ML13324A094
| ML13324A094 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood  |
| Issue date: | 11/18/2013 |
| From: | Gullott D Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| RS-1 3-269 | |
| Download: ML13324A094 (9) | |
Text
1 on Generation ti RS-1 3-269 RS-13-269 10 CFR 50.90 November 18, 2013 U. S. Nuclear Nuclear Regulatory Regulatory Commission Commission ATTN: Document Control Desk Desk Washington, DC Washington, DC 20555-0001 20555-0001 Braidwood Station, Units 11 and and 22 Facility Operating License Nos. Nos. NPF-72 NPF-72 and and NPF-77 NPF-77 NRC Docket Nos.
NRC Nos. STN 50-456 and STN 50-457 Byron Station, Units 1 and 2 Byron Facility Operating License Nos. NPF-37 NPF-37 and and NPF-66 NPF-66 NRC Docket Nos. Nos. STN 50-454 and STN 50-455
Subject:
Supplemental Response ResponsetotoNRC NRCHELBHELBAudit Audit Request RequestforforInformation Information Supporting Supporting Request for License Amendment Regarding Measurement Measurement Uncertainty Uncertainty Recapture Recapture Power Uprate
References:
- 1. Letter from from Craig Craig Lambert Lambert (Exelon (Exelon Generation Company,LLC)
Generation Company, LLC) toto U. S. NRC, U. NRC, "Request for for License Amendment Regarding Measurement Uncertainty Recapture Power Power Uprate,"
Uprate," dated dated June 23, 2011 2011
- 2. Letter Letter from from J.J. S. Wiebe (U.(U. S. NRC)
NRC) to M. M. J. Pacilio Pacilio (Exelon (Exelon Generation Company, Company, LLC),
LLC), "Byron "Byron Station, Station, Unit Unit Nos.
Nos. 1 and 2, andand Braidwood Braidwood Station, Units 1 and and 22 -- Request Requestfor forAdditional Additional Information Information and Suspension Suspension of of Review Review of of License Amendment Amendment Request Request forfor Power Power Uprate (TAC (TAC Nos.
Nos. ME6587, ME6588, ME6589, and and ME6590),"
ME6590)," dated dated December 6, 2012 6,2012
- 3. Letter from from David David M.M. Gullott Gullott(Exelon (Exelon Generation Company, LLC)
Generation Company, LLC) to U. S. NRC, "Additional U. InformationSupporting "Additional Information Supporting Request Request for License License Measurement Uncertainty Amendment Regarding Measurement Uncertainty Recapture Recapture Power Power Uprate," dated July 5,2013 Uprate," 5, 2013 E-Mail fromJ.S.Wiebe(U.
- 4. E-Mail from J. S. Wiebe (U. S. S. NRC)
NRC) to toDavid DavidM. M. Gullott Gullott (Exelon (Exelon Generation Company,LLC),
Generation Company, LLC), "Preliminary "Preliminary RAI RAI Regarding Regarding TB TB Bldg Bldg HELB,"
HELB,"dateddated August August 29, 2013
- 5. Letter from
- 5. from David M. M. Gullott (Exelon Generation Company, LLC) LLC) to U. S. NRC, " Supplemental Response to NRC HELB NRC HELB Audit Request Request for Information Supporting Request for License License Amendment Regarding Regarding Measurement Uncertainty Recapture Power Measurement Uncertainty Power Uprate,"
Uprate," dated dated September 5, 5, 2013 2013 In In Reference Exelon Generation Company, LLC Reference 1, Exelon LLC (EGC)
(EGC)requested requested anan amendment amendment to to FacilityOperating Facility Operating License License Nos.
