UNITED STATES 

NUCLEAR REGULATORY COMMISSION 

WASHINGTON, D.C. 20555-0001 

Mr. Anthony J. Vitale 

Site Vice President 

Entergy Nuclear Operations, Inc 

Palisades Nuclear Plant 

27780 Blue Star Memorial Highway 

Covert, Ml 49043-9530 

June 17, 2014 

SUBJECT: PALISADES NUCLEAR PLANT- STAFF ASSESSMENT OF THE FLOODING 

WALKDOWN REPORT SUPPORTING IMPLEMENTATION OF NEAR-TERM 

TASK FORCE RECOMMENDATION 2.3 RELATED TO THE FUKUSHIMA 

DAI-ICHI NUCLEAR POWER PLANT ACCIDENT (TAC NO. MF0257) 

Dear Mr. Vitale: 

On March 12, 2012, the U.S. Nuclear Regulatory Commission (NRC) issued a request for 

information letter per Title 10 of the Code of Federal Regulations, Section 50.54(f) (50.54(f) 

letter). The 50.54(f) letter was issued to power reactor licensees and holders of construction 

permits requesting addressees to provide further information to support the NRC staff's 

evaluation of regulatory actions that may be taken in response to lessons learned from Japan's 

March 11, 2011, Great Tohoku Earthquake and subsequent tsunami. The request addressed 

the methods and procedures for nuclear power plant licensees to conduct seismic and flooding 

hazard walkdowns to identify and address degraded, nonconforming, or unanalyzed conditions 

through the corrective action program, and to verify the adequacy of the monitoring and 

maintenance procedures. 

By letter dated November 27, 2012, Entergy Nuclear Operations, Inc. submitted a Flooding 

Walkdown Report as requested in Enclosure 4 of the 50.54(f) letter for the Palisades Nuclear 

Plant (PNP) site. By letter dated January 30, 2014, Entergy Nuclear Operations, Inc. provided a 

response to the NRC request for additional information for the staff to complete its 

assessments. 

By letter dated November 27, 2012, the licensee provided an acceptable schedule to complete 

the delayed walkdown items no later than June 1, 2014. The NRC staff reviewed the 

information provided and, as documented in the enclosed staff assessment, determined 

sufficient information was provided to be responsive to Enclosure 4 of the 50.54(f) letter. 
A. Vitale - 2 -

If you have any questions, please contact me at (301) 415-8371 or by e-mail at 

Mahesh.Chawla@nrc.gov. 

Docket No. 50-255 

Enclosures: 

Staff Assessment of Flooding Walkdown Report 

cc w/encls: Distribution via Listserv 

Sincerely, 

Mahesh L Chawla, Project Manager 

Plant Licensing Branch 111-1 

Division of Operating Reactor Licensing 

Office of Nuclear Reactor Regulation 
STAFF ASSESSMENT OF SEISMIC WALKDOWN REPORT 

NEAR-TERM TASK FORCE RECOMMENDATION 2.3 RELATED TO 

THE FUKUSHIMA DAI-ICHI NUCLEAR POWER PLANT ACCIDENT 

ENTERGY NUCLEAR OPERATIONS. INC.PALISADES NUCLEAR PLANT 

DOCKET NO. 50-255 

1.0 INTRODUCTION 

On March 12, 2012, 1 the U.S. Nuclear Regulatory Commission (NRC) issued a request for 

information per Title 10 of the Code of Federal Regulations, (1 0 CFR) Section 50.54(f) (50.54(f) 

letter) to all power reactor licensees and holders of construction permits in active or deferred 

status. The request was part of the implementation of lessons learned from the accident at the 

Fukushima Dai-ichi nuclear power plant. Enclosure 4, "Recommendation 2.3: Flooding,"2 to the 

50.54(f) letter requested licensees to conduct flooding walkdowns to identify and address 

degraded, nonconforming, or unanalyzed conditions using the corrective action program (CAP), 

verify the adequacy of monitoring and maintenance procedures, and report the results to the 

NRC. 

