JAFP-14-0128, Follow-up to Request for Information Pursuant to 10 CFR 50.54(f) Regarding the Seismic Aspects of Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident

Follow-up to Request for Information Pursuant to 10 CFR 50.54(f) Regarding the Seismic Aspects of Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident

ML14339A773
Person / Time
Site:	FitzPatrick
Issue date:	12/05/2014
From:	Brian Sullivan Entergy Nuclear Northeast, Entergy Nuclear Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
JAFP-14-0128
Download: ML14339A773 (16)

Text

Entergy Nuclear Northeast Entergy Nuclear Operations, Inc.

James A. FitzPatrick NPP P.O. Box 110 Lycoming, NY 13093 Tel 315-342-3840 Brian R. Sullivan Site Vice President - JAF JAFP-14-0128 December 5, 2014 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

Subject:

Follow-up to Request for Information Pursuant to 10 CFR 50.54(f) Regarding the Seismic Aspects of Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident James A. FitzPatrick Nuclear Power Plant Docket No. 50-333 License No. DPR-059

Reference:

1. NRC letter to Entergy, Request for Information (RFI) Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendations 2.1, 2.3, and 9.3 of the NTTF Review of Insights from the Fukushima Dai-ichi Accident, ML12053A340, dated March 12, 2012

2. Entergy letter to NRC, Seismic Hazard and Screening Report (CEUS Sites), Response to NRC RFI Pursuant to 10 CFR 50.54(f) Regarding Recommendation 2.1 of the NTTF Review of Insights from the Fukushima Dai-ichi Accident, JAFP-14-0039, dated March 31, 2014

3. Entergy letter to NRC, Response to Request for Additional Information (RAI) Associated with Near-Term Task Force (NTTF) Recommendation 2.1, Seismic Hazard and Screening Report, JAFP-14-0102, dated August 21, 2014

4. Entergy letter to NRC, Entergys Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding the Seismic Aspects of Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident, JAFP-13-0056, dated April 29, 2013

5. NEI letter, Proposed Path Forward for NTTF Recommendation 2.1:

Seismic Reevaluations, ML13101A379, dated April 9, 2013

6. NEI letter, Relay Chatter Reviews for Seismic Hazard Screening, ML13281A308, dated October 3, 2013

JAFP-14-0128 Page 2 of 2

Dear Sir or Madam:

On March 12, 2012, the NRC issued Reference 1 to all power reactor licensees. By Reference 2, Entergy Operations, Inc. (Entergy) provided the Seismic Hazard and Screening Reports for James A. FitzPatrick Nuclear Power Plant (JAF) requested by Reference 1. In Reference 3, JAF responded to a request tor additional information (RAI). The NRC contacted JAF to discuss the responses and based on the telecom communications three issues are being addressed by this letter.

First, provide a basis for the IPEEE high confidence of a low probability of failure (HCLPF)

Spectrum (IHS) for the block walls at JAF. This basis is contained in the Enclosure.

Second, in the RAI response [Reference 3] JAF stated its intention to perform a Relay Chatter Review. The Nuclear Energy Institute (NEI) letter dated April 9, 2013 [Reference 5] proposed a schedule to implement the Fukushima Near-Term Task Force (NTTF) Recommendation 2.1.

JAF committed to follow this schedule [Reference 4]. This schedule includes a group of risk evaluations due by June 30, 2017. Subsequently, a new NEI letter dated October 3, 2013

[Reference 6], proposed that the industry should also perform Relay Chatter Reviews. With this letter JAF commits to perform the Relay Chatter Reviews at the same schedule as the risk evaluations.

Third, the Seismic Hazard and Screening Report [Reference 2] concluded that JAF screened out of the High Frequency Confirmation and the seismic risk evaluation (seismic probabilistic risk assessment (SPRA), or a seismic margin assessment (SMA)); however, upon further evaluation, JAF will continue to perform the High Frequency Confirmation per the commitment made in Reference 4.

