ML14241A432
| ML14241A432 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 08/14/2014 |
| From: | Hamrick G T Duke Energy Carolinas |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| BSEP 14-0087 | |
| Download: ML14241A432 (7) | |
Text
George T. HamrickVice PresidentENERGY, Brunswick Nuclear PlantP.O. Box 10429Southport, NC 28461o: 910.457.369810 CFR 50.54(f)August 14, 2014Serial: BSEP 14-0087U. S. Nuclear Regulatory CommissionATTN: Document Control DeskWashington, DC 20555-0001
Subject:
Brunswick Steam Electric Plant, Unit Nos. 1 and 2Docket Nos. 50-325 and 50-324Renewed License Nos. DPR-71 and DPR-62Response to Request for Additional Information Associated with Near-Term TaskForce Recommendation 2.1, Seismic Hazard and Screening Report
References:
- 1. NRC Letter, Request for Information Pursuant to Title 10 of the Code of FederalRegulations 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, datedMarch 12, 2012, ADAMS Accession No. ML12053A340.2. Electric Power Research Institute (EPRI) Report 1025287, Seismic EvaluationGuidance, Screening, Prioritization and Implementation Details (SPID) for theResolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic,dated November 2012, ADAMS Accession No. ML12333A1 70.3. NRC Letter, Endorsement of EPRI Final Draft Report 1025287: "Seismic EvaluationGuidance," dated February 15, 2013, ADAMS Accession No. ML12319A074.4. Duke Energy Letter, Seismic Hazard and Screening Report (CEUS Sites), Responseto NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding the SeismicAspects of Recommendation 2. 1 of the Near-Term Task Force Review of Insightsfrom the Fukushimd Dai-ichi Accident, dated March 31, 2014, ADAMS Accession No.ML14106A461.5. NRC Letter, Brunswick Steam Electric Plant, Units 1 and 2 -Request for AdditionalInformation Associated with Near-Term Task Force Recommendation 2. 1, SeismicHazard and Screening Report, dated July 16, 2014, ADAMS Accession No.ML14195A071.oC U.S. Nuclear Regulatory CommissionPage 2 of 3Ladies and Gentlemen,On March 12, 2012, the U. S. Nuclear Regulatory Commission (NRC) staff issued a letterrequesting information per Title 10 of the Code of Federal Regulations, Section 50.54(f)(i.e., Reference 1). The letter requested licensees located in the Central and Eastern UnitedStates (CEUS) to submit a Seismic Hazard Evaluation and Screening Report. Reference 2contains industry guidance and detailed information to be included in the Seismic HazardEvaluation and Screening Report submittals. The industry guidance was endorsed by theNRC in Reference 3.By letter dated March 31, 2014 (i.e., Reference 4), Duke Energy submitted to the NRC theSeismic Hazard and Screening Report. By letter dated July 16, 2014 (i.e., Reference 5), theNRC requested additional information related to the Individual Plant Examination forExternal Events (IPEEE) for Brunswick Steam Electric Plant (BSEP), Units 1 and 2. TheNRC staff requested that a response be provided no later than August 15, 2014, asdiscussed during a recent phone call with members of my staff.Enclosed, please find the response to the request for additional information.This letter contains no new regulatory commitments.If you have any questions regarding this submittal, please contact Mr. Lee Grzeck,Manager-Regulatory Affairs, at (910) 457-2487.I declare under penalty of perjury that the foregoing is true and correct, executed onAugust 14, 2014.Sincerely,C4~ a j~,muGeorge T. HamrickRAZ/raz
Enclosure:
Response to the NRC Request for Additional Information (RAI) Associated withNear-Term Task Force Recommendation 2.1, Seismic Hazard and ScreeningReport U.S. Nuclear Regulatory CommissionPage 3 of 3cc (with enclosures):U. S. Nuclear Regulatory Commission, Region IIATTN: Mr. Victor M. McCree, Regional Administrator245 Peachtree Center Ave, NE, Suite 1200Atlanta, GA 30303-1257U. S. Nuclear Regulatory CommissionATTN: Ms. Michelle P. Catts, NRC Senior Resident Inspector8470 River RoadSouthport, NC 28461-8869U. S. Nuclear Regulatory CommissionATTN: Mr. Andrew Hon (Mail Stop OWFN 8G9A) (Electronic Copy Only)11555 Rockville PikeRockville, MD 20852-2738Chair -North Carolina Utilities CommissionP.O. Box 29510Raleigh, NC 27626-0510 BSEP 14-0087EnclosurePage 1 of 4Response to NRC Request for Additional Information (RAI) Associated With Near-TermTask Force Recommendation 2.1. Seismic Hazard and Screening Report
Background:
On March 12, 2012, the NRC issued a request for information pursuant to 10 CFR 50.54(f) togather information concerning, in part, the seismic hazards at operating reactor sites and toenable the NRC staff to determine whether licenses should be modified, suspended, or revoked.In response to the 50.54(f) letter, Duke Energy committed to follow the Electric Power ResearchInstitute (EPRI) Report, "Seismic Evaluation Guidance: Screening, Prioritization andImplementation Details (SPID) for the Resolution of Fukushima Near-Term Task ForceRecommendation 2.1: Seismic," (ADAMS Accession No. ML12333A170) as supplemented bythe EPRI Report, "Seismic Evaluation Guidance: Augmented Approach for the Resolution ofFukushima Near-Term Task Force (NTTF) Recommendation 2.1: Seismic" (ADAMS AccessionNo. ML13102A142). The reevaluation of the seismic hazards for Brunswick Steam ElectricPlant (BSEP), Units 1 and 2, was submitted to the NRC by letter dated March 31, 2014 (ADAMSAccession No. ML 14106A461). On May 9, 2014, the NRC staff issued a letter (ADAMSAccession No. ML 14111 Al 47) identifying BSEP, Units 1 and 2, as "conditional screen-in" forthe purposes of prioritizing and conducting additional evaluations.In accordance with the SPID and Augmented Approach guidance, the reevaluated seismichazard is used to determine if additional seismic risk evaluations are warranted. The SPIDguidance provides criteria for a plant with ground motion response spectra (GMRS) above thesafe shutdown earthquake, but bounded by the Individual Plant Examination for External Events(IPEEE) capacity spectrum. A plant screens out of conducting a seismic risk evaluation if theIPEEE capacity is greater than the GMRS in the 1-10 Hz range. The March 31, 2014, submittaldemonstrates the adequacy of the IPEEE seismic evaluation and provides full-scope soil failureevaluation results.By letter dated July 16, 2014 (ADAMS Accession No. ML14195A071), the NRC requestedadditional information related to the IPEEE for BSEP, Units 1 and 2. The NRC staff requestedthat a response be provided no later than August 15, 2014, as discussed during a recent phonecall with BSEP staff.NRC RAI 1:In Appendix B, Section 2.1.2 of the submittal, it states that soils evaluation considered relevantstructures on the Safe Shutdown Equipment List which includes the intake canal. The submittalalso states that slope stability screens out at BSEP. Describe the basis for screening out slopestability along the intake canal under the review level earthquake loading.
