is updated to include training on themitigation of BDB external events. These programs and controls aredeveloped and have been implemented in accordance with the Systematic Approach to Training (SAT) process.Initial training has been provided and periodic training will be provided to siteemergency response leaders on FLEX emergency response strategies andimplementing guidelines.

Personnel assigned to direct the execution ofmitigation strategies for 8DB external events have received the necessary training to ensure familiarity with the associated tasks, considering available job aids, instructions, and mitigating strategy time constraints.

Care has been taken to not give undue weight (in comparison with othertraining requirements) for operator training for FLEX external event accidentmitigation.

The testing/evaluation of operator knowledge and skills in this areahave been similarly weighted.

Where appropriate, integrated FLEX drills will be organized on a team or crewbasis and conducted periodically, with time-sensitive actions to be evaluated over a period of not more than eight years. It is not required to connect/operate permanently installed equipment during these drills.Page 60 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2 and 315.5. Equipment Maintenance and TestingPeriodic testing and preventative maintenance of the FLEX equipment conforms to the guidance provided in the Institute of Nuclear PowerOperations' AP-91 3 (Reference 96). Site procedures have been developed toaddress preventative maintenance (PM) using the Electric Power ResearchInstitute (EPRI) templates manufacturer providedinformation/recommendations, and equipment testing criteria.

Using the EPRI Preventive Maintenance guidance (Reference 94),Preventative Maintenance (PM) tasks are issued for major FLEX equipment including the portable diesel and electric motor driven pumps and generators.

The PM Templates include activities such as:* Periodic static inspections

-Monthly walk-down

Periodic operational verifications

-Quarterly starts* Periodic functional verifications with performance tests -Annual 1 hourrun with pump flow and head verifications The unavailability of equipment and applicable connections that directlyperform a FLEX mitigation strategy for core cooling, containment integrity, andSEP cooling will be managed such that risk to mitigating strategy capability isminimized by using the following guidance:

Portable FLEX equipment or a portion of the FLEX Emergency Equipment Storage Facility (EESF) may be unavailable for 90 days provided that thesite FLEX capability (N) is available.

If portable equipment or a portion of the FLEX EESF becomes unavailable such that the site FLEX capability (N) is not maintained, actions will beinitiated within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months to restore the site FLEX capability (N) andimplement compensatory measures (e.g., use of alternate suitableequipment or supplemental personnel) within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .Work Management procedures are revised to reflect allowed outage times asoutlined above.Page 61 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2 and 3References Regulatory

1. SECY-1 1-0093, "Near-Term Report and Recommendations for Agency ActionsFollowing the Events in Japan," July 12, 2011. [Agencywide Documents Access andManagement System (ADAMS) Accession Number ML11186A950]

2. NRC Order EA-1 2-049, "Issuance of Order to Modify Licenses with Regard toRequirements for Mitigation Strategies for Beyond-Design-Basis External Events,"March 12, 2012. [ADAMS Accession Number ML12056A045]

See also, NRC OrderEA-1 2-051, "Issuance of Order to Modify Licenses with Regard to Reliable SpentFuel Pool Instrumentation,"

March 12, 2012. [ADAMS Accession NumberM LI 2054A679]

3. NRC Interim Staff Guidance JLD-ISG-2012-01, Revision 0, "Compliance with OrderEA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events,"

August 29, 2012. [ADAMSAccession Number ML1 2229A1 74]4. NRC Letter to APS, "Request for Information Pursuant to Title 10 of the Code ofFederal Regulations 50.54(f),

Regarding Recommendations 2.1, 2.3, and 9.3 of theNear-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident,"

March 12, 2012. [ADAMS Accession Number ML12053A340]

5. NRC Letter to APS, "Palo Verde Nuclear Generating

Station, Units 1, 2, and 3Interim Staff Evaluation Relating To Overall Integrated Plan In Response To OrderEA-12-049

-Mitigation Strategies,"

November 25, 2013. [ADAMS Accession NumberML1 3308C1 53]6. NRC Letter to APS, "Palo Verde Nuclear Generating

Station, Units 1, 2, and 3Report For The Audit Regarding Implementation Of Mitigating Strategies AndReliable Spent Fuel Pool Instrumentation Related To Orders EA-12-049 And EA-12-051 ," September 8, 2014. [ADAMS Accession Number ML14239A181]

7. NRC Internal Memorandum, From Jack R. Davis, "Supplemental Staff Guidance forthe Safety Evaluations for Order EA-12-049 on Mitigation Strategies forBeyond-Design-Basis External Events and Order EA-12-051 on Spent Fuel PoolInstrumentation,"

July 1,2014.8. "Palo Verde Nuclear Generating Station Units 1, 2, and 3 Updated Final SafetyAnalysis Report (UFSAR),"

Revision 18, June 2015.9. APS Letter 102-06670, "APS Overall Integrated Plan in Response to March 12, 2012Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order EA-12-049),"

February28, 2012. [ADAMS Accession Number ML13136A022]

See also, APS Letter 102-06669, "APS Overall Integrated Plan in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Reliable Spent Fuel Pool LevelPage 62 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 3Instrumentation (Order Number EA-12-051),"

February 28, 2013.10.APS Letter 102-06885, "Palo Verde Nuclear Generating Station (PVNGS) Units 1,2,and 3 Docket Nos. STN 50-528, 50-529, and 50-530 Submittal of Phase 2 StaffingAssessment Report,"

June 11, 2014.11 .APS Letter 102-06733, "Palo Verde Nuclear Generating Station (PVNGS) Units 1, 2,and 3, Docket Nos. STN 50-528, 50-529, and 50-530, Response to Request forAdditional Information for the PVNGS Overall Integrated Plan in Response to theMarch 12, 2012 Commission Order Modifying Licenses with Regard toRequirements for Mitigation Strategies for Beyond-Design-Basis External Events(Order Number EA-12-049),"

July 18, 2013. (Confidential) 12.APS Letter 102-06985, "Palo Verde Nuclear Generating Station (PVNGS) Unit 1Docket No. STN 50-528 Notification of Full Compliance with NRC Orders EA-12-049 and EA-12-051 for PVNGS Unit 1," January 09, 2015. [ADAMS Accession NumberML1 501 2A444]13.APS Letter 102-07048, "Palo Verde Nuclear Generating Station (PVNGS) Unit 3Docket No. STN 50-530 Notification of Full Compliance with NRC Orders EA-12-049 and EA-12-051 for PVNGS Unit 3," May 26, 2015. [ADAMS Accession NumberML1 51 49A020]14.APS Letter 102-071 57, "Palo Verde NUclear Generating Station (PVNGS) Units 1, 2and 3, "Notification of Full Compliance with NRC Orders EA-12-049 and EA-12-051 for PVNGS Units 1,2 and 3," December 17, 2015.15. Task Interface Agreement (TIA) 2004-04, "Acceptability of Proceduralized Departures from Technical Specifications (TSs) Requirements at the Surry PowerStation,"

(TAC Nos. MC4331 and MC4332),"

September 12, 2006. [ADAMSAccession Number ML060590273]

16. NRC Letter to NEI, "Endorsement of FLEX Generic Open Item for Use ofCombustion Engineering Nuclear Transient Simulation (CENTS) Code for theExtended Loss of AC Power (ELAP) Event," October 7, 2013. [ADAMS Accession Number ML1 3276A555]

17. NRC Letter to NEI, "Endorsement of FLEX Generic Open Item EA-12-049 Mitigating Strategies Resolution of Extended Battery Duty Cycles Generic Concern withExceptions,"

September 16, 201 3. [ADAMS Accession Number MLI13241A1 88]18. NRC Letter to NEI, "Endorsement of FLEX Generic Open Item EA-12-049 Mitigating

