ML19205A341

NRC Staff Initial Written Statement of Position

ML19205A341
Person / Time
Site:	Seabrook
Issue date:	07/24/2019
From:	Naber A, Jennifer Scro, Jeremy Wachutka NRC/OGC
To:	Atomic Safety and Licensing Board Panel
SECY RAS
References
50-443-LA-2, ASLBP 17-953-02-LA-BD01, RAS 55103
Download: ML19205A341 (79)

Text

UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In the Matter of NEXTERA ENERGY SEABROOK, LLC Docket No. 50-443-LA-2 (Seabrook Station, Unit 1)

NRC STAFF INITIAL WRITTEN STATEMENT OF POSITION Jeremy L. Wachutka Anita Ghosh Naber Jennifer Scro Counsel for NRC Staff July 24, 2019

TABLE OF CONTENTS PAGE TABLE OF AUTHORITIES ......................................................................................................... iv INTRODUCTION ........................................................................................................................1 BACKGROUND ..........................................................................................................................2 I. ASR at Seabrook .............................................................................................................3 A. Initial Discovery of ASR and the Staff Response ..................................................3 B. The 2012 Confirmatory Action Letter....................................................................7 C. Deviation from the Reactor Oversight Process and Increased Oversight ............. 9 D. The Staff Inspections of the LSTP......................................................................12 E. The Staff Inspections of the Implementation of the ASR Expansion Monitoring Program at Seabrook .......................................................................15 II. The ASR License Amendment Request ........................................................................18 A. The ASR Expansion Monitoring Program ...........................................................21 B. The Structure Deformation Monitoring Program .................................................22 III. C-10s Challenge to the ASR License Amendment Request.......................................... 24 IV. The Staffs Safety Evaluation of the ASR License Amendment Request ....................... 25 V. The Independent Review of the LSTP by RES ..............................................................26 VI. The Independent Review of ASR at Seabrook by the ACRS ......................................... 27 DISCUSSION ........................................................................................................................28 I. Legal Standards ............................................................................................................28 II. NextEra Has Provided Reasonable Assurance that, with the License Amendment, as Conditioned, Seabrook Will Continue to Meet NRC Requirements ........................... 32 A. The Conduct of the LSTP Provided Reasonable Assurance that its Data Are Representative and/or Bounding of the Progression of ASR at Seabrook.... 32

i. The LSTP Was Representative and/or Bounding ................................... 34 ii. The Anchor Test Program Was Representative and/or Bounding ........... 36

ii iii. The Shear Test Program Was Representative and/or Bounding ............ 37 iv. The Reinforced Anchorage Test Program Was Representative and/or Bounding .....................................................................................38

v. The Additional Determinations Made Based, in Part, on the LSTP Were Representative and/or Bounding ...................................................39 vi. The Instrumentation Test Program Provided Reasonable Assurance of Selection of Appropriate Instrument for Measuring Through-Thickness Expansion..............................................................................41 B. NextEra Appropriately Used the LSTP Data to Develop the Seabrook ASR Expansion Monitoring Program ..........................................................................43 III. C-10s Arguments Do Not Demonstrate that, with the License Amendment, as Conditioned, Seabrook Will Not Continue to Meet NRC Requirements.......................... 45 A. C-10s Argument Regarding the Representativeness of the LSTP Concrete Is Not Persuasive ...............................................................................................46

i. C-10 Argument .......................................................................................46 ii. Staff Response .......................................................................................46 B. C-10s Argument Regarding Testing to Maximum Expansion Is Not Persuasive ...............................................................................................48

i. C-10 Argument .......................................................................................48 ii. Staff Response .......................................................................................48 C. C-10s Arguments Regarding the Representativeness of the LSTP Test Specimens Are Not Persuasive..........................................................................49

i. C-10 Arguments Regarding Modeling .....................................................49 ii. Staff Response Regarding Modeling ......................................................50 iii. C-10 Arguments Regarding the Shear Test Program ............................. 51 iv. Staff Response Regarding the Shear Test Program ............................... 52

v. C-10 Arguments Regarding Assumptions ...............................................54 vi. Staff Response Regarding Assumptions ................................................ 54 vii. C-10 Arguments Regarding SE Statements ........................................... 55

iii viii. Staff Response Regarding SE Statements ............................................. 55 ix. C-10 Arguments Regarding CI/CCI ........................................................57

x. Staff Response Regarding CI/CCI ..........................................................57 D. C-10s Arguments Regarding the Structure Deformation Monitoring Program Are Not Within the Scope of this Proceeding......................................................62 E. C-10s Arguments Regarding the Structure Deformation Monitoring Program Are Not Persuasive ............................................................................................66

i. C-10 Argument Regarding Linear Elastic Analysis ................................. 67 ii. Staff Response Regarding Linear Elastic Analysis ................................. 67 iii. C-10 Argument Regarding Probabilistic Based Analysis ......................... 69 iv. Staff Response Regarding Probabilistic Based Analysis ........................ 69 F. C-10s Argument Regarding Peer Review and In-House Expertise Is Not Persuasive ...............................................................................................70 CONCLUSION ..........................................................................................................................72

iv TABLE OF AUTHORITIES Page ADMINISTRATIVE DECISIONS Commission AmerGen Energy Company, LLC (Oyster Creek Nuclear Generating Station),

CLI-09-7, 69 NRC 235 (2009) ........................................................................................ 31 n. 153 Crow Butte Res., Inc. (In Situ Leach Facility, Crawford, Nebraska),

CLI-15-17, 82 NRC 33 (2015) ........................................................................................ 31 n. 155 Duke Power Co. (Catawba Nuclear Station, Units 1 and 2),

CLI-83-19, 17 NRC 1041 (1983) .................................................................................... 31 n. 152 Entergy Nuclear Operations, Inc. (Palisades Nuclear Plant),

CLI-15-22, 82 NRC 310 (2015) .................................................................................................29 Entergy Nuclear Generation Co. (Pilgrim Nuclear Power Station),

CLI-10-11, 71 NRC 287 (2010) ...................................................................................... 62 n. 330 NextEra Energy Seabrook, LLC (Seabrook Station, Unit 1),

CLI-12-5, 75 NRC 301 (2012) ........................................................................................ 62 n. 330 Atomic Safety and Licensing Appeal Board Consumers Power Co. (Midland Plant, Units 1 and 2),

ALAB-283, 2 NRC 11 (1975) .......................................................................................... 31 n. 152 Pacific Gas and Electric Co. (Diablo Canyon Nuclear Power Plant, Units 1 and 2),

ALAB-763, 19 NRC 571 (1984) ...................................................................................... 31 n. 154 Tennessee Valley Authority (Hartsville Nuclear Plant, Units 1A, 2A, 1B, and 2B),

ALAB-463, 7 NRC 341 (1978);

reconsideration denied, ALAB-467, 7 NRC 459 (1978) .................................................. 31 n. 154 Atomic Safety and Licensing Board NextEra Energy Seabrook, LLC (Seabrook Station, Unit 1),

LBP-17-7, 86 NRC 59 (2017) ........................................................................ 24 n. 116, 62 n. 331 STATUTES Atomic Energy Act of 1954, as amended, § 29, Advisory Committee on Reactor Safeguards; composition; tenure; duties; compensation (42 USC § 2039) (Nov. 10, 1998). ................................................................. 27 n. 131, 71 n. 380

v REGULATIONS 10 C.F.R. § 2.1207(a)(1) .............................................................................................................1 10 C.F.R. Part 50, Appendix A ..................................................................................................29 10 C.F.R. Part 50, Appendix B ...................................................................................... 30, 31, 32 10 C.F.R. § 50.40(a) .................................................................................................................28 10 C.F.R. § 50.57(a)(3) ............................................................................................ 29, 48 n. 245 10 C.F.R. § 50.90......................................................................................................................28 10 C.F.R. § 50.92(a) ................................................................................................ 28, 47 n. 244 FEDERAL REGISTER NOTICES NextEra Energy Seabrook, LLC; Seabrook Station, Unit No. 1, License Renewal and Record of Decision; Issuance, 84 Fed. Reg. 9563 (March 15, 2019) ............. 17 n. 77, 26 n. 122 Applications and Amendments to Facility Operating Licenses and Combined Licenses Involving Proposed No Significant Hazards Considerations and Containing Sensitive Unclassified Non-Safeguards Information and Order Imposing Procedures for Access to Sensitive Unclassified Non-Safeguards Information, 82 Fed. Reg. 9,601 (Feb. 7, 2017) ................................... 23 n. 112 MISCELLANEOUS ACRS Membership, https://www.nrc.gov/about-nrc/regulatory/advisory/acrs/membership.html (last visited July 24, 2019) .............................................................................................. 71 n. 382 Letter from Paul O. Freeman, Site Vice President, NextEra, to NRC, Seabrook Station Application for Renewed Operating License (LAR) (May 25, 2010) ..... 4 n. 11 Letter from Richard Plasse, NRC, to Paul Freeman, NextEra, Request for Additional Information Related to the Review of the Seabrook Station License Renewal Application -

Aging Management Programs (Nov. 2010 RAI) (Nov. 18, 2010) .......................... 4 n. 12, 6 n. 21 Letter from Paul O. Freeman, NextEra, to NRC Document Control Desk, Seabrook Station, Response to Request for Additional Information, NextEra Energy Seabrook License Renewal Application, Aging Management Programs (Dec. 2010 Response to RAI) (Dec. 17, 2010) ................................................................... 4 n. 12 Safety Evaluation Report Related to the License Renewal of Seabrook Station, Docket No. 50-443, NextEra Energy Seabrook, LLC (LRA SER) (Sept. 28, 2018) ................. 18 n. 76, 22 n. 102

UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In the Matter of NEXTERA ENERGY SEABROOK, LLC Docket No. 50-443-LA-2 (Seabrook Station, Unit 1)

NRC STAFF INITIAL WRITTEN STATEMENT OF POSITION INTRODUCTION In accordance with 10 C.F.R. § 2.1207(a)(1) and the Atomic Safety and Licensing Boards Order dated February 15, 2018, 1 the U.S. Nuclear Regulatory Commission Staff files this initial written statement of position supporting its issuance of a license amendment, as conditioned, to NextEra Energy Seabrook, LLC. The Staff issued this license amendment because, it part, it found that the conduct of the large-scale test program (LSTP) commissioned by NextEra provided reasonable assurance that its data were representative and/or bounding of the progression of alkali-silica reaction (ASR) (also known as alkali-aggregate reaction (AAR))

at Seabrook Station, Unit No. 1. The Staff also found that NextEra had appropriately used these LSTP data to develop the ASR expansion monitoring program proposed as part of the license amendment. The Staffs statement of position is supported by the written testimony and affidavits of Angela Buford, Bryce Lehman, and George Thomas (Exhibit NRC001) 2 and the 1

Memorandum and Order (Revised Scheduling Order) (Feb. 15, 2018) (ADAMS Accession No. ML18046A985).

2 The statements of professional qualifications for Angela Buford, Bryce Lehman, and George Thomas are Exhibits NRC002, NRC003, and NRC004, respectively.

exhibits cited therein. The written testimony and affidavit of Jacob Philip (Exhibit NRC005) 3 and the exhibits cited therein explains the separate, independent review of the LSTP by the NRC Office of Nuclear Regulatory Research (RES). For the reasons set forth below and in the supporting testimonies, the Board should uphold the Staffs determination that NextEra has provided reasonable assurance that, with the license amendment, as conditioned, Seabrook will continue to meet NRC requirements.

BACKGROUND This proceeding concerns NextEras August 1, 2016 license amendment request (LAR) to adopt a methodology to account for the impacts of ASR on seismic Category I 4 reinforced concrete structures at Seabrook. 5 ASR is a chemical reaction in concrete that occurs in the 3

The statement of professional qualifications for Jacob Philip is Exhibit NRC006.

4 Seismic Category I structures, systems, and components include those necessary to control the release of radioactive material or otherwise mitigate the consequences of an accident. See Exhibit NRC088, Regulatory Guide (RG) 1.29, Seismic Design Classification for Nuclear Power Plants, Rev. 5 at 5 (July 2016) (ML16118A148).

5 Exhibit INT010/Exhibit NRC089, License Amendment Request 16-03, Revise Current Licensing Basis to Adopt a Methodology for the Analysis of Seismic Category I Structures with Concrete Affected by Alkali-Silica Reaction (Aug. 1, 2016) (ML16216A240 (nonproprietary) and ML16216A244 (proprietary),

respectively) (Original LAR) (The Staff does not cite Exhibit INT011 because it includes highlighting that is not a part of the original document).

NextEra supplemented the Original LAR on September 30, 2016, October 17, 2017, December 11, 2017, and June 7, 2018. Exhibit NRC010, Letter from Ralph A. Dodds III, NextEra, to NRC Document Control Desk, Seabrook Station, Supplement to License Amendment Request 16-03, Revise Current Licensing Basis to Adopt a Methodology for the Analysis of Seismic Category I Structures with Concrete Affected by Alkali-Silica Reaction (Sept. 30, 2016) (ML16279A048) (Sept. 2016 LAR Supplement); Exhibit NRC013, Letter from Eric McCartney, NextEra, to NRC Document Control Desk, Seabrook Station, Response to Request for Additional Information Regarding License Amendment Request 16-03 Related to Alkali-Silica Reaction (Oct. 3, 2017) (ML17277A337) (Oct. 2017 LAR Supplement); Exhibit NRC014, Letter from Eric McCartney, NextEra, to NRC Document Control Desk, Seabrook Station, Response to Request for Additional Information Regarding License Amendment Request Related to Alkali-Silica Reaction (Dec.

11, 2017) (ML17345A641) (Dec. 2017 LAR Supplement); Exhibit NRC015, Letter from Christopher Domingos, NextEra, to NRC Document Control Desk, Seabrook Station, Response to Request for Additional Information Regarding License Amendment Request 16-03 (June 7, 2018) (ML18158A540)

(June 2018 LAR Supplement) (enclosure 3 of this submittal is Exhibit INT023 and enclosure 4 is Exhibit INT024). Separately, on May 18, 2018, in updating its license renewal application for Seabrook, NextEra

presence of moisture where alkalis, usually from the cement, react with certain reactive types of silica in the aggregate. 6 This reaction produces an alkali-silica gel that can absorb water and expand to cause micro-cracking of the concrete. 7 Excessive expansion of the gel may lead to significant cracking that may change the mechanical material properties of the concrete. 8 NextEra submitted the LAR in response to the discovery of ASR at Seabrook.

I. ASR at Seabrook Although the LAR was submitted in 2016, the issue of ASR at Seabrook significantly predated this. 9 This section discusses, in chronological order, the events that informed the Staffs review of the LAR.

A. Initial Discovery of ASR and the Staff Response In June 2009, in preparation for NextEras submission of a license renewal application for Seabrook, NextEra initially identified pattern cracking typical of ASR at Seabrook in the B provided revised versions of MPR reports previously submitted as LAR supplements. Exhibit NRC016, Letter from Eric McCartney, NextEra, to NRC Document Control Desk, Seabrook Station Revised Structures Monitoring Aging Management Program (May 18, 2018) (ML18141A785) (May 2018 MPR Reports Update) (enclosure 2 of this letter is INT017; enclosure 4, MPR-4153, Rev. 3 (nonproprietary) is INT018-R; enclosure 5, MPR-4273, Rev. 1 (nonproprietary) is INT019-R; enclosure 6, MPR-4153, Rev. 3 (proprietary) is INT020; Enclosure 7, MPR-4273, Rev. 1 (proprietary) is INT020).

Collectively, the Original LAR, all supplements, and the May 18, 2018 MPR report revisions, plus all enclosures and attachments, constitute the LAR.

6 Exhibit NRC001, Staff Testimony at A.5; Exhibit INT024/Exhibit INT025, Safety Evaluation by the Office of Nuclear Reactor Regulation Related to Amendment No. 159 to Facility Operating License No. NPF-86, encl. 2 at 5 (Mar. 11, 2019) (ML18204A291 (nonproprietary) and ML18204A282 (proprietary),

respectively) (Safety Evaluation (SE)); Exhibit NRC060, NRC Information Notice 2011-20: Concrete Degradation by Alkali-Silica Reaction, at 2 (Nov. 18, 2011) (ML112241029) (IN-2011-20).

7 Exhibit NRC001, Staff Testimony, at A.5; Exhibit INT024, SE encl. 2 at 5; Exhibit NRC068, IN-2011-20.

8 Exhibit NRC001, Staff Testimony, at A.5, A.7; Exhibit INT024, SE encl. 2 at 5; Exhibit NRC068, IN-2011-

20. The mechanical material properties of concrete include compressive strength, elastic modulus, tensile strength, shear strength, and flexural strength. Exhibit NRC001 at A.6.

9 Exhibit NRC001, Staff Testimony at A.10.

Electrical Tunnel, and, subsequently, in several other seismic Category I structures. 10 After NextEra submitted its license renewal application on May 25, 2010, 11 the Staff observed, during license renewal audit walkdowns, degradation in concrete structures exposed to groundwater, including the Containment Enclosure Building. 12 In August 2010, NextEra confirmed the presence of ASR in concrete in below-grade walls of several Seabrook structures through petrographic analysis of concrete cores removed from the affected plant structures. 13 In addition to the B Electrical Tunnel, NextEra confirmed ASR in the Residual Heat Removal (RHR) and Containment Spray (CS) Equipment Vault, the Emergency Feedwater Pumphouse, the Diesel Generator Building, and the Containment Enclosure Building. 14 10 Exhibit NRC001, Staff Testimony at A.10; Exhibit INT024, SE encl. 2 at 5; see Exhibit NRC019, Confirmatory Action Letter, Seabrook Station, Unit 1 - Information Related to Concrete Degradation Issues, at 1 (May 16, 2012) (ML12125A172) (CAL); Exhibit NRC078, Letter from Paul O. Freeman, NextEra, to NRC, Seabrook Station Response to Confirmatory Action Letter, encl. 1 at 1 (unnumbered)

(May 24, 2012) (ML12151A396) (NextEra Response to CAL).

