RS-13-134, Plant-Specific Path and Schedule for Resolution of Generic Letter 2004-02

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Plant-Specific Path and Schedule for Resolution of Generic Letter 2004-02
ML13135A069
Person / Time
Site: Byron, Braidwood  Constellation icon.png
Issue date: 05/14/2013
From: Gullott D
Exelon Generation Co
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
GL-04-002, RS-13-134
Download: ML13135A069 (7)
v • d • e


Text

1 4300 4300 Winfield Winfield Road Road Warrenville, Warrenville.ILIL60555 60555 Exelon Generation Generation, 630 630 657 6572000 2000 Office Office RS-13-134 RS-13-134 10 10 CFR CFR 50.54(f) 50.54(f)

May 14, May 14, 2013 2013 U. S. Nuclear Regulatory U. Regulatory Commission ATTN:

A Document Control TIN: Document Control Desk Washington,DC Washington, DC 20555-0001 Braidwood Station, Braidwood Station, Units Units 11 and and 2 FacilityOperating Facility Operating License License Nos.Nos. NPF-72 NPF -72 and and NPF-77 NRC Docket Nos.

NRC Nos. STN STN 50-456 and STN STN 50-457 Byron Station, Byron Station, Units 1 and 2 Facility Operating Facility Operating License Nos. NPF-37 and NPF-66 NPF-66 NRC Docket Nos. STN 50-454 and STN NRC STN 50-455 50-455

Subject:

Plant-Specific Path and Schedule for for Resolution Resolution of of Generic Generic LetterLetter2004-02 2004-02

References:

(1) Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Recirculation During Design Basis Accidents at Pressurized Pressurized-Water Reactors, II

-Water Reactors,"

dated September 13, 13, 2004 2004 (2) SECY-12-0093: R. W. Borchardt,Borchardt, U.S.

U.S. Nuclear Nuclear Regulatory Regulatory Commission, Commission,to to The Commissioners, U.S. Nuclear Regulatory Commission, 'Closure "Closure Options Options for Generic Generic' Safety Issue - 191, 191, Assessment of Debris Debris Accumulation on Pressurized-Water Reactor Reactor Sump Sump Performance,"

Performance'" dated dated July July9, 9, 2012 2012 (3) Letter from W. H. Ruland (NRC) (NRC) to to J.

J. C.

C. Butler Butler (NEI),

(NEI), "Nuclear "Nuclear Regulatory Regulatory Commission ReviewReview of of Generic Generic Safety SafetyIssue-191 Issue-191 Nuclear NuclearEnergy EnergyInstitute Institute Revised Schedule for Licensee Submittal of Resolution Path,' Path," dated dated November 21, 21 , 2012 2012 (4) Letter from S. Bahadur Bahadur (NRC)

(NRC) to to W.

W. A.A. Nowinowski Nowinowski (PWR (PWROwners OwnersGroup),

Group),

"Final Safety Safety Evaluation Evaluation forfor Pressurized Pressurized Water WaterReactor ReactorOwners OwnersGroup Group Topical Topical Report Report WCAP-1 6793-NP, Revision 2, 'Evaluation WCAP-16793-NP, 'Evaluation of Long-Term Long-Term Cooling Cooling Considering Considering Particulate Particulate Fibrous Fibrousand andChemical ChemicalDebris Debrisininthe the Recirculating Recirculating Fluid,"'

Fluid,'" dated April April 8, 8, 2013 2013 Generic Generic Safety Safety Issue Issue(GSI)-191, (GSI)-191, "Assessment "AssessmentofofDebrisDebrisAccumulation Accumulation on on Pressurized-Water Pressurized-Water Reactor Reactor (PWR)

(PWR) Sump Performance,"

Performance," remains aa long-standing long-standing open open issue.

issue.GSI-191 GSI-191concluded concluded that that debris debris could could clog clog the the containment containment sump sump strainers strainers in in pressurized pressurizedwater waterreactors reactors(PWRs),

(PWRs),

leading leading to to the the loss lossof of net netpositive positive suction suction head headfor forthe theemergency emergencycore corecooling coolingsystem system(ECCS)

(ECCS) and and containment spray system (CSS) pumps. The Nuclear Regulatory Commission (NRC) issued containment spray system (CSS) pumps. The Nuclear Regulatory Commission (NRC) issued Generic Generic Letter Letter (GL)

(GL) 2004-02, "Potential "Potential Impact Impact of Debris Blockage on Emergency EmergencyRecirculation Recirculation During During Design Basis Accidents at Pressurized-Water Pressurized-Water Reactors,"

Reactors, dated II dated September September13, 13,2004, 2004, (Reference (Reference 1) 1) requesting requesting that that licensees licenseesaddress addressthe theissues issuesraised raisedbybyGSI-1 GSI-191. 91. GL GL2004-02 2004-02was was focused focused onondemonstrating demonstratingcompliance compliancewith with1010CFR CFR50.46.

50.46.

May 14, May 14, 2013 2013 U. S.

U. S. Nuclear N.uclear Regulatory Regulatory Commission Commission Page 22 Page Since thethe issuance issuanceof ofGL GL 2004-02, 2004-02, the theindustry, industry, through through extensive extensive testing testing hashasmade madesignificant significant strides strides inin understanding understanding the theeffects effectsof of post-LOCA post-LOCA debris generation, debris debris transport, transport, sump sump screen screen effectiveness, effectiveness, and,and,most mostrecently, recently, in-vessel in-vesseleffects effects of of the the debris debris that that bypasses bypassesthe thesump sump screens.

screens. LargeLargescope scopemodifications modificationshave havebeen beenimplemented implementedto toincrease increasethe thesurface surfacearea areaofofthe the sump strainers strainers and and reduce reduce thethedebris debrisquantities quantities that that reach reach the the sump sump strainers.

strainers.

On July 9, 2012,2012, the NRC staff issued the NRC issued SECY-12-0093, SECY-12-0093, "Closure "Closure Options Options for for Generic Generic Safety Safety Issue Issue -- 191, 191, Assessment AssessmentofofDebrisDebrisAccumulation Accumulation on on Pressurized-Water Pressurized-WaterReactor ReactorSumpSump Performance," (Reference 2). SECY-12-0093 SECY-12-0093 presentspresentsthreethreeoptions optionsto to the theCommission; Commission; each each considered considered aaviableviablepath pathfor forresolving resolvingGSI-1 91.

