ML14195A086
| ML14195A086 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 07/16/2014 |
| From: | Michael Balazik Japan Lessons-Learned Division |
| To: | Cortopassi L Omaha Public Power District |
| Balazik M, NRR/JLD, 415-2856 | |
| References | |
| Download: ML14195A086 (4) | |
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Mr. Louis Cortopassi Site Vice President and Chief Nuclear Officer Omaha Public Power District Fort Calhoun Station Mail Stop FC-2-4 9610 Power Lane Blair, NE 68008 WASHINGTON, D.C. 20555-0001 July 16, 2014
SUBJECT:
FORT CALHOUN STATION, UNIT 1 -REQUEST FOR ADDITIONAL INFORMATION ASSOCIATED WITH NEAR-TERM TASK FORCE RECOMMENDATION 2.1, SEISMIC HAZARD AND SCREENING REPORT
Dear Mr. Cortopassi:
By letter dated March 31, 2014, to the Nuclear Regulatory Commission (NRC) (Agencywide Documents and Management System (ADAMS) Accession No. ML14097A087), Omaha Public Power District (OPPD), submitted for NRC review the OPPD Seismic Hazard and Screening Report, Response NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident for Fort Calhoun Station (FCS), Unit 1.
The NRC staff has reviewed the information provided for FCS and has determined that additional information is required to complete the review. Enclosed is a request for additional information (RAI) related to the plant's Individual Plant Examination for External Events. As discussed with your staff during a recent phone call, the NRC staff requests that you respond no later than August 15, 2014.
If you have any questions related to the enclosed RAisor the requested submission date, please contact me at 301-415-2856 or via e-mail at michael.balazik@nrc.gov.
Docket No. 50-285
Enclosure:
Request for Additional Information cc w/encl: Distribution via Listserv Sincerely, 1-v11 J; rttVi MichaeWa'zik, Project Ma ager Hazards Management Bra ch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation
REQUEST FOR ADDITIONAL INFORMATION NEAR-TERM TASK FORCE RECOMMENDATION 2.1, SEISMIC HAZARD AND SCREENING REPORT OMAHA PUBLIC POWER DISTRICT FORT CALHOUN STATION, UNIT 1 DOCKET NO. 50-285 On March 12, 2012, the U.S. Nuclear Regulatory Commission (NRC) issued a request for information pursuant to Title 10 of the Code of Federal Regulations, Part 50 (1 0 CFR),
Section 50.54(f) (hereafter referred to as the 50.54 (f) letter) (Agencywide Documents Access and Management System (ADAMS) Accession No. ML12053A340). The purpose of the request was to gather information concerning, in part, the seismic hazards at operating reactor sites and to enable the NRC staff to determine whether licenses should be modified, suspended, or revoked. To respond to the 50.54(f) letter, Omaha Public Power District (OPPD) committed to follow the Electric Power Research Institute (EPRI) Report, "Seismic Evaluation Guidance: Screening, Prioritization and Implementation Details (SPID) for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic," (ADAMS Accession No. ML12333A170) as supplemented by the EPRI Report, "Seismic Evaluation Guidance: Augmented Approach for the Resolution of Fukushima Near-Term Task Force (NTTF) Recommendation 2.1: Seismic" (referred to as the Expedited Approach) (ADAMS Accession No. ML13102A142). OPPD submitted the re-evaluated seismic hazards (ADAMS Accession No. ML14097A087) for Fort Calhoun Station (FCS) in March 2014. The NRC staff conducted the screening and prioritization review of the submittal by assessing OPPD's screening evaluation and hazard analysis utilizing the endorsed SPID guidance. Accordingly, during the NRC screening and prioritization process, the staff identified that a determination could not be made and interactions with OPPD were needed to reach resolution. The staff identified FCS as a "conditional screen-in" for the purposes of prioritizing and conducting additional evaluations. On May 9, 2014, the NRC staff issued a letter (ADAMS Accession No. ML14111A147) documenting the NRC staff's screening results.
In accordance with the SPID and Expedited Approach guidance, the re-evaluated seismic hazard determines if additional seismic risk evaluations are warranted for a plant. The SPID guidance provides criteria for a plant with ground motion response spectra (GMRS) above the safe shutdown earthquake, but bounded by the Individual Plant Examination for External Events (IPEEE) capacity spectrum. To use the IPEEE capacity spectrum to screen out of conducting a seismic risk evaluation, the licensee needed to demonstrate the adequacy of FCS's IPEEE evaluation by meeting the criteria in the SPID. If the IPEEE capacity is greater than the GMRS in the 1-1OHz range, the plant screens out of conducting a seismic risk.
The following additional information is requested to support the NRC's final screening determination for FCS based on IPEEE adequacy:
Enclosure
- 1. Prior to restart of the unit, the as found condition of Class I structural members inside containment and in the auxiliary building were determined to be outside the current licensing basis. These issues are documented in a May 14, 2014, inspection report, "Fort Calhoun-NRC Integrated Inspection Report Number 05000285/2014007" (ADAMS Accession No. ML14134A410). In the FCS seismic hazard and screening report submittal of March 31, 2014, the licensee indicated that it will not perform a risk evaluation because the FCS IPEEE Hazard Spectra (IHS) exceeds the calculated GMRS. To support your conclusion, please describe how these structural elements were evaluated and found to have sufficient seismic capacity consistent with the IHS.
- 2. The FCS seismic hazard and screening report submittal indicated that a risk evaluation will not be performed because FCS's IPEEE high confidence of a low probability of failure spectrum exceeds the calculated GMRS. However, in considering the soil erosion observed during the 2011 flood at the site, please explain if the erosion and related impact could have potentially weakened the foundation supporting materials, and therefore affected the estimation of the site-specific GMRS.
- concurrence via e-mail OFFICE NRR/JLD/JHMB/PM NRR/DORULPL4-1/PM* NRR/JLD/JHMB/LA NRR/JLD/JHMB/BC NAME MBalazik FLvon Slent SWhaley DATE 07/14/14 07/15/14 07/14/14 07/16/14