RS-14-056, Extension Request - Response to March 12, 2012 Request for Information on Enclosure 2, Recommendation 2.1, Flooding, Required Response 2, Flood Hazard Reevaluation Report
| ML14071A278 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 03/12/2014 |
| From: | David Helker Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| RS-14-056 | |
| Download: ML14071A278 (6) | |
Text
RS-14-056 March 12,2014 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 Peach Bottom Atomic Power Station, Units 2 and 3 Renewed Facility Operating License Nos. DPR-44 and DPR-56 NRC Docket Nos. 50-277 and 50-278 10 CFR 50.54{f)
Subject:
Extension Request - Response to March 12, 2012, Request for Information, Recommendation 2.1, Flooding, Required Response 2, Flood Hazard Reevaluation Report
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. NRC Letter, Prioritization of Response Due Dates for Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Flooding Hazard Reevaluations for Recommendation 2.1 of the Near-Term Task Force Review of Insights From the Fukushima Dai-ichi Accident, dated May 11, 2012
- 3. Letter from Exelon Generation Company, LLC (EGG), to U.S. Nuclear Regulatory Commission, 90-Day Response to March 12,2012 Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendations 2.1 and 2.3, of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident (Flooding), dated June 11, 2012
- 4. NRC Letter, Supplemental Information Related to Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Flooding Hazard Reevaluations for Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident, dated March 1, 2013
- 5. Letter from Exelon Generation Company, LLC (EGC), to U.S. Nuclear Regulatory Commission, 180-day Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding the Flooding Aspects of Recommendation 2.3 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident, dated November 19, 2012 (RS-12-174)
- 6. NRC, Interim Staff Guidance, Guidance for Assessment of Flooding Hazards Due to Dam Failure, JLD-ISG-2013-01, Revision 0, dated July 29, 2013
U.S. Nuclear Regulatory Commission Peach Bottom Flood Hazard Reevaluation Report March 12, 2014 Page 2
- 7. Letter from Exelon Generation Company, LLC (EGC), to U.S. Nuclear Regulatory Commission, "Assistance in Obtaining Information on Dams, Peach Bottom Atomic Power Station - Units 2 and 3, NRC Docket Nos. 50-277 and 50-278, Facility Operating License Nos. DPR-44 and DPR-56", dated November 22,2013
- 8. U.S. Nuclear Regulatory Commission, NUREG/CR-7046, "Design-Basis Flood Estimation for Site Characterization at Nuclear Power Plants in the United States of America", dated November 2011.
On March 12, 2012, the NRC issued Reference 1 to request information associated with Near-Term Task Force (NTTF) Recommendation 2.1 for Flooding. One of the required responses in this letter directed licensees to submit a Hazard Reevaluation Report, including the interim action plan requested in Item 1.d of Reference 1, Enclosure 2, if appropriate. On May 11, 2012, the NRC issued the prioritization plan developed by the NRC and resultant Flooding Hazard Reevaluation due dates for all sites. Reference 2, Enclosure 1 identified the Peach Bottom Atomic Power Station, Units 2 and 3 (PBAPS) site as a Category 2 Site requiring a Flooding Hazard Reevaluation Report submittal due date of March 12, 2014. In Reference 3, EGG indicated that it planned to comply with the requested response dates.
The purpose of this letter is to request an extension to the scheduled submittal date for the PBAPS Flooding Hazard Reevaluation Report. In Reference 4, the NRG states "an extension request should include: 1) the reason for the delay; 2} a proposed schedule for the submittal of a complete Hazard Reevaluation Report; and 3) the basis for the acceptability of the revised schedule." These items are addressed below.
This letter also serves as notification that EGG is withdrawing the request for assistance in obtaining upstream dam information from the US Army Gorps of Engineers (USAGE)
(Reference 7). EGG is currently assuming upstream dams fail under hydrologic and seismic loading conditions and believes previously-obtained information will be sufficient in.developing the models. Therefore, USAGE participation in the flood hazard reevaluation process is not addressed in the items discussed below.
- 1. Reason for the Delay - EGG is developing a detailed hydrologic model of the Susquehanna River watershed for the flooding hazard for the PBAPS site. Additional time is required to complete the model and verify and validate the calculation assumptions, input data, and results. In particular, the request to extend the reevaluation schedule is intended to accommodate the following:
A detailed hydrometerological study that will produce new extreme rainfall and snowmelt parameters specific to the Susquehanna River watershed.
Provisions specified in the NRG's Interim Staff Guidance for the Assessment of Flooding Hazards Due to Dam Failure (Reference 6).
The latest USAGE's National Inventory of Dams database, updated in May 2013.
Being in the same watershed, EGG's objective is to establish consistency in the hydrologic model that forms the bases for the PBAPS and Three Mile Island
U.S. Nuclear Regulatory Commission Peach Bottom Flood Hazard Reevaluation Report March 12, 2014 Page 3 (TMI) flood hazard reevaluations. The TMI Flood Hazard Reevaluation Report was submitted to the NRC on March 12,2013. EGC anticipated receiving feedback from the NRC on the TMI submittal in such a time that would allow applicable comments/ issues to be incorporated into the PBAPS reevaluation.
- 2. Proposed schedule for the submittal of a complete Flood Hazard Reevaluation Report - EGC is proposing to complete and submit the Flood Hazard Reevaluation Report on March 12, 2015, with interim milestones listed below.
