ASLBP 17-953-02-LA-BD01, Initial Decision (Ruling on the Reformulated Contention) (LBP-20-09)

Initial Decision (Ruling on the Reformulated Contention) (LBP-20-09)

ML20254A339
Person / Time
Site:	Seabrook
Issue date:	08/21/2020
From:	Sekazi Mtingwa, Ronald Spritzer, Nicholas Trikouros Atomic Safety and Licensing Board Panel
To:	NRC/OGC, NextEra Energy Seabrook
SECY RAS
References
50-443-LA-2, ASLBP 17-953-02-LA-BD01, LBP-20-09, RAS 55786
Download: ML20254A339 (207)

Text

Official Use Only Proprietary Information LBP-20-09 UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION ATOMIC SAFETY AND LICENSING BOARD Before Administrative Judges:

Ronald M. Spritzer, Chairman Nicholas G. Trikouros Dr. Sekazi K. Mtingwa In the Matter of Docket No. 50-443-LA-2 NEXTERA ENERGY SEABROOK, LLC ASLBP No. 17-953-02-LA-BD01 (Seabrook Station, Unit 1) August 21, 2020 INITIAL DECISION (Ruling on the Reformulated Contention)

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Official Use Only Proprietary Information TABLE OF CONTENTS I. Introduction ............................................................................................................................ 1 II. Background............................................................................................................................ 3 A. Discovery and Evaluation of ASR at Seabrook .............................................................. 3 B. C-10s Petition and the Boards Ruling on Standing and Contention Admissibility......... 8 C. C-10s Emergency Motion ............................................................................................ 14 D. Plant Tour ..................................................................................................................... 16 E. Evidentiary Hearing ...................................................................................................... 17 F. Motion to Compel Mineralogical Data ........................................................................... 18 III. Legal Standards................................................................................................................... 21 A. Regulatory Framework ................................................................................................. 21

1. Seismic Category I Structures ...................................................................................... 21

2. Updated Final Safety Analysis Report, Section 3.8 ...................................................... 22

3. License Amendments ................................................................................................... 24 B. Legal Standards Governing this Proceeding ................................................................ 29

1. Burden of Proof ............................................................................................................ 29 IV. Seabrook License Amendment ............................................................................................ 31 A. NRC Staff Safety Evaluation ........................................................................................ 31 B. NRC Staff Technical Conclusions ................................................................................ 32 C. License Condition ......................................................................................................... 34 D. License Renewal .......................................................................................................... 35 V. Summary of the Parties Statements of Position ................................................................. 36 A. C-10 .............................................................................................................................. 36 B. NextEra ......................................................................................................................... 38 C. NRC Staff ..................................................................................................................... 39 VI. Witnesses ............................................................................................................................ 41 A. Qualifications of Witnesses .......................................................................................... 41

1. C-10s Expert Witness .................................................................................................. 41

2. NextEra Expert Witnesses ............................................................................................ 42

3. NRC Staff Expert Witnesses ........................................................................................ 46 B. Admissibility/Weight of Expert Testimony ..................................................................... 49 VII. Motions in Limine ................................................................................................................. 52 A. Proper Scope of Rebuttal Testimony ............................................................................ 54 B. License Renewal .......................................................................................................... 59 C. Evidence from C-10s Emergency Petition ................................................................... 60 VIII. Findings of Fact and Board Analysis of Disputed Issues ..................................................... 62 A. Representativeness of the LSTP .................................................................................. 62

1. General Findings Related to Representativeness ........................................................ 62

2. Concrete ....................................................................................................................... 73

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a. Motion in Limine ........................................................................................................ 74

b. C-10s Prima Facie Case .......................................................................................... 82

c. NextEra and Staff Responses ................................................................................... 88

d. Findings of Fact and Board Analysis ........................................................................ 91

