RS-13-210, Supplemental Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding the Flooding Aspects of Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident

Supplemental Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding the Flooding Aspects of Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident

ML13241A288
Person / Time
Site:	Dresden
Issue date:	08/28/2013
From:	Kaegi G Exelon Generation Co
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
RS-13-210
Download: ML13241A288 (7)

Text

t Exelon Generation RS-13-210 10 CFR 50.54(f)

August28,2013 U.S. Nuclear Regulatory Commission Attn: Document Control Desk 11555 Rockville Pike, Rockville. MD 20852 Dresden Nuclear Power Station, Units 2 and 3 Renewed Facility Operating License Nos. DPR-19 and DPR-25 NRC Docket Nos. 50-237 and 50-249

Subject:

Supplemental Response to NRC Request for Information Pursuant to 10 CFR 50.54(f)

Regarding the Flooding Aspects of Recommendation 2.1 of the Near-Term Task Force Review of InSights from the Fukushima Dai-ichi Accident

References:

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

2. Exelon Generation Company, LLC letter to USNRC, Response to March 12, 2012, Request for Information Enclosure 2, Recommendation 2.1, Flooding, Required Response 2, Flooding Hazard Reevaluation Report, dated May 10, 2013 (RS-13-11 0)

On March 12, 2012, the NRC issued Reference 1 to all power reactor licensees and holders of construction permits in active or deferred status. Enclosure 2 of Reference 1 requested that each licensee perform a reevaluation of external flooding sources and report the results in accordance with the NRC's prioritization plan. Exelon Generation Company, LLC (EGC) submitted the flood reevaluation for Dresden Nuclear Power Station, Units 2 and 3 in Reference 2. Reference 2 contains interim actions that EGC has taken or plans to take to address higher flooding hazards relative to the design basis until the integrated assessment is completed .

The enclosed table provides a list of the interim actions taken or planned to be taken as contained in Reference 2 along with additional information and the dates by which they have or will be implemented.

These interim actions have been converted into commitments as requested by the NRC and are identified in the enclosed table. Also as requested by the NRC, EGC will not modify these commitments or completion dates without notifying the NRC in advance.

This letter contains new regulatory commitments as identified in the enclosed table.

Should you have any questions concerning the content of this letter, please contact Ron Gaston at (630) 657-3359.

U.S. Nuclear Regulatory Commission August 28, 2013 Page 2 I declare under penalty of perjury that the foregoing is true and correct. Executed on the 28thth day of August 2013.

Respectfully submitted,

~r¥ Glen T. Kaegi Director - Licensing & Regulatory Affairs Exelon Generation Company, LLC

Enclosure:

1. Dresden Nuclear Power Station, Units 2 and 3 - Flood Hazard Reevaluation Report Interim Action Commitments cc: Director, Office of Nuclear Reactor Regulation Regional Administrator - NRC Region III NRC Senior Resident Inspector - Dresden Nuclear Power Station NRC Project Manager, NRR - Dresden Nuclear Power Station Ms. Jessica A. Kratchman, NRR/JLD/PMB, NRC Mr. Eric E. Bowman, NRRlDPR/PGCB, NRC or Ms. Eileen M. McKenna, NRO/DSRAlBPTS, NRC Illinois Emergency Management Agency - Division of Nuclear Safety

Enclosure 1: Dresden Nuclear Power Station, Units 2 and 3 - Flood Hazard Reevaluation Report Interim Action Commitments* ("Commitments" are bolded header columns)

Item Interim Actions Taken or Implementation Commitment Commitment Number Planned to Take as Date Type Type Report Included in the Additional Information (Committed* One-Time Programmatic*

Reference Reevaluation Report Date or Action*

(Commitment*) Outage) (Yes/No) (Yes/No)

1. Enhanced river and rainfall Report Verified that procedure Completed Yes No forecasting information in Cover DOA 0010-04, FLOODS, January 25, flood emergency Letter, Rev. 35, contains 2013 procedures. Section enhanced river and d.ii rainfall forecasting information. The procedure includes detailed instructions for rain/flood forecasting using information available from National Weather Service and Army Corps of Engineers.

2. Installed markers at the Report Additional elevation Completed Yes No Dresden 2/3 cribhouse Cover markers have been January 25, between elevations 509 Letter, installed in 2/3 Reactor 2013 and 517 feet MSL, to Section Building Trackway. This support the enhanced river forecasting procedures. d.ii location will be used to place the Diesel Driven Emergency Makeup Pump on a floating platform in case of flood.

