RS-13-079, Extension Request - Response to March 12, 2012, Request for Information Enclosure 2, Recommendation 2.1, Flooding, Required Response 2, Flooding Hazard Reevaluation Report

Extension Request - Response to March 12, 2012, Request for Information Enclosure 2, Recommendation 2.1, Flooding, Required Response 2, Flooding Hazard Reevaluation Report

ML13071A314
Person / Time
Site:	Dresden
Issue date:	03/11/2013
From:	Kaegi G Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
RS-13-079
Download: ML13071A314 (5)

Text

1 Exelon Generation 10 CFR 50.54(f) 10 RS-1 3-079 March 11, 2013 March U.S. Nuclear Nuclear Regulatory Regulatory Commission Commission ATTN: Document Control Desk Desk Washington, DC Washington, DC 20555 20555 Dresden Nuclear Power Station, Dresden Station, Units 2 and 33 Renewed Facility Operating Renewed Operating License Nos. DPR-19 and DPR-25 NRC Docket Nos. 50-237 and and 50-249 50-249

Subject:

Extension Request -- Response Extension Responseto toMarch March 12,12,2012, 2012, Request Requestfor forInformation Information Enclosure 2, Enclosure 2, Recommendation 2.1, Flooding,Flooding, Required ResponseResponse2,2,Flooding Flooding Hazard Reevaluation Report Report

References:

1. NRC NRC Letter, Letter, Request Information Pursuant Request for Information Pursuant to Title 10 of the Code Code of of Federal Federal 50.54(f) Regarding Regulations 50.54(f) Regarding Recommendations 2.1, 2.3, and 2.1,2.3, and 9.3, 9.3, ofof the the Near-Term Near-Term Force Review Task Force Review of of Insights Insights from from the Fukushima FukushimaDai-ichi Dai-ichi Accident, dated dated March March 12, 12, 2012

2. NRC NRC Letter, Letter, Prioritization PrioritizationofofResponse Response Due DatesDates for for Request Requestfor forInformation Information Pursuant Pursuant to Title Title 10 10 of of the the Code Code of of Federal Regulations 50.54(f) 50.54(f) Regarding Flooding Flooding Hazard Hazard Reevaluations for Recommendations Recommendations 2.1 2.1 of of the the Near-Term Near-Term Task TaskForce ForceReview Reviewof of Insights From the Fukushima Dai-ichi Accident, Fukushima Dai-ichi Accident, dated May May 11, 2012 2012

3. NRC NRC Letter, Letter, Supplemental Information Related to Request Supplemental Information Requestfor for Information Information Pursuant Pursuanttoto Title 10 of Title 10 of the the Code Code ofof Federal Regulations 50.54(f) 50.54(f) Regarding Flooding Flooding HazardHazard Reevaluations for Recommendation 2.1 2.1 of of the the Near-Term Near-Term Task Task Force ForceReview Reviewof of Insights Insights from from the Fukushima Fukushima Dai-Ichi Accident, dated Dai-Ichi Accident, dated March 1, 2013 2013

4. Letter fromfrom Exelon Exelon Generation Company, LLC (EGC), to U.S. Nuclear Nuclear Regulatory Regulatory Commission, "180-day Response to NRC Request Request for Information Information Pursuant to Pursuant to 10 10 CFR CFR 50.54(f) Regarding the Flooding Aspects of RecommendationRecommendation 2.3 2.3 ofof the the Near-Term Near-Term Task Task Force Review of Insights from the Fukushima Dai-ichi Accident", dated November November 27, 27, 2012 (RS-12-168)

On March March 12,12, 2012, the NRC NRC issued issued Reference Reference11totorequest requestinformation information associated associatedwith withNear-Near-Term Task Task Force (NTTF) Recommendation 2.1 for Flooding.

2.1 for One of Flooding. One of the the required required responses responses in in this letter directed licensees letter directed licenseestotosubmit submitaaHazard HazardReevaluation ReevaluationReport, Report,including includingthe theinterim interim plan requested in Item action plan Item 1.d of Reference 1, 1, Enclosure Enclosure 2, 2, ifif appropriate.

appropriate. On On MayMay 11,11, 2012, 2012, the NRC NRC issued issuedthetheprioritization plan developed prioritization plan developed by bythe theNRC NRCand andresultant resultantFlooding FloodingHazard Hazard

U.S. Nuclear Regulatory Commission U.S.