3. Test Specimen Scaling, Reinforcement, and Size ....................................................... 98

a. Motion in Limine ........................................................................................................ 98

b. C-10s Prima Facie Case ........................................................................................ 102

c. NextEra and Staff Responses ................................................................................. 104

d. Findings of Fact and Board Analysis ...................................................................... 107

4. Boundary Conditions .................................................................................................. 111

a. Motion in Limine ...................................................................................................... 111

b. C-10s Prima Facie Case ........................................................................................ 111

c. NextEra and Staff Responses ................................................................................. 112

d. Findings of Fact and Board Analysis ...................................................................... 116

5. Effect of Reinforcement (Use of Original Material Properties) .................................... 116

a. Motion in Limine ...................................................................................................... 117

b. C-10s Prima Facie Case ........................................................................................ 119

c. NextEra and Staff Responses ................................................................................. 122

d. Findings of Fact and Board Analysis ...................................................................... 125

6. Summary of Board Conclusions on Representativeness Issues ................................ 129 B. ASR Monitoring Intervals ............................................................................................ 129

1. C-10s Prima Facie Case ............................................................................................ 130

2. NextEra and Staff Responses .................................................................................... 131

3. Findings of Fact and Board Analysis .......................................................................... 134 C. Accelerated Expansion Tests and Alternative Methodologies .................................... 141

1. Motion in Limine ......................................................................................................... 141

2. C-10s Prima Facie Case ............................................................................................ 146

3. NextEra and Staff Responses .................................................................................... 148

4. Findings of Fact and Board Analysis .......................................................................... 153

a. Ultimate ASR Expansion/Representativeness ........................................................ 153

b. Monitoring Intervals and Sigmoid Curve ................................................................. 155

c. Threshold Expansion/Acceptance Limits ................................................................ 158 D. Corroboration Study ................................................................................................... 160

1. C-10s Prima Facie Case ............................................................................................ 163

2. NextEra and Staff Responses .................................................................................... 164

3. Findings of Fact and Board Analysis .......................................................................... 167 E. Concrete Delamination and Localized Excursions Outside the Linear Elastic Regime 170

1. Motion in Limine ......................................................................................................... 171

2. C-10s Prima Facie Case ............................................................................................ 174

3. NextEra and Staff Responses .................................................................................... 177

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4. Findings of Fact and Board Analysis .......................................................................... 181 F. C-10s Remaining Issues Are Outside the Scope of the Proceeding ......................... 186

1. Deformation Monitoring .............................................................................................. 186

2. Inadequate Peer Review ............................................................................................ 189

3. Steel Corrosion ........................................................................................................... 190 G. Unaddressed Issues ................................................................................................... 192 IX. Conclusion ......................................................................................................................... 192 A. Summary of Board Holdings and License Conditions ................................................ 192 B. Review of the Boards Decision .................................................................................. 193 APPENDIX .................................................................................................................................... a

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Official Use Only Proprietary Information LIST OF ABBREVIATIONS ACI American Concrete Institute ACRS Advisory Committee on Reactor Safeguards ASME American Society of Mechanical Engineers ASR Alkali-Silica Reaction ASTM American Society of Testing and Materials C-10 C-10 Research and Education Foundation, Inc.

CEB Containment Enclosure Building CI Cracking Index CCI Combined Cracking Index DRI Damage Rating Index EPRI Electric Power Research Institute FEA Finite Element Analysis FHWA U.S. Department of Transportation Federal Highway Administration FSB Fuel Storage Building FSAR Final Safety Analysis Report FSEL Ferguson Structural Engineering Laboratory GDC General Design Criteria ISE Institution of Structural Engineers LAR License Amendment Request LSTP Large-Scale Test Program mm/m millimeters per meter MPR MPR Associates, Inc.

NRC U.S. Nuclear Regulatory Commission NRR NRC Office of Nuclear Reactor Regulation NSHCD No Significant Hazards Consideration Determination NUREG NRC Technical Report Designation OBE Operating Basis Earthquake PDF Portable Document Format POD Prompt Operability Determination RAI Request for Additional Information RES NRC Office of Nuclear Regulatory Research SE Safety Evaluation SEM Structural Evaluation Methodology SGH Simpson, Gumpertz, & Heger Inc.