GSI-191.

options are:

The options are:

  • Option 1:1: Compliance with 10 CFR with 10 CFR 50.46 50.46 based based on on approved approved models; models;
  • Option 2:2: Mitigative measures and Mitigative measures and alternate methods approach; and and
  • Option 3:3: Different regulatory treatment Different regulatory treatment forfor suction strainer and and in-vessel in-vesseleffects.

effects.

Although Although aa licensee may choose choose to to pursue pursueanyanyoption optionto toachieve achieveclosure, closure,specific specificoptions optionsmaymay lend themselves themselves optimally optimally toto a plant's fiber status.

planfs fiber status. Based Basedon onthethelow lowfiber fiber status, status,Braidwood Braidwood Station, Units 1 and 2; and Byron Station, Units Byron Station, Units 1 and 2, have chosen chosen Option Option 1. 1.

In a letter from W.

In W. H.H. Ruland (NRC) to J. C. C. Butler Butler (NEI),

(NEI), "Nuclear Regulatory Commission Commission Review of Review of Generic Generic Safety Issue-191 Nuclear Nuclear Energy Energy Institute Institute Revised Revised Schedule Schedulefor forLicensee Licensee Submittal Submittal of of Resolution Resolution Path, Path,"II dated dated November 21 21,, 2012 (Reference 3), the NRC NRC extended extended the the date for the GSI-1 GSI-191 91submittal.

submittal. The The revised schedule schedule permits permits the the licensee licenseeto tosubmit submit their their chosen chosen resolution option resolution option and and associated associated resolution resolution implementation implementation schedule schedule to to the the NRC, NRC, 30 30 days days following the following the NRC NRC making making the final final safety evaluation evaluation associated associatedwith withthethereview reviewofofWCAP-1 6793, WCAP-16793, Revision 2, "Evaluation of of Long-Term Long-Term Cooling Cooling Considering Considering Particulate, Particulate, Fibrous and and Chemical Chemical Debris in Debris in the the Recirculating Fluid,"

Recirculating Fluid, (Reference 4),

II (Reference 4), and and the Staff Requirements Memorandum Memorandum associated with associated with SECY-12-0093, IIClosure"Closure Options Options forfor Generic Generic Safety Safety Issue Issue -- 191, Assessment Assessment of of Debris Accumulation on Pressurized-Water Debris Accumulation on Pressurized-Water Reactor Sump Performance,", publicly Performance"', publicly available. available. The final safety final safety evaluation evaluation was made made publicly publicly available April 16,2013; April 16, 2013; therefore, therefore, the the due date date for for this submittal is May 16, 2013.

Attachment 1 to this letter provides the the Braidwood Braidwood Station Station and andByron Byron Station Stationplant-specific plant-specificpath path and schedule schedule for for resolution resolution ofof GSI-1 GSI-191. 91. Attachment 2 provides aa summary summaryof of the the regulatory regulatory commitments made in in this submittal.

questions or you have any questions If you or require require additional information,please additional information, please contact Joseph Joseph A. A. Bauer at (630) 657-2804.

(630)

May 14, 2013 U. S. Nuclear Regulatory Commission Commission Page 3 II declare declare under penalty of of perjury perjury that that the the foregoing foregoing isistrue true and and correct.

correct. Executed Executed on on the the14th 14th day of May 2013.

Respectfully, M. Gullott David M. Gullott Manager Manager -- Licensing Licensing Exelon Generation Company, LLC Attachments:

Attachments: 1.1.Braidwood BraidwoodStation Stationand andByron ByronStation, Station,Plant-Specific Plant-SpecificPath Pathand andSchedule Scheduleforfor Resolution of Generic Letter Letter 2004-02 2004-02

2. Summary of Regulatory Commitments cc: USNRC Region III, Regional Administrator USNRC Senior Resident Inspector, USNRC Inspector, Braidwood Braidwood Station USNRC Senior Resident Inspector, USNRC Inspector, Byron Byron Station

ATTACHMENT11 ATTACHMENT Braidwood Station and Byron Station Plant-Specific Path Plant-Specific Path and Schedule Schedulefor for Resolution Resolutionof ofGeneric GenericLetter Letter 2004-02 2004-02 Introduction Exelon Generation Company (EGC)

Exelon (EGC) has has selected selectedOptionOption11fromfrom Reference Reference22for forBraidwood Braidwood Station, Units Station, Units 11 andand 2, 2, and Byron Station, Units Byron Station, Units11and and 2.2. It has been been determined determined thesetheseunits units meet thethe requirements requirements of of 10 10CFR CFR50.46, 50.46,"Acceptance "Acceptancecriteriacriteriafor for emergency emergencycore corecooling cooling systems for systems for light-water nuclear power light-water nuclear power reactors, reactors,"II based on on approved approved models modelsfor for analyses, analyses, strainer head loss loss testing, testing, and and in-vessel in-vessel effects.

effects.

Current Resolution Status As of MayMay 2013, 2013, Braidwood Braidwood and Byron Byron Stations Stations havehavecompleted completedthe thefollowing following Generic Generic Letter 2004-02 Letter 2004-02 (Reference 1) actions, analyses analyses and andmodifications:

modifications:

  • walkdowns and Latent debris walkdowns and analysis
  • Debris Debris generation analysis
  • Debris transport analysis
  • Positive Suction Head (NPSH)

Net Positive (NPSH) analysis for for CS andand Residual ResidualHeatHeatRemoval Removal(RH) (RH) pumps (taking (taking suction from from the containment containment recirculation recirculation sump) sump)

