ML15301A909

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NRR E-mail Capture - Brunswick Steam Electric Plant - Technical Review Checklist Related to Interim ESEP Supporting Implementation of NTTF R2.1, Seismic
ML15301A909
Person / Time
Site: Brunswick  Duke energy icon.png
Issue date: 10/23/2015
From: Diane Jackson
Office of New Reactors
To: Mohamed Shams
Japan Lessons-Learned Division
References
MF5228, MF5229
Download: ML15301A909 (12)
v • d • e


Text

NRR-PMDAPEm Resource From: Jackson, Diane Sent: Friday, October 23, 2015 3:21 PM To: Shams, Mohamed Cc: DiFrancesco, Nicholas; Wyman, Stephen; Spence, Jane; Devlin-Gill, Stephanie; Roche, Kevin; Yee, On; Rodriguez, Ricardo; Ng, Ching; Park, Sunwoo; Heeszel, David; 50.54f_Seismic Resource; RidsNroDsea Resource; Hsu, Kaihwa

Subject:

BRUNSWICK STEAM ELECTRIC PLANT - TECHNICAL REVIEW CHECKLIST RELATED TO INTERIM ESEP SUPPORTING IMPLEMENTATION OF NTTF R2.1, SEISMIC (TAC NOS.

MF5228 and MF5229)

Attachments: Brunswick R2 1 Seismic ESEP NRC review.docx October 23, 2015 MEMORANDUM TO: Mohamed K. Shams, Chief Hazards Management Branch (JHMB)

Japan Lessons-Learned Division Office of Nuclear Reactor Regulation FROM: Diane T. Jackson, Chief Geosciences and Geotechnical Engineering Branch 2 (RGS2)

Division of Site Safety and Environmental Analysis Office of New Reactors

SUBJECT:

BRUNSWICK STEAM ELECTRIC PLANT - TECHNICAL REVIEW CHECKLIST RELATED TO INTERIM EXPEDITED SEISMIC EVALUATION PROCESS SUPPORTING IMPLEMENTATION OF NTTF RECOMMENDATION 2.1, SEISMIC, RELATED TO THE FUKUSHIMA DAI-ICHI NUCLEAR POWER PLANT ACCIDENT (TAC NOS. MF5228 AND MF5229)

The NRC technical staff working through the Geosciences and Geotechnical Engineering Branches 1 and 2 (RGS1 and RGS2) completed the Technical Review Checklist of the BRUNSWICK STEAM ELECTRIC PLANT response to Enclosure 1, Item (6) of the March 12, 2012, request for information letter issued per Title 10 of the Code of Federal Regulations, Subpart 50.54(f), to power reactor licensees and holders of construction permits requesting addressees to provide further information to support the NRC staffs evaluation of regulatory actions to be taken in response to Fukushima Near-Term Task Force (NTTF) Recommendation 2.1:

Seismic which implements lessons learned from Japans March 11, 2011, Great Thoku Earthquake and subsequent tsunami. This addresses the staff review of the interim Expedited Seismic Evaluation Process (ESEP) report in response to Requested Item (6) of Enclosure 1, Recommendation 2.1: Seismic, of the 50.54(f) letter. Attached is a file containing the technical review checklist to prepare a response letter to the licensee.

The NRC staff reviewed the information provided and, as documented in the enclosed staff checklist, determined that sufficient information was provided to be responsive to this portion of the Enclosure 1 of the 50.54(f) letter. The application of this staff review is limited to the interim ESEP as part of NTTF R2.1: Seismic activities.

1

This electronic memo constitutes the DSEA concurrence provided that only editorial changes are made to the staff assessment that would not affect the technical conclusions or technical context of the assessment.

This concludes the NRCs efforts associated with TAC NO. MF5228 and MF5229 for the review of the interim ESEP report for the BRUNSWICK STEAM ELECTRIC PLANT.

Docket No: 50-325 and 50-324 CONTACT: Stephanie Devlin-Gill Office of New Reactors 301-415-5301 Copy: Nicholas DiFrancesco, Steve Wyman, Jane Spence, Stephanie Devlin-Gill, Kevin Roche, On Yee, Ricardo Rodriguez, Ching Ng, Sunwoo Park, Robert Hsu, David Heeszel, 50.54(f), RidsNroDsea_Resource 2

Hearing Identifier: NRR_PMDA Email Number: 2484 Mail Envelope Properties (e3ab5964bef64ac3a99cdc0563a45481)

Subject:

BRUNSWICK STEAM ELECTRIC PLANT - TECHNICAL REVIEW CHECKLIST RELATED TO INTERIM ESEP SUPPORTING IMPLEMENTATION OF NTTF R2.1, SEISMIC (TAC NOS.

MF5228 and MF5229)

Sent Date: 10/23/2015 3:21:19 PM Received Date: 10/23/2015 3:21:20 PM From: Jackson, Diane Created By: Diane.Jackson@nrc.gov Recipients:

"DiFrancesco, Nicholas" <Nicholas.DiFrancesco@nrc.gov>

Tracking Status: None "Wyman, Stephen" <Stephen.Wyman@nrc.gov>

Tracking Status: None "Spence, Jane" <Jane.Spence@nrc.gov>

Tracking Status: None "Devlin-Gill, Stephanie" <Stephanie.Devlin-Gill@nrc.gov>

Tracking Status: None "Roche, Kevin" <Kevin.Roche@nrc.gov>

Tracking Status: None "Yee, On" <On.Yee@nrc.gov>

Tracking Status: None "Rodriguez, Ricardo" <Ricardo.Rodriguez@nrc.gov>

Tracking Status: None "Ng, Ching" <Ching.Ng@nrc.gov>

Tracking Status: None "Park, Sunwoo" <Sunwoo.Park@nrc.gov>

Tracking Status: None "Heeszel, David" <David.Heeszel@nrc.gov>

Tracking Status: None "50.54f_Seismic Resource" <50.54f_Seismic.Resource@nrc.gov>

