ML16043A361

Palo Verde, Units 1, 2, and 3 - Supplemental Information Regarding License Amendment Request to Revise Technical Specifications to Incorporate Updated Criticality Safety Analysis

ML16043A361
Person / Time
Site:	Palo Verde
Issue date:	01/29/2016
From:	Lacal M L Arizona Public Service Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
102-07181-MLL/TNW
Download: ML16043A361 (16)

Text

10 CFR 50.90Maria L. LacalVice President, NuclearRegulatory

& Oversight OapsPalo VerdeNuclear Generating StationP.O. Box 52034Phoenix, AZ 85072Mail Station 7605Tel 623.393.6491 102-07181-MLL/TNW January 29, 2016U. S. Nuclear Regulatory Commission ATTN: Document Control DeskWashington, DC 20555-0001

References:

1. Arizona Public Service Company (APS) letter number 102-07149, License Amendment Request to Revise Technical Specifications toIncorporate Updated Criticality Safety Analysis, dated November 25,2015, [Agencywide Documents Access and Management System(ADAMS) Accession Number M L15336A25 1]2. NRC letter Palo Verde Nuclear Generating

Station, Units 1, 2, and 3 -Supplemental In formation Needed for Acceptance of Requested Licensing Action Re: License Amendment Request to Revise Technical Specifications to Incorporate Updated Criticality Safety Analysis, datedJanuary 15, 2016 (ADAMS Accession No. ML16014A001)

Palo Verde Nuclear Generating Station (PVNGS)Units 1, 2, and 3Docket Nos. STN 50-528, 50-529, and 50-530Supplemental Information Regarding License Amendment Request toRevise Technical Specifications to Incorporate Updated Criticality Safety Analysis

Subject:

In reference 1, Arizona Public Service Company (APS) submitted a license amendment request (LAR) to revise the PVNGS Technical Specifications (TS) for Palo Verde NuclearGenerating Station (PVNGS) Units 1, 2, and 3. The proposed amendment would modify TSrequirements to incorporate the results of an updated criticality safety analysis for both newand spent fuel storage.

In reference 2, the Nuclear Regulatory Commission (NRC) staffrequested supplemental information to support the acceptance review of the LAR.The enclosure to this letter provides supplemental information in response to the NRCrequest.

The enclosure also contains three attachments.

Attachment 1 provides the revisedAPS response to significant hazards consideration questions 1 and 2. The original APSresponse to question 3 of the significant hazards consideration remains unchanged.

Attachment 2 provides a marked-up TS page that includes the requested information regarding interface requirements mentioned in NRC supplemental information requestnumber 2. Attachment 3 provides the revised (clean) TS page.This submittal does not contain any new regulatory commitments as defined by NEI 99-04,Guidelines for Managing NRC Commitment

Changes, Revision 0.A memb~er of the STAR (Strategic Teaming and Resource Sharing)

Alliance Clwy DiboCno PaoVerd WolfCre 102-07181

-MLL/TNWATTN: Document Control DeskU. S. Nuclear Regulatory Commission Supplemental Information Regarding License Amendment Request to Revise Technical Specifications to Incorporate Updated Criticality Safety AnalysisPage 2In accordance with the PVNGS Quality Assurance

Program, the Plant Review Board and theOffsite Safety Review Committee have reviewed and approved the proposed changes to theLAR. By copy of this letter, this change to the LAR is being forwarded to the ArizonaRadiation Regulatory Agency in accordance with 10 CFR 50.9 1(b)(1).Should you have any questions concerning the content of this letter, please contact ThomasWeber, Department Leader, Nuclear Regulatory

Affairs, at (623) 393-5764.

I declare under penalty of perjury that the foregoing is true and correct.Executed on: January 29, 2016(Date)Sincerely, IiDigitally signed by Andrews, GeorgeAnd rews, George Dgcgn=Andrews, GeorgeW(978

%AlIT(t'3-1 am approving this documentW L /' =I'R' delegated for Maria Lacal./J Date: 2016.01.29 14:44:37

-07'00'MLL/TNW/CJS/af

Enclosure:

Supplemental Information Regarding License Amendment Request to ReviseTechnical Specifications to Incorporate Updated Criticality Safety Analysiscc: M. L. Dapas NRC Region IV Regional Administrator

• M. M. Watford NRC NRR Project Manager for PVNGSL. J. KIos NRC NRR Project ManagerC. A. Peabody NRC Senior Resident Inspector for PVNGSA. V. Godwin Arizona Radiation Regulatory Agency (ARRA)T. Morales Arizona Radiation Regulatory Agency (ARRA)

Enclosure Supplemental Information Regarding License Amendment Request toRevise Technical Specifications to Incorporate Updated Criticality Safety Analysis Enclosure Supplemental Information Regarding License Amendment Request to Revise Technical Specifications to Incorporate Updated Criticality Safety AnalysisIntroduction By letter dated November 25, 2015 (Agencywide Documents Access and Management System(ADAMS) Accession No. ML15336A251),

Arizona Public Service Company (APS) submitted alicense amendment request (LAR) for Palo Verde Nuclear Generating Station (PVNGS) Units 1,2, and 3. The proposed amendment would modify technical specification (TS) requirements toincorporate the results of an updated criticality safety analysis for both new and spent fuelstorage.The NRC staff reviewed the application and concluded that the information delineated below isnecessary to enable the staff to make an independent assessment regarding the acceptability ofthe proposed amendment.

Each of the NRC staff supplemental information requests is provided first, followed by the APSresponse to each request.NRC Staff Request Ia:In Section 4.3, "Significant Hazards Consideration,"

the licensee answers "No" to all threequestions.

a. In Question 1, please explain how the increased complexity of the spent fuel poolstorage requirements and the transitional period when two separate sets ofrequirements will be in place do not result in a significant increase in the probability of a fuel assembly misloading or justify your current answer. While there will beprocedures controlling the movement of fuel, the requirements will be more complexindicating the likelihood of an increased probability of a human error in creating thefuel handling move sheets.APS Response Ia:Although there is some increase in the complexity of TS 3.7.17 due to the increase in thenumber of allowable storage arrays, the proposed amendment does not significantly increasethe probability or consequences of an accident previously analyzed.

To address the additional arrays proposed in the LAR, the elements of the current process were reviewed.

Establishing the spent fuel pool layout is a procedurally controlled process performed by trained and qualified individuals and is a separate task from the generation of fuel movement sheets. Once theoverall spent fuel pool layout is confirmed it serves as the baseline for the subsequent spent fuelpool activities.

Each spent fuel pool layout is reviewed and independently verified to conform tothe array and cell interface requirements.

The fuel to be stored in the spent fuel pool is evaluated and is independently verified to classifyeach assembly with regard to initial enrichment, burnup, and other criteria to establish theregion specification for the spent fuel. The region specification establishes the appropriate region for each assembly.