  • Head loss testing for containment recirculation recirculation sump sump strainers
  • Bypass testing for for containment containment recirculation recirculation sump strainers strainers
  • Wear and blockage blockage analysis analysis forfor components components downstream downstreamof ofcontainment containmentrecirculation recirculation sump strainer
  • Chemical effects testing (bench top and head head loss loss testing) testing)
  • Wear and blockage testing for ECCS ECCS throttle valves
  • Debris blockage testing for CS pump cyclone separator
  • Installation of Installation oftrash trash rack rack upstream upstream of containment recirculation recirculation sump strainers strainers
  • Structural Structural analysis of containment recirculation sump strainers recirculation sump strainers and trash rack rack
  • Removal of fiber insulation in in the the zone-of-influence zone-of-influenceatatBraidwood BraidwoodUnit Unit11and andByron ByronUnitUnit1 1 (Note that Braidwood Unit 2 and Byron Byron UnitUnit 2 have have nonofiber fiber insulation) insulation)
  • Installation of Installation of newnew containment containment recirculation sump strainers strainersat atBraidwood Braidwood Units Units 11and and22 and Byron Byron Units 1 and 2
  • Installation of of new ECCS throttle throttle valves valves Braidwood Braidwood UnitsUnits 11and and22and andByron ByronUnits Units1 1 and 2 Documentation of the resolution resolution for GL 2004-02 for Braidwood Station for Braidwood Station and Byron Station has has been provided provided to to the NRCNRC in in References References 33 through through 8. As AsofofMay May 2013, 2013,EGC EGChas hasno noexisting existing open regulatory regulatory commitments for Braidwood Braidwood StationStation and Byron Station related Byron Station related toto the above documentation. The only remaining remainingopen open issue issue is related related toto in-vessel downstream downstream effects (see (see new regulatory regulatory commitment commitment in in Attachment Attachment 2). 2).

In order to In to address address in-vessel in-vessel downstream downstreameffects, effects,Braidwood BraidwoodStation Stationand andByron ByronStation Stationplanplantoto use the use the criteria criteria ofof 15 15 grams/fuel grams/fuel assembly assemblyestablished establishedbybyWCAP-1 6793-NP Revision WCAP-16793-NP Revision2,2, "Evaluation of IIEvaluation of Long-Term Long-TermCooling CoolingConsidering Considering Particulate, Particulate, Fibrous and Chemical Debris Debris inin the the Recirculating Fluid, Recirculating Fluid,"including II includingany anylimitations limitationsand andconditions conditionsassociated associated with the use use of of the the WCAP based WCAP based on the associated associated NRC NRC Safety Safety Evaluation Evaluation (SE)(SE) (Reference 10). From From the the debris debris Page 11 of Page of 3

ATTACHMENT 11 ATTACHMENT Braidwood Station and Byron Byron Station Station Plant-Specific Path and Schedule Schedulefor for Resolution ResolutionofofGeneric GenericLetterLeHer2004-02 2004-02 generation and and debris debris transport transport analysis, analysis, Braidwood Braidwood StationStation and and Byron Byron Station Station have have determined determined that 22.5 IbmIbm of of fibrous fibrous debris debris can can be be transported to the strainers. As AsBraidwood Braidwood Station Station and and Byron Station have no Byron no fibrous fibrous material material installed installed inin the the zone-of-influence, zone-of-influence, the thefibrous fibrous debris debrisisis completely from from latent latent debris debris quantity quantity inside containment. The Thefibrous fibrous debris debrisquantity quantityisis documented in Reference 6 (see "EGC "EGC response to Issue Issue 3f6,"

3f6," on page 39 of 102). 102). Based Basedon on previously performed previously performed strainer bypass bypass testing, testing, the thetotal total quantity quantity of of fiber fiber conservatively assumedassumed to bypass bypass the the strainer strainerisis5% 50/0(i.e.,

(Le., 1.125 1.125Ibm).

Ibm). Of Ofthis this quantity, quantity, 100%

100% is is conservatively conservatively assumed assumed to reach thethe reactor reactor fuel.

fuel. Considering Considering 193 193 fuel assemblies assemblies in in the the Braidwood Braidwood Station Station andand Byron Byron Station reactor cores, this equates equates to to an an approximate approximate loadingloading of of 2.6 grams/fuel assembly.

The required actionsactions for for the resolution resolution planplan include include documenting documenting the the quantity quantity of of fibrous fibrous debris debris that reaches reaches the thesump sumpstrainers strainersand anddocumenting documentingcompliance compliancewith withthe thelimitations limitations and andconditions conditions of the NRCNRC SE SE forfor WCAP-1 WCAP-16793-NP6793-NP Revision 2. 2.

Licensing Basis Commitments EGC does EGC does not have open open commitments commitments within within the Braidwood Braidwood Station and Byron Byron Station Station commitment management management system systemtotoprovide provideadditional additionalupdates updatesororinformation information to to the the NRC NRC regarding GL 2004-02.

Resolution Schedule EGC does not have any EGC any open open issues related to the resolutionresolution of of GSI-1 GSI-191 91 except for in-vessel downstream effects.effects. EGC EGCwill will complete complete resolution resolution of of the the in-vessel in-vesseldownstream downstreameffects effectsfor forall all Braidwood Station and Byron four Braidwood Byron Station unitsunits within within twotwo refueling refueling outages outages after after January January1,1, 2013, for the final final Braidwood and and Byron Byron unit; unit; i.e.,

Le., upon upon startup startupofofBraidwood BraidwoodStation, Station,Unit Unit2,2, Cycle 19 in in the fall of 2015.

fall of 2015. At time, no physical modifications At this time, modifications are are anticipated to be required required for any of for of the the four four units.

units. TheThe final final resolution will be documented will be documented in a submittal to the NRC. NRC. ThisThis submittal will also include will also include documentation documentation of compliance with the limitations limitations and and conditions of the NRC SE for NRC WCAP-16793-NP Revision 2.

forWCAP-16793-NP If the If the NRC NRC hashas follow-up questions regarding this submittal, follow-up questions submittal, EGCEGC will hold discussions will hold discussions withwith the NRC in NRC in order order to establish aa mutuallymutually acceptable acceptabletimeline timelinefor for resolution.

resolution.