In conclusion, the evaluations to be performed per the NEI schedule [Reference 5] include Spent Fuel Pool Evaluation, High Frequency Confirmation, and Relay Chatter Review. In addition, JAF will submit the Expedited Seismic Evaluation Process (ESEP) by December 31, 2014, per the NEI schedule. This letter contains a new regulatory commitment in the Attachment. If you have any questions regarding this letter, please contact Chris M. Adner, Regulatory Assurance Manager, at 315-349-6766.

I declare under penalty of perjury that the foregoing is true and correct. Executed on 5th day of December, 2014.

Sincerely, BRS/CMA/mh

Enclosure:

Project 148115.50: Generation of High Confidence of Low Probability of Failure for Unreinforced Block Walls

Attachment:

Regulatory Commitments cc: NRC Regional Administrator NRC Resident Inspector Mr. Douglas Pickett, Senior Project Manager Mr. Michael Balazik, Project Manager Ms. Bridget Frymire, NYSPSC Mr. John B. Rhodes., President NYSERDA

JAFP-14-0128 Page 2 of 2

Dear Sir or Madam:

On March 12, 2012, the NRC issued Reference 1 to all power reactor licensees. By Reference 2, Entergy Operations, Inc. (Entergy) provided the Seismic Hazard and Screening Reports for James A. FitzPatrick Nuclear Power Plant (JAF) requested by Reference 1. In Reference 3, JAF responded to a request for additional information (RAI). The NRC contacted JAF to discuss the responses and based on the telecom communications three issues are being addressed by this letter.

First, provide a basis for the IPEEE high confidence of a low probability of failure (HCLPF)

Spectrum (IHS) for the block walls at JAF. This basis is contained in the Enclosure.

Second, in the RAI response [Reference 3] JAF stated its intention to perform a Relay Chatter Review. The Nuclear Energy Institute (NEI) letter dated April 9, 2013 [Reference 5] proposed a schedule to implement the Fukushima Near-Term Task Force (NTTF) Recommendation 2.1.

JAF committed to follow this schedule [Reference 4]. This schedule includes a group of risk evaluations due by June 30, 2017. Subsequently, a new NEI letter dated October 3, 2013

[Reference 6], proposed that the industry should also perform Relay Chatter Reviews. With this letter JAF commits to perform the Relay Chatter Reviews at the same schedule as the risk evaluations.

Third, the Seismic Hazard and Screening Report [Reference 2] concluded that JAF screened out of the High Frequency Confirmation and the seismic risk evaluation (seismic probabilistic risk assessment (SPRA), or a seismic margin assessment (SMA)); however, upon further evaluation, JAF will continue to perform the High Frequency Confirmation per the commitment made in Reference 4.

In conclusion, the evaluations to be performed per the NEI schedule [Reference 5] include Spent Fuel Pool Evaluation, High Frequency Confirmation, and Relay Chatter Review. In addition, JAF will submit the Expedited Seismic Evaluation Process (ESEP) by December 31, 2014, per the NEI schedule. This letter contains a new regulatory commitment in the Attachment. If you have any questions regarding this letter, please contact Chris M. Adner, Regulatory Assurance Manager, at 315-349-6766.

I declare under penalty of perjury that the foregoing is true and correct. Executed on 5th day of December, 2014.

Sincerely, Brian R. Sullivan Site Vice President BRS/CMA/mh

Enclosure:

Project 148115.50: Generation of High Confidence of Low Probability of Failure for Unreinforced Block Walls

Attachment:

Regulatory Commitments cc: NRC Regional Administrator NRC Resident Inspector Mr. Douglas Pickett, Senior Project Manager Mr. Michael Balazik, Project Manager Ms. Bridget Frymire, NYSPSC Mr. John B. Rhodes., President NYSERDA

JAFP-14-0128 Enclosure Project 148115.50: Generation of High Confidence of Low Probability of Failure for Unreinforced Block Walls (10 Pages)