Nos. NPF-72, NPF-77, NPF-37 NPF-37 and and NPF-66 NPF-66for for Braidwood Braidwood Station, Units Units 1 and 2, and and Byron Byron Station, Units Units 1 and 2, 2, respectively.
respectively. Specifically, Specifically, the the
November 18, 18, 2013 U.S. Nuclear Regulatory Commission Page 2 proposed changes changesrevise revisethe theOperating OperatingLicenseLicenseand andTechnical Technical Specifications Specifications to to implement an increase increase in in rated rated thermal thermal power power of of approximately 1.63% based based on on increased feedwater flow measurement accuracy.
flow measurement In Reference In Reference 2, 2, the the NRC NRC requested requestedadditional additionalinformation information(RAI) (RAI) pertaining pertaining to to the the High High Energy Line Break (HELB) analysis and an (HELB) analysis an audit audit to to complete complete their their detailed detailedreview review ofof the the power uprate. The Theresponse responsetotothis thisRAI RAI was was provided provided in in Reference Reference 3. 3. OnOnJulyJuly17 17and and 18, 2013, the NRC NRC conducted conducted the theaudit.
audit.As Asfollow-up follow-up to to this this audit, audit, inin Reference Reference44the the NRC requested NRC requested additional additional information information regarding regarding the the assumed assumedTurbine TurbineBuilding BuildingHELB HELB break locations.
locations. Specifically, Specifically, the the NRC NRC requested requestedEGC EGCtotoprovide providethe thefollowing following information:
"Describe in "Describe in detail the postulated piping failures and their locations utilized utilized for the analyses of M&E WE release releasefrom frompiping pipinglocated locatedinin the the TBTB that that could could affect affect safety-safety-related equipment located in adjoining adjOining auxiliary auxiliary building rooms rooms and and howhow thisthis information was used used to provide input input the the Gothic Gothic analysis.
analysis. IfIf bounding bounding conditions conditions have been utilized for these analyses analyses identify identify the the piping piping failures failures utilized, utilized, their their bounding M&E WE and andthe thebounding boundinglocations locationsthat thatwould wouldenvelop envelop the the resulting resulting effects on the safety-related safety-related equipment equipment located located in in adjoining adjoining auxiliary auxiliary building building rooms. In addition, justify how rooms. how this/these this/these M&Es M&Es and and location(s) location(s) bound bound others.
others.
This justification This justification should include, include, but is not limited to, to, consideration of of a HEHE release near a HELB damper damper that that would would allowallow pressurization of of room room whilewhile thethe damper is closing while another another room is is not not yet yet pressurizing because because its its damper damper is farther away from the HE release, thereby thereby creating differential differential pressure across the wall that separates separates the the twotwo rooms.
rooms. "
An initial response to the Reference Reference 44 requestrequest was was provided provided in in Reference Reference 5. 5.
The Attachment to this letter letter provides provides additional additional quantitative quantitative detail detail and andinformation information to to the the Reference 4 request request as asdiscussed discussedduring duringaameeting meetingon onNovember November14, 14,2013, 2013,between between EGC (David Gullott, et.al et.al.).) and the NRC NRC (Joel (Joel Wiebe, Wiebe, et.al .).
et.al.).
EGC hashas reviewed reviewed the the information information supporting supporting aafinding finding of of no no significant significant hazards hazards consideration and and the the environmental environmental consideration considerationprovided provided to tothe theNRCNRCin in Reference Reference1.1.
The additional information provided ininthis information provided thissubmittal submittaldoes does not not affect affect the the bases bases for for concluding that concluding that the the proposed license license amendment amendmentdoes doesnotnotinvolve involveaasignificant significant hazards hazards consideration. Furthermore, Furthermore,the theadditional additionalinformation information provided provided in in this this submittal submittal does does affect the not affect the bases bases forfor concluding that neither an environmental impact statement nor nor an environmental assessment needs environmental assessment needsto tobe beprepared preparedininconnection connection with with the proposed amendment.
There are no regulatory commitments contained in in this letter.
letter.
Should youyou have any questions questions concerning concerning this this letter, letter, please pleasecontact contactLeslie Leslie E. E. Holden Holden at at (630) 657-3316.
November 18, 2013 U.S. Nuclear Regulatory Commission Page 3 II declare declare under penalty of of perjury perjury that thatthe the foregoing foregoingisistrue trueand and correct.
correct. Executed Executed onon the the th 18 18th day day of of November November 2013.