BSEP 14-0087EnclosurePage 2 of 4BSEP Response to RAI 1:The Intake Canal was originally designed to provide normal cooling water loads for five (5) units.The current design accommodates a flow requirement of 1390 cubic feet (ft3)/ second per unit.The maximum designed capacity of the Intake Canal is approximately 7,000 ft3/second. TheIntake Canal mean sea level (MSL) velocity for one unit operating is 0.3 feet (ft)/second, andmaximum low tide velocity is 0.4 ft/second. When two units are in operation the MSL velocity is0.6 ft/second, and maximum low tide velocity is 0.8 ft/second. The representative low waterlevel velocity in the Intake Canal is 1.5 ft/second.The bottom of the Intake Canal is at Elevation -18 feet MSL; The Intake Canal bottom is 170feet wide, and the side slopes are at a 4Horizontal (H):1 Vertical (V) slope in the marsh area,and 3H:1V in the high ground area. The total length of the Intake Canal is 2.57 miles. Thefigure below provides a cross-sectional profile of the Intake Canal.High Ground Area Intake Canal Cross-Section ProfileUINTAKE CANAL.SERVICE ROAD..SERVICE ROADIEL. 36'The original Intake Canal design evaluation acknowledges that the Intake Canal is susceptibleto slope sliding as discussed in the original Final Safety Analysis Report (FSAR). Section2.4.8.2 of the current Updated FSAR provides a general description of the Intake Canal.A breakdown of the consequences of liquefaction based on soil conditions and topography isprovided in EPRI Report NP-6041-SL, Table 7-1A, "Relationship Between Observed LateralDeformation During Earthquakes and Geometric Properties of Liquefied Alluvial Soils". Intake BSEP 14-0087EnclosurePage 3 of 4Canal slope slides similar to those presented in Table 7-1A will occur based on the canal designslope, elevation changes and susceptibility to liquefaction.To illustrate the margin associated with the Intake Canal, sliding at any point along the IntakeCanal length, on both sides, is conservatively postulated to occur. For the purpose ofdetermining the adequacy of the IPEEE for BSEP, Units 1 and 2, complete failure of canalslopes with all soils sliding into canal is assumed. This results in a median angle of repose ofapproximately 50 corresponding to a slope of approximately 12H:1V. The amount of materialtransported will not significantly impact the Intake Canal performance.The Service Water system provides all critical cooling water needs for normal and emergencyplant conditions. Service Water pump capacity for all ten (10) pumps for both units is 80,000gallons per minute (gpm). At a velocity of 1.5 ft/second, the required cross-section area for80,000 gpm is 119 square feet (ft2). Design cross-section area of the canal at low tide is3,760 ft2.After postulated worst case canal slope failure the remaining cross-section area ofwater would be at least 910 ft2.This is more than seven times the maximum demand of all 10Service Water pumps. For this worst case scenario, the Intake Canal design capacity ensuressignificant margin remains to provide adequate cooling water to both units following a ReviewLevel Earthquake (RLE) of 0.3g.Simplistic & Conservative Intake Canal Profile After Slope FailureEL 0' E .-- , .I \-A=910 Ft2A monitoring program is in place to perform hydrographic surveys of cross-sections along thelength of the Intake Canal at various stations and is used to determine when canal dredging isrequired to maintain the Intake Canal profile. Intake Canal maintenance dredging is performedin accordance with a recurring Preventive Maintenance (PM) program Work Order model. Postdredging hydrographic surveys are performed to ensure acceptable Intake Canal profiles areachieved.
BSEP 14-0087EnclosurePage 4 of 4NRC RAI 2:In Appendix B, Section 2.1.2 of the submittal, it states that considerations similar to Table 7-1Aof Reference 6.4 was used for screening out liquefaction for the intake canal. If appears that thereference should have been Reference 6.6. Clarify whether the submittal should cite Reference6.6 instead of Reference 6.4 when referring to Table 7-1A or provide a description of theconsiderations were used for screening.BSEP Response to RAI 2:The submittal should have cited Reference 6.6 instead of Reference 6.4 when referring to Table7-1A.