BSEP 14-0131, Expedited Seismic Evaluation Process Report in Response to 10 CFR 50.54(f) Request for Information Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-lchi Accident

From kanterella
Jump to navigation Jump to search

Expedited Seismic Evaluation Process Report in Response to 10 CFR 50.54(f) Request for Information Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-lchi Accident
ML15005A074
Person / Time
Site: Brunswick  Duke Energy icon.png
Issue date: 12/18/2014
From: William Gideon
Duke Energy Corp
To:
Document Control Desk, Division of Operating Reactor Licensing
References
BSEP 14-0131
Download: ML15005A074 (51)
v • d • e


Text

William R. Gideon Vice President ENERGY, Brunswick Nuclear Plant P.O. Box 10429 Southport, NC 28461 o: 910.457.3698 December 18, 2014 10 CFR 50.54(f)

Serial: BSEP 14-0131 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

Subject:

Brunswick Steam Electric Plant, Unit Nos. 1 and 2 Renewed Facility Operating License Nos. DPR-71 and DPR-62 Docket Nos. 50-325 and 50-324 Expedited Seismic Evaluation Process Report in Response to 10 CFR 50.54(f)

Request for Information Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-lchi Accident

References:

1. Nuclear Energy Institute Letter, "Proposed Path Forward for NTTF Recommendation 2.1: Seismic Reevaluations," dated April 9, 2013, ADAMS Accession Number ML13101A379.
2. Electric Power Research Institute (EPRI) Final Report 1025287, "Seismic Evaluation Guidance; Screening, Prioritization and Implementation Details (SPID) for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic,"

dated February 2013.

3. Electric Power Research Institute Technical Report 3002000704, "Seismic Evaluation Guidance; Augmented Approach for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic," dated May 2013.
4. NRC Letter, "Electric Power Research Institute Final Draft Report XXXXXX, "Seismic Evaluation Guidance: Augmented Approach for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic," as an Acceptable Alternative to the March 12, 2012, Information Request for Seismic Reevaluations," dated May 7, 2013, ADAMS Accession Number ML13106A331.
5. Brunswick Steam Electric Plant letter, "Seismic Hazard and Screening Report (CEUS Sites), Response to NRC Request for Information Pursuant to 10 CFR 50.54(f)

Regarding the Seismic Aspects of Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident," dated March 31, 2014, ADAMS Accessions Number ML14106A461

6. NRC Letter, "Brunswick Steam Electric Plant, Units 1 and 2 - Screening and Prioritization Results of Information Provided Pursuant to Title 10 of the Code of Federal Regulations Part 50, Section 50.54(f), Seismic Hazard Reevaluations for Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-lchi Accident (TAC Nos. MF3824 and MF3825)," dated September 17, 2014, ADAMS Accession Number ML14231A964.

On April 9, 2013, the Nuclear Energy Institute notified the NRC in Reference 1 that, in addition to using the methods described in Electric Power Research Institute (EPRI) Report

U.S. Nuclear Regulatory Commission Page 2 of 3 1025287 (i.e., Reference 2), the industry planned "to augment that effort with a deterministic Expedited Seismic Evaluation to provide a timely demonstration of additional seismic margin and support near-term plant modifications to enhance safety." The augmented method described in Reference 3 was proposed by EPRI in May 2013, and was endorsed by the NRC on May 7, 2013, in Reference 4.

The augmented method proposed by EPRI included preparation and submittal of an Expedited Seismic Evaluation Process (ESEP) report to "provide additional seismic margin and expedite plant safety enhancements for certain core and containment cooling components while more detailed and comprehensive plant seismic risk evaluations are being performed." On March 31, 2014, Brunswick Steam Electric Plant (BSEP) stated in Reference 5 that the ESEP evaluation had been initiated and that BSEP Units 1 and 2 screened out for the seismic risk evaluation. The forthcoming ESEP report was acknowledged by the NRC on September 17, 2014, in Reference 6. The enclosed ESEP Report provides the required evaluation and is submitted in accordance with the schedule required by Reference 4.

This letter contains no new regulatory commitments.

If you have any questions regarding this report, please contact Mr. Lee Grzeck, Manager -

Regulatory Affairs, at (910) 457-2487.

I declare under penalty of perjury that the foregoing is true and correct. Executed on December 18, 2014.

S crelyQ William R. Gideon SWR/swr

Enclosure:

Expedited Seismic Evaluation Process (ESEP) Report, Brunswick Steam Electric Plant Unit 1 and Unit 2, dated December 10, 2014

U.S. Nuclear Regulatory Commission Page 3 of 3 cc (with enclosure):

U. S. Nuclear Regulatory Commission ATTN: Mr. Bill Dean, Director, Office of Nuclear Reactor Regulation 11555 Rockville Pike Rockville, MD 20852-2738 U. S. Nuclear Regulatory Commission, Region II ATTN: Mr. Victor M. McCree, Regional Administrator 245 Peachtree Center Ave, NE, Suite 1200 Atlanta, GA 30303-1257 U. S. Nuclear Regulatory Commission ATTN: Ms. April Scarbeary, NRC Senior Resident Inspector 8470 River Road Southport, NC 28461-8869 U. S. Nuclear Regulatory Commission ATTN: Mr. Andrew Hon (Mail Stop OWFN 8G9A) (Electronic Copy Only) 11555 Rockville Pike Rockville, MD 20852-2738 U.S. Nuclear Regulatory Commission ATTN: Mr. Peter Bamford (Mail Stop 08B3)

Washington, DC 20555-0001 Chair - North Carolina Utilities Commission P.O. Box 29510 Raleigh, NC 27626-0

BSEP 14-0131 Enclosure Brunswick Steam Electric Plant, Unit Nos. 1 and 2 Renewed Facility Operating License Nos. DPR-71 and DPR-62 Docket Nos. 50-325 and 50-324 Expedited Seismic Evaluation Process (ESEP) Report Total Pages in

Enclosure:

47

ESEP Report BSEP Unit 1 and Unit 2 EXPEDITED SEISMIC EVALUATION PROCESS (ESEP) REPORT BRUNSWICK STEAM ELECTRIC PLANT UNIT 1 AND UNIT 2 December 10, 2014 Page 1 of 26

ESEP Report BSEP Unit 1 and Unit 2 EXPEDITED SEISMIC EVALUATION PROCESS REPORT Table of Contents Executive Sum m ary ...................................................................................................... 3 1.0 Purpose and O bjective .............................................................................................. 4 2.0 Brief Summary of the FLEX Seismic Implementation Strategies ............................... 4 3.0 Equipm ent Selection Process and ESEL .................................................................... 5 4.0 Ground Motion Response Spectrum (GMRS) ......................................................... 11 5.0 Review Level Ground M otion (RLGM ) .................................................................... 13 6.0 Seism ic M argin Evaluation Approach ...................................................................... 16 7.0 Inaccessible Item s .................................................................................................. 21 8.0 ESEP Conclusions and Results ................................................................................. 23 9 .0 Re fe re n ce s .................................................................................................................. 25 Attachment A BSEP Unit 1 and Unit 2 Combined ESEL ................................................. Al Attachment B ESEP HCLPF Values and Failure Modes Tabulation, BSEP Units 1 and 2 ... B2 Attachment C Summary of FLEX Seismic Implementation Strategies Figures ............. C1 Page 2 of 26

ESEP Report BSEP Unit 1 and Unit 2 Executive Summary This report describes the Expedited Seismic Evaluation Process (ESEP) undertaken for the Brunswick Steam Electric Plant (BSEP) Units 1 and 2. The intent of the ESEP is to perform an interim action in response to the NRC's 50.54(f) letter [1] to demonstrate seismic margin through a review of a subset of the plant equipment that can be relied upon to protect the reactor core following beyond design basis seismic events. BSEP screens in for the ESEP because the Ground Motion Response Spectrum (GM RS) exceeds the Safe Shutdown Earthquake (SSE) for frequencies greater than 7 Hz.

The GMRS exceeds the BSEP SSE by more than two times, therefore the Review Level Ground Motion (RLGM) is taken at the ESEP specified maximum ratio of two times the SSE. The RLGM for the BSEP site is 0.32 PGA. The In-Structure Response Spectra (ISRS) for the ESEP were developed by linearly scaling the existing BSEP ISRS by the ESEP specified maximum ratio of two times the SSE.

BSEP performed a seismic margin assessment using the RLGM demand in accordance with the methodology of EPRI NP-6041-SL [7] for the ESEP. The major steps included equipment selection, screening, walkdowns, and Conservative Deterministic Failure Margin (CDFM) High Confidence Low Probability of Failure (HCLPF) calculations, when required. The screening process used the screening tables from Chapter 2 of EPRI NP-6041-SL [7]. The walkdowns were conducted by Seismic Qualification Utility Group (SQUG) qualified engineers and were documented on Screening Evaluation Work Sheets (SEWS) based on those contained in Appendix F of EPRI NP-6041-SL. Previous seismic walkdowns (Fukushima NTTF 2.3: Seismic, IPEEE, and USI A-46) were used to support the ESEP seismic evaluations.