SMP Structures Monitoring Program

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Official Use Only Proprietary Information SSCs Structures, Systems, and Components SSE Safe Shutdown Earthquake UFSAR Updated Final Safety Analysis Report

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Official Use Only Proprietary Information I. Introduction This proceeding arose from a license amendment request (LAR) filed by NextEra Energy Seabrook, LLC (NextEra), 1 regarding the operating license for Seabrook Unit 1, in Seabrook, New Hampshire. The LAR revised the Unit 1 Updated Final Safety Analysis Report (UFSAR) to include methods for analyzing the impact of concrete degradation caused by the alkali-silica reaction (ASR) affecting seismic Category I reinforced concrete structures at Seabrook. 2 On April 10, 2017, C-10 Research & Education Foundation, Inc. (C-10) timely filed a petition seeking a hearing on the LAR. 3 In LBP-17-7, this Board held that C-10 established its standing to intervene in this proceeding, and admitted Contentions A, B, C, D, and H, as modified by the Board. Under 10 C.F.R. §§ 2.319(j) and 2.329(c)(1) and pursuant to 1 Ex. INT010, Seabrook, License Amendment Request 16 Revise Current Licensing Basis to Adopt a Methodology for the Analysis of Seismic Category I Structures with Concrete Affected by Alkali-Silica Reaction (August 1, 2016) at PDF 1-3 [hereinafter Ex. INT010, Original LAR]. Ex. INT010, Original LAR is a 74-page unnumbered portable document format (PDF) file.

For reference clarity, this Board will refer to all Original LAR pages using their PDF page numbers.

We note also that the exhibit number references we use in this proceeding begin with a three-letter party identifier, i.e., NER (for LAR applicant NextEra), NRC (for the NRC Staff), and INT (for intervenor C-10 Research & Education Foundation, Inc (C-10)), followed by the exhibit number, and then followed in some instances by the designator -R to indicate that the exhibit was revised after its original submission as a pre-filed exhibit.

2 See id. at PDF 2. Seismic Category I structures, systems, and components (SSCs) include those necessary to control the release of radioactive material or otherwise mitigate the consequences of an accident. We shall occasionally refer to these seismic Category I structures simply as Seabrook structures. See Ex. NRC088, Regulatory Guide (RG) 1.29, Seismic Design Classification for Nuclear Power Plants (July 2016) at 5 [hereinafter Ex.

NRC088, RG 1.29].

3 C-10 is a membership organization with more than 700 members. Its name has been shortened from the original, Citizens within the 10-Mile radius (of Seabrook Station) to C-10.

The organization is a non-profit 501(c)(3) membership organization with the mission to protect public health and the environment surrounding Seabrook Station. C-10 Research and Education Foundation, Inc. Petition for [L]eave to [I]ntervene: Nuclear Regulatory Commission Docket No. 50-443 (Apr. 10, 2017) at 1 [hereinafter C-10 Petition]; [C-10] Response to U.S.

NRC Staffs Ans. to [C-10]s Petition for Leave to Intervene: Nuclear Regulatory Commission Docket No. 50-443 (May 12, 2017) at 2 [hereinafter C-10s Reply].

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Official Use Only Proprietary Information Commission precedent, 4 the Board combined Contention D with portions of Contentions A, B, C, and H that each alleged defects in the LARs monitoring program, acceptance criteria, and inspection intervals. 5 The reformulated contention states:

The large-scale test program, undertaken for NextEra at the [Ferguson Structural Engineering Laboratory], 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. 6 On March 11, 2019, the NRC Staff (Staff) issued the license amendment to NextEra Energy Seabrook, LLC. 7 On September 24-27, 2019, the Board conducted an evidentiary hearing on the reformulated contention at the Newburyport City Hall Auditorium in Newburyport, Massachusetts. 8 This Initial Decision resolves the reformulated contention, which is based on Contentions A, B, C, D, and H. In Part VIII, infra, we identify several aspects of the LAR that, if unaltered, would preclude a finding that the license amendment provides reasonable assurance of adequate protection of public health and safety (hereinafter reasonable assurance). 9 We further 4 Section 2.319(j) authorizes a Board to [h]old conferences before or during a hearing for . . .