Tracking Status: None "RidsNroDsea Resource" <RidsNroDsea.Resource@nrc.gov>

Tracking Status: None "Hsu, Kaihwa" <Kaihwa.Hsu@nrc.gov>

Tracking Status: None "Shams, Mohamed" <Mohamed.Shams@nrc.gov>

Tracking Status: None Post Office: HQPWMSMRS07.nrc.gov Files Size Date & Time MESSAGE 2725 10/23/2015 3:21:20 PM Brunswick R2 1 Seismic ESEP NRC review.docx 52035 Options Priority: Standard Return Notification: No Reply Requested: No

Sensitivity: Normal Expiration Date:

Recipients Received:

TECHNICAL REVIEW CHECKLIST BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO EXPEDITED SEISMIC EVALUATION PROCESS INTERIM EVALUATION IMPLEMENTING NTTF RECOMMENDATION 2.1 SEISMIC BRUNSWICK STEAM ELECTRIC PLANT, UNITS 1 & 2 DOCKET NOS. 50-325 AND 50-324 By letter dated March 12, 2012 (USNRC, 2012a), the U.S. Nuclear Regulatory Commission (NRC) issued a request for information to all power reactor licensees and holders of construction permits in active or deferred status, pursuant to Title 10 of the Code of Federal Regulations (10 CFR), Section 50.54(f) Conditions of License (hereafter referred to as the 50.54(f) letter). Enclosure 1 of the 50.54(f) letter requests addressees to reevaluate the seismic hazard at their site using present-day methods and guidance for licensing new nuclear power plants, and identify actions to address or modify, as necessary, plant components affected with the reevaluated seismic hazards. Requested Information Item (6) in Enclosure 1 to the 50.54(f) letter requests addressees to provide an interim evaluation and actions taken or planned to address a higher seismic hazard relative to the design basis, as appropriate, prior to completion and submission of the seismic risk evaluation.

Additionally, by letter dated April 12, 20131, the Electric Power Research Institute (EPRI) staff submitted EPRI TR 3002000704 Seismic Evaluation Guidance: Augmented Approach for the Resolution of Fukushima Near-Term Task Force (NTTF) Recommendation 2.1: Seismic (hereafter referred to as the guidance). The Augmented Approach proposed that licensees would use an Expedited Seismic Evaluation Process (ESEP) to address the interim actions as requested by Information Item (6) in the 50.54(f) letter. The ESEP is a simplified seismic capacity evaluation with a focused scope of certain key installed Mitigating Strategies equipment that is used for core cooling and containment functions to cope with scenarios that involve a loss of all AC power and loss of access to the ultimate heat sink to withstand the Review Level Ground Motion, which is up to two times the safe shutdown earthquake (SSE).

Due to the expedited and interim nature of the ESEP, the assessment does not include many considerations that are part of a normal risk evaluation. These deferred items, include but are not limited to, structures, piping, non-seismic failures, and operator actions, as well scenarios such as addressing loss of coolant accidents. By letter dated May 7, 20132, the NRC staff endorsed the guidance. Central and eastern United States licensees with a reevaluated seismic hazard exceeding the SSE submitted an ESEP interim evaluation in December 2014 Consistent with the interim nature of this activity, the staff performed the review of the licensees submittal to assess whether the intent of the guidance was implemented. A multi-disciplined team checked whether the identified methods were consistent with the guidance. A senior expert panel reviewed the teams questions, if any, and checklist for consistency and scope.

New or updated parameters (e.g., In-Structure Response Spectra, High Confidence of Low Probability of Failure calculations) presented by the licensees were assessed only based on licensee statements for acceptability for the Item (6) response. The application of this staff review is limited to the ESEP interim evaluation as part of NTTF R2.1: Seismic activities.

1 ADAMS Accession No. ML13102A142 2 ADAMS Accession No. ML13106A331

NTTF Recommendation 2.1 Expedited Seismic Evaluation Process Technical Review Checklist for Brunswick Steam Electric Plant, Units 1 and 2 By letter dated December 18, 20143, Duke Energy (the licensee) provided an Expedited Seismic Evaluation Process (ESEP) report in a response to Enclosure 1, Requested Information Item (6) of the 50.54(f) letter, for the Brunswick Steam Electric Plant, Units 1 and 2 (BSEP).

I. Review Level Ground Motion The licensee:

  • described the determination of the review level ground motion Yes (RLGM) using one of the means acceptable by the guidance
  • identified location of the control point and is consistent with March Yes 2014 Seismic Hazard and Screening Report submittal 4
  • compared the site ground motion response spectra used to select Yes the ESEP RLGM to the SSE.

BSEP used a scaled SSE at a ratio of 2.0 Notes from the Reviewer:

  • The RLGM was scaled to the maximum ratio of 2.0 for the ESEP beause the ground motion response sprectrum (GMRS)-to-SSE ratio exceeds 2.0 in the March 2014 Seismic Hazard and Screening Report.