Respectfully, 7///l'7~-~~~~'~
David M. Gullott Manager -- Licensing Licensing Exelon Generation Company, LLC
Attachment:
Supplemental Response ResponsetotoNRC NRCRequest Requestfor forAdditional Additional Information Information (Non-Proprietary)
ATTACHMENT SUPPLEMENTAL RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION NRC INFORMATION November 18, 2013 (NON-PROPRIETARY)
Braidwood/Byron Stations MUR LAR Response to RAI RAI November 18, 2013 Attachment, page Attachment, page 11 NRC Request "Describe in "Describe in detail the postulated postulated pipingpiping failures and and their theirlocations locations utilized utilizedfor forthethe analyses of M&E release from piping located in the TB that could affect affect safety-related equipment located in adjoining auxiliary building rooms and and how how this information was used to provide input the Gothic analysis. If If bounding conditions have been utilized for these analyses identify the piping failures utilized, these utilized, their bounding M&E WE and andthe the bounding bounding locations that would envelop the resulting effects on the safety-related safety-related equipment located in adjoining auxiliary building rooms. rooms. In addition, addition, justify how this/these M&Es and and location(s) bound others.
location(s) others. ThisThis justification justification should shouldinclude, include, but butisisnot notlimited limitedto, to, consideration of a HE [high energy] release near a HELB damper that would allow pressurization of of room while the damper damper is closing while while another another roomroom is not not yet yet pressurizing because its damper damper is farther away away from the HE release, thereby creating differential pressure across the wall that separates the two rooms."
Additionally,based Additionally, based on on discussion discussion with the NRC with the NRC on on November 14, 2013, this response response should also also provide provide quantitative quantitative justification justification in lieu of in lieu of engineering engineering judgment to demonstrate demonstrate the approach approach regarding regarding uniform uniform pressurization. The TheNRC NRC specifically specifically noted the example of of the Division Division 11and and 22 Engineered Engineered Safeguards Safeguards Feature (ESF) (ESF) Switchgear Rooms as needing needing to be quantitatively quantitatively validated.
Response
Introduction The Exelon Generation Company, LLC LLC (EGC)
(EGC) Turbine Building Building (TB) (TB) High High Energy Energy Line Line Break Break (HELB)analysis (HELB) analysis considered considered the the potential potential that that the the location location of of aa line line break breakcould couldresult resultininone one damper closing damper closing prior prior to the other, thereby creating creating aa differential differential pressure pressure across acrossthe thewall wall separating two separating two ESFESF divisions.
divisions.
EGC's review review of the divisional wall wall differential differentialpressure pressure concluded concluded that the impact impact of of break break location is location is significantly significantlyless less than than thethe impact impact due to damperdamper performance performance characteristics, characteristics, and andisis well withinthe well within theconservative conservative margins margins contained contained in in the the differential differentialpressure pressure calculations.
calculations. The The technical justification justification for forthis this approach approach is basedbased the thefollowing following considerations.
considerations.
- Pressure Pressure propagates propagatesthroughthroughthe theTBTBairairatatsonic sonicvelocity velocityand andinitiates initiatesclosure closureofofthe the HELB dampers early in the event HELB dampers event
- Pressure Pressure waveswaves travel travel thethe distance distancebetween betweenadjacent adjacentHELB HELBdampers dampersininaamaximum maximumof of 0.05 seconds, seconds,which which isis significantly significantly less than than overall overall damper damper closure closuretimestimes
- There is no direct impact due to equipment blockage between adjacent adjacent dampers dampers Jet Jet Impingement Impingement As described described in in Reference Reference A.1, A.1 , the the comprehensive comprehensivejet jetimpingement impingementanalysis analysisperformed performedby byEGCEGC concluded that that there there were were nonopipepipebreaks breakswithin within 20 20 pipe pipediameters diametersofofthe theDiesel DieselGenerator Generator(DG) (DG)
Room, ESF ESF Switchgear SwitchgearRoom, Room,and andMiscellaneous MiscellaneousElectricElectricEquipment EquipmentRoom Room(MEER) (MEER)HELB HELB dampers dampersthat thatwould would result resultinin aaHELB HELB fluid affecting the fluid jet load affecting the dampers.
dampers. The Thekeykeyresult resultfrom from the jet jet impingement impingement analysisanalysis (Reference (ReferenceA.2) A.2) isis that that none noneof of the theDG DG Room, Room, ESF ESFSwitchgear Switchgear Room, or MEER HELB HELB dampers dampers are are within within the zone zone of of influence influence (ZOl) of a line (ZOI) of line break jet and the the jet pressure pressurewouldwould dissipate dissipateto toambient ambientTB TB pressure pressureprior priorto toreaching reachingaaHELB HELBdamper.