The 50.54(f) letter requested licensees to include the following: 

a. Describe the design basis flood hazard level(s) for all flood-causing mechanisms, 

including groundwater ingress. 

b. Describe protection and migration features that are considered in the licensing basis 

evaluation to protect against external ingress of water into systems, structures and 

components (SSCs) important to safety. 

c. Describe any warning systems to detect the presence of water in rooms important 

to safety. 

d. Discuss the effectiveness of flood protection systems and exterior, incorporated, 

and temporary flood barriers. Discuss how these systems and barriers were 

evaluated using the acceptance criteria developed as part of Requested Information 

item 1.h. 

e. Present information related to the implementation of the walkdown process (e.g., 

details of selection of the walkdown team and procedures) using the documentation 

template discussed in Requested Information item 1.j, including actions taken in 

response to the peer review. 

1 Agencywide Documents Access and Management System (ADAMS) Accession No. ML 12053A340 

2 ADAMS Accession No. ML 12056A050 

Enclosure 
- 2-

f. Results of the walkdown including key findings and identified degraded, 

nonconforming, or unanalyzed conditions. Include a detailed description of the 

actions taken or planned to address these conditions using guidance in Regulatory 

Issues Summary 2005-20, Revision 1, Revision to the NRC Inspection Manual Part 

9900 Technical Guidance, "Operability Conditions Adverse to Quality or Safety," 

including entering the condition in the corrective action program. 

g. Document any cliff-edge effects identified and the associated basis. Indicate those 

that were entered into the corrective action program. Also include a detailed 

description of the actions taken or planned to address these effects. 

h. Describe any other planned or newly installed flood protection systems or flood 

mitigation measures including flood barriers that further enhance the flood 

protection. Identify results and any subsequent actions taken in response to the 

peer review. 

In accordance with the 50.54(f) letter, Enclosure 4, Required Response Item 2, licensees were 

required to submit a response within 180 days of the NRC's endorsement of the flooding 

walkdown guidance. By letter dated May 21, 20123

, the Nuclear Energy Institute (NEI) staff 

submitted NEI 12-07, Revision 0, "Guidelines for Performing Verification Walkdowns of Plant 

Flood Protection Features" to the NRC staff to consider for endorsement. By letter dated 

May 31, 20124

, the NRC staff endorsed the walkdown guidance. 

By letter dated November 27, 2012, 5 Entergy Nuclear Operations Inc. (ENO, the licensee), 

provided a response to Enclosure 4 of the 50.54(f) letter Required Response Item 2, for the 

Palisades Nuclear Plant (PNP). The NRC staff issued a request for additional information (RAI) 

to the licensee regarding the available physical margin (APM) dated December 23, 20136

. The 

licensee responded by letter dated January 30, 20147

. 

The NRC staff evaluated the licensee's submittals to determine if the information provided in the 

walkdown report met the intent of the walkdown guidance and if the licensee responded 

appropriately to Enclosure 4 of the 50.54(f) letter. 

2.0 REGULATORY EVALUATION 

The SSCs important to safety in operating nuclear power plants are designed either in 

accordance with, or meet the intent of Appendix A to 10 CFR Part 50, General Design Criteria 

(GDC) 2: "Design Bases for Protection Against Natural Phenomena;" and Appendix A "Seismic 

and Geological Criteria for Nuclear Plants," to 10 CFR Part 100. Criteria 2 states that SSCs 

important to safety at nuclear power plants shall be designed to withstand the effects of natural 

phenomena such as earthquakes, tornadoes, hurricanes, floods, tsunami, and seiches without 

loss of capability to perform their safety functions. 

3 ADAMS Package Accession No. ML 121440522 

4 ADAMS Accession No. ML 12144A142 

5 ADAMS Accession No. ML 12332A377 

6 ADAMS Accession No. ML 13325A891 

7 ADAMS Accession No. ML 14034A168 
- 3 -

For initial licensing, each licensee was required to develop and maintain design bases that, as 

defined by 10 CFR 50.2, identify the specific functions to be performed by an SSC, and the 

specific values or ranges of values chosen for controlling parameters as reference bounds for 

the design. 

The design bases for the SSCs reflect appropriate consideration of the most severe natural 

phenomena that have been historically reported for the site and surrounding area. The design 

bases also reflect sufficient margin to account for the limited accuracy, quantity, and period of 

time in which the historical data have been accumulated. 

The current licensing basis (CLB) is the set of NRC requirements applicable to a specific plant, 

and a licensee's written commitments for ensuring compliance with, and operation within, 

applicable NRC requirements and the plant-specific design basis that are in effect. 