Deviation(s) or Deficiency(ies), and Resolution:

  • No deviations or deficiencies were identified The NRC staff concludes:
  • the licensees RLGM meets the intent of the guidance Yes
  • the RLGM is reasonable for use in the interim evaluation Yes II. Selection of the Success Path The licensee:
  • described the success path Yes
  • described normal and desired state of the equipment for the Yes success path
  • ensured that the success path is consistent with the plants overall Yes mitigating strategies approach or provided a justification for an alternate path
  • stated that the selection process was in accordance with the Yes guidance or meets the intent of the guidance
  • used installed FLEX Phase 1 equipment as part of the success Yes path Yes
  • included FLEX Phase 2 and/or 3 connections Yes
  • considered installed FLEX Phase 2 and/or 3 equipment Notes from the Reviewer: None Deviation(s) or Deficiency(ies), and Resolution:

NTTF Recommendation 2.1 Expedited Seismic Evaluation Process Technical Review Checklist for Brunswick Steam Electric Plant, Units 1 and 2 The NRC staff concludes that:

  • the selected success path is reasonable for use in the interim Yes evaluation
  • the licensee considered installed Phase 2 and 3 connections or Yes equipment in the interim evaluation.

III. Selection of the Equipment List The licensee:

  • developed and provided the ESEL by applying the ESEP Yes
  • identified equipment considering the following functions:

o Core cooling (with focus on Mode 1) function Yes o Available, sustainable water source Yes o Containment function and integrity Yes Notes from the Reviewer: None Deviation(s) or Deficiency(ies), and Resolution:

  • No deviations or deficiencies were identified For PWR Plants ONLY The licensee included indicators / instrumentation for the following functions: level, pressure, temperature, that would be indicative of (but not N/A explicitly identified to specific instruments): water level of the steam generator (SG), pressure of SG, containment, and reactor coolant system (RCS); and temperature of the RCS.

For BWR Plants ONLY The licensee considered indicators for the following functions:

level, pressure, temperature that would be indicative of (but not explicitly Yes identified to specific instruments): Temperature of suppression pool, RCS, containment); Pressure of suppression pool, RCS, and drywell; water level of the suppression pool.

Notes from the Reviewer: None Deviation(s) or Deficiency(ies), and Resolution:

  • No deviations or deficiencies were identified Through a sampling of the ESEP key components, the NRC staff concludes that:
  • the licensees process to develop the ESEL meets the intent of the Yes guidance for the interim evaluation
  • the desired equipment state for the success path were identified Yes
  • the licensee considered the support equipment for the ESEL Yes
  • both front-line and support systems appeared to be included in the Yes ESEL as evidenced by inclusion of SSCs on the success path and of support systems (e.g., batteries, motor control centers, inverters).

3

NTTF Recommendation 2.1 Expedited Seismic Evaluation Process Technical Review Checklist for Brunswick Steam Electric Plant, Units 1 and 2 IV. Walkdown Approach The licensee:

  • described the walkdown screening approach, including walkbys Yes and walkdowns performed exclusively for the ESEP, in accordance with the guidance
  • credited previous walkdown results, including a description of Yes current action(s) to verify the present equipment condition and/or configuration (e.g., walk-bys), in accordance with the guidance
  • stated that the walkdown was performed by seismically trained Yes personnel Notes from the Reviewer: None Deviation(s) or Deficiency(ies), and Resolution:
  • No deviations or deficiencies were identified The licensee:
  • described, if needed, adverse material condition of the equipment Yes (e.g. material degradation)
  • credited previous walkdown results, included a description of Yes current action(s) to verify the present equipment condition (e.g., walk-bys), meeting the intent of the guidance The licensee:
  • described the conditions of structural items considered for the interim evaluation, including:

o spatial interactions (i.e. interaction between block walls and Yes other items/components) o anchorage Yes o piping connected to tanks (i.e. differential movement Yes between pipes and tanks at connections)

Notes from the Reviewer: None Deviation(s) or Deficiency(ies), and Resolution:

  • No deviations or deficiencies were identified The licensee reported deviations for BSEP. No If deviations were identified, there is a discussion of how the deficiencies N/A were or will be addressed in the ESEP submittal report.

The NRC staff concludes that:

  • the licensee described the performed walkdown approach, Yes including any credited previous efforts (e.g., Individual Plant Examination of External Events, IPEEE) consistent with the guidance N/A
  • the licensee addressed identified deviations consistent with the guidance, if any 4

NTTF Recommendation 2.1 Expedited Seismic Evaluation Process Technical Review Checklist for Brunswick Steam Electric Plant, Units 1 and 2 V. Capacity Screening Approach and High Confidence/Low Probability of Failure (HCLPF) Calculation Results The licensee:

  • described the capacity screening process for the ESEL items, Yes consistent with the guidance (e.g., use of EPRI NP-6041 screening table).
  • presented the results of the screened-out ESEL items in the ESEP Yes report
  • described the development of in-structure response spectra (ISRS) Yes based on scaling
  • described the development of ISRS based on new analysis N/A consistent with the guidance
  • described the method for estimating HCLPF capacity of screened-in Yes ESEL items, including both structural and functional failure modes consistent with the guidance:

o use of Conservative Deterministic Failure Margin (CDFM) Yes o use of fragility analysis (FA) N/A o use of experience data or generic information N/A