11 November 2014 Mr. Richard Drake Civil / Structural Design Engineering Supervisor Fukushima Fleet Seismic Lead Indian Point Energy Center l Design Engineering 450 Broadway Buchanan, NY 10511 Project 148115.50 - James A. Fitzpatrick Nuclear Power Station Expedited Seismic Evaluation Program Support - Line Item 70 Re: Generation of High Confidence of Low Probability of Failure for Unreinforced Block Walls at the James A. Fitzpatrick Nuclear Power Plant, Lycoming, NY

Dear Mr. Drake:

Entergy submitted a response to a U.S. Nuclear Regulatory Commission (USNRC) Request for Additional Information (RAI) associated with the Near-Term Task Force (NTTF)

Recommendation 2.1 on 21 August 2014 (JAFP-14-0102). RAI 2 related to the seismic high confidence of a low probability of failure (HCLPF) calculations associated with four block walls (EGB-272-6, 7, 9, 10) that were modified as a result of the Individual Plant Examination for External Events (IPEEE) program. On 21 October 2014, the USNRC held a conference call to discuss the Entergy response to this RAI on the subject block walls. Simpson Gumpertz &

Heger Inc. (SGH) developed a new seismic HCLPF calculation for Entergy for these walls, and used the methods documented by the Department of Energy (DOE) for the evaluation of existing block walls as the basis for this HCLPF (DOE/EH-0545, Seismic Evaluation Procedure for Equipment in U.S. Department of Energy Facilities [1]). During that conference call, the USNRC requested that additional clarification be provided on the use of this DOE/EH-0545 methodology to develop seismic HCLPFs, and to have Entergy provide some insights on the factor between the HCLPF and the median fragility level for these block walls.

The purpose of this letter is to address these two USNRC requests relative to the James A.

Fitzpatrick Nuclear Power Plant (JAF) block wall HCLPF calculations. Section 1 provides additional clarification on the development of the block wall HCLPFs, as well as two sensitivity studies conducted to provide additional verification that the block wall HCLPFs provided in the 21 August 2014 submittal are appropriate for the subject walls. Section 2 provides some discussion on the factors which would be included within a fragility analysis of unreinforced block walls to develop a median capacity.

Entergy - Project 148115.50 11 November 2014

1. DEVELOPMENT OF HCLPF CAPACITIES The HCLPF methodology is described in detail in Electric Power Research Institute (EPRI)

NP-6041-SLR1 [2]. However, EPRI NP-6041-SLR1 [2] does not provide specific guidance on the capacity evaluation methods for unreinforced block walls. DOE/EH-0545 [1] contains block wall evaluation guidance and is considered a valid technical reference to supplement the guidance of EPRI NP-6041-SLR1. This reference has been the source of unreinforced block wall HCLPF calculations in many of the past Seismic Probabilistic Risk Assessments (SPRAs) / Seismic Margin Assessment (SMAs) and was basis for the development of the HCLPF levels by SGH (Calculation No. 148115-CA-003 [3]).

Subsequent to the 21 October conference call with the USNRC, SGH developed an alternative HCLPF calculation for the subject block walls to serve as a sensitivity study. The alternative HCLPF incorporated the criteria documented in ASCE/SEI 43-05 [4] for rocking of rigid bodies to characterize the relationship between the best estimate capacity to the design level capacity.

This sensitivity study resulted in a HCLPF level very close to the originally generated HCLPF and provided additional support to the reported block wall HCLPF results. As a further check on the HCLPF developed for these block walls, SGH consulted with an independent expert, Dr. Robert Kennedy (Principal Investigator on the EPRI NP-6041-SLR1 Seismic Margins report and author of several technical reports referenced in the DOE/EH-0545 report on block wall evaluations). Dr. Kennedy agreed with the use of the DOE/EH-0545 [1] approach to develop the HCLPF but suggested that SGH incorporate one change to include frequency shifting to address the uncertainty in the block wall fundamental response modes. This second sensitivity study resulted in a slightly lower HCLPF value, but was again very close to the original HCLPF estimate.

