Text

Flood Hazard Mitigation Strategies Assessment
	ML17033A340
Person / Time
Site:	Wolf Creek
Issue date:	03/15/2017
From:	Lauren Gibson; Japan Lessons-Learned Division
To:	Heflin A; Wolf Creek
	GIBSON, LAUREN NRR/JLD 301-415-1056
Shared Package
ML17033A334	List: ML17033A340;
References
	CAC MF7992
	Download: ML17033A340 (11)
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OFFICIAb YSE ONL¥ SECYRIT¥ RELATED INfORMATIO~

UNITED ST ATES NUCLEAR REGULATORY COMMISSION

.WASHINGTON, D.C. 20555-0001 Mr. Adam C. Heflin President, Chief Executive Officer,

and Chief Nuclear Officer Wolf Creek Nuclear Operating Corporation P.O. Box 411 Burlington, KS 66839 March 15, 2017

SUBJECT:

WOLF CREEK GENERATING STATION - FLOOD HAZARD MITIGATION STRATEGIES ASSESSMENT (CAC NO. MF7992)

Dear Mr. Heflin:

By letter dated March 12, 2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML12053A340), the U.S. Nuclear Regulatory Commission (NRG) issued a request for information to all power reactor licensees and holders of construction permits in active or deferred status, pursuant to Title 1 O of the Code of Federal Regulations (10 CFR), Section 50.54(f), "Conditions of Licenses" (hereafter referred to as the "50.54(f) letter"). The request was issued in connection with implementing lessons learned from the 2011 accident at the Fukushima Oai-ichi nuclear power plant, as documented in the NRC's Near,;.Term Task Force (NTTF) report (ADAMS Accession No. ML111861807). to the 50.54(f) letter requested that licensees reevaluate flood hazards for their sites using present-day methods and regulatory guidance used by the NRC staff when reviewing applications for early site permits and eombined licenses (ADAMS Accession No.

M.L 12056A046). Concurrent with.th,e reevaluation of flood hazards, licensees.were required to develop and implement mitigating strategies in accordance with NRG Order EA-12-049, "Order Modifying Licenses with R.egard to Requirements for Mitigatio.n Strategies for Beyond-Design-Basis External Events" (ADAMS Accession No. ML12054A735). In order to proceed with implementation of Order EA-12-049, licensees used the current licensing basis flood hazard or

. the most recent flood hazard information, which may not be based on present-day methodologies and guidance, in the development of their mitigating strategies.

I By letter dated November 8, 2016 (ADAMS Accession No.. ML16321A424),

Wolf Creek Nuclear Operating Corporation (WCNOC, the licensee) submitted the mitigation strategies assessment (MSA) for Wolf Creek Generating Station. The MSAs are intended to confirm that licensees have adequately.addressed th.e.reevaluated flooding hazards within their mitigating strategies for beyond-design~basis external events. The purpose of this letter is to.*

provid~ the NRC's ass~ssment of the Wolf Creek MSA.

Enclosure* 1

t.r<:msmitted herewith contains* Security*Jlelated Information. When separated.*

from Enclosure t, this document is decontrolled.

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OFFICIAL USE ONLY SECURITY RELATED INFORMATION A.. Heflin

The NRC staff has concluded that the Wolf Creek MSA was pe(formed consistent with the guidance described in Appendix G *at Nuclear Energy Institute 06, Revision 2, as endorsed by Japan Lessons-Learne_d Division (JLD) interim staff guidance (ISG) JLD:-ISG~2012-01, Revision 1, and:that the licensee -has demonstrated that the mitigation strategies are reasonably protected from reevaluated flood hazards conditions for beyond~design-basis external events.

This closes out the Nl;lC's efforts associated with CAC No. MF7992.