11 Letter from Paul O. Freeman, Site Vice President, NextEra, to NRC, Seabrook Station Application for Renewed Operating License (May 25, 2010) (ML101590099) (LRA).

12 Exhibit NRC001, Staff Testimony at A.10; Letter from Richard Plasse, NRC, to Paul Freeman, NextEra, Request for Additional Information Related to the Review of the Seabrook Station License Renewal Application (TAC No ME4028) - Aging Management Programs, encl. at 10-11, 16 (Nov. 18, 2010)

(ML103090558) (Nov. 2010 RAI); Letter from Paul O. Freeman, NextEra, to NRC Document Control Desk, Seabrook Station, Response to Request for Additional Information, NextEra Energy Seabrook License Renewal Application, Aging Management Programs, encl. 1 at 26, 32-33 (Dec. 17, 2010)

(ML103540534) (Dec. 2010 Response to RAI). In its response to the Staffs Request for Additional Information (RAI), NextEra stated that it would perform confirmatory testing and evaluation of the Containment Enclosure Building to determine whether the observed concrete degradation was due to ASR. Dec. 2010 Response to RAI, encl. at 31-33. NextEra subsequently confirmed the presence of ASR in the Containment Enclosure Building. Exhibit NRC079, Enclosure 2 to SBK-L-12106, The Evaluation, Impact of ASR on Concrete Structures and Attachments, § 3.1.2 at 20 (May 2012)

(ML12151A397) (Interim Structural Assessment).

13 Exhibit INT024, SE, encl. 2 at 5; Exhibit INT010, LAR, at 8 of 73.

14 See Exhibit NRC079, Interim Structural Assessment, § 3.1.1 at 19-20 (stating that petrographic examination confirmed the presence of ASR in the B Electrical Tunnel, the RHR & CS Equipment Vault, the Emergency Feedwater Pumphouse, the Diesel Generator Building, and the Containment Enclosure Building).

In September 2010, NextEra initiated prompt operability determinations to assess the safety significance of the ASR issue and the basis for continued plant operation. 15 The prompt operability determinations concluded that although the ASR-affected structures did not conform to Seabrooks licensing basis (because ASR was not accounted for in the licensing basis), the structures were still operable in that they would maintain structural integrity for design basis loads and load combinations for normal, accident, and environmental extreme conditions. 16 As NextEra collected more information on the presence of ASR at Seabrook and incorporated revised analytical techniques, it revised the prompt operability determinations. 17 In October 2010, the Staff conducted a nine-day onsite audit of NextEras aging management programs in connection with the license renewal application. 18 The audit report noted that Staff had found that groundwater migrated into the annular space between the concrete enclosure building and concrete containment and that [t]he bottom 6 feet of the concrete containment wall was in contact with the groundwater for a long period of time. 19 After noting that ASR-related cracking had been observed in concrete structures at Seabrook, 15 Exhibit NRC025, Letter from Christopher G. Miller, NRC, to Kevin Walsh, NextEra, Seabrook Station, Unit No. 1 - Confirmatory Action Letter Follow-up Inspection - NRC Inspection Report 05000443/2012009, Enclosure, Inspection Report No. 0500044312012009, at 1 (Dec. 3, 2012) (ML12338A283) (2012 CAL Follow-up Inspection).

16 Id., encl. at 4; Exhibit INT024, SE, encl. 2 at 6.

17 Exhibit NRC001, Staff Testimony at A.10; Exhibit NRC025, 2012 CAL Follow-up Inspection, encl. at 1; see Exhibit NRC033, Letter from Mel Gray, NRC, to Dean Curtland, NextEra, Seabrook Station, Seabrook Station - Inspection Report 05000443/2016008 Related to Alkali-Silica Reaction Affects on Safety-Related Concrete Structures and Notice of Violation, encl. 2 at 1-2 (May 6, 2016)

(ML16127A155) (May 2016 Inspection Report).

18 Exhibit NRC020, Letter from Richard A. Plasse, NRC, to Paul Freeman, NextEra, Audit Report Regarding the Seabrook Station License Renewal Application (TAC Number ME4028), encl. at 1 (Mar.

21, 2011) (ML110280424) (Mar. 2011 Audit Report).

19 Id. encl. at 65.

including the containment enclosure building, the audit report stated that the Staff needed further information to evaluate the impact of ASR on the Seabrook aging management programs. 20 Between November 2010 and June 2011, the Staff sent NextEra several requests for additional information (RAIs) regarding NextEras license renewal application and, specifically, for further information on ASR at Seabrook. 21 In addition, in 2011, the Staff conducted three inspections of Seabrook that included a review of NextEras prompt operability determinations related to ASR-affected structures. 22 On January 20, 2012, the Staff completed an inspection to assess NextEras progress in developing a corrective plan and schedule to address the ASR degradation issue. 23 This inspection included a review by NRC regional inspectors and headquarters experts of NextEras prompt operability determinations. 24 After this inspection, the Staff found that (1) NextEra used 20 Id. encl. at 65-66; 74-75.

21 See, e.g., Nov. 2010 RAI, encl. at 10; Letter from Richard A. Plasse, NRC, to Paul Freeman, NextEra, Request for Additional Information Related to the Review of the Seabrook Station License Renewal Application, encl. at 2-3 (Mar. 17, 2011) (ML110350630); Letter from Richard A. Plasse, NRC, to Paul Freeman, NextEra, Request for Additional Information for the Review of the Seabrook Station License Renewal Application, encl. at 2-3, 5 (June 29, 2011) (ML11178A338).

22 Exhibit NRC001, Staff Testimony at A.10; Exhibit NRC021, Letter from Arthur L. Burritt, NRC, to Paul Freeman, NextEra, Seabrook Station, Unit No. 1 - NRC Integrated Inspection Report 05000443/2011002 (May 12, 2011) (ML111330689); Exhibit NRC022, Letter from Richard J. Conte, NRC, to Paul Freeman, NextEra, NextEra Energy Seabrook - NRC License Renewal Inspection Report 05000443/2011007 (May 23, 2011) (ML111360432); Exhibit NRC023, Letter from Arthur L. Burritt, NRC, to Paul Freeman, NextEra, Seabrook Station, Unit No. 1 - NRC Integrated Inspection Report 05000443/2011003 (Aug. 12, 2011) (ML112241543).

23 Exhibit NRC001, Staff Testimony at A.10; Exhibit NRC024, Letter from Christopher G. Miller, NRC, to Paul Freeman, NextEra, Seabrook Station - NRC Inspection Report 05000443/2011010 Related to Alkali-Silica Reaction Issue in Safety Related Structures, at 1 (Mar. 26, 2012) (ML120480066) (Mar.

2012 Inspection Report).

24 Exhibit NRC001, Staff Testimony at A.10; Exhibit NRC024, Mar. 2012 Inspection Report at 1.

conservative load factors to ensure that there was sufficient engineering margin, (2) Staff field walkdowns confirmed no significant indications of deformation, distortion, or rebar corrosion, and (3) ASR was localized and occurring slowly based on existing operating experience. 25 Therefore, the Staff concluded that, although Seabrook was not conforming with its licensing basis because ASR was not accounted for in the licensing basis, its ASR-affected structures remained capable of performing their safety functions. 26 B. The 2012 Confirmatory Action Letter At an April 23, 2012 public meeting with NextEra, the Staff discussed its concerns with the long-term operability of the ASR-affected structures at Seabrook. 27 Subsequently, by letters dated May 3 and May 10, 2012, NextEra described the actions that it would take to address the degraded conditions and to ensure that Seabrook continued to meet its current licensing basis. 28 On May 16, 2012, the Staff issued a confirmatory action letter (CAL) to NextEra to confirm the licensees commitments with respect to planned actions to evaluate ASR-affected reinforced concrete structures at Seabrook. 29 These commitments included (1) submitting a root-cause analysis for the occurrence of ASR at Seabrook and related corrective action, (2) 25 Exhibit NRC001, Staff Testimony at A.10; Exhibit NRC024, Mar. 2012 Inspection Report, encl. at 5-6.

26 Id.

27 See Exhibit NRC080, Memorandum from John G. Lamb, NRC, to Meena Khanna, NRC, Forthcoming Meeting with NextEra Energy Seabrook, LLC (NextEra) Regarding Seabrook Station Concrete Degradation (Mar. 23, 2012) (ML121070659).

28 Exhibit NRC081, Letter from Paul O. Freeman, NextEra, to NRC, Seabrook Station Actions for Resolution of Alkali Silica Reaction (ASR) Issues (May 3, 2012) (ML12125A022); Exhibit NRC082, Letter from Paul O. Freeman, NextEra, to NRC, Seabrook Station Actions for Resolution of Alkali Silica Reaction (ASR) Issues (May 10, 2012) (ML12131A479).

29 Exhibit NRC001, Staff Testimony at A.10; Exhibit NRC019, CAL at 1.

revising the prompt operability determinations for some plant components, (3) completing both short-term and long-term aggregate expansion testing, and (4) establishing monitoring requirements for selected locations in areas that exhibit ASR. 30 After the issuance of the CAL, the Staff created the Seabrook ASR Issue Technical Team consisting of Staff members from various divisions across the agency; the Team coordinated the onsite inspections, in-office technical reviews, and other evaluation and assessment activities associated with NextEra's resolution of the Seabrook ASR issue. 31 In a May 24, 2012 letter responding to the CAL, NextEra submitted the results of its root-cause investigation, which concluded that the original concrete mix designs used a coarse aggregate that was susceptible to ASR. 32 This coarse aggregate used in the concrete mixes, in combination with groundwater intrusion issues for below-grade structures or other moisture sources during the life of the plant, resulted in the observed ASR in several structures at Seabrook. 33 NextEra also submitted the results of an interim structural assessment, which evaluated the structural adequacy of reinforced concrete structures at Seabrook affected by ASR and system/component anchorages in ASR-affected concrete. 34 The assessment concluded that while the reinforced concrete structures at Seabrook remained suitable for 30 Exhibit NRC019, CAL at 2-3.

31 Exhibit NRC045, Memorandum from Eric J. Leeds, NRR, and William M. Dean, Region 1, Seabrook Alkali-Silica Reaction Issue Technical Team Charter (July 9, 2012) (ML121250588).

32 Exhibit NRC078, NextEra Response to CAL, encl. 1 at 3 (unnumbered); see Exhibit INT024, SE, encl.

2 at 5; Exhibit INT010, LAR at 8 of 74 (unnumbered).

33 Id.

34 Exhibit NRC079, Interim Structural Assessment.

continued service for an interim period, additional testing was required. 35 This additional testing consisted of the proposed LSTP and the results from periodic monitoring of the affected structures at Seabrook. 36 C. Deviation from the Reactor Oversight Process and Increased Oversight In September 2012, the Staff requested approval from the NRCs Executive Director for Operations (EDO) to deviate from the reactor oversight process (ROP) to increase NRC oversight of Seabrook, partly to review NextEras compliance with the 2012 CAL (2012 Deviation Memo). 37 This increased oversight would allow the Staff to more thoroughly understand the ASR phenomenon and to confirm that ASR-affected structures at Seabrook continue to perform their safety-related function. 38 The Staff planned to use this increased oversight of Seabrook to (1) inspect NextEras completed and planned actions associated with the eleven CAL items, (2) evaluate the quality and applicability of results from the licensees proposed LSTP, (3) provide support for the development of technical guidance, and (4) continue to support communications and outreach activities for stakeholders. 39 35 Id.

36 Id. at 13.

37 Exhibit NRC083, Memorandum from William M. Dean, NRC, to R.W. Borchardt, NRC, Request for Deviation from the Reactor Oversight Process Action Matrix to Provide Increased Oversight of the Alkali-Silica Reaction Issue at Seabrook (Sept. 5, 2012) (ML12242A370) (2012 Deviation Memo).

38 Id. at 2.

39 Id.

After the EDO approved this deviation from the ROP, the Staff conducted two CAL follow-up inspections to evaluate NextEras compliance with the commitments in the CAL. 40 The first inspection in the fall of 2012 involved three weeks of onsite inspection and four months of in-office review by NRC region-based inspectors and headquarters reviewers to assess the adequacy of actions taken by NextEra to address the occurrence of ASR in reinforced concrete structures at Seabrook. 41 Additionally, for this inspection, the Staffs review was informed by a separate, independent review by Dr. Kent Harries, Associate Professor of Structural Engineering and Mechanics, University of Pittsburgh. 42 In June 2013, the Staff completed the second CAL follow-up inspection, which independently verified that NextEra had appropriately assessed and determined that all ASR-affected structures remain operable. 43 The inspection team also confirmed that NextEras root-cause evaluation was thorough and identified appropriate corrective actions. 44 During both inspections, the Staff reviewed selected procedures and records, observed ASR crack indexing measurements, conducted independent walk-through inspections to evaluate ASR-affected structures, and interviewed Seabrook 40 See Exhibit NRC084, Letter from Darrell J. Roberts, NRC, to Kevin Walsh, NextEra, Deviation from the Reactor Oversight Process Action Matrix for Seabrook Station, Unit No. 1 (Sept. 12, 2012)

(ML12258A042).

41 Exhibit NRC025, 2012 CAL Follow-up Inspection, encl. 1 at 1.

42 Exhibit NRC025, 2012 CAL Follow-Up Inspection, encl. 1 at i.

43 Exhibit NRC026, Letter from Raymond K. Lorson, NRC, to Kevin Walsh, Seabrook Station, Unit No. 1 -

Confirmatory Action Letter Follow-up Inspection - NRC Inspection Report 05000443/2012010, at 1 (Aug.

9, 2013) (ML13221A172) (2013 CAL Follow-up Inspection).

44 Id.

personnel regarding the adequacy of NextEras actions to address the impact of ASR on reinforced concrete structures. 45 On October 9, 2013, after the completion of the two CAL follow-up inspections, the Staff issued a CAL closure letter, stating that the Staff had verified that NextEra had satisfied the commitments contained in the 2012 CAL. 46 The CAL closure letter noted NextEras planned LSTP testing and NextEras continued commitment to update its operability determinations for ASR-affected structures as additional information from the testing became available. 47 The CAL closure letter also stressed that the Staff was in the process of conducting a separate review of the ASR issue as part of its review of the LAR. 48 About a month before, in a letter dated September 3, 2013, the Staff informed NextEra that the exit criteria in the 2012 Deviation Memo had been met and that inspection oversight of Seabrook would return to the ROP baseline inspection program. 49 Nonetheless, the Staff made clear that it would continue to provide focused oversight of the testing being conducted for the LSTP and NextEras continuing assessment of ASR progression in the on-site concrete structures. 50 To that end, and in connection with its continuing review of the LAR, from 45 Exhibit NRC025, 2012 CAL Follow-up Inspection, encl. 1 at 11-12; Exhibit NRC026, 2013 CAL Follow-up Inspection, encl. 1 at 13-17.

46 Exhibit NRC085, Letter from William M. Dean, NRC, Kevin Walsh, NextEra, Closure of Confirmatory Action Letter 1-12-002, Seabrook Station, Unit 1 (Oct. 9, 2013) (ML13274A670).

47 Id. at 2.

48 Id.

49 Exhibit NRC086, Letter from Darrell J. Roberts, NRC, to Kevin Walsh, NextEra, Mid-cycle Performance Review and Inspection Plan - Seabrook Station, Unit No. 1 (Report 05000443/2013006), at 1 (Sept. 3, 2013) (ML13246A107).

50 Id. at 2.

November 18-20 2013, the Staff conducted an audit of the Seabrook ASR expansion monitoring program. 51 During its audit, the Staff examined the ASR expansion monitoring program and program bases documents, interviewed NextEra representatives, and conducted walkdowns of selected ASR-affected structures. 52 The audit concluded, among other things, that the Staff needed additional information before it could determine that Seabrooks operating experience supports the sufficiency of its aging management program. 53 D. The Staff Inspections of the LSTP From late 2013 to February 2016, MPR Associates (MPR), in collaboration with the Ferguson Structural Engineering Laboratory (FSEL) at the University of Texas at Austin, conducted the LSTP, as commissioned by NextEra. 54 The LSTP included load tests to failure of large-scale specimens that reflected the characteristics of ASR-affected reinforced concrete 51 Exhibit NRC041, Letter from Richard Plasse, NRC, to Kevin Walsh, NextEra, Aging Management Program Audit Report Regarding the Seabrook Station License Renewal Application TAC No. ME4028)

(Dec. 23, 2013) (ML13354B785).

52 Id., encl. at 1.

53 Id., encl. at 8.

54 See Exhibit NRC033, May 2016 Inspection Report, encl. 2 at 1 (NextEras testing of large scale ASR-affected test specimens at FSEL commenced in late 2013 and was planned to be completed under NextEras direction by February 2016.); Exhibit INT019-R, MPR-4273, Rev. 1, Seabrook Station -

Implications of Large-Scale Test Program Results on Reinforced Concrete Affected by Alkali-Silica Reaction (July 2016) (ML18141A785) (nonproprietary) (Enclosure 5 to Letter SBK-18072) at 5-1 (PDF p.