May 21, 2014 - Complete calibration of the hydrologic model of the Susquehanna River Watershed.
July 24, 2014 - Complete development of the Probable Maximum Flood (PMF) and upstream dam failure hydrographs.
December 24, 2014 - Complete calculations of flood level and associated effects at the PBAPS for the applicable combined-effect floods in Appendix H of Reference 8.
March 12,2015 - Submit Flood Hazard Reevaluation package to the NRC.
- 3. Basis for the acceptability of the revised schedule As recognized in the NRC's March 12, 2012 50.54(f) letter, the current regulatory approach and resultant plant capabilities provide confidence that an accident with consequences similar to the Fukushima accident is unlikely to occur in the United States, and that continued plant operation does not pose an imminent risk to public health and safety. Therefore, the duration of this extension request has no impact on safe plant operation.
The PBAPS recently performed walkdowns that verified its current flooding licensing basis (Reference 5). During the walkdowns, all features were determined to be acceptable or deficiencies were entered into the corrective action program and determined to be operable. Therefore, PBAPS is protected from current design basis flood events.
The events being analyzed in the PBAPS Flooding Hazard Reevaluation are beyond the plant's design and licensing basis. Therefore, the reevaluation results based on beyond design basis events do not constitute an operability concern. This is consistent with the NRC supplemental information letter dated March 1, 2013 (Reference 4).
The reevaluated flooding hazard (Probable Maximum Flood (PMF>> is a very low probability event, and the time frame represented by the extension request would result in an inSignificant contribution to the overall risk. The normal elevation of Conowingo Pond is between 104 feet to 109.25 feet (all elevations are Conowingo Datum, which is 0.7 feet above Mean Sea Level). During the record flood of 1972, the water level rose to 113.5 feet, exclusive of wave run-up. The
U.S. Nuclear Regulatory Commission Peach Bottom Flood Hazard Reevaluation Report March 12,2014 Page 4 current licensing basis PMF produces maximum still water elevation of 131.5 feet, plus a flood-wave of 0.5 foot for a postulated upstream dam failure which results in a maximum elevation of 132.0 feet. PBAPS structures required for safe shutdown are flood protected to elevation 135 feet, which demonstrates considerable margin above the worst historic event and design basis PMF.
As a result of operating procedure simulations, PBAPS revised Special Event Flood Procedure (SE-4) and the System Operating Procedure for Emergency Cooling Water System Startup (SO 48.1.B). Changes were made to the sequence of steps only, which resulted in a reduction in the time required for operators to take flood mitigation actions.
As a result of review of Available Physical Margin, PBAPS revised Special Event Flood Procedure (SE-4) to add sandbags at the Emergency Cooling Tower Door.
This is an interim mitigating action for protection against the maximum wind-generated waves.
These actions provide a sufficient level of flood hazard protection for the period of the extension request. No additional flood hazard mitigation or protection actions beyond those identified above are warranted for the period of the extension request.
Based on the above determinations, EGC has concluded that the requested extension to the scheduled submittal date for the PBAPS Flooding Hazard Reevaluation Report does not impact safe plant operation or represent an undue risk to public health and safety. Accordingly, EGC requests NRC approval to extend the scheduled submittal date for the PBAPS Flooding Hazard Reevaluation Report to March 12, 2015.
A list of regulatory commitments contained in this letter is provided in Enclosure 1.
If you have any questions regarding this submittal, please contact Ron Gaston at (630) 657-3359.
I declare under penalty of perjury that the foregoing is true and correct. Executed on the 12th day of March 2014.
Respectfully submitted, David P. Helker Manager - Licensing & Regulatory Affairs Exelon Generation Company, LLC
Enclosure:
- 1.
Summary of Regulatory Commitments
U.S. Nuclear Regulatory Commission Peach Bottom Flood Hazard Reevaluation Report March 12, 2014 Page 5 cc:
Director, Office of Nuclear Reactor Regulation Regional Administrator - NRC Region I NRC Senior Resident Inspector -- Peach Bottom Atomic Power Station NRC Project Manager, NRR -- Peach Bottom Atomic Power Station Mr. G. Edward Miller, NRR/DORULPL2-1, NRC Director, Bureau of Radiation Protection -- Pennsylvania Department of Environmental Resources S. T. Gray, State of Maryland R. R. Janati, Chief, Division of Nuclear Safety, Pennsylvania Department of Environmental Protection, Bureau of Radiation Protection
U.S. Nuclear Regulatory Commission Flood Hazard Reevaluation Report March 12, 2014 Page 1 ENCLOSURE 1
SUMMARY
OF REGULATORY COMMITMENTS The following table identifies commitments made in this document. (Any other actions discussed in the submittal represent intended or planned actions. They are described to the NRC for the NRC's information and are not regulatory commitments.)
COMMITTED COMMITMENT TYPE COMMITMENT DATE OR ONE-TIME ACTION PROGRAMMATIC "OUTAGE" (YesINo)
(YesINo)
Peach Bottom Atomic Power Station, Units 2 March 12, 2015 Yes No and 3 will submit the Flooding Hazard Reevaluation Report, including interim action plan, requested in Item 1.d of Enclosure 2 of 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.