If you have any questions, please contaci me at 301-415-1056 or at Lauren.Gfbson@nrc.go~. **

Enclosures:

1.. Staff Assessment Related to the Mitigating Strategies for Wolf Creek (non-public)

2. Staff Assessment Related to the Mitigating Strategies for Wolf Creek (redacted)

Oocket No. 50-482 cc w/encl: Distribution via Listserv Sincerely, Lauren K. Gibson, Project Manager Hazards Management Branch.

Japan Lessons-Learned Divi~_icm Office of Nuclear Reactor Regulation *

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OFFICIAL USE ONLY SEOURln< RELATED INFORMATION

.. STAFF ASSESSMENT BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO MITIGATION STRATEGIES FOR WOLF CREEK GENERATING STATION, AS A RESULT OF THE REEVALUATED FLOODING HAZARD NEAR-TERM TASK FORCE RECOMMENDATION 2.1-FLOODING CAC NO. MF7992

1.0 INTRODUCTION

By letter dated March 12, 2012 (Agencywide* Documents Access and Management System (ADAMS) Accession No. ML12053A340), the U.S. Nuclear Regulatory Commission (NRC) issued a request for information to all power reactor licensees and holders of construction permits in active or deferred status, pursuant to Title 10 of the Code of Federal Regulations (1 O CFR), Section 50.54(f), "Conditions of Licenses" (hereafter referred to as the "50.54(f) letter). The requestwas issued in connection with implementing lessons learne.d from the 2011 accident at the Fukushima Dai-ichi nuclear power plant, as documented in the NRC's Near-Term Task Force (NTTF) report (ADAMS Accession No. ML111861807). to the 50.54(f) letter requested that licensees reevaluate flood hazards for their sites using present-day methods and regulatory guidance used by the NRC staff when reviewing applications for early site permits and combined licenses (ADAMS Accession No. ML12056A046).

Concurrent with the reevaluation of flood hazards, licensees were required to develop and implement mitigating strategies in accordance with NRC Order EA-12-049, "Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis E;xternal Events" (ADAMS Accession No. ML12054A735). That.order requires holders of operating reactor licenses and construction permits issued under 10 CFR Part 50 to modify the plants to provide additional capabilities and defense-in-depth for responding to beyond~design-basis external events, and to submit to the NRC for review a final integrated plan that describes how compliance with the requirements of Attachment 2 of the order was achieved. In order to proceed with implementation of Order EA-12-049, licensees.used the current licensing basis (CLB) flood hazard or the most recent flood hazard information, which may not be based on present-day methodologies and guidance, in the development of their mitigating strategies.

The NRC staff and industry recognized the difficulty in developing and implementing mitigating strategies before completing the reevaluation of flood hazards. The NRC staff described this issue and provided recommendations to the Commission on integrating these related activities in COMSECY-14-0037, "Integration of Mitigating Strategies for 13eyond-Design-Efasis External Events and the Reevaluation of Flood Hazards," dated. Noyeniber 21, 2014 (ADAMS Accession No. ML14309A256). The Commission issued a staff requirements memorandum on March 30, 2015 (ADAMS Accession No. ML15089A236), affirming that the Commission expects licensees for operating nuclear power plants to address the reevaluated flood tiazards, which are

'considered beyond-desigff*basis external events, within th.~ir mitigating strategies~'

*

Nuclear Energy Institute (NEI) 12..:oa, Revision 2, "Diverse and Flexible Coping Strategies

(FLEX) Implementation Guide (ADAMS Accession No. ML16005A625), has been endorsed by the NRC as an appropriate methodology for licensees to perform assessments of the mitigating OFFICIAL USE ONL¥-SECURIT'f RELATED INFORMATION

OFFIGI~~ U~.~ ONLY

8~GUfllI¥ RELAT~p INFORMATION 50.54(f) letter. The guidance* in NEI 12-06,Hevision.2, and Appendix Gin particular, supports the proposed Mitigation of Beyond-Design*~~asis Events rulemaking. The NRC's: endorsement ofNEI 12-06,*including exceptions, clarifications, aod adc;Utions, is descrioed in NRC Japan Lessons-Learned Division (JLD) interim staff guidance (ISG) JLD-ISG-2012-01, Revision i, "Compliance with Order EA~12~049, Ordedviodifying License~ with.R~gard to Req1.:1irements for Mitigation Strategies for Beyond~Design-Basis EXternal Events" {ADAMS Accession No.