139) (MPR-4273, LSTP Report (Rev. 1)). Although the title to INT019-R appears to indicate that the date of the exhibit is July 2016, the actual document lists March 2018 as the date. INT019-R, LSTP Report (Rev. 1) at PDF p. 98.

NextEra submitted both propriety and nonproprietary versions of MPR-4273, LSTP Report, Rev. 0, as enclosures to the Original LAR. INT010, LAR at 2; Exhibit NRC008/NRC009, MPR-4273, Rev. 0, Seabrook Station - Implications of Large-Scale Test Program Results on Reinforced Concrete Affected by Alkali-Silica Reaction (July 2016) (ML16216A242 (nonproprietary) and ML16216A246 (proprietary),

respectively) (MPR-4273 (Rev. 0)).

NextEra submitted Rev. 1 of MPR-4273 in the May 2018 MPR Reports Update. Exhibit NRC016, May 2018 MPR Reports Update at 2; INT019-R (nonproprietary); INT021 (proprietary).

structures at Seabrook and testing was completed at various levels of ASR cracking to assess its impact on selected structural limit states. 55 Specifically, the LSTP consisted of three key test program elements to evaluate the impact of ASR on (1) the performance of expansion and undercut anchors installed in concrete (the Anchor Test Program), (2) the shear capacity of reinforced concrete (the Shear Test Program), and (3) the reinforcement anchorage of rebar lap splices and flexural strength and stiffness (the Reinforcement Anchorage Test Program). 56 NextEra selected these three elements based on the 2012 interim structural assessment for Seabrook structures that identified these limit states as areas where gaps existed in available literature or available margins in Seabrook structures were low, and for which it was necessary to develop structural performance data under load to complete follow-up structural evaluations of Seabrook ASR-affected structures. 57 A fourth test program (the Instrumentation Test Program) evaluated instruments for monitoring through-thickness expansion in Seabrook reinforced concrete structures. 58 The specimens used in the LSTP experienced levels of ASR more severe than at Seabrook in order to bound the effects of potential future progression of ASR at Seabrook. 59 55 Exhibit NRC001, Staff Testimony at A.23; Exhibit INT024, SE, encl. 2 at 7-8; see Exhibit INT010, LAR at 16 of 74 (unnumbered); Exhibit INT019-R, LSTP Report, at 2-5-2-6 (PDF pp. 119-120).

56 Exhibit NRC001, Staff Testimony at A.19; Exhibit INT024, SE, encl. 2 at 7; Exhibit INT010, LAR, at 16 of 74 (unnumbered); Exhibit INT019-R at 1-2-1-3 (PDF pages 111-112).

57 Exhibit NRC001, Staff Testimony at A.19; Exhibit INT024, SE, encl. 2 at 7; Exhibit INT019-R, LSTP Report, at 1-2-1-3 (PDF pp. 111-112).

58 Exhibit NRC001, Staff Testimony at A.19; Exhibit INT024, SE, encl. 2 at 7; Exhibit INT019-R, LSTP Report, at 1-2-1-3 (PDF pp.111-112).

59 Exhibit NRC001, Staff Testimony at A.23; Exhibit INT024, SE, encl. 2 at 8; Exhibit INT010, LAR, at 17 of 74 (unnumbered); INT019-R, LSTP Report, at 2-6-1-7 (PDF pp. 120-121).

Staff oversight of the LSTP and NextEras monitoring of ASR during this period (late 2013 to February 2016) involved direct inspection by NRC regional inspectors and headquarters structural experts to ensure that the results were being appropriately reflected in the operability assessments and evaluations of ASR-affected structures. 60 Staff inspections of the LSTP observed, on a sampling basis, the setup of the program and the facilities, fabrication and concrete pour, and testing of the specimens. 61 During the inspections, the NRC inspectors did not identify any findings related to the LSTP and determined that the licensee implemented appropriate quality assurance program requirements. 62 60 Exhibit NRC001, Staff Testimony at A.10; see Exhibit NRC026, 2013 CAL Follow-up Inspection, encl.

at 1; Exhibit NRC027, Letter from Glenn T. Dentel, NRC, to Kevin Walsh, NextEra, Seabrook Station, Unit No. 1 - NRC Integrated Inspection Report 05000443/2013005 (Jan. 30, 2014) (ML14030A509) (Jan.

2014 Inspection Report); Exhibit NRC028, Letter from Glenn T. Dentel, NRC, to Kevin Walsh, NextEra, Seabrook Station, Unit No. 1 - NRC Integrated Inspection Report 05000443/2014002 (May 6, 2014)

(ML14127A376) (May 2014 Inspection Report); Exhibit NRC030, Letter from Glenn T. Dentel, NRC, to Dean Curtland, NextEra, Seabrook Station, Unit No. 1 - NRC Integrated Inspection Report 05000443/2014005 (Feb. 6, 2015) (ML15037A172) (Feb. 2015 Inspection Report); Exhibit NRC032, Letter from Fred L. Bower, III, NRC, to Dean Curtland, NextEra, Seabrook Station, Unit No. 1 - NRC Integrated Inspection Report 05000443/2015004 and Independent Spent Fuel Storage Installation Report No. 07200063/2015001 (Feb. 12, 2016) (ML16043A391) (Feb. 2016 Inspection Report).

61 Exhibit NRC001, Staff Testimony at A.10; Exhibit INT024, SE, encl. 2 at 10; see, e.g., Exhibit NRC026, 2013 CAL Follow-up Inspection, encl. at 1, 9; Exhibit NRC027, Jan. 2014 Inspection Report, encl. at 17-19; Exhibit NRC028, May 2014 Inspection Report, encl. at 19-22; Exhibit NRC030, Feb. 2015 Inspection Report, encl. at 23; Exhibit NRC032, Feb. 2016 Inspection Report, encl. at 25-28.

62 Exhibit NRC001, Staff Testimony at A.10; Exhibit INT024, SE, encl. 2 at 10; see, e.g., Exhibit NRC026, 2013 CAL Follow-up Inspection, encl. at 1, 9; Exhibit NRC027, Jan. 2014 Inspection Report, encl. at 17-19; Exhibit NRC028, May 2014 Inspection Report, encl. at 19-22; Exhibit NRC030, Feb. 2015 Inspection Report, encl. at 23 (discussing audit conducted at FSEL during the week of October 26, 2015); Exhibit NRC017, Letter from Tam Tran, NRC, to Dean Curtland, NextEra, Alkali Silica Reaction Monitoring Aging Management Program Audit Report Regarding the Seabrook Station, Unit 1, License Renewal (TAC No.

ME4028) (Dec. 17, 2015) (ML15307A022); Exhibit NRC018, Seabrook ASR-Monitoring Program Audit Report, Enclosure to Dec. 17, 2015 Letter to NextEra (undated) (ML15337A047) (containing results of Staffs audit at FSEL during the week of October 26, 2015) (Dec. 2017 Site Audit Report); Exhibit NRC032, Feb. 2016 Inspection Report, encl. at 25-28.

E. The Staff Inspections of the Implementation of the ASR Expansion Monitoring Program at Seabrook With respect to the monitoring of ASR at Seabrook, from 2014 to 2015, NRC inspectors documented findings of very low safety significance associated with discrete, large horizontal cracks in an internal wall of the residual heat removal vaults, 63 cracks in the fuel storage building, 64 and seismic and fire seals in the containment enclosure building that appeared to have been degraded due to differential movement between adjoining concrete buildings. 65 In addition, on May 6, 2016, the Staff documented a finding and associated notice of violation related to NextEras maintenance of its prompt operability determinations for ASR-related structures. 66 The Staff concluded that all of these findings were of very low safety significance because the safety function of these structures was not affected. 67 On August 9, 2016, after the completion of the LSTP in February 2016, NextEra submitted its updated license renewal application, which included updates to the aging 63 Exhibit NRC001, Staff Testimony at A.10; Exhibit NRC029, Letter from Glenn T. Dentel, NRC, to Dean Curtland, NextEra, Seabrook Station, Unit No. 1 - NRC Integrated Inspection Report 05000443/2014003, encl. at 3, 15-16, (Aug. 5, 2014) (ML14212A458) (Aug. 2014 Inspection Report);

see Exhibit NRC033, May 2016 Inspection Report at 1, encl. 1 at 1-2.

64 Exhibit NRC030, Feb. 2015 Inspection Report, encl. at 3, 8-10.

65 Exhibit NRC001, Staff Testimony at A.10; Exhibit NRC031, Letter from Glenn T. Dentel, NRC, to Dean Curtland, NextEra, Seabrook Station, Unit No. 1 - NRC Integrated Inspection Report 05000443/2015002, encl. at 3, 18-23 (Aug. 5, 2015) (ML15217A256) (Aug. 2015 Inspection Report); see Exhibit NRC033, May 2016 Inspection Report at 1, encl. 1 at 1-2.

66 Exhibit NRC033, May 2016 Inspection Report at 2, encl. 1 at 1-2; encl. 2 at 1.

67 Id., encl. 2 at 1; Exhibit NRC029, Aug. 2014 Inspection Report, encl. at 3, 15-16; Exhibit NRC030, Feb.

2015 Inspection Report, encl. at 3, 8-10; Exhibit NRC031, Aug. 2015 Inspection Report, encl. at 3; Exhibit NRC033, May 2016 Inspection Report at 1, encl. 1 at 1-2; see Exhibit NRC001, Staff Testimony at A.10.

management programs based on the results the LSTP. 68 Thereafter, the Staff conducted several inspections to review the adequacy of NextEras monitoring of ASR-affected structures. 69 During these inspections, the Staff performed independent walkdowns of ASR-affected areas, examined crack gauges and the placement of extensometers, and reviewed reports of recently collected measurement data, including in-plane and through-thickness expansion, to verify that the structures were well within the established acceptable monitoring parameters. 70 The Staff also conducted three onsite audits after the license renewal application 68 Letter from Eric McCartney, NextEra, to NRC Document Control Desk, Seabrook Station, License Renewal Application Relating to the Alkali-Silica Reaction (ASR) Monitoring Program (Aug. 9, 2016)

(ML16224B079).

69 Exhibit NRC035, Letter from Fred L. Bower, III, NRC, to Eric McCartney, NextEra, Seabrook Station, Unit No. 1 - Integrated Inspection Report 05000443/2016004, encl. at 17-18 (Feb. 8, 2017)

(ML17040A220) (Feb. 2017 Inspection Report); Exhibit NRC036, Letter from Fred L. Bower, III, NRC, to Mano Nazar, NextEra, Seabrook Station, Unit No. 1 - Integrated Inspection Report 05000443/2017002, encl. at 31-32 (Aug. 14, 2017) (ML17227A018) (Aug. 2017 Inspection Report); Exhibit NRC037, Letter from Fred L. Bower, III, NRC, to Mano Nazar, NextEra, Seabrook Station, Unit No. 1 - Integrated Inspection Report 05000443/2017004, encl. at 24-27 (Feb. 12, 2018) (ML18043A821) (Feb. 2018 Inspection Report); Exhibit NRC038, Letter from Fred L. Bower, III, NRC, to Mano Nazar, NextEra, Seabrook Station, Unit No. 1 - Integrated Inspection Report 05000443/2018001, encl. at 8-9 (May 14, 2018) (ML18134A222) (May 2018 Inspection Report); Exhibit NRC039, Letter from Mel Gray, III, NRC, to Mano Nazar, NextEra, Seabrook Station, Unit No. 1 - Integrated Inspection Report 05000443/2018011, encl. at 7-9 (Aug. 10, 2018) (ML18222A292) (Aug. 2018 Inspection Report); Exhibit NRC040, Letter from Fred L. Bower, NRC, to Mano Nazar, NextEra, Seabrook Station, Unit No. 1 - Integrated Inspection Report 05000443/2018003 (Nov. 13, 2018) (ML18318A009) (Nov. 2018 Inspection Report).

Between the end of the LSTP in February 2016 and NextEras August 9, 2016 update to the license renewal application, the Staff completed an additional inspection, which included a review of operability determinations related to ASR-affected structures. Exhibit NRC034, Letter from Fred L. Bower, NRC, to Eric McCartney, NextEra, Seabrook Station, Unit No. 1 - Integrated Inspection Report 05000443/2016002, encl. at 18-20 (Aug. 5, 2016) (ML16218A455).

70 Exhibit NRC035, Feb. 2017 Inspection Report, encl. at 17-18; Exhibit NRC036, Aug. 2017 Inspection Report, encl. at 31-32; Exhibit NRC037, Feb. 2018 Inspection Report, encl. at 24-27; Exhibit NRC038, May 2018 Inspection Report, encl. at 8-9; Exhibit NRC040, Nov. 2018 Inspection Report, encl. at 9-10.

update, as documented in reports dated December 21, 2016, 71 July 26, 2017, 72 and May 21, 2018. 73 During all three onsite audits, the Staff specifically reviewed the calculations and other supporting documentation implementing the ASR expansion monitoring program proposed in the LAR. 74 Additionally, the latter two site visits were conducted as part of a larger regulatory audit of the LAR. 75 On September 28, 2019, the Staff issued its final Safety Evaluation Report (SER) for the Seabrook license renewal application, documenting the results of the Staffs safety review and 71 Exhibit NRC042, Letter from Tam Tran, NRC, to Eric McCartney, NextEra, Alkali Silica Reaction Monitoring Aging Management Program Audit Report Regarding the Seabrook Station, Unit 1, License Renewal (CAC No. ME4028) (Dec. 21, 2016) (ML16333A247).

72 Exhibit NRC043, Letter from Justin C. Pool, NRC, to Mano Nazar, NextEra, Seabrook Station, Unit No.

1 - Site Visit Report Regarding Regulatory Audit for License Amendment Request Re: Alkali-Silica Reaction License Amendment Request and License Renewal Alkali-Silica Reaction Aging Management Program Review (CAC No. MF8260; EPID L-2016-LLA-0007), at 1, encl. at 2 (July 26, 2017)

(ML17199T383) (July 2017 Site Audit Report) (stating that the Staff conducted the site visit from June 5, 2017 to June 9, 2017).

73 Exhibit NRC044, Letter from Justin C. Pool, NRC, to Mano Nazar, NextEra, Seabrook Station, Unit No.

1 - Site Visit Report Regarding Regulatory Audit for License Amendment Request Re: Alkali-Silica Reaction License Amendment Request and License Renewal Alkali-Silica Reaction Aging Management Program Review (CAC No. MF8260; EPID L-2016-LLA-0007), at 1, encl. at 2 (May 21, 2018)

(ML18135A046) (May 2018 Site Audit Report) (stating that the Staff conducted the site visit from March 19, 2018 to March 22, 2018).

74 Exhibit NRC018, Dec. 2017 Site Audit Report, encl. 1 at 1-3; Exhibit NRC043, July 2017 Site Audit Report at 1; Exhibit NRC044, May 2018 Site Audit Report at 1.

75 Exhibit INT024, SE, encl. 2 at 33, 35, 39, 40-42, 56, 60-61; Exhibit NRC087, Email from Justin Poole, NRC, to Kenneth Browne, NextEra, Audit Plan Regarding Seabrook ASR License Amendment Review (Jan. 13, 2017) (ML17017A162); Exhibit NRC043, July 2017 Site Audit Report at 1; Exhibit NRC044, May 2018 Site Audit Report at 1.

closing the open item related to ASR. 76 On March 12, 2019, the Staff issued the renewed license for Seabrook. 77 II. The ASR License Amendment Request NextEra submitted the LAR related to ASR at Seabrook in August 2016 and supplemented it in September 2016, October 2017, December 2017, and June 2018. 78 NextEra supplemented its application in response to Staff questions as well as a public meeting with the Staff on August 24, 2017 79 and two site audits. 80 The LAR contained various reports on ASR at Seabrook, including (1) MPR-4288, Seabrook Station: Impact of Alkali-Silica Reaction on Structural Design Evaluations, which includes NextEras methodology for performing evaluations of structural adequacy on ASR-affected reinforced concrete structures at Seabrook (MPR-4288, Structure Deformation Report), 81 (2) MPR-4273, Seabrook Station - Implications of Large-Scale Test Program Results on Reinforced Concrete Affected by Alkali-Silica Reaction, 76 Safety Evaluation Report Related to the License Renewal of Seabrook Station, Docket No. 50-443, NextEra Energy Seabrook, LLC at 1-9 (Sept. 28, 2018) (ML18362A370) (LRA SER).

77 See NextEra Energy Seabrook, LLC; Seabrook Station, Unit No. 1, License Renewal and Record of Decision; Issuance, 84 Fed. Reg. 9563, 9563 (March 15, 2019).

78 INT010, LAR at 1 (unnumbered); Exhibit NRC010, Sept. 2016 LAR Supplement; Exhibit NRC013, Oct.

2017 LAR Supplement; Exhibit NRC014, Dec. 2017 LAR Supplement; Exhibit NRC015, June 2018 LAR Supplement.

79 Exhibit NRC046, Summary of August 24, 2017, Meeting with NextEra Energy Regarding License Amendment Request on Alkali Silica Reaction (Oct. 13, 2017) (ML17278A748).