No significant outliers or anchorage concerns were identified during the BSEP seismic walkdowns. Several block walls were identified in the proximity of Expedited Seismic Equipment List (ESEL) equipment. These block walls were assessed based on existing documentation to withstand the seismic loads resulting from the RLGM and either screened out or if necessary, a new HCLPF calculation was performed. Several ESEL items required HCLPF capacity calculations for anchorage. All of the ESEL items that required a HCLPF capacity calculation for anchorage were shown to have a HCLPF capacity greater than the RLGM. Some ESEL items were inaccessible but were determined to be seismically adequate for the RLGM based on past walkdown data, drawings and other documentation, and comparison to similar equipment that was accessible.

Based on the collective experience of the Seismic Review Team (SRT) in addition to existing and newly produced HCLPF calculations, all ESEL equipment capacities are determined to meet or exceed the RLGM demands. Therefore, no modifications are required for any of the items listed on the BSEP ESEL. No further walkdowns are planned for inaccessible items. In addition, per a letter from the NRC [27], BSEP screens out of performing a Seismic Risk Evaluation.

Page 3 of 26

ESEP Report BSEP Unit 1 and Unit 2 1.0 Purpose and Objective Following the accident at the Fukushima Dai-ichi nuclear power plant resulting from the March 11, 2011, Great Tohoku Earthquake and subsequent tsunami, the Nuclear Regulatory Commission (NRC) established a Near Term Task Force (NTTF) to conduct a systematic review of NRC processes and regulations and to determine if the agency should make additional improvements to its regulatory system. The NTTF developed a set of recommendations intended to clarify and strengthen the regulatory framework for protection against natural phenomena. Subsequently, the NRC issued a 50.54(f) letter on March 12, 2012 [1], requesting information to assure that these recommendations are addressed by all U.S. nuclear power plants. The 50.54(f) letter requests that licensees and holders of construction permits under 10 CFR Part 50 reevaluate the seismic hazards at their sites against present-day NRC requirements and guidance. Depending on the comparison between the reevaluated seismic hazard and the current design basis, further risk assessment may be required. Assessment approaches acceptable to the staff include a seismic probabilistic risk assessment (SPRA), or a seismic margin assessment (SMA). Based upon the assessment results, the NRC staff will determine whether additional regulatory actions are necessary.

This report describes the Expedited Seismic Evaluation Process (ESEP) undertaken for the Brunswick Steam Electric Plant (BSEP). The intent of the ESEP is to perform an interim action in response to the NRC's 50.54(f) letter [1] to demonstrate seismic margin through a review of a subset of the plant equipment that can be relied upon to protect the reactor core following beyond design basis seismic events.

The ESEP is implemented using the methodologies in the NRC endorsed guidance in EPRI 3002000704, Seismic EvaluationGuidance: Augmented Approach for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic (2].

The objective of this report is to provide summary information describing the ESEP evaluations and results. The level of detail provided in the report is intended to enable NRC to understand the inputs used, the evaluations performed, and the decisions made as a result of the interim evaluations.

2.0 Brief Summary of the FLEX Seismic Implementation Strategies The Brunswick Steam Electric Plant FLEX strategies for Reactor Core Cooling and Heat Removal, Reactor Inventory Control, and Containment Function are summarized below.

This summary is derived from the Brunswick Nuclear Plant Overall Integrated Plan (OIP) in response to the March 12, 2012, Commission Order EA-12-049 [3].

Reactor core cooling and heat removal is achieved using the safety relief valves (SRVs) to reject decay heat to the suppression pool (refer to Figure 6 in Attachment C). Rejected reactor coolant will be replaced with water injected using the Reactor Core Isolation Page 4 of 26

ESEP Report BSEP Unit 1 and Unit 2 Cooling (RCIC) system. The RCIC system will inject water from the suppression pool during Phase 1 response and from the Condensate Storage Tank (CST) during the Phase 2 response (refer to Figure 1 in Attachment C).

Reactor coolant inventory will be maintained using the RCIC system until decay heat has reduced reactor pressure below 50 psig. At or below this pressure, a portable FLEX pump will be used to continue water injection from the CST into the reactor vessel using a flow path via the Reactor Water Cleanup (RWCU) system into the "B" feed water injection line (refer to Figure 1 and Figure 3 in Attachment C). In the unlikely event this flow path is unavailable, an alternate flow path has been identified using the portable FLEX pump and the Residual Heat Removal (RHR) system (refer to Figure5 in Attachment C) using an existing integrated leak rate test line. Both flow paths require manual valve manipulation and temporary hoses to establish.

Primary Containment will be maintained by rejecting decay heat to the atmosphere using the Hardened Wetwell Vent (HWWV). Rejected heat will be transferred to the suppression pool via the SRVs. When the suppression pool begins to produce steam, the HWWV will be opened to relieve this steam to atmosphere (refer to Figure 6 in Attachment C). SRV and HWWV functionality will initially be maintained using the Backup Nitrogen System via installed nitrogen bottles. Additional capacity is being added through the addition of two nitrogen bottles (for a total of 12 per division). In the event sustained use of these systems results in depleting the nitrogen bottle supply, a portable FLEX air compressor will be installed to provide indefinite coping capability. To provide redundancy, primary and alternate connection points have been established for the air compressor connection (refer to Figure 4 in Attachment C).

In an Extended Loss of AC Power (ELAP), it is possible that the spent fuel pool (SFP) level may lower due to the loss of heat removal capability and the onset of boiling. Inventory loss will be compensated for by providing makeup capability using the portable FLEX pump with suction from the CST, discharging water through temporary hoses and an installed FLEX connection on the Residual Heat Removal System (refer to Figure 2 in Attachment C). To provide redundancy to this flow path, an alternate strategy has been created using temporary hose from the portable FLEX pump directly to the SFP. A method to provide SFP spray capability has also been created utilizing a portable FLEX pump, temporary hoses, and firefighting nozzles.

3.0 Equipment Selection Process and ESEL The selection of equipment for the Expedited Seismic Equipment List (ESEL) followed the guidelines of EPRI 3002000704 [2]. The ESELs for Unit 1 and Unit 2 are documented in Attachment A of this document. Formal ESEL development is documented in BSEP EVAL EC 91485 [19].

3.1 Equipment Selection Process and ESEL The selection of equipment to be included on the ESEL was based on installed plant equipment credited in the FLEX strategies during Phase 1, 2 and 3 Page 5 of 26

ESEP Report BSEP Unit 1 and Unit 2 mitigation of a Beyond Design Basis External Event (BDBEE), as outlined in the BSEP Overall Integrated Plan (OIP) in Response to the March 12, 2012, Commission Order EA-12-049 [3]. The OIP provides the BSEP FLEX mitigation strategy and serves as the basis for equipment selected for the ESEP.

The scope of "installed plant equipment" includes equipment relied upon for the FLEX strategies to sustain the critical functions of core cooling and containment integrity consistent with the BSEP OIP [3]. FLEX recovery actions are excluded from the ESEP scope per EPRI 3002000704 [2]. The overall list of planned FLEX modifications and the scope for consideration herein is limited to those required to support core cooling, reactor coolant inventory and subcriticality, and containment integrity functions. Portable and pre-staged FLEX equipment (not permanently installed) are excluded from the ESEL per EPRI 3002000704 [2].

The ESEL component selection followed the EPRI guidance outlined in Section 3.2 of EPRI 3002000704.

1. The scope of components is limited to that required to accomplish the core cooling and containment safety functions identified in Table 3-1 of EPRI 3002000704. The instrumentation monitoring requirements for core cooling/containment safety functions are limited to those outlined in the EPRI 3002000704 guidance, and are a subset of those outlined in the BSEP OIP [3].
2. The scope of components is limited to installed plant equipment, and FLEX connections necessary to implement the BSEP OIP [3] as described in Section 2.0.
3. The scope of components assumes the credited FLEX connection modifications are implemented, and are limited to those required to support a single FLEX success path (i.e., either "Primary" or "Back-up/Alternate").
4. The ESEL was developed based on the "Primary" FLEX success path identified in the BSEP OIP [3] and subsequent success path evolutions as detailed in EC 91485 [19]. No portions of the "Back-up/Alternate" FLEX success path were evaluated in lieu of the "Primary" success path in development of the ESEL.
5. Phase 3 coping strategies are included in the ESEP scope, whereas recovery strategies are excluded.
6. Structures, systems, and components excluded per the EPRI 3002000704 [2]

guidance are:

  • Structures (e.g. containment, reactor building, control building, auxiliary building, etc.)
  • Piping, cabling, conduit, HVAC, and their supports.
  • Manual valves and rupture disks.