Therefore, damper damper operation operation is is not not influenced influenced by the jet pressure, and and isis instead insteadgoverned governedby by the the bulk bulk TB TB environment.
Braidwood/Byron Stations MUR LAR Braidwood/Byron
Response
Response to to RAI RAI November November 18, 18, 2013 2013 Attachment, Attachment, page page 2 As an As an example of this this conclusion, conclusion, the 10" Main Main Steam Steam (MS) (MS) lineline break break on TB TB Elevation Elevation 426'426' isis presented. This presented. This break break location location is is 5.03 pipe diameters diameters horizontally horizontally and and 4.35 4.35 pipe diameters verticallyfrom vertically fromthe the2VX17Y 2VX1 7Y damper.The damper. Thejetjetimpingement impingementanalysis analysiscalculated calculatedthat that the the distance distance from the break location to the damper from the break location to the damper is greater is greater than 5 pipe diameters, which which is beyond the the jet's jet's ZOI. Therefore, the ZOL Therefore, the jet jetpressure pressure decreases decreases to to ambient ambient TB TB pressure pressurewithin within a much shorter distance than the distance between the distance the break break and and the theHELBHELB damper.
Bulk TB Bulk TB Environment The GOTHIC The GOTHIC analysis analysis (Reference A.3) A.3) determined determined the the time time between betweenthe theinitiation initiationofofthe theHELB HELB event and when TB environment reaches reaches 100% 100%relative relative humidity.
humidity. Utilizing Utilizing the HELB damper HELB damper differentialpressure differential pressure and and closure closure timetime characteristics, characteristics, the GOTHIC GOTHIC analysisanalysis also also determined the time each damper time damper achieves achievesfull full closure closure following following the the initiation initiationofofthe theHELBHELBevent.event. EGC EGC has compared these these times times and and concluded concluded that thatforfor each eachHELB HELB event event where where relative relative humidity reaches humidity reaches 100%, both 100%, both adjacent divisional divisional HELB dampers are HELB dampers are closed closedwellwell before before100% 100%relative relativehumidity humidityisis reached.
reached.
Following the Following the initiation initiation of ofthe the HELB HELBevent, event, prior prior toto reaching 100% 100% relative relativehumidity, humidity, the thebulk bulkTB TB environment outside environment outside the the HELB HELBdampersdampers is is air, air, as as opposed to to aa steam-air steam-airmixturemixture or or pure pure steam, steam, and behaves as as an an ideal ideal gas.gas. Therefore, Therefore,when when the the HELB occurs, the HELB occurs, the mass and energy released intointo the TB from from the the line line break break displaces displaces the air surrounding the break location. location. TheThe displacement of air air creates creates a pressure pressure increase increasethat thatpropagates propagatesthrough throughthe theTBTBvolume volume at atsonic sonic velocity (i.e.,
velocity (i.e., sonic sonic pressure pressure wave).
Sonic Pressure Wave Impact Impact EGC has calculated the effect EGC effect of this this sonic pressure pressure wave wave on on HELB dampers' closure; HELB dampers' closure; specifically the specifically the time time the the sonic sonic pressure pressure wave wave will travel the will travel the distance distance from from the break break location location to each of of the adjacent adjacent HELB HELB dampers (Reference (Reference A.4). A.4). ThisThistime time isis aafunction function of of the speed speedof of sound in in air air and and the the distance distancetraveled traveledto toeach eachHELBHELBdamper.
damper.At AtBraidwood Braidwood and andByron Byron Stations, Stations, the distance distance is is bounded bounded by by the the 5858feet feetbetween betweenthe theDivision Division 11 and and22ESF ESFSwitchgear SwitchgearRoom Room dampers on Elevation dampers on Elevation 426'. The calculated difference The calculated difference for for sonic pressure waves pressure waves to travelto travel through the TB Elevation Elevation 426' air from from thethe break to the adjacentadjacent HELB dampers isis 0.0422 HELB dampers 0.0422 seconds.
seconds. This Thisvalue valueisisconservatively conservatively rounded rounded up upto to 0.05 0.05seconds secondsthroughout throughoutthe theremainder remainderof of the evaluation.
evaluation.