This segregation of activities separates and insulates the complexity of spent fuel pool module geometry, fuel region specifications and interface considerations fromthe development of fuel movement sheets.1 Enclosure Supplemental Information Regarding License Amendment Request to Revise Technical Specifications to Incorporate Updated Criticality Safety AnalysisGeneration of fuel movement sheets is also a procedurally controlled process performed bytrained and qualified individuals, whether during the transition period or after the transition iscompleted.

Fuel movement sheets are generated to conform to the spent fuel pool layout that isdefined and independently verified to meet the fuel storage array requirements.

A human factors review was conducted in response to the NRC request for supplemental information.

The Standardized Plant Analysis Risk-Human Reliability Analysis (SPAR-H)method was chosen for the review since it is a recent methodology endorsed and used by theNRC. The Electric Power Research Institute (EPRI) Caused-Based Decision Tree Method(CBDTM) was also chosen since it is more-comprehensive and breaks the categories found inthe SPAR-H method into more specific categories.

None of the performance shaping factors (PSFs) from either the SPAR-H or CBDTMmethodologies identified significant potential impacts due to the process changes themselves orthe additional arrays. After reviewing the proposed changes to the process and complexity governing the movement of spent fuel, it is concluded there is no significant increase in theprobability of a fuel assembly misload event. The transition period was also reviewed including the fact that both the current and future spent fuel pool arrays will exist in the pool at the sametime.As a defense-in-depth measure to minimize the potential for an increase in the probability of amisload event during the transition phase, APS plans to have each fuel move sheet receive anadditional independent verification during the transition process.

In addition, APS does not planto perform other activities, such as dry cask loading or new fuel receipt during the spent fuelpool transition process for each spent fuel pool.The proposed amendment will not result in a significant increase in the probability of an accidentpreviously analyzed during the transition phase and future routine oper'ation.

The proposedamendment will not result in an increase in consequences of an accident previously analyzed asthe soluble boron concentration in the pool is almost 700 ppm above what is required tomaintain keff less than 0.95 during a postulated multiple misload accident.

The revised APS response to significant hazards considerations question 1 is provided inAttachment 1 to this Enclosure.

NRC Staff Request Ib:In Section 4.3, "Significant Hazards Consideration,"

the licensee answers "No" to all threequestions.

b. Section 5.6.5, "Inadvertent Removal of a SNAP-IN Insert,"

of Westinghouse ElectricCompany LLC's WCAP-18030-P, Revision 0, "Criticality Safety Analysis for PaloVerde Nuclear Generating

Station, Units 1, 2, and 3," September 2015, states, inpart, that "With the incorporation of SNAP-IN inserts, a new potential accident eventis created."

However, Question 2 of the Significant Hazards Consideration indicates there is no potential for a new or different accident than was previously analyzed.

Please revise the Significant Hazards Consideration or justify the current answer.2 Enclosure Supplemental Information Regarding License Amendment Request to Revise Technical Specifications to Incorporate Updated Criticality Safety AnalysisAPS Response Ib:WCAP-18030-P, Section 5.6.5, states "a new potential accident event is created."

This wasreferring to the removal of a SNAP-IN insert. The inadvertent removal of a SNAP-IN insertdoes not represent a "new or different kind of accident" as intended pursuant to the criteria of 10CFR 50.92. Rather, the removal of a SNAP-IN insert is an alternate way of creating a fuelassembly misload accident, which is an accident that is previously evaluated.

A misloadaccident occurs when there is a loss of configuration control and any portion of the spent fuelpool does not conform to an approved storage pattern, as identified in Sections 3.7.17 and4.3.1.1 of the Technical Specifications.

This loss of configuration control could manifest itself as:* A fuel assembly present in a location that is assumed to be empty* A location that requires a more restrictive combination of burnup/initial enrichment/decay time, or* A cell lacking a credited SNAP-IN insertThe inadvertent removal of a SNAP-IN insert is bounded by placing fuel in a location that thecriticality analysis requires to be empty (e.g., blocked).

These events are more consequential, as placing a fuel assembly in a vacant location has two effects.

First, the addition of fissilematerial increases the reactivity of the array. Second, soluble boron is displaced by the fuelassembly, further increasing the reactivity of the array.The inadvertent removal of a SNAP-IN insert has competing effects.

The removal of the SNAP-IN insert removes solid boron, increasing reactivity.

However, the removal of the SNAP-INinsert also slightly increases the amount of soluble boron in the array as the volume that wasoccupied with a SNAP-IN insert is replaced by borated water. The net reactivity effect of aninadvertent SNAP-IN insert removal is less than half the reactivity impact of misloading a fuelassembly into a cell required to be empty (e.g., blocked).

WCAP-18030-P includes technical evaluations for a single fuel assembly

misload, multiple fuelassembly

misloads, and inadvertent removal of a SNAP-IN insert. The results show that keffremains less than 0.95 crediting 1460 ppm boron for the multiple misload accident, 1100 ppmboron for the single misload accident and 450 ppm boron for the SNAP-IN insert removal.PVNGS TS 3.7,15, Fuel Storage Pool Boron Concentration, will remain unchanged at greaterthan or equal to 2150 ppm, providing additional margin to criticality.

The revised APS response to significant hazards considerations question 2 is provided inAttachment I to this Enclosure.

NRC Staff Request 2:The requirements for maintaining an adequate interface between different arrays is described inWCAP-18030-P, Section 5.3, "Interface Conditions" are not captured in the proposed technical specifications.

Please revise the proposed TSs to include the interface requirements or justifywhy interface conditions are not included in the TSs.3 Enclosure Supplemental Information Regarding License Amendment Request to Revise Technical Specifications to Incorporate Updated Criticality Safety AnalysisAPS Response 2:The LAR was originally developed with the expectation that the control of spent fuel pool layoutand interface requirements would be performed in accordance with updated plant implementing procedures, including specific training on the new requirements and updating job qualification cards. The specific nature of the interface requirements will be included in plant procedures, aspart of the implementation of the license amendment.

The current Standard Technical Specifications for Combustion Engineering Plants (NUREG-1432) does not specifically address this level of detail in Sections 3.7.18 or Section 4.3, FuelStorage.

However, in light of the NRC staff supplemental

request, APS is adding the following note to Technical Specification Figure 3.7.17-1:

"Interface requirements:

Each cell is part of up to four 2x2 arrays and each cellmust simultaneously meet the requirements of all those arrays of which it is apart."Adding this note to the TS is consistent with the interface condition identified in WCAP-18030-P.

The affected TS markup page is provided as Attachment 2 to this Enclosure and the clean TS page is provided as Attachment 3 to this Enclosure.

NRC Staff Request 3:Please provide the analysis supporting the modeling of fuel assembly grids and spacersdiscussed in WCAP-18030-P, Section 5.1.2.3, "Grid and Sleeves."

APS Response 3:An expanded description of the basis for the conclusion in WCAP-1 8030-P, Section 5.1.2.3, isprovided in Westinghouse Criticality

Topical, WCAP-17483-P, Section 4.2.3, which explicitly includes the APS limiting assembly (CE 16X16 NGF) type. WCAP-1 7483-P was provided to theNRC in Westinghouse letter LTR-NRC-1 1-71, Submittal of WCA P-I17483-P, Revision 0 andWCA P-I17483-NP, Revision 0, Westinghouse Methodology for Spent Fuel Pool and New FuelRack Criticality Safety Analysis, on December 20, 2011. The letter is retrievable in ADAMS asMLII1364A065.