M.L 15357A16=3). Th~refbre, App~ndix G of NEI 12-06,"Revlsion 2, describes acceptable methods for. demonstrating tha~. the reevaluat.eQ.flooding hazard is addressed within the Wolf Creek ~enerating Statio'n (Wolf Creek) mitigating strategies for beyond-design-basis external events.

2.0 BACKGROUND

By letter dated March 10, 2014 (ADAMS Accession No. ML14077A280), as supplemented by letter dated May*20, 2015 {ADAMS*Accession No. ML15147A516), Wolf Creek Nuclear Operating Corporation {WCNOC, the licensee) submitted its flood hazard reevaluation report (FHRR). Th.e licensee provided ~ revis.~d FHRR on January 19, 2016 (ADAMS Accession No. ML16032A189). BY letter dated Decem,ber 24, 2015 (ADAMS Accessio.n No. ML15357A180),

the NRC issued an interim staff response (ISR) letter for Wolf Creek. The ISR letter provided the reevaluated flood hazard mechanisms that exceeded the current design basis (GDB) for Wolf Creek and flood parameters that are suitable input for the mitigating.strategies assessment (MSA). ForWolf Creek, the mechanisms listed as not.bounded by the CDB in the ISR letter are local intense precipitation (LIP) and failure of dams and onsite water control/storage structure.

By letter dated November 8, 2016 (ADAMS Accession No.. ML16321A424}, WCNOC submi~ed the Wolf Creek MSA for review by the NRC staff.

3.0

.TECHNICAL EVALUATION 3.1 Wolf Creek's FLEX Strategies The licensee stated in its MSA that Wolf Creek's FLEX strategy is described in the document,

V\\f olf Creek Nuclear Operating QC?rporation Overall Integrated Plan in ~~sponse to March 1 ?-..

2012 Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number-EA-12-049F1 The licensee's fiood evaluation for FLEX accounted for all flood hazards with the exception of the LIP flood and. Upstream Dam Failure from the Neosho River flood even:t as di.s:cussed in the Wolf Creek's FHRR document. The licens.ee stated. in its MSA that the FLEX strategies would not be imp~cted by the ~hove flood events.

A brief summ~ry of tlie licensee's FLEX strategies is as follows:

*For-Phase 1, decay he.a.tis removed via steam release to the.atnio5phere through the SG AtmosphericValv~s (ARVs). The Turbine Driven Auxillar}t Feedwater (TDAFw) pump w.il! provide makeup flpw to the SGs, taking s:l;Jction from lhe: Condensate Storage*

Tank (C.ST). N?tU.rctl ~irculation is maintained in the reactor cool~nt system ffl.C:~fas 1 SLlbsequeiitly, the licens~~* pro~ided the. final *integrated :plan tor:.wolf Greek by l~ttet ciat~ci January 191

2617 (ADAMS.'Accessi6.n No. ML 17()26A 194). The NRCfa1~.ittt is:~valuating thWsirategies in the plan and. :

will document the review !!1 *~ saf~ty evaruatiori:. The p!;Jrpose* ofth~ :~afety ~valuation is to. ~nsure the Hcen.set: has *dev~loped g:uidi:int:e :and proposed desigfls which, if irt)plemented appropri~t~ly; ~ill

.

a~~uately address the. req'Uirenients of Ord~r, EA~12~049. A.Ii !n~pe~tidil will confirm compliance ~~h th~. ::..

order.

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. ()FFICIAL USE ~tJLY SECURITY RELATED INFORMATION operators cool the :plant Operators take actions (shed loads) to prolong the vital battery life.