.Strategies Resolution of Shutdown/

Refueling Modes," September 30, 2013. [ADAMSAccession Number ML1 3267A382]

19. NRC Letter to Westinghouse, "Endorsement of FLEX Generic Open Item EA-12-049 Mitigating Strategies, Westinghouse Response to NRC Generic Request forAdditional Information (RAI) on Boron Mixing in Support of the Pressurized WaterReactor Owners Group (PWROG) with Exceptions,"

January 8, 2014. [ADAMSAccession Number ML1 3276A1 83]Page 63 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2 and 320. NRC Letter to EPRI, "Endorsement of FLEX Generic Open Item EA-12-049 Mitigating Strategies, Nuclear Maintenance Applications Center: Preventive Maintenance Basisfor FLEX Equipment,"

October 7, 2013. [ADAMS Accession Number ML13276A224]

21 .NRC Letter to APS, "Revised Station Blackout Coping Duration,"

October 31, 2006.[ADAMS Accession Number ML06291 0280]22. NRC Branch Technical Position APCSB 9-2, "Residual Decay Energy for LightWater Reactors for Long Term Cooling,"

July 1981.23. APS Letter 102-06669, "APS Overall Integrated Plan in Response to March 12, 2012Commission Order Modifying Licenses with Regard to Reliable Spent Fuel PoolLevel Instrumentation (Order Number EA-12-051),"

February 28, 2013. [ADAMSAccession Number ML13070A077]

24. NRC Letter to APS, "Palo Verde Nuclear Generating

Station, Units 1, 2 and 3 -Correction to Interim Staff Response to Reevaluated Flood Hazards Submitted inResponse to 10 CFR 50.54(f)

Information Request -Flood-Causing Mechanism Reevaluation,"

October 8, 2015. [ADAMS Accession Number ML15280A022]

Seealso APS Letter 102-06997, "Flood Hazard Reevaluation Report,"

dated December12, 2014 (ADAMS Accession No. ML14350A466]

25. NRC Letter to APS, "Final Determination of Licensee Seismic Probabilistic RiskAssessments under the Request for Information Pursuant to Title 10 of the Code ofFederal Regulations 50.54(f)

Regarding Recommendation 2.1 Seismic of theNear-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident,"

October 27, 2015. [ADAMS Accession Number ML15194A015]

See also, APSLetter, 102-0701 0, "Seismic Hazard and Screening Report",

March 10, 2015 andAPS Letter 102-07027, "Supplemental Information Regarding the PVNGS SeismicDesign and Licensing Basis," April 10, 2015.26. NRC Regulatory Guide 1.13, "Spent Fuel Storage Facility Design Basis," Revision 0.27. NRC Letter to Westinghouse, "NRC Endorsement of Boron Mixing in Support ofPWROG," January 8, 2014. [ADAMS Accession Number ML1 3276A1 83]28. NRC Letter to NEI, "Staff Assessment of National Safer Response CentersEstablished In Response To Order EA-12-049,"

September 26, 2014. [ADAMSAccession N umber M L14265A1 07129.APS Letter 102-06664, "APS Response to NRC Follow-up Letter on Technical Issues for Resolution Regarding Licensee Communication Submittals Associated with Near-Term Task Force Recommendation 9.3," February 22, 2013. [ADAMSAccession N umber M L13063A034]

30. NRC Letter to APS, "Palo Verde Nuclear Generating

Station, Units 1, 2, and 3 StaffAssessment In Response To Request For Information Pursuant To 10 CFR 50.54(f)-Recommendation 9.3 Communications Assessment,"

June 6, 2013. [ADAMSAccession Number M L13149A055]

Page 64 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units1, 2 and 331. NRC Letter to APS, "Response Regarding Licensee Phase 2 Staffing Submittals Associated With Near-Term Task Force Recommendation 9.3 Related to theFukushima Dai-lchi Nuclear Power Plant Accident,"

September 29, 2014. [ADAMSAccession N umber M L14262A296]

32. NRC letter to APS, "Palo Verde Nuclear Generating

Station, Units 1, 2, And 3 -Conforming License Amendments To Incorporate The Mitigation Strategies Required by Section B.5.b. of Commission Order EA-02-026 (TAC NOS. MD4552,MD4553, AND MD4554),"

August 2, 2007. [ADAMS Accession NumberM L0721 10440]APS Documents

33. PVNGS Document NM1 000-A00001, "Palo Verde Turbine Driven AFW Pump RoomHeat Up Analysis for an External Loss of AC Power"~34. PVNGS Document NM1000-A00002, "Palo Verde Units 1,2 & 3 Beyond DesignBases Event -Extended Loss of AC Power"35. PVNGS Document NM1000-A00004, "Palo Verde Units Best-Estimate Decay Heatfor Extended Loss-of-AC Power"~36. PVNGS Document NM1000-A00010, "Determination of the Time to Boil in the PaloVerde Spent Fuel Pools after an Earthquake"

37. PVNGS Document NM1000-A00015, "Electric Powered Positive Displacement Pumps Specification (APS FLEX)"38. PVNGS Document N M1000-A000 16, "Diesel Powered Centrifugal PumpsSpecification (APS FLEX)"39. PVNGS Document NM1000-A00020, "APS Palo Verde Nuclear Generating StationDetailed FLEX AFT Fathom Models"40. PVNGS Document NMI000-A00022, "480 Volt Generator (APS FLEX)"41. PVNGS Document NM1000-A00021, "480V Cable Assemblies (FLEX)"42. PVNGS Document NM1000-A00032, "Spent Fuel Pool Cooling FLEX Pump NPSHAvailability"

43. PVNGS Document NM1000-A00035, "Palo Verde Units 1, 2 and 3 Reactor CoolantSystem (RCS) Inventory, Shutdown Margin, and Mode 5/6 Boric Acid Precipitation Control (BAPC) Analyses to Support the Diverse and Flexible Coping Strategy(FLEX)"44. PVNGS Document NM1000-A00042, "Palo Verde Long Term Containment Response Following an Extended Loss of AC Power"'45. PVNGS Document NM1000-A001 16, "Palo Verde Containment Refuel Pool Time toBoil GOTHIC Evaluation from an Extended Loss of AC Power (ELAP)"46. PVNGS Document NM1000-A00174, "Palo Verde FLEX -Load Flow & MotorStarting Calculation

-480V Train 'A"'"Page 65 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 347. PVNGS Document NM1000-A00176, "Palo Verde FLEX -Load Flow & MotorStarting Calculation

-480V Train 'B"'"48. PVNGS Document NMI000-A00175, "Palo Verde FLEX -Short Circuit, Arc FlashHazard & Protective Device Coordination

-480V Train 'A"'"49. PVNGS Document NM1000-A00177, "Palo Verde FLEX -Short Circuit, Arc FlashHazard & Protective Device Coordination

-480V Train 'B"'"50. PVNGS Document NMI000-A00048, "Load Shed -Battery Discharge CapacityAnalysis"

51. PVNGS Document NM1000-A001 26, "Seismic Margin Assessment:

Evaluation ofSeismic Margins of the Reactor Make-up Water"52. Calculation I13-JC-CH-0209, "Refueling Water Tank Level Measurement"

53. PVNGS Document NM1000-A00006, "Seismic Fragility Analysis of NQR PipingConnected to Condensate Storage Tank"54. Calculation 13-JC-CH-0214, "Reactor Makeup Water Tank Level Instrument (CHN-L-210)

Setpoint and Uncertainty Calculation"

55. PVNGS Safety Analysis Design Bases, SABD-8.O1, "Physics PAC, EPAC, andAPAC"56. PVNGS Study 1 3-MS-C045, "Control Room Environmental Evaluation During ELAP"57. PVNGS Calculation 1 3-EC-PK-0204, "Hydrogen Generation Calculation for Class 1 EStation Batteries