The non-proprietary version of WCAP-1 7483-NP is retrievable in ADAMS asMLII364A066.

The fuel assembly grid and spacer modeling provided in these WCAPs is similarto other licensees that have been accepted for review and approved as license amendments.

4 Enclosure Supplemental Information Regarding License Amendment Request to Revise Technical Specifications to Incorporate Updated Criticality Safety AnalysisATTACHMENT 1Revised Significant Hazards Consideration Responses Questions 1 and 25 Enclosure Supplemental Information Regarding License Amendment Request to Revise Technical Specifications to Incorporate Updated Criticality Safety AnalysisAttachment 1Revised Significant Hazards Consideration Responses for Questions 1 and 2(Changes identified with vertical bars in the right margin)Significant Hazards Consideration As required by 10 CFR 50.91 (a), Notice for Public Comment, an analysis of the issue of nosignificant hazards consideration using the standards in 10 CFR 50.92,/Issuance ofAmendment, is presented below:1. Does the proposed amendment involve a significant increase in the probability orconsequences of an accident previously evaluated?

Response:

No.The proposed amendment would modify the Palo Verde Nuclear Generating Station(PVNGS) Technical Specifications (TS) to incorporate the results of an updated criticality safety analysis for both new fuel and spent fuel storage.

The revised criticality safetyanalysis provides an updated methodology that allows credit for neutron absorbing NETCO-SNAP-IN rack inserts and corrects non-conservative input assumptions in the previouscriticality safety analysis.

The proposed amendment does not change or modify the fuel, fuel handling processes, number of fuel assemblies that may be stored in the spent fuel pool (SFP), decay heatgeneration rate, or the SEP cooling and cleanup system. The proposed amendment wasevaluated for impact on the following previously evaluated events and accidents:

• fuel handling accident (FHA)* fuel misload event* SEP boron dilution event* seismic event* loss of SEP cooling eventImplementation of the proposed amendment will be accomplished in accordance with theSpent Fuel Pool Transition Plan and does not involve new fuel handling equipment orprocesses.

The radiological source term of the fuel assemblies is not affected by theproposed amendment request.

The FHA radiological dose consequences associated withfuel enrichment at this level are addressed in the PVNGS Updated Final Safety AnalysisReport (UFSAR) Section 15.7.4 and remain unchanged.

Therefore, the proposedamendments do not significantly increase the probability or consequences of a FHA.To address the proposed additional arrays, several elements of the current process werereviewed.

Pool layout, region eligibility specifications and the development of fuel movesheets are separate tasks. Each of these activities is procedurally controlled and performed by trained and qualified individuals.

This segregation of activities separates and insulates 6

Enclosure Supplemental Information Regarding License Amendment Request to Revise Technical Specifications to Incorporate Updated Criticality Safety Analysisthe complexity of spent fuel pool module geometry, fuel region specifications and interface considerations from the development of fuel movement sheets.Creation of fuel move sheets in accordance with the proposed amendment will notsignificantly change the probability of a fuel misload event because development of fuelmove sheets will continue to be controlled by approved procedures and developed byqualified personnel.

A review of the additional proposed arrays and the transitional period(when both the current and new arrays would be effective in the spent fuel pool) wasperformed.

The human performance shaping factors evaluated did not identify significant potential impacts due to the process changes themselves or the additional arrays. Thereview, therefore, confirmed that the potential for human performance errors resulting in theprobability of a misload event is not significantly increased.

Operation in accordance with the proposed amendment will not significantly change theprobability of a fuel misload event because fuel movement activities will continue to becontrolled by approved fuel handling procedures and performed by qualified personnel.

Although there will be additional allowable storage arrays defined by the amendment, thefuel handling procedures will continue to require identification of the initial and targetlocations for each fuel assembly that is moved.The consequences of a fuel misload event are not changed because the reactivity analysisdemonstrates that the same subcriticality criteria and requirements continue to be met forthe limiting fuel misload event.Operation in accordance with the proposed amendment will not change the probability orconsequences of a boron dilution event because the systems and events that could affectSEP soluble boron concentration are unchanged.

The current boron dilution analysisdemonstrates that the limiting boron dilution event will reduce the boron concentration fromthe TS limit of 2150 ppm to 1900 ppm. This leaves sufficient margin to the 1460 ppmcredited by the SEP criticality safety analysis.

The analysis confirms that the time needed fordilution to reduce the soluble boron concentration is greater than the time needed for actionsto be taken to prevent further dilution.

Operation in accordance with the proposed amendment will not change the probability of aseismic event since there are no elements of the updated criticality analysis that influence the occurrence of a seismic event. The consequences of a seismic event are notsignificantly increased because the forcing functions for seismic excitation are not increased and because the mass of storage racks with NETCO-SNAP-IN inserts is not appreciably increased.

Seismic analyses demonstrate adequate stress levels in the storage racks wheninserts are installed.

Operation in accordance with the proposed amendment will not change the probability of aloss of SEP cooling event because the systems and events that could affect SEP cooling areunchanged.

The consequences are not significantly increased because there are nochanges in the SEP heat load or SEP cooling systems, structures, or components.

Eurthermore, conservative analyses indicate that the current design requirements andcriteria continue to be met with the NETCO-SNAP-lN inserts installed.

7 Enclosure Supplemental Information Regarding License Amendment Request to Revise Technical Specifications to Incorporate Updated Criticality Safety AnalysisTherefore, the proposed amendment does not involve a significant increase in theprobability or consequences of an accident previously evaluated.

2. Does the proposed amendment create the possibility of a new or different kind ofaccident from any accident previously evaluated?

Response:

No.The proposed amendment would modify the PVNGS TS to incorporate the results of anupdated criticality safety analysis for both new fuel and spent fuel storage.

The revisedcriticality safety analysis provides an updated methodology that allows credit for neutronabsorbing NETCO-SNAP-IN rack inserts and corrects non-conservative input assumptions in the previous criticality safety analysis.

The proposed amendment does not change or modify the fuel, fuel handling processes, number of fuel assemblies that may be stored in the pool, decay heat generation rate, or theSFP cooling and cleanup system. The effects of operating with the proposed amendment are listed below. The proposed amendment was evaluated for the potential of each effect tocreate the possibility of a new or different kind of accident:

• addition of inserts to the SFP storage racks* new storage patterns* additional weight from the inserts* displacement of SFP water by the inserts,Each NETCO-SNAP-IN insert will be placed between a fuel assembly and the storage cellwall, taking up some of the space available on two sides of the fuel assembly.

Analysesdemonstrate that the presence of the inserts does not adversely affect spent fuel cooling,seismic capability, or subcriticality.

The aluminum and boron carbide materials ofconstruction have been shown to be compatible with nuclear fuel, storage racks, and SFPenvironments, and generate no adverse material interactions.