3.0 TECHNICAL EVALUATION 

3.1 Design Basis Flooding Hazard for Palisades Nuclear Plant 

The licensee reported that the design basis flood hazard for the site is the probable seiche 

flooding from Lake Michigan, with a maximum flood level of 594.1 ft mean sea level (MSL). The 

duration of this storm is not specified in the current licensing basis, but is stated to be 

"measured in minutes rather than hours." The probable maximum precipitation (PMP) of 25.5 

inches within 6 hours at the site is an additional design basis flood, with a stated flooding level 

of less than 6 inches above grade (590.0 ft MSL) at all safety related structures. 

Other flooding mechanisms included in the CLB and discussed in Section 2.1 of the Flooding 

Walkdown Report are wind wave activity and maximum water table. Both of these mechanisms 

are stated to produce flood elevations lower than the seiche flooding elevation. 

Based on the NRC staff's review, the licensee appears to have described the design basis flood 

hazard level requested in the 50.54(f) letter and is consistent with the walkdown guidance. 

3.2 Flood Protection and Mitigation 

3.2.1 Flood Protection and Mitigation Description 

The licensee stated that the CLB flood protection is to an elevation of 594.4 ft. The safety 

related buildings are designed to withstand flooding by the PMP event to a water depth of 6 

inches throughout the site and to a depth of five feet on the east side of the Service Building 

(non-safety related structure). There are incorporated or exterior passive features that prevent 

flooding and an "Acts of Nature" procedure that provides actions to be taken in the event of 

external flooding caused by natural phenomena. The facilities, systems, and equipment were 

designed to be protected against the seiche flood level of 594.1 ft and the six hour PMP. 

Safety-related SSCs are protected by being housed in Category 1 structures, designed to 

withstand the design flood or located above the maximum design basis flooding level. Site 

storm sewers and drainage ditches surrounding SSCs are designed to carry the majority of the 

PMP runoff. 
-4-

3.2.2 Incorporated and Exterior Barriers 

The licensee reported that the site has incorporated and/or exterior barriers that are 

permanently in-place, requiring no operator manual actions. These barriers include: walls and 

floors for the Auxiliary Building, Turbine Building, and the Screen House; and the concrete 

cement top of the Fuel Oil Tank T-10A, and tank penetration caps. 

3.2.3 Temporary Barriers and Other Manual Actions 

The licensee stated that the site has no temporary barriers nor manual actions that require 

operator action. The watertight doors in the Turbine Building and Auxiliary Building are 

considered incorporated active barriers, however are normally closed therefore do not require 

manual actions. 

3.2.4 Reasonable Simulation and Results 

The licensee did not perform reasonable simulation, because procedures are not credited in the 

CLB and temporary flood barriers are not necessary. 

3.2.5 Conclusion 

Based on the NRC staffs review, the licensee appears to have described protection and 

mitigation features as requested in the 50.54(f) letter and the walkdown guidance. 

3.3 Warning Systems 

The licensee reported that the current licensing basis at PNP does not credit any flood warning 

systems for external flood protection. 

Based on the NRC staff's review, the licensee appears to have provided information to describe 

any warning systems, as requested in the 50.54(f) letter and consistent with the walkdown 

guidance. 

3.4 Effectiveness of Flood Protection Features 

The licensee determined that there were no deficiencies and that the flood protection features at 

PNP are designed to withstand design basis external flooding events. 

Based on the NRC staff's review, the licensee appears to have discussed the effectiveness of 

flood protection features as requested in the 50.54(f) letter and consistent with the walkdown 

guidance. 

3.5 Walkdown Methodology 

By letter dated June 8, 2012, 8 the licensee responded to the 50.54(f) letter that they intended to 

utilize the NRC endorsed walkdown guidelines contained in NEI 12-07, "Guidelines for 

8 ADAMS Accession No. ML 12163A533 
- 5-

Performing Verification Walkdowns of Plant Flood Protection Features." The licensee's 

walkdown submittal dated November 27, 2012, indicated that the licensee implemented the 

walkdowns consistent with the intent of the guidance provided in NEI 12-07. The licensee did 

not identify any exceptions from NEI 12-07. 

Based on the NRC staff's review, the licensee appears to have discussed the effectiveness of 

flood protection features as requested in the 50.54(f) letter and consistent with the walkdown 

guidance. 

3.6 Walkdown Results 

3.6.1 Walkdown Scope 

The licensee performed walkdowns of 36 flood protection features including walls, floors, 

penetration seals, internal conduits, manhole covers, watertight doors, storm drains, and roof 

drains. 

