ML15272A420

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

ML15272A420
Person / Time
Site:	Summer
Issue date:	09/02/2015
From:	Diane Jackson Office of New Reactors
To:	Mohamed Shams Japan Lessons-Learned Division
References
TAC MF5269
Download: ML15272A420 (12)

Text

NRR-PMDAPEm Resource From: Jackson, Diane Sent: Wednesday, September 02, 2015 5:47 PM To: Shams, Mohamed Cc: DiFrancesco, Nicholas; Spence, Jane; Devlin-Gill, Stephanie; Roche, Kevin; Yee, On; Wang, Weijun; Gallucci, Ray; Patel, Pravin; Wyman, Stephen; Graizer, Vladimir; Pettis, Robert; 50.54f_Seismic Resource; RidsNroDsea Resource

Subject:

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

MF5269)

Attachments: VC Summer R2.1 Seismic ESEP NRC review.docx September 2, 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:

VC SUMMER NUCLEAR STATION, UNIT 1 - 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. MF5269)

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 VC SUMMER NUCLEAR STATION, UNIT 1 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. MF5269 for the review of the interim ESEP report for the VC SUMMER NUCLEAR STATION, UNIT 1.

Docket No: 50-395 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, Weijun Wang, Ray Gallucci, Pravin Patel, Bob Pettis, Vladimir Graizer, 50.54f Seismic Resource, RidsNroDsea Resource 2

Hearing Identifier: NRR_PMDA Email Number: 2416 Mail Envelope Properties (c77cfca2e76b40388f9e2f1f6a2ae20d)

Subject:

VC SUMMER NUCLEAR STATION, UNIT 1 - TECHNICAL REVIEW CHECKLIST RELATED TO INTERIM ESEP SUPPORTING IMPLEMENTATION OF NTTF R2.1, SEISMIC (TAC NO. MF5269)

Sent Date: 9/2/2015 5:46:48 PM Received Date: 9/2/2015 5:46:50 PM 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 "Wang, Weijun" <Weijun.Wang@nrc.gov>

Tracking Status: None "Gallucci, Ray" <Ray.Gallucci@nrc.gov>

Tracking Status: None "Patel, Pravin" <Pravin.Patel@nrc.gov>

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

Tracking Status: None "Graizer, Vladimir" <Vladimir.Graizer@nrc.gov>

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

Tracking Status: None Post Office: HQPWMSMRS07.nrc.gov Files Size Date & Time MESSAGE 3035 9/2/2015 5:46:50 PM VC Summer R2.1 Seismic ESEP NRC review.docx 48910 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 PROCESSINTERIM EVALUATION IMPLEMENTING NTTF RECOMMENDATION 2.1 SEISMIC VIRGIL C. SUMMER NUCLEAR STATION, UNIT 1 DOCKET NO.50-395 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 VC Summer Nuclear Station, Unit 1 By letter dated December 17, 20143,South Carolina Electric & Gas (SCE&G), 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 Virgil C. Summer Nuclear Station (VC Summer), Unit 1.

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 report4submittal

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

VC Summer Unit 1 used a scaled SSE at a ratio of 2.0.

Notes from the Reviewer:

1. The licensee used the maximum scaled ratio of 2.0 of the SSE because the GMRS exceeds the SSE by more than 2 times. The licensee used the scaled ratio for all items except the Condensate Storage Tank (CST).

2. Soil SSE (0.25 g) was developed for the surface. The licensee used GMRS, developed for the hard rock,located 85 ft below the plant grade as the RLGM for the CST founded at the grade by following guidance of EPRI 3002000704 Section 4, Option 2.This is acceptable for this purposes of this interim evaluation.

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

No deviation or deficiencies were found in the review of this particular section.