Therefore, placing the insertsinto the SFP storage racks cannot cause a new or different kind of accident.

Operation with the added weight of the NETCO-SNAP-IN inserts will not create a new ordifferent accident.

The analyses of the racks with NETCO-SNAP-IN inserts installed demonstrate that the stress levels in the rack modules continue to be considerably less thanallowable stress limits. Therefore, the added weight from the inserts cannot cause a new ordifferent kind of accident.

Operation with the proposed fuel storage patterns will not create a new or different kind ofaccident because fuel movement will continue to be controlled by approved fuel handlingprocedures.

These procedures continue to require identification of the initial and targetlocations for each fuel assembly that is moved. There are no changes in the criteria ordesign requirements pertaining to fuel storage safety, including subcriticality requirements.

Analyses demonstrate that the proposed storage patterns meet these requirements andcriteria with adequate margins.

Therefore, the proposed storage patterns cannot cause anew or different kind of accident.

8 Enclosure Supplemental Information Regarding License Amendment Request to Revise Technical Specifications to Incorporate Updated Criticality Safety AnalysisThe scenario involving the inadvertent removal of a SNAP-IN insert was evaluated andfound to not represent a "new or different kind of accident."

Rather, it represents a loss ofreactivity configuration

control, which is a less significant form of a fuel assembly misloadevent. Whenever a fuel assembly is placed in a storage configuration that is not explicitly

allowed, a fuel assembly misload condition is created, whether it is the removal of a SNAP-IN insert or the placement of a fuel assembly in a location that is missing a specified SNAP-IN insert. An inadvertent removal of a SNAP-IN insert is, therefore, not a new kind ofaccident but rather an alternate way of creating a previously evaluated accident.

Loading afuel assembly into a storage cell location required to be vacant and blocked (the limitingaccident of this type) bounds the removal of a SNAP-IN insert.Operation with insert movement above stored fuel will not create a new or different kind ofaccident.

The insert with its handling tool weighs less than the weight of a single fuelassembly.

Single fuel assemblies are routinely moved safely over fuel assemblies and thesame level of safety in design and operation will be maintained when moving the inserts.The installed rack inserts will displace a negligible quantity of the SEP water volume andtherefore will not reduce operator response time to previously-evaluated SEP accidents.

The accidents and events previously analyzed remain bounding.

Therefore, the proposedamendment does not create the possibility of a new or different kind of accident from anyaccident previously evaluated.

9 Enclosure Supplemental Information Regarding License Amendment Request to Revise Technical Specifications to Incorporate Updated Criticality Safety AnalysisATTACHMENT 2Marked-up Technical Specifications Page(Page Provided for After SFP Transition)

Revisedinsert pagerelated to3.7.17-2(Figure3.7.17-1)

SAfter SFP transition Spent Fuel Assembly Storage3.7.17Figure 3.7.17-1Allowable Storage ArraysArray A Two Region 1 assemblies (1) checkerboarded With two blocked cells (X). The Region ........1 assemblies are each in a cell with a stainless steel L-insert.

No NETCO-SNAP-INa insertsare credited.

X Array B Two Region 1 assemblies (1) checkerboarded with two cells containing trash cans (TC). The Region 1 assemblies are each in a cell with a stainless steel L-insert.

Every ': cell without a stainless steel L-insert must contain a NETCO-SNAP-1N insert. TC

.Array Two Region 2 assemblies (2) checkerboarded with one Region 3 assembly (3) and i:,.i;i[i" one blocked cell (X). The Region 2 assemblies are each in a cell with a stainless steel L-insert.

The Region 3 assembly is in a cell containing a

insert. 3 2::OeRegion 2assembly (2) checkerboarded with three Region 4 assemblies (4). T heRegion 2 assembly and the diagonally located Region 4 assembly are each in a storage cell with a stainless steel L-insert.

The two storage cells without a stainless 4

steel L-insert contain a NETCO-SNAP-IN insert.Array E Four Region 5 assemblies (5). Two storage cells contain a stainless steel L-insert.

Onecell contains a

insert. One storage cell contains no insert. "

.,.Four Region 6 assemblies (6). Two storage cells contain a stainless steel L-insert.

The... .-.,other two cells contain no inserts.

Nolte..s:l. The shaded locations indicate cells which contain a stainless steel L-insert.

2. A blocked cell (X) contains a blocking device and only water in the active fuel region.3. NETCO-SNAP-IN inserts must be oriented in the same direction as the stainless steel L-inserts.

4.

inserts are ~only located in cells without a stainless steel L-insert.

5. Any cell containing a fuel assembly or a TC may instead be an empty (water-filled) cell in allstorage arrays.6. Any storage array location designated for a fuel assembly may be replaced with non-fissile material.

Enclosure Supplemental Information Regarding License Amendment Request to Revise Technical Specifications to Incorporate Updated Criticality Safety AnalysisATTACHMENT 3Revised Technical Specifications Page (Clean Copy)(Page Provided for After SFP Transition) 3.7.17-7 After SFP transition Spent Fuel Assembly Storage3.7.17Figure 3.7.17-1A11lowabl e Storaae ArraysArra A 1 XTwo Region 1 assemblies (1) checkerboarded with two blocked cells (X). :i.i7The Region 1 assemblies are each in a cell with a stainless steel X *:7 !L-insert.

No NETCO-SNAP-IN inserts are credited.

Array B ..... TWO Region 1 assemblies (1) checkerboarded with two cells containing trash cans (TC). The Region 1 assemblies are each in a cell with a -

stainless steel L-insert.

Every cell without a stainless steel L- TC insert must contain a NETCO-SNAP-IN insert. Two Region 2 assemblies (2) checkerboarded with one Region 3 assembly(3) and one blocked cell (X). The Region 2 assemblies are each in a cell with a stainless steel L-insert.

The Region 3 assembly is in a 3 cell containing a NETCO-SNAP-IN insert.Array D '< One Region 2 assembly (2) checkerboarded with three Region 4 4assemblies (4). The Region 2 assembly and the diagonally locatedRegion 4 assembly are each in a storage cell with a stainless steel L- insert. The two storage cells without a stainless steel L-insert 4

contain a NETCO-SNAP-IN insert.Array E 5Four Region 5 assemblies (5). Two storage cells contain a stainless 1'!LM:steel L-insert.

One cell contains a NETCO-SNAP-IN insert. One storage cell contains no insert.

Array F 6Four Region 6 assemblies (6). Two storage cells contain a stainless steel L-insert.

The other two cells contain no inserts.

6 Notes:1. The shaded locations indicate cells which contain a stainless steel L-insert*

2. A blocked cell (X) contains a blocking device and only water in the active fuel region.3. NETCO-SNAP-IN inserts must be oriented in the same direction as the stainless steel L-inserts.

4. NETCO-SNAP-IN inserts are only located in cells without a stainless steel L-insert.

5. Any cell containing a fuel assembly or a TC may instead be an empty (water-filled) cell in all storagearrays.6. Any storage array location designated for a fuel assembly may be replaced with non-fissile material.