References

1. Generic Letter 2004-02, "Potential IIPotential Impact Impact of of Debris Blockage on on Emergency EmergencyRecirculation Recirculation During Design During Design Basis Basis Accidents Accidents at at Pressurized-Water Pressurized-Water Reactors,Reactors,"II dated September September13, 13,2004 2004
2. NRCNRC Document SECY-12-0093, SECY-12-0093, "Closure Options for Generic Safety Safety Issue Issue--191,191, Assessment of Assessment of Debris Debris Accumulation Accumulation on on Pressurized-Water Reactor Sump Sump Performance,"

Performance,"

dated July 9, 2012 Letter from

3. Letter from K. K. R.

R.Jury Jury (Exelon (Exelon Generation Generation Company, LLC LLC and and AmerGen AmerGen Energy Company, LLC)totou.

LLC) U.S. S. Nuclear Nuclear Regulatory Regulatory Commission, Commission, "Exelon/AmerGen "Exelon/AmerGen Response Response to to NRC NRC Generic Letter 2004-02, 'Potential Impact of IPotentiallmpact of Debris Debris Blockage Blockage on on Emergency EmergencyRecirculation Recirculation During Design Basis Accidents During Accidents at Pressurized-Water Reactors,"' Reactors, III dated dated March March 7, 7, 2005 2005 Page 2 of 3

ATTACHMENT ATTACHMENT 11 Braidwood Station and Byron Byron Station Plant-Specific PathPath and Schedule Schedulefor forResolution ResolutionofofGeneric GenericLetter Letter2004-02 2004-02 Letter from

4. Letter from P. P. B.

B. Cowan Company, LLC Cowan (Exelon Generation Company, LLC and AmerGen EnergyEnergy Company, LLC) to U. u. S. Nuclear Nuclear Regulatory Regulatory Commission, Commission,"Exelon/ AmerGen Response IIExelon/AmerGen Response to to NRC Generic Letter 2004-02, 'Potential Letter 2004-02, 'Potential Impact of of Debris Debris Blockage on Emergency Emergency Recirculation During Recirculation DuringDesign Design Basis Accidents Accidents atat Pressurized -Water Reactors,"'

Pressurized-Water Reactors, III dated dated September 1, 2005

5. Letter from K. R. Jury (Exelon Generation Company, Company, LLC)LLC) to u. S.

to U. S. Nuclear Nuclear Regulatory Regulatory Commission, "Supplement to Exelon Exelon Response Response to to NRC NRC Generic Generic Letter Letter2004-02, 2004-02, 'Potential

'Potential Impact of Debris Blockage on Emergency Recirculation Recirculation During During Design Design Basis Basis Accidents Accidents atat Pressurized-Water Reactors,"'

Reactors,1I1 dated May 31, 2006 31,2006

6. Letter from from Patrick Patrick R.

R. Simpson Simpson (Exelon Generation Generation Company, Company,LLC), LLC), "Supplemental "Supplemental

Response

Responseto toNRC NRC Generic GenericLetter Letter2004-02, 2004-02,'Potential Impact of IPotentiallmpact ofDebris Debris Blockage Blockageon on Emergency Recirculation DuringDesign Recirculation During Design Basis Basis Accidents Accidents at at Pressurized-Water Pressurized-Water Reactors,'"

Reactors,'"

dated December 31, 2007 31,2007 from Patrick

7. Letter from Patrick R.

R. Simpson Simpson (Exelon (Exelon Generation Generation Company, LLC), "Response to Request LLC), IIResponse Request for Additional Additional Information InformationRelated Related to to NRC NRC Generic Letter 2004-02, 2004-02, 'Potential IPotentiallmpact Impact of of Debris Blockage on Emergency Recirculation During Design Recirculation During Design Basis Accidents at Pressurized Pressurized Water Reactors,'"

Reactors,"' dated dated September 19, 2008 Letter from

8. Letter from Patrick Patrick R.

R. Simpson Simpson (Exelon (Exelon Generation Generation Company, LLC), "Response to Request LLC), IIResponse Request for Additional Additional Information InformationRelated Related to to NRC NRC Generic Letter 2004-02, 'Potential IPotentiallmpact Impact of of Emergency Recirculation Debris Blockage on Emergency Recirculation During During Design Accidents at Pressurized Design Basis Accidents Water Reactors,"'

Reactors,'" dated MayMay 29, 2009

9. Letter from from W.W. H.H. Ruland (NRC) to J. C. C. Butler Butler (NEI),

(NEI), "Nuclear IINuclear Regulatory Regulatory Commission Commission Review of Review of Generic Generic Safety Safety Issue-191 Nuclear Nuclear Energy Energy Institute Institute Revised Revised Schedule Schedulefor for Licensee Submittal of Resolution Path,1I of Resolution dated November Path," dated November 21, 21,2012 2012

10. Letter from from S. S. Bahadur (NRC) to W. A.

Bahadur (NRC) A. Nowinowski Nowinowski (PWR (PWR Owners "Final Safety Owners Group), "Final Evaluation for Evaluation for Pressurized Pressurized Water Water Reactor ReactorOwners OwnersGroup GroupTopical TopicalReport WCAP-1 6793-NP, ReportWCAP-16793-NP, Revision 2, 'Evaluation of Long-Term Revision Long-Term Cooling Cooling Considering Considering Particulate Fibrous and and Chemical Chemical Debris inin the Recirculating Fluid,"'

Fluid,1II dated April 8, 2013 April 8, Page33of3 Page of 3

ATTACHMENT 2 Braidwood Station and Byron Station Plant-Specific Path and Schedule for Resolution Resolution ofof Generic Generic Letter Letter 2004-02 2004-02 Summary of Regulatory Commitments The following following table table identifies identifies those committed to those actions committed to by by Exelon Exelon Generation GenerationCompany, Company,LLCLLC (EGC) in (EGC) in this this document.

document. Any Any other other statements statementsininthis thissubmittal submittalare areprovided providedfor forinformation information purposes and purposes and are arenot notconsidered consideredto tobeberegulatory regulatorycommitments.

commitments.

COMMITTED DATE DATE COMMITMENT COMMITMENT TYPE OR "OUTAGE" "OUTAGE" ONE-TIME PROGRAMMATIC ACTION (Yes/No)

(Yes/No)

EGC will submit a letterletter addressing addressing the final resolution resolution of of GSI-1 91 in-GSI-191 in-vessel downstream effects for all all Upon Startup of Braidwood Braidwood Station and and Byron Byron Braidwood Station, Yes No Station units; and will document will document Unit Unit 2, 19 2, Cycle 19 compliance with compliance with the the limitations limitations and and (Fall 2015)

(Fall conditions of the NRC SE for WCAP-16793-NP, Revision Revision 2.

