ML15321A063
| ML15321A063 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 12/10/2015 |
| From: | Minarik A Japan Lessons-Learned Division |
| To: | Mccartney E Point Beach |
| Minarik, Anthony, NRR/JLD 415-6185 | |
| References | |
| TAC MF6100, TAC MF6101 | |
| Download: ML15321A063 (7) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 Mr. Eric McCartney Site Vice President NextEra Energy Point Beach, LLC 6610 Nuclear Road Two Rivers, WI 54241-9516 December 10, 2015
SUBJECT:
POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 - INTERIM STAFF RESPONSE TO REEVALUATED FLOOD HAZARDS SUBMITTED IN RESPONSE TO 10 CFR 50.54(f) INFORMATION REQUEST - FLOOD-CAUSING MECHANISM REEVALUATION (TAC NOS. MF6100 AND MF6101)
Dear Mr. McCartney:
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, 2015 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML15071A413), flood hazard reevaluation report (FHRR) submitted by NextEra Energy Point Beach, LLC (NextEra, the licensee) for Point Beach Nuclear Plant, Units 1 and 2 (Point Beach),
as well as supplemental information resulting from requests for additional information and audits.
By letter dated March 12, 2012 (ADAMS Accession No. ML12053A340), the NRC issued a request for information pursuant to Title 10 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 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 flood hazard 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 hazard mechanisms bounded by the current design-basis (Table 1) are not included.
The NRC staff has concluded that the licensee's reevaluated flood hazards information, as summarized in Enclosure 1, 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 Point Beach. 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, the 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 Point Beach 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 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).
If you have any questions, please contact me at (301) 415-6185 or e-mail at Anthony.Minarik@nrc.gov.
Docket Nos. 50-266 and 50-301
Enclosure:
Summary of Results of Flooding Hazard Re-Evaluation Report cc w/encl: Distribution via Listserv Sincerely, Anth y 1narik~nager Hazards Management Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation
ENCLOSURE:
SUMMARY
TABLES OF REEVALUATED FLOOD HAZARD LEVELS
Point Beach, Units 1 & 2 Table 1. Current Design Basis Flood Hazards for Use in the MSA
~-------------
Mechanism Stillwater Waves/
Design Basis Reference Elevation Run up Hazard Elevation Local Intense Precipitation 608.9 ft Minimal 608.9 ft FHRR Table 3.1 NAVD88 NAVD88 Streams and Rivers Not included Not included Not included I
' Failure of Dams and Onsite Water Control/Storage Structures Not included Not included Not included I
I I
\\ Storm Surge II I
583.2 ft 6.6 ft 589.7 ft FHRR Section 3.4 I
NAVD88 I
NAVD88 i Seiche No Impact I
No Impact No Impact on the Site I on the Site on the Site Identified Identified Identified Tsunami Not included Not included Not included in DB in DB in DB I
I
~ Ice-Induced Flooding I
Not included
- Not included Not included I
in DB I
Channel Migrations/Diversions Not included Not included Not included in DB in DB in DB Note 1: Reported values are rounded to the nearest one-tenth of a foot.
Point Beach, Units 1 & 2 Table 2. Reevaluated Flood Hazards for Flood-Causing Mechanisms for Use in the MSA Mechanism Stillwater I
Waves/
Reevaluated Reference Elevation I
Runup Hazard I
Elevation Local Intense Precipitation 609.6 ft Minimal I
609.6 ft FHRR Table 4.2 I
NAVD88 NAVD88 i
i 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.
I I
I I
PKG ML15343A338 Letter ML15321A063; ENCL ML15336A953
- via email OFFICE NRR/JLD/JHMB/PM NRR/JLD/LA NRO/DSEA/RHM2/TR*
NRO/DSEA/RHM2/BC*
NAME AMinarik Slent PChaput ARivera-Varona DATE 11 /23/2015 11/18/2015 12/8/2015 12/8/2015 OFFICE NRR/JLD/JHMB/BC NRR/JLD/JHMB/PM NAME MShams AMinarik DATE 12/10/2015 12/10/2015