Flood Hazard Flood Hazard Reevaluation Report March 11, March 2013 11,2013 Page 2 Reevaluation due Reevaluation due dates for all all sites.

sites. Reference Reference2,2,Enclosure Enclosure11identified identified the Dresden Dresden NuclearNuclear Station, Units Power Station, Units 22 and and 3 (DNPS)

(DNPS) site site as aa Category Category 11 Site Site requiring requiring a Flooding Flooding Hazard Reevaluation Report submittal due date date of of March March 12, 12, 2013.

2013.

The purpose of of this letter is to to request an an extension extension to to the the scheduled scheduledsubmittal submittaldate datefor forthe the DNPS Flooding DNPS Flooding Hazard Hazard Reevaluation Report to May May 10, 2013. EGC EGCisisperforming performing aadetaileddetailed2D 2D model of model of the the flooding flooding hazard hazard forfor the the DNPS DNPS site, site, and additional time is required to complete the DNPS 2D DNPS 2D model, model, and the verification verification and and validation validation of of the the calculation calculation assumptions, assumptions, input input data, and results. This This request requestforforextension extensionaddresses addressesthe theNRCNRCstaffstaffpositions positionsprovided providedin in Reference 3.

This extension request is justified on the following basis: basis:

• As recognized in the NRC's March As March 2012 50.54(f) 50.54(f) letter, the current regulatory approach approach and the the resultant resultant plant plant capabilities capabilities provide provide confidence confidence that thatan anaccident accidentwith with consequences similar consequences similarto tothe theFukushima Fukushimaaccidentaccidentisisunlikely unlikelyto tooccur occurininthetheUnited United States, andand that continued plant operation does not pose an imminent risk topublic that continued plant operation does not pose an imminent risk to public health and safety. Therefore, Therefore, the theduration duration of of this extension requestrequest hashasno noimpact impact on on safe plant operation.

• The DNPS DNPS recently recently completed completedwalkdownswalkdownswhich whichverified verifieditsitscurrent currentflooding floodinglicensing licensing basis (Reference (Reference 4). 4). The TheDNPSDNPScurrentcurrentlicensing licensing basis basisisisbeing being met.

met. Therefore, Therefore,DNPS DNPS is protected from from current current design design basis flood events.

• The events events being being analyzed analyzed in in the the DNPS DNPS Flooding Flooding Hazard Hazard Reevaluation Reevaluation are are beyond beyondthe the plant's design and licensing licensing basis. Therefore, Therefore, the the reevaluation reevaluation results based based on on beyond design basis basis events events do donotnot constitute constitute an an operability operability concern. This This isis consistent consistent with the with the NRC NRC supplemental supplemental information letter dated information letter dated March March 1,2013 1, 2013 (Reference 3). 3).

• The reevaluated reevaluated flooding flooding hazard hazard(Probable (ProbableMaximum MaximumFlood Flood(PMF))

(PMF)) isisaavery verylow low probabilityevent, probability event, and and the the time time frame frame represented represented by the extension request request would would resultresult in an insignificant in contribution to insignificant contribution to the the overall overall risk.

risk. The PMFPMF event event at at DNPS DNPSisis considered to have have aavery very lowlow likelihood likelihood of of occurrence.

occurrence. The water water surface surface elevation elevation (WSE) was (WSE) was estimated to to be be below below 513 513 ft.

ft. with with a return period of 1000 years, which which demonstrates demonstrates considerable considerablemargin marginfrom from the the plant plant grade gradeof of 517 517 ft.

ft. and and even even moremorefrom from the design design basis basisPMFPMF WSE WSE of of 528 528 ftft (with wind-generated waves).

(with wind-generated waves). The The data dataisis consistent consistent with with a recent recent Army Army Corps of of Engineers Engineers (ALOE)(ACOE) study that supports supports the the conclusion that the frequency frequency of of occurrence occurrence of of the the PMF PMF at at the the DNPS DNPS site siteisisvery verylow.low.

Furthermore, the frequency estimates Furthermore, estimates used usedin in this this ACOE ACOE analysis were were expressed expressedinin terms of of `annual

'annual exceedance exceedanceprobability'.

probability'. While historical records While historical records indicate that instantaneous instantaneous annual annual peak peakflowsflows frequently frequently occur in in the spring months, annual peaks peaks from the summer and early from the early fall months are also included fall months included in the estimate. This Thiswouldwould result in the exceedance in the exceedance probability probability for for the the requested extension extension period period being being eveneven lessless when compared to the annual exceedance. exceedance.