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

• 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 path Yes

• included FLEX Phase 2 and/or 3 connections

• considered installed FLEX Phase 2 and/or 3 equipment Yes Yes 3 ADAMS Accession NoML14357A168 4ADAMS Accession No. ML14092A250

NTTF Recommendation 2.1 Expedited Seismic Evaluation Process Technical Review Checklist for VC Summer Nuclear Station, Unit 1 Notes from the Reviewer: None Deviation(s) or Deficiency(ies), and Resolution:

No deviation or deficiencies were found in the review of this particular section.

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 Expedited Seismic Equipment List (ESEL)

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:

1. The licensee verified that major components in direct flow path using system notebooks.

2. The licensee credited manual valves requiring operation via "reach rods" in ESEL equipment list. The licensee stated that isometric drawings were used to determine if any manual valves required to operate in support of the FLEX functions can be operated using reach rods. Operator actions were outside of the scope of the interim evaluation, as such this is acceptable for the purposes of this interim evaluation.

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

No deviation or deficiencies were found in the review of this particular section.

For PWR Plants ONLY The licensee included indicators / instrumentation for the following functions:

level, pressure, temperature, that would be indicative of (but not explicitly Yes 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 licenseeconsidered indicators for the following functions:

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

NTTF Recommendation 2.1 Expedited Seismic Evaluation Process Technical Review Checklist for VC Summer Nuclear Station, Unit 1 Notes from the Reviewer:

1. The staff requested completion of the ESEL because of no details of pressure indicators/instruments for the RCS. The licensees responses (ML15159A805 and ML15229A089) updated the ESEP report and revised Table 7.1 to include all missing or inaccessible items and therefore completed the ESEL. The revision of the ESEP report adequately addressed the staffs concern and met the intent of the guidance for this interim evaluation.

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

No deviation or deficiencies were found in the review of this particular section.

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).

IV. Walkdown Approach The licensee:

• described the walkdown screening approach, including walk-bys and Yes walkdowns performed exclusively for the ESEP, in accordance with the guidance

• credited previous walkdown results, including a description of current N/A 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:

1. New walkdowns were performed for the interim evaluation. Previous walkdown results were used for background purposes only.

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

No deviation or deficiencies were found in the review of this particular section.

The licensee:

• described, as needed,adverse material condition of the equipment Yes (e.g., material degradation)

• credited previous walkdown results, included a description of current N/A action(s) to verify the present equipment condition (e.g., walk-bys),

meeting the intent of the guidance

NTTF Recommendation 2.1 Expedited Seismic Evaluation Process Technical Review Checklist for VC Summer Nuclear Station, Unit 1 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:

1. Screened-in items (anchors) are not found in Section6.5 of licensees ESEP report as referenced, however anchor failure modes for the equipment was listed in Table 6-4.

This is a typographical error and does not affect the conclusion of the evaluations.

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

No deviation or deficiencies were found in the review of this particular section.

The licensee reported deviations for VC Summer Unit 1. No Ifdeviations 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, including Yes any credited previous efforts (e.g., IndividualPlant Examination of External Events(IPEEE) consistent with the guidance

• the licensee addressed identified deviations consistent with the guidance, if any Yes 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 (see note 1) based on scaling

• described the development of ISRS based on new analysis Yes 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 Yes

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

• presented the results of HCLPF capacities including associated Yes

NTTF Recommendation 2.1 Expedited Seismic Evaluation Process Technical Review Checklist for VC Summer Nuclear Station, Unit 1 failure modes for screened-in ESEL items

• reviewed the ESEL items with the lowest HCLPF values to ensure Yes that their capacities are equal or greater than the RLGM Notes from the Reviewer:

1. All ISRS, with exception of the Condensate Storage Tank (CST), are developed based on proper scaling. The CST is supported on a surface mounted slab at grade. SSI is performed with the RLGM applied at rock elevation (85 ft below grade) to develop seismic demand for the CST. The GMRS is less than SSE in frequency range up to 5 Hz. This approach utilizes both allowed approaches in the guidance and therefore, is acceptable for the purpose of this interim evaluation.