7. Interface requirements:

Each cell is part of up to four 2x2 arrays and each cell must simultaneously meet the requirements of all those arrays of which it is a part,PALO VERDE UNITS 1,2,3 371- MNMN O3.7.17-7AMENDMENT NO.

10 CFR 50.90Maria L. LacalVice President, NuclearRegulatory

& Oversight OapsPalo VerdeNuclear Generating StationP.O. Box 52034Phoenix, AZ 85072Mail Station 7605Tel 623.393.6491 102-07181-MLL/TNW January 29, 2016U. S. Nuclear Regulatory Commission ATTN: Document Control DeskWashington, DC 20555-0001

References:

1. Arizona Public Service Company (APS) letter number 102-07149, License Amendment Request to Revise Technical Specifications toIncorporate Updated Criticality Safety Analysis, dated November 25,2015, [Agencywide Documents Access and Management System(ADAMS) Accession Number M L15336A25 1]2. NRC letter Palo Verde Nuclear Generating

Station, Units 1, 2, and 3 -Supplemental In formation Needed for Acceptance of Requested Licensing Action Re: License Amendment Request to Revise Technical Specifications to Incorporate Updated Criticality Safety Analysis, datedJanuary 15, 2016 (ADAMS Accession No. ML16014A001)

Palo Verde Nuclear Generating Station (PVNGS)Units 1, 2, and 3Docket Nos. STN 50-528, 50-529, and 50-530Supplemental Information Regarding License Amendment Request toRevise Technical Specifications to Incorporate Updated Criticality Safety Analysis

Subject:

In reference 1, Arizona Public Service Company (APS) submitted a license amendment request (LAR) to revise the PVNGS Technical Specifications (TS) for Palo Verde NuclearGenerating Station (PVNGS) Units 1, 2, and 3. The proposed amendment would modify TSrequirements to incorporate the results of an updated criticality safety analysis for both newand spent fuel storage.

In reference 2, the Nuclear Regulatory Commission (NRC) staffrequested supplemental information to support the acceptance review of the LAR.The enclosure to this letter provides supplemental information in response to the NRCrequest.

The enclosure also contains three attachments.

Attachment 1 provides the revisedAPS response to significant hazards consideration questions 1 and 2. The original APSresponse to question 3 of the significant hazards consideration remains unchanged.

Attachment 2 provides a marked-up TS page that includes the requested information regarding interface requirements mentioned in NRC supplemental information requestnumber 2. Attachment 3 provides the revised (clean) TS page.This submittal does not contain any new regulatory commitments as defined by NEI 99-04,Guidelines for Managing NRC Commitment

Changes, Revision 0.A memb~er of the STAR (Strategic Teaming and Resource Sharing)

Alliance Clwy DiboCno PaoVerd WolfCre 102-07181

-MLL/TNWATTN: Document Control DeskU. S. Nuclear Regulatory Commission Supplemental Information Regarding License Amendment Request to Revise Technical Specifications to Incorporate Updated Criticality Safety AnalysisPage 2In accordance with the PVNGS Quality Assurance

Program, the Plant Review Board and theOffsite Safety Review Committee have reviewed and approved the proposed changes to theLAR. By copy of this letter, this change to the LAR is being forwarded to the ArizonaRadiation Regulatory Agency in accordance with 10 CFR 50.9 1(b)(1).Should you have any questions concerning the content of this letter, please contact ThomasWeber, Department Leader, Nuclear Regulatory

Affairs, at (623) 393-5764.

I declare under penalty of perjury that the foregoing is true and correct.Executed on: January 29, 2016(Date)Sincerely, IiDigitally signed by Andrews, GeorgeAnd rews, George Dgcgn=Andrews, GeorgeW(978

%AlIT(t'3-1 am approving this documentW L /' =I'R' delegated for Maria Lacal./J Date: 2016.01.29 14:44:37

-07'00'MLL/TNW/CJS/af

Enclosure:

Supplemental Information Regarding License Amendment Request to ReviseTechnical Specifications to Incorporate Updated Criticality Safety Analysiscc: M. L. Dapas NRC Region IV Regional Administrator

• M. M. Watford NRC NRR Project Manager for PVNGSL. J. KIos NRC NRR Project ManagerC. A. Peabody NRC Senior Resident Inspector for PVNGSA. V. Godwin Arizona Radiation Regulatory Agency (ARRA)T. Morales Arizona Radiation Regulatory Agency (ARRA)

Enclosure Supplemental Information Regarding License Amendment Request toRevise Technical Specifications to Incorporate Updated Criticality Safety Analysis Enclosure Supplemental Information Regarding License Amendment Request to Revise Technical Specifications to Incorporate Updated Criticality Safety AnalysisIntroduction By letter dated November 25, 2015 (Agencywide Documents Access and Management System(ADAMS) Accession No. ML15336A251),

Arizona Public Service Company (APS) submitted alicense amendment request (LAR) for Palo Verde Nuclear Generating Station (PVNGS) Units 1,2, and 3. The proposed amendment would modify technical specification (TS) requirements toincorporate the results of an updated criticality safety analysis for both new and spent fuelstorage.The NRC staff reviewed the application and concluded that the information delineated below isnecessary to enable the staff to make an independent assessment regarding the acceptability ofthe proposed amendment.

Each of the NRC staff supplemental information requests is provided first, followed by the APSresponse to each request.NRC Staff Request Ia:In Section 4.3, "Significant Hazards Consideration,"

the licensee answers "No" to all threequestions.

a. In Question 1, please explain how the increased complexity of the spent fuel poolstorage requirements and the transitional period when two separate sets ofrequirements will be in place do not result in a significant increase in the probability of a fuel assembly misloading or justify your current answer. While there will beprocedures controlling the movement of fuel, the requirements will be more complexindicating the likelihood of an increased probability of a human error in creating thefuel handling move sheets.APS Response Ia:Although there is some increase in the complexity of TS 3.7.17 due to the increase in thenumber of allowable storage arrays, the proposed amendment does not significantly increasethe probability or consequences of an accident previously analyzed.

To address the additional arrays proposed in the LAR, the elements of the current process were reviewed.

Establishing the spent fuel pool layout is a procedurally controlled process performed by trained and qualified individuals and is a separate task from the generation of fuel movement sheets. Once theoverall spent fuel pool layout is confirmed it serves as the baseline for the subsequent spent fuelpool activities.

Each spent fuel pool layout is reviewed and independently verified to conform tothe array and cell interface requirements.

The fuel to be stored in the spent fuel pool is evaluated and is independently verified to classifyeach assembly with regard to initial enrichment, burnup, and other criteria to establish theregion specification for the spent fuel. The region specification establishes the appropriate region for each assembly.

This segregation of activities separates and insulates the complexity of spent fuel pool module geometry, fuel region specifications and interface considerations fromthe development of fuel movement sheets.1 Enclosure Supplemental Information Regarding License Amendment Request to Revise Technical Specifications to Incorporate Updated Criticality Safety AnalysisGeneration of fuel movement sheets is also a procedurally controlled process performed bytrained and qualified individuals, whether during the transition period or after the transition iscompleted.