80 Exhibit NRC043, July 2017 Site Audit at 1; Exhibit NRC044, May 2018 Site Audit at 1.

81 Exhibit INT012, MPR-4288, Rev. 0, Seabrook Station: Impact of Alkali-Silica Reaction on Structural Design Evaluations (July 2016) (Enclosure 2 to Letter SBK-L-16071 [Original LAR]) (nonproprietary)

(MPR-4288, Structure Deformation Report (Rev. 0)); Exhibit INT014, MPR-4288, Rev. 0, Seabrook Station: Impact of Alkali-Silica Reaction on Structural Design Evaluations (July 2016) (Enclosure 2 to Letter SBK-L-16071 [Original LAR]) (proprietary). Although the title of INT014 states that it is Enclosure 2 to Letter SBK-L-16071, the Original LAR, the proprietary version of MPR-4288, Rev. 0 is enclosure 5 to the Original LAR; enclosure 2 is the nonproprietary version of MPR-4288, Rev. 0. INT010, LAR at 2.

which includes a detailed discussion of the LSTP (MPR-4273, LSTP Report), 82 (3) MPR-4153, Seabrook Station - Approach for Determining Through-Thickness Expansion from Alkali-Silica Reaction, which describes the licensees methodology for its ASR expansion monitoring program (MRP-4153, ASR Monitoring Report), 83 and (4) Simpson Gumpertz & Heger, Inc.

Report, Development of ASR Load Factors for Seismic Category I Structures (including Containment) at Seabrook Station, which details the licensees methodology for evaluating ASR related loads on concrete structures at Seabrook (ASR Loads Report). 84 The LAR was necessary to address ASR at Seabrook because the design codes for the affected structures do not account for the impacts of ASR. 85 Specifically, at Seabrook, safety-related structures other than the containment were designed and constructed to comply with the 82 INT019-R, MPR-4273, LSTP Report (Rev. 1) (nonproprietary); INT021, MPR-4273, LSTP Report (Rev.

1) (proprietary); Exhibit NRC008, MPR-4273, LSTP Report, Rev. 0 (nonproprietary); Exhibit NRC009, MPR-4273, LSTP Report (Rev. 0) (proprietary).

83 INT018-R, MPR-4153, Rev. 3, Seabrook Station-Approach for Determining Through-Thickness Expansion from Alkali-Silica Reaction (Sept. 2017) (nonproprietary version) (Enclosure 4 to Letter SBK-18072) (ML16279A050) (MPR-4253, ASR Monitoring Report (Rev. 3)); INT020, MPR-4153, Rev. 3, Seabrook Station-Approach for Determining Through-Thickness Expansion from Alkali-Silica Reaction (Sept. 2017) (Proprietary version) (Enclosure 6 to Letter SBK-18072); Exhibit NRC011, Enclosure 3 to Sept. 2016 LAR Supplement, MPR-4153, Rev. 2, Seabrook Station-Approach for Determining Through-Thickness Expansion from Alkali-Silica Reaction" (July 2016) (nonproprietary) (MPR-4153, ASR Monitoring Report (Rev. 2)) (ML16279A050); Exhibit NRC012, Enclosure 5 to Sept. 2016 LAR Supplement, Rev. 2, Seabrook Station - Approach for Determining Through Thickness Expansion from Alkali-Silica Reaction (July 2016) (proprietary).

84 Exhibit INT013, SG&H Report 160268-R-01, Rev. 0, Development of ASR Load Factors for Seismic Category I Structures (Including Containment) at Seabrook Station, Seabrook, NH (July 2016) (Enclosure 4 to Letter SBK-L-16071 [Original LAR]) (ML16216A243).

85 Exhibit NRC001, Staff Testimony at A.12; Exhibit INT010, LAR, at 8-9, 11 (unnumbered). At Seabrook, safety-related structures other than the containment were designed and constructed to comply with the 1971 edition of American Concrete Institute (ACI) Standard 318, Building Code Requirements for Reinforced Concrete (ACI 318-71). Exhibit INT010, LAR, at 8-9, 11. The containment was designed and constructed to comply with the 1975 edition of the American Society of Mechanical Engineers (ASME)

Boiler and Pressure Vessel Code Section III, Division 2, Subsection CC. Id. Neither of these codes, however, include methods to analyze and address the effects of ASR on structural properties. Id.

1971 edition of American Concrete Institute (ACI) Standard 318, Building Code Requirements for Reinforced Concrete (ACI 318-71). 86 The containment was designed and constructed to comply with the 1975 edition of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code Section III, Division 2, Subsection CC. 87 Neither of these codes, however, include methods to analyze and address the effects of ASR on structural properties.

Therefore, the proposed methodology changes and supporting technical bases were necessary to account for ASR in the design basis of the containment and other seismic Category I reinforced concrete structures that are affected by ASR. 88 ASR can affect a concrete structure in two primary ways. First, cracking from ASR can affect structural capacity, that is, the load carrying capacity for critical limit states. 89 Second, cracking from ASR can affect the demand on a structure by introducing a new load. 90 The LAR proposed to address (1) the effect of ASR on structural capacity through an ASR expansion monitoring program 91 and (2) the effect of ASR on the demand on a structure through a structure deformation monitoring program. 92 86 Exhibit INT010, LAR, at 8-9, 11 (unnumbered).

87 Id.

88 Exhibit NRC001, Staff Testimony at A.12; Exhibit INT024, SE encl. 2 at 5-6; Exhibit INT010, LAR, at 9-10 (unnumbered).

89 Exhibit NRC001, Staff Testimony at A.13; Exhibit INT010, LAR at 9-10 (unnumbered).

90 Id.

91 Exhibit NRC001, Staff Testimony at A.14; Exhibit INT010, LAR at 9-10, 31-33. (unnumbered).

92 Exhibit NRC001, Staff Testimony at A.14; Exhibit INT010, LAR at 9-10, 33-34 (unnumbered).

A. The ASR Expansion Monitoring Program The ASR expansion monitoring program measures cracks in ASR-affected concrete, first in the in-plane direction using the crack indexing (CI) or combined crack indexing (CCI) 93 method. 94 Then, when in-plane expansion reaches a specified threshold, it measures cracks in the through-thickness direction using the readings taken from a snap-ring borehole extensometer (SRBE) combined with a calculation of the through-thickness expansion that had occurred up to the time of the SRBEs installation. 95 The purpose of this monitoring is to ensure that the in-plane, through-thickness, and volumetric 96 expansions remain below the ASR expansion limits for the structural limit states of shear, flexure, reinforcement anchorage, and anchors, which are based on the expansion observed during the LSTP. 97 The interval for this monitoring is based on the amount of in-plane expansion, categorized into three tiers: (Tier 1) when there is no indication of pattern cracking or water ingress, the inspection frequency is as prescribed in the Seabrook routine structural monitoring program; (Tier 2) when there are areas with pattern cracking that cannot be accurately measured or in-plane expansion of 0.05%, the 93 The CCI is the weighted average of the Cl in the two measured in-plane directions. INT024, SE, encl. 2 at 34.

94 Exhibit NRC001, Staff Testimony at A.15; Exhibit INT010, LAR, at 17 (unnumbered); Exhibit INT024, SE, encl. 2 at 9.

95 Exhibit NRC001, Staff Testimony at A.15; Exhibit INT010, LAR, at 17 (unnumbered); Exhibit INT024, SE, encl. 2 at 21; see INT019-R, LSTP Report, at 5-17-5-18.

96 Volumetric expansion is the combination of in-plane and through-thickness expansions. Exhibit NRC001, Staff Testimony at A.15.

97 Exhibit INT010, LAR, at 30-33 (unnumbered).

inspection frequency is 30 months; and (Tier 3) when there is in-plane expansion of 0.1%, the inspection frequency is 6 months. 98 B. The Structure Deformation Monitoring Program As described above, in 2015, NRC inspectors documented seismic and fire seals in the containment enclosure building that appeared to have been degraded due to differential movement between adjoining concrete buildings. 99 Both NextEra and the Staff determined that this finding was the result of an effect of ASR that is separate from the expansion effect of ASR that had been addressed in the LSTP. 100 Specifically, structural demand can be added to a structure by an internal self-straining ASR load due to restraint to ASR expansion from reinforcement, geometry, and boundary conditions causing deformation. 101 Because the LSTP did not address this effect of ASR, NextEra developed an additional monitoring program, called the structure deformation monitoring program, 102 to manage building deformation and included it as part of the LAR along with the ASR expansion monitoring program. 103 98 Exhibit INT010, LAR, at 33, tbl. 5 (unnumbered).

99 Exhibit NRC031, Aug. 2015 Inspection Report, encl. at 3, 18-23; see Exhibit NRC033, May 2016 Inspection Report at 1, encl. 1 at 1-2.

100 Exhibit INT024, SE, encl. 2 at 32 ([I]n addition to an internal prestressing effect, ASR expansion can lead to building deformation that, when restrained, results in load and additional stresses on affected structures.).

101 Exhibit NRC001, Staff Testimony at 8.

102 The final safety evaluation report for the Seabrook license renewal application refers to this program as the Building Deformation Monitoring Program. LRA SER at 1-8.

103 See Exhibit INT010, LAR, at 24, 30, 33-34 of 74 (unnumbered).

The structure deformation monitoring program involves a three-stage process to evaluate seismic Category I structures. 104 First, in Stage 1, NextEra screens each seismic Category I structure for susceptibility to structural deformation caused by ASR and susceptible structures. 105 In Stage 2, NextEra performs an analytical evaluation on structures that the Stage One Screening Evaluation identifies as susceptible to deformation but do not satisfy ACI 318-71 acceptance criteria. 106 In Stage 3, NextEra performs a detailed design confirmation calculation when the Stage Two Analytical Evaluation concludes that some area of a structure does not satisfy ACI 318-71 acceptance criteria or when the structure has sufficient deformation that may impact demands computed in the original design. 107 Both Stage 2 and Stage 3 involve the use of finite element models. 108 Each analysis stage establishes threshold monitoring limits for each structure and the structures are then monitored to ensure that the threshold monitoring limits are not exceeded. 109 Structures classified as Stage 1 are monitored every 3 years, structures classified as Stage 2 are monitored every 18 months, and structures classified as Stage 3 are monitored every 6 months. 110 The structure deformation monitoring 104 Id. at 24.

105 Id.

106 Id. at 25.

107 Id.

108 Id. at 25, 33-34.

109 Id.

110 Id.

categories (i.e., Stages 1, 2, and 3) are distinct from the ASR expansion monitoring categories (i.e., Tiers 1, 2, and 3). 111 III. C-10s Challenge to the ASR License Amendment Request On February 7, 2017, the NRC published a notice of opportunity to request a hearing on the LAR. 112 On April 10, 2017, C-10 filed a petition for leave to intervene, requesting a hearing on the LAR with respect to ten proposed contentions. 113 On May 5, 2017, the Staff and NextEra filed answers opposing the granting of the requested hearing due to C-10s failure to establish standing in its Petition. 114 NextEra also argued that C-10 had not pled an admissible contention, while the Staff determined that C-10s proposed contentions could be understood and reformulated as a single, admissible contention. 115 In LBP-17-07, the Board ruled that C-10 had standing to intervene and had pled five admissible contentions, which the Board reformulated into a single contention:

The large-scale test program, undertaken for NextEra at the FSEL, has yielded data that are not representative of the progression of ASR at Seabrook. As a result, the proposed monitoring, acceptance criteria, and inspection intervals are not adequate. 116 111 Id. at 34, tbl. 6.

112 Applications and Amendments to Facility Operating Licenses and Combined Licenses Involving Proposed No Significant Hazards Considerations and Containing Sensitive Unclassified Non-Safeguards Information and Order Imposing Procedures for Access to Sensitive Unclassified Non-Safeguards Information, 82 Fed. Reg. 9,601, 9,604 (Feb. 7, 2017).

113 C-10 Research and Education Foundation, Inc. Petition for leave to intervene: Nuclear Regulatory Commission Docket No. 50-443 (Apr. 10, 2017) (Petition).

114 NRC Staffs Answer to C-10 Research and Education Foundation, Inc. Petition for Leave to Intervene (May 5, 2017) (Staffs Ans. to Petition); NextEras Answer Opposing C-10 Research & Education Foundations Petition for Leave to Intervene and Hearing Request on NextEra Energy Seabrook, LLCs License Amendment Request 16-03 (May 5, 2017) (NextEras Ans. to Petition).

115 NextEras Ans. to Petition at 16; Staffs Ans. to Petition at 26.

116 NextEra Energy Seabrook, LLC (Seabrook Station, Unit 1), LBP-17-7, 86 NRC 59, 68, 90 (2017). The Board concluded that C-10s other contentions were inadmissible. Id. at 131-37.

An evidentiary hearing on the admitted contention is scheduled for September 24-27, 2019 in Newburyport, Massachusetts. 117 IV. The Staffs Safety Evaluation of the ASR License Amendment Request The Staff completed a draft safety evaluation (SE) for the LAR on September 28, 2018, which it provided to the Advisory Committee on Reactor Safeguards (ACRS). 118 Ultimately, on March 11, 2019, the Staff completed a final SE. 119 In the final SE, the Staff found that the licensee developed a representative test program and that it is reasonable to apply the conclusions of the MPR/FSEL LSTP to the structures at Seabrook within the bounds and limits of the test program, regardless of the results of material property testing on ASR-affected concrete cores. 120 In addition, recognizing that NextEras proposed ASR expansion monitoring program was a first-of-a-kind approach, the Staff included a license condition that requires NextEra to perform the following actions to confirm the continued applicability of the LSTP to ASR-affected structures at Seabrook:

a. Conduct assessments of expansion behavior using the approach provided in Appendix B of [MPR-4273, LSTP Report], to confirm that future expansion behavior of ASR affected structures at Seabrook Station is comparable to what was observed in the [LSTP] and to check margin for future expansion. Seabrook completed the first expansion assessment in March 2018; and will complete subsequent expansion assessments every ten years thereafter.

117 Licensing Board Notice of Hearing (Notice of Evidentiary Hearing and Opportunity to Provide Oral and Written Limited Appearance Statements) at 3 (June 25, 2019) (unpublished).

118 Exhibit NRC047, Memorandum from James G. Danna, NRC, to Andrea D. Veil, ACRS, Seabrook Station, Unit No. 1 - Submission of Alkali-Silica Reaction License Amendment Request Draft Safety Evaluation to Support the Advisory Committee on Reactor Safeguards Review of Seabrook License Renewal (Sept. 28, 2018) (ML18226A205).

119 Exhibit INT024 at 1.

120 Exhibit INT024, SE, encl. 2 at 31.

b. Corroborate the concrete modulus-expansion correlation used to calculate pre-instrument through-thickness expansion, as discussed in [MPR-4153 ASR Monitoring Report]. The corroboration will cover at least 20 percent of extensometer locations on ASR-affected structures and will use the approach provided in Appendix C of [MPR-4273, LSTP Report]. Seabrook will complete the initial study no later than 2025 and a follow-up study 10 years thereafter. 121 The same day the Staff issued the final SE, March 11, 2019, the Staff issued a final no significant hazard consideration determination and issued the requested license amendment, as conditioned. 122 V. The Independent Review of the LSTP by RES As part of its review of the LAR, the Office of Nuclear Reactor Regulation (NRR) requested an independent review on the overall adequacy of the LSTP by the Office of Nuclear Regulatory Research (RES), which assigned the task to Jacob Philip. 123 Mr. Philip reviewed MPR-4153, Revision 2, 124 MPR-4273, Revision 0, 125 and MPR-4288, Revision 0, 126 concurred with NextEras LSTP approach in general, and recommended that NextEra corroborate the normalized elastic modulus-expansion curve derived from the LSTP on structures at Seabrook (which the Staff subsequently required as part of its license condition). 127 In addition, after 121 Id., encl. 2 at 59-60.

122 84 Fed. Reg. at 9564.

123 Exhibit NRC005, Jacob Philip Testimony at A.3; Exhibit INT024, SE, encl. 2 at 30-31.

124 Exhibits NRC011/NRC012, MPR-5153, ASR Monitoring Report (Rev. 2) (nonproprietary and proprietary, respectively).

125 Exhibit NRC008, MPR-4273 (Rev. 0) (nonproprietary); Exhibit NRC009, MPR-4273 (Rev. 0)

(proprietary).

126 INT012, MPR-4288, Structure Deformation Report (Rev. 0) (nonproprietary); Exhibit INT014, MPR-4288, Rev. 0, Seabrook Station: Impact of Alkali-Silica Reaction on Structural Design Evaluations (July 2016) (Enclosure 2 to Letter SBK-L-16071 [Original LAR]) (proprietary).

127 Exhibit NRC005, Jacob Philip Testimony at A.6, A.8, A.9; Exhibit INT024, SE, encl. 2 at 30-31.

reviewing MPR-4273, which describes in detail the LSTP, Mr. Philip concluded that the LSTP with the use of large specimens is appropriate, greatly minimizes uncertainties associated with scaling, and enables the licensee to apply the test results to the analysis of the ASR condition existing at Seabrook. 128 In particular, Mr. Philip noted that the sizes of the specimens used in the LSTP were of the same order as those at Seabrook and equipped with similar reinforcement. 129 The Staff incorporated Mr. Philips conclusions into the SE. 130 VI. The Independent Review of ASR at Seabrook by the ACRS The ACRS also conducted an independent review of NextEras program for addressing ASR at Seabrook as part of its review of the license renewal application for Seabrook. The ACRS is independent of the Staff and reports directly to the Commission, which appoints its members. 131 In a letter to the Chairman dated December 14, 2018, the ACRS concluded that the LAR establishes a robust analytical methodology, supported by a comprehensive large scale test program, for the treatment and monitoring of [ASR]-affected Seismic Category I structures at Seabrook. 132 With respect to the license renewal application, the ACRS agreed with the Staff that NextEras aging management programs to monitor ASR and incorporate the ASR methodology described in the LAR, assure that the effects of [ASR] will be effectively tracked 128 Exhibit INT024, SE, encl. 2 at 30; see Exhibit NRC005, Jacob Philip Testimony at A.10.