For Phase 2, SG makeup*would*be via a FLEX core cooling pump~ whfoh is staged*

within 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months .. Around the ts hour mark, make*up to the CST is inltici.ted from the Ultimate Heat Sink (UH.S). A FLEX generator is also deployed by the 8 hour9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months mark to.

power the battery chargers or other loads. RCS makeup is initiated around the 14 hour1.62037e-4 days 0.00389 hours 2.314815e-5 weeks 5.327e-6 months mark via a FLEX RCS Ma,keup pump taking suction from the Boric; Acid Tank (BA tj.

Around the 43 hour4.976852e-4 days 0.0119 hours 7.109788e-5 weeks 1.63615e-5 months mark, the BAT is depleted and the FLEX RCS pump is aligned to the Refueling Water Storage Tank (RWST}. Si=P makeup is initiated around ttie 34 hour3.935185e-4 days 0.00944 hours 5.621693e-5 weeks 1.2937e-5 months mark via a FLEX SFP Makeup pump taking suction from the UHS (through the csn.

For Phase 3, the licensee will receive equipment from the National SAFER Response Center (NSRC) to continue the same FLEX strategies from Phase 2. The equipment will not be impacted since Phase 3 starts 24 tiours into the event, at the earliest, and is not required to be implemented until 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .

3.2. Evaluation of Flood Pr.otection Features LIP Flood MSA Section 2.1 described the reevaluated LIP as a maximum flood height of 1, 100.5 ft. mean se.a level (MSL) around the power block. The COB LIP flood around the power block is 1,099.9 ft. MSL. The MSA indicated that there are 11 door sill locations, designated as pathways for safe :shutdown equipment, where the elevation would be exceeded by LIP flood water for up to 1.23 hours2.662037e-4 days 0.00639 hours 3.80291e-5 weeks 8.7515e-6 months before receding from the power block area, based.on the calculations provided. in the Wolf Creek FHRR. The licensee stated in the MSA that the results of the revised LIP will require an i.nterim action of instructing operators to place quic;l< qarn barriers at the above door sill locations to protect the areas with the safe shut down equipment from the any potential water penetratiofl thrc;>ugh the door sills.. The licens13e ~tc;ited in the M~A* that the revised LIP flood event would allow for a minimum of one~hour warning time to deploy the. quick dam barriers p.rior to the event.: The interim acti.c;>n will ~e hi place u~til the licensee completes physical modifications around. the plant site. to all.ow for water <]iversion up to the new maximum flood height. The quick dam barrlerswill be placed :ih.fhe buildings in which the affected door sills are located.* The licensee indicated in the MSA that the revised LIP fiood event would not cause an ELAP event 0)'1 site. The licensee assumed that the LIP flood would begin 90 minutes after the FLEX initiating event ha~.occurred. *The overall FLEX strategy does not require any additional operator a~tions for at: le~st 6: tiours, when* formal damage a$s~ssrnent of the site is comf)leled. The licensee concluded in the MSA that the current FLEX strategies for deploying FLEX equipment for Phase 2 would not be impacted by the revised UP flood ev~h..iation due to the time niargin accounted in the.overall. strategy, which is much greater than *ttie 1.23 hours2.662037e-4 days 0.00639 hours 3.80291e-5 weeks 8.7515e-6 months needed for the LIP flood to recede from the power block area.

The NRC staff reviewed the licensee's assessment of the reevaluated LIP event *as compared to existing FLE)(~trategies in the W9lf Creek OIP. The NRC $taff finds th:a~ acjcc)1:-1nting for th~ PP flood o~curring after the EL.AP.event, that t.here will be *about 4.5 hour5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months s* available befpre formal site assessment for FLE)(deployment is required. The margin ailows more than adeq'.uate time to account for a: LIP ti.odd event a.nd evEmtual: recessJon to C!,lloW :for* suc;:c;:es~fµ! ~eplbym:em. of

. FlE)( equipm*ent to the designated area.S within the. power block. The NHC staff also. noted that.*:*

the ligensee will use* th~. i~terin} action of pro111pting operators to: place quick dam. bat(i~rs at' the doot:sillpathways wher¢ lhe ~afe shutdown equipment are located. *This interim* action: would nqt impact the :f:LEX deployment strategy since the quick ~am barriers. W()Uld.be deployed.o.ne

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... hour before the LIP flood event. Based on the time available to initiate site assessment and flood protection actions *after the ELAP event, the N RC staff fhids the licensee has adequately assessed the*MFSHI for the LIP flood event and that the applicable FLEX strategies can be

. implemented as described in the OJP.