-GNB Model Ncn-33"58. PVNGS Document NM1000-A001 15, "Palo Verde Units 1, 2, And 3 Spent Fuel PoolCriticality

-Summary of the Best Estimate Evaluation of the Palo Verde Units 1-3Spent Fuel Pool A Boiling Conditions"

59. Calculation 13-JC-CT-0200, "Setpoints and Total Loop Uncertainty for High/LowCondensate Tank Levels (Loops CTALLOOP0032 and CTBLLOOP0036"

60. PVNGS Document NM1000-A00057, "PVNGS FLEX Mods -Yard Vehicles SeismicStability Analyses:

Separation Requirements for Various Vehicles Under the CanopyStructure to Avoid Seismic Interaction"

61. PVNGS Document NM1000-A001 73, "Palo Verde Nuclear Generating Station FLEXWalk-Down Report"62. PVNGS Document NM1 000-A001 24, Strategic Alliance for FLEX Emergency Response (SAFER) "SAFER Response Plan for Palo Verde Nuclear Generating Station"63. Palo Verde Administrative Procedure 33MT-9CP01, "Venting the Containment inLower Modes"64. Palo Verde Administrative Procedure 01 DP-01S1 7, "Heat Stress Prevention Program"Page 66 of 100 Final Integrated Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 365. Palo Verde FLEX, FLEX Program Manual, "PVNGS Diverse and Flexible CopingStrategies (FLEX) Program Plan"66. Palo Verde Administrative Procedure 40EP-9E008, "Blackout"

67. Palo Verde Administrative Procedure 4OAO-9ZZ21, "Acts of Nature"68. Palo Verde Administrative Procedure 791S-9ZZ07, "PVNGS Extended Loss of AllSite AC Guidelines"

69. Palo Verde Administrative Procedure 791S-9ZZ08, "PVNGS Extended Loss of AllSite AC Guidelines Modes 5&6 and Defueled"

70. Palo Verde Administrative Procedure 40EP-9E01 1, "Lower Mode Functional Recovery"

71. Palo Verde Administrative Procedure 400P-9ZZ23, "Outage GOP"72. Palo Verde Administrative Procedure 14DP-0BD01, "PVNGS Portable FLEXEquipment Deployment"

73. Palo Verde Administrative Procedure 70DP-0RA01, "Shutdown Risk Assessments" External to APS74. NEI 12-01, Revision 0, "Guideline for Assessing Beyond Design Basis AccidentResponse Staffing and Communications Capabilities,"

April 2012. [ADAMSAccession Number ML121 10A204]75. NEI 12-06, Revision 0, "Diverse and Flexible Coping Strategies (FLEX)Implementation Guide," August 2012. [ADAMS Accession Number ML12221A205]

76. Nuclear Management and Resources Council (NUMARC) 87-00, Rev 1, "Guidelines and Technical Bases for NUMARC Initiatives Addressing Station Blackout at LightWater Reactors,"

August 1991.77. EPRI Report NP-6041 -SL, Revision 1, "A Methodology for Assessment of NuclearPlant Seismic Margin,"

August 1991.78. WCAP-17601-P, Revision 1, "Reactor Coolant System Response to the ExtendedLoss of AC Power Event for Westinghouse, Combustion Engineering and Babcock &Wilcox NSSS Designs,"

January 2013.79. NEI 96-07, Revision 1, "Guidelines for 10 CFR 50.59 Evaluations,"

February 2000.[ADAMS Accession Number ML003686043]

80. NERRC101A001

-0235, "National SAFER Response Centers (NSRC) Checklist toDeclare Operational Palo Verde," October 31, 2014.81. NUMARC 91-06, "Guidelines for Industry Actions to Assess ShutdownManagement,"

June 1992.82. INPO 06-008, "Guidelines for the Conduct of Outages at Nuclear Power Plants,"February 2011.83. GOTHIC Thermal Hydraulic Analysis

Package, Version 8.0(QA),

January 2012,Page 67 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2 and 3EPRI, Palo Alto, CA.84.Westinghouse

Document, CN-TDA-1 1-7, Rev. 0, "Software Change Specification and Validation for CENTS Version 11240."85. CENPD-133-P, Revision 0 and Supplements 1, 3-P, "CEFLASH-4A, A FORTRAN-IV Digital Computer Program for Reactor Blowdown Analysis."

86. ORNL RSICC CCC-785, "SCALE 6.1: A Comprehensive Modeling and Simulation Suite for Nuclear Safety Analysis and Design; Includes ORIGEN,"

July 2011.87. ORNL RSICC CCC-750, "SCALE 6: Standardized Computer Analyses for Licensing Evaluation Modular Code System for Workstations and Personal Computers, Including ORIGEN-ARP,"

August 2009.88. ETAP Version 12.6.0.N, Electrical Power Systems Design and Analysis Software.

Irvine, California, USA.89.AFT-Fathom, Version 8.0, Applied Flow Technology.

Colorado

Springs, Colorado, USA.90. US AEC Division of Reactor Development Document TID-7024, "Nuclear Reactorsand Earthquakes,"

August 1963.91. IEEE 485-2010, "IEEE Recommended Practice for Sizing Lead-Acid Batteries forStationary Application,"

April 2011.92. IEEE 450-2002, "IEEE Recommended Practice for Maintenance,

Testing, andReplacement of Vented Lead-Acid Batteries for Stationary Applications,"

April 2003.93. NEI 14-01, Revision 0, "Emergency Response Procedures and Guidelines forBeyond Design Basis Events and Severe Accidents,"

April 2014. [ADAMS Accession Number ML14247A092]

94. The Electric Power Research Institute (EPRI) Report 3002000623, "NuclearMaintenance Applications Center: Preventive Maintenance Basis for FLEXEquipment."

[ADAMS Accession Number ML 13276A573]

95. NEI 97-04, Revision 1, "Design Bases Program Guidelines,"

November 2000.[ADAMS Accession Number ML003679532]

96. INPO AP-91 3, "Equipment Reliability Process Description,"

November 2001.97. NEI Position Paper, "Shutdown

/ Refueling Modes" September 18, 2013 (ADAMSAccession Number ML13273A514)

Page 68 Of 100 Final Integrated PlanNRC Order EA-12-049 Palo Verde Nuclear Generating StationUnits 1, 2 and 3Tables and FiguresTable 1: 480 VAC FLEX Generators Essential Load ListTrain A Train BLoad Load Essential 1 LoadCenters CentersL31 L32 PKC/D-H13/H14 (58kVA) "ClD" Battery ChargerHJA/B-JO1A/B (lhp) "A/B" Battery Compartment L31 L32 Exhaust FanL31 L32 HJA/B-J01 B/A (1 hp) "CID" Battery Compartment Exhaust FanL31 L32 DFA/B-P01 (3hp) Diesel Fuel Oil Transfer PumpL35 L36 PKA/B-H11/12 (80/92kVA)

"A/B" Battery ChargerCHE-P01 (100hp) Swing Charging Pump "E" orL35 L36 30hp electrical portable RCS injection pump.L35 L36 HJA/B-F04 (125hp) Control Room Air Recirculation Note(s):1Generators have additional capacity to power non-essential loads such as stationemergency or normal lighting, HVAC, and communication, if needed. Generators may also be used for non-seismic systems that survive the initiating event.Page 69 of 100 Final Integrated PlanNRC Order EA-12-049 Palo VerdeNuclear Generating StationUnits 1, 2 and 3Table 2:-PVNGS FLEX Phase 2 Equipment Providing Safety Function(s) z "- E " .--Portabe-equiment Specification Operating point Designo 30 p300 00gm@20pi, Diesel driven engine, SS -Centrifugal SG Makeup Pumps 4 X. X X < gpm0 30pgsig00psg pump with dual 5-inch STORZ inlet and(Reference