129 Id.

130 Exhibit INT024, SE, encl. 2 at 30.

131 Atomic Energy Act of 1954, as amended, § 29, Advisory Committee on Reactor Safeguards; composition; tenure; duties; compensation (42 U.S.C. § 2039) (Nov. 10, 1998).

132 Letter from Michael Corradini, Chairman, ACRS, to Kristine L. Svinicki, Chairman, NRC, Seabrook Station Unit 1 License Renewal Application: Review of Licensee Program Addressing Alkali-Silica Reaction, at 1 (Dec. 14, 2018) (ML18348A951) (Corradini Letter).

and evaluated through the end of the license renewal application period of extended operation. 133 The ACRS also independently reviewed the Staffs safety evaluations for both the license renewal application and the LAR and agreed with the Staffs conclusions, noting that the Staffs safety evaluations provide thorough assessments and findings. 134 With respect to the LSTP specifically, the ACRS found that [t]he LSTP test samples were highly representative of the ASR-affected structures at Seabrook. 135 The ACRS noted that, although there were limited data available on the effects of ASR on highly constrained structures at the time of the discovery of ASR at Seabrook, since then a large body of ASR research similar to the LSTP is ongoing and that this research has produced similar results to the LSTP and has chosen a similar approach of fabricating prototypical, structural-sized test samples, with concrete produced to artificially accelerate ASR. 136 The ACRS described the Staffs review of the LAR and LSTP as deliberate and comprehensive. 137 DISCUSSION I. Legal Standards Under 10 C.F.R. § 50.90, whenever a holder of a license wishes to amend the license, including technical specifications in the license, an application for amendment must be filed, fully describing the changes desired. Under 10 C.F.R. § 50.92(a), the NRC is guided by the considerations that govern the issuance of initial operating licenses, to the extent applicable and 133 Id.

134 Id. at 2.

135 Id. at 3 (emphasis added).

136 Id. at 4.

137 Id.

appropriate, in determining whether an amendment to an operating license will be issued to the applicant. In turn, both the common standards for construction permits and operating licenses in 10 C.F.R. § 50.40(a), and those specifically for issuance of operating licenses in 10 C.F.R.

§ 50.57(a)(3), provide that there must be reasonable assurance that the activities at issue will comply with regulations and can be conducted without endangering the health and safety of the public. As the Commission has stated, [a] license amendment request must provide sufficient documentation and analysis to show that the licensee has complied with the relevant requirements, thereby demonstrating that the amended license will continue to provide reasonable assurance of adequate protection of public health and safety. 138 Seabrook Updated Final Safety Analysis Report (UFSAR) Section 3.1, Conformance to NRC General Design Criteria, discusses the extent to which the design criteria for plant structures, systems, and components important to safety meet the NRC General Design Criteria for Nuclear Power Plants, specified in 10 C.F.R. Part 50, Appendix A (GDC). 139 For each design criterion, the UFSAR discusses how Seabrooks principal design features meet the criterion, and the UFSAR identifies any exceptions that are taken. 140 The GDC that are applicable to the UFSAR changes proposed in the LAR are GDC 1 (Quality Standards and Records), 141 2 (Design Bases for Protection Against Natural 138 Entergy Nuclear Operations, Inc. (Palisades Nuclear Plant), CLI-15-22, 82 NRC 310, 316 (2015).

139 Exhibit NRC007, Seabrook Station Updated Final Safety Analysis Report, Chapter 3, Design of Structures, Components, Equipment and Systems, Revision 18, § 3.1 (October 2017) (ML17310A406)

(UFSAR); see 10 C.F.R. Part 50, App. A.

140 Exhibit NRC007, UFSAR § 3.1.

141 Id. § 3.1.1.1 at 1-2; see Exhibit INT024, SE, encl. 2 at 2; Exhibit INT010, LAR at 35 of 74 (unnumbered).

Phenomena), 142 4 (Environmental and Missile Design Bases), 143 16 (Containment Design), 144 and 50 (Containment Design Basis). 145 Of these, GDC 1, 2, and 4 apply to all Seabrook seismic Category I structures, including containment; GDC 16 and 50 apply only to containment. 146 In addition, Appendix B to 10 C.F.R. Part 50 establishes quality assurance requirements for the design, manufacture, construction, and operation of structures, systems, and components that prevent or mitigate the consequences of postulated accidents that could cause undue risk to the health and safety of the public. 147 Activities related to the changes proposed in the LAR include procurement control measures on purchased materials, equipment, services, and design control measures. 148 Section Ill, Design Control, of Appendix B to 10 C.F.R. Part 50, requires that the design control measures be established to ensure that applicable regulatory requirements and the design basis are correctly translated into specifications, drawings, procedures, and instructions. 149 These measures must include provisions to ensure that appropriate quality standards are specified and included in design documents and that 142 Exhibit NRC007, UFSAR § 3.1.1.2 at 2-3; see Exhibit INT024, SE, encl. 2 at 2; Exhibit INT010, LAR at 35 of 74 (unnumbered).

143 Exhibit NRC007, UFSAR § 3.1.1.4 at 3-4; see Exhibit INT024, SE, encl. 2 at 2; Exhibit INT010, LAR at 35 of 74 (unnumbered).

144 Exhibit NRC007, UFSAR § 3.1.2.7 at 8-9; see Exhibit INT024, SE, encl. 2 at 2; Exhibit INT010, LAR at 35 of 74 (unnumbered).

145 Exhibit NRC007, UFSAR § 3.1.5.1 at 29-30; see Exhibit INT024, SE, encl. 2 at 2; Exhibit INT010, LAR at 35 of 74 (unnumbered).

146 Exhibit INT024, SE, encl. 2 at 2.

147 10 C.F.R. Part 50, Appendix B.

148 Exhibit INT024, SE, encl. 2 at 5.

149 10 C.F.R. Part 50, Appendix B § III.

deviations from such standards are controlled. 150 Design changes, including field changes, must be subject to design control measures commensurate with those applied to the original design. 151 In this proceeding, NextEra carries the burden of proof on the issue of whether there is reasonable assurance that operation in the manner proposed by the LAR, as conditioned, will not endanger the health and safety of the public. 152 The Commission has cautioned that

[r]easonable assurance is not quantified as equivalent to a 95% (or any other percent) confidence level, but is based on sound technical judgment of the particulars of a case and on compliance with our regulations. 153 To satisfy this reasonable assurance standard, NextEra must make a showing that meets the preponderance of the evidence threshold of compliance with the applicable regulations. 154 As indicated above, the applicable regulations in this proceeding are GDC 1, 2, 4, 16, and 50 and Appendix B to 10 C.F.R. Part 50. Although in this proceeding the Staff has issued the challenged license amendment prior to the hearing, this does not shift the burden of proof; the burden remains on NextEra. 155 150 Id.

151 Id.

152 See Duke Power Co. (Catawba Nuclear Station, Units 1 and 2), CLI-83-19, 17 NRC 1041, 1048 (1983) (citing Consumers Power Co. (Midland Plant, Units 1 and 2), ALAB-283, 2 NRC 11, 17 (1975)).

153 AmerGen Energy Company, LLC (Oyster Creek Nuclear Generating Station), CLI-09-7, 69 NRC 235, 262-63 (2009).

154 Id.; see Pac. Gas and Elec. Co. (Diablo Canyon Nuclear Power Plant, Units 1 and 2), ALAB-763, 19 NRC 571, 577 (1984) (to prevail on factual issues, the applicants position must be supported by a preponderance of the evidence); Tennessee Valley Authority (Hartsville Nuclear Plant, Units 1A, 2A, 1B, and 2B), ALAB-463, 7 NRC 341, 360 (1978), reconsideration denied, ALAB-467, 7 NRC 459 (1978)

(Absent some special statutory standard of proof, factual issues are determined by a preponderance of the evidence.).

155 See Crow Butte Res., Inc. (In Situ Leach Facility, Crawford, Nebraska), CLI-15-17, 82 NRC 33, 41 (2015) (stating that the issuance of a materials renewal license where a hearing was pending did not shift

II. NextEra Has Provided Reasonable Assurance that, with the License Amendment, as Conditioned, Seabrook Will Continue to Meet NRC Requirements As determined by the Staff in its SE of the LAR, NextEra has provided reasonable assurance (i.e., a preponderance of the evidence) that, with the license amendment, as conditioned, Seabrook will continue to meet the relevant NRC requirements of GDC 1, 2, 4, 16, and 50 and Appendix B to 10 C.F.R. Part 50 156 and, thus, will not endanger the health and safety of the public. 157 This is because, in part, (1) the conduct of the LSTP provided reasonable assurance that its data are representative and/or bounding of the progression of ASR at Seabrook and (2) NextEra appropriately used these LSTP data to develop the Seabrook ASR expansion monitoring program. The testimony of Angela Buford, Bryce Lehman, and George Thomas, as supported by the testimony of Jacob Philip, explains in detail why this is the case. 158 Based on this testimony, which is summarized below, the Board should rule that NextEra has satisfied its burden of demonstrating by a preponderance of the evidence that with the license amendment, as conditioned, Seabrook will continue to meet NRC requirements.

A. The Conduct of the LSTP Provided Reasonable Assurance that its Data Are Representative and/or Bounding of the Progression of ASR at Seabrook In response to the issue of ASR at Seabrook, NextEra developed the LSTP. As part of its development of the LSTP, NextEra first considered whether to use as the concrete for the test specimens concrete harvested from Seabrook or concrete made specifically for the the burden of proof because regardless of the issuance of the license, the burden remains on the applicant, and, with respect to NEPA compliance, on the Staff).

156 Exhibit INT024, SE encl. 2 at 60-61.

157 Id. at 64.

158 See generally Exhibits NRC001, Staff Testimony, and NRC005, Testimony of Jacob Philip.

LSTP. 159 NextEra decided on the latter approach because, although it did not use the exact concrete from Seabrook and it required the development of ASR quicker than at Seabrook, this approach allowed for the control of test variables, for testing beyond ASR levels exhibited in actual Seabrook structures, for including the structural context of the reinforced concrete component or system, and for the use of test methods consistent with the test data that were relied upon in developing the relevant code provisions. 160 Based on its determination of the areas for which there was potentially less margin at Seabrook or where existing performance data were lacking, NextEra then divided the LSTP into studies of (1) the performance of expansion and undercut anchors installed in concrete (i.e., the Anchor Test Program), (2) the shear capacity of reinforced concrete (i.e., the Shear Test Program), and (3) the reinforcement anchorage of rebar lap splices (i.e., bond strength) and flexural strength and stiffness (i.e., the Reinforcement Anchorage Test Program). 161 The LSTP also evaluated instruments and selected the SRBE for the measurement of through-thickness expansion (i.e., the Instrumentation Test Program). 162 The Staff reviewed the approach that NextEra selected and determined that, as conducted, the LSTP, in general, and each of its constituent test programs, in particular, provided reasonable assurance that the LSTPs data are representative and/or bounding of the progression of ASR at Seabrook.

159 Exhibit NRC001, Staff Testimony at A.20.

160 Id.

161 Id. at A.19.

162 Id.

i. The LSTP Was Representative and/or Bounding Overall, the LSTP involved fabricating multiple large-scale reinforced concrete test specimens, developing ASR in these specimens, and then load testing the specimens to failure to evaluate the impact of ASR in the structural context of a reinforced concrete component or system. 163 The Staff determined that these specimens were representative and/or bounding of reinforced concrete structures at Seabrook because they reflected the typical characteristics of ASR-affected structures at Seabrook. 164 Specifically, their large size represented the scale and structural context of structures at Seabrook and avoided uncertainties due to scaling effects associated with using smaller specimens. 165 The test specimens were also designed with reinforcement ratios and configurations similar to those at Seabrook. 166 Specifically, they used a two-dimensional rebar mat in the in-plane direction to simulate the rebar in the face of the typical walls at Seabrook. 167 This allowed the structural performance tests to account for the confinement effects provided by the typical Seabrook reinforcement configuration. 168 Further, the specimens dimensions and rebar were designed so that the specimens would best represent part of a larger structure. 169 Finally, the Staff determined that the concrete of the 163 Id.

164 Id. at A.23.

165 Id.; see Exhibit NRC005, Testimony of Jacob Philip at A.10.

166 Exhibit NRC001, Staff Testimony at A.23.

167 Id.

168 Id.

169 Id.

specimens itself reasonably reflected the properties of concrete in Seabrook structures. 170 For example, the concrete mix design for the specimens was based on specifications used at Seabrook (e.g., compressive strength, coarse aggregate gradation and type, water-to-cement ratio, cement type, aggregate proportions) and, in part, included constituents obtained from sources similar to those used during the construction of the plant. 171 The Staff also determined that the data obtained from the LSTP were representative and/or bounding of ASR-affected reinforced concrete structures at Seabrook because they were obtained across a range of ASR levels that exceeded and bounded the expansion seen to date at Seabrook and accounted for the effects of potential future expansion. 172 Additionally, the Staff determined that the LSTP used a sufficient number of tests and test specimens to provide reasonable assurance that its data were reliable. 173 The test methods and experimental designs used in the LSTP were consistent with the database of test data that was used to develop the relevant Seabrook design basis code equations. 174 The Staff determined that this similarity enabled a direct, representative comparison and assessment of the applicability and limitations of the code equations to determine the structural capacity of the range of ASR-affected Seabrook structures for the respective limit states. 175 170 Id.

171 Id.

172 Exhibit NRC001, Staff Testimony at A.23.

173 Id.

174 Id.

175 Id.

The LSTP established in-plane, through-thickness, and volumetric expansion limits, within which the Seabrook design basis codes would remain valid. 176 NextEra conservatively set the through-thickness and volumetric expansion limits at the maximum expansion observed on a test specimen from the Shear Test Program, which is more restrictive than the maximum observed in the Reinforcement Anchorage Test Program. 177 Therefore, the Staff determined that the expansion limits in the LAR are bounding for ASR-affected reinforced concrete structures at Seabrook.

Finally, to account for any potential observed differences in behavior in the future between ASR expansion in Seabrook structures as compared to ASR expansion in the LSTP, the Staff imposed a license condition that requires periodic confirmatory assessments of the ASR expansion behavior of Seabrook structures to ensure that it is similar to that observed in the LSTP. 178 Any issues identified by these periodic assessments will be entered into the Seabrook corrective action program and will be subject to NRC oversight. 179 The Staff determined that this provided additional assurance that the LSTP is representative.

For all of these reasons, as well as those discussed below with respect to each portion of the LSTP, the Staffs issuance of the amendment, as conditioned, was appropriate.

ii. The Anchor Test Program Was Representative and/or Bounding The Staff determined that the Anchor Test Program was representative and/or bounding of ASR-affected reinforced concrete structures at Seabrook for three reasons. First, it was 176 Id.

177 Id.

178 Exhibit NRC001, Staff Testimony at A.23.

179 Id.

performed consistent with the Seabrook design basis for anchor bolts. 180 Second, consistent with industry standards and accepted practices that the path through which load is transferred from an anchor to concrete is the primary consideration for the selection of representative anchors, the program used Hilti Kwik Bolt 3 expansion anchors (for the transfer of load from the bolt to the concrete using the frictional resistance of the expansion wedge on the concrete) and Drillco Maxi-Bolt undercut anchors (for the transfer of load to concrete using a positive bearing surface). 181 Hilti Kwik Bolt 3 expansion anchors are similar to the Hilti Kwik Bolt 1 and 2 anchors that have been previously installed at Seabrook and are presently the preferred torque-controlled expansion anchor at Seabrook; Drillco Maxi-Bolt is the only undercut anchor used at Seabrook. 182 Third, the program was performed at various levels of ASR expansion, on anchors installed before and after ASR development, and using a range of anchor sizes and embedment depths consistent with the anchor population at Seabrook. 183 iii. The Shear Test Program Was Representative and/or Bounding The Staff determined that the Shear Test Program was representative and/or bounding of ASR-affected reinforced concrete structures at Seabrook for four reasons. First, it used representative control and test specimens of differing levels of ASR. 184 Second, it used a large number of load tests to failure which were consistent with the applicable Seabrook design basis 180 Exhibit NRC001, Staff Testimony at A.24.

181 Id.

182 Id.

183 Id.

184 Exhibit NRC001, Staff Testimony at A.25.

code. 185 Third, it had test results that were all bounded by the strength calculated based on the ACI code provisions. 186 Fourth, it had test results that were consistent and repeatable. 187 Additionally, the Shear Test Programs results were similar to those reported in a recently published journal article. 188 iv. The Reinforcement Anchorage Test Program Was Representative and/or Bounding The Staff determined that the Reinforcement Anchorage Test Program was representative and/or bounding of ASR-affected reinforced concrete structures at Seabrook for four reasons. First, it used representative control and test specimens of differing levels of ASR that each contained reinforcement lap splices at the center constant moment region. 189 Second, it used a large number of load tests to failure. 190 Third, its results were consistent and repeatable. 191 Fourth, the flexure strength of the test specimens exceeded that of the control and the nominal flexural capacity calculated based on the ACI code provisions. 192 Additionally, 185 Id.

186 Id.

187 Id.

188 Id.; see NRC056, Madhu M. Karthik, et. al., Experimental Behavior of Large Reinforced Concrete Specimen with Heavy ASR and DEF [delayed ettringite formation] Deterioration, J. Struct. Eng. (2018)

(published online May 31, 2018).