Page 11 of of 11

Text

1 4300 4300 Winfield Winfield Road Road Warrenville, Warrenville.ILIL60555 60555 Exelon Generation Generation, 630 630 657 6572000 2000 Office Office RS-13-134 RS-13-134 10 10 CFR CFR 50.54(f) 50.54(f)

May 14, May 14, 2013 2013 U. S. Nuclear Regulatory U. Regulatory Commission ATTN:

A Document Control TIN: Document Control Desk Washington,DC Washington, DC 20555-0001 Braidwood Station, Braidwood Station, Units Units 11 and and 2 FacilityOperating Facility Operating License License Nos.Nos. NPF-72 NPF -72 and and NPF-77 NRC Docket Nos.

NRC Nos. STN STN 50-456 and STN STN 50-457 Byron Station, Byron Station, Units 1 and 2 Facility Operating Facility Operating License Nos. NPF-37 and NPF-66 NPF-66 NRC Docket Nos. STN 50-454 and STN NRC STN 50-455 50-455

Subject:

Plant-Specific Path and Schedule for for Resolution Resolution of of Generic Generic LetterLetter2004-02 2004-02

References:

(1) Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Recirculation During Design Basis Accidents at Pressurized Pressurized-Water Reactors, II

-Water Reactors,"

dated September 13, 13, 2004 2004 (2) SECY-12-0093: R. W. Borchardt,Borchardt, U.S.

U.S. Nuclear Nuclear Regulatory Regulatory Commission, Commission,to to The Commissioners, U.S. Nuclear Regulatory Commission, 'Closure "Closure Options Options for Generic Generic' Safety Issue - 191, 191, Assessment of Debris Debris Accumulation on Pressurized-Water Reactor Reactor Sump Sump Performance,"

Performance'" dated dated July July9, 9, 2012 2012 (3) Letter from W. H. Ruland (NRC) (NRC) to to J.

J. C.

C. Butler Butler (NEI),

(NEI), "Nuclear "Nuclear Regulatory Regulatory Commission ReviewReview of of Generic Generic Safety SafetyIssue-191 Issue-191 Nuclear NuclearEnergy EnergyInstitute Institute Revised Schedule for Licensee Submittal of Resolution Path,' Path," dated dated November 21, 21 , 2012 2012 (4) Letter from S. Bahadur Bahadur (NRC)

(NRC) to to W.

W. A.A. Nowinowski Nowinowski (PWR (PWROwners OwnersGroup),

Group),

"Final Safety Safety Evaluation Evaluation forfor Pressurized Pressurized Water WaterReactor ReactorOwners OwnersGroup Group Topical Topical Report Report WCAP-1 6793-NP, Revision 2, 'Evaluation WCAP-16793-NP, 'Evaluation of Long-Term Long-Term Cooling Cooling Considering Considering Particulate Particulate Fibrous Fibrousand andChemical ChemicalDebris Debrisininthe the Recirculating Recirculating Fluid,"'

Fluid,'" dated April April 8, 8, 2013 2013 Generic Generic Safety Safety Issue Issue(GSI)-191, (GSI)-191, "Assessment "AssessmentofofDebrisDebrisAccumulation Accumulation on on Pressurized-Water Pressurized-Water Reactor Reactor (PWR)

(PWR) Sump Performance,"

Performance," remains aa long-standing long-standing open open issue.

issue.GSI-191 GSI-191concluded concluded that that debris debris could could clog clog the the containment containment sump sump strainers strainers in in pressurized pressurizedwater waterreactors reactors(PWRs),

(PWRs),

leading leading to to the the loss lossof of net netpositive positive suction suction head headfor forthe theemergency emergencycore corecooling coolingsystem system(ECCS)

(ECCS) and and containment spray system (CSS) pumps. The Nuclear Regulatory Commission (NRC) issued containment spray system (CSS) pumps. The Nuclear Regulatory Commission (NRC) issued Generic Generic Letter Letter (GL)

(GL) 2004-02, "Potential "Potential Impact Impact of Debris Blockage on Emergency EmergencyRecirculation Recirculation During During Design Basis Accidents at Pressurized-Water Pressurized-Water Reactors,"

Reactors, dated II dated September September13, 13,2004, 2004, (Reference (Reference 1) 1) requesting requesting that that licensees licenseesaddress addressthe theissues issuesraised raisedbybyGSI-1 GSI-191. 91. GL GL2004-02 2004-02was was focused focused onondemonstrating demonstratingcompliance compliancewith with1010CFR CFR50.46.

50.46.

May 14, May 14, 2013 2013 U. S.

U. S. Nuclear N.uclear Regulatory Regulatory Commission Commission Page 22 Page Since thethe issuance issuanceof ofGL GL 2004-02, 2004-02, the theindustry, industry, through through extensive extensive testing testing hashasmade madesignificant significant strides strides inin understanding understanding the theeffects effectsof of post-LOCA post-LOCA debris generation, debris debris transport, transport, sump sump screen screen effectiveness, effectiveness, and,and,most mostrecently, recently, in-vessel in-vesseleffects effects of of the the debris debris that that bypasses bypassesthe thesump sump screens.

screens. LargeLargescope scopemodifications modificationshave havebeen beenimplemented implementedto toincrease increasethe thesurface surfacearea areaofofthe the sump strainers strainers and and reduce reduce thethedebris debrisquantities quantities that that reach reach the the sump sump strainers.

strainers.

On July 9, 2012,2012, the NRC staff issued the NRC issued SECY-12-0093, SECY-12-0093, "Closure "Closure Options Options for for Generic Generic Safety Safety Issue Issue -- 191, 191, Assessment AssessmentofofDebrisDebrisAccumulation Accumulation on on Pressurized-Water Pressurized-WaterReactor ReactorSumpSump Performance," (Reference 2). SECY-12-0093 SECY-12-0093 presentspresentsthreethreeoptions optionsto to the theCommission; Commission; each each considered considered aaviableviablepath pathfor forresolving resolvingGSI-1 91.

