UNITED STATES 

NUCLEAR REGULATORY COMMISSION 

WASHINGTON, D.C. 20555-0001 

Vice President, Operations 

Entergy Nuclear Operations, Inc. 

Palisades Nuclear Plant 

27780 Blue Star Memorial Highway 

Covert, Ml 49043-9530 

December 23, 2015 

SUBJECT: PALISADES NUCLEAR PLANT - INTERIM STAFF RESPONSE TO 

REEVALUATED FLOOD HAZARDS SUBMITTED IN RESPONSE TO 

10 CFR 50.54(f) INFORMATION REQUEST - FLOOD-CAUSING 

MECHANISM REEVALUATION C~AC NO. MF6128) 

Dear Sir or Madam: 

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 11, 2015 (Agencywide Documents Access and Management System (ADAMS) 

Accession No. ML 15106A681 ), flood hazard reevaluation report (FHRR) submitted by Entergy 

Nuclear Operations, Inc. (Entergy, the licensee) for Palisades Nuclear Plant (Palisades), 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 10 of 

the Code of Federal Regulations, Section 50.54(f) (hereafter referred to as the 50.54(f) letter) 

(ADAMS Accession No. ML 12053A340). 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. ML 12054A735). On March 30, 2015, the Commission 

provided Staff Requirements Memoranda (SRM) (ADAMS Accession No. ML 15089A236) 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. ML 14309A256), 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 hazard mechanisms bounded by the current designbas1s (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 
- 2 -

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 

Palisades. 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 

Palisades 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. ML 15174A257). 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. ML 15209A682). 
- 3 -

If you have any questions, please contact me at (301) 415-2915 or e-mail at 

Victor. Hall@nrc.gov. 

Docket No. 50-255 

Enclosure: 

Summary of Results of Flooding 

Hazard Re-Evaluation Report 

cc w/encl: Distribution via Listserv 

Victor E. Hall, Project Manager 

Hazards Management Branch 

Japan Lessons-Learned Division 

Office of Nuclear Reactor Regulation 
ENCLOSURE: 

SUMMARY TABLES OF 

REEVALUATED FLOOD HAZARD LEVELS 
Palisades 

Table 1. Current Design Basis Flood Hazards for Use in the MSA 

Reference 

Elevation Run up Hazard 

r

---- Mechanism Stillwater r~aves/ Design Basis 

___________________ ----------------------------------- ___________________ _______ _ ___ E!!Y!!~_!.1__ _ __ ___________ ______________ _ __ _ _____ _ 

Local Intense Precipitation 

East Side of Service Building 

Site Other than Service Building 

(Ponding) 

Streams and Rivers 

Failure of Dams and Onsite 

Water Control/Storage 

Structures 

Storm Surge 

601.0 ft 

NGVD29 

0.5 ft Depth 

Not included 

in DB 

i 

I 

I 

Minimal 

Minimal 

Not included 

in DB 

Not included I Not included 

in DB I in DB 

I 

I 

I 

I 

594.1 ft I s.o ft 

NGVD29 I 

J 

601.0 ft 

NGVD29 

0.5 ft Depth 

Not included 

in DB 

Not included 

in DB 

602.1 ft 

NGVD29 

FHRR Section 2.3.1.1 

FHRR Section 2.3.1.1 & Table 4-1 

FHRR Table 4-1 

FHRR Table 4-1 

FHRR Table 4-1 

FHRR Table 4-4 

---------------+--------,-------r--------;---------------------

Seiche 

Tsunami 

No Impact ! No Impact 

on the Site i on the Site 

Identified I Identified 

J 

! 

No Impact 

on the Site 

Identified 

Not included I Not included Not included 

in DB I in DB in DB 

I 

--- - -- ----- --- ----- ------------------ ---- ------------------- +--- ------------ ------------ ------ ______________ ,, ------ ---- ----- ------ -------- ------- ---- ! 

Ice-Induced Flooding 

Channel Migrations/Diversions 

I 

Not included I Not included Not included 

in DB I in DB in DB 

I 

I 

! 