Fuel movement sheets are generated to conform to the spent fuel pool layout that isdefined and independently verified to meet the fuel storage array requirements.

A human factors review was conducted in response to the NRC request for supplemental information.

The Standardized Plant Analysis Risk-Human Reliability Analysis (SPAR-H)method was chosen for the review since it is a recent methodology endorsed and used by theNRC. The Electric Power Research Institute (EPRI) Caused-Based Decision Tree Method(CBDTM) was also chosen since it is more-comprehensive and breaks the categories found inthe SPAR-H method into more specific categories.

None of the performance shaping factors (PSFs) from either the SPAR-H or CBDTMmethodologies identified significant potential impacts due to the process changes themselves orthe additional arrays. After reviewing the proposed changes to the process and complexity governing the movement of spent fuel, it is concluded there is no significant increase in theprobability of a fuel assembly misload event. The transition period was also reviewed including the fact that both the current and future spent fuel pool arrays will exist in the pool at the sametime.As a defense-in-depth measure to minimize the potential for an increase in the probability of amisload event during the transition phase, APS plans to have each fuel move sheet receive anadditional independent verification during the transition process.

In addition, APS does not planto perform other activities, such as dry cask loading or new fuel receipt during the spent fuelpool transition process for each spent fuel pool.The proposed amendment will not result in a significant increase in the probability of an accidentpreviously analyzed during the transition phase and future routine oper'ation.

The proposedamendment will not result in an increase in consequences of an accident previously analyzed asthe soluble boron concentration in the pool is almost 700 ppm above what is required tomaintain keff less than 0.95 during a postulated multiple misload accident.

The revised APS response to significant hazards considerations question 1 is provided inAttachment 1 to this Enclosure.

NRC Staff Request Ib:In Section 4.3, "Significant Hazards Consideration,"

the licensee answers "No" to all threequestions.

b. Section 5.6.5, "Inadvertent Removal of a SNAP-IN Insert,"

of Westinghouse ElectricCompany LLC's WCAP-18030-P, Revision 0, "Criticality Safety Analysis for PaloVerde Nuclear Generating

Station, Units 1, 2, and 3," September 2015, states, inpart, that "With the incorporation of SNAP-IN inserts, a new potential accident eventis created."

However, Question 2 of the Significant Hazards Consideration indicates there is no potential for a new or different accident than was previously analyzed.

Please revise the Significant Hazards Consideration or justify the current answer.2 Enclosure Supplemental Information Regarding License Amendment Request to Revise Technical Specifications to Incorporate Updated Criticality Safety AnalysisAPS Response Ib:WCAP-18030-P, Section 5.6.5, states "a new potential accident event is created."

This wasreferring to the removal of a SNAP-IN insert. The inadvertent removal of a SNAP-IN insertdoes not represent a "new or different kind of accident" as intended pursuant to the criteria of 10CFR 50.92. Rather, the removal of a SNAP-IN insert is an alternate way of creating a fuelassembly misload accident, which is an accident that is previously evaluated.

A misloadaccident occurs when there is a loss of configuration control and any portion of the spent fuelpool does not conform to an approved storage pattern, as identified in Sections 3.7.17 and4.3.1.1 of the Technical Specifications.

This loss of configuration control could manifest itself as:* A fuel assembly present in a location that is assumed to be empty* A location that requires a more restrictive combination of burnup/initial enrichment/decay time, or* A cell lacking a credited SNAP-IN insertThe inadvertent removal of a SNAP-IN insert is bounded by placing fuel in a location that thecriticality analysis requires to be empty (e.g., blocked).

These events are more consequential, as placing a fuel assembly in a vacant location has two effects.

First, the addition of fissilematerial increases the reactivity of the array. Second, soluble boron is displaced by the fuelassembly, further increasing the reactivity of the array.The inadvertent removal of a SNAP-IN insert has competing effects.

The removal of the SNAP-IN insert removes solid boron, increasing reactivity.

However, the removal of the SNAP-INinsert also slightly increases the amount of soluble boron in the array as the volume that wasoccupied with a SNAP-IN insert is replaced by borated water. The net reactivity effect of aninadvertent SNAP-IN insert removal is less than half the reactivity impact of misloading a fuelassembly into a cell required to be empty (e.g., blocked).

WCAP-18030-P includes technical evaluations for a single fuel assembly

misload, multiple fuelassembly

misloads, and inadvertent removal of a SNAP-IN insert. The results show that keffremains less than 0.95 crediting 1460 ppm boron for the multiple misload accident, 1100 ppmboron for the single misload accident and 450 ppm boron for the SNAP-IN insert removal.PVNGS TS 3.7,15, Fuel Storage Pool Boron Concentration, will remain unchanged at greaterthan or equal to 2150 ppm, providing additional margin to criticality.

The revised APS response to significant hazards considerations question 2 is provided inAttachment I to this Enclosure.

NRC Staff Request 2:The requirements for maintaining an adequate interface between different arrays is described inWCAP-18030-P, Section 5.3, "Interface Conditions" are not captured in the proposed technical specifications.

Please revise the proposed TSs to include the interface requirements or justifywhy interface conditions are not included in the TSs.3 Enclosure Supplemental Information Regarding License Amendment Request to Revise Technical Specifications to Incorporate Updated Criticality Safety AnalysisAPS Response 2:The LAR was originally developed with the expectation that the control of spent fuel pool layoutand interface requirements would be performed in accordance with updated plant implementing procedures, including specific training on the new requirements and updating job qualification cards. The specific nature of the interface requirements will be included in plant procedures, aspart of the implementation of the license amendment.

The current Standard Technical Specifications for Combustion Engineering Plants (NUREG-1432) does not specifically address this level of detail in Sections 3.7.18 or Section 4.3, FuelStorage.

However, in light of the NRC staff supplemental

request, APS is adding the following note to Technical Specification Figure 3.7.17-1:

"Interface requirements:

Each cell is part of up to four 2x2 arrays and each cellmust simultaneously meet the requirements of all those arrays of which it is apart."Adding this note to the TS is consistent with the interface condition identified in WCAP-18030-P.

The affected TS markup page is provided as Attachment 2 to this Enclosure and the clean TS page is provided as Attachment 3 to this Enclosure.

NRC Staff Request 3:Please provide the analysis supporting the modeling of fuel assembly grids and spacersdiscussed in WCAP-18030-P, Section 5.1.2.3, "Grid and Sleeves."

APS Response 3:An expanded description of the basis for the conclusion in WCAP-1 8030-P, Section 5.1.2.3, isprovided in Westinghouse Criticality

Topical, WCAP-17483-P, Section 4.2.3, which explicitly includes the APS limiting assembly (CE 16X16 NGF) type. WCAP-1 7483-P was provided to theNRC in Westinghouse letter LTR-NRC-1 1-71, Submittal of WCA P-I17483-P, Revision 0 andWCA P-I17483-NP, Revision 0, Westinghouse Methodology for Spent Fuel Pool and New FuelRack Criticality Safety Analysis, on December 20, 2011. The letter is retrievable in ADAMS asMLII1364A065.