  • credited IPEEE spectral shape for HCLPF capacity estimates is similar to or envelopes the RLGM, and anchored at the same No control point
  • presented the results of HCLPF capacities including associated Yes failure modes for screened-in ESEL items Yes
  • reviewed the ESEL items with the lowest HCLPF values to ensure that their capacities are equal or greater than the RLGM Notes from the Reviewer:
  • The staff requested clarification regarding the use of the A-46 spectra, instead of the SSE spectra, in developing the ESEP ISRS for the containment. To address this question, an audit was conducted to review the supporting documents provided by BSEP via an electronic reading room, as discussed in the NRC Audit Summary Report (ML15279A450). Based on the review of the BSEP Calculation BNP-13-05-600-001, the RLGM for the containment building was developed using two times the A-46 spectrum anchored to 0.16g. Furthermore, the calculation also demonstrates that, for the containment building, the ISRS were developed using two times the A-46 ISRS. The staff finds the use of two times the A-46 spectrum as the RLGM and two times the A-46 ISRS as the ESEP ISRS are acceptable for this interim evaluation.
  • The staff requested clarification regarding the HCLPF capacity for two of the items that were screened out. This question was addressed during the audit of the supporting documents provided via an electronic reading room as discussed in the NRC Audit Summary Report (ML15279A450). The two components were screened out from further review based on their seismic ruggedness. Therefore, BSEP concluded that it would be appropriate to assign a >RLGM in the HCPLF capacity column of the HCLPF table for these components. Based on a review of the 5

NTTF Recommendation 2.1 Expedited Seismic Evaluation Process Technical Review Checklist for Brunswick Steam Electric Plant, Units 1 and 2 documents, the staff finds that this approach is acceptable for this interim evaluation.

Deviation(s) or Deficiency(ies), and Resolution:

  • No deviations or deficiencies were identified The NRC staff concludes that:
  • the licensee described the implementation of the capacity screening Yes process consistent with the intent of the guidance
  • the licensee presented capacity screening and calculation results, Yes as appropriate, in the ESEP report
  • the method used to develop the ISRS is consistent with guidance for Yes use in the ESEP
  • for HCLPF calculations, the licensee used HCLPF calculation Yes methods as endorsed in the guidance
  • no anomalies were noted in the reported HCLPF Yes VI. Inaccessible Items The licensee:
  • provided a list of inaccessible items Yes
  • provided a schedule of the planned walkdown and evaluation for all N/A inaccessible items
  • provided Regulatory Commitment to complete walkdowns. N/A BSEP will complete walkdowns by: N/A.

Notes from the Reviewer:

  • In order to assess the current conditions of the inaccessible items, the staff requested clarification on the information (such as dates of photographs and inspections) used by the Seismic Review Team (SRT) to disposition the inaccessible items. The staff reviewed various documents provided by the licensee via an electronic reading room, as discussed in the NRC Audit Summary Report (ML15279A450). The staff reviewed a representative sample of the photographs, Seismic Evaluation Work Sheets (SEWS), and other information provided and finds that the licensee considered sufficient evidence in accordance with the intent of the guidance to make a determination regarding the current conditions of the inaccessible items. The staff finds this acceptable for this interim evaluation.

Deviation(s) or Deficiency(ies), and Resolution:

  • No deviations or deficiencies were identified The NRC staff concludes that the licensee:
  • listed inaccessible items Yes
  • committed to provide the results (e.g. walkdowns, walkbys, etc) of N/A the remaining inaccessible items consistent with the guidance
  • substitutions, if needed, were appropriately justified N/A 6

NTTF Recommendation 2.1 Expedited Seismic Evaluation Process Technical Review Checklist for Brunswick Steam Electric Plant, Units 1 and 2 VII. Modifications to Plant Equipment The licensee:

  • identified modifications for ESEL items necessary to achieve No HCLPF values that bound the RLGM (excluding mitigative strategies equipment (FLEX)), as specified in the guidance
  • provided a schedule to implement such modifications (if any), N/A consistent with the intent of the guidance
  • provided Regulatory Commitment to complete modifications N/A
  • provided Regulatory Commitment to report completion of N/A modifications.

The licensee will:

  • complete modifications by: N/A
  • report completion of modifications: N/A Notes from the Reviewer: None Deviation(s) or Deficiency(ies), and Resolution:
  • No deviations or deficiencies were identified The NRC staff concludes that the licensee:
  • identified plant modifications necessary to achieve the target N/A seismic capacity
  • provided a schedule to implement the modifications (if any) N/A consistent with the guidance VIII.

Conclusions:

The NRC staff assessed the licensees implementation of the ESEP guidance. Due to the interim applicability of the ESEP evaluations, use of the information for another application would require a separate NRC review and approval. Based on its review, the NRC staff concludes that the licensees implementation of the interim evaluation meets the intent of the guidance. The staff concludes that, through the implementation of the ESEP guidance, the licensee identified and evaluated the seismic capacity of certain key installed Mitigating Strategies equipment that is used for core cooling and containment functions to cope with scenarios that involve a loss of all AC power and loss of access to the ultimate heat sink to withstand a seismic event up to the Review Level Ground Motion (RLGM). In the case of BSEP, the RLGM was set at the maximum ratio of two times the SSE in accordance with the guidance. The staff did not identify deviations or exceptions taken from the guidance. The application of this staff review is limited to the ESEP interim evaluation as part of NTTF R2.1:

Seismic activities. As noted in the review checklist, the staff did not identify deviations or exceptions were taken from the guidance. The licensee found all equipment evaluated for the ESEP to have adequate capacity for the required demand. Therefore, no modification of equipment was required.

In summary, the licensee, by implementing the ESEP interim evaluation, has demonstrated additional assurance which supports continued plant safety while the longer-term seismic 7

NTTF Recommendation 2.1 Expedited Seismic Evaluation Process Technical Review Checklist for Brunswick Steam Electric Plant, Units 1 and 2 evaluation is completed to support regulatory decision making. The NRC staff concludes that the licensee responded appropriately to Enclosure 1, Item (6) of the 50.54(f) letter, dated March 12, 2012, for Brunswick Steam Electric Plant, Units 1 and 2.

