ML15238B655

Interim Staff Response to Reevaluated Flood Hazards Submitted in Response to 10 CFR 50.54(f) Information Request - Flood-Causing Mechanism Reevaluation

ML15238B655
Person / Time
Site:	Hope Creek
Issue date:	09/10/2015
From:	Tekia Govan Japan Lessons-Learned Division
To:	Braun R Public Service Enterprise Group
Govan T, NRR/JLD, 415-6197
Shared Package
ML15238B660	List: ML15238B655 ML15243A502
References
TAC MF3789
Download: ML15238B655 (8)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 September 10, 2015 Mr. Robert Braun President and Chief Nuclear Officer PSEG Nuclear LLC-N09 P. 0. Box 236 Hancocks Bridge, NJ 08038

SUBJECT:

HOPE CREEK GENERATING STATION- INTERIM STAFF RESPONSE TO REEVALUATED FLOOD HAZARDS SUBMITTED IN RESPONSE TO 10 CFR 50.54(f) INFORMATION REQUEST - FLOOD-CAUSING MECHANISM REEVALUATION (TAC NO. MF3789)

Dear Mr. Braun:

The purpose of this letter is to provide a summary of the U.S. Nuclear Regulatory Commission (NRC) staff's assessment of the re-evaluated flood-causing mechanisms described in the March 12, 2014 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML14071A511) flood hazard reevaluation report (FHRR) submitted by PSEG Nuclear LLC (PSEG, the licensee) for Hope Creek Generating Station (Hope Creek), as well as supplemental information resulting from requests for additional information and audits.

By letter dated March 12, 2012, the NRC issued a request for information pursuant to Title 1O of the Code of Federal Regulations, Section 50.54(f) (hereafter referred to as the 50.54(f) letter)

(ADAMS Accession No ML12053A340). 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 March 30, 2015, the Commission provided Staff Requirements Memoranda (SRM) (ADAMS Accession 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 their 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 tables provided as an Enclosure to this letter. Table 1 provides the current design-basis flood hazard mechanisms. Table 2 provides the reevaluated flood hazard mechanisms; however, the reevaluated flood hazard mechanisms bounded by the current design-basis (Table 1) are not included.

R. Braun 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 Hope Creek. Further, the 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, 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 Hope Creek 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.

As stated above, Table 2 of the enclosure to this letter describes the reevaluated flood hazards that exceed the current design-basis. In order to complete its response to the information requested by Enclosure 2 to the 50.54(f) letter, the licensee is expected to submit an integrated assessment or a focused evaluation, as appropriate, to address these reevaluated flood hazards, 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).

R. Braun If you have any questions, please contact me at (301) 415-6197 or e-mail at tekia.govan@nrc.gov.

Sincerely, J;u~v.~~

Tekia V. Govan, Project Manager Hazards Management Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation Docket No. 50-354

Enclosure:

Summary of Results of Flooding Hazard Re-Evaluation Report cc w/encl: Distribution via Listserv

ENCLOSURE:

SUMMARY

TABLES OF REEVALUATED FLOOD HAZARD LEVELS

Hope Creek, Unit 1 Table 1. Current Design Basis Flood Hazards for Use in the MSA Mechanism Stillwater Waves/ Design Basis Reference I Elevation Run up Hazard I Elevation i Local Intense Precipitation I

12.1 ft Minimal 12.1 ft FHRR Table 3-1 NAVD88 NAVD88 Streams and Rivers I Powerblock/Service Water Intake 7.5 ft 12.5 ft 20.0 ft FHRR Section 1.2.2 Structure NAVD88 NAVD88 Failure of Dams and Onsite Water Control/Storage Structures Multiple Failures of Connonsville, 12.7ft 12.8 ft 25.5 ft FHRR Section 1.2.3 Pepacton and Tocks Island Dams NAVD88 NAVD88 Storm Surge Powerblock A 24.0 ft NAVD88

+-

6.2 ft I

30.2 ft NAVD88 FHRR Table 3-1 Powerblock 8 24.0 ft 10.6 ft 34.6 ft FHRR Section 1.2.4 NAVD88 NAVD88 Service Water Intake Structure 24.0 ft 20.6 ft 44.6 ft FHRR Section 1.2.4 NAVD88 NAVD88 Seiche I

No Impact No Impact No Impact FHRR Section 1.2.5 on the Site on the Site on the Site Identified Identified I Identified Tsunami 5.2 ft 12.1 ft 17 .3 ft FHRR Section 1.2.6 NAVD88 NAVD88 Ice-Induced Flooding No Impact No Impact No Impact FHRR Section 1.2.7 on the Site on the Site on the Site Identified Identified Identified

Hope Creek, Unit 1 Table 1. Current Design Basis Flood Hazards for Use in the MSA Mechanism Stillwater Waves/ Design Basis Reference ***----i Elevation Run up Hazard Elevation I Channel Migrations/Diversions No Impact No Impact No Impact FHRR Section 1.2.8 on the Site on the Site on the Site Identified Identified Identified Note 1: Reported values are rounded to the nearest one-tenth of a foot.

Note 2: Based on the NRG staff's independent (deterministic) hazard assessment using present-day regulatory guidance and methodologies of storm surge, the staff concludes that the site's current design basis remains bounded. For this reason, the staff concludes it is appropriate to utilize the current design basis storm surge elevation in conjunction with the mitigating strategies assessment.

Hope Creek, Unit 1 Table 2. Reevaluated Flood Hazards for Flood-Causing Mechanisms for Use in the MSA I  !

Mechanism Stillwater I I Waves/ Reevaluated i i Reference I

Elevation Run up Hazard I I

Elevation II I

Local Intense Precipitation 12.8 ft Minimal 12.8ft FHRR Section 3.1 NAVD88 NAVD88 I

I I

j Note 1: The licensee is expected to develop flood event duration parameters and applicable flood associated effects to conduct the MSA. The staff will evaluate the flood event duration parameters (including warning time and period of inundation) and flood associated effects during its review of the MSA.

Note 2: Reevaluated hazard mechanisms bounded by the current design basis (see Table 1) are not included in this table.

Note 3: Reported values are rounded to the nearest one-tenth of a foot.

PKG ML152388660; LTR: ML152388655; ENCL: ML15243A502 *via email OFFICE NRR/JLD/JHMB/PM NRR/JLD/LA NRO/DSEA/RHM1/TR* NRO/DSEA/RHM1/TL*

NAME TGovan Slent MLee KErwin DATE 09/02/15 09/01/15 09/09/15 09/09/15 OFFICE NRR/JLD/JHMB/BC NRR/JLD/JHMB/PM NAME MShams TGovan DATE 09/10/15 09/10/15