38) egn@310PM one 5-inch STORZ outlet<60 pm 5 40 gm @650 Electric motor driven engine, positiveHihPesr-C 4 X X X 600 psig psig, engine @ displacement VFC pump with singleInjection Pumps (Reference

37) 100-1 200 RPM STORZ 5-inch suction and single____ ____discharge with 1% inch NPT connection S200 gpm, < 200 gpm @ < 80 Diesel driven engine, SS -Centrifugal SFP Makeup Pumps 4 X X X 100 psig psgpump with dual 5-inch STORZ inlet and(Reference

38) psgone 5-inch STORZ outletRCS owe Moe 20 gp @ 0 pig, Diesel driven engine, SS -Centrifugal RCSLoerp Pmode 4 X X X NA 250gpne @ > psigP pump with dual 5-inch STORZ inlet andone 5-inch STORZ outlet800 kW, 480V Diesel driven, trailer mounted, 750AElectrical Generators 8 X X X 500 kW, 480 V3-hs(Reference 40)3-hs(Reernc 41M20MO 3 per phase, plus ground, neutral, and(Refrenc 41)spare, color coded to NSRC requirement Note(s):1 Same equipment as SG makeup, the SG makeup pump is dual functionPage 70 of 100 Final Integrated PlanNRC Order EA-1 2-049Palo Verde Nuclear Generating StationUnits 1, 2 and 3Table 3: PVNGS Other FLEX Equipment Available on SiteList of key equipment 1 and associated items Total Keyavailable Parameter(s)

Design4 Diesel driven engine, SS -Centrifugal pump with dual 5-inchTransfer Pumps (low flow) 4150 gpm STORZ inlet and one 5-inch STORZ outletPumps (high flow) 2 1500 gpm Electric motor driven submersible pumpPipe ~ ft12 inch, 20 ft. long High Density Polyethylene (HDPE)segmentsElectrical Generators 2 4.16 kV, 2 MW Diesel driven4 x 4/0 cables per phase plus ground, neutral (2/0) cables,2 cable trailer/u nit for 4.16 kV Generators 6 4/0 / 2/0 adsaeElectrical Generators and cables 2 150 kW Diesel drivenNote(s):SNSRC provided equipment list is available in the PVNGS SAFER Response Plan (Reference 62)2Page 71 of 100 Final Integrated PlanNRC Order EA-12-049 Palo Verde Nuclear Generating StationUnits 1, 2 and 3Table 4: PVNGS FLEX Miscellaneous Equipment/Commodities Item NotesPortable Fuel Oil Refueling System Three (3) 500 gallon trailers* Diesel Fuel Oil Delivery Tank Trailers Three (3) diesel driven pumps (60 gpm)=PumpsHeavy Equipment Two (2) commercial trucks for hauling trailers* Transportation Equipment Two (2) yard trucks for generators

Debris Clearing Equipment Three (3) ATIV 4 wheel + tow bars* Communication Vehicles Two (2) mid-size debris removal loaders w/forksFour (4) communication vehiclesMisc 12 Sani-Privy (Portable)

Sani-Privy Page 72 of 100 Final Integrated PlanNRC Order EA-12-049 Palo Verde Nuclear Generating StationUnits 1, 2 and 3Table 5: Sequence of Events Timeline, Modes 1 -4Analytical RequiredItem Elased ctin / Operator FLEX Time Automated te Elpe Acin/ Action Constraint Action Remarks I Applicability

-No. Time Description Time YIN/NA YIN(hours)-(ous Initiating Event NAN Reactor at 100% power, assumed RCS pump seal leakage is 250ENAPN gpm/pump<0.001 Control Rods NAy 10 CFR 50.63 assumption for the designed plant response to a lossInsert NAY of offsite power, turbine trip result in reactor trip2 0.184 AFAS generated NA -Y LWS eeTDAFW flow to3 0.220 both SGs NA y Conservative assumption, time to AFAS generation

+ 60 secondbegins delay for TDAFW pump to start -Estimated time for operator to recognize station black out (SBO).SBO ondiionProcedural requirements are adhered to. Emergency Action Level4 0.25 is0 condiiond N N (EAL) is exceeded and a Site Area Emergency is declared; SBOprocedures instruct the operator to start the station blackoutgenerators (SBOGs).Current design bases for SBO dictates operator action within 1 hr. toSBOGFail tostart the alternate source of power for the station black out scenario.

5BGFis o1NN Therefore, the latest time to enter FSGs (see item 6) will be 1 hr.Startafter initial event. EAL is exceeded and a General Emergency isdeclared.

Enter FSG ~1YFLEX coping starts: RCS cool-down

@ 70 degrees F / hr., symmetric 6Guidelines 1 N cool-down using 1 ADV per train and DC load shed sequence starts.7 Complete DC2YN DClashdsqeccoptd 2Load Shed Y Cla hdsqec opeePage 73 of 100 Final Integrated PlanNRC Order EA-1 2-049Palo Verde Nuclear Generating StationUnits 1, 2 and 3AnalyicalRequired AnalyicalOperator FLEX Time Automated Itm Easd Ato Action Constraint Action Remarks I Applicability No. Time " Description Time Y/NINA YIN (hours)Open the'TDAFW pump 'Action limits environmental temperature rise within the essential 8 2Compartment 2 Y N TDAFW pump compartment and reduces possibility of AF system(train A) Door component failure.and/for HatchRCS borated makeup starts. RCS depressurizes to a lower pressure9SsbeitoN Y than the SIT nitrogen blanket.

Operators will trend RCS pressure andinjectvent SIT N2 when SIT level reaches 10%.Cool-down

,Cool-down

/ depressurization of the RCS will result in reduced lossachieved, RCS of RCS inventory due to RCP Seal leakage.

The RCS cool-down willabove stop at P/T near shutdown cooling entry condition.

FSGs provide'10 ~ shutdown N N guidance to maintain secondary pressure (steam generator dome.-cooling entry pressure) such that essential TDAFW steam supply will remainP/T condition above the TDAFW required pressure for efficient operation.

Completion of Primary and Secondary side equipment status walk-~downs. Specific tasks within the walk-downs have time constraints.

11 ~~Assessment 4YN Drn h orhuso akdwsadtoa nnw cin a114 Drngth ou ousWalk-downsdiina nkow ctos aWalk-ownsbe required depending on the severity of the BDBEE. Entry intoSAMGs may be evaluated based on level of damage.Roll up door to the Fuel Building truck bay is opened prior to earliestEsabihigpredicted spent fuel pool time to boil. This action would provide.Establshingventilation and maintain accessibility to alternate SEP makeup pump12 Fel Bildng 4N N connection point. This is not a required action since access is notVentPathrequired to the building and there is no permanent equipment withinthe building that is used for coping strategies.

Page 74 of 100 Final Integrated PlanNRC Order EA-12-049 Palo Verde Nuclear Generating StationUnits 1, 2 and 3Analytical RequiredItem Elased ctin I Operator FLEX Time Automated te Elpe Acin Action Constraint Action Remarks I Applicability No. Time Description TieINA YN(hours) (hours)Minimum time to exhaust seismic nitrogen supply to ADVs (perBegi Manallydesign).

Manual operation of ADVs will be initiated if needed.13 16Oeraing 16nuYlNyMinimal adjustment will be needed since manipulation is only neededAD~s to maintain SG pressure.

Auxiliary Operators are trained for this task.AD~s Area is habitable since upper MSSS is open to the environment.

Additionally, power sources to ADVs would be load shed at this time.480 VACAC power source is in place and available for loads identified in14 Geeratrs 3 Y N Table I of this report.Implemented Star ChagingLoads in Table 1 of report are aligned to 2 x 800 kW generators per15 35.51 Pump or FLEX 34.5 Y N FSG direction.