Principle Contributors:

David Heeszel, On Yee, Ching Ng, Robert Hsu, Sunwoo Park, Ricardo E. Rodriguez, Joseph Braverman (NRC consultant) 8

NRR-PMDAPEm Resource From: Jackson, Diane Sent: Friday, October 23, 2015 3:21 PM To: Shams, Mohamed Cc: DiFrancesco, Nicholas; Wyman, Stephen; Spence, Jane; Devlin-Gill, Stephanie; Roche, Kevin; Yee, On; Rodriguez, Ricardo; Ng, Ching; Park, Sunwoo; Heeszel, David; 50.54f_Seismic Resource; RidsNroDsea Resource; Hsu, Kaihwa

Subject:

BRUNSWICK STEAM ELECTRIC PLANT - TECHNICAL REVIEW CHECKLIST RELATED TO INTERIM ESEP SUPPORTING IMPLEMENTATION OF NTTF R2.1, SEISMIC (TAC NOS.

MF5228 and MF5229)

Attachments: Brunswick R2 1 Seismic ESEP NRC review.docx October 23, 2015 MEMORANDUM TO: Mohamed K. Shams, Chief Hazards Management Branch (JHMB)

Japan Lessons-Learned Division Office of Nuclear Reactor Regulation FROM: Diane T. Jackson, Chief Geosciences and Geotechnical Engineering Branch 2 (RGS2)

Division of Site Safety and Environmental Analysis Office of New Reactors

SUBJECT:

BRUNSWICK STEAM ELECTRIC PLANT - TECHNICAL REVIEW CHECKLIST RELATED TO INTERIM EXPEDITED SEISMIC EVALUATION PROCESS SUPPORTING IMPLEMENTATION OF NTTF RECOMMENDATION 2.1, SEISMIC, RELATED TO THE FUKUSHIMA DAI-ICHI NUCLEAR POWER PLANT ACCIDENT (TAC NOS. MF5228 AND MF5229)

The NRC technical staff working through the Geosciences and Geotechnical Engineering Branches 1 and 2 (RGS1 and RGS2) completed the Technical Review Checklist of the BRUNSWICK STEAM ELECTRIC PLANT response to Enclosure 1, Item (6) of the March 12, 2012, request for information letter issued per Title 10 of the Code of Federal Regulations, Subpart 50.54(f), to power reactor licensees and holders of construction permits requesting addressees to provide further information to support the NRC staffs evaluation of regulatory actions to be taken in response to Fukushima Near-Term Task Force (NTTF) Recommendation 2.1:

Seismic which implements lessons learned from Japans March 11, 2011, Great Thoku Earthquake and subsequent tsunami. This addresses the staff review of the interim Expedited Seismic Evaluation Process (ESEP) report in response to Requested Item (6) of Enclosure 1, Recommendation 2.1: Seismic, of the 50.54(f) letter. Attached is a file containing the technical review checklist to prepare a response letter to the licensee.

The NRC staff reviewed the information provided and, as documented in the enclosed staff checklist, determined that sufficient information was provided to be responsive to this portion of the Enclosure 1 of the 50.54(f) letter. The application of this staff review is limited to the interim ESEP as part of NTTF R2.1: Seismic activities.

1

This electronic memo constitutes the DSEA concurrence provided that only editorial changes are made to the staff assessment that would not affect the technical conclusions or technical context of the assessment.

This concludes the NRCs efforts associated with TAC NO. MF5228 and MF5229 for the review of the interim ESEP report for the BRUNSWICK STEAM ELECTRIC PLANT.

Docket No: 50-325 and 50-324 CONTACT: Stephanie Devlin-Gill Office of New Reactors 301-415-5301 Copy: Nicholas DiFrancesco, Steve Wyman, Jane Spence, Stephanie Devlin-Gill, Kevin Roche, On Yee, Ricardo Rodriguez, Ching Ng, Sunwoo Park, Robert Hsu, David Heeszel, 50.54(f), RidsNroDsea_Resource 2

Hearing Identifier: NRR_PMDA Email Number: 2484 Mail Envelope Properties (e3ab5964bef64ac3a99cdc0563a45481)

Subject:

BRUNSWICK STEAM ELECTRIC PLANT - TECHNICAL REVIEW CHECKLIST RELATED TO INTERIM ESEP SUPPORTING IMPLEMENTATION OF NTTF R2.1, SEISMIC (TAC NOS.

MF5228 and MF5229)

Sent Date: 10/23/2015 3:21:19 PM Received Date: 10/23/2015 3:21:20 PM From: Jackson, Diane Created By: Diane.Jackson@nrc.gov Recipients:

"DiFrancesco, Nicholas" <Nicholas.DiFrancesco@nrc.gov>

Tracking Status: None "Wyman, Stephen" <Stephen.Wyman@nrc.gov>

Tracking Status: None "Spence, Jane" <Jane.Spence@nrc.gov>

Tracking Status: None "Devlin-Gill, Stephanie" <Stephanie.Devlin-Gill@nrc.gov>

Tracking Status: None "Roche, Kevin" <Kevin.Roche@nrc.gov>

Tracking Status: None "Yee, On" <On.Yee@nrc.gov>

Tracking Status: None "Rodriguez, Ricardo" <Ricardo.Rodriguez@nrc.gov>

Tracking Status: None "Ng, Ching" <Ching.Ng@nrc.gov>

Tracking Status: None "Park, Sunwoo" <Sunwoo.Park@nrc.gov>

Tracking Status: None "Heeszel, David" <David.Heeszel@nrc.gov>

Tracking Status: None "50.54f_Seismic Resource" <50.54f_Seismic.Resource@nrc.gov>