I 

Not included j Not included 

I 

I 

Not included 

FHRR Table 4-1 

FHRR Table 4-1 

FHRR Table 4-1 

FHRR Table 4-1 

----····-·------------------------------------------ _________________________ ____.J. _______________________________ ---------------------- ---------------------------·----------····-------- ---------

Note 1: Reported values are rounded to the nearest one-tenth of a foot. 

Note 2: For LIP-Scenario 2, the total stillwater ponding depth is reported to be up to a maximum of 0.5 ft. For total 

elevation, add ponding depth to ground elevation. 
Palisades 

Table 2. Reevaluated Flood Hazards for Flood-Causing Mechanisms for Use in the MSA 

Mechanism Stillwater Waves/ 1 Reevaluated 1 Reference 

Elevation Runup I Hazard 1 

-- -- -- - ------ -- -- - -- --- -- - --------- - -- -[-- - --- - ------- r- - ---- --- --- ---- r- --- - - - -- -- --- - --- -- ---- -- - -- --

,_____________________________ _ _________________________________________________ I -~l~y!ti<?~--- '. _________ _______ _ _ __ 

Local Intense Precipitation ! 

Service Building - East Side 

(Non-Category 1 Structure) 

Upper Level (Category 1 

Structures) 

Lower Level (Category 1 

Structures) 

-------

Storm Surge 

H.4 Combined Flood Event: 

Lakeward of Circulation Pipes 

H.4 Combined Flood Event: 

Landward of Circulation Pipes 

H.4 Combined Flood Event: 

Landward of Turbine Building 

H.4 Combined Flood Event: 

North of Turbine Building 

605.8 ft 

NGVD29 

626.1 ft 

NGVD29 

594.4 ft 

NGVD29 

593.9 ft 

NGVD29 

593.9 ft 

NGVD29 

593.9 

NGVD29 

593.9 

NGVD29 

I 

! 

I 

I 

I 

___J_ 

Minimal 

Minimal 

Minimal 

8.3 ft 

0.4 ft 

0.4 ft 

1.1 ft 

605.8 ft 

NGVD29 

626.1 ft 

NGVD29 

594.4 ft 

NGVD29 

602.2 ft 

NGVD29 

594.3 ft 

NGVD29 

594.3 

NGVD29 

595.0 

NGVD29 

FHRR Section 2.3.1.1 & Table 4-1 

FHRR Section 2.3.1.1 & 

Tables 4-1 and 5-2 

FHRR Section 2.3.1.1 & 

Tables 4-1 and 5-1 

------------" 

FHRR Section 3.9.2.1.2 

FHRR Table 4-5 & Figure 3-29 

FHRR Section 3.9.2.1.2 

FHRR Table 4-5 & Figure 3-29 

FHRR Section 3.9.2.1.2 

FHRR Table 4-5 & Figure 3-29 

FHRR Section 3.9.2.1.2 

FHRR Table 4-5 & Figure 3-29 

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. 
- 3 -

If you have any questions, please contact me at (301) 415-2915 or e-mail at 

Victor.Hall@nrc.gov. 

Docket No. 50-255 

Enclosure: 

Sincerely, 

IRA/ 

Victor E. Hall, Project Manager 

Hazards Management Branch 

Japan Lessons-Learned Division 

Office of Nuclear Reactor Regulation 

Summary of Results of Flooding 

Hazard Re-Evaluation Report 

cc w/encl: Distribution via Listserv 

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ADAMS Accession Nos.:PKG ML15356A766; LTR: ML15356A765; ENCL: ML15344A080 *via email 

OFFICE NRR/JLD/JHMB/PM NRR/JLD/LA NRO/DSEA/RHM2/TR* 

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DATE 12/22/15 12/22/15 12/21/15 

OFFICE NRO/DSEA/RHM 1 /BC* NRR/JLD/JHMB/BC NRR/JLD/JHMB/PM 

NAME CCook MShams VHall 

DATE 12/21/15 12/23/15 12/23/15 

OFFICIAL RECORD COPY