GSI-191.

options are:

The options are:

  • Option 1:1: Compliance with 10 CFR with 10 CFR 50.46 50.46 based based on on approved approved models; models;
  • Option 2:2: Mitigative measures and Mitigative measures and alternate methods approach; and and
  • Option 3:3: Different regulatory treatment Different regulatory treatment forfor suction strainer and and in-vessel in-vesseleffects.

effects.

Although Although aa licensee may choose choose to to pursue pursueanyanyoption optionto toachieve achieveclosure, closure,specific specificoptions optionsmaymay lend themselves themselves optimally optimally toto a plant's fiber status.

planfs fiber status. Based Basedon onthethelow lowfiber fiber status, status,Braidwood Braidwood Station, Units 1 and 2; and Byron Station, Units Byron Station, Units 1 and 2, have chosen chosen Option Option 1. 1.

In a letter from W.

In W. H.H. Ruland (NRC) to J. C. C. Butler Butler (NEI),

(NEI), "Nuclear Regulatory Commission Commission Review of Review of Generic Generic Safety Issue-191 Nuclear Nuclear Energy Energy Institute Institute Revised Revised Schedule Schedulefor forLicensee Licensee Submittal Submittal of of Resolution Resolution Path, Path,"II dated dated November 21 21,, 2012 (Reference 3), the NRC NRC extended extended the the date for the GSI-1 GSI-191 91submittal.

submittal. The The revised schedule schedule permits permits the the licensee licenseeto tosubmit submit their their chosen chosen resolution option resolution option and and associated associated resolution resolution implementation implementation schedule schedule to to the the NRC, NRC, 30 30 days days following the following the NRC NRC making making the final final safety evaluation evaluation associated associatedwith withthethereview reviewofofWCAP-1 6793, WCAP-16793, Revision 2, "Evaluation of of Long-Term Long-Term Cooling Cooling Considering Considering Particulate, Particulate, Fibrous and and Chemical Chemical Debris in Debris in the the Recirculating Fluid,"

Recirculating Fluid, (Reference 4),

II (Reference 4), and and the Staff Requirements Memorandum Memorandum associated with associated with SECY-12-0093, IIClosure"Closure Options Options forfor Generic Generic Safety Safety Issue Issue -- 191, Assessment Assessment of of Debris Accumulation on Pressurized-Water Debris Accumulation on Pressurized-Water Reactor Sump Performance,", publicly Performance"', publicly available. available. The final safety final safety evaluation evaluation was made made publicly publicly available April 16,2013; April 16, 2013; therefore, therefore, the the due date date for for this submittal is May 16, 2013.

Attachment 1 to this letter provides the the Braidwood Braidwood Station Station and andByron Byron Station Stationplant-specific plant-specificpath path and schedule schedule for for resolution resolution ofof GSI-1 GSI-191. 91. Attachment 2 provides aa summary summaryof of the the regulatory regulatory commitments made in in this submittal.

questions or you have any questions If you or require require additional information,please additional information, please contact Joseph Joseph A. A. Bauer at (630) 657-2804.

(630)

May 14, 2013 U. S. Nuclear Regulatory Commission Commission Page 3 II declare declare under penalty of of perjury perjury that that the the foregoing foregoing isistrue true and and correct.

correct. Executed Executed on on the the14th 14th day of May 2013.

Respectfully, M. Gullott David M. Gullott Manager Manager -- Licensing Licensing Exelon Generation Company, LLC Attachments:

Attachments: 1.1.Braidwood BraidwoodStation Stationand andByron ByronStation, Station,Plant-Specific Plant-SpecificPath Pathand andSchedule Scheduleforfor Resolution of Generic Letter Letter 2004-02 2004-02

2. Summary of Regulatory Commitments cc: USNRC Region III, Regional Administrator USNRC Senior Resident Inspector, USNRC Inspector, Braidwood Braidwood Station USNRC Senior Resident Inspector, USNRC Inspector, Byron Byron Station

ATTACHMENT11 ATTACHMENT Braidwood Station and Byron Station Plant-Specific Path Plant-Specific Path and Schedule Schedulefor for Resolution Resolutionof ofGeneric GenericLetter Letter 2004-02 2004-02 Introduction Exelon Generation Company (EGC)

Exelon (EGC) has has selected selectedOptionOption11fromfrom Reference Reference22for forBraidwood Braidwood Station, Units Station, Units 11 andand 2, 2, and Byron Station, Units Byron Station, Units11and and 2.2. It has been been determined determined thesetheseunits units meet thethe requirements requirements of of 10 10CFR CFR50.46, 50.46,"Acceptance "Acceptancecriteriacriteriafor for emergency emergencycore corecooling cooling systems for systems for light-water nuclear power light-water nuclear power reactors, reactors,"II based on on approved approved models modelsfor for analyses, analyses, strainer head loss loss testing, testing, and and in-vessel in-vessel effects.

effects.

Current Resolution Status As of MayMay 2013, 2013, Braidwood Braidwood and Byron Byron Stations Stations havehavecompleted completedthe thefollowing following Generic Generic Letter 2004-02 Letter 2004-02 (Reference 1) actions, analyses analyses and andmodifications:

modifications:

  • walkdowns and Latent debris walkdowns and analysis
  • Debris Debris generation analysis
  • Debris transport analysis
  • Positive Suction Head (NPSH)

Net Positive (NPSH) analysis for for CS andand Residual ResidualHeatHeatRemoval Removal(RH) (RH) pumps (taking (taking suction from from the containment containment recirculation recirculation sump) sump)