Page 6 of 26

ESEP Report BSEP Unit 1 and Unit 2

Other notable plant equipment that screened out of the BSEP ESEL included DC Battery Room fans, RCIC turbine supply steam line drain pot drain line shutoff valves, and RCIC Steam Detection Isolation Signal Equipment as justified in BSEP EVAL EC 91485 [19].

3.1.1 ESEL Development The ESEL was developed by reviewing the BSEP OIP [3] to determine the major equipment involved in the FLEX strategies. Further reviews of plant drawings (e.g., Process and Instrumentation Diagrams (P&IDs) and Electrical One Line Diagrams) were performed to identify the boundaries of the flowpaths to be used in the FLEX strategies and to identify specific components in the flowpaths needed to support implementation of the FLEX strategies. Boundaries were established at an electrical or mechanical isolation device (e.g., isolation amplifier, valve, etc.) in branch circuits / branch lines off the defined strategy electrical or fluid flowpath. P&IDs were the primary reference documents used to identify mechanical components and instrumentation. The flow paths used for FLEX strategies were selected and specific components were identified using detailed equipment and instrument drawings, piping isometrics, electrical schematics and one-line drawings, system descriptions, design basis documents, etc., as necessary.

3.1.2 Mechanical Equipment Mechanical equipment that was identified as necessary to ensure the primary FLEX success path was added to the ESEL. P&IDs were reviewed to follow the flow paths associated with the primary FLEX success path to ensure all involved equipment was included on the ESEL.

The equipment chosen included valves, pumps, safety relief valves, drain pots, steam condensers, and others. The list did not include equipment such as manual valves, rupture disks, and pressure relief valves not operated as part of the FLEX strategy. Valves of the categories in Table 3.1 were examined, with some included in the ESEL as required by EPRI 3002000704 [2]:

Page 7 of 26

ESEP Report BSEP Unit 1 and Unit 2 Table 3-1. Valve Categories Normal: Open - FLEX: Open These valves do not need to change position after or Normal: Closed - FLEX: Closed during a BDB seismic event, but must maintain the pressure boundary (such as drain valves, or MOVs in the flow path that do not need to be repositioned). These valves need not be included in the ESEL.

Normal: Open - FLEX: Closed These valves DO need to change position after or during a Normal: Closed - FLEX: Open BDB seismic event, and must maintain the FLEX Response Path. Motor Operated Valves of this sort must be included in the ESEL, while manual valves need not be included.

Normal: N/A - FLEX: N/A These valves need to function during or after a BDB seismic event, but are passive mechanical devices (such as check valves). These valves need not be included in the ESEL.

Normal: Closed - This equipment may be operated during or after a BDB FLEX: Variable Position seismic event, but do not need to be repositioned (such as SRVs). These valves must be included in the ESEL.

Equipment IDs for equipment associated with actuation of MOVs or air operated valves were not individually listed in the ESEL. The valve actuators were considered sub-components to be evaluated as part of the listed valve review.

3.1.3 Power Operated Valves Page 3-3 of EPRI 3002000704 [2] notes that power operated valves not required to change state are excluded from the ESEL. Page 3-2 also notes that, "functional failure modes of electrical and mechanical portions of the installed Phase 1 equipment should be considered (e.g. RCIC/ Auxiliary Feedwater (AFW) trips)." To address this concern, the following guidance is applied in the BSEP ESEL for functional failure modes associated with power operated valves:

  • Power operated valves not required to change state as part of the FLEX mitigation strategies were not included on the ESEL. The seismic event also causes the ELAP event; therefore, the valves are incapable of spurious operation as they would be de-energized.
  • Power operated valves not required to change state as part of the FLEX mitigation strategies during Phase 1, and are re-energized and operated during subsequent Phase 2 and 3 strategies, were not evaluated for spurious valve operation as the seismic event that caused the ELAP has passed before the valves are re-powered.

3.1.4 Piping Connections Item 2 in Section 3.1 above notes that the scope of equipment in the ESEL includes "... FLEX connections necessary to implement the BSEP OIP [3] as described in Section 2." Item 3 in Section 3.1 also notes that, "The scope of components assumes the credited FLEX connection modifications are Page 8 of 26

ESEP Report BSEP Unit 1 and Unit 2 implemented, and are limited to those required to support a single FLEX success path (i.e., either "Primary" or "Back-up/Alternate")."

Item 6 in Section 3.1 above further explains that "Piping, cabling, conduit, HVAC, and their supports" are excluded from the ESEL scope in accordance with EPRI 3002000704 [2].

Therefore, piping and pipe support connections are excluded from the scope of the ESEP evaluation. However, any active valves in the connection flow paths are included in the ESEL.

3.1.5 Electrical Equipment Electrical equipment was selected based on both the mechanical and electrical components necessary to implement the primary FLEX success paths. Drawings were reviewed to ensure all intermediate components were included. This intermediate equipment included components associated with RCIC logic and ADS logic for relays that could lock-out/seal-in. All relays that were examined were determined to not lock-out or seal-in, and as such, were not included as components in the ESEL. All mechanical equipment, as discussed above in Section 3.1.2, was reviewed to ensure motive power for any equipment was included in the electrical equipment portions of the ESEL.

The equipment chosen consisted of electrical cabinets, switchgears, batteries, and battery chargers. The scope of the equipment does not include support items such as cables, cable trays, or conduit as discussed in Section 3.1 Item 6 above.

3.1.6 Critical Instruments Actions specified in plant procedures/guidance for loss of AC power are predicated on the use of instrumentation and controls powered by station batteries. A set of key reactor/containment indications necessary to support FLEX primary success path implementation was defined for the BSEP OIP [3] and provided in Table 3-2:

Table 3-2. Key Reactor/Containment Parameters RPV Level RPV Pressure Drywell Pressure Suppression Pool Temperature Suppression Pool Level A number of redundant "critical instruments" (available with a loss of all AC power and UPS de-energized) were listed in the BSEP OIP [3]. For purposes of the ESEL, this list of "critical" instruments" was reduced to one indication instrument loop per key parameter as permitted per EPRI 3002000704 [2]. In Page 9 of 26

ESEP Report BSEP Unit 1 and Unit 2 addition to including indicators on the final ESEL, supporting indication instrument loop components were added as well. These included pressure/level/temperature transmitters, transmitter racks, indicator panels, and instrument loop power components such as inverters/power supplies/master trip units.

3.1.7 RCIC Isolation Equipment Having any inadvertent RCIC isolation signals could prevent the RCIC system from starting up or accomplishing its objective of providing vessel inventory makeup. Since both divisions of RCIC isolation signals could impair RCIC system operation, the division signals from both divisions were accounted for in the ESEL. Isolation equipment included in the list includes Pressure Switches, Panels, Instrument Racks, Inverters, Power Supplies, Signal Converters, Electronic Trip Units, and Trip Calibration Cabinets. Isolation signals associated with the following (Table 3-3) were accounted for:

Table 3-3. Isolation Signals "T 'K ina ~

Turbine Exhaust Diaphragm High Pressure Manual Isolation Steam Line High Differential Pressure Or Steam Line High Differential Pressure or Instant Instant Line Break Line Break Steam Supply Pressure Low Steam Supply Pressure Low Isolation Signal Sealed In Turbine Exhaust Diaphragm High Pressure Isolation Signal Seal-In 3.1.8 Pull Boxes Pull boxes were deemed unnecessary to add to the ESELs as these components provide completely passive locations for pulling or installing cables. No breaks or connections in the cabling are included in pull boxes. Pull boxes were considered part of conduit and cabling, which are excluded in accordance with EPRI 3002000704 [2].

3.1.9 Termination Cabinets Termination cabinets, including cabinets necessary for FLEX Phase 2 and Phase 3 connections, provide consolidated locations for permanently connecting multiple cables. The termination cabinets and the internal connections provide a completely passive function; however, the cabinets are included in the ESEL to ensure industry knowledge on panel/anchorage failure vulnerabilities is addressed.

3.1.10 Critical Instrumentation Indicators Critical indicators and recorders are typically physically located on panels/cabinets and are included as separate components; however, seismic evaluation of the instrument indication may be included in the panel/cabinet seismic evaluation (rule-of-the-box).

Page 10 of 26

ESEP Report BSEP Unit 1 and Unit 2 3.2 Justification for Use of Equipment That Is Not The Primary Means for FLEX Implementation All equipment necessary to fulfill the primary FLEX success path for BSEP has been accounted for in the ESEL.

The complete combined ESEL for Unit 1 and Unit 2 are presented in Attachment A.

Formal ESEL development is documented in BSEP EVAL EC 91485 [19].