U.S. Nuclear Regulatory Commission Commission Flood Hazard Reevaluation Report Flood Report March 11, 2013 11,2013 Page 3

• The following floodhazard following flood hazardmitigation mitigationinterim interimactions actionshave havebeen been taken taken at the DNPS site beyond those required by the current design basis:

Enhanced river river and and rainfall rainfall forecasting information information in flood flood emergency emergency procedures Installed river level markers to support enhancements to procedures Installed permanent floodflood barriers to protect the isolation condenser condenser makeup makeup pump building Mobilized floatable Mobilized floatable platform platform to to raise raise diesel driven driven pump pump Acquired Aqua Dam (portable dam) to protect Acquired protect power power block block toto elevation elevation 523 523ft.

ft.

MSL These actions These actionsprovide provideaasufficient sufficientlevel level of of flood flood hazard hazard protection protectionfor for the theperiod periodofofthe the extension request. No Noadditional additionalflood flood hazard hazard mitigation mitigation or protection actions beyond those identified those identified above are warranted for for the period of the extension request. request.

Based on the above determinations, determinations, EGCEGC has has concluded concluded that that the the requested requestedextension extensiontotothethe scheduled submittal date for submittal date for the DNPS Flooding ON PS Flooding Hazard Reevaluation Report does not impact does not impact safe plant plant operation or represent represent an an undue undueriskrisktoto public public health health and and safety.

safety.Accordingly, Accordingly, EGC EGC requests NRC requests NRC approval to extend the the scheduled scheduledsubmittal submittal datedatefor for the theDNPS DNPS Flooding Flooding Hazard Hazard Reevaluation Report to to May May 10, 2013.

2013.

A list of regulatory commitments contained in this letter is provided in A in Enclosure Enclosure 1. 1.

If you regarding this you have any questions regarding this submittal, submittal, please please contact Ron Gaston at contact Ron (630) 657-3359.

II declare declare under penalty penalty of of perjury perjury that the foregoing foregoing is is true true and andcorrect.

correct.Executed Executedon onthe the11th 11 th day of March 2013.

Respectfully submitted, Glen T. Kaegi Director -- Licensing & Regulatory Director Regul* tory Affairs Exelon Generation Company, Company, LLC LLC

Enclosure:

1. Summary of Regulatory Commitments Commitments

U.S. Nuclear Regulatory Regulatory Commission Commission Flood Hazard Reevaluation Report Flood March 11, March 2013 11,2013 Page 4 cc: Director, Office Director, Officeof of Nuclear Nuclear Reactor Reactor Regulation Regional Administrator Administrator -- NRC NRC Region RegionIII III NRC Senior NRC Senior Resident Inspector - Dresden DresdenNuclear NuclearPower PowerStation Station NRC Project NRC Project Manager, NRR - Dresden Nuclear Nuclear Power Power Station Station Ms. Jessica Ms. Jessica A.

A. Kratchman, Kratchman,NRR/JLD/PMB, NRR/JLD/PMB, NRCNRC Mr. Eric Mr. Eric E.

E. Bowman, NRR/DPR/PGCB, NRC NRC or or Ms.

Ms. Eileen Eileen M.

M. McKenna, McKenna, NRO/DSRAlBPTS, NRO/DSRA/BPTS, NRC NRC Illinois Emergency Illinois Emergency Management Management Agency Agency --Division Division of Nuclear Safety Safety

U.S. Nuclear Regulatory Commission U.S.

Flood Hazard Flood Hazard Reevaluation Reevaluation Report March 11,2013 March 11, 2013 Page 11 Enclosure 11 Enclosure REGULATORY COMMITMENTS

SUMMARY

OF REGULATORY COMMITMENTS The following table identifies following table identifiescommitments commitmentsmademade ininthis thisdocument.

document. (Any (Any other actions discussed discussed in in the the submittal submittal represent represent intended intended oror planned planned actions. They are actions. They are described described to to the the NRC NRC for for the NRC's information information and are are not not regulatory regulatory commitments.)

commitments.)

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

Dresden Nuclear Nuclear Power Power Station, Units Units 2 and May May 10, 2013 Yes No 3 will submit the Flooding Hazard Reevaluation Report, including interim action plan, requested in Item 1.d of Enclosure Enclosure 2 of NRC Letter, Request Request for Information Information Pursuant to Title 1010 of of the Code Code ofof Federal Federal Regulations 50.54(f) Regarding Regarding Recommendations 2.1, 2.3, and 9.3, of the Near-Term Task Force Review of Insights Insights from the Fukushima Fukushima Dai-ichi Dai-ichi Accident, Accident, dated dated March 12, 2012.