Tracking Status: None "RidsNroDsea Resource" <RidsNroDsea.Resource@nrc.gov>

Tracking Status: None "Hsu, Kaihwa" <Kaihwa.Hsu@nrc.gov>

Tracking Status: None "Shams, Mohamed" <Mohamed.Shams@nrc.gov>

Tracking Status: None Post Office: HQPWMSMRS07.nrc.gov Files Size Date & Time MESSAGE 2725 10/23/2015 3:21:20 PM Brunswick R2 1 Seismic ESEP NRC review.docx 52035 Options Priority: Standard Return Notification: No Reply Requested: No

Sensitivity: Normal Expiration Date:

Recipients Received:

TECHNICAL REVIEW CHECKLIST BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO EXPEDITED SEISMIC EVALUATION PROCESS INTERIM EVALUATION IMPLEMENTING NTTF RECOMMENDATION 2.1 SEISMIC BRUNSWICK STEAM ELECTRIC PLANT, UNITS 1 & 2 DOCKET NOS. 50-325 AND 50-324 By letter dated March 12, 2012 (USNRC, 2012a), the U.S. Nuclear Regulatory Commission (NRC) issued a request for information to all power reactor licensees and holders of construction permits in active or deferred status, pursuant to Title 10 of the Code of Federal Regulations (10 CFR), Section 50.54(f) Conditions of License (hereafter referred to as the 50.54(f) letter). Enclosure 1 of the 50.54(f) letter requests addressees to reevaluate the seismic hazard at their site using present-day methods and guidance for licensing new nuclear power plants, and identify actions to address or modify, as necessary, plant components affected with the reevaluated seismic hazards. Requested Information Item (6) in Enclosure 1 to the 50.54(f) letter requests addressees to provide an interim evaluation and actions taken or planned to address a higher seismic hazard relative to the design basis, as appropriate, prior to completion and submission of the seismic risk evaluation.

Additionally, by letter dated April 12, 20131, the Electric Power Research Institute (EPRI) staff submitted EPRI TR 3002000704 Seismic Evaluation Guidance: Augmented Approach for the Resolution of Fukushima Near-Term Task Force (NTTF) Recommendation 2.1: Seismic (hereafter referred to as the guidance). The Augmented Approach proposed that licensees would use an Expedited Seismic Evaluation Process (ESEP) to address the interim actions as requested by Information Item (6) in the 50.54(f) letter. The ESEP is a simplified seismic capacity evaluation with a focused scope of certain key installed Mitigating Strategies equipment that is used for core cooling and containment functions to cope with scenarios that involve a loss of all AC power and loss of access to the ultimate heat sink to withstand the Review Level Ground Motion, which is up to two times the safe shutdown earthquake (SSE).

Due to the expedited and interim nature of the ESEP, the assessment does not include many considerations that are part of a normal risk evaluation. These deferred items, include but are not limited to, structures, piping, non-seismic failures, and operator actions, as well scenarios such as addressing loss of coolant accidents. By letter dated May 7, 20132, the NRC staff endorsed the guidance. Central and eastern United States licensees with a reevaluated seismic hazard exceeding the SSE submitted an ESEP interim evaluation in December 2014 Consistent with the interim nature of this activity, the staff performed the review of the licensees submittal to assess whether the intent of the guidance was implemented. A multi-disciplined team checked whether the identified methods were consistent with the guidance. A senior expert panel reviewed the teams questions, if any, and checklist for consistency and scope.

New or updated parameters (e.g., In-Structure Response Spectra, High Confidence of Low Probability of Failure calculations) presented by the licensees were assessed only based on licensee statements for acceptability for the Item (6) response. The application of this staff review is limited to the ESEP interim evaluation as part of NTTF R2.1: Seismic activities.

1 ADAMS Accession No. ML13102A142 2 ADAMS Accession No. ML13106A331

NTTF Recommendation 2.1 Expedited Seismic Evaluation Process Technical Review Checklist for Brunswick Steam Electric Plant, Units 1 and 2 By letter dated December 18, 20143, Duke Energy (the licensee) provided an Expedited Seismic Evaluation Process (ESEP) report in a response to Enclosure 1, Requested Information Item (6) of the 50.54(f) letter, for the Brunswick Steam Electric Plant, Units 1 and 2 (BSEP).

I. Review Level Ground Motion The licensee:

  • described the determination of the review level ground motion Yes (RLGM) using one of the means acceptable by the guidance
  • identified location of the control point and is consistent with March Yes 2014 Seismic Hazard and Screening Report submittal 4
  • compared the site ground motion response spectra used to select Yes the ESEP RLGM to the SSE.

BSEP used a scaled SSE at a ratio of 2.0 Notes from the Reviewer:

  • The RLGM was scaled to the maximum ratio of 2.0 for the ESEP beause the ground motion response sprectrum (GMRS)-to-SSE ratio exceeds 2.0 in the March 2014 Seismic Hazard and Screening Report.

