ML15334A413
| ML15334A413 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 12/04/2015 |
| From: | Tekia Govan Japan Lessons-Learned Division |
| To: | Weber L Indiana Michigan Power Co |
| Govan, Tekia NRR/JLD 415-6197 | |
| References | |
| TAC MF6096, TAC MF6097 | |
| Download: ML15334A413 (7) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 Mr. Lawrence J. Weber Senior Vice President and Chief Nuclear Officer Indiana Michigan Power Company Nuclear Generation Group One Cook Place Bridgman, Ml 49106 December 4, 2015
SUBJECT:
DONALD C. COOK 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. MF6096 AND MF6097)
Dear Mr. Weber:
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 6, 2015 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML15069A334), flood hazard reevaluation report (FHRR) submitted by Indiana Michigan Power Company (the licensee) for Donald C. Cook Nuclear Plant, Units 1 and 2 (D. C Cook),
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 1 O 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 COM-SECY-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.
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 D.C. Cook. 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 D.C. Cook 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).
If you have any questions, please contact me at (301) 415-6197 or e-mail at Tekia.Govan@nrc.gov.
Docket Nos. 50-315 and 50-316
Enclosure:
Summary of Results of Flooding Hazard Re-Evaluation Report cc w/encl: Distribution via Listserv Sincerely, Jzt0--V.~
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
D. C. Cook, 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 I Local Intense Precipitation I
Not included : Not included Not included FHRR Table 4-1 I
in DB in DB in DB Streams and Rivers I I Not included Not included Not included FHRR Table 4-1 in DB in DB in DB Failure of Dams and Onsite Water Control/Storage I Structures I
Not included Not included Not included FHRR Table 4-1 in DB in DB in DB Storm Surge Not included Not included Not included FHRR Table 4-1 i
I i Seiche Seiche in Lake Michigan Shore 594.6 ft Not 594.6 ft FHRR Table 4-1 NGVD29 applicable NGVD29
- Tsunami I
Not included Not included Not included FHRR Table 4-1 in DB in DB in DB
! Ice-Induced Flooding Not included Not included Not included FHRR Table 4-1 in DB in DB in DB i
I I Channel Migrations/Diversions Not included Not included Not included FHRR Table 4-1 in DB in DB in DB Note 1: Reported values are rounded to the nearest one-tenth of a foot.
D. C. Cook, Units 1 & 2 Table 2. Reevaluated Flood Hazards for Flood-Causing Mechanisms for Use in the MSA Mechanism Stillwater Waves/
Reevaluated Reference Elevation I
Run up Hazard Elevation Local Intense Precipitation 1-DR-TUB201 594.8 ft Minimal 594.8 ft FHRR Table 3-2 (Turbine Building Unit 1 West NGVD29 NGVD29 Rollup Door) 2-DR-TUB220 596.0 ft Minimal 596.0 ft FHRR Table 3-2 (Turbine Building Unit 2 West NGVD29 NGVD29 Rollup Door) 2-DR-TUB260 609.2 ft Minimal 609.2 ft FHRR Table 3-2 (Turbine Building Unit 2 East NGVD29 NGVD29 Rollup Door)
Valve-Shed RWST 1-TK-33 609.9 ft Minimal 609.9 ft I
FHRR Table 3-2 NGVD29 NGVD29 I
Valve-Shed PWST/CST 1 609.9 ft Minimal 609.9 ft FHRR Table 3-2 NGVD29 NGVD29 Valve-Shed RWST 2-TK-33 609.5 ft Minimal 609.5 ft FHRR Table 3-2 NGVD29 NGVD29 Valve-Shed PWST/CST 2 609.6 ft Minimal 609.6 ft FHRR Table 3-2 I
NGVD29 I
NGVD29 I
I Supplemental Diesel Generators 609.6 ft Minimal 609.6 ft FHRR Table 3-2 NGVD29 NGVD29 1-DR-TUB253 I
609.8 ft Minimal 609.8 ft FHRR Table 3-2 (Turbine Building Unit 1 East NGVD29 NGVD29 Rollup Door) 12-DR-AUX381 609.9 ft Minimal 609.9 ft FHRR Table 3-2 (Auxiliary Building North Rollup NGVD29 NGVD29 Door)
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.
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PKG ML15334A424 LTR: ML15334A413 ENCL: ML15327A184 *via email OFFICE NRR/JLD/JHMB/PM NRR/JLD/LA NRO/DSEA/RHM2/TR*
NAME TGovan Slent KQuinlan DATE 12/2/2015 12/2/2015 11/24/2015 OFFICE NRO/DSEA/RHM2/TL*
NRR/JLD/JHMB/BC NRR/JLD/JHMB/PM NAME ARivera-Varona MS hams TGovan DATE 11/24/2015 12/4/2015 12/4/2015