189 Exhibit NRC001, Staff Testimony at A.26.

190 Id.

191 Id.

192 Id.

the Reinforcement Anchorage Test Programs results were similar to those reported in a recently published journal article. 193

v. The Additional Determinations Made Based, in Part, on the LSTP Were Representative and/or Bounding NextEra used the results of the LSTP, in combination with existing literature, to make additional determinations that the Staff found to also be representative and/or bounding of ASR-affected reinforced concrete structures at Seabrook.

With respect to compression, existing literature provides that ASR expansion does not reduce the compression capacity of confined concrete in its structural context. 194 The results of the Reinforcement Anchorage Test Program were consistent with this existing literature because if compression capacity had been reduced, a compression zone failure would have occurred in the specimens before the full flexural capacity was realized, but this did not happen. 195 Therefore, for the same reasons that the Reinforcement Anchorage Test Program was representative and/or bounding, the Staff determined that NextEras conclusion regarding compression was also representative and/or bounding of ASR-affected reinforced concrete structures at Seabrook within the expansion limits achieved during the testing. 196 With respect to reinforcement fracture, the existing literature identifies examples of reinforcement fracture in ASR-affected reinforced concrete structures, but only in bend 193 Id.; see NRC057, M. Kathleen Eck Olave, et. al., Performance of RC Columns Affected by ASR. II:

Experiments and Assessment, Vol. 20. ASCE J. of Bridge Engg (March 2015) (published online June 12, 2014).

194 Exhibit NRC001, Staff Testimony at A.27.

195 Id.

196 Id.

diameters smaller than those permitted by U.S. design codes. 197 FSEL performed bend tests of reinforcing bars bent to the allowable limits of Seabrook design codes and did not see evidence of compression crack formation. 198 Based on the combination of the existing literature and the results of the bend tests, NextEra concluded that ASR-affected reinforced concrete structures at Seabrook are not susceptible to brittle fracture. 199 The Staff agreed that this determination was bounding for Seabrook. 200 The LSTP also assessed the issue of seismic response. 201 The LSTP showed that, for heavily loaded members (i.e., members with flexural cracking), the flexural stiffness increased as ASR expansion increased within the expansion levels tested. 202 The Seabrook design basis seismic ground response spectrum shows that seismic demands decrease for frequencies larger than approximately 3 Hz. 203 Since all the structures at Seabrook have a natural frequency of at least 4 Hz and since an increase in stiffness will increase a structures frequency (considering no change in mass), the Staff noted that, for heavily loaded members, ASR will not have an adverse impact on seismic response. 204 Conversely, the LSTP showed that, for lightly loaded members (i.e., members with no flexural cracking), the flexural stiffness decreased as 197 Exhibit NRC001, Staff Testimony at A.28.

198 Id.

199 Id.

200 Id.

201 Exhibit NRC001, Staff Testimony at A.29.

202 Exhibit NRC007, UFSAR § 3.7(B); Exhibit INT024, SE, encl. 2 at 20; see Exhibit INT012, MPR-4288 (Rev. 0), Structure Deformation Report, fig. 6-1 at 6-6 (nonproprietary).

203 Exhibit NRC001, Staff Testimony at A.29; Exhibit INT024, SE, encl. 2 at 20.

204 Exhibit NRC001, Staff Testimony at A.29; Exhibit INT024, SE, encl. 2 at 20.

ASR expansion increased within the expansion levels tested. 205 However, since (1) all the structures at Seabrook have a natural frequency of at least 4 Hz, (2) the Seabrook seismic design uses a +/-10% peak broadening in the response spectra, and (3) there is a square root relationship between stiffness and natural frequency, the Staff noted that, for lightly loaded members, this reduction will not have a significant impact on the seismic response of the structure. 206 Therefore, the Staff concluded that the LSTP was bounding for Seabrook with respect to seismic response. 207 vi. The Instrumentation Test Program Provided Reasonable Assurance of Selection of Appropriate Instrument for Measuring Through-Thickness Expansion The Instrumentation Test Program evaluated, over a one-year period, three candidate instruments for measuring through-thickness expansion: a vibrating wire deformation meter (VWDM), an SRBE, and a hydraulic borehole extensometer. 208 The Program evaluated these instruments on a representative large-scale beam test specimen with regard to quality of data, ease of installation, and reliability. 209 The Program determined that the SRBE was the best instrument for measuring through-thickness expansion for six reasons. First, its data agreed 205 Id.

206 Id.

207 Id.

208 Exhibit NRC001, Staff Testimony at A.30; Exhibit INT024, SE, encl. 2 at 20 at 21; NRC008, MPR-4273 (Rev. 0) § 5.4.1 at 5-16 (nonproprietary); INT019-R, MPR-4273 (Rev. 1) § 5.4.1 at 5-16 (nonproprietary).

209 Exhibit NRC001, Staff Testimony at A.30; Exhibit INT024, SE, encl. 2 at 21; NRC008, MPR-4273 (Rev. 0) § 5.4.2 at 5-17-5-18 (nonproprietary); INT019-R, MPR-4273 (Rev. 1) § 5.4.2 at 5-17-5-18 (nonproprietary).

closely with the reference data. 210 Second, it directly measures physical expansion. 211 Third, it does not rely on additional equipment to function. 212 Fourth, it contains no electronics and does not require field calibration. 213 Fifth, it did not exhibit reliability problems. 214 Sixth, it was easier to install than the VWDMs. 215 The Staff determined that these test results provided reasonable assurance that the use of SRBEs to measure future through-thickness expansion of Seabrook structures would be effective. 216 In conclusion, the Staff determined that the conduct of the LSTP and its constituent test programs provides reasonable assurance that their determinations were representative and/or bounding of ASR-affected reinforced concrete structures at Seabrook. 217 Based, in part, on this, 210 Exhibit NRC001, Staff Testimony at A.30; Exhibit INT024, SE, encl. 2 at 21; NRC008, MPR-4273 (Rev. 0) § 5.4.2 at 5-17-5-18 (nonproprietary); INT019-R, MPR-4273 (Rev. 1) § 5.4.2 at 5-17-5-18 (nonproprietary).

211 Exhibit NRC001, Staff Testimony at A.30; Exhibit INT024, SE, encl. 2 at 21; NRC008, MPR-4273 (Rev. 0) § 5.4.2 at 5-17-5-18 (nonproprietary); INT019-R, MPR-4273 (Rev. 1) § 5.4.2 at 5-17-5-18 (nonproprietary).

212 Exhibit NRC001, Staff Testimony at A.30; Exhibit INT024, SE, encl. 2 at 21; NRC008, MPR-4273 (Rev. 0) § 5.4.2 at 5-17-5-18 (nonproprietary); INT019-R, MPR-4273 (Rev. 1) § 5.4.2 at 5-17-5-18 (nonproprietary).

213 Exhibit NRC001, Staff Testimony at A.30; Exhibit INT024, SE, encl. 2 at 21; NRC008, MPR-4273 (Rev. 0) § 5.4.2 at 5-17-5-18 (nonproprietary); INT019-R, MPR-4273 (Rev. 1) § 5.4.2 at 5-17-5-18 (nonproprietary).

214 Exhibit INT024, SE, encl. 2 at 21; NRC008, MPR-4273 (Rev. 0) § 5.4.2 at 5-17-5-18 (nonproprietary);

INT019-R, MPR-4273 (Rev. 1) § 5.4.2 at 5-17-5-18 (nonproprietary).

215 Exhibit NRC001, Staff Testimony at A.30; Exhibit INT024, SE, encl. 2 at 21; NRC008, MPR-4273 (Rev. 0) § 5.4.2 at 5-17-5-18 (nonproprietary); INT019-R, MPR-4273 (Rev. 1) § 5.4.2 at 5-17-5-18 (nonproprietary).

216 Exhibit NRC001, Staff Testimony at A.30; Exhibit INT024, SE, encl. 2 at 21.

217 Exhibit NRC001, Staff Testimony at A.30; Exhibit INT024, SE, encl. 2 at 21.

the Staff determined that NextEra has provided reasonable assurance that, with the license amendment, as conditioned, Seabrook will continue to meet NRC requirements. 218 B. NextEra Appropriately Used the LSTP Data to Develop the Seabrook ASR Expansion Monitoring Program The Seabrook ASR expansion monitoring program measures cracks in ASR-affected concrete, first in the in-plane direction using CI/CCI or CI/CCI supplemented by pin-to-pin expansion measurements and then, when in-plane expansion reaches a specified threshold, in the through-thickness direction using (1) a calculation to determine to-date expansion and (2) an SRBE to measure expansion thereafter. 219 The purpose of this monitoring is to ensure that the in-plane, through-thickness, and volumetric (the combination of in-plane and through-thickness expansions) expansions remain below expansion limits. 220 NextEra used the data from the LSTP to develop this ASR expansion monitoring program in three ways. First, the programs ASR expansion limits are from the LSTP. 221 As discussed above, the LSTP tested specimens with higher ASR levels than those present in Seabrook structures and there was no reduction in structural capacity at any of the levels tested. 222 Therefore, NextEra set the expansion limit as the highest expansion level experienced in the LSTP except where the highest expansion level experienced in one test was greater than the highest expansion level experienced in another test, in which case the lower of 218 Exhibit NRC001, Staff Testimony at A.30, A.53; Exhibit INT024, SE, encl. 2 at 21, 60-61.

219 Exhibit NRC001, Staff Testimony at A.15; Exhibit INT024, SE, encl. 2 at 21-22, 53-55.

220 Exhibit NRC001, Staff Testimony at A.15; Exhibit INT024, SE, encl. 2 at 21-22, 25, 53-55.

221 Exhibit NRC001, Staff Testimony at A.32, A.34.

222 Exhibit NRC001, Staff Testimony at A.19, A.38.

these two highest expansion levels was used as the expansion limit. 223 Based on the results of the LSTP and NextEras conservative use of the lower of two applicable expansion levels, the Staff determined that this approach was appropriate. 224 Second, NextEra set the point at which to transition from measuring in-plane expansion to measuring through-thickness expansion at 0.1%. 225 The Staff determined that this approach was appropriate because it corresponds to a low level of ASR degradation as determined by the LSTP. 226 Third, NextEra developed an equation to calculate through-thickness expansion to-date in Seabrook concrete. 227 The Staff determined that this calculation was appropriate because it was consistent with the LSTP data and the existing literature data and incorporated conservativisms. 228 Specifically, to develop the equation, NextEra reviewed data from the LSTP and from the existing literature and determined that the reduction in concrete elastic modulus is more sensitive to ASR development than other properties that have been studied. 229 Therefore, using the LSTP data, NextEra developed an equation to correlate normalized elastic modulus and through-thickness expansion. 230 NextEra compared literature data to this equation and 223 Exhibit NRC001, Staff Testimony at A.25, A.26, A.32.

224 Exhibit NRC001, Staff Testimony at A.32.

225 Id.

226 Id.

227 Id.

228 Id.

229 Id.

230 Exhibit NRC001, Staff Testimony at A.32.

noted that the trend from the literature data compared favorably with the equation. 231 Additionally, since the calculation of the normalized elastic modulus requires the calculation of the original (28-day) modulus of the impacted Seabrook concrete, either through estimation or the use of Seabrook concrete not impacted by ASR, NextEra applied a reduction factor to the normalized modulus, which conservatively overestimated expansion. 232 For these reasons, the Staff determined that the equation was appropriate.

In conclusion, NextEra appropriately used the LSTP data to develop the ASR expansion monitoring program. 233 Based, in part, on this determination, and the Staffs imposition of a license condition, the Staff concluded that NextEra has provided reasonable assurance that Seabrook will continue to meet NRC requirements.

III. C-10s Arguments Do Not Demonstrate that, with the License Amendment, as Conditioned, Seabrook Will Not Continue to Meet NRC Requirements The arguments of C-10 and its expert, Dr. Victor Saouma, do not alter the Staffs determination that NextEra has provided reasonable assurance (i.e., preponderance of the evidence) that, with the license amendment, as conditioned, Seabrook will continue to meet NRC requirements. The testimony of Angela Buford, Bryce Lehman, and George Thomas, as supported by the testimony of Jacob Philip, explains in detail why this is the case. 234 Based on this testimony, which is summarized below, the Board should rule that NextEra has satisfied its 231 Id.

232 Id.; Exhibit INT024, SE, encl. 2 at 22-23; Exhibit NRC011, MPR-4153 ASR Monitoring Report (Rev. 2)

§ 3.3.

233 Exhibit INT024, SE, encl. 2 at 31-32.

234 See generally Exhibits NRC001, Staff Testimony, and NRC005, Jacob Philip Testimony.

burden of demonstrating by a preponderance of the evidence that with the license amendment, as conditioned, Seabrook will continue to meet NRC requirements.

A. C-10s Argument Regarding the Representativeness of the LSTP Concrete Is Not Persuasive

i. C-10 Argument C-10 argues that the concrete used in the LSTP was not representative of the concrete at Seabrook because all the aggregates and all the sand used in the LSTP were not identical to those used in Seabrook and because NextEra did not state that the aggregates and sand came from the same quarry as Seabrooks. 235 C-10 argues that this is an important failure because the behavior of concrete is so sensitive to variables and that different sources of aggregates will result in drastically different concrete. 236 C-10 also states that it is problematic that the LSTP did not perform accelerated expansion tests of Seabrook and LSTP concrete cores, which would have allowed comparison of the cores to determine the extent to which the Seabrook and the LSTP concrete differed. 237 ii. Staff Response First, although not identical to the concrete at Seabrook, as discussed in Section II.A, supra, the Staff determined that the concrete used in the LSTP was sufficiently representative and/or bounding of the concrete at Seabrook such that the results of the LSTP could reasonably be applied to Seabrook. 238 Specifically, the concrete used in the LSTP had specifications 235 Exhibit INT001-R at 10.

236 Id.

237 Id.

238 Exhibit NRC001, Staff Testimony at A.38.

consistent with the specifications of the Seabrook concrete and used materials as similar to the original materials as reasonably possible. 239 Thus, the LSTP concrete was not drastically different from the Seabrook concrete as asserted by Dr. Saouma. 240 Moreover, the LSTP used concrete with ASR expansion greater than that currently present at Seabrook and, therefore, the limits derived from the LSTP are conservative. 241 Finally, to the extent that there are any substantive differences between the LSTP concrete and the Seabrook concrete, the Staff found that with the license condition imposed as a requirement for the issuance of the amendment, there is additional assurance that these differences will not affect the public health and safety. 242 Second, C-10 is essentially arguing that NextEra should have taken a different approach to addressing the issue of ASR at Seabrook (i.e., accelerated expansion tests instead of representative tests). 243 However, consistent with its regulations, when the Staff reviews a license amendment request, it does not determine whether the request could be achieved in some other, arguably better, manner; instead, its decision is guided by the considerations that govern the issuance of initial licenses. 244 These include finding that there is reasonable assurance that the activities authorized by the amendment can be conducted without endangering the health and safety of the public and that such activities will be conducted in 239 Id.

240 Id; see Exhibit INT001-R at 10.

241 Exhibit NRC001, Staff Testimony at A.38.

242 Exhibit NRC001, Staff Testimony at A.38.

243 See Exhibit INT001-R at 10-11, 36.

244 10 C.F.R. § 50.92(a).

compliance with the NRCs regulations. 245 Thus, to the extent that C-10 argues that the LAR could have been better, its argument is outside the scope of this proceeding. Moreover, NextEra did, in fact, evaluate as an alternative approach the testing of existing concrete harvested from Seabrook and rejected it as less preferable to the representative approach. 246 Taken together, C-10s arguments do not achieve what would be necessary to overturn the Staffs decisionthey do not show that NextEra has not provided reasonable assurance that, with the license amendment, as conditioned, Seabrook will continue to meet NRC requirements.

B. C-10s Argument Regarding Testing to Maximum Expansion Is Not Persuasive

i. C-10 Argument C-10 argues that the lack of accelerated expansion testing precludes NextEra from reaching any conclusions about the maximum likely degree of expansion. 247 ii. Staff Response C-10 is correct that NextEra did not run tests to estimate the remaining ASR expansion or to predict when ASR would stop occurring at Seabrook; however, C-10 does not explain why this is a safety concern. 248 NextEra has chosen a different engineering evaluation approach to ensure the safety of Seabrook structures that does not involve predictions of ASR kinetics and 245 10 C.F.R. § 50.57(a)(3).

246 Exhibit NRC001, Staff Testimony at A.20.

247 Exhibit INT001-R at 11, 26, 31.

248 Exhibit NRC001, Staff Testimony at A.50.

ultimate expansion. 249 The Staff determined that NextEra has identified reasonable and justifiable expansion limits, which account for potential future expansion, by setting the maximum level of expansion at which the code acceptance criteria are met. 250 Further, NextEra is actively monitoring structures to ensure that they remain within these limits. 251 The ultimate expansion of ASR at Seabrook is not relevant to the approach chosen by NextEra because under the approach selected in the LAR, NextEra will monitor the Seabrook structures to ensure that their expansion remains below the limits from the LSTP. 252 C. C-10s Arguments Regarding the Representativeness of the LSTP Test Specimens Are Not Persuasive C-10 argues that there were multiple errors in the LSTP with respect to specimen dimensions, loads, and boundary conditions. None of these arguments are persuasive

i. C-10 Arguments Regarding Modeling C-10 argues that the LSTP is not representative because NextEra failed to scale the test specimens to the dimensions of the Seabrook reactor; therefore, according to C-10, the corresponding load will not be representative. 253 C-10 also argues that the test specimens were not subjected to the same conditions (i.e., support, restraints, and load) as at Seabrook and that, therefore, the LSTP cannot be seen as a representative model for Seabrook. 254 For 249 Id.