  • Head loss testing for containment recirculation recirculation sump sump strainers
  • Bypass testing for for containment containment recirculation recirculation sump strainers strainers
  • Wear and blockage blockage analysis analysis forfor components components downstream downstreamof ofcontainment containmentrecirculation recirculation sump strainer
  • Chemical effects testing (bench top and head head loss loss testing) testing)
  • Wear and blockage testing for ECCS ECCS throttle valves
  • Debris blockage testing for CS pump cyclone separator
  • Installation of Installation oftrash trash rack rack upstream upstream of containment recirculation recirculation sump strainers strainers
  • Structural Structural analysis of containment recirculation sump strainers recirculation sump strainers and trash rack rack
  • Removal of fiber insulation in in the the zone-of-influence zone-of-influenceatatBraidwood BraidwoodUnit Unit11and andByron ByronUnitUnit1 1 (Note that Braidwood Unit 2 and Byron Byron UnitUnit 2 have have nonofiber fiber insulation) insulation)
  • Installation of Installation of newnew containment containment recirculation sump strainers strainersat atBraidwood Braidwood Units Units 11and and22 and Byron Byron Units 1 and 2
  • Installation of of new ECCS throttle throttle valves valves Braidwood Braidwood UnitsUnits 11and and22and andByron ByronUnits Units1 1 and 2 Documentation of the resolution resolution for GL 2004-02 for Braidwood Station for Braidwood Station and Byron Station has has been provided provided to to the NRCNRC in in References References 33 through through 8. As AsofofMay May 2013, 2013,EGC EGChas hasno noexisting existing open regulatory regulatory commitments for Braidwood Braidwood StationStation and Byron Station related Byron Station related toto the above documentation. The only remaining remainingopen open issue issue is related related toto in-vessel downstream downstream effects (see (see new regulatory regulatory commitment commitment in in Attachment Attachment 2). 2).

In order to In to address address in-vessel in-vessel downstream downstreameffects, effects,Braidwood BraidwoodStation Stationand andByron ByronStation Stationplanplantoto use the use the criteria criteria ofof 15 15 grams/fuel grams/fuel assembly assemblyestablished establishedbybyWCAP-1 6793-NP Revision WCAP-16793-NP Revision2,2, "Evaluation of IIEvaluation of Long-Term Long-TermCooling CoolingConsidering Considering Particulate, Particulate, Fibrous and Chemical Debris Debris inin the the Recirculating Fluid, Recirculating Fluid,"including II includingany anylimitations limitationsand andconditions conditionsassociated associated with the use use of of the the WCAP based WCAP based on the associated associated NRC NRC Safety Safety Evaluation Evaluation (SE)(SE) (Reference 10). From From the the debris debris Page 11 of Page of 3

ATTACHMENT 11 ATTACHMENT Braidwood Station and Byron Byron Station Station Plant-Specific Path and Schedule Schedulefor for Resolution ResolutionofofGeneric GenericLetterLeHer2004-02 2004-02 generation and and debris debris transport transport analysis, analysis, Braidwood Braidwood StationStation and and Byron Byron Station Station have have determined determined that 22.5 IbmIbm of of fibrous fibrous debris debris can can be be transported to the strainers. As AsBraidwood Braidwood Station Station and and Byron Station have no Byron no fibrous fibrous material material installed installed inin the the zone-of-influence, zone-of-influence, the thefibrous fibrous debris debrisisis completely from from latent latent debris debris quantity quantity inside containment. The Thefibrous fibrous debris debrisquantity quantityisis documented in Reference 6 (see "EGC "EGC response to Issue Issue 3f6,"

3f6," on page 39 of 102). 102). Based Basedon on previously performed previously performed strainer bypass bypass testing, testing, the thetotal total quantity quantity of of fiber fiber conservatively assumedassumed to bypass bypass the the strainer strainerisis5% 50/0(i.e.,

(Le., 1.125 1.125Ibm).

Ibm). Of Ofthis this quantity, quantity, 100%

100% is is conservatively conservatively assumed assumed to reach thethe reactor reactor fuel.

fuel. Considering Considering 193 193 fuel assemblies assemblies in in the the Braidwood Braidwood Station Station andand Byron Byron Station reactor cores, this equates equates to to an an approximate approximate loadingloading of of 2.6 grams/fuel assembly.

The required actionsactions for for the resolution resolution planplan include include documenting documenting the the quantity quantity of of fibrous fibrous debris debris that reaches reaches the thesump sumpstrainers strainersand anddocumenting documentingcompliance compliancewith withthe thelimitations limitations and andconditions conditions of the NRCNRC SE SE forfor WCAP-1 WCAP-16793-NP6793-NP Revision 2. 2.

Licensing Basis Commitments EGC does EGC does not have open open commitments commitments within within the Braidwood Braidwood Station and Byron Byron Station Station commitment management management system systemtotoprovide provideadditional additionalupdates updatesororinformation information to to the the NRC NRC regarding GL 2004-02.

Resolution Schedule EGC does not have any EGC any open open issues related to the resolutionresolution of of GSI-1 GSI-191 91 except for in-vessel downstream effects.effects. EGC EGCwill will complete complete resolution resolution of of the the in-vessel in-vesseldownstream downstreameffects effectsfor forall all Braidwood Station and Byron four Braidwood Byron Station unitsunits within within twotwo refueling refueling outages outages after after January January1,1, 2013, for the final final Braidwood and and Byron Byron unit; unit; i.e.,

Le., upon upon startup startupofofBraidwood BraidwoodStation, Station,Unit Unit2,2, Cycle 19 in in the fall of 2015.

fall of 2015. At time, no physical modifications At this time, modifications are are anticipated to be required required for any of for of the the four four units.

units. TheThe final final resolution will be documented will be documented in a submittal to the NRC. NRC. ThisThis submittal will also include will also include documentation documentation of compliance with the limitations limitations and and conditions of the NRC SE for NRC WCAP-16793-NP Revision 2.

forWCAP-16793-NP If the If the NRC NRC hashas follow-up questions regarding this submittal, follow-up questions submittal, EGCEGC will hold discussions will hold discussions withwith the NRC in NRC in order order to establish aa mutuallymutually acceptable acceptabletimeline timelinefor for resolution.

resolution.

References

1. Generic Letter 2004-02, "Potential IIPotential Impact Impact of of Debris Blockage on on Emergency EmergencyRecirculation Recirculation During Design During Design Basis Basis Accidents Accidents at at Pressurized-Water Pressurized-Water Reactors,Reactors,"II dated September September13, 13,2004 2004
2. NRCNRC Document SECY-12-0093, SECY-12-0093, "Closure Options for Generic Safety Safety Issue Issue--191,191, Assessment of Assessment of Debris Debris Accumulation Accumulation on on Pressurized-Water Reactor Sump Sump Performance,"

Performance,"

dated July 9, 2012 Letter from

3. Letter from K. K. R.

R.Jury Jury (Exelon (Exelon Generation Generation Company, LLC LLC and and AmerGen AmerGen Energy Company, LLC)totou.