Deviation(s) or Deficiency(ies), and Resolution:

  • No deviations or deficiencies were identified The NRC staff concludes:
  • the licensees RLGM meets the intent of the guidance Yes
  • the RLGM is reasonable for use in the interim evaluation Yes II. Selection of the Success Path The licensee:
  • described the success path Yes
  • described normal and desired state of the equipment for the Yes success path
  • ensured that the success path is consistent with the plants overall Yes mitigating strategies approach or provided a justification for an alternate path
  • stated that the selection process was in accordance with the Yes guidance or meets the intent of the guidance
  • used installed FLEX Phase 1 equipment as part of the success Yes path Yes
  • included FLEX Phase 2 and/or 3 connections Yes
  • considered installed FLEX Phase 2 and/or 3 equipment Notes from the Reviewer: None Deviation(s) or Deficiency(ies), and Resolution:

NTTF Recommendation 2.1 Expedited Seismic Evaluation Process Technical Review Checklist for Brunswick Steam Electric Plant, Units 1 and 2 The NRC staff concludes that:

  • the selected success path is reasonable for use in the interim Yes evaluation
  • the licensee considered installed Phase 2 and 3 connections or Yes equipment in the interim evaluation.

III. Selection of the Equipment List The licensee:

  • developed and provided the ESEL by applying the ESEP Yes
  • identified equipment considering the following functions:

o Core cooling (with focus on Mode 1) function Yes o Available, sustainable water source Yes o Containment function and integrity Yes Notes from the Reviewer: None Deviation(s) or Deficiency(ies), and Resolution:

  • No deviations or deficiencies were identified For PWR Plants ONLY The licensee included indicators / instrumentation for the following functions: level, pressure, temperature, that would be indicative of (but not N/A explicitly identified to specific instruments): water level of the steam generator (SG), pressure of SG, containment, and reactor coolant system (RCS); and temperature of the RCS.

For BWR Plants ONLY The licensee considered indicators for the following functions:

level, pressure, temperature that would be indicative of (but not explicitly Yes identified to specific instruments): Temperature of suppression pool, RCS, containment); Pressure of suppression pool, RCS, and drywell; water level of the suppression pool.

Notes from the Reviewer: None Deviation(s) or Deficiency(ies), and Resolution:

  • No deviations or deficiencies were identified Through a sampling of the ESEP key components, the NRC staff concludes that:
  • the licensees process to develop the ESEL meets the intent of the Yes guidance for the interim evaluation
  • the desired equipment state for the success path were identified Yes
  • the licensee considered the support equipment for the ESEL Yes
  • both front-line and support systems appeared to be included in the Yes ESEL as evidenced by inclusion of SSCs on the success path and of support systems (e.g., batteries, motor control centers, inverters).

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NTTF Recommendation 2.1 Expedited Seismic Evaluation Process Technical Review Checklist for Brunswick Steam Electric Plant, Units 1 and 2 IV. Walkdown Approach The licensee:

  • described the walkdown screening approach, including walkbys Yes and walkdowns performed exclusively for the ESEP, in accordance with the guidance
  • credited previous walkdown results, including a description of Yes current action(s) to verify the present equipment condition and/or configuration (e.g., walk-bys), in accordance with the guidance
  • stated that the walkdown was performed by seismically trained Yes personnel Notes from the Reviewer: None Deviation(s) or Deficiency(ies), and Resolution:
  • No deviations or deficiencies were identified The licensee:
  • described, if needed, adverse material condition of the equipment Yes (e.g. material degradation)
  • credited previous walkdown results, included a description of Yes current action(s) to verify the present equipment condition (e.g., walk-bys), meeting the intent of the guidance The licensee:
  • described the conditions of structural items considered for the interim evaluation, including:

o spatial interactions (i.e. interaction between block walls and Yes other items/components) o anchorage Yes o piping connected to tanks (i.e. differential movement Yes between pipes and tanks at connections)

Notes from the Reviewer: None Deviation(s) or Deficiency(ies), and Resolution:

  • No deviations or deficiencies were identified The licensee reported deviations for BSEP. No If deviations were identified, there is a discussion of how the deficiencies N/A were or will be addressed in the ESEP submittal report.

The NRC staff concludes that:

  • the licensee described the performed walkdown approach, Yes including any credited previous efforts (e.g., Individual Plant Examination of External Events, IPEEE) consistent with the guidance N/A
  • the licensee addressed identified deviations consistent with the guidance, if any 4

NTTF Recommendation 2.1 Expedited Seismic Evaluation Process Technical Review Checklist for Brunswick Steam Electric Plant, Units 1 and 2 V. Capacity Screening Approach and High Confidence/Low Probability of Failure (HCLPF) Calculation Results The licensee:

  • described the capacity screening process for the ESEL items, Yes consistent with the guidance (e.g., use of EPRI NP-6041 screening table).
  • presented the results of the screened-out ESEL items in the ESEP Yes report
  • described the development of in-structure response spectra (ISRS) Yes based on scaling
  • described the development of ISRS based on new analysis N/A consistent with the guidance
  • described the method for estimating HCLPF capacity of screened-in Yes ESEL items, including both structural and functional failure modes consistent with the guidance:

o use of Conservative Deterministic Failure Margin (CDFM) Yes o use of fragility analysis (FA) N/A o use of experience data or generic information N/A

  • credited IPEEE spectral shape for HCLPF capacity estimates is similar to or envelopes the RLGM, and anchored at the same No control point
  • presented the results of HCLPF capacities including associated Yes failure modes for screened-in ESEL items Yes
  • reviewed the ESEL items with the lowest HCLPF values to ensure that their capacities are equal or greater than the RLGM Notes from the Reviewer:
  • The staff requested clarification regarding the use of the A-46 spectra, instead of the SSE spectra, in developing the ESEP ISRS for the containment. To address this question, an audit was conducted to review the supporting documents provided by BSEP via an electronic reading room, as discussed in the NRC Audit Summary Report (ML15279A450). Based on the review of the BSEP Calculation BNP-13-05-600-001, the RLGM for the containment building was developed using two times the A-46 spectrum anchored to 0.16g. Furthermore, the calculation also demonstrates that, for the containment building, the ISRS were developed using two times the A-46 ISRS. The staff finds the use of two times the A-46 spectrum as the RLGM and two times the A-46 ISRS as the ESEP ISRS are acceptable for this interim evaluation.
  • The staff requested clarification regarding the HCLPF capacity for two of the items that were screened out. This question was addressed during the audit of the supporting documents provided via an electronic reading room as discussed in the NRC Audit Summary Report (ML15279A450). The two components were screened out from further review based on their seismic ruggedness. Therefore, BSEP concluded that it would be appropriate to assign a >RLGM in the HCPLF capacity column of the HCLPF table for these components. Based on a review of the 5