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Enclosure 1: Dresden Nuclear Power Station, Units 2 and 3 - Flood Hazard Reevaluation Report Interim Action Commitments* ("Commitments" are bolded header columns)

Item Interim Actions Taken or Implementation Commitment Commitment Number Planned to Take as Date Type Type Report Included in the Additional Information (Committed* One-Time Programmatic*

Reference Reevaluation Report Date or Action*

(Commitment*) Outage) (Yes/No) (Yes/No)

3. Installed permanent flood Report The flood panels have Completed Yes No barriers, in lieu of Cover been installed/staged. The January 25, sandbagging, to protect Letter, hardware and associated 2013 the isolation condenser Section tools and gaskets are makeup pump building.

d.ii staged in a dedicated tool box in the isolation condenser makeup pump building.

4. Purchased and mobilized Report Procedure DOA 0010-04, Completed Yes No floatable platform to raise Cover FLOODS, Rev. 39, January 25, the diesel driven pump as Letter, Attachment D, provides 2013 high as elevation 545 feet Section step by step instructions MSL (with the crane being the backup option); d.ii to place the diesel driven included in the latest pump on the floating update to flood emergency platform and make the procedure. necessary connections.

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Enclosure 1: Dresden Nuclear Power Station, Units 2 and 3 - Flood Hazard Reevaluation Report Interim Action Commitments* ("Commitments" are bolded header columns)

Item Interim Actions Taken or Implementation Commitment Commitment Number Planned to Take as Date Type Type Report Included in the Additional Information (Committed* One-Time Programmatic*

Reference Reevaluation Report Date or Action*

(Commitment*) Outage) (Yes/No) (Yes/No)

5. Modification plans are Report The design and March 31,2014 Yes No currently being evaluated Cover installation of the initial 11 to harden 11 penetrations Letter, flood barriers is complete.

around the reactor building Section The drop anchors have with passive flood d.ii been installed. The flood protection features to enhance current flood protection panels and the coping strategies. associated framework were installed to ensure proper fit. The panels were then removed and staged on carts nearby. I An additional penetration was identified and its barrier design is currently underway.

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Enclosure 1: Dresden Nuclear Power Station, Units 2 and 3 - Flood Hazard Reevaluation Report Interim Action Commitments* ("Commitments" are bolded header columns)

Item Implementation Commitment Commitment Interim Actions Taken or Number Planned to Take as Date Type Type Report Included in the Additional Information (Committed* One-Time Programmatic*

Reference Reevaluation Report Date or Action*

(Commitment*) Outage) (Yes/No) (Yes/No)

6. An evaluation of the Unit Report A Technical Evaluation of December 31, Yes No 2/3 Emergency Diesel Cover the roof has been 2013 Generator Building for Letter, performed. Its review and exposure to flooding is Section documentation is currently in progress to enhance current flood d.ii underway. A new roof was coping strategies. installed in 2009 and is found to be leak proof. A periodic maintenance (5 year interval) is part of ongoing surveillance program.

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Enclosure 1: Dresden Nuclear Power Station, Units 2 and 3 - Flood Hazard Reevaluation Report Interim Action Commitments* ("Commitments" are bolded header columns)

Item Interim Actions Taken or Implementation Commitment Commitment I Number Date Type Type Planned to Take as Report Included in the Additional Information (Committed* One-Time Programmatic*

Reference Reevaluation Report Date or Action*

(Commitment*) Outage) (VeS/No) (VeS/No)

7. Exelon has procured Report The vendor of the Aqua Completed Yes No approximately 4,000 feet of Cover Dam has performed a Aqua Dam material and Letter, simulation of its November 5, associated supplies to Section deployment. The results 2012 protect the power block d.ii are under review.

and the administration building to enhance current flood coping strategies.

The filled height of the Aqua Dam is a feet and the vendor's user guide recommends a flood protection heig ht of 6 feet with an a-foot high dam.

With a plant grade elevation of 517 feet MSL, the Aqua Dam will provide protection for floods up to elevation 523 feet MSL.

The Aqua Dam provides defense in depth while protecting the station assets for flood levels up to 523 feet MSL.

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