ML15272A421

NRR E-mail Capture - Monticello Nuclear Station, Unit 1 - Technical Review Checklist Related to Interim ESEP Supporting Implementation of NTTF R2.1, Seismic

ML15272A421
Person / Time
Site:	Monticello
Issue date:	09/04/2015
From:	Diane Jackson Office of New Reactors
To:	Mohamed Shams Japan Lessons-Learned Division
References
TAC MF5251
Download: ML15272A421 (12)

Text

NRR-PMDAPEm Resource From: Jackson, Diane Sent: Friday, September 04, 2015 11:46 AM To: Shams, Mohamed Cc: DiFrancesco, Nicholas; Spence, Jane; Devlin-Gill, Stephanie; Roche, Kevin; Yee, On; Candelario, Luissette; Nakanishi, Tony; Lehman, Bryce; Tsirigotis, Alexander; 50.54f_Seismic Resource; RidsNroDsea Resource; Wyman, Stephen

Subject:

MONTICELLO NUCLEAR STATION, UNIT 1 - TECHNICAL REVIEW CHECKLIST RELATED TO INTERIM ESEP SUPPORTING IMPLEMENTATION OF NTTF R2.1, SEISMIC (TAC NO.

MF5251)

Attachments: Monticello R.2 1 Seismic ESEP NRC Review.docx September 4, 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:

MONTICELLO NUCLEAR STATION - 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 NO. MF5251)

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 MONTICELLO NUCLEAR STATION 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.

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. MF5251 for the review of the interim ESEP report for the MONTICELLO NUCLEAR STATION.

Docket No: 50-263 CONTACT: Stephanie Devlin-Gill Office of New Reactors 301-415-5301 1

Copy: Nicholas DiFrancesco, Steve Wyman, Jane Spence, Stephanie Devlin-Gill, Kevin Roche, On Yee, Luissette Candelario, Tony Nakanishi, Bryce Lehman, Alexander Tsirigotis, 50.54(f) Seismic Resource, RidsNroDsea Resource 2

Hearing Identifier: NRR_PMDA Email Number: 2417 Mail Envelope Properties (def0e779ffa646ce88ccc25641c31fe5)

Subject:

MONTICELLO NUCLEAR STATION, UNIT 1 - TECHNICAL REVIEW CHECKLIST RELATED TO INTERIM ESEP SUPPORTING IMPLEMENTATION OF NTTF R2.1, SEISMIC (TAC NO. MF5251)

Sent Date: 9/4/2015 11:46:24 AM Received Date: 9/4/2015 11:46:28 AM From: Jackson, Diane Created By: Diane.Jackson@nrc.gov Recipients:

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

Tracking Status: None "Nakanishi, Tony" <Tony.Nakanishi@nrc.gov>

Tracking Status: None "Lehman, Bryce" <Bryce.Lehman@nrc.gov>

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

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

Tracking Status: None Post Office: R4PWMSMRS03.nrc.gov Files Size Date & Time MESSAGE 3017 9/4/2015 11:46:28 AM Monticello R.2 1 Seismic ESEP NRC Review.docx 56138 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 MONTICELLO NUCLEAR GENERATING PLANT, UNIT 1 DOCKET NO. 50-263 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 Monticello Nuclear Generating Plant By letter dated December 23, 20143, Northern States Power Company, a Minnesota corporationdoing business as Xcel 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 Monticello Nuclear Generating Plant (Monticello).

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 submittal

• compared the site ground motion response spectra used to select the Yes ESEP RLGM to the SSE.

Monticelloused a scaled SSE at a ratio of 1.49 Notes from the Reviewer: None 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 success Yes path

• ensured that the success path is consistent with the plants overall Yes mitigating strategies approach or provided a justification for an alternate path Yes

• stated that the selection process was in accordance with the guidance or meets the intent of the guidance Yes

• used installed FLEX Phase 1 equipment as part of the success path

• included FLEX Phase 2 and/or 3 connections Yes

• considered installed FLEX Phase 2 and/or 3 equipment Yes Notes from the Reviewer: None Deviation(s) or Deficiency(ies), and Resolution:

No deviations or deficiencies were identified.

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.

3 ADAMS Accession No. ML14357A280 2

NTTF Recommendation 2.1 Expedited Seismic Evaluation Process Technical Review Checklist for Monticello Nuclear Generating Plant 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(1) Yes o Available, sustainable water source Yes o Containment function and integrity Yes Notes from the Reviewer:

1. The staff asked a question to the licensee regarding updates to the ESEL with the operating state for components that contains no information and the inclusion of certain components in the ESEP evaluation scope. The staff finds that the licensee responses (ML15142A862) adequately addressed the concern and met the intent of the guidance for this interim evaluation.

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 N/A not 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 ESEL as evidenced by inclusion of SSCs on the success path and Yes of support systems (e.g., batteries, motor control centers, inverters).

3

NTTF Recommendation 2.1 Expedited Seismic Evaluation Process Technical Review Checklist for Monticello Nuclear Generating Plant 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 deviation or deficiencies were identified.