NTTF Recommendation 2.1 Expedited Seismic Evaluation Process Technical Review Checklist for Brunswick Steam Electric Plant, Units 1 and 2 documents, the staff finds that this approach is acceptable for this interim evaluation.

Deviation(s) or Deficiency(ies), and Resolution:

  • No deviations or deficiencies were identified The NRC staff concludes that:
  • the licensee described the implementation of the capacity screening Yes process consistent with the intent of the guidance
  • the licensee presented capacity screening and calculation results, Yes as appropriate, in the ESEP report
  • the method used to develop the ISRS is consistent with guidance for Yes use in the ESEP
  • for HCLPF calculations, the licensee used HCLPF calculation Yes methods as endorsed in the guidance
  • no anomalies were noted in the reported HCLPF Yes VI. Inaccessible Items The licensee:
  • provided a list of inaccessible items Yes
  • provided a schedule of the planned walkdown and evaluation for all N/A inaccessible items
  • provided Regulatory Commitment to complete walkdowns. N/A BSEP will complete walkdowns by: N/A.

Notes from the Reviewer:

  • In order to assess the current conditions of the inaccessible items, the staff requested clarification on the information (such as dates of photographs and inspections) used by the Seismic Review Team (SRT) to disposition the inaccessible items. The staff reviewed various documents provided by the licensee via an electronic reading room, as discussed in the NRC Audit Summary Report (ML15279A450). The staff reviewed a representative sample of the photographs, Seismic Evaluation Work Sheets (SEWS), and other information provided and finds that the licensee considered sufficient evidence in accordance with the intent of the guidance to make a determination regarding the current conditions of the inaccessible items. The staff finds this acceptable for this interim evaluation.

Deviation(s) or Deficiency(ies), and Resolution:

  • No deviations or deficiencies were identified The NRC staff concludes that the licensee:
  • listed inaccessible items Yes
  • committed to provide the results (e.g. walkdowns, walkbys, etc) of N/A the remaining inaccessible items consistent with the guidance
  • substitutions, if needed, were appropriately justified N/A 6

NTTF Recommendation 2.1 Expedited Seismic Evaluation Process Technical Review Checklist for Brunswick Steam Electric Plant, Units 1 and 2 VII. Modifications to Plant Equipment The licensee:

  • identified modifications for ESEL items necessary to achieve No HCLPF values that bound the RLGM (excluding mitigative strategies equipment (FLEX)), as specified in the guidance
  • provided a schedule to implement such modifications (if any), N/A consistent with the intent of the guidance
  • provided Regulatory Commitment to complete modifications N/A
  • provided Regulatory Commitment to report completion of N/A modifications.

The licensee will:

  • complete modifications by: N/A
  • report completion of modifications: N/A Notes from the Reviewer: None Deviation(s) or Deficiency(ies), and Resolution:
  • No deviations or deficiencies were identified The NRC staff concludes that the licensee:
  • identified plant modifications necessary to achieve the target N/A seismic capacity
  • provided a schedule to implement the modifications (if any) N/A consistent with the guidance VIII.

Conclusions:

The NRC staff assessed the licensees implementation of the ESEP guidance. Due to the interim applicability of the ESEP evaluations, use of the information for another application would require a separate NRC review and approval. Based on its review, the NRC staff concludes that the licensees implementation of the interim evaluation meets the intent of the guidance. The staff concludes that, through the implementation of the ESEP guidance, the licensee identified and evaluated the seismic capacity of certain key installed Mitigating Strategies equipment that is used for core cooling and containment functions to cope with scenarios that involve a loss of all AC power and loss of access to the ultimate heat sink to withstand a seismic event up to the Review Level Ground Motion (RLGM). In the case of BSEP, the RLGM was set at the maximum ratio of two times the SSE in accordance with the guidance. The staff did not identify deviations or exceptions taken from the guidance. The application of this staff review is limited to the ESEP interim evaluation as part of NTTF R2.1:

Seismic activities. As noted in the review checklist, the staff did not identify deviations or exceptions were taken from the guidance. The licensee found all equipment evaluated for the ESEP to have adequate capacity for the required demand. Therefore, no modification of equipment was required.

In summary, the licensee, by implementing the ESEP interim evaluation, has demonstrated additional assurance which supports continued plant safety while the longer-term seismic 7

NTTF Recommendation 2.1 Expedited Seismic Evaluation Process Technical Review Checklist for Brunswick Steam Electric Plant, Units 1 and 2 evaluation is completed to support regulatory decision making. The NRC staff concludes that the licensee responded appropriately to Enclosure 1, Item (6) of the 50.54(f) letter, dated March 12, 2012, for Brunswick Steam Electric Plant, Units 1 and 2.

Principle Contributors:

David Heeszel, On Yee, Ching Ng, Robert Hsu, Sunwoo Park, Ricardo E. Rodriguez, Joseph Braverman (NRC consultant) 8

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