RCS borated makeup is established as a top priorityRCS injection

, load.pump16Stage SG SG makeup pump is staged and operational.

This is a contingency 16Makeup Pump 35 N .N action to limit essential TDAFW pump trip impact should the suctionbe lost as a result of action item 18.Approximate time SFP inventory is 10 feet above the irradiated fuelEstablish SEP N in the spent fuel pool storage rack. Batch makeup to SFP isMakeupestablished to maintain water level between normal (138 ft.) and 10ft. above rack per NRC Order EA-12-051 (Reference 2).Switchover to TDAFW pump suction is realigned to the RMWT by manipulation of1 40RMWT N manual valves. See Figure 5.Page 75 of 100 Final Integrated PlanNRC Order EA-12-049 Palo Verde Nuclear Generating StationUnits 1, 2 and 3Analytical RequiredItem Elased ctin I Operator FLEX Time Automated Itm Eas d eAcition"

/ Action Constraint Action Remarks I Applicability No Tm Dscitin Time YIN/NA YIN(hours) (hours)Water fromlong term At 104 hours0.0012 days 0.0289 hours 1.719577e-4 weeks 3.9572e-5 months the water within the power block in the CST and RMWT19 104 sources of 72 N N is depleted; long term source of water will be available (see Section,water is 10 of report).available.

Note(s):1 Analytically determined using CENTS code (Internal Document and Calculation Reference 34); a one hour time averaged flow through the top of the SG U-tubes exceeds a value of 0.1. This provides a reasonable transition point to the onset of reflux cooling and provides the guidance for initiating RCS forcedinjection to maintain natural circulation (Reference 16).Page 76 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2 and 3Figure 1: FLEX Primary and Alternate RCS Injection Schematic for Modes 1 -4cm=._9.. --co,,, q-iIJW7 EVll$ SU5 SUWI27 LOOp2IACaieol~gCHV-4

" PipeCi ___s _ STORZ S VI lv1(nt i+. ----s " r, Pi.,p DC0: NIJ2JDNP3

-+t. (N.e I*(NA* Mcommort~i onyalew Nghihgg re~at FLEX memffc.nlons to PVNGSNotel : Wies. 1.0010 rotated aol addlenal coipnpats (suof asw twa y ettfed) owy Ho usedPage 77 of 100 Final Integrated PlanNRC Order EA-12-049 Palo Verde Nuclear Generating StationUnits 1, 2 and 3Figure 2: FLEX Primary RCS Injection Tie-in Simplified PipingLJPage 78 of 100Page 78 of 100 Final Integrated PlanNRC Order EA-12-049 Palo Verde Nuclear Generating StationUnits 1, 2 and 3Figure 3: FLEX Alternate RCS Injection Tie-in Simplified PipingDischarge connection into pipe onelevation that ties into HPSI linedownstream of isolation valvePage 79 of 100 Final Integrated PlanNRC Order EA-12-049 Palo Verde Nuclear Generating StationUnits 1, 2 and 3Figure 4: FLEX RCS Makeup Schematic for Modes 5 and 6sIB~tFrom HSI8HV6SIS 6 PipeC._J. HEV1009e5k QAG PIA--- ISTORZSIAUV63S L N"I m'IA(nHose t1 NSLocation:

Somfihyord over Essential Tunnel omeca:SIAUV845 I. Diosol Pump DaID: A11J213MBDN4P02

....... -m "....-3*

9* "4 .---sjpSTO4Z S 7IPdSIDUVOIS~PdCold LegSIAUV6I7 SIEVII3 slEvMo ~ Loop 2ACold LegLoop 2BCold LegLoop 1ACold LegLoop l BYellow highlight reflects FLEX modifications to PVNGSNote I: Hose asfield routed and aditonl components (much as two way manifolds) may be usedPag 80of10Page 80 of 100 Final Integrated PlanNRC Order EA-12-049 Palo Verde Nuclear Generating StationUnits 1, 2 and 3Figure 5: FLEX Primary and Alternate Secondary Makeup Schematic Class Q rCTIEV057AF Break QAG STOR 1F 4V2AFCUV3G

D Au Fed ...5"8TOZ4.Hos AFCHV33 AFAUV37 ICommercial I(Note 1)Ie *oe3 PpSuction for either pump : -S AFBV530 AFBV52U09Location:

Plant NW of CST Cmeca:iro Aux Fee B Diesel Pump OCID: A/ll2/3MBDNPO24".. Hose.-Suction foreither pumpClassem Green is the alternate makeup pathYellow highlight reflects FLEX modifications to PVNGSNote 1: Hose is field routed and additional components (such as two way manifolds) may be usedPage 81 of 100Page 81 of 100 Final Integrated PlanNRC Order EA-12-049 Palo Verde Nuclear Generating StationUnits 1, 2 and 3Figure 6: FLEX Secondary Plant Makeup Simplified Piping-Primary Connection

-Secondary Connection

-Common Suction Pipefrom Train "B"MS HosesII III I IIIIII I IIIII II I II II III IContainment Page 82 of 100 Final Integrated PlanNRC Order EA-12-049 Palo Verde Nuclear Generating StationUnits 1, 2 and 3Figure 7: FLEX 480 VAC Physical LayoutIPNot t3of 100lPage 83 of 100 Final Integrated PlanNRC Order EA-12-049 Palo Verde Nuclear Generating StationUnits 1, 2 and 3Figure 8: FLEX 480 VAC Electrical Schematic Page 84 of 100 Final Integrated PlanNRC Order EA-12-049 Palo Verde Nuclear Generating StationUnits 1, 2 and 3Figure 9: FLEX Motor Driven RCS Injection Physical Cable Layout (Ground Elevation)

INReactorMakeupTankPa a.? ,=

elevation 120 ft. / MCC E-PHB-M-MCCC E-PHB-M36and new disconnect

-- * ,~witches Docaion otor t ReactorHold -upTankSPrimary locationMotor driven RcS .injection pump,, ,.5F} ft. Cableextension i:(~~;z:~ /r~IIL ....---- l m' Z.LNJ ~\~y{ a. a i~4r~a~ TflV no. flt etc pperr(Poge 85 of100Page 85 of 100 Final Integrated PlanNRC Order EA-12-049 Palo Verde Nuclear Generating StationUnits 1, 2 and 3Figure 10: FLEX Electrical Modifications Schematic

>/ESF X03transformer OfltESF X04Stransformerpweter-M36LegendNew FLEX prnmalyCable / Bus &Equipwent INew FLEX alternaeCable/Bus

&Equipnment 1LExiting ecupmleent New Cable / Bus & Equipmeent

... .4,Page 86 of 100 Final Integrated PlanNRC Order EA-12-049 Palo Verde Nuclear Generating StationUnits 1, 2 and 3Figure 11: Defense-in-Depth 4.16 kV AC Physical LayoutorI IDiesel Generator IRouted to: 4 MWe, 4.16 kVexternal power source1*(Not to scale)Page 87 of 100 Final Integrated PlanNRC Order EA-12-049 Palo Verde Nuclear Generating StationUnits 1, 2 and 3Figure 12: Defense-in-Depth 4.16 kV AC Electrical Schematic ONSITEPOW#ERSOURCEPage 88 of 100 Final Integrated PlanNRC Order EA-12-049 Palo Verde Nuclear Generating StationUnits 1, 2 and 3Figure 13: FLEX Primary and Alternate SFP Makeup Schematic for All Modes (FLEX SFP Pump Discharge)

Primary Fukushima Makeup Headerinto the SFP4" Hose 5" STORZ4" PipePCNV243COlTLocation:

Plant North of Fuel BuildingDiesel Pump DCID: A/II2I3MBDNP04 nmercia4" HoseQJ a .-.I-4" PipeI --PCNV242STORZIAlternate Fukushima Makeup Headerinto the SFPBlue is the primary makeup path-,,--Green is the alternate makeup pathYellow highlight reflects FLEX modifications to PVNGSNote 1: Hose is field routed and additional components (such as two way manifolds) may be usedPage 89 of 100 Final Integrated PlanNRC Order EA-12-049 Palo Verde Nuclear Generating StationUnits 1, 2 and 3Figure 14: FLEX Primary and Alternate SFP Makeup Schematic (FLEX SFP Pump Suction)RWTCHEV0116" Pipe......,1 5" STORZ"4" HoseCommercial U (Note 1)'ISuction for either pumpI.Class__g_

Break QAGCHEVIO093" PipeAFNV5355" STORZ;' 4" HoseCommercial I (Note 1)ISuction for either pump5,,Commercial 4" Hose(note 1)ISSuction for either pmSFP Makeup Pump Water Source during Refueling SFP Makeup Pump Water Source during Power Operation Blue is the primary makeup path-Green is the alternate makeup pathYellow highlight reflects FLEX modifications to PVNGSNote 1: Hose Is field routed and additlonai components (such as two way manifolds) may be usedPage 90 of 100 Final Integrated PlanNRC Order EA-12-049 Palo Verde Nuclear Generating StationUnits 1, 2 and 3Figure 15: FLEX Primary and Alternate SFP Makeup Simplified PipingPreferred Suctionsources duringRefueling MAIN1 HATLH-'-----CONTAINMF.NT I BLDG.~-AUX. BLDG.PrimaryONot all lcomponents are shown;Jsee Figurel 14for details.O1NV019lFN535Alternate Preferred Suctionsource during PowerOperation Legendi,,..Blue is the FLEX primary makeup pathSGreen is the FLEX alternate makeup pathYellow highlight reflects SFP Seismic CAT I boundary with PVNGSPage 91 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1,2 and 3Figure 16: Photograph of Primary and Alternate SFP Makeup Piping and Nozzles within the Fuel BuildingPage 92 of 100 Final Integrated PlanNRC Order EA-12-049 Palo Verde Nuclear Generating StationUnits 1, 2 and 3Figure 17: FLEX Containment Vent Path Configuration in Lower ModesPage 93 of 100Page 93 of 100 Final Integrated PlanNRC Order EA-12-049 Palo Verde Nuclear Generating StationUnits 1, 2 and 3Figure 18: FLEX EESF and VicinityPage 94 of 100 Final Integrated PlanNRC Order EA-12-049 Palo Verde Nuclear Generating StationUnits 1, 2 and 3Figure 19: FLEX Deployment Locations (Seismic Pads and Tie-downs forPumps and Generators)

Not to ScaleUnit 2 is shown; Units 1 & 3 are similarPage 95 of 100 Final Integrated PlanNRC Order EA-12-049 Palo Verde Nuclear Generating StationUnits 1, 2and 3Figure 20: FLEX Deployment RoutesPage 96 of 100 Final Integrated PlanNRC Order EA-12-049 Palo Verde Nuclear Generating StationUnits 1, 2 and 3Figure21: FLEX Primary and Alternate SG Makeup Pump Deployment Arrangement Page 97 of 100 Final Integrated PlanNRC Order EA-12-049 Palo Verde Nuclear Generating StationUnits 1, 2 and 3Figure 22: FLEX Primary and Alternate SFP Makeup Pump and Primary RCS Injection Pump Deployment Arrangements Page 98 of 100 Final Integrated PlanNRC Order EA-12-049 Palo Verde Nuclear Generating StationUnits 1, 2 and 3Figure 23: FLEX Alternate RCS Injection PumpDeployment Arrangement at Ground Level in the Auxiliary BuildingLookin sout fromthe FEX RCSpump9kidoLcatio Page 99 of 100 Final Integrated PlanNRC Order EA-12-049 Palo Verde Nuclear Generating StationUnits 1, 2 and 3Figure 24: FLEX Deployment Arrangement for 480 V, 800 kW Generators and Defense-In-Depth 4.16 kV, 4MW (Total) Generators Note t00of ScalPage 100 of 100 EA-12-049 QapsMaria L. LacalVice President, NuclearRegulatory

& Oversight Palo VerdeNuclear Generating StationP.O. Box 52034Phoenix, AZ 85072Mail Station 7605Tel 623.393.6491 102-07159

-M LL/TN WDecember 24, 2015U.S. Nuclear Regulatory Commission ATI'N: Document Control Desk11555 Rockville PikeRockville, MD 20852

References:

1. NRC Order Number EA-12-049, Order Modifying Licenses withRegard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events, dated March 12, 20122. NRC Interim Staff Guidance JLD-ISG-2012-01, Compliance withOrder EA-12-049, Order Modifying Licenses with Regard toRequirements for Mitigation Strategies for Beyond-Design-Basis External Events, Revision 0, dated August 29, 20123. NEI 12-06, Diverse and Flexible Coping Strategies (FLEX)Implementation Guide, Revision 0, dated August 21, 20124. APS Letter 102-06670, APS Overall Integrated Plan in Response toMarch 12, 2012 Commission Order Modifying Licenses with Regardto Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049),

dated February 28,2013

Dear Sirs:

Subject:

Palo Verde Nuclear Generating Station (PVNGS)Units 1, 2, and 3Docket Nos. STN 50-528, 50-529, and 50-530APS Final Integrated Plan in Response to March 12, 2012Commission Order Modifying Licenses with Regard toRequirements for Mitigation Strategies for Beyond-Design-Basis External Events (order Number EA-12-049)

On March 12, 2012, the Nuclear Regulatory Commission (NRC) issued an order(Reference

1) to Arizona Public Service Company (APS). Reference 1 wasimmediately effective and directs APS to develop, implement, and maintain guidanceand strategies to maintain or restore core cooling, containment, and spent fuel poolcooling capabilities in.the event of a beyond-design-basis external event. Specificrequirements are outlined in Attachment 2 of Reference 1.Reference 1 required submission of an overall integrated plan (OIP) by February 28,2013. The NRC Interim Staff Guidance (ISG) (Reference

2) was issued August 29,2012 which endorses industry guidance document NEI 12-06, Revision 0 (Reference

3) with clarifications and exceptions.

APS provided the OIP (Reference

4) pursuant toSection IV, Condition C.1, of Reference 1.A member of the STARS (Strategic Teaming and Resource Sharing)

AllianceCallaway

Diablo Canyon

Palo Verde

Wolf Creek 102-07159-MLL/TNW ATTFN: Document Control DeskU.S. Nuclear Regulatory Commission APS Final Integrated Plan in Response to March 12, 2012 Commission OrderModifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049)

Page 2The NRC staff subsequently requested that, within 60 days of the date for the finalunit to achieve compliance at their plant, licensees submit a Final Integrated Plan(FIP), reflecting the strategies for their plants on that date. This letter transmits theFIP for PVNGS Units 1, 2, and 3. The information in the FIP supersedes theinformation provided in the OIP.The NRC also requested that, within 60 days of the compliance date for the final unitat their plant, licensees submit responses tO the NRC Open Items, Confirmatory Items, and Audit Items identified by the staff regarding the mitigation strategies implemented at their sites. The APS response for the Palo Verde Nuclear Generating Station (PVNGS) site was submitted by letter number 102-07157, dated December17, 2015.No commitments are being made to the NRC by this letter.Should you have any questions concerning the content of this letter, please contactThomas Weber, Department Leader, Regulatory

Affairs, at (623) 393-5764.