Upsfream Dam Failure from the Neosho River MSA Section 2.2 described the reevaluated hazard elevation for Failure of Dam$ aod Qnsite WatEfr Control/Storage Structures a due to the potential for Upstream Dam Failure from the Neosho River. This flood elevation is higher than the CDB*h11zard elevation of The Wolf Creek site grade at safety-related buildings is 1,099.5 ft. MSL, which gives a flood elevation margin o The licensee further stated that the topographical features in the area of Coffey Courity Lake would not allow the flood waters to reach the Wolf Creek site. Therefore, the licensee ruled out the upstream dam failure from the Neosho River as a credible flood *hazard for Wolf Creek.

T~e NRC that the licensee has adequately assessed the upstream dam failure mechanism for the impact on the FLEX strategies and that the applicable FLEX strategies can be implemented as currently: designed.

Conclusion The NRC staff has reviewed the information provjded in the Wolf Creek MSA related to the original FLEX strategies, as evaluated against the reevaluated hazards described in Section 3.2.3 of this Staff Assessment, and f~und that the licensee nas adequately assessed the MFSHI for the.reevalliated UP and. the Upstream Pam Failure from the Neosho River flood events to determine.that the FLEX Strategy can be frnplemented as currently designed. The NRC staff made its deter:minaticm.based upon:

TirnE? margin ava.ilable tQ deploy Fl,.,t;:x 9q4ipnient after the.U.P flood water has receded fro.ni the power block area;

interim *action of placing quick dam barriers with one hour warning time prior to the LIP flooq' event to pr~tect the door sills before FLEX equipment is deployed and staged; Flood 10~els not reaching.she grade for Upstream Dam Failure from th.e Neosho River flood events..

. Therefore, the N.RC staff concludes that' the licensee has demonstrated the capabil.ity to dep)oy

FLEX strategies, as modified, against a postulated beyond-design-basis event for the above flood:everits, as described in NEI 12-06, Revision 2 arid ISG-2012.,.01, Revision 1.

3.3 Evaluation of Flood Event Duration Regardihg tile flood event: duration (FED) *parameters neededfo perform the MSA.forflood

. ha,?ard~ not *~9unq~d by the curr:~rit qesjgot>asis* (Cl?.E}), ~hE? staff revi~vy~d information *pr9vide.Q...

by WCNOC in the FHRR (Rev 1 ),: tlie MSA, and th~ response to a requestfor additional information: dated May 20; 2015. (ADAMS Acciession No. ML15147A516): ** The FED ~arameters for the flob(J'~causing m~'c~anisms notbou:tloed'by.the CDB a:re summarized in T~b.le *3.3.

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For the. LIP.event, the licensee stated that the flood water maintains.a depth above: 1 i door sills that are pathways to safe' shutdown equipment for a period of lni.mdation up to 1.23 hours2.662037e-4 days 0.00639 hours 3.80291e-5 weeks 8.7515e-6 months after

the start of the LIP rainfall based on the calculations used to develop the fHRR. The licensee*

defined a war.nirig time of 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months and a period of recess[on'CJf R76 hours. For the LIP event floo~ir19, th~ maximum water elevations and inundation perio~s for -~iffererit locations across the power block are listed in Table 3-3 of the FHRR, Rev 1. The.licensee used results from a 2-dimentional numerical modeling method to determine the inundation duration and period of recessi.011 parameters. The staff confirmed that the licensee's reevaluation of the inunq1;1tiori periods for LIP and associated drainage uses present-day methodoiogies and regulatory guidance.