The licensee did not discuss if different modes of operation or concurrent environmental 

conditions were considered for the flooding walkdowns, however the CLB does not require 

consideration of different modes nor concurrent environmental conditions, therefore the intent of 

the walkdown guidance has been met. 

The licensee did use acceptance criteria in accordance with NEI 12-07. The licensee also used 

ENO procedures associated with condition monitoring of maintenance rule structures per 

10 CFR 50.65. In addition, the maintenance procedures for the inspection of penetration seals 

were used as a reference in determining the acceptance criteria. 

3.6.2 Licensee evaluation of flood protection effectiveness. key findings. and identified 

deficiencies 

The licensee performed an evaluation of the overall effectiveness of the plant's flood protection 

features. The main flood protection features were assessed to be capable of withstanding the 

design basis external flooding event. Barriers were, for the most part determined to be 

functional, with a junction boxes and electrical penetrations requiring flood seals to be installed. 

In addition one inch holes were discovered in manhole covers throughout the site, for use as 

crowbar insertion points. The licensee determined that the holes would allow only a small 

amount of water ingress through the manhole covers. The inundation of the specific manholes 

does not result in flooding of safety related structures, systems, and components due to the low 

volume of water that enters through holes. 

NEI 12-07 defines a deficiency as follows: "a deficiency exists when a flood protection feature is 

unable to perform its intended function when subject to a design basis flooding hazard." The 

licensee did not identify deficiencies because of the flood walkdowns. 

NEI 12-07 specifies that licensees identify observations in the corrective action program (CAP) 

that were not yet dispositioned at the time the walkdown report was submitted. ENO did not 

identify observations awaiting disposition. 
- 6-

Potential deficiencies were described in Section 7.3 of the Walkdown Report. This section 

describes actions that are required for the plant to fully comply with plant design requirements, 

and the CAP process is being used to track these issues. There are 10 actions listed in this 

section. 

3.6.3 Flood Protection and Mitigation Enhancements 

The licensee determined that no enhancements were necessary. 

3.6.4 Planned or newly installed features 

The licensee did not determine that changes were necessary by the flood walkdowns. 

3.6.5 Deficiencies Noted and Actions Taken or Planned to Address 

Licensee noted the following deficiencies and actions have been taken or planned to address 

the deficiencies: 

• One inch holes used to lift covers at all manholes. The licensee determined that the 

holes do not allow enough flooding to compromise safety. 

• Several electrical junction boxes not protected against flooding or material degradation 

that reduced flood protection. 

• Service Water Pump pressure switches not protected against flooding. 

• Card reader conduits not sealed against flooding. 

• Penetrations for instrument air lines not sealed. 

The licensee entered all deficiencies into the corrective action program, and all were addressed 

prior to the completion of the walkdown. Operability was determined, and all features can 

perform their flood protection function. 

3.6.6 Staff analysis of walkdowns 

NRC staff reviewed the licensee walkdown report dated November 27, 2012. The staff also 

reviewed the additional information in conjunction with the submitted walkdown report. 

As part of the walkdown effort, the licensee evaluated the capability of flood protection features 

by conducting a set of visual inspections. The features were confirmed to be in place and 

available and also to be capable of performing their intended flood protection or mitigation 

functions. No changes or enhancements to flood protection or mitigation features were 

identified as a result of the walkdowns. 

During the walkdowns, the items listed in Subsection 3.6.5 above were identified as not 

immediately acceptable; however, corrective actions were identified and are being taken. The 

actions taken included operability determinations that demonstrated that features could still 

perform their intended function. 

Based on the NRC staff's review, the licensee appears to have provided results of the walkdown 

and described any other planned or newly installed flood protection systems or flood mitigation 
- 7 -

measures as requested in the 50.54(f) letter and consistent with the walkdown guidance. Based 

on the information provided in the licensee's submittals, the NRC staff concludes that the 

licensee's implementation of the walkdown process meets the intent of the walkdown guidance. 

3.6. 7 Available Physical Margin 

NRC staff issued a request for additional information RAI to the licensee regarding the APM 

dated December 23, 20139

. The licensee responded by letter dated January 30, 201410. The 

licensee has reviewed their APM determination process, and entered any unknown APMs into 

their CAP. The staff reviewed the response, and concluded that the licensee met the intent of 

the APM determination per NEI 12-07 

Based on the NRC staff's review, the licensee appears to have documented the information 

requested for any cliff-edge effects, as requested in the 50.54(f) letter and consistent with the 

walkdown guidance. Further, the NRC staff reviewed the response, and concludes that the 

licensee met the intent of the APM determination per NEI12-07. 