I declare under penalty of perjury that the foregoing is true and correct.Executed on December 24, 2015* (Date)Sincerely, MLL/TNW/PJH/af

Enclosure:

Final Integrated Plan Palo Verde Nuclear Generating Station (PVNGS)Units 1, 2, and 3cc: M. L. Dapas NRC Region IV Regional Administrator M. M. Watford NRC NRR Project ManagerL. J. KIos NRC NRR Project ManagerC. A. Peabody NRC Senior Resident Inspector J. P. Boska NRC NRR/JLD/JOMB Project Manager ENCLOSURE FINAL INTEGRATED PLANPALO VERDE NUCLEAR GENERATING STATIONUNITS 1, 2 AND 3 Final Integrated PlanNRC Order EA-12-049, Palo Verde Nuclear Generating StationUnits 1, 2 and 3FINALINTEGRATED PLANPALO VERDE NUCLEAR GENERATING STATIONUNITS 1, 2AND 3Page 1 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2 and 3Table of ContentsTable of Contents

.......................

.....................................................

2List of Tables ...........................

.......

...............................................

4List of Figures .....................................

4Acronyms

.......................................................................................

6Executive Summary.........................................................................

101. Background

....................

......................

................................

122. General Integrated Plan Elements

................................................

132.1. Assumptions......................14 2.2. Analytical Methods and Computer Codes used in Key Analyses

........

152.3. Procedural controls...............

....... 203. Strategies.....................................................

.... ....................

204. Reactor Core Cooling and Heat Removal Strategy.............................

214.1. Reactor Coolant System at power ..........................................

214.2. Reactor Coolant System at Lower Modes..................................

254.3. Systems, Structures, Components

.. ......................................

274.4. FLEX Modifications in Support of Phases 2 and 3 ........................

314.5. Key Reactor Parameters..................38

5. Spent Fuel Pool (SFP) Cooling/Inventory Strategy..............................

395.1. Spent Fuel Pool Cooling Strategy, ELAP During Power Operation

.....405.2. Loss of Power with a Full Core Off-Load (at least 100 hours0.00116 days 0.0278 hours 1.653439e-4 weeks 3.805e-5 months intorefueling)

......................................................................

415.3. Systems, Structures, Components

...................................

.......425.4. SFP Cooling Modifications

...................................................

425.5. Key Spent Fuel Pool Parameters...........................................

436. Containment Integrity Strategy

.....................................................

436.1. Containment Integrity at Power.............................................

436.2. Containment Integrity during Modes 5 and 6 (fuel in reactor vessel and inthe containment with no fuel movement)...................................

436.3. Systems, Structures, Components

.........................................

446.4. Key Containment Parameters

..............................................

446.5. FLEX Modifications

.....................................

............

.........

457. Characterization of External Hazards ..........................................

...457.1. Seismic ............

....................

457.2. High Temperatures

.... ................

...467.3. Not Applicable External events ...............................................

468. Protection of FLEX Equipment

.....................................

... .............

478.1. FLEX Emergency Equipment Storage Facility and Deployment..........

478.2. FLEX Deployment Pads..............................

48Page 2 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2 and 39. Planned Deployment of FLEX Equipment.,

...............

........................

489.1. Deployment Routes...............

.............

...............................

489.2. Accessibility

...................................

... .............................

489.3. On-Site Fuel Storage Tanks and Qualifications............................

4910. Deployment of Major FLEX Equipment and Strategies

........................

4910.1. Reactor Core Cooling and Heat Removal Equipment Deployment andAssociated Water Inventory Sources .......................................

4910.2. RCS Injection Skid Deployment and Associated Water Inventory Sources5010.3. SFP Makeup Pump Deployment and Associated Water Inventory Sources .........................................

....:..........................

5110.4. FLEX 480 VAC Electrical Generator Deployment.........................

5110.5. Defense-in-Depth 4.16 kV 4 MW Electrical Generator Deployment.....52 10.6. Fueling of Equipment........................................................

5211. Offsite 5311.1. National SAFER Response Center.........................................

5312. Equipment List...........,............................................................

5313. Habitability and Operations

..........................................

,...............54 13.1. Equipment Operating Conditions...,.........................................

5413.2. Personnel Habitability.........................................................

5413.3. Lighting

...............

.........

..............................................

5513.4. Communications

..........

..................................................

5513.5. Additional Water Sources....................................................

5613.6. Staffing

.. .....................................................................

5614. Sequence of Events .......

5615. Programmatic Elements

.... .... ..................................................

5715.1. Overall Program Document

..........

.......................................

5715.2. Procedural Guidance

........................................................

5815.3. Organizational responsibilities

..............................................

5915.4. Training

........,...............

...............................................

6015.5. Equipment Maintenance and Testing .... ..............................

i......61 References

.................................................................

.....................

62Regulatory.............

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62APS Documents...............................

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65External to APS........................................................................

67Tables and Figures......;...........................:............................................69 Page 3 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2 and 3List of TablesTable 1: 480 VAC FLEX Generators Essential Load List..............................

69Table 2: PVNGS FLEX Phase 2 Equipment Providing Safety Function(s)..........

70Table 3: PVNGS Other FLEX Equipment Available on Site ...........................

71Table 4: PVNGS FLEX Miscellaneous EquipmentlCommodities

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72Table 5: Sequence of Events Timeline, Modes I -4....................................

73List of FiguresFigure 1 : FLEX Primary and Alternate RCS Injection Schematic for Modes I -4.. 77Figure 2: FLEX Primary RCS Injection Tie-in Simplified Piping......................

78Figure 3: FLEX Alternate RCS Injection Tie-in Simplified Piping ....................

79Figure 4: FLEX RCS Makeup Schematic for Modes 5 and 6 ..........................

80Figure 5: FLEX Primary and Alternate Secondary Makeup Schematic

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81Figure 6: FLEX Secondary Plant Makeup Simplified Piping ..........................

82Figure 7: FLEX 480 VAC Physical Layout ...............................................

83Figure 8: FLEX 480 VAC Electrical Schematic

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84Figure 9: FLEX Motor Driven RCS Injection Physical Cable Layout (GroundElevation)

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85Figure 10: FLEX Electrical Modifications Schematic

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86Figure 11: Defense-in-Depth 4.16 kV AC Physical Layout ............................

87Figure 12: Defense-in-Depth 4.16 kV AC ElectricaliSchematic.......................

88Figure 13: FLEX Primary and Alternate SFP Makeup Schematic for All Modes(FLEX SFP Pump Discharge)

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89Figure 14: FLEX Primary and Alternate SFP Makeup Schematic (FLEX SFP PumpSuction)....

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90Figure 15: FLEX Primary and Alternate SFP Makeup Simplified Piping.............

91Page 4 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 3Figure 16: Photograph of Primary and Alternate SFP Makeup Piping and Nozzleswithin the Fuel Building.......................................................

92Figure 17: FLEX Containment Vent Path Configuration in Lower Modes ..........

93Figure 18: FLEX EESF and Vicinity

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94Figure 19: FLEX Deployment Locations (Seismic Pads and Tie-downs for Pumpsand Generators)..............

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95Figure 20: FLEX Deployment Routes ..........................................

i...........96 Figure 21: FLEX Primary and Alternate SG Makeup Pump Deployment Arrangement

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97Figure 22: FLEX Primary and Alternate SFP Makeup Pump and Primary RCSInjection Pump Deployment Arrangements

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98Figure 23: FLEX Alternate RCS Injection Pump Deployment Arrangement atGround Level in the Auxiliary Building......................................

99.Figure 24: FLEX Deployment Arrangement for 480 V, 800 kW Generators andDefense-In-Depth 4.16 kV, 4 MW (Total) Generators....................

100Page 5 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 3AcronymsAC.............................................................

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Alternating CurrentADAMS ........................

Agencywide Documents Access and Management SystemADV...................................................................