4.0 Ground Motion Response Spectrum (GMRS) 4.1 Plot of GMRS Submitted by BSEP The GMRS for the BSEP site, as reported in [4] for 5% damping, is provided as Figure 4-1 and Table 4-1. The site control point elevation was taken to be the bottom of the reactor building basemat at elevation -28.33 ft.

Mean Soil UHRS and GMRS at Brunswick 1.2 a-1E-5 UHRS 0.8 I-GMRS 0.6 0 -1E-4 UHRS U

C CL 0.4 0.2 0.

0.1 1 10 100 Spectral frequency, Hz Figure 4-1. UHRS for 1E-4 and 1E-5 and GMRS at control point for BSEP (5%-damped response spectra).

Table 4-1. Tabulated BSEP GMRS Frequency (Hz) Acceleration (g) 0.100 0.01920 0.125 0.02390 0.150 0.02870 0.200 0.03830 0.250 0.04790 0.300 0.05750 Page 11 of 26

ESEP Report BSEP Unit 1 and Unit 2 Table 4-1. Tabulated BSEP GMRS Frequency (Hz) Acceleration (g) 0.350 0.06700 0.400 0.07660 0.500 0.09580 0.600 0.10500 0.700 0.11400 0.800 0.12100 0.900 0.12400 1.000 0.12600 1.250 0.14400 1.500 0.15200 2.000 0.17500 2.500 0.17100 3.000 0.19900 3.500 0.21600 4.000 0.23500 5.000 0.27900 6.000 0.33400 7.000 0.39000 8.000 0.45300 9.000 0.50700 10.000 0.55500 12.500 0.56300 15.000 0.49400 20.000 0.36200 25.000 0.29900 30.000 0.26900 35.000 0.25300 40.000 0.23800 50.000 0.21600 60.000 0.20500 70.000 0.20000 80.000 0.19700 90.000 0.19500 100.000 0.19400 Page 12 of 26

ESEP Report BSEP Unit I and Unit 2 4.2 Comparison to Safe Shutdown Earthquake (SSE)

The site GMRS and the BSEP 5% damped horizontal SSE (as reported in [4]) are shown in Figure 4-2. In approximately the 7 to 10 Hz range of the response spectrum the GMRS exceeds the SSE by a factor of approximately 2.19 at 10 Hz.

The tabulated SSE values are provided in Table 5-1 0.6 . . .....

0 .5 . . . . . . .... . .

  • 0.4 . . . . ...... .. .

04 0.3 SI -.-- ... - l SSE

.I\- GMRS 0..

0.1 - -- 1 0.0 - - ..... I 0 1 10 100 Spectral Frequency, Hz Figure 4-2. BSEP GMRS and 5% Damped Horizontal SSE Comparison 5.0 Review Level Ground Motion (RLGM) 5.1 Description of RLGM Selected Since the greatest ratio of the GMRS to the SSE in the 1 to 10 Hz range is 2.19 at 10 Hz, the BSEP RLGM is taken at the ESEP specified maximum ratio of two times the SSE per Section 4 of EPRI 3002000704 [2]. The RGLM in terms of peak ground acceleration (PGA) at 5% spectral damping for the BSEP site is 0.32g. The tabulated RLGM is provided in Table 5-1. The RLGM and GMRS are shown graphically in Figure 5-1.

Page 13 of 26

ESEP Report BSEP Unit 1 and Unit 2 Table 5-1. Tabulated BSEP RLGM & SSE RLGM SSE Frequency (Hz) Acceleration (g) Acceleration (g) 0.333 0.152 0.076 0.354 0.161 0.081 0.389 0.178 0.089 0.428 0.195 0.098 0.471 0.215 0.107 0.518 0.236 0.118 0.569 0.260 0.13 0.626 0.286 0.143 0.689 0.314 0.157 0.757 0.346 0.173 0.833 0.381 0.19 0.916 0.419 0.209 1.007 0.460 0.23 1.108 0.506 0.253 1.218 0.557 0.279 1.34 0.613 0.306 1.474 0.674 0.337 1.621 0.741 0.371 1.783 0.816 0.408 1.923 0.880 0.44 1.96 0.880 0.44 2.156 0.880 0.44 2.371 0.880 0.44 2.608 0.880 0.44 2.868 0.880 0.44 3.154 0.880 0.44 3.469 0.880 0.44 3.815 0.880 0.44 4.195 0.880 0.44 4.614 0.880 0.44 5.074 0.880 0.44 5.581 0.880 0.44 6.138 0.880 0.44 6.667 0.880 0.44 6.75 0.865 0.433 7.423 0.761 0.38 Page 14 of 26

ESEP Report BSEP Unit 1 and Unit 2 Table 5-1. Tabulated BSEP RLGM & SSE RLGM SSE Frequency (Hz) Acceleration (g) Acceleration (g) 8.164 0.669 0.335 8.979 0.588 0.294 9.875 0.517 0.259 10.86 0.455 0.227 11.943 0.400 0.2 13.135 0.352 0.176 14.085 0.320 0.16 14.446 0.320 0.16 15.887 0.320 0.16 17.472 0.320 0.16 19.215 0.320 0.16 21.133 0.320 0.16 23.241 0.320 0.16 25.56 0.320 0.16 28.111 0.320 0.16 30.915 0.320 0.16 34 0.320 0.16 1.000 -

0.900 -

0.800 0 0.700 1 L0.600 -

.0400 -

SA 0.200 Ol 0.000 0.100 1.000 10.000 100.000 Spectral Frequency, Hz Figure 5-1. BSEP RLGM and GMRS Page 15 of 26

ESEP Report BSEP Unit 1 and Unit 2 5.2 Method to Estimate In-Structure Response Spectra (ISRS)

The ISRS for the ESEP were developed by linearly scaling the existing BSEP ISRS by the ESEP specified maximum ratio of two times the SSE. For the Containment, the A-46 response spectra were used in place of the design basis SSE spectra.

For Control Building and Diesel Generator Buildings, the original design basis SSE spectra are used. There are no ESEL components in other Seismic Class I structures.

6.0 Seismic Margin Evaluation Approach It is necessary to demonstrate that ESEL items have sufficient seismic capacity to meet or exceed the demand characterized by the RLGM. The seismic capacity is characterized as the PGA for which there is a high confidence of a low probability of failure (HCLPF).

The PGA is associated with a specific spectral shape, in this case the 5%-damped RLGM spectral shape. The HCLPF capacity must be equal to or greater than the RLGM PGA.

The criteria for seismic capacity determination are given in Section 5 of EPRI 3002000704 [2].

There are two basic approaches for developing HCLPF capacities:

1. Deterministic approach using the conservative deterministic failure margin (CDFM) methodology of EPRI NP-6041-SL, A Methodology for Assessment of Nuclear Power Plant Seismic Margin (Revision 1) [7].
2. Probabilistic approach using the fragility analysis methodology of EPRI TR-103959, Methodology for Developing Seismic Fragilities [8].

Page 16 of 26

ESEP Report BSEP Unit 1 and Unit 2 6.1 Summary of Methodologies used BSEP performed a seismic margin assessment using the RLGM demand in accordance with the methodology of EPRI NP-6041-SL [71 for the ESEP. The major steps included screening, walkdowns, and CDFM HCLPF calculations, when required. The screening process used the screening tables from Chapter 2 of EPRI NP-6041-SL [7]. The walkdowns were conducted by engineers trained to the SQUG Walkdown Screening and Seismic Evaluation Training Course and were documented on Screening Evaluation Work Sheets (SEWS) based on those contained in Appendix F of EPRI NP-6041-SL. Anchorage capacity calculations used the CDFM criteria from EPRI NP-6041-SL. Seismic demand was the RLGM equal to two times the BSEP SSE (and corresponding ISRS) anchored to 0.32 PGA.

6.2 HCLPF Screening Process The SMA was performed using a RLGM equal to two times the SSE for the ESEP, which was anchored to 0.32g PGA. Any components whose SMA-based HCLPF capacity exceeds the RLGM can be screened out from HCLPF calculations. The screening tables in EPRI NP-6041-SL [7] are based on ground peak spectral accelerations of 0.8g and 1.2g. The RLGM for the BSEP site results in a ground peak spectral acceleration between these values. Therefore, the 0.8 - 1.2g column of Table 2.4 of EPRI NP-6041-SL [7] is relevant for applying seismic screening criteria for plant equipment listed on the ESEL. It should be noted however that the GMRS peak spectral acceleration is less than 0.6g, which would allow for screening based on the lowest level requirements from EPRI NP-6041-SI if the GMRS were used. The anchorage capacity calculations were based on SSE floor response spectra scaled to the RLGM of two times the BSEP SSE.

Equipment for which the screening caveats were met and for which the anchorage capacity exceeded the RLGM seismic demand of two times the BSEP SSE can be screened out from ESEP seismic capacity determination because the HCLPF capacity exceeds the RLGM.