3. 7 NRC Oversight 

3.7.1 Independent Verification by Resident Inspectors 

On June 27, 2012, the NRC issued Temporary Instruction (TI) 2515/187 "Inspection of NearTerm Task Force Recommendation 2.3 Flooding Walkdowns." In accordance with the Tl, NRC 

inspectors independently verified that the Palisades licensee implemented the flooding 

walkdowns consistent with the intent of the walkdown guidance. Additionally, the inspectors 

independently performed walkdowns of a sample of flood protection features. The inspection 

report dated February 11, 2013, documents the results of this inspection. No findings of 

significance were identified. 

4.0 SSCs NOT WALKED DOWN 

The licensee identified restricted access features. 

The licensee provided justification for the delay in walkdowns of restricted access features. Two 

restricted access features require boroscoping, and the third is in an energized junction box that 

can only be accessed during an outage. 

4.1 Restricted Access 

The licensee described two buried diesel floor drain check valves that were not inspected due to 

being classified as restricted access features. The license provided reasonable assurance that 

the valves will perform their flood protection functions, as they are a part of a periodic 

Preventative Maintenance activity. In addition, a conduit watertight seal was also classified as 

restricted access. The licensee provided reasonable assurance that the seal will perform the 

9 ADAMS Accession No. ML 13325A891 

10 ADAMS Accession No. ML 14034A168 
- 8 -

designed flood protection function .The licensee committed to inspecting all of these features by 

June 1, 2014. 

4.2 Inaccessible Features 

The licensee did not identify any inaccessible features. 

5.0 CONCLUSION 

The NRC staff concludes that the licensee's implementation of flooding walkdown methodology 

meets the intent of the walkdown guidance. The staff concludes that the licensee, through the 

implementation of the walkdown guidance activities and, in accordance with plant processes 

and procedures, verified the plant configuration with the current flooding licensing basis; 

addressed degraded, nonconforming, or unanalyzed flooding conditions; and verified the 

adequacy of monitoring and maintenance programs for protective features. Furthermore, the 

staff notes that no immediate safety concerns were identified. By letter dated November 27, 

2012, the licensee provided an acceptable schedule to will complete the delayed walkdown 

items no later than June 1, 2014,The NRC staff reviewed the information provided and 

determined that sufficient information was provided to be responsive to Enclosure 4 of the 

50.54(f) letter. 
A. Vitale - 2 -

If you have any questions, please contact me at (301) 415-8371 or by e-mail at 

Mahesh. Chawla@nrc. gov. 

Sincerely, 

IRA! 

Mahesh L Chawla, Project Manager 

Plant Licensing Branch 111-1 

Division of Operating Reactor Licensing 

Office of Nuclear Reactor Regulation 

Docket No. 50-255 

Enclosures: 

Staff Assessment of Flooding Walkdown Report 

cc w/encls: Distribution via Listserv 

DISTRIBUTION: 

PUBLIC 

LPL3-1 R/F 

RidsNroDsea Resource 

RidsNrrDorl Resource 

RKuntz, NRR 

RidsOgcMaiiCenter Resource 

RidsOpaMail Resource 

RidsNrrLAMHenderson Resource 

RidsNrrPMPalisades Resource 

NChokshi, NRO 

CCook, NRO RKaras, NRO 

EMiller, NRR RidsAcrsAcnw MaiiCTR Resource 

ADAMS Accession Number: ML 14128A569 

OFFICE DORLILP3-1/PM JLD/PMB/PM 

NAME MChawla EM iller 

*DATE 06/16/14 06/16/14 

OFFICE DSEA/RGS1* DORL!LPL3-1 /BC 

NAME RKaras RCa rison 

DATE 04/18/14 06/ 17/14 

OFFICIAL RECORD COPY 

RidsRgn3MaiiCenter Resource 

JNick, EDO Rill 

PChaput, NRO 

RidsNrrDorllpl3-1 Resource 

SFianders, NRO 

MJardaneh, NRO 

* concurrence by e-mail 

DORLILPL3-1 /LA 

MHenderson 

06/11/14 

DORLILPL3-1 /PM 

MChawla 

06/17/14