EGC hashas quantified quantified the the differential pressure across differential pressure acrossthe thedivisional divisional wallwall between between ESF ESFSwitchgear Switchgear Rooms that corresponds to a 0.05 second time delay in in adjacent adjacent damper response. Using USingthethe GOTHIC analysis for GOTHIC analysis for the the 10" 10" main main steam steam line break on TB Elevation 426', the 0.05 0.05 second secondtime time difference in localized localized TB TB pressurization pressurization outside the adjacent adjacent HELB HELB dampers dampers translates translatestotoaa differential pressure across differential pressure across the thedivisional divisional separation separationwall wall ofof 0.0031 0.0031 psid psid(Reference (ReferenceA.4). A.4).
Consideration Consideration of of Equipment Eguipment Blockage Blockage EGC has has determined determined there thereisis no noimpact impact on on the thepropagation propagationof ofthe thesonic sonicpressure pressurewave wavethrough through the the TB TB environment due to blockages or or obstructions.
obstructions. There Thereisisno nolarge largeequipment equipmentororwalls walls located located between between adjacent adjacent HELB HELB dampers. Similar Similar to to sound sound waveswaves in in air, air, the sonic sonic pressure pressure wave wave will move around small obstructions and will move and blockages blockageswithoutwithout impact impact on on its its propagation propagation through through thethebulk bulkvolume.
volume.
Analyzed Analyzed Divisional Divisional Wall Wall Differential Pressure Differential Pressure The The GOTHIC GOTHIC analysis performed by EGC EGC calculated calculated the the bounding bounding differential differential pressure pressureacross across each eachof of the the divisional divisional walls based on walls based on differences differences in in damper damper closure closure characteristics.
characteristics. This This
Braidwood/Byron Stations MUR LAR Braidwood/Byron
Response
Response to RAI November 18, November 18, 2013 Attachment, page Attachment, page 3 analysis involved maximizing analysis maximizing the the closure time of one HELB HELB damper and and minimizing minimizing the closureclosure time of time of the the adjacent adjacent HELB HELBdamper. damper. EGC EGC usedused the thedesign designmaximum maximum HELB HELB damper cycle time to close to close ofof 0.5 0.5 seconds seconds and determineddetermined minimum minimum damper cycle cycle timetime to to close close based based on empiricaltest empirical test measurement measurement uncertainties uncertainties and and damper damperperformance performancevariations.
variations.
For the For the case case ofof the 10" 10" main steam steam line line break breakin in TB TB Elevation Elevation 426', the the differential pressure differential pressure across thethe ESF ESF Switchgear Switchgear Room Room divisional divisional wall wall due due to to damper closure characteristics was was calculated to calculated to be be 0.0490 psid psid inin the the GOTHIC GOTHICanalysis.analysis. Using Using thethe same same damper damper closure characteristics, the GOTHIC GOTHIC analysis analysis calculated calculated the highest differential pressure across this differential pressure ESF Switchgear Room divisional wallto divisional wall to be be 0.0659 0.0659 psid, which which is is created by the 26" Heater Drain line Drain linebreak break on on TB TB Elevation Elevation451'. 451'. However, However, this break is is not not located located local local to to one one ofof the the HELBdampers, HELB dampers, therefore therefore the the sonic sonic pressure wave wave time time delay in damper closure would would be lessless than 0.05 than 0.05 seconds.
In addition In addition to to the the differential differentialpressure pressure resulting resulting from fromthe the damper damper closure characteristics, the the GOTHIC analysis GOTHIC analysis alsoalso considered the the differential differential pressure pressure created createdfrom from the theoperation operationof ofthe the AuxiliaryBuilding Auxiliary Building(AB) (AB)room roomventilation ventilationsystem.
system.This Thiscalculated calculateddifferential differentialpressure pressure is is based based on one division's division's ventilation in operation and and the the other otherdivision's division'sventilation ventilation shutdown.
shutdown.
Margins There are are significant significant margins margins and andconservatisms conservatismsincluded includedininthe theGOTHIC GOTHICanalysis analysisdifferential differential pressure calculations pressure calculations due to damper damper performance performance and and ventilation operation. As ventilation system operation. As demonstrated below, demonstrated below, these these margins marginsencompass encompassthe therelatively relativelyinsignificant insignificant impact impact of the differentialpressure differential pressure created by the time delay due to the sonic sonic pressure pressurewave wavetraveling traveling through through the TB TB environment.