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

• the licensee addressed identified deviations consistent with the guidance, if any 4

NTTF Recommendation 2.1 Expedited Seismic Evaluation Process Technical Review Checklist for Monticello Nuclear Generating Plant 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) Yes

• presented the results of the screened-out ESEL items in the ESEP 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- Yes in 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 Yes

• credited IPEEE spectral shape for HCLPF capacity estimates is similar to or envelopes the RLGM, and anchored at the same N/A control point

• presented the results of HCLPF capacities including associated failure modes for screened-in ESEL items Yes

• reviewed the ESEL items with the lowest HCLPF values to ensure Yes that their capacities are equal or greater than the RLGM (1)

Notes from the Reviewer:

• The staff requested clarification regarding the functional HCLPF capacity of certain relays and switches. The licensees responses (ML15142A862 and ML15225A463) shows that instead of using in-cabinet amplification factors to determine the seismic demand of relays, in-cabinet response spectra was used according to the screening procedure in EPRI NP-7148, which allows using the EPRI NP-7146 calculation methodology that utilizes the GENRS computer program. This calculation methodology and the GENRS software was also used in the USI-46 program and accepted by the NRC staff SSER No. 2 of the Generic Implementation Procedure (GIP) for seismic verification of nuclear plant equipment. Based on this, the use of the calculation methodology and the GENRS software for the Monticello ESEP is judged by the staff to be acceptable for this interim evaluation only and, therefore, the staff finds that the licensees response in conjunction with supplemental information (ML15142A862 and ML15225A463; respectively) adequately addressed the staffs concern. Other use and the implementation of GENRS for another application would require staff review.

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

No deviation or deficiencies were identified.

The NRC staff concludes that:

• the licensee described the implementation of the capacity Yes screening process consistent with the intent of the guidance

• the licensee presented capacity screening and calculation results, Yes as appropriate, in the ESEP report 5

NTTF Recommendation 2.1 Expedited Seismic Evaluation Process Technical Review Checklist for Monticello Nuclear Generating Plant

• the method used to develop the ISRS is consistent with guidance Yes for 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 No (see note above)

VI. Inaccessible Items The licensee:

• provided a list of inaccessible items (1) Yes

• provided a schedule of the planned walkdown and evaluation for all N/A inaccessible items

• provided Regulatory Commitment to complete walkdowns N/A Monticello will provide results or complete walkdown by: N/A N/A Notes from the Reviewer:

1. In response to a staff clarification request regarding the disposition of several inaccessible items, the licensee clarified in their responses dated May 22, 2015 (ML15142A862) and August 13,2015 (ML15225A463) that it relied on the results of R2.3 walkdowns and area walk-bys, performed comparisons with identical items and used alternative methods in accordance with NP-6041 to determine acceptability without a new walkdown. The staff finds that the licensee responsesadequately addressed the concern and is acceptable for the purposes of this interim evaluation.

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

No deviation 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 VII. Modifications The licensee:

• identified modifications for ESEL items necessary to achieve HCLPF Yes values that bound the RLGM (excluding mitigative strategies equipment (FLEX)), as specified in the guidance

• provided a schedule to implement such modifications (if any), Yes (1) consistent with the intent of the guidance

• provided Regulatory Commitment to complete modifications(1) Yes

• provided Regulatory Commitment to report completion of modifications. (1) Yes Monticello will:

• complete modifications by December 2016 for plant modifications not requiring a planned refueling outage, and prior to the end of the 2017 refueling outage for modifications requiring a refueling outage.

• report completion of modifications by: 60 days following completion of the ESEP activities.

6

NTTF Recommendation 2.1 Expedited Seismic Evaluation Process Technical Review Checklist for Monticello Nuclear Generating Plant Notes from the Reviewer:

1. The staff requested clarification regarding the schedule and status of resolutions, the methods employed, implementation and regulatory commitments for modifications, if required, onseveral components that have a HCLPF capacity less than the RLGM.In their response dated May 22, 2015 (ML15142A862), the licensee provided additional information regarding the applicable components. The licensee stated that resolutions will be completed by 12/31/2016 unless a plant outage is needed to implement a modification. In that case, the outage modification will be completed prior to the end of the 2017 refueling outage. The licensee committed to provide a letter indicating the proposed resolution applicable to each component and the expected timeframe for completion of the resolution when this information has been developed. Finally, the licensee committed to provide a letter summarizing the HCLPF results of each component and confirming the resolution of each component within 60 days of completion of the resolution activities for the final completed component from Table 7-1 of the RAI response. During a clarification call, on August 6, 2015, the licensee stated its expectation fora resolution path for each component that does not have sufficient capacity to withstand the RLGM, by the end of March 2016. The staff finds that the licensee response, in conjunction with the additional information provided during the clarification call,adequately addressed the concern and met the intent of the guidance for this interim evaluation.

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

No deviation or deficiencies were identified.

The NRC staff concludes that the licensee:

• identified plant modifications necessary to achieve the target seismic Yes capacity

• provided a schedule to implement the modifications (if any) Yes 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), and thus, provides additional assurance while the plant seismic risk evaluation is being conducted. In the case of Monticello, in accordance with the guidance, the RLGM used a scaled SSE at the ratio of 1.49.

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 identified safety enhancing modifications based on the evaluation and committed to complete modifications by December 31, 2016, unless a plant outage is needed to implement a modification. In that case, the licensee committed to complete it prior to the end of its2017 planned refueling outage. The licensee committed toprovide a letter summarizing the results and confirming the completion of modifications within 60days following completion of ESEP activities.

7

NTTF Recommendation 2.1 Expedited Seismic Evaluation Process Technical Review Checklist for Monticello Nuclear Generating Plant In summary, the licensee, by implementing the ESEP interim evaluation, has demonstrated additional assurance which supports continued plant safety while the longer-term seismic 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 Monticello Nuclear Generating Plant.

Principle Contributors:

Stephanie Devlin-Gill, Kevin Roche, Tony Nakanishi, Bryce Lehman, Alexander Tsirigotis, Luissette Candelario, Richard Morante (NRC consultant) 8