250 Id.

251 Id.

252 Id.

253 Exhibit INT001-R at 11.

254 Id. at 11-12.

instance, C-10 argues that the LSTP assessed only the out-of-plane shear and not the in-plane shear and that the axial forces caused by the weight of the dome and the walls were not present in the test specimens. 255 ii. Staff Response Regarding Modeling These arguments regarding modeling are not relevant because the tests conducted in the LSTP used almost full-scale test specimens representative of a bounding reference location of a typical wall segment in a Seabrook ASR-affected seismic Category 1 structure (e.g., the B electrical tunnel). 256 The length and width of the specimens are the actual dimensions at the reference location and the height is that of a representative segment (or slice) of that location. 257 The specimens included two-dimensional reinforcement mats using the same reinforcement size and spacing, one along each longitudinal face, and with no shear reinforcement as in a typical wall at Seabrook. 258 The tests conducted in the LSTP were thus full-scale load tests to failure and not model tests, as asserted by C-10; therefore, there was no scaling involved. 259 Additionally, because the LSTP supplements (rather than replaces) the design code, results from appropriately representative test specimens may be applied to reinforced concrete structures throughout Seabrook. 260 255 Id. at 12-13.

256 Exhibit NRC001, Staff Testimony at A.39.

257 Id.

258 Id.

259 Id.

260 Id.

The LSTP did not test for the in-plane shear mode because the out-of-plane shear failure is bounding. 261 Additionally, it did not test for axial forces due to dead weight because they are compressive and have a beneficial effect on structural capacity in flexure and shear for in-situ structures such as those at Seabrook. 262 For these reasons, C-10s arguments do not alter the Staffs determination that NextEra has provided reasonable assurance that, with the license amendment, as conditioned, Seabrook will continue to meet NRC requirements.

iii. C-10 Arguments Regarding the Shear Test Program C-10 argues that, with respect to the Shear Test Program, if it had been properly performed, cracking would have occurred in the zone without reinforcement. 263 According to Dr.

Saouma, however, the load-displacement curve in MPR-4273, Rev. 1, Figure 5-5 264 is not indicative of a shear failure with minimum or no reinforcement and, therefore, some shear reinforcement is present. 265 Specifically, pointing to his Figure 5, Dr. Saouma argues that what likely happened was a crack in the zone of the beam with the shear reinforcement. 266 261 Id. at A.40.

262 Id.

263 Exhibit INT001-R at 13.

264 Exhibit INT021, MPR-4273, LSTP Report (Rev. 1), fig. 5-5 at 5-7 (proprietary).

265 Exhibit INT001-R at 13-14.

266 Id. at 14.

C-10 also argues that the unanticipated crack shown in MPR-4273, Rev. 1, Figure 4-2 267 should be of the utmost concern as it jeopardizes the representativeness of the ensuing test and would cause the results to be unreliable. 268 iv. Staff Response Regarding the Shear Test Program The Shear Test Program used 3-point load tests. 269 Figure 5 of Dr. Saoumas testimony is an inaccurate depiction of the Shear Test Program because in the program, the left support of the beam was located to the right of the end area with stirrups and, therefore, contrary to Dr.

Saoumas assertion, the programs test span did not include any shear stirrups. 270 ACI 318-71 determines shear capacity (strength) based on the onset of diagonal (tension) or inclined cracking, 271 which occurred in the Shear Test Programs specimens at the blip[s], as Dr.

Saouma calls them, 272 in Figure 5-5 of MPR-4273. 273 Accordingly, these points were determined to be the shear capacity. The fact that the curve proceeds, as Dr. Saouma states, 274 is not unexpected. On the contrary, the fact that a new shear carrying mechanism, 267 Exhibit INT021, MPR-4273, LSTP Report (Rev. 1), fig. 4-2 at 4-4 (proprietary).

268 Exhibit INT001-R at 15-16.

269 Exhibit NRC001, Staff Testimony at A.41.

270 Id.

271 Exhibit NRC049, American Concrete Institute (ACI) Standard 318-71, Building Code Requirements for Reinforced Concrete §§ 11.4.1, 11.4.2, 11.2.3, 11.2.4 (1971) (ACI 318-71).

272 Exhibit INT-001-R at 14.

273 Exhibit INT021, MPR-4273, LSTP Report (Rev. 1), fig. 5-5 at 5-7 (proprietary).

274 Exhibit INT-001-R at 14.

which is capable of sustaining further load, can develop in a reinforced concrete beam without shear reinforcement after the formation of diagonal cracks is well known in the literature. 275 Separately, as ASR progressed in the test specimen, FSEL observed a relatively large crack near the center of the surfaces between the reinforcement mats, as depicted in Figure 4-2 of MPR-4273. 276 Contrary to Dr. Saoumas statement that this crack jeopardizes the representativeness of the ensuing test, 277 NextEra confirmed that this crack was an edge effect that penetrated only a few inches into the specimen. 278 This did not compromise the representativeness of the test region because away from the edges, expansion was of about the same magnitude but distributed into finer cracks across the specimen cross sections. 279 Additionally, such an edge effect crack is not expected to occur in Seabrook structures due to confinement effects provided by adjoining structural members. 280 For these reasons, C-10s arguments do not alter the Staffs determination that NextEra has provided reasonable assurance that, with the license amendment, as conditioned, Seabrook will continue to meet NRC requirements.

275 Exhibit NRC001, Staff Testimony at A.41; see Exhibit NRC072, R. Park and T. Paulay, Reinforced Concrete Structures, at 256 (John Wiley & Sons, Inc. 1975); Exhibit NRC073, David Darwin, Charles W.

Dolan, and Arthur H. Nilson, Design of Concrete Structures at 138-141 (McGraw Hill, Inc., 15th Ed.

2016).

276 Exhibit NRC001, Staff Testimony at A.42; Exhibit INT021, MPR-4273, LSTP Report (Rev. 1), fig. 4-2 at 4-4 (proprietary).

277 Exhibit INT001-R at 16.

278 Exhibit INT021, MPR-4273, LSTP Report (Rev. 1) at 4-4-4-5 (proprietary); Exhibit NRC001, Staff Testimony at A.42.

279 Exhibit NRC001, Staff Testimony at A.42.

280 Id.

v. C-10 Arguments Regarding Assumptions C-10 argues that NextEra confuses material strength with structural strength. 281 C-10 also argues that NextEras proposal to add ASR as a design basis load is a serious error because the assumption that ASR can be considered a load is fundamentally wrong. 282 vi. Staff Response Regarding Assumptions C-10s argument that NextEra confuses material strength with structural strength is not relevant to the acceptability of the LAR. 283 The LSTP showed what is well known in existing ASR literaturethat, when affected by ASR, material properties of concrete are degraded. 284 The purpose of the LSTP, however, was not to tie material strength to structural strength, but, rather, to demonstrate that although concrete material properties may be degraded, the structural performance of the reinforced concrete member can still be conservatively estimated by the design basis code equations within the ASR levels experienced in the LSTP. 285 Thus, NextEra is not confusing material strength with structural strength, it is relying on the LSTP results to demonstrate that structural strength is unaffected as long as the expansion remains below the LSTP limits, regardless of the reductions in material strength. 286 C-10s argument that ASR cannot be considered a load is also not persuasive. C-10 is correct that the demands on a structure are the loads applied to the structure, while the capacity 281 Exhibit INT001-R at 17.

282 Id.

283 Exhibit NRC001, Staff Testimony at A.43.

284 Id.

285 Id.

286 Id.

of a structure is its ability to resist loads. 287 Although ASR reduces material properties of unreinforced concrete, the LSTP results showed that ASR, within the LSTP limits, does not reduce the capacity of reinforced concrete structural members. 288 However, restraint to ASR expansion does apply a self-equilibrating internal tensile force to the reinforcement and an internal compressive force to the concrete, which produces additional demand that must be resisted by the structure. 289 NextEra acknowledged this load and chose to address it by adding it to the design basis load combinations as a self-straining load in structural analyses performed in support of the building deformation monitoring program. 290 For these reasons, C-10s arguments do not alter the Staffs determination that NextEra has provided reasonable assurance that, with the license amendment, as conditioned, Seabrook will continue to meet NRC requirements.

vii. C-10 Arguments Regarding SE Statements C-10 argues that the SEs statements that (1) limits at Seabrook can be derived from the LSTP and (2) ASR degradation is monitored as it progresses are not supportable. 291 viii. Staff Response Regarding SE Statements These arguments fail for several reasons. First, as discussed in detail in Section II.A, supra, the Staff determined that the LSTP was sufficiently representative and/or bounding of Seabrook such that there is reasonable assurance that the use of LSTP data at Seabrook will 287 Id. at A.44.

288 Id.

289 Exhibit NRC001, Staff Testimony at A.44.

290 Id.

291 Exhibit INT001-R at 18-19.

not endanger the health and safety of the public. Specifically, the LSTP was designed and conducted such that it achieved ASR effects (e.g., expansion, cracking, etc.) in test specimens that are representative and/or bounding of the effects on actual Seabrook structures. 292 The lower of the highest expansion levels, without impact on structural capacity, achieved in the LSTP were conservatively chosen as expansion limits at Seabrook. 293 Therefore, as long as ASR expansion at Seabrook remains within these limits, structural capacity determined using code equations remains valid. 294 Second, the ASR expansion monitoring program does require the monitoring of ASR as it progresses. 295 The interval for this monitoring is based on the progression of crackingwhen there is no indication of pattern cracking or water ingress (i.e., Tier 1), the inspection frequency is as prescribed in the Seabrook structural monitoring program (generally every 5 years for structures in environments likely to promote ASR); when there are areas with pattern cracking that cannot be accurately measured or in-plane expansion of 0.05% (i.e., Tier 2), the inspection frequency is 30 months; and when there is in-plane expansion of 0.1% or more (i.e., Tier 3), the inspection frequency is 6 months. 296 The Staff determined that five years is an acceptable, conservative monitoring frequency for structures, as indicated in industry guidance documents, such as ACI 349.3R, Evaluation of Existing Nuclear Safety-Related Concrete Structures. 297 292 Exhibit NRC001, Staff Testimony at A.45.

293 Id.

294 Id.

295 Id. at A.34.

296 Id. at A.15 297 Id. at A.34; see Exhibit NRC059, ACI 349.3R, Evaluation of Existing Nuclear Safety-Related Concrete Structures (2002) (Reapproved 2010).

The Staff also determined that six months is a conservative inspection interval for structures, regardless of the degradation mechanism, and ASR is a very slowly progressing degradation mechanism. 298 Moreover, NextEra is required by the license condition to conduct assessments of expansion behavior to confirm that future expansion behavior of ASR-affected structures at Seabrook is comparable to what was observed in the LSTP and monitoring could be adjusted as necessary based on these assessments. 299 Based on the foregoing, there is reasonable assurance that, with the limits and monitoring periodicity derived from the LSTP, operations at Seabrook will continue to meet NRC requirements.

ix. C-10 Arguments Regarding CI/CCI C-10 argues that, as a monitoring measure, CI/CCI must be ruled out completely. 300

x. Staff Response Regarding CI/CCI This argument is not persuasive. CI/CCI is a commonly used conservative method for monitoring crack progression or in-plane expansion due to ASR, as discussed in ASR-monitoring specific guidance documents. 301 Dr. Saouma argues, by reference to Figure 1 in the FHWA Report, 302 that Section 2.2 of this report indicates that CI/CCI can only be used in 298 Exhibit NRC001, Staff Testimony at A.34.

299 Id. at A.33; Exhibit INT024, SE, encl. 2 at 59-60.

300 Exhibit INT001-R at 21.

301 Exhibit NRC001, Staff Testimony at A.46; Exhibit NER013, U.S. Department of Transportation, Federal Highway Administration, Report on the Diagnosis, Prognosis, and Mitigation of Alkali-Silica Reaction (ASR) in Transportation Structures (FHWA-HIF-09-004) (Jan. 2010) (FHWA Report).

302 Although Dr. Saouma refers to this Figure as Figure 12, the cited figure is Figure 1 in the FHWA Report. Exhibit NER023, FHWA Report at 5.

conjunction with petrography. 303 Dr. Saouma, however, fails to recognize that Section 2.2 of the FHWA Report is entitled, ASR Investigation Program Level 2: Preliminary Studies for the Diagnosis of ASR, and the portion of its Figure 1 to which he refers is also marked as Level 2 Preliminary Investigation Program. 304 Therefore, the context of the FHWA Reports recommendation to use petrography in addition to CI/CCI only relates to the early detection and diagnosis of ASR in concrete. 305 This guidance, though, is not relevant to Seabrook because ASR has already been diagnosed and confirmed at Seabrook based on the petrographic examination of cores and because NextEra considers any future visual indications of concrete degradation to be due to ASR. 306 Moreover, the FHWA Report does recognize CI/CCI as an in-situ method that gives a quantitative assessment of the extent of cracking in structural members, which is related to the overall amount of expansion reached in the affected concrete member. 307 The FHWA Report notes that CI/CCI provides a quantitative rating of the surface deterioration affecting the structure as a whole. 308 The FHWA Report includes CI/CCI and monitoring of deformations/movements as recommended in-situ methods that can be used for estimating the expansion to date in ASR-affected concrete members. 309 This is exactly what was done by 303 Exhibit INT001-R at 19-20.

304 Exhibit NER023, FHWA Report at 3, 5.

305 Exhibit NRC001, Staff Testimony at A.46.

306 Id.

307 Id.; Exhibit NER023, FHWA Report at 23.

308 NER023, FHWA Report at 23.

309 NER023, FHWA Report at 32, 31.

NextEraat Seabrook, CI/CCI is used to estimate the expansion-to-date in the in-plane direction of ASR-affected structures. 310 Additionally, NextEra installed permanent pins in the boundaries of the CI grids to serve as DEMEC mechanical strain gauge points for more accurate future expansion measurements. 311 Therefore, the use at Seabrook of CI/CCI, or baseline CI/CCI in combination with subsequent pin-to-pin measurements, to characterize and monitor the progression of in-plane ASR expansion is consistent with industry practice. 312 Additionally, the use of CI/CCI is conservative because cracking is always more pronounced on the free surface of a structure because that is where it is most free to develop and grow. 313 Further, although surface cracking can also be influenced by other mechanisms such as temperature variation, drying and wetting cycles, and shrinkage, all the cracking is attributed to ASR. 314 Dr. Saouma states that at Seabrook temperature is much lower on the surface of the wall, and there is a thermal gradient with the much warmer concrete inside and the relative humidity [of the surface of the walls] is much reduced[; h]owever, the inside of the concrete would maintain a high one. 315 Therefore, to Dr. Saoumas thinking, should cracking be noticeable through CI/CCI this would imply that the internal swelling was so great that it 310 Exhibit NRC001, Staff Testimony at A.46.

311 Id.

312 Id.

313 Id.

314 Id.

315 Exhibit INT001-R at 21.

affected the surface cracking. 316 This argument is incorrect: internal ASR expansion that has no visual manifestations on the surface is not significant with regard to structural performance. 317 Expansion of any significance will manifest on the surface in the form of cracking, spalling, pop-outs, relative displacements, or deformation long before any impact to structural performance. 318 Moreover, field evidence from cores that were removed at Seabrook has not shown any indications of structural concern in the concrete interior. 319 Therefore, the use of CI/CCI at Seabrook provides reasonable assurance of adequate protection of the public health and safety. 320 Dr. Saouma argues that additional petrographic studies should be conducted to characterize the out-of-plane or through-thickness expansion that occurs in a plane parallel to the surface and is not reflected in the CI/CCI. 321 Dr. Saouma suggests that the Damage Rating Index (DRI) method should be used. 322 The FHWA Report notes that, while the DRI method may be useful for quantitative assessment of internal damage in concrete, there is no standard procedure for this method. 323 The method is fairly subjective and the results can be quite 316 Id.

317 Exhibit NRC001, Staff Testimony at A.46.

318 Id.

319 Id.

320 Id.

321 Exhibit INT001-R at 20, 31.

322 Id. at 20, 32.

323 Exhibit NER023, FHWA Report at 96.

variable from one petrographer to another. 324 Dr. Saouma hints at this in his testimony when he caution[s] that [DRI] is a delicate test that should only be performed by a very qualified petrographer, and should be performed repeatedly by the same one. 325 Instead of relying on a delicate test and only one dedicated petrographer, NextEra employs an SRBE installed to a depth almost through the entire thickness of the concrete member (i.e., within a few inches of the far surface) to monitor through-thickness expansion progression. 326 The Staffs review of the SRBE method of measuring through-thickness expansion found that this approach is effective. 327 The Staff notes that the SRBE method provides a much more accurate and meaningful measure of through-thickness expansion than the subjective petrographic DRI method. 328 Finally, Dr. Saouma states that no serious researcher would rely on [CI as an indicator of ASR]. 329 This argument is not relevant to this proceeding, however, because the LAR does not rely on CI/CCI as an indicator of ASR; rather, it assumes that any concrete degradation is due to ASR. 330 324 Id.

325 Exhibit INT001-R at 31.

326 Exhibit NRC001, Staff Testimony at A.46.

327 Id.

328 Exhibit NRC001, Staff Testimony at A.30.

329 Exhibit INT001-R at 26.

330 Exhibit NRC001, Staff Testimony at A.48.

For these reasons, C-10s arguments do not alter the Staffs determination that NextEra has provided reasonable assurance that, with the license amendment, as conditioned, Seabrook will continue to meet NRC requirements.