Presented below are brief descriptions of the original evaluation along with the two sensitivity studies that were conducted to validate the HCLPF estimate and to assess the sensitivity of the assumptions made in the analysis. All three of these HCLPF estimates result in plant-level HCLPFs that greatly exceed the ground motion response spectra (GMRS) between 1 Hz and 10 Hz. Sections 1.1 through 1.3 describe each of these three methods used to develop estimates of the JAF block wall HCLPFs. Section 1.4 contains a summary of the key parts of the calculations for each of these three approaches to develop the block wall HCLPF.

Section 1.5 summarizes the results of these sensitivity studies and provides the comparison to the original plant-level HCLPF for JAF, as well as the new GMRS.

1.1 Original SGH HCLPF For the purposes of discussion and as a point of comparison, relevant portions of the original SGH calculation (Calculation No. 148115-CA-003 [3]) that support the 21 August 2014 Entergy submittal are summarized and reproduced below.

As noted above, DOE/EH-0545 [1] provides procedures for the evaluation of multiple configurations of unreinforced block walls. As described in SGH Calculation No. 148115-CA-003 [3], the JAF block walls are laterally supported at the top and bottom and meet the criteria for the reserve energy method in DOE/EH-0545 [1]. The reserve energy method stipulates the following procedure to determine the spectral acceleration capacity, SAP, for block walls laterally supported at the top and bottom:

Entergy - Project 148115.50 11 November 2014 Where:

t = Actual thickness of concrete block b = Effective wall thickness

= 0.9t H = Wall height from base to top of wall g = Acceleration of gravity

= Capacity reduction factor

= 0.67 per DOE/EH-0545 H = Specified out-of-plane displacement Using the spectral acceleration capacity, the effective frequency of the block wall rocking is calculated as:

The spectral acceleration demand at the effective rocking frequency, SAD, is determined from the corresponding in-structure response spectrum. DOE/EH-0545 [1] specifies 5% damping for analysis of block walls by the reserve energy method.

The capacity-to-demand ratio, SAP / SAD, is then calculated using the spectral acceleration demand at the determined frequency. The maximum SAP / SAD at any given out-of-plane displacement, H¸ multiplied by the peak ground acceleration (PGA) of the input ground motion is the HCLPF capacity of the block wall.

1.2 Sensitivity Study 1 - DOE/EH-0545 Methodology with ASCE/SEI 43-05 Factor of Safety The mechanism in the DOE/EH-0545 [1] reserve energy capacity calculation for a wall restrained at the top assumes that the wall cracks and rotates at some height above its base.

After cracking, the wall separates into two rigid bodies that are in contact at the crack location.

Under out-of-plane seismic response, the two bodies rock about their supports.

While ASCE/SEI 43-05 [4] does not have an equivalent reserve energy capacity equation for a two rigid body rocking it does allow for rocking of unanchored rigid components as outlined in Section 7.1. ASCE/SEI 43-05, Section 7.1 provides the criteria that the best estimate of the

Entergy - Project 148115.50 11 November 2014 wall deformation should incorporate a Factor of Safety (FS) of 2.0 for rocking. It also states the best-estimate can be defined using approximate methods outlined in ASCE 43-05 Appendix A.

The approximate methods given in Appendix A are different formulations of the reserve energy approach. While these are developed for rocking in a cantilevered rigid body, the reserve energy approach is similar and reinforces the applicability of the ASCE/SEI 43-05 [4] criteria to the DOE/EH-0545 [1] capacity equation.

For the purposes of using the ASCE/SEI 43-05 [4] factor of safety with the DOE/EH-0545 [1]

rigid two body rocking capacity, the best-estimate of the capacity must be defined. As noted above, the reserve energy approach provides best-estimate of the capacity of the block wall, which Dr. Kennedy also agreed with. Therefore the DOE/EH-0545 [1] capacity calculation, without the -factor, can be utilized to determine the best-estimate capacity of the rigid two body rocking wall.