2. Four items were identified as having HCLPF below the RLGM. As requested by the staff, the licensee described planned modifications to enhance seismic capacity of the plant, including actions to mitigate the four items, are summarized in Section 8.2 of the revised ESEP report in its responses (ML15159A805 and ML15229A089). The licensee also provided commitmentsto complete modifications. The revision of the ESEP report adequately addressed the staffs concerns andmet the intent of the guidance for this interim evaluation.

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

No deviation or deficiencies were found in the review of this particular section.

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, as Yes 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 Yes inaccessible items

• provided Regulatory Commitment to complete walkdowns. Yes VC Summer Unit 1 will complete walkdown during: the Fall 2015 refueling outage.

Notes from the Reviewer:

1. The orginal report (Rev 0, dated 12/15/2014) did not identify any inaccessible items. The licensee provided an updated ESEP report (also labeled Rev 0, dated 6/4/2015, ML15159A805), which included a list of inaccessible items and committed to complete the walkdowns. In its August 13, 2015, response (ML15229A089), the licensee committed to provide the results of the walkdown and HCLPF results by February 1, 2016.

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

No deviation or deficiencies were found in the review of this particular section.

NTTF Recommendation 2.1 Expedited Seismic Evaluation Process Technical Review Checklist for VC Summer Nuclear Station, Unit 1 The NRC staff concludes that the licensee:

• listed inaccessible items Yes

• committed to provide the results (e.g. walkdowns, walk-bys, etc.) of Yes the remaining inaccessible items consistent with the guidance

• substitutions, if needed, were appropriately justified Yes 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 consistent with the intent of the guidance

• provided Regulatory Commitment to complete modifications Yes

• provided Regulatory Commitment to report completion of Yes modifications.

VC Summer will:

• complete modifications no later than or during the planned Spring 2017 refueling outage.

• report completion of modifications 60 days after completion of the Spring 2017 refueling outage.

Notes from the Reviewer:

1. In the ESEP report the licensee indicated which modifcations would be performed by December 2015, December 2016 and during the Spring 2017 outage, which is in accordance with the schedule identified in the NEI letter. The staff requested clarification of licensees regulatory commitments. The licensees response (ML15229A089) revised its ESEP report and added new regulatory commitments in Section 8.4. Sixty days following completion of the second refueling outage after December 31, 2014 (scheduled for Spring 2017), the licensee will submit a letter to NRC confirming all ESEP modifications are complete.

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

No deviation or deficiencies were found in the review of this particular section.

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

NTTF Recommendation 2.1 Expedited Seismic Evaluation Process Technical Review Checklist for VC Summer Nuclear Station, Unit 1 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 the Virgil C. Summer Nuclear Station, Unit 1, in accordance with the guidance, the RLGM used its(scaledrock) SSE at the maximum ratio of 2.0. The application of this staff review is limited to the ESEP interim evaluation as part of the NTTF R2.1: Seismic activities. The staff did not identify deviations or exceptions from the guidance for the purposes this interim evaluation. As noted above, the licensee identified safety enhancing modifications based on the evaluation and committed to complete modifications by within two planned refueling outages of December 31, 2014, which is by Spring 2017. The licensee will report the completion of modifications within 60 days following completion of the second refueling outage after December 31, 2014 (Spring 2017).

In summary, by implementing the ESEP interim evaluation, the licensee demonstrated that additional assurance exists which supports continued plant safety and confirms that sufficient time exists to allow the completion of longer-term seismic evaluations to support regulatory decision making. The NRC staff concludes that the licensee responded appropriately to , Item (6) of the 50.54(f) letter, dated March 12, 2012, for Virgil C. Summer Nuclear Station, Unit 1.

Principal Contributors: Ray Gallucci, Kevin Roche, On Yee, Pravin Patel, Robert Pettis, Vladimir Graizer, Weijun Wang, Thomas Houston, (NRC Consultant)