For dam:failure, the licensee used the volume method which assumes to transport the total upstream reservoir storage volume instantaneously, and conservatively, to the WCNOC plant site without attenuation. As a result, the licensee found that a flood elevation margin for this postulated dam failure event is-Due to topographical teatures in the area of Coffey County Lake, results from the volume method do not encroach into the lake such thatth.e flood waters postulated by the volume method never approach the site as shown by Figure 3-1!5 of the FHRR. B~sed ori this information, the licensee screened out dam failure fr.om further evaluatian in the FHRR. Correspondingly, the licensee concluded that upstream dam failure from the N~osho River is not a credible hazard for further consiqeraticm in the MSA, and that the FED parameters. for this flood causing mechanism are not applicable. The staff noted that the licensee's application of the volume method follows guidelines provide by the Interim Staff Guidance (ISG)'tordarrifailure (ADAMS Accession No~ ML13151A153). Therefore, the staff agrees with the licensee's conclusion that the FED parameters for dam failure are appropriate for the purposes of the MSA..

In summary., the staff agrees with the licensee's conclusion related to determining the* FED parameters, a$the approach is consistent with the guideli.ne provided by Appendix G of NEI 12-06, Revision 2, Based on this review, the staff determined that the licensee's FED parameters are reaso.naJ;>le and acc.eptab!~ for use in the MSA.

3.4 Evaluation of Associated Effects The staff.reviewed the information provided by WCNOC regarding re.evaluated associated e~ects (AE) pa~meters for flO'od hazards not bounded by the CDB. The AE parameters rel~tetj to.water surface.elevatio.n (i.e., stillwater elevation with wind waves and runup effects) wer.e previously reviewed by staff, and were transmitted to the license~ via tlie ISR. The AE para~E;lters not directly. ~ssociated with water surface elevation are discussed below and are summarized in. Taple 3.4.

For tne LIP event, the liGensee provided the estimation of the hydrostatic and hydrodynamic loads in the FHRR. This estimation is based on the result of a 2-dimentional numerical' modeling met.ho~ i::l.S ~ascribed in fHRR. The licensee alsq stated thattne other associat$µ.

effects, including ~ei:fiment deposition and erosion, debris, groundwate{ingress, and other:

associated :effects, were s.cieened out because the associate effects of them are. minimal due to sh.C111o.~ flow d~p~h.s, xeli:i.tii.!ely:slow flow velocities; ~.nd the floW:airectiqns, which aie.away frorp.

safety-related :strl.idtures, systems and. components;;:HoW0,ver', they reported the concurrent site:

condition for Winds of 3.8:.65.miles per hour in the.MSA: Th:e s.t~ff confirmed the ljp~nse~*s statemerits~by reviewing: the licensee-provided LIP model's input and output files;: The staff*

verified that tll.fi.im.mqation depthe;.an_(j flow velocities.are: accurate and _the modeli~g is OFFICIAL USE ONLY SECURITY RELATED INFORMATION

0FFICl!\\L l_JSE ONLY SECURITY RELAt;D.l~FQRMATIO~. reasonable for use as part of the MSA. Correspondingly, the staff agrees with the licensee's assessment of the AE parameters for LIP..

For the hydrologlc dam failure event, the licensee concluded that upstream dam failure from the Neosho River is not considered a credible hazard for further consideration in the-MSA, and that the FED parameters forth.is flc)od-causing' m"echanism are not applicable. The staff noted that the licensee's* :appiication of the volume method follows guidelines provided by the ISG for dam failure analysis. Correspondingly, the staff agrees with the licensee's conclusion regarding the FED parameters for the* darri failure event.

In summary, therstaff concludes the licensee's methods were appropriate and the AE parameter results are reasonable for use in the MSA.