The combined Unit 1 and Unit 2 BSEP ESEL contains 238 items. Of these, 52 are valves, both power-operated and safety relief valves. In accordance with Table 2-4 of EPRI NP-6041-SL [7], active valves may be assigned a functional capacity of 1.2g peak spectral acceleration without any review other than recommended evaluations for motor operated valves (MOVs) on piping with a diameter of 2 inches or less, and anchorage is not a failure mode. Therefore, valves on the ESEL may be screened out from ESEP seismic capacity determination, subject to the caveat regarding MOVs on piping 2 inches or less in diameter, for which the Seismic Review Team (SRT) reviewed individually.

The non-valve components in the ESEL are generally screened based on the SMA results. If the SMA showed that the component met the EPRI NP-6041-SL screening caveats and the CDFM capacity exceeded the RLGM demand, the component can be screened out from the ESEP capacity determination. Per EPRI Page 17 of 26

ESEP Report BSEP Unit 1 and Unit 2 3002000704 [2] and EPRI NP-6041-SL [7], equipment more than 40 ft above effective grade were evaluated considering in-structure demands and guidance in EPRI 1019200 [26].

6.3 Seismic Walkdown Approach 6.3.1 Walkdown Approach Walkdowns were performed in accordance with the criteria provided in Section 5 of EPRI 3002000704 [2], which refers to EPRI NP-6041-SL [7] for the Seismic Margin Assessment process. Pages 2-26 through 2-30 of EPRI NP-6041-SL [7]

describe the seismic walkdown criteria, including the following key criteria.

"The SRT [Seismic Review Team] should "walk by" 100% of all components which are reasonablyaccessible and in non-radioactiveor low radioactive environments. Seismic capabilityassessment of components which are inaccessible, in high-radioactiveenvironments, or possibly within contaminated containment,will have to rely more on alternatemeans such as photographicinspection, more reliance on seismic reanalysis,and possibly, smaller inspection teams and more hurriedinspections. A 100% "walk by" does not mean complete inspection of each component, nor does it mean requiring an electricianor other technician to de-energize and open cabinets or panelsfor detailedinspection of all components. This walkdown is not intended to be a QA or QC review or a review of the adequacy of the component at the SSE level.

If the SRT has a reasonable basisfor assuming that the group of components are similarand are similarly anchored, then it is only necessary to inspect one component out of this group. The "similarity-basis"should be developed before the walkdown during the seismic capability preparatorywork (Step 3) by reference to drawings, calculationsor specifications. The one component of each type which is selected should be thoroughly inspected which probably does mean de-energizing and opening cabinets or panels for this very limited sample. Generally, a sparerepresentativecomponent can be found so as to enable the inspection to be performed while the plant is in operation. At least for the one component of each type which is selected, anchorage should be thoroughly inspected.

The walkdown procedureshould be performed in an ad hoc manner. For each class of components the SRT should look closely at the first items and compare the field configurations with the construction drawings and/or specifications. If a one-to-one correspondenceis found, then subsequent items do not have to be inspected in as great a detail. Ultimately the walkdown becomes a "walk by" of the component class as the SRT becomes confident that the constructionpattern is typical. This procedurefor inspection should be repeatedfor each component class; although, during the actual walkdown the SRT may be inspectingseveral classes of components in Page 18 of 26

ESEP Report BSEP Unit 1 and Unit 2 parallel. If serious exceptions to the drawings or questionable construction practicesare found then the system or component class must be inspected in closer detail until the systematic deficiency is defined.

The 100% "walk by" is to look for outliers, lack of similarity,anchoragewhich is different from that shown on drawings or prescribedin criteriafor that component, potentialSI [Seismic Interaction1 ] problems, situations that are at odds with the team members' past experience, and any other areas of serious seismic concern. If any such concerns surface, then the limited sample size of one component of each type for thorough inspection will have to be increased. The increasein sample size that should be inspected will depend upon the number of outliers and different anchorages,etc., which are observed. It is up to the SRT to ultimately select the sample size since they are the ones who are responsiblefor the seismic adequacy of all elements which they screen from the margin review. Appendix D gives guidancefor sampling selection."

For BSEP, the decision to perform a walk by versus detailed walkdown was based on a pre-screening of the available documentation for each of the components listed in the ESEL. ESEL items were pre-screened out of a detailed walkdown based on previous walkdown data and existing calculations showing a seismic capacity greater than the RGLM. Items that were pre-screened out of a detailed walkdown were scheduled for a walk by. For items not pre-screened for a walk by, a detailed walkdown was performed. Any additional items that were added to the ESEL during the ongoing ESEP evaluation phase were identified for a detailed walkdown.

6.3.2 Application of Previous Walkdown Information Previous seismic walkdowns (including results and findings) were used to support the ESEP seismic evaluations. Some of the components on the ESEL were included in the NTTF 2.3 seismic walkdowns [17 & 18]. Those walkdowns were well documented and recent enough that they did not need to be repeated for the ESEP. However for BSEP, if the ESEL item was readily accessible, a walk by or detailed walkdown was performed regardless of whether a walkdown was performed for the NTTF 2.3 seismic evaluations.

Several ESEL items were previously walked down during the BSEP Seismic IPEEE program [9] and for Unresolved Safety Issue (USI) A-46 [25]. Those walkdown results were reviewed and the following steps were taken to confirm that the previous walkdown conclusions remained valid.

  • A walk by (if accessible) was performed to confirm that the equipment material condition and configuration is consistent with the walkdown 1 EPRI 3002000704 (2] page 5-4 limits the ESEP seismic interaction reviews to "nearby block walls" and "piping attached to tanks" which are reviewed "to address the possibility of failures due to differential displacements."

Page 19 of 26

ESEP Report BSEP Unit 1 and Unit 2 conclusions and that no new significant interactions related to block walls or piping attached to tanks exist'.

If the ESEL item was screened out based on the previous walkdown, that screening evaluation was reviewed and reconfirmed for the ESEP.

6.3.3 Significant Walkdown Findings Consistent with the guidance from NP-6041-SL [7], no significant outliers or anchorage concerns were identified during the BSEP seismic walkdowns. The following findings were noted during the walkdowns.

" Several block walls were identified in the proximity of ESEL equipment.

These block walls were assessed for their structural adequacy based on existing documentation to withstand the seismic loads resulting from the RLGM. If necessary a new HCLPF calculation was performed. For any cases where the block wall represented the HCLPF failure mode for an ESEL item, it is noted in the tabulated HCILPF values described in Section 6.6. HCLPF capacities for block walls were determined in accordance with EPRI NP-6041-SL, Appendix R [7]. All block walls requiring a HCLPF calculation were shown to have a HCLPF capacity greater than the RLGM. No modifications for these walls are required.

" Several ESEL items required HCLPF capacity calculations for anchorage. All of the ESEL items that required a HCLPF capacity calculation for anchorage were shown to have a HCLPF capacity greater than the RLGM. No modifications for these items are required.

6.4 HCLPF Calculation Process ESEL items at BSEP were evaluated using the criteria in EPRI NP-6041-SL [7].

Those evaluations included the following steps:

" Performing detailed seismic capability walkdowns for equipment not included in previous seismic walkdowns (USI A-46, IPEEE, and NTTF 2.3) to evaluate the equipment installed plant conditions

  • Performing screening evaluations using the screening tables in EPRI NP-6041-SL as described in Section 6.2 and
  • Performing HCLPF calculations considering various failure modes that include both structural failure modes (e.g. anchorage, load path etc.) and functional failure modes. Typically functional failure modes were screened using Table 2-4 of EPRI NP-6041-SL [7].

All HCLPF calculations were performed using the CDFM methodology of EPRI NP-6041-SL [7] and are documented in Reference [10]. Each calculation evaluates the demand and capacity of the equipment's (or nearby masonry walls) critical failure modes and derives a HCLPF capacity from the results of the evaluation.

Page 20 of 26

ESEP Report BSEP Unit 1 and Unit 2 6.5 Functional Evaluations of Relays There are no relays on the BSEP ESEL, refer to Section 3.1.5 of this document.

6.6 Tabulated ESEL HCLPF Values (Including Key Failure Modes)

Tabulated ESEL HCLPF values are provided in Attachment B for BSEP Unit I and Unit 2. The following notes apply to the information in the tables.

  • For items screened out using EPRI NP-6041-SL [7] screening tables, the screening level can be provided as >RLGM and the failure mode can be listed as "Screened", (unless the controlling HCLPF value is governed by anchorage).

" For items where anchorage controls the HCLPF value, the HCLPF value is listed in the table and the failure mode is noted as "anchorage."

  • For items where nearby masonry walls control the HCLPF value, the HCLPF value of the wall is listed in the table and the failure mode is noted as "masonry wall".

