ML15314A747
| ML15314A747 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 11/12/2015 |
| From: | Tekia Govan Japan Lessons-Learned Division |
| To: | Franke J Susquehanna |
| Govan, Takia, NRR/JLD 415-6197 | |
| References | |
| TAC MF6037, TAC MF6038 | |
| Download: ML15314A747 (5) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 Mr. Jon A Franke Site Vice President Susquehanna Nuclear, LLC 769 Salem Boulevard NUCSB3 Berwick, PA 18603-0467 November 12, 2015
SUBJECT:
SUSQUEHANNA STEAM ELECTRIC STATION, UNITS 1 AND 2-CORRECTION TO INTERIM STAFF RESPONSE TO REEVALUATED FLOOD HAZARDS SUBMITTED IN RESPONSE TO 10 CFR 50.54(f) INFORMATION REQUEST - FLOOD-CAUSING MECHANISM REEVALUATION (TAC NOS. MF6037 AND MF6038)
Dear Mr. Franke:
By letter dated November 3, 2015 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML15303A314), the U.S. Nuclear Regulatory Commission (NRC) transmitted to you the Interim Staff Response to the reevaluated flood hazards for Susquehanna Steam Electric Station, Units 1 and 2 (Susquehanna). In that letter, Table 1 is referenced and contains the reevaluated hazards bounded by current design-basis for Susquehanna. Table 1 was inadvertently omitted from the document and not included'in the final version that was transmitted to you. This letter supersedes the November 3, 2015, letter with the only change being the inclusion of Table 1 in the Enclosure to this letter.
The purpose of this letter is to provide a summary of the NRC staff's assessment of the re-evaluated flood-causing mechanisms described in the March 3, 2015 (ADAMS Accession No. ML15063A319), flood hazard reevaluation report (FHRR) submitted by Susquehanna Nuclear, LLC (the licensee), previously as PPL Susquehanna, LLC, for Susquehanna.
By letter dated March 12, 2012 (ADAMS Accession No. ML12053A340), the NRC issued a request for information pursuant to Title 1 O of the Code of Federal Regulations, Section 50.54(f)
(hereafter referred to as the 50.54(f) letter). The request was issued as part of implementing lessons-learned from the accident at the Fukushima Dai-ichi nuclear power plant. Enclosure 2 to the 50.54(f) letter requested licensees to re-evaluate flood-causing mechanisms using present-day methodologies and guidance. Concurrently, with the reevaluation of flooding hazards, licensees were required to develop and implement mitigating strategies in accordance with NRC Order EA-12-049, "Requirements for Mitigation Strategies for Beyond-Design-Basis External Events" (ADAMS Accession No. ML12054A735). On i\\/larch 30, 2015, the Commission provided Staff Requirements Memoranda (SRM) (ADAMS Ar;cession No. ML15089A236) to COMSECY-14-0037, "Integration of Mitigating Strategies for Beyond-Design-Basis External Events and the Reevaluation of Flooding Hazards," dated November 21, 2014 (ADAMS Accession No. ML14309A256), affirming that licensees need to address the reevaluated flooding hazards within th~ir mitigating strategies for beyond-design-basis external events.
The NRC staff has reviewed the information submitted by the licensee and has summarized the results of the review in the table provided as an Enclosure to this letter. Table 1 provides the current design-basis flood hazard mechanisms. All of the reevaluated flood hazard mechanisms at Susquehanna are bounded by the current design-basis.
The NRC staff has concluded that the licensee's reevaluated flood hazards information, as summarized in the Enclosure, is suitable for the assessment of mitigating strategies developed in response to Order EA-12-049 (i.e., defines the mitigating strategies flood hazard information described in guidance documents currently being finalized by the industry and NRC staff) for Susquehanna. Further, the NRC staff has concluded that the licensee's reevaluated flood hazard information is a suitable input for other assessments associated with Near-Term Task Force Recommendation 2.1 "Flooding". The NRC staff plans to issue a staff assessment documenting the basis for these conclusions at a later time.
In addition, Nuclear Energy Institute (NEI) guidance document NEI 12-06 "Diverse and Flexible Coping Strategies (FLEX) Implementation Guide" is currently being revised. This revision will include a methodology to perform a Mitigating Strategies Assessment (MSA) with respect to the reevaluated flood hazards. Once this methodology is endorsed by the NRC, flood event duration parameters and applicable flood associated effects should be considered as part of the Susquehanna MSA. The NRC staff will evaluate the flood event duration parameters (including warning time and period of inundation) and flood-related associated effects developed by the licensee during the NRC staff's review of the MSA.
Because the reevaluated flood hazard mechanisms at Susquehanna are bounded by the current design-basis, it is unnecessary for the licensee to perform an integrated assessment or focused evaluation, as described in the NRC letter, "Coordination of Request for Information Regarding Flooding Hazard Reevaluation and Mitigating Strategies for Beyond-Design-Basis External Events" (ADAMS Accession No. ML15174A257). This letter describes the changes in the NRC's approach to the flood hazard reevaluations that were approved by the Commission in its SRM to COMSECY-15-0019, "Closure Plan for the Reevaluation of Flooding Hazards for Operating Nuclear Power Plants" (ADAMS Accession No. ML15209A682). Therefore, the NRC staff confirms that the licensee responded appropriately to Enclosure 2, of the 50.54(f) letter.