4.0 CONCLUSION

The NRC staff has reviewed the information provided in the Wolf Creek MSA related to the FLEX strategies, as evaluated against the reevaluated. hazard(s) described in Section 2 of th.is staff assessment, and found that:

1 The FLEX strategies are not affected by* the i.mpacts of the ISR flood levels (including impacts due to the environmental conditions created by the ISR flood levels).

The deployment of the FLEX strategies,. as described in the FIP, which is uhder review by the NRC staff and subject to subsequent inspection, is not affected by the impacts of the ISR flood :levels..

Associated effects and FED are reasonable and acceptable for use in the Wolf Creek MSA, and have been appropriately considered in the MSA..

Therefore, the NRC staff concludes that the licensee has followed the guidance *fn Appendix G of N:El *12-06, Revision 2, and demonstrated the capability to deploy the origin~! Fl.!.EX strategies, as designed, against a posftilated beyond-design-basis event for UP and upstream dam failure, including associated effects and flood event duration.

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Table 3.3. Flood Event Durations for Flood-Causing Mechanisms Not Bounded by the CD~

Flood.;Causing Time Available * ** Duration of Time for Water for PrE!pi;l,r~tic)h. Inundation qf to RecedE! from

Mechanism for Flood Event

.Site Site Local Intense Pr:ecipitation and Associated Dra,inage 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months 1.23 hours2.662037e-4 days 0.00639 hours 3.80291e-5 weeks 8.7515e-6 months 8.76 hours8.796296e-4 days 0.0211 hours 1.256614e-4 weeks 2.8918e-5 months

, Failure of Dams and Onsite Not Applicable Nqt Applicable Not Applicable Water Control/Storage Structures <1l Source: (Letters dated May 20, 2015, and November 8, 2016 (ADAMS Accession No. ML 15147A?16 and ML16321A424, respectively) a.n*d FHRR (ML16032A191})

Notes:

(1) The FED Qarameters for dam failure e:vent are not applicable due to a flood elevation margin of-OFFICIAL USE ONLY. SECURITY RELATED INFORMATION

OFFICIAL USE ONLY SEC~R~TY RELATED INFORMATION TABLE 3.4. ASSOCIATED EFFECTS PARAMETERS NOT DIRECTLY ASSOCIATED WITFI TOTAL WATER HEIGHT FOR FLOOD-CAUSING MECHANISMS NOT BOUNDED BY THE

, COB Associated Local Intense Failure of Dams and Onsite*

Effects Precipitation and Water Control/Storage Parameter Associated Drainage Structures <1>

Hydrodynamic 64 lb/ft for hydrostatic Not Applicable loading at plant 25 lb/ft. for hydrodynamic grade Debris loading at Minimal Not Applicable plant grade Sedim~nt loading-:-

Minimal Not Applicable at plant grade Sediment Minimal Not Applicable deposition and erosion Concurrent 38.65 Not Applicable conditions, including adverse weather - Winds Groundwater Minimal Not Applicable ingress Other pertinent Minimal Not Applicable factors (e.g.,

waterborne projectiles)

Source: (Letters dated M.aY 20, 2015, and November 8, 2016 (ADAMS Accession No. ML15147A516 and ML16321A424, respectively) and FHRR (ML16032A191))*

Notes:

(1) The \\ED ~s for dam failure event is not applicable due to a flood elevation mar.gino~

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Pkg. ML17033A334; (NON-PUBLIC) ML17033A126; (PUBLIC) ML17033A340

by e-mail dated OFFICE NRR/JLD/JHMB/PM NRR/JLD/l.A NRO/DSEAJRHM1* NRR/JLD/JERB/BC NR.R/JLD/JRMB/BC

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DATE 2/2117 212/17 1/10/17 2/10/17 2/16/17 NRR/JLD/JfiMB/PM LKGibson 3/15/17

v t e Letter Sequence Other
CAC:MF7992, (Open)
Initiation Acceptance... Administration Questions Answers Results Approval... Other: ML17033A340
MONTHYEAR2017-03-15 [Table View]

ML17033A340