The development of the best-estimate capacity is only a portion of integrating the ASCE/SEI 43-05 [4] criteria into the DOE/EH-0545 [1] methodology; the allowable deformation capacity based on the factor of safety must also be established. The DOE/EH-0545 limits the out-of-plane displacement capacity at the crack location to 90% of the wall thickness, called the stability limit. By applying the ASCE/SEI 43-05 Factor of Safety [4], the out-of-plane displacement is limited to half the stability limit of the wall.

1.3 Sensitivity Study 2 - DOE/EH-0545 Methodology with Suggested Modifications In addition to the procedures outlined in DOE/EH-0545 [1], for a HCLPF calculation Dr. Kennedy suggests that uncertainty in wall response should be accounted for by shifting the calculated frequency of the block wall by +/- 15% and conservatively using the maximum response. This additional conservatism is not specifically incorporated in the DOE/EH-0545 methodology [1],

but it is consistent with the Conservative Deterministic Failure Margin (CDFM) approach of accounting for uncertainty in the structure frequency. The second HCLPF sensitivity study incorporated the use of the envelope seismic response associated with this frequency shifting.

1.4 Example Calculation Using Different Methodologies The example calculation below utilizes the properties of block walls EGB-272-6, 7, 9, and 10 from JAF. A more detailed evaluation of the block walls is contained in SGH Calculation No. 148115-CA-003 [3].

t = 11 5/8 in. Actual thickness of 12 in. concrete block b = 0.9t Effective wall thickness

= 0.9 * (11 5/8 in)

= 10.5 in.

H = 24.50 ft Wall height from base to bottom of roof beam SAP =

• 6 * [10.5 in / (24.5 ft

• 12 in/ft)] * [1 - H / (2

• 10.5 in)]

= * (0.21 - 0.01

• H)

Entergy - Project 148115.50 11 November 2014 Original SGH Calculation Utilizing DOE/EH-0545 See SGH Calculation 148115-CA-003 [3] for additional information.

H = 10.5 in. Use stability limit of the wall

= 0.67 SAP = 0.67 * (0.21 - 0.01

• 10.5 in)

= 0.07g fe = (1 / 2) [ (1.5

• 0.07 g

• 386.4 in/s2) / 10.5 in ]

= 0.31 Hz SAD = 0.09g SAP/SAD = 0.07g / 0.09g

= 0.78 HCLPF = 0.78

• 0.3g

= 0.23g Sensitivity Study 1 - DOE/EH-0545 Approach Utilizing ASCE/SEI 43-05 Overturning Factor of Safety H = 10.5 in / 2 Use 1/2 stability limit of the wall (FSR = 2.0)

= 5.25 in.

= 1.0 To develop best-estimate of capacity SAP = 1.0 * (0.21 - 0.01

• 5.25 in)

= 0.16g fe1 = 1.15 * (1 / 2) [ (1.5

• 0.16g

• 386.4 in/s2) / 5.25 in ]

= 0.77 Hz SAD = 0.23g SAP/SAD = 0.16g / 0.23g

= 0.70 HCLPF = 0.70

• 0.3g

= 0.21g 1

Also includes 15% frequency shift suggested by Dr. Kennedy.

Entergy - Project 148115.50 11 November 2014 Sensitivity Study 2 - DOE/EH-0545 Approach Utilizing 15% Frequency Shift H = 10.5 in. Use stability limit of the wall

= 0.67 SAP = 0.67 * (0.21 - 0.01

• 10.5 in)

= 0.07g fe = 1.15 * (1 / 2) [ (1.5

• 0.07 g

• 386.4 in/s2) / 10.5 in ]

= 0.36 Hz SAD = 0.10g SAP/SAD = 0.07g / 0.10g

= 0.68 HCLPF = 0.68

• 0.3g

= 0.20g The HCLPF determined from these three methodologies are all very close and demonstrate the bounds of the block wall HCLPF.