7.0 Inaccessible Items 7.1 Identification of ESEL items inaccessible for walkdowns 7.1.1 SRVs and Accumulators All of the Safety Relief Valves (SRVs) and Accumulators in the BSEP Drywell were inaccessible during the ESEP walkdowns. These items were inaccessible due to the fact that the SRVs and Accumulators were located in a high radiation area, even during an outage. However, two of the SRVs for Unit 2 (2-B21-F031C and 2-B21-FO13G) and one of the SRVs for Unit 1 (1-B21-FO13J) were walked down during the NTTF 2.3 Seismic Walkdowns [17,18]. The SRT reviewed the data from the NTTF 2.3 Seismic Walkdowns and IPEEE/A-46 walkdowns in the 1990s.

The majority of the SRVs and Accumulators were screened from further review by the IPEEE SRT. The few issues that were noted by the IPEEE/A-46 SRT were resolved [25].

In addition, EPRI NP-6041-SL [7] Table 2.4 recommends evaluations for equipment mounted at elevations greater than 40 ft above the effective grade if the horizontal floor spectrum exceeds 2g. The PSA for the RLGM ISRS at elevation 55 ft and below for the BSEP Drywell are less than 2g. Furthermore, EPRI NP-6041-SL [7] Table 2-4 recommends evaluations for motor operated valves on piping lines less than 2 inches in diameter. The SRVs in the BSEP Drywell consist of a 6" inlet and a 10" outlet.

Lastly, the SRVs are subject to regular maintenance and testing as documented in BSEP procedures.

Page 21 of 26

ESEP Report BSEP Unit 1 and Unit 2 Based on the above discussion, the ESEP SRTjudged the SRVs and Accumulators to be adequate for the RLGM and no further walkdowns for these items have been planned.

7.1.2 Motor Control Centers (MCCs) and Distribution Panels A number of MCCs (1-1CB, 1-XDB, 2-2CB, and 2-XDB) and Distribution Panels (1-1B-25OVDC, 2-2B-25OVDC, 1-3B, and 2-4B) were externally inspected but were not opened due to being in an energized state. Each of these items were included in the IPEEE/A-46 walkdowns. The ESEP SRT reviewed the IPEEE/A-46 walkdown data, other documentation, and referenced calculations. The concerns and resolutions for problems identified by the IPEEE/A-46 SRT were reviewed. The ESEP SRT made determinations relative to the seismic capacity versus RLGM demand based on the past walkdown documentation and calculations. A HCLPF calculation was performed for MCCs 1-XDB and 2-XDB

[23]. Based on the existing documentation and the HCLPF calculations, the SRT judged the MCCs and Distribution Panels to have sufficient capacity for the RLGM. No further walkdowns for these items are planned.

7.1.3 Torus Temperature Elements One temperature element in the Reactor Building for each Unit (1-CAC-TE-778-6 and 2-CAC-TE-778-6) was unavailable at the time the walkdowns were completed. EPRI NP-6041-SL states that items that are inaccessible, in high radioactive environments or possibly within contaminated areas, will have to rely on alternate means such as photographic inspection, more reliance on seismic reanalysis, and possibly smaller inspection teams and more hurried inspections. The SRT judged the temperature elements to be seismically adequate with rugged supports based on review of the items installation drawings and specifications. No further walkdowns for these items are planned.

7.1.4 Switchgear Transformers The panels for 1-E6 and 2-E8 were not removed since the items were energized.

The transformers for these items were recently replaced. The SRT judged the switchgear equipment adequate for the RLGM based on an evaluation of previous walkdowns, inspections, engineering change packages, and calculations. The calculations reviewed were for similar cabinets at the DGB 50' elevation since 1-E6 and 2-E8 could not be opened. No further walkdowns are planned for these items.

7.2 Planned Walkdown / Evaluation Schedule / Close Out No further walkdowns for the inaccessible items in Section 7.1 of this report are planned based on the justifications provided.

Page 22 of 26

ESEP Report BSEP Unit 1 and Unit 2 8.0 ESEP Conclusions and Results 8.1 Supporting Information BSEP has performed the ESEP as an interim action in response to the NRC's 50.54(f) letter [1]. The ESEP was performed using the methodologies in the NRC endorsed guidance in EPRI 3002000704 [2].

The ESEP provides an important demonstration of seismic margin and expedites plant safety enhancements through evaluations of plant equipment that can be relied upon to protect the reactor core following beyond design basis seismic events.

The ESEP is part of the overall BSEP response to the NRC's 50.54(f) letter [1]. On March 12, 2014, NEI submitted to the NRC results of a study [12] of seismic core damage risk estimates based on updated seismic hazard information as it applies to operating nuclear reactors in the Central and Eastern United States (CEUS).

The study concluded that "site-specific seismic hazards show that there [...] has not been an overall increase in seismic risk for the fleet of U.S. plants" based on the re-evaluated seismic hazards. As such, the "current seismic design of operating reactors continues to provide a safety margin to withstand potential earthquakes exceeding the seismic design basis."

The NRC's May 9, 2014 NTTF 2.1 Screening and Prioritization letter [14]

concluded that the "fleetwide seismic risk estimates are consistent with the approach and results used in the GI-199 safety/risk assessment." The letter also stated that "As a result, the staff has confirmed that the conclusions reached in GI-199 safety/risk assessment remain valid and that the plants can continue to operate while additional evaluations are conducted."

An assessment of the change in seismic risk for BSEP was included in the fleet risk evaluation submitted in the March 12, 2014 NEI letter [12] therefore, the conclusions in the NRC's May 9 letter [14] also apply to BSEP.

In addition, the March 12, 2014 NEI letter [12] provided an attached "Perspectives on the Seismic Capacity of Operating Plants," which (1) assessed a number of qualitative reasons why the design of SSCs inherently contain margin beyond their design level, (2) discussed industrial seismic experience databases of performance of industry facility components similar to nuclear SSCs, and (3) discussed earthquake experience at operating plants.

The fleet of currently operating nuclear power plants was designed using conservative practices, such that the plants have significant margin to withstand large ground motions safely. This has been borne out for those plants that have actually experienced significant earthquakes. The seismic design process has inherent (and intentional) conservatisms that result in significant seismic margins within structures, systems and components (SSCs). These conservatisms are reflected in several key aspects of the seismic design process, including:

Page 23 of 26

ESEP Report BSEP Unit 1 and Unit 2

" Safety factors applied in design calculations

" Damping values used in dynamic analysis of SSCs

  • Bounding synthetic time histories for in-structure response spectra calculations
  • Broadening criteria for in-structure response spectra

" Response spectra enveloping criteria typically used in SSC analysis and testing applications

  • Response spectra based frequency domain analysis rather than explicit time history based time domain analysis

" Bounding requirements in codes and standards

  • Use of minimum strength requirements of structural components (concrete and steel)
  • Bounding testing requirements, and
  • Ductile behavior of the primary materials (that is, not crediting the additional capacity of materials such as steel and reinforced concrete beyond the essentially elastic range, etc.).

These design practices combine to result in margins such that the SSCs will continue to fulfill their functions at ground motions well above the SSE. The equipment items on the BSEP ESEL have sufficient design margin to withstand a RLIGM of two times the SSE based on the results of the ESEP evaluations.

In addition, per a letter from the NRC [27], BSEP screens out of performing a Seismic Risk Evaluation.

8.2 Identification of Planned Modifications Based on the collective experience of the SRT in addition to existing and newly produced HCLPF calculations, all ESEL equipment capacities are determined to meet or exceed the RLGM demands. Therefore, no modifications are required for any of the items listed on the BSEP ESEL.

8.3 Modification Implementation Schedule As noted in Section 8.2, there are no modifications for BSEP as a result of the ESEP.

8.4 Summary of Planned Actions There are no planned actions for the BSEP site as a result of the ESEP.

Page 24 of 26

ESEP Report BSEP Unit 1 and Unit 2 9.0 References

1) NRC (E Leeds and M Johnson) Letter to All Power Reactor Licensees et al.,

"Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendations 2.1, 2.3 and 9.3 of the Near-Term Task Force Review of Insights from the Fukushima Dai-lchi Accident," March 12, 2012.

2) Seismic Evaluation Guidance: Augmented Approach for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1 - Seismic. EPRI, Palo Alto, CA: May 2013. 3002000704.
3) BSEP Overall Integrated Plan (OIP) in Response to the March 12, 2012, Commission Order EA-12-049.
4) Seismic Hazard and Screening Report for Brunswick Steam Electric Plant (BSEP),

Unit Nos. 1 and 2 (Serial: BSEP 14-0028), dated March 31, 2014.