Atmospheric Dump ValveAFAS ...................................................

Auxiliary Feedwater Actuation SignalAFT .............

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Applied Flow Technology AFW ........................................................................

Auxiliary Feedwater AHU ...........................................................................

Air Handling UnitAPS .........................................................

Arizona Public Service CompanyAOP..........................................................

Abnormal Operating Procedures ASCE ............

American Society of Civil Engineers ASHRAE....American Society of Heating, Refrigerating and Air-Conditioning Engineers ASME............................................

American Society of Mechanical Engineers ASTM... ........................................

..American Society for Testing and Materials BDB....................................................

Beyond-Design-Basis BDBEE .. .............................................

Beyond-Design-Basis External EventsBtu ...........................................................................

British thermal unitCE.....................................................................

Combustion Engineering CET..................................................................

Core Exit Thermocouples CENTS...............................

Combustion Engineering Nuclear Transient Simulator CRE.....................................................................

Control Room EnvelopeCST .................................................................

Condensate Storage TankCVCS .................................................

Chemical and Volume Control SystemDG .............................................................................

DieselIGenerator DC.............................................

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Direct CurrentEAL ..............

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Emergency Action LevelEC .........................................................................

Engineering ChangeECCS .........................

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Emergency Core Cooling SystemEDMG ...............................................

Extreme Damage Mitigation Guidelines EESF............................

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Emergency Equipment Storage FacilityELAP ......................

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Extended Loss of Alternating Current PowerEOF....................................

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Emergency Operations FacilityPage 6 of 100' Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-1 2-049 Units 1, 2 and 3EOP..........................

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.Emergency Operating Procedure EPRi ...................................

Electric Power Research Institute ERO......................................................

Emergency Response Organization ESF ..............................

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Engineered Safety FeatureETAP ..................................................

Electrical Transient Analyzer ProgramF ..........................

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Fahrenheit FSG ... .................................

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FLEX Support Guidelines FLEX....................-...............................

Diverse and Flexible Coping Strategies FMEA .........................................................

Failure Modes Effects Analysisg p m .. ........................................................................

G a llo n s p e r M in uteGOTHIC ..................

Generation of Thermal-Hydraulic Information for Containments HCLPF........................................

High Confidence of Low Probability of FailureHDPE ..........

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....High Density Polyethylene HELB ..............

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High Energy Line BreakHPSI......................High Pressure Safety Injection HVAC ........

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Heating, Ventilation, and Air Conditioning IEEE.........................................

Institute of Electrical and Electronics Engineers INPO ............................................ Institute of Nuclear Power Operations ISG ........................................................................

Interim Staff GuidanceKeff ....................

K effective, neutron multiplication, used as a measure of criticality safetyKSB..........

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Klein, Schanzlin

& BeckerLCO..................

...Limiting Condition for Operation LOCA......................

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Loss of Coolant AccidentLOP ................

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...Loss of PowerLPSI........................................

...... Low Pressure Safety Injection LUHS........................................................,

... Loss of the Ultimate Heat SinkMAAP.................Modular Accident Analysis ProgramMCC ...............

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Motor Control CenterMS ........................

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Microsoft MSSS ..........................................................

Main Steam Support Structure MSSV...;.............................................................

Main Steam Safety ValveNC ..................

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Natural Circulation Page 7 of 100 Final Integrated Plan Palo Verde Nuclear Generating StationNRC Order EA-12-049 Units 1, 2and 3NEI......................................................................

Nuclear Energy Institute NEMA .........

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National Electrical Manufacturers Association NRC .................

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US Nuclear Regulatory Commission NSRC ......................................................

National SAFER Response CenterNSSS .......................................

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,......Nuclear Steam Supply SystemNTTF ...................................

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..Near-Term Task ForceOBE...............................................................

Operating Basis Earthquake alP .... ..................

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Overall Integrated PlanORIGEN........................................................

Oak Ridge Isotope GENerator PEICo...................:..............................

Pooled Equipment Inventory CompanyPM.......

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Preventative Maintenance PMF ...................

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Probable Maximum FloodPMP. ..... .........

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Probable Maximum Precipitation ppm............................

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Parts per Millionpsia ...................

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Pounds per Square Inch Absolutepsig....

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Pounds per Square Inch GaugePVNGS ....................................

....... ...Palo Verde Nuclear Generating StationPWROG .....................................

.:...Pressurized Water Reactor Owners GroupQ1 E .................................................

Quality "Q" Class 1 Electrical Equipment RAI .....................

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Request for Additional Information RCP......................................................................

Reactor Coolant PumpROS ....................

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Reactor Cooling SystemRHR....................................................................

Residual Heat RemovalRMWT-...................................................

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Reactor Makeup Water TankRPM..........

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Revolutions per MinuteRVLMS..........................................

... Reactor Vessel Level Monitoring SystemRWT ...................................................

.i.......Refueling Water TankSAFER ..................................

Strategic Alliance for FLEX Emergency ResponseSAMG .............................................

Accident Mitigation Guidelines SAT.........................................................

.Systematic Approach to TrainingSBCS ..............

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Steam Dump and Bypass Control SystemSBO ................................................

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Station BlackoutPage 8 of 100 Final Integrated PlanNRC Order EA-1 2-049Palo Verde Nuclear Generating Station.Units 1, 2 and 3SBOG ..............................................................

Station Blackout Generator SER...................................................................

Safety Evaluation ReportSEP ......................................

Fuel PoolSG....................

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Steam Generator SIT.......................

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Safety Injection TankSS .....................................................

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.. ......Stainless SteelSSC .....................................................

Structures,

Systems, and Components SSE ..................................................................

Safe Shutdown Earthquake TDAFW .........................................

.......'...Turbine Driven Auxiliary Feedwater UFSAR ......................

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iUpdated Final Safety Analysis ReportUGS .....i..........................*.................................

..... Upper Guide Structure UHS...................................................................

.......Ultimate Heat SinkUSGS........................................................

United States Geological SurveyVAC .................................................................

Volts -Alternating CurrentVDC .............

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Volts -Direct CurrentVFC .....................

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Variable Frequency ControlWR ..................................................................................

Wide RangePage 9of 100' Final Integrated Plan Palo Verde Nuclear Generating Station*NRC Order EA-1 2-049 Units 1, 2 and 3Executive SummaryOn March 12, 2012, the Nuclear Regulatory Commission (NRC) issued Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events, to all licensees requiring implementation ofmitigation strategies for beyond-design-basis external events (BDBEE),

as identified inNear-Term Task Force (NTTF) Recommendation 4.2. Order EA-12-049 requiredsubmission of a Final Integrated Plan (FIP) to the NRC after full compliance with thereferenced orders. In order to assist the industry in responding to the NRC order, theNuclear Energy Institute (NEI) developed guidance in report number 12-06, "Diverseand Flexible Coping Strategies (FLEX) Implementation Guide." NRC interim staffguidance (ISG) JLD-ISG-2012-01

endorses, with clarifications, the methodologies described in NEI 12-06.This submittal describes the Palo Verde Nuclear Generating Station (PVNGS) FIP,including key assumptions, implementing strategies, and operator action times forcomplying with the NRC order and implementing FLEX, as described by JLD-ISG-2012-01 and NEI 12-06. The PVNGS FIP contains a description of the general elements ofthe plan, followed by a discussion of the safety functions that are identified in the order,which are core cooling, containment integrity, and spent fuel pool cooling.The NRC order requires that the underlying strategies for coping with BDBEE involve athree-phase approach:*

Phase 1 -Initially cope relying on installed equipment and on-site resources.

Phase 2 -Transition from installed plant equipment to on-site FLEXequipment.

Phase 3 -Obtain additional capability and redundancy from off-site equipment and resources until power, water, and coolant injection systems are restoredor commissioned.