If you have any questions, please contact me at (301) 415-6197 or by e-mail at Tekia.Govan@nrc.gov.
Docket Nos. 50-387 and 50-388
Enclosure:
Summary of Results of Flooding Hazard Re-Evaluation Report cc w/encl: Distribution via Listserv Sincerely, Jluo Tekia V. Govan, Project Manager Hazards Management Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation
ENCLOSURE:
SUMMARY
TABLES OF REEVALUATED FLOOD HAZARD LEVELS
Susquehanna, Units 1 & 2 Table 1. Current Design Basis Flood Hazards for Use in the MSA Mechanism Stillwater Elevation Local Intense Precipitation Engineered Safeguards Service 694.8 ft MSL Water (ESSW) Pumphouse (South side)
ESSW Pumphouse Valve 697.3 ft MSL Chamber Common Diesel Generator 679.0 ft MSL Building Unit 1 Reactor Building 672.0 ft MSL Unit 2 Reactor Building 672.0 ft MSL Common Diesel 'E' Building 678.0 ft MSL:
Waves/
Run up 0.0 ft 0.0 ft 0.0 ft O.Oft O.Oft O.Oft Design Basis Hazard Elevation Reference 694.8 ft MSL Letter dated September 24, 2015 to the NRC, "Susquehanna Steam Electric Station Flood Hazards Reevaluation Report Information to Support Audit", ADAMS Accession No. ML15267A600.
697.3 ft MSL Email dated October 2, 2015 to the NRC, "Susquehanna: Follow-on Audit Question", ADAMS Accession No. ML15288A563.
679.0 ft MSL Letter dated September 24, 2015 to the NRC, "Susquehanna Steam Electric Station Flood Hazards Reevaluation Report Information to Support Audit", ADAMS Accession No. ML15267A600.
672.0 ft MSL Letter dated September 24, 2015 to the NRC, "Susquehanna Steam Electric Station Flood Hazards Reevaluation Report Information to Support Audit", ADAMS Accession No. ML15267A600.
672.0 ft MSL Letter dated September 24, 2015 to the NRC, "Susquehanna Steam Electric Station Flood Hazards Reevaluation Report Information to Support Audit, ADAMS Accession No. ML15267A600.
678.0 ft MSL:
Letter dated September 24, 2015 to the NRC, "Susquehanna Steam Electric Station Flood Hazards Reevaluation Report Information to Support Audit", ADAMS Accession No. ML15267A600.
Susquehanna, Units 1 & 2 Table 1. Current Design Basis Flood Hazards for Use in the MSA Mechanism Stillwater Waves/
Design Basis Reference I
Elevation Runup Hazard Elevation I Spray Pond 682.4 ft MSL 2.4 ft 684.8 ft MSL FSAR Table 4-3 I
I I
I Streams and Rivers Susquehanna River 545.7 ft MSL 2.3 ft 548.0 ft MSL FHRR Section 2.2.2 I
I I
Failure of Dams and Onsite Water Control/Storage Structures Offsite Dam Failure No Impact No Impact No Impact FHRR Section 2.2.3 and Section on the Site on the Site on the Site 2.2.3 & 2.2.7 Identified Identified Identified I
Cooling Tower Basin Rupture 694.8 ft MSL Not 694.8 ft MSL Letter dated September 24, 2015 to applicable the NRC, "Susquehanna Steam Electric Station Flood Hazards Reevaluation Report Information to Support Audit", ADAMS Accession No. ML15267A600.
I Storm Surge No Impact No Impact No Impact FHRR Section 2.2.4 on the Site on the Site on the Site i
Identified Identified Identified I
I I
I I
Seiche I
No Impact No Impact No Impact FHRR Section 2.2.4 on the Site on the Site on the Site I
Identified Identified Identified Tsunami No Impact No Impact I No Impact FHRR Section 2.2.4 on the Site on the Site i on the Site Identified Identified Identified
, Ice-Induced Flooding I
I I
No Impact No Impact No Impact I
FHRR Section 2.2.5 on the Site on the Site on the Site L
Identified Identified Identified
Susquehanna, Units 1 & 2 Table 1. Current Design Basis Flood Hazards for Use in the MSA I
I Mechanism Stillwater I
Waves/
Design Basis Reference Elevation i
Run up Hazard I
Elevation Channel Migrations/Diversions No Impact No Impact No Impact FHRR Section 2.2.6 on the Site on the Site on the Site Identified I
Identified Identified Note 1: Reported values are rounded to the nearest one-tenth of a foot.
PKG ML15303A323; LTR: ML15314A747; ENCL: ML15239B221 *via email OFFICE NRR/JLD/JHMB/PM NRR/JLD/JHMB/LA NRO/DSEAfRHMB2fTR*
NRO/DSENRHMB2/BC*
NAME TGovan Slent KSee ARivera-Varona DATE 11/10/2015 11/12/2015 10/26/2015 10/26/2015 OFFICE NRR/JLD/JHMB/BC NRR/JLD/JHMB/PM NAME MShams TGovan DATE 11/12/2015 11/12/2015