5) Not used.
6) Not used.
7) A Methodology for Assessment of Nuclear Power Plant Seismic Margin, Rev. 1, August 1991, Electric Power Research Institute, Palo Alto, CA. EPRI NP 6041-SL.
8) Methodology for Developing Seismic Fragilities, EPRI, Palo Alto, CA. June 1994, TR-103959.
9) Carolina Power and Light (CP&L), "Brunswick Nuclear Plant Individual Plant Examination for External Events Submittal," June 1995.
10) BSEP EVAL EC 91884, Fukushima NTTF 2.1 Reevaluations: Brunswick Expedited Seismic Evaluations (ESEP), Revision 0.
11) Not used.
12) Nuclear Energy Institute (NEI), A. Pietrangelo, Letter to D. Skeen of the USNRC, "Seismic Core Damage Risk Estimates Using the Updated Seismic Hazards for the Operating Nuclear Plants in the Central and Eastern United States", March 12, 2014.
13) Not used.
14) NRC (E Leeds) Letter to All Power Reactor Licensees et al., "Screening and Prioritization Results Regarding Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Seismic Hazard Re-Evaluations for Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-Ichi Accident," May 9, 2014.
15) Seismic Evaluation Guidance: Screening, Prioritization and Implementation Details (SPID) for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic. EPRI, Palo Alto, CA: February 2013. 1025287.
16) Not used.

Page 25 of 26

ESEP Report BSEP Unit 1 and Unit 2

17) BSEP EVAL EC 87912, Fukushima 2.3 Seismic Inspection Documentation - BNP Unit 2, Revision 3.
18) BSEP EVAL EC 87913, Fukushima 2.3 Seismic Inspection Documentation - BNP Unit 1, Revision 4.
19) BSEP EVAL EC 91485, Brunswick Expedited Seismic Equipment List, Revision 2.
20) Not used.
21) Not used.
22) Not used.
23) Not used.
24) Not used.
25) Carolina Power and Light (CP&L), Transmittal Letter No. BSEP 98-0145 to the USNRC from J.S. Keenan, "Brunswick Steam Electric Plant, Unit Nos. 1 and 2 Docket Nos. 50-325 and 50-324/License Nos. DPR-71 and DPR-62 Generic Letter 87-02, 'Verification of Seismic Adequacy of Mechanical and Electrical Equipment in Operating Reactors, USI A-46'," September 11, 1998.
26) Seismic Fragility Applications Guide Update. EPRI, Palo Alto, CA: December 2009.

1019200.

27) NRC (D. H. Dorman) Letter to Brunswick Steam Electric Plant (G. Hamrick),

"Brunswick Steam Electric Plant, Units 1 and 2 - Screening and Prioritization Results of Information Provided Pursuant to Title 10 of the Code of Federal Regulations Part 50, Section 50.54(f), Seismic Hazard Reevaluations for Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident (TAC NOS. MF3824 and MF3825)," September 17, 2014.

Page 26 of 26

ESEP Report BSEP Unit 1 and Unit 2 Attachment A BSEP Unit 1 and Unit 2 Combined ESEL Page Al of A8

ESEP Report BSEP Unit 1 and Unit 2 Attachment A - BSEP Unit I and Unit 2 Combined ESEL 0020 1-H21-PO17 RCIC INSTRUMENT RACK N/A N/A E51-PSH-NO12D 0022 1-E51-F029 RCIC SUPPRESSION POOL SUCTION VALVE TO THE RCIC PUMP CLOSED OPEN 0024 1-E51-F046 RCIC COOUNG WATER SUPPLY VALVE CLOSED OPEN 0026 I-E51-C002-BAROM-COND RCIC BAROMETRIC CONDENSER N/A N/A 0028 1-E51-C002-VAC-PMP RCIC TURBINE VACUUM PUMP N/A N/A 0030 I-E51-F019 RCIC MIN FLOW BYPASS TO SUPPRESSION POOL VALVE CLOSED OPEN 0032 1-E51-F045 RCIC TURBINE STEAM SUPPLY VALVE CLOSED OPEN 0034 1-E51-V9 RCIC TURBINE GOVENOR VALVE OPEN VARIES (THROTTLED) 0036 I-E51-STM-EXH-DRN-POT RCIC EXHAUST DRAIN POT N/A N/A Contains I-ESI-PDT-NO18, l-ESI-PS-NO19B, I-Page A2 of A8

ESEP Report BSEP Unit l and Unit 2 Attachment A- BSEP Unit l and Unit 2 Combined ESEL 0062 2-H21-P035 RCIC LEAK DETECTION INSTRUMENT RACK N/A N/A 2-E51-PS-NO19C 0064 2-ES1-F025 RCIC SUPP DRAIN POT INBD ISOLATION VLV ESR 98-00330 OPEN OPEN 006 1-B2l-FOl3B PRIMARY STEAM UNE 'A SAFETY REUEF VALVE CLOSED VARIES 0068 1-B21-FO13D PRIMARY STEAM UNE W8.SAFETY REUEF VALVE VARS 0070 1-B21-FO13F PRIMARY STEAM UNE 'C' SAFETY REUEF VALVE CLOSED VARIES 00728 1-B21-FO13H PRIMARY STEAM UNE 'D' SAFETY REUEF VALVE CLOSED VARIES 0074 1-B21-FO13K PRIMARY STEAM UNE 'C' SAFETY REUEF VALVE CLOSED VARIES 007 1-B21-AOO3A AIR ACCUMULATOR FOR B21-FOl3A N/A N/A 0078 l-B21-AOO3C AIR ACCUMULATOR FOR B21-FO13C N/A N/A 0080 1-B21-A003E AIR ACCUMULATOR FOR B21-FO13E N/A N/A _

Page A3 of A8

ESEP Report BSEP Unit I and Unit 2 Attachment A - BSEP Unit 1 and Unit 2 Combined ESEL Page A4 of A8

ESEP Report BSEP Unit l and Unit 2 Attachment A - BSEP Unit 1and Unit 2 Combined ESEL

1. I I ITR 1-8.21-1UR16O4-1BX1 1-CAC-PI-3341, and 1-S 1I~,4-ZACJ-aU1O, I ITR-778, 2-B21-U-R604-BX, 2-CAC-Pl-3341, and 2-D152 1-H21-P037 RCIC LEAK DET SYS A INSTRUMENT RACK lAvailable Available INOIZC 0154 l-B21-LTM-NO31B-l B-21-LT-NO31B Master Trn Unit Available Available Contained in 1-XU-64 D156 l-BZ1-LTMV-NO31LD-l B-21-LT-N0310) Mas5ter Tri Unit Available Available Contained in l-XU-64 Page AS of A8

ESEP Report BSEP Unit 1 and Unit 2 Attachment A - BSEP Unit 1 and Unit 2 Combined ESEL Page A6 of AS

ESEP Report BSEP Unit I and Unit 2 Attachment A - BSEP Unit 1 and Unit 2 Combined ESEL E51-PDTS-N018-2, 2-B21-LTM-NO31B-1, 2-B21-LTM-NO31D-1, 2-821-NVT-1-B, and 2-B21-PTM-0192 2-XU-64 TRIP CAUIBRATION CABINET-ECCS DIVISION II. Available Available N045D 0194 2-ES1-PDT-NO18 RCIC STEAM UNE HI FLOW DIFF PRESS.. TRANSMITTER Available Available Contained in 2-H21-P038 0196 2-E51-PS-NO19B RCIC TURB STEAM SUPPLY LOW PRESS SW ...PM 84-184 Available Available Contained in 2-H21-P038 0198 2-E51-PSH-NO12B RCIC TURB EXH DIAPHRAGM HI PRESS SW ... PM 84-184 Available Available Contained in 2-H21-P017 0200 1-B21-U-R604-BX REMOTE REACTOR WATER LEVEL IND Available Available Located inside 1-IR-RB-4 Contains 1-B321-1-T-NO31B], 1-B21-LT-NO31D, and 0202 1-H21-POO5 RX PROT & NSS SYSTEM INSTRUMENT RACK Available Available 1-B21-LT-N0268 0204 I-B21-ES-4051 Ell-FT-3338 & B21-LT-NO17D-3 CKTS ... AND OTHER ASCA INSTRUMENTS Available Available Contained in 1-IR-RB-4 0206 1-B21-PT-NO45D REACTOR VESSEL HI PRESS TRANSMITTER Available Available Contained in 1-H21-PO05-002 0208 1-H21-POOS-002 REACTOR PROTECTION RACK Available Available Contains 1-B21-PT-NO45D 0210 1-CAC-PT-3341 DRYWELL PRESSURE TRANSMITTER Available Available 0212 1-CAC-TE-778-6 TORUS WATER TEMPERATURE ELEMENT Available Available 0214 I-CAC-LT-3342 SUPPRESSION POOL LEVEL TRANSMITTER Available Available Contained in 1-H21-P022-01 0216 2-B21-U-R604-BX FOR RPV WATER LEVEL INDICATION......AT THE REMOTE SHUTDOWN PANEL Available Available Located inside 2-IR-RB-4