LLC) U.S. S. Nuclear Nuclear Regulatory Regulatory Commission, Commission, "Exelon/AmerGen "Exelon/AmerGen Response Response to to NRC NRC Generic Letter 2004-02, 'Potential Impact of IPotentiallmpact of Debris Debris Blockage Blockage on on Emergency EmergencyRecirculation Recirculation During Design Basis Accidents During Accidents at Pressurized-Water Reactors,"' Reactors, III dated dated March March 7, 7, 2005 2005 Page 2 of 3

ATTACHMENT ATTACHMENT 11 Braidwood Station and Byron Byron Station Plant-Specific PathPath and Schedule Schedulefor forResolution ResolutionofofGeneric GenericLetter Letter2004-02 2004-02 Letter from

4. Letter from P. P. B.

B. Cowan Company, LLC Cowan (Exelon Generation Company, LLC and AmerGen EnergyEnergy Company, LLC) to U. u. S. Nuclear Nuclear Regulatory Regulatory Commission, Commission,"Exelon/ AmerGen Response IIExelon/AmerGen Response to to NRC Generic Letter 2004-02, 'Potential Letter 2004-02, 'Potential Impact of of Debris Debris Blockage on Emergency Emergency Recirculation During Recirculation DuringDesign Design Basis Accidents Accidents atat Pressurized -Water Reactors,"'

Pressurized-Water Reactors, III dated dated September 1, 2005

5. Letter from K. R. Jury (Exelon Generation Company, Company, LLC)LLC) to u. S.

to U. S. Nuclear Nuclear Regulatory Regulatory Commission, "Supplement to Exelon Exelon Response Response to to NRC NRC Generic Generic Letter Letter2004-02, 2004-02, 'Potential

'Potential Impact of Debris Blockage on Emergency Recirculation Recirculation During During Design Design Basis Basis Accidents Accidents atat Pressurized-Water Reactors,"'

Reactors,1I1 dated May 31, 2006 31,2006

6. Letter from from Patrick Patrick R.

R. Simpson Simpson (Exelon Generation Generation Company, Company,LLC), LLC), "Supplemental "Supplemental

Response

Responseto toNRC NRC Generic GenericLetter Letter2004-02, 2004-02,'Potential Impact of IPotentiallmpact ofDebris Debris Blockage Blockageon on Emergency Recirculation DuringDesign Recirculation During Design Basis Basis Accidents Accidents at at Pressurized-Water Pressurized-Water Reactors,'"

Reactors,'"

dated December 31, 2007 31,2007 from Patrick

7. Letter from Patrick R.

R. Simpson Simpson (Exelon (Exelon Generation Generation Company, LLC), "Response to Request LLC), IIResponse Request for Additional Additional Information InformationRelated Related to to NRC NRC Generic Letter 2004-02, 2004-02, 'Potential IPotentiallmpact Impact of of Debris Blockage on Emergency Recirculation During Design Recirculation During Design Basis Accidents at Pressurized Pressurized Water Reactors,'"

Reactors,"' dated dated September 19, 2008 Letter from

8. Letter from Patrick Patrick R.

R. Simpson Simpson (Exelon (Exelon Generation Generation Company, LLC), "Response to Request LLC), IIResponse Request for Additional Additional Information InformationRelated Related to to NRC NRC Generic Letter 2004-02, 'Potential IPotentiallmpact Impact of of Emergency Recirculation Debris Blockage on Emergency Recirculation During During Design Accidents at Pressurized Design Basis Accidents Water Reactors,"'

Reactors,'" dated MayMay 29, 2009

9. Letter from from W.W. H.H. Ruland (NRC) to J. C. C. Butler Butler (NEI),

(NEI), "Nuclear IINuclear Regulatory Regulatory Commission Commission Review of Review of Generic Generic Safety Safety Issue-191 Nuclear Nuclear Energy Energy Institute Institute Revised Revised Schedule Schedulefor for Licensee Submittal of Resolution Path,1I of Resolution dated November Path," dated November 21, 21,2012 2012

10. Letter from from S. S. Bahadur (NRC) to W. A.

Bahadur (NRC) A. Nowinowski Nowinowski (PWR (PWR Owners "Final Safety Owners Group), "Final Evaluation for Evaluation for Pressurized Pressurized Water Water Reactor ReactorOwners OwnersGroup GroupTopical TopicalReport WCAP-1 6793-NP, ReportWCAP-16793-NP, Revision 2, 'Evaluation of Long-Term Revision Long-Term Cooling Cooling Considering Considering Particulate Fibrous and and Chemical Chemical Debris inin the Recirculating Fluid,"'

Fluid,1II dated April 8, 2013 April 8, Page33of3 Page of 3

ATTACHMENT 2 Braidwood Station and Byron Station Plant-Specific Path and Schedule for Resolution Resolution ofof Generic Generic Letter Letter 2004-02 2004-02 Summary of Regulatory Commitments The following following table table identifies identifies those committed to those actions committed to by by Exelon Exelon Generation GenerationCompany, Company,LLCLLC (EGC) in (EGC) in this this document.

document. Any Any other other statements statementsininthis thissubmittal submittalare areprovided providedfor forinformation information purposes and purposes and are arenot notconsidered consideredto tobeberegulatory regulatorycommitments.

commitments.

COMMITTED DATE DATE COMMITMENT COMMITMENT TYPE OR "OUTAGE" "OUTAGE" ONE-TIME PROGRAMMATIC ACTION (Yes/No)

(Yes/No)

EGC will submit a letterletter addressing addressing the final resolution resolution of of GSI-1 91 in-GSI-191 in-vessel downstream effects for all all Upon Startup of Braidwood Braidwood Station and and Byron Byron Braidwood Station, Yes No Station units; and will document will document Unit Unit 2, 19 2, Cycle 19 compliance with compliance with the the limitations limitations and and (Fall 2015)

(Fall conditions of the NRC SE for WCAP-16793-NP, Revision Revision 2.

Page 11 of of 11

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