The non-proprietary version of WCAP-1 7483-NP is retrievable in ADAMS asMLII364A066.

The fuel assembly grid and spacer modeling provided in these WCAPs is similarto other licensees that have been accepted for review and approved as license amendments.

4 Enclosure Supplemental Information Regarding License Amendment Request to Revise Technical Specifications to Incorporate Updated Criticality Safety AnalysisATTACHMENT 1Revised Significant Hazards Consideration Responses Questions 1 and 25 Enclosure Supplemental Information Regarding License Amendment Request to Revise Technical Specifications to Incorporate Updated Criticality Safety AnalysisAttachment 1Revised Significant Hazards Consideration Responses for Questions 1 and 2(Changes identified with vertical bars in the right margin)Significant Hazards Consideration As required by 10 CFR 50.91 (a), Notice for Public Comment, an analysis of the issue of nosignificant hazards consideration using the standards in 10 CFR 50.92,/Issuance ofAmendment, is presented below:1. Does the proposed amendment involve a significant increase in the probability orconsequences of an accident previously evaluated?

Response:

No.The proposed amendment would modify the Palo Verde Nuclear Generating Station(PVNGS) Technical Specifications (TS) to incorporate the results of an updated criticality safety analysis for both new fuel and spent fuel storage.

The revised criticality safetyanalysis provides an updated methodology that allows credit for neutron absorbing NETCO-SNAP-IN rack inserts and corrects non-conservative input assumptions in the previouscriticality safety analysis.

The proposed amendment does not change or modify the fuel, fuel handling processes, number of fuel assemblies that may be stored in the spent fuel pool (SFP), decay heatgeneration rate, or the SEP cooling and cleanup system. The proposed amendment wasevaluated for impact on the following previously evaluated events and accidents:

• fuel handling accident (FHA)* fuel misload event* SEP boron dilution event* seismic event* loss of SEP cooling eventImplementation of the proposed amendment will be accomplished in accordance with theSpent Fuel Pool Transition Plan and does not involve new fuel handling equipment orprocesses.

The radiological source term of the fuel assemblies is not affected by theproposed amendment request.

The FHA radiological dose consequences associated withfuel enrichment at this level are addressed in the PVNGS Updated Final Safety AnalysisReport (UFSAR) Section 15.7.4 and remain unchanged.

Therefore, the proposedamendments do not significantly increase the probability or consequences of a FHA.To address the proposed additional arrays, several elements of the current process werereviewed.

Pool layout, region eligibility specifications and the development of fuel movesheets are separate tasks. Each of these activities is procedurally controlled and performed by trained and qualified individuals.

This segregation of activities separates and insulates 6

Enclosure Supplemental Information Regarding License Amendment Request to Revise Technical Specifications to Incorporate Updated Criticality Safety Analysisthe complexity of spent fuel pool module geometry, fuel region specifications and interface considerations from the development of fuel movement sheets.Creation of fuel move sheets in accordance with the proposed amendment will notsignificantly change the probability of a fuel misload event because development of fuelmove sheets will continue to be controlled by approved procedures and developed byqualified personnel.

A review of the additional proposed arrays and the transitional period(when both the current and new arrays would be effective in the spent fuel pool) wasperformed.

The human performance shaping factors evaluated did not identify significant potential impacts due to the process changes themselves or the additional arrays. Thereview, therefore, confirmed that the potential for human performance errors resulting in theprobability of a misload event is not significantly increased.

Operation in accordance with the proposed amendment will not significantly change theprobability of a fuel misload event because fuel movement activities will continue to becontrolled by approved fuel handling procedures and performed by qualified personnel.

Although there will be additional allowable storage arrays defined by the amendment, thefuel handling procedures will continue to require identification of the initial and targetlocations for each fuel assembly that is moved.The consequences of a fuel misload event are not changed because the reactivity analysisdemonstrates that the same subcriticality criteria and requirements continue to be met forthe limiting fuel misload event.Operation in accordance with the proposed amendment will not change the probability orconsequences of a boron dilution event because the systems and events that could affectSEP soluble boron concentration are unchanged.

The current boron dilution analysisdemonstrates that the limiting boron dilution event will reduce the boron concentration fromthe TS limit of 2150 ppm to 1900 ppm. This leaves sufficient margin to the 1460 ppmcredited by the SEP criticality safety analysis.

The analysis confirms that the time needed fordilution to reduce the soluble boron concentration is greater than the time needed for actionsto be taken to prevent further dilution.

Operation in accordance with the proposed amendment will not change the probability of aseismic event since there are no elements of the updated criticality analysis that influence the occurrence of a seismic event. The consequences of a seismic event are notsignificantly increased because the forcing functions for seismic excitation are not increased and because the mass of storage racks with NETCO-SNAP-IN inserts is not appreciably increased.

Seismic analyses demonstrate adequate stress levels in the storage racks wheninserts are installed.

Operation in accordance with the proposed amendment will not change the probability of aloss of SEP cooling event because the systems and events that could affect SEP cooling areunchanged.

The consequences are not significantly increased because there are nochanges in the SEP heat load or SEP cooling systems, structures, or components.

Eurthermore, conservative analyses indicate that the current design requirements andcriteria continue to be met with the NETCO-SNAP-lN inserts installed.

7 Enclosure Supplemental Information Regarding License Amendment Request to Revise Technical Specifications to Incorporate Updated Criticality Safety AnalysisTherefore, the proposed amendment does not involve a significant increase in theprobability or consequences of an accident previously evaluated.

2. Does the proposed amendment create the possibility of a new or different kind ofaccident from any accident previously evaluated?

Response:

No.The proposed amendment would modify the PVNGS TS to incorporate the results of anupdated criticality safety analysis for both new fuel and spent fuel storage.

The revisedcriticality safety analysis provides an updated methodology that allows credit for neutronabsorbing NETCO-SNAP-IN rack inserts and corrects non-conservative input assumptions in the previous criticality safety analysis.

The proposed amendment does not change or modify the fuel, fuel handling processes, number of fuel assemblies that may be stored in the pool, decay heat generation rate, or theSFP cooling and cleanup system. The effects of operating with the proposed amendment are listed below. The proposed amendment was evaluated for the potential of each effect tocreate the possibility of a new or different kind of accident:

• addition of inserts to the SFP storage racks* new storage patterns* additional weight from the inserts* displacement of SFP water by the inserts,Each NETCO-SNAP-IN insert will be placed between a fuel assembly and the storage cellwall, taking up some of the space available on two sides of the fuel assembly.

Analysesdemonstrate that the presence of the inserts does not adversely affect spent fuel cooling,seismic capability, or subcriticality.

The aluminum and boron carbide materials ofconstruction have been shown to be compatible with nuclear fuel, storage racks, and SFPenvironments, and generate no adverse material interactions.

Therefore, placing the insertsinto the SFP storage racks cannot cause a new or different kind of accident.

Operation with the added weight of the NETCO-SNAP-IN inserts will not create a new ordifferent accident.