In order In order toto maximize maximize the the time time one one damper remained remained open open while while itsits corresponding corresponding adjacentadjacent damper was closed,closed, EGC EGC evaluated evaluated the the empirical empirical test measurement measurement uncertainties, uncertainties, damperdamper performance variations, and additional margin. margin. Each Each set setofofadjacent adjacentHELB HELB dampers damperswas was evaluated to determine the specific the specific stroke time time difference for the pair of dampers.
for the pair of dampers. This This information information was was used used in in the the GOTHIC GOTHIC analysis analysis to to maximize maximize differential pressure on differential pressure onthe the associated associateddivisional divisional separation separationwall. wall. Using Usingthisthisinformation, information, the theminimum minimum marginmargin and and uncertainties for any set of of dampers dampersisis 35% 35%of of the the maximum maximum design designdamper dampercyclecycletimetimeof of0.5 0.5 seconds; seconds; overover21 21% % represents representsactual actualmargin margin(Reference (ReferenceA.4). A.4).
As calculated previously, previously, the maximum damper damper closureclosure delay delaytimetime between betweentwo twoadjacent adjacent dampers dampers due dueto tothe thesonic sonicpressure pressurewavewavetraveling travelingthroughthroughthe theTB TBenvironment environment isis 0.05 0.05 seconds.
seconds.
This time delay is is only only 10% of the maximum maximum design design damper dampercycle cycletimetimeandandwithin within thetheminimum minimum 21 % % margin margin calculated calculated for for damper damper performance.
performance.
An additional additional source of margin for for the the calculated differential pressures in the ESF differential pressures ESF Switchgear Switchgear Rooms and and the theMEERs MEERs isis due dueto tothe theuseuseofofthethebounding boundingDiesel DieselGenerator Generator(DG) (DG)ventilation ventilation system system parameters parametersininall all differential pressure calculations.
differential pressure calculations. The Thedifferential differential pressure pressurecreated created from the operation operation of of one onedivision division ofof DG DG ventilation ventilation while while the otherother division division isis shutdown shutdownisis 0.0451 psid.
psid. This Thisdifferential differential pressure pressureboundsboundsthe thedifferential differential pressure pressurecreated createdby bythe theindividual individual room ventilation systems for the ESF ventilation systems ESF Switchgear Switchgear Rooms Rooms and andMEERs.
MEERs.The TheGOTHIC GOTHICanalysisanalysis conservatively conservatively applied applied this thisbounding boundingDG DGventilation ventilationdifferential differential pressure pressuretotoall allthe thedivisional divisionalwall wall differential pressure calculations.
differential pressure calculations. When compared compared to to the the actual actual ESF ESFSwitchgear SwitchgearRoom Room ventilation ventilation system differential pressure of differential pressure of 0.0204 psid, psid, this this approach approachresults resultsininan anadditional additional 0.0247 0.0247 psid psid margin margin in in the the differential pressure calculation differential pressure calculation (Reference (Reference A.4). A.4). This Thismargin marginisis significantly more than significantly more than the 0.0031 psid created createdby bythe thesonic sonicpressure pressurewave waveininthe theTB.TB.
Braidwood/Byron Stations MUR LAR Braidwood/Byron Response to RAI November 18, 2013 Attachment, Attachment, page page 4 AA summary summary of of the the margins in the GOTHIC GOTHIC analysis analysis for for the divisional divisional separation separation wall wall between between the ESF Switchgear Rooms is is provided provided in in Tables 1 and 22 below: below:
Table 11 NO-DP due to maximum time delay for adjacent TB damper closure due to 0.0031 -----
sonic pressure propagation (0.05 sec)
HELB DP due to damper characteristics and tolerance for 10" MS line 0.0490 >0.0031 break on TB Elevation 426' HELB DP due to damper characteristics and tolerance for 26" HD line 0.0659 >0.0031 break on TB Elevation 451' (bounding break for ESF Switch ear walls)
DP due to DG ventilation system operation 0.0451 0.0247 0.0031 psid is about 6% of 0.0490 psid and equates 0.0031 equatesto to approximately approximately 0.09 0.09 inch inch wg.wg.