-H21POO5Contains 2-R21-LT-NO26B, 2-B21-LT-NO31B, and 0218 2-H21-P005 RX PROT & NSS SYSTEM INSTRUMENT RACK Available Available 2-B21-LT-NO31D 0220 2-B21-FS40S1 POWER SUPPLY FOR VARIOUS ASCA INSTR Available Available Contained in 2-1R-RB-4 0222 2-B21-PT-N04SD REACTOR HIGH PRESSURE TRANSMITTER Available Available Contained in 2-H21-POOS-(E)2 0224 2-H21-POOS-002 REACTOR PROTECTION RACK Available Available Contains 2-B21-PT-NO45D 0226 2-CAC-PT-3341 DRYWELL PRESSURE TRANSMITTER Available Available 0228 2-LAC-TE-778-6 TORUS WATER TEMPERATURE ELEMENT Available Available Page A7 of A8

ESEP Report BSEP Unit 1 and Unit 2 Attachment A - BSEP Unit 1 and Unit 2 Combined ESEL 10238 1 2-H21-P004 IRX PROTECTION & NSSS INSTR RACK. IAvailable lAvailable IContains 2-821-LT-NO31A and 2-B21-LT-NO31C I Page A8 of A8

ESEP Report BSEP Unit 1 and Unit 2 Attachment B ESEP HCLPF Values and Failure Modes Tabulation, BSEP Units 1 and 2 Page B1 of B6

ESEP Report BSEP Unit I and Unit 2 Attachment B - ESEP HCLPF Values and Failure Modes Tabulation, BSEP Unit 1 and Unit 2 Page B2 of B6

ESEPReport BSEPUnit I and Unit 2 Attachment B- ESEPHCLPFValues and Failure Modes Tabulation, BSEPUnit I and Unit 2

- I Page B3of BG

ESEP Report BSEP Unit 1 and Unit 2 Attachment B - ESEP HCLPF Values and Failure Modes Tabulation, BSEP Unit 1 and Unit 2 Page B4 of B6

ESEPReport BSEPUnit 1 and Unit 2 Attachment B- ESEPHCLPFValues and Failure Modes Tabulation, BSEPUnit 1 and Unit 2 1 -ES1-POT1-018-2 E51-PDT-N017 SLAVETRIP UNIT.. Aalbe Available I-XU-Msor64l 0%

16 -E51-P-40N19D) RCICTURB STEAMSUPPLYLOW PRESS SW .. PM 84-184 Aalbe Available 1-H21-P039 Screened >RLGM 10 lEIPHN1DRCIC TURB EXHDIAPHRAGM HI PRESS SW. .PM 84-184 Available Available 1-.H21-P01 7 Scend RG 12 2-B21-PS-1-A ECSDVITI AB A W UPYAv~ailalble Available 2-XU-63 Screened >RLGM 14 2-E51-PDTM-N017-1 ESI-PDT-N017 MASTER TRIPUNIT. ***Available Avatlable 2-XU-6£3 screened *P.LGM 17 -ESl-PGTS-N017-2 E51-PDT-.N017 SLAVETRIPUNIT.,. Available Available 2-XU-63 Screened >RLGM-q 17 -E51-PE-N019C RQCITURB STEAMSUPPLYLOW PRESS SW .. PM 84-184 A-aiable Available 2-H21-P035 Screened >RLGM IO 2-ESl-PSH-N0,12C RCICTURBEXHDIAPHRAGM HI PRESS SW .,.PM 84-194 Available Available 2-H21-PO37 Screenied >RUGM lei -B21-TM-N7 A1B1L-O1 ATRTI NT vial vial -U6 oee NG 18 -B21-LTM-N031A-1 B21-LT-N031A MASTERTRIP UNIT. Available Available 2-XU-63 Screened >RLGM 18 -B21-LT-.N031A REACTORVESSEL LOW WATER LEVEL)q*MTR. **Available Available 2-/-21-POO-4 HOST ANC140RAGE 19 1-821-LT-N031C REACTORVESSEL LOW WATER LEVEL XMTR. Available 2-H2*A-dablae I-POO4 140ST ANCHORAGE037 19 -B321-INVT-1-B B21-PS-1-6 DC INVERTER. Available Available 2-XU-64 Screened >RLGM 19 -XU-,&4 TRIP CALIBRATION CAB!NET-ECCS DIVISION 11. Available Available Screened RLGM 194 E51-PDT-N013 RCICSTEAM LINEH] FILOWDIFFPRESS.. TRANSMITTER Available Available 2-H21-P'038 Screened >RLGM 19 2-E51-PS-NO19B RIC TURB STEAMSUPPLYLOW PRESS SW _,,PM84-18,4 Available Available 2-H21-P03,8 Screened >RLGM M 2-E51-PSH-NO1.2B RCICTURB EXHDIAPHRAGM HI PRESS SW .. PM 84-184 Available Available 2-H214P017 Screened >RLG 20 1-B21-L-.R604-BX REMO TEREACTOR WATER LEVELINC) Available Available 1-1R-RB.4 HOST ANCHORAGE 0.3111

-H21-1`005 10 RXPROT & NSS S;YSTEM INSTRUMENT RACK Available Available ANCHORAGE W.371 24 11-B21-ES-4051 El14=T-3338 & B21--N1.7 0-3 CKTS_.AND OTHER AKCAINSTRUMENTS A-aiable Available 1-4R-RB-4 HOST ANCHORAGE 031 26 1-821-PT-NO45D REAC70R VESSEL HI PRESS TRANSMITTER Available Available 1-H21-F,005-002 HOSTANCHORAGE 0-171 29 14-1-21-1=005-002 REACTORPROTECTION RACK ***Available Available ACOAE07 21 -C.AC-PT-3341 ORYWELL PRESSURE TRANSMITTER Available AvialeSrendýLGM 21 -CAC-TE-778-6 TORUS WATER TEMPERATURE ELEMENT Available Available Screewed >RUGM 21 -C-AC-LT-3342 SUPPRESSION POOL LEVELTRANSMITTER Available Available 1-H21-P022-01 Sceee >RLGM 26 2-B211-U-R604-BX -FOR RPV WATER LEVELINDICATION .... ATTHE REMOTE! SHUTDOWN PANEL Available Available 2-1R-RB-4 HOSTANCHORAGE 03 29 2-H 21.-.P00S RXPROT & NSSSYSTEMINSTRUMENT RACK Available Available ANCHORAGE 0. 7g[

.!0 2-B21-.ES-4051 POWER SUPPLYFOR VARIOUS ASLAINSTR IAvailable Available 24f-1RO-R4 IiS ANHOAE I If Page BS of 86

ESEP Report BSEP Unit I and Unit 2 Attachment B - ESEP HCLPF Values and Failure Modes Tabulation, BSEP Unit I and Unit 2 Page B6 of B6

ESEP Report BSEP Unit 1 and Unit 2 Attachment C Summary of FLEX Seismic Implementation Strategies Figures Page Cl of C7

ESEP Report BSEP Unit 1 and Unit 2 Attachment C - Summary of FLEX Seismic Implementation Strategies Figures a a ToROMdwest Figure 1 Reactor Core Isolation Cooling Page C2 of C7

ESEP Report BSEP Unit 1 and Unit 2 Attachment C - Summary of FLEX Seismic Implementation Strategies Figures To.

CST Figure 2 Fuel Pool Cooling Page C3 of C7

ESEP Report BSEP Unit 1 and Unit 2 Attachment C - Summary of FLEX Seismic Implementation Strategies Figures Figure 3 Reactor Water Cleanup Page C4 of C7

ESEP Report BSEP Unit l and Unit 2 Attachment C - Summary of FLEX Seismic Implementation Strategies Figures Figure 4 IAN / RNA/ Backup Nitrogen Page C5 of C7

ESEP Report BSEP Unit 1 and Unit 2 Attachment C - Summary of FLEX Seismic Implementation Strategies Figures R.

FLEX4* HoseVa F050A Pu17AAo" PumpFOO. F F031A4 FOM Fii*4B RPRmW Pum Fu pum Figure 5 Residual Heat Removal Page C6 of C7

ESEP Report BSEP Unit 1 and Unit 2 Attachment C - Summary of FLEX Seismic Implementation Strategies Figures RxBLDGRoof nd he AC-216 CAC-7, R~sCAC-V216 Figure 6 Hardened Wetwell Vent Page C7 of C7

Retrieved from "https://kanterella.com/w/index.php?title=BSEP_14-0131,_Expedited_Seismic_Evaluation_Process_Report_in_Response_to_10_CFR_50.54(f)_Request_for_Information_Regarding_Recommendation_2.1_of_the_Near-Term_Task_Force_Review_of_Insights_from_the_Fukushima_Dai-lchi_Accident&oldid=2450335"