The analyses of the racks with NETCO-SNAP-IN inserts installed demonstrate that the stress levels in the rack modules continue to be considerably less thanallowable stress limits. Therefore, the added weight from the inserts cannot cause a new ordifferent kind of accident.

Operation with the proposed fuel storage patterns will not create a new or different kind ofaccident because fuel movement will continue to be controlled by approved fuel handlingprocedures.

These procedures continue to require identification of the initial and targetlocations for each fuel assembly that is moved. There are no changes in the criteria ordesign requirements pertaining to fuel storage safety, including subcriticality requirements.

Analyses demonstrate that the proposed storage patterns meet these requirements andcriteria with adequate margins.

Therefore, the proposed storage patterns cannot cause anew or different kind of accident.

8 Enclosure Supplemental Information Regarding License Amendment Request to Revise Technical Specifications to Incorporate Updated Criticality Safety AnalysisThe scenario involving the inadvertent removal of a SNAP-IN insert was evaluated andfound to not represent a "new or different kind of accident."

Rather, it represents a loss ofreactivity configuration

control, which is a less significant form of a fuel assembly misloadevent. Whenever a fuel assembly is placed in a storage configuration that is not explicitly

allowed, a fuel assembly misload condition is created, whether it is the removal of a SNAP-IN insert or the placement of a fuel assembly in a location that is missing a specified SNAP-IN insert. An inadvertent removal of a SNAP-IN insert is, therefore, not a new kind ofaccident but rather an alternate way of creating a previously evaluated accident.

Loading afuel assembly into a storage cell location required to be vacant and blocked (the limitingaccident of this type) bounds the removal of a SNAP-IN insert.Operation with insert movement above stored fuel will not create a new or different kind ofaccident.

The insert with its handling tool weighs less than the weight of a single fuelassembly.

Single fuel assemblies are routinely moved safely over fuel assemblies and thesame level of safety in design and operation will be maintained when moving the inserts.The installed rack inserts will displace a negligible quantity of the SEP water volume andtherefore will not reduce operator response time to previously-evaluated SEP accidents.

The accidents and events previously analyzed remain bounding.

Therefore, the proposedamendment does not create the possibility of a new or different kind of accident from anyaccident previously evaluated.

9 Enclosure Supplemental Information Regarding License Amendment Request to Revise Technical Specifications to Incorporate Updated Criticality Safety AnalysisATTACHMENT 2Marked-up Technical Specifications Page(Page Provided for After SFP Transition)

Revisedinsert pagerelated to3.7.17-2(Figure3.7.17-1)

SAfter SFP transition Spent Fuel Assembly Storage3.7.17Figure 3.7.17-1Allowable Storage ArraysArray A Two Region 1 assemblies (1) checkerboarded With two blocked cells (X). The Region ........1 assemblies are each in a cell with a stainless steel L-insert.

No NETCO-SNAP-INa insertsare credited.

X Array B Two Region 1 assemblies (1) checkerboarded with two cells containing trash cans (TC). The Region 1 assemblies are each in a cell with a stainless steel L-insert.

Every ': cell without a stainless steel L-insert must contain a NETCO-SNAP-1N insert. TC

.Array Two Region 2 assemblies (2) checkerboarded with one Region 3 assembly (3) and i:,.i;i[i" one blocked cell (X). The Region 2 assemblies are each in a cell with a stainless steel L-insert.

The Region 3 assembly is in a cell containing a

insert. 3 2::OeRegion 2assembly (2) checkerboarded with three Region 4 assemblies (4). T heRegion 2 assembly and the diagonally located Region 4 assembly are each in a storage cell with a stainless steel L-insert.

The two storage cells without a stainless 4

steel L-insert contain a NETCO-SNAP-IN insert.Array E Four Region 5 assemblies (5). Two storage cells contain a stainless steel L-insert.

Onecell contains a

insert. One storage cell contains no insert. "

.,.Four Region 6 assemblies (6). Two storage cells contain a stainless steel L-insert.

The... .-.,other two cells contain no inserts.

Nolte..s:l. The shaded locations indicate cells which contain a stainless steel L-insert.

2. A blocked cell (X) contains a blocking device and only water in the active fuel region.3. NETCO-SNAP-IN inserts must be oriented in the same direction as the stainless steel L-inserts.

4.

inserts are ~only located in cells without a stainless steel L-insert.

5. Any cell containing a fuel assembly or a TC may instead be an empty (water-filled) cell in allstorage arrays.6. Any storage array location designated for a fuel assembly may be replaced with non-fissile material.

Enclosure Supplemental Information Regarding License Amendment Request to Revise Technical Specifications to Incorporate Updated Criticality Safety AnalysisATTACHMENT 3Revised Technical Specifications Page (Clean Copy)(Page Provided for After SFP Transition) 3.7.17-7 After SFP transition Spent Fuel Assembly Storage3.7.17Figure 3.7.17-1A11lowabl e Storaae ArraysArra A 1 XTwo Region 1 assemblies (1) checkerboarded with two blocked cells (X). :i.i7The Region 1 assemblies are each in a cell with a stainless steel X *:7 !L-insert.

No NETCO-SNAP-IN inserts are credited.

Array B ..... TWO Region 1 assemblies (1) checkerboarded with two cells containing trash cans (TC). The Region 1 assemblies are each in a cell with a -

stainless steel L-insert.

Every cell without a stainless steel L- TC insert must contain a NETCO-SNAP-IN insert. Two Region 2 assemblies (2) checkerboarded with one Region 3 assembly(3) and one blocked cell (X). The Region 2 assemblies are each in a cell with a stainless steel L-insert.

The Region 3 assembly is in a 3 cell containing a NETCO-SNAP-IN insert.Array D '< One Region 2 assembly (2) checkerboarded with three Region 4 4assemblies (4). The Region 2 assembly and the diagonally locatedRegion 4 assembly are each in a storage cell with a stainless steel L- insert. The two storage cells without a stainless steel L-insert 4

contain a NETCO-SNAP-IN insert.Array E 5Four Region 5 assemblies (5). Two storage cells contain a stainless 1'!LM:steel L-insert.

One cell contains a NETCO-SNAP-IN insert. One storage cell contains no insert.

Array F 6Four Region 6 assemblies (6). Two storage cells contain a stainless steel L-insert.

The other two cells contain no inserts.

6 Notes:1. The shaded locations indicate cells which contain a stainless steel L-insert*

2. A blocked cell (X) contains a blocking device and only water in the active fuel region.3. NETCO-SNAP-IN inserts must be oriented in the same direction as the stainless steel L-inserts.

4. NETCO-SNAP-IN inserts are only located in cells without a stainless steel L-insert.

5. Any cell containing a fuel assembly or a TC may instead be an empty (water-filled) cell in all storagearrays.6. Any storage array location designated for a fuel assembly may be replaced with non-fissile material.

7. Interface requirements:

Each cell is part of up to four 2x2 arrays and each cell must simultaneously meet the requirements of all those arrays of which it is a part,PALO VERDE UNITS 1,2,3 371- MNMN O3.7.17-7AMENDMENT NO.