D. C-10s Arguments Regarding the Structure Deformation Monitoring Program Are Not Within the Scope of this Proceeding As discussed above, the LAR involves two distinct activitiesASR expansion monitoring and structure deformation monitoring. The scope of an admitted contention is defined by its terms and by the bases addressed by a licensing board in making its admissibility decision. 331 The terms of the contention at issue in this proceeding make explicit that it has to do with the LSTP. 332 C-10s arguments regarding the structure deformation monitoring program, however, have to do with portions of the program that do not have a connection to the LSTP. 333 Therefore, as a matter of law, these arguments are outside the scope of this proceeding and should not be addressed by the Board.

The structure deformation monitoring program does not rely on LSTP data as direct numerical input for the structural analysis to determine the structural demand under design basis loads including ASR. 334 The LSTP provides the technical basis and expansion limits for using the code-based approach and the structural capacity acceptance criteria against which 331 NextEra Energy Seabrook, LLC (Seabrook Station, Unit 1), CLI-12-5, 75 NRC 301, 309-10, 310 n.50 (2012) ([A]n admitted contention is defined by its bases and the Commission assume[s] that any basis not addressed by the Board was not relied upon in making its admissibility decision.); Entergy Nuclear Generation Co. (Pilgrim Nuclear Power Station), CLI-10-11, 71 NRC 287, 309 (2010) (The reach of a contention necessarily hinges upon its terms coupled with its stated bases.) (internal quotation marks omitted)).

332 LBP-17-7, 86 NRC at 90.

333 Exhibit NRC001, Staff Testimony at A.17.

334 Id.

the structural demands are compared for applicable limit states. 335 But the LSTP does not influence the structural demands calculated by the structural analyses conducted as part of the structure deformation monitoring program. 336 NextEras determination that, in general, ASR expansion in reinforced concrete imparts an additional compressive stress or load on the concrete in directions where expansion is restrained by the reinforcing steel (i.e., ASR load) is based on existing literature, which was confirmed by the LSTP. 337 As part of the structure deformation monitoring program, the ASR load developed for each ASR-affected structure at Seabrook is estimated based on field data from the actual structures and is not derived from the LSTP. 338 Specifically, the structure deformation monitoring program uses Cl/CCI (or baseline Cl/CCI supplemented by pin-to-pin expansion measurements) to estimate the ASR strain in a concrete member. 339 The structure deformation monitoring program may also use other appropriate field measurements (e.g.,

seismic gaps, annulus gaps, relative displacements, etc.) and observations using commonly used measurement tools. 340 In conclusion, the only overlap of the structure deformation monitoring program with the LSTP is that the programs acceptance criteria are tied to the point at which a structure would 335 Id.

336 Id.

337 Id.

338 Id.

339 Exhibit NRC001, Staff Testimony at A.17.

340 Id.

meet the limits identified in the LSTP. 341 However, the entire process used in the structure deformation monitoring program up to this point, including finite element analyses, is separate from the LSTP. 342 Therefore, since C-10s contention has to do with the representativeness of the LSTP, the process used in the structure deformation monitoring program, such as the performance of finite elements analyses, is outside the scope of this proceeding and only the limits that are shared between the ASR expansion monitoring program and the structure deformation monitoring program are at issue in this proceeding. 343 C-10 attempts to get around this conclusion regarding the scope of this proceeding by pointing out that the ASR expansion monitoring program refers to the structure deformation monitoring program. Specifically, Dr. Saouma points out that Table 5 of the LAR provides that the recommended actions for Tier 3 structures, those with in-plane expansion of 0.1%, are enhanced ASR monitoring and a [s]tructural evaluation. 344 This, though, does not, as Dr.

Saouma claims, make the process used in the structure deformation monitoring program an integral part of ASR expansion monitoring; 345 rather, the term [s]tructural evaluation is simply a pointer for the Seabrook staff to initiate a process (or evaluation) separate from the ASR expansion monitoring programs process. 346 Stated another way, when in-plane expansion reaches 0.1%, the ASR expansion monitoring program triggers two follow-on actions(1) 341 Id.

342 Id.

343 Id.

344 Exhibit INT010, LAR at 33 (unnumbered); Exhibit INT001-R at 24.

345 Exhibit INT001-R at 24.

346 Exhibit NRC001, Staff Testimony at A.47.

implementing enhanced ASR monitoring under the ASR expansion monitoring program (i.e.,

installing an SRBE to measure through-thickness expansion) and (2) initiating structural evaluation under the structure deformation monitoring program. 347 This [s]tructural evaluation follows the separate process described in Sections 3.3 and 3.5.2 of the LAR and summarized in the separate Table 6 of the LAR. 348 Thus, the [s]tructural assessment under the structure deformation monitoring program is only triggered by, but not a part of, the ASR expansion monitoring program. 349 Dr. Saouma also tries to conflate the two programs by noting that Section 3.5.2 of the LAR is titled Structure Deformation and not [S]tructure [D]eformation Monitoring, 350 but this does not somehow mean that Section 3.5.2 is a part of the ASR expansion monitoring program. 351 On the contrary, a plain language reading of the LAR indicates that Section 3.5.2 has to do with only the structure deformation monitoring program and not the ASR expansion monitoring programSection 3.5 is titled Monitoring and it is broken up into Section 3.5.1, ASR Expansion [Monitoring], and Section 3.5.2, Structure Deformation [Monitoring]. 352 In conclusion, C-10 has no support for its conflation of the structure deformation and ASR expansion monitoring programs. 353 The scope of this proceeding is limited to the 347 Id.

348 Id.; see Exhibit INT010, LAR at 34 (unnumbered).

349 Exhibit NRC001, Staff Testimony at A.47.

350 Exhibit INT001-R at 23.

351 Exhibit NRC001, Staff Testimony at A.47.

352 Id.; Exhibit INT010, LAR at 30, 31, 33 (unnumbered).

353 Exhibit NRC001, Staff Testimony at A.47.

representativeness of the LSTP, and the simple assertion that the structure deformation monitoring program is a part of the ASR expansion monitoring program does not show that the process used in the structure deformation monitoring program relies on the LSTP. On the contrary, the aspects of the structure deformation monitoring program that C-10 challenges (e.g., finite element analysis) do not rely on the LSTP. 354 Therefore, the Board should ignore the issues that C-10 raises with respect to the structure deformation monitoring program.

E. C-10s Arguments Regarding the Structure Deformation Monitoring Program Are Not Persuasive Even if the Board were to address the issues that C-10 raises with respect to the structure deformation monitoring program, it should find that they do not alter the Staffs determination that NextEra has provided reasonable assurance that, with the license amendment, as conditioned, Seabrook will continue to meet NRC requirements. This is because, first, all of C-10s arguments are based on Simpson, Gumpertz, & Heger, Inc.,

Evaluation and Design Confirmation of As-Deformed CEB, 150252-CA-02, Revision 0, July 2016; 355 whereas, the LAR was based on a substantially revised version (Revision 2) of this report. 356 Second, as explained in detail below, none of C-10s individual arguments are persuasive.

354 Id.

355 Exhibit INT001-R at 24-28; see Exhibit INT015, Simpson Gumpertz & Heger, Inc., "Evaluation and Design Confirmation of As-Deformed CEB, 150252-CA-02," Revision 0, July 2016 (Seabrook FP#100985) Enclosure 2 to Letter SBK-L-16153, re: Seabrook Station (Sept. 30, 2016) (ML16279A049).

356 Exhibit NRC001, Staff Testimony at A.48.

i. C-10 Argument Regarding Linear Elastic Analysis C-10 argues that ASR and its impact at Seabrook cannot be analyzed using linear elastic methods. 357 ii. Staff Response Regarding Linear Elastic Analysis In the Seabrook licensing design basis, reinforced concrete structures were designed so that the behavior of the structure is in the small deformation elastic range under design basis loads and load combinations. 358 Specifically, for containment, the structural acceptance criteria in the Seabrook UFSAR, Section 3.8.1.5, state that [t]he containment structure, including liner and penetrations, was designed to remain within elastic limits under service load conditions and under the mechanical loads of the factored load conditionsThe design limits imposed on the various parameters that serve to quantify the structural behavior and provide a margin of safety are in compliance with Article CC-3000 of [the ASME Code,Section III,] Division 2. 359 The ASME Code,Section III, Division 2 uses the working stress design philosophy. 360 For containment internal structures and other seismic Category 1 structures, the structural acceptance criteria in the Seabrook UFSAR, Sections 3.8.3.5 and 3.8.4.5 state that they were proportioned to maintain elastic behavior under all normal and unusual load conditions. 361 The upper bound of elastic behavior was taken as the yield strength capacity of the load carrying 357 Exhibit INT001-R at 24-26, 36.

358 See generally Exhibit NRC007, UFSAR at § 3.8.

359 Id. § 3.8.1.5.

360 Exhibit NRC001, Staff Testimony at A.48; Exhibit NRC050, Section Ill, Division 2, of the 1975 Edition of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code) at 183-216.

361 Exhibit NRC001, Staff Testimony at A.48; Exhibit NRC007, UFSAR, at § 3.8.4.5.

components. 362 Reinforced concrete structures (other than containment) were designed in accordance with the ACI 318-71 strength design method. 363 NextEras proposed approach to analyze ASR-affected structures at Seabrook maintains the same criteria that the behavior of the structures and structural components (as a reinforced concrete system) will remain within the upper bound of elastic behavior under all design load combinations, including the ASR load. 364 The results of the LSTP provided additional technical basis to support NextEras proposed approach. 365 Specifically, the load-deformation plots of the representative ASR-affected large-scale structural beam specimens that were tested to failure generally showed linear behavior up to the point of flexural yielding (in the Reinforcement Anchorage Test Program) or initiation of the diagonal crack (in the Shear Test Program) similar to the behavior of the control specimens and the assumptions in the code. 366 Based on this information, the Staff determined that it was reasonable for NextEra to use linear elastic methods to analyze ASR-affected structures at Seabrook. 367 The Staff also determined that it was reasonable for NextEra to use the original design methods to evaluate existing structures, provided that the original design assumptions were maintained and the effects of any observed degradation of significance (e.g., ASR effects) were 362 Exhibit NRC001, Staff Testimony at A.48; NRC049, ACI 318-71 at §§ 8.1.1, 8.1.3.

363 Id. at § 3.8.4.5.

364 Exhibit NRC001, Staff Testimony at A.48.

365 Id.

366 Id.; see Ex. INT020, INT020, MPR-4253, ASR Monitoring Report (Rev. 3), fig. 5-5 at 5-7, fig. 5-7 at 5-11 (proprietary).

367 Exhibit NRC001, Staff Testimony at A.48.

reasonably accounted for (i.e., so that capacity was greater than or equal to load effects). 368 The LSTP results indicated that the behavior of ASR-affected structures may be considered to be bounded by original design methods, that is, that the code equations provide a lower bound estimate of structural capacity of ASR-affected concrete members. 369 This conclusion is consistent with those made based on large-scale testing by other researchers. 370 Based on this information, and the Staffs determination that the LSTP is representative of Seabrook, ASR and its impact at Seabrook can be analyzed using linear elastic methods.

iii. C-10 Argument Regarding Probabilistic Based Analysis C-10 argues that a probabilistic based analysis should be performed for the Seabrook structural evaluation because of the high risks associated with an accident at Seabrook and the uncertainties associated with capacity and demand. 371 iv. Staff Response Regarding Probabilistic Based Analysis As stated previously, it is not relevant to the Staff review that the proposed approach could have been done differently. The Staff found that the methodology and supporting bases proposed by NextEra in the LAR is one acceptable approach for evaluating whether Seabrook structures affected by ASR meet regulatory requirements and that its results provided reasonable assurance that the Seabrook ASR-affected structures remain capable of performing 368 Id.

369 Id.

370 Id.; see Exhibit NRC074, Stéphane Multon, et. al., Flexural Strength of Beams Affected by ASR, 12th International Conference on Alkali-Aggregate Reaction, Beijing, China (2004) at § 6; Exhibit NRC075, Dean J., Deschenes, et. al., ASR/DEF-Damaged Bent Caps: Shear Tests and Field Implications, Technical Report No. 12-8XXIA006 summarizing work conducted for the Texas Department of Transportation at Ferguson Structural Engineering Laboratory, The University of Texas at Austin (August 2009) at 226.

371 Exhibit INT001-R at 29.

their intended safety functions. 372 Therefore, C-10s argument that a better approach is available, without more, is not relevant to this proceeding. 373 F. C-10s Argument Regarding Peer Review and In-House Expertise Is Not Persuasive C-10 states that peer review is a cornerstone of engineering practice and that peer reviewers must (1) be sufficiently detached from the project organization (i.e., not ultimately report to the same hierarchy), (2) be familiar with the literature, and (3) have a degree of scientific expertise and rigor that is sufficient to enable them to credibly comment. 374 C-10 then faults the NRC for not having such peer reviews. 375 Separately, C-10 faults NextEra and its contractors for having no in-house expertise on ASR. 376 C-10s argument that the NRC must perform peer reviews and that NextEra must have an in-house ASR expert is not persuasive for the simple reason that there are no such requirements with respect to license amendment requests. 377 Moreover, C-10 does not demonstrate why these things would be necessary for the Staff to reach the finding that is, in fact, required, which is that NextEra has provided reasonable assurance that, with the license amendment, as conditioned, Seabrook will continue to meet NRC requirements. 378 Instead, as explained above, based on all of the information that it had gathered regarding ASR at 372 Exhibit NRC001, Staff Testimony at A.49.

373 Id.

374 INT001-R at 35.

375 Id.

376 Id. at 36.

377 Exhibit NRC001, Staff Testimony at A.52.

378 Id.

Seabrook since 2009, including through NextEras submission of the LAR and its license renewal application, and the many supplements to these filings, and through inspections, audits, RAIs, and public meetings, the Staff has comprehensively reviewed the issue of ASR at Seabrook and has appropriately determined that, as conditioned, the LAR should be issued. 379 The Staff also gathered additional information to support its review of the ASR issue at Seabrook through mechanisms that largely meet the three elements that C-10 asserts constitute a peer review. 380 First, the ACRS, an independent, statutorily mandated committee, 381 reviewed the issue. 382 The ACRS is composed of highly qualified professionals. 383 As part of its review of the ASR issue at Seabrook, the ACRS reviewed all of the relevant materials and met with and asked questions of the Staff and NextEra. 384 Second, a different Staff office, the Office of Nuclear Regulatory Research, provided an independent review of the validity of the LSTP. 385 For these reasons, C-10s arguments do not alter the Staffs determination that NextEra has provided reasonable assurance that, with the license amendment, as conditioned, Seabrook will continue to meet NRC requirements.

379 Id.

380 Id.

381 42 U.S.C. § 2039.

382 Exhibit NRC048, Corradini Letter at 1.

383 See ACRS Membership, https://www.nrc.gov/about-nrc/regulatory/advisory/acrs/membership.html (last visited July 24, 2019).

384 Exhibit NRC048, Corradini Letter at 1.

385 Exhibit INT024, SE, encl. 2 at 30-31. RES assigned to this task one of its members with expertise in concrete, see Exhibit NRC006, Statement of Professional Qualifications of Jacob Philip, and that member reviewed the documentation relevant to the LSTP. See Exhibit NRC005, Jacob Philip Testimony, at A.5, A.6.

CONCLUSION As determined by the Staff in its safety evaluation of the LAR, NextEra has provided reasonable assurance that, with the license amendment, as conditioned, Seabrook will continue to meet NRC requirements. None of C-10s arguments credibly dispute this determination.

Therefore, the Board should uphold the Staffs issuance of the LAR.

Respectfully submitted,

/Signed (electronically) by/

Jeremy L. Wachutka Counsel for the NRC Staff U.S. Nuclear Regulatory Commission Mail Stop O14-A44 Washington, DC 20555 Telephone: (301) 287-9188 E-mail: Jeremy.Wachutka@nrc.gov Executed in Accord with 10 CFR 2.304(d)

Anita Ghosh Naber Counsel for the NRC Staff U.S. Nuclear Regulatory Commission Mail Stop O14-A44 Washington, DC 20555 Telephone: (301) 415-0764 E-mail: anita.ghoshnaber@nrc.gov Executed in Accord with 10 CFR 2.304(d)

Jennifer E. Scro Counsel for the NRC Staff U.S. Nuclear Regulatory Commission Mail Stop O14-A44 Washington, DC 20555 Telephone: (301) 287-9081 E-mail: Jennifer.Scro@nrc.gov Dated at Rockville, Maryland this 24th day of July 2019

UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In the Matter of NEXTERA ENERGY SEABROOK, LLC Docket No. 50-443-LA-2 (Seabrook Station, Unit 1)

CERTIFICATE OF SERVICE Pursuant to 10 C.F.R. § 2.305, I hereby certify that copies of the foregoing NRC STAFF INITIAL WRITTEN STATEMENT OF POSITION, dated July 24, 2019, have been filed through the Electronic Information Exchange, the NRCs E-Filing System, in the above-captioned proceeding, this 24th day of July 2019.

/Signed (electronically) by/

Jeremy L. Wachutka Counsel for the NRC Staff U.S. Nuclear Regulatory Commission Mail Stop O14-A44 Washington, DC 20555 Telephone: (301) 287-9188 E-mail: Jeremy.Wachutka@nrc.gov Dated at Rockville, Maryland this 24th day of July 2019