Table 2
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'"+ , ,w- v:, ^ ^J^ a ^^ {:. '.,'S- "=*^; ^^i'3^^e s .: ^^"`a Z'"M e^ V'w"c G "` ;^%n ^ _ "r`^ .^.
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l^ ii' s"r v' "'s ^
10" MS line 10" line break on on TB Elevation Elevation 426' (Reference (Reference A.3) A3)
(DG ventilation ventilation DP DP (0.0451 (0.0451 psid) psid) and DP due to 0 . 0941 0.0941 N/A characteristics and tolerance (0.0490 damper characteristics (0.0490psid)) psid))
26" heater drain 26" drain line line break break on on TB TB Elevation Elevation 451' (Bounding break in GOTHIC analysis) in GOTHIC analysis) (Reference A.3) A3)
(DG ventilation ventilation DP DP (0.0451 (0.0451 psid) psid) and DP due due to 0.1110 0.0169 characteristics and tolerance (0.0659 damper characteristics (0.0659psid)) psid))
ESF Switchgear Switchgear Room Room structural structural analysis analysismaximum maximumwall wall design DP (Reference A.5) A5) 0.1318 0.0208 Conclusion EGC's evaluation has determined determined the the maximum maximum time delay in local local TB TB pressure pressure due to to the distance between HELB HELB dampers dampers is 0.05 seconds. The Thedifferential differential pressure pressureacross acrossDG DGRoom,Room, ESF Switchgear Room, and and MEER MEER divisional separation walls, created divisional separation created as asaaresult resultofofthis thistime time delay, has has aa veryvery small small contribution contribution to to the the overall overall calculated calculated differential differentialpressure. pressure. EGC has has quantitatively quantitatively demonstrated demonstrated that that this this 0.05 second time delay contribution contribution is is encompassed encompassed by by the the significant significant margins and conservatisms conservatismsin inthethedivisional divisional wall wall differential differential pressure pressure calculations.
calculations.
Therefore, EGC's EGC's approach approachconsidering considering the theuniform uniform pressurization pressurizationof of the theTB TB isis technically technically justified through justified through analysis analysis and is consistent is consistent with with the Braidwood Braidwood and Byron Byron design and and licensing licensing basis basis requirements.
requirements.
Braidwood/Byron Stations MUR LAR Braidwood/Byron
Response
Response to to RAI RAI November 18, November 18, 20132013 Attachment, Attachment, page page 5 References References A.1. Letter A.1. Letter from from David David M.M. Gullott Gullott (Exelon (Exelon Generation Company, Company, LLC) to U. S. NRC, "Supplemental "Supplemental Response Response to to NRC NRC HELB HELB Audit Audit Request Request for Information InformationSupporting Supporting Request Request for License for License Amendment Amendment Regarding Measurement Measurement Uncertainty Uncertainty Recapture RecapturePower PowerUprate,"
Uprate,"
dated October 8, dated 8, 2013 A.2. Byron/Braidwood A.2. Byron/Braidwood Calculation Calculation No.
No. BYR1 3-078 / BRW-1 BYR13-078 3-0023-M, "Turbine Building BRW-13-0023-M, Building HELB HELB Jet Impingement on Auxiliary Building Openings," Rev.
Jet Rev. 0, 8/23/13 A.3 Byron/Braidwood A.3 Byron/Braidwood Calculation Calculation No.
No. BYR12-070 BYR12-070/ /BRW-12-0084-M, BRW-12-0084-M,"Auxiliary "Auxiliary Building Building Environment Following Environment Following a High Energy LineLine Break Break in in the the Turbine TurbineBuilding,"
Building," Rev.
Rev. 1, 1, 7/3/13 7/3/13 Byron/BraidwoodEngineering A.4 Byron/Braidwood Engineering Technical Technical Evaluation Evaluation ECEC 396096, 396096, "Supplemental Information for NRC RAI Information for NRC RAI on on TB HELB Analysis," Rev. 0, 11/18/13 Rev. 0,11/18/13 A.5 Byron/Braidwood Transmittal Transmittal of of Design DesignInformation Information(TODI)
(TOOl)No. No.BYR-13-005 BYR-13-005/ /DIT-BRW-DIT-BRW-2013-0007, Rev. 0, 2/1/13