Table 1 HCLPF Summary Approach Approach HCLPF Original SGH Calculation DOE/EH-0545 0.23g Sensitivity Study 1 DOE/EH-0545 with ASCE/SEI 43-05 FS on Overturning 0.21g Sensitivity Study 2 DOE/EH-0545 with 15% Frequency Shift 0.20g 1.5 Effect on JAF IPEEE Screening As noted above, the sensitivity studies on the block wall HCLPF capacity result in a very tight range of values. The lower bound HCLPF of this range, 0.20g, is lower than the current plant level HCLPF of 0.22g. If we consider this lower bound estimate of the block wall HCLPF (0.20g) to represent the JAF plant HCLPF, the resulting overall plant IPEEE HCLPF Spectrum (IHS) would still exceed the JAF GMRS at all frequencies. Between the 1 Hz and 10 Hz range that is stipulated in the SPID [5] to define the boundaries with which to perform the NTTF 2.1 seismic screening, the IHS greatly exceeds the GMRS.

The plot below (Figure 1-1) shows the IHS (dotted line with 0.22g PGA HCLPF) and GMRS reported in the 31 March submittal. We have also plotted the IHS resulting from the two subsequent sensitivity studies to verify the assumptions included within this HCLPF calculation would not result in different screening decisions as part of the NTTF 2.1 assessments.

Regardless of the HCLPF evaluation procedure selected, the IHS still exceeds to the new JAF GMRS. Therefore the results of the HCLPF sensitivity studies serve to help validate the SPID screening results from the JAF 31 March submittal.

Entergy - Project 148115.50 11 November 2014 Figure 1 IHS and GMRS Reported in the 31 March Submittal

2. FRAGILITY EVALUATION DISCUSSION The USNRC also requested that SGH provide some insights on the safety factors between the calculation of the HCLPF for unreinforced block walls and the calculation of a median fragility level for the same block walls. A complete fragility calculation would be a significant effort and would involve a new assessment of the original IPEEE seismic response analyses that was conducted for these walls. As such, we did not develop a completely new fragility for these block walls but offer some general considerations on the two main elements of the fragility characterization: the seismic capacity and the seismic response.

2.1 Capacity Factor (Median / HCLPF)

The equation within DOE/EH-0545 [1] (and its supporting references) for the block wall spectral acceleration capacity represents the design capacity of the wall. This equation has a strength reduction factor () which was inserted to provide conservatism in the DOE/EH-0545 design process. As noted above the basic equation without this -factor represents the best estimate of the displaced shape at failure of the block wall. Thus, the factor between the HCLPF capacity and the median capacity level is a function of the effects of this applied -factor. To calculate the median, and remove the conservatism introduced in the design process, the median is calculated using the DOE/EH-0545 [1] procedures with the -factor set to 1.0.

Entergy - Project 148115.50 11 November 2014 Median Capacity

= 1.0 SAP = 1.0 * (0.21 - 0.01

• 10.5 in)

= 0.105g fe = (1 / 2) [ (1.5

• 0.11 g

• 386.4 in/s2) / 10.5 in ]

= 0.39 Hz SAD = 0.11g SAP/SAD = 0.105g / 0.11g

= 0.955 Am = 0.955

• 0.3g

= 0.29g This median results in a factor (median / HCLPF) on capacity of:

SFCAP = 0.29g / 0.23g

= 1.26 2.2 Response Factor (Median / HCLPF)

The median fragility is calculated by dividing the median capacity by the median demand.

Factors of conservatism are incorporated into the HCLPF methodology for both the seismic capacity elements and the seismic demand elements of the fragility. The seismic input used in the above HCLPF calculations is determined from the IPEEE SMA evaluation of JAF and is intended to represent input for a margin study and not a median centered fragility evaluation.

Therefore additional safety factors associated with response exist but cannot be readily calculated without a more exhaustive effort to reproduce median-centered in-structure response spectra (ISRS) and to research the basis for the original IPEEE seismic response. Therefore, to examine the factor on response, typical values for the median-to-HCLPF ratio are used as a point of comparison. Table 2-1 (Table 6-2, reproduced below, of the SPID (EPRI 102587) [5])

provides recommended values to relate the median capacity to a HCLPF capacity (C50% /C1%).

The block walls can be considered similar to a structure and are at low elevation, so the factor of 2.26 in the first row is an appropriate point of comparison. It should be noted, however, that the factor is expected to be lower than the stated 2.26 because the block wall essentially exhibits no inelastic energy absorption aside from the energy dissipation represented by 5%

damping. In addition, in the low frequency range where the effective wall frequencies have been estimated, there may be a less pronounced difference between a CDFM level response and a median-centered level response. This may also result in a lower safety factor on response.

Entergy - Project 148115.50 11 November 2014 EPRI NP-6041-SLR1 [2] defines the seismic response parameters typically included in a CDFM and would be required to be included in a fragility comparison:

• Structural damping

• Structural frequency

• Soil damping

• Soil-structure interaction

• Structure modeling

• Mode combination

• Seismic response analysis methods

• Earthquake component combination As noted above, a majority of these elements cannot be addressed without an appropriate re-evaluation of the demand. However, the one element we can address is uncertainty in the structural frequency. This was accomplished in the above sensitivity studies by incorporating a 15% shift in the calculated frequency of the block wall. The effect of this frequency shift is quantified by the difference between the HCLPF calculated in the original SGH calculation of 0.23g and the HCLPF calculated in the second sensitivity study of 0.20g. The frequency shift factor can be calculated as:

SFFreq = 0.23g / 0.20g

= 1.15 Combined with the factor on capacity noted above, 1.26, the resulting factor, considering only capacity and the demand shift in frequency, is:

SF = 1.26

• 1.15

= 1.45 Compared to the typical factor on median capacity to a HCLPF of 2.26, and recognizing this factor may be lower for an unreinforced block wall, it is feasible to assume that the remainder of the margin due to the response factor could be achieved by considering a more appropriate fragility-based demand.

Entergy - Project 148115.50 11 November 2014 Table 2 Recommended Values

3. REFERENCES

[1] United States Department of Energy, Seismic Evaluation Procedure for Equipment in the U.S Department of Energy Facilities, DOE/EH-0545, March 1997.

[2] Electric Power Research Institute, A Methodology for Assessment of Nuclear Power Plant Seismic Margin (Revision 1), EPRI NP-6041-SL, Revision 1, Palo Alto, CA, Aug. 1991.

[3] Simpson Gumpertz & Heger Inc., EGB Block Wall HCLPF Calculation, Calculation No. 148115-CA-003, Revision 0, Newport Beach, CA, 11 Aug. 2014.

[4] American Society of Civil Engineers, Seismic Design Criteria for Structures, Systems, and Components in Nuclear Facilities, ASCE/SEI 43-05, American Society of Civil Engineers, Reston, VA, 2005.

[5] Electric Power Research Institute, Seismic Evaluation Guidance Screening, Prioritization and Implementation Details (SPID) for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic, EPRI 1025287, Palo Alto, CA, 2013.

Sincerely yours, Greg S. Hardy Philip S. Hashimoto Timothy J. Graf Senior Principal Senior Principal Senior Staff - Structures I:\OC\Projects\2014\148115.50-JAFZ\WP\001GSHardy-L-148115.50.cc.docx

JAFP-14-0128 Attachment Regulatory Commitments (1 Page)

JAFP-14-0128 Attachment Regulatory Commitments This table identifies actions discussed in this letter for which Entergy commits to perform. Any other actions discussed in this submittal are described for the NRCs information and are not commitments.

TYPE (Check one) SCHEDULED ONE- COMPLETION CONTINUING COMMITMENT TIME DATE COMPLIANCE ACTION (If Required)

Perform a Relay Chatter Review to support On the schedule IPEEE focused scope margin assessment specified in the NEI per SPID in accordance with NEI letter, X Letter dated April 9, Relay Chatter Reviews for Seismic Hazard 2013 Screening, dated October 3, 2013 Page 1 of 1