[the] simplification of contentions, while 10 C.F.R. § 2.329(c)(1) authorizes a Board to hold a prehearing conference to consider matters including the [s]implification, clarification, and specification of the issues. See Shaw AREVA MOX Servs (Mixed Oxide Fuel Fabrication Facility), LBP-08-11, 67 NRC 460, 481-83 (2008) (describing licensing boards authority to reformulate contentions); see also Crow Butte Res. Inc. (North Trend Expansion Project), CLI-09-12, 69 NRC 535, 552 n.79 (2009).

5 LBP-17-7, 86 NRC 59, 127 (2017).

6 Id. at 90.

7 Ex. INT024, NRC Safety Evaluation Related to Amendment No. 159 to Facility Operating License No. NPF-86 (March 11, 2019) at 2 [hereinafter Ex. INT024, Final SE]. For clarity, this Board will reference the PDF page numbers in citations to this exhibit.

8 See Tr. at 214-1203.

9 See Atomic Energy Act § 182, 42 U.S.C. § 2232. Both the common standards for licenses and construction permits in 10 C.F.R. § 50.40(a), and those specifically for issuance of operating licenses in 10 C.F.R. § 50.57(a), provide that there must be reasonable assurance that the activities at issue will not endanger the health and safety of the public. Entergy Nuclear Operations, Inc. (Palisades Nuclear Plant), CLI-15-22, 82 NRC 310, 316 n.44 (2015).

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Official Use Only Proprietary Information conclude, however, infra Part IX.A, that the imposition of license conditions on these aspects of the LAR provides reasonable assurance. The license conditions include modifications to conditions imposed by the Staff 10 when it granted the LAR and modifications to the requirements of NextEras ASR monitoring program. With the inclusion of the Board conditions in the license amendment, we conclude that it satisfies regulatory requirements. We therefore resolve the reformulated contention in favor of NextEra.

II. Background A. Discovery and Evaluation of ASR at Seabrook ASR is one type of alkali-aggregate reaction that can damage and degrade concrete structures. 11 The expansion of concrete and cracking from ASR can potentially impact the capacity 12 (i.e., structural properties) of a concrete structure by reducing the material properties (i.e., compressive strength, elastic modulus, and tensile strength) 13 of the concrete. 14 Concrete expansion caused by ASR can also lead to deformation of the structure itself and cause strains where the expansion is resisted by steel reinforcement or supports, other structures, or adjoining parts of the same structure that are outside the ASR-affected area. 15 Structural deformation caused by ASR can increase the load or demand on the structure, which, in turn, affects overall structural performance. 16 10 See infra Part IX.A.

11 Ex. INT010, Original LAR at PDF 8-9. The reaction is explained in more detail infra Part II.A.

ASR and many other technical terms are defined in the Glossary, see infra app.

12 Capacity is the ability to withstand applied loads, such as from an earthquake. Ex. NER001, MPR Testimony at 36.

13 Id. at 39.

14 See id.

15 Ex. INT010, Original LAR at PDF 23.

16 Id. at PDF 9-10.

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Official Use Only Proprietary Information NextEra first identified pattern cracking consistent with ASR at Seabrook in 2009. 17 Cracking was initially identified in the B Electrical Tunnel, 18 and, subsequently, in several other seismic Category I structures at the facility. 19 As a result, NextEra removed multiple concrete cores from the walls in several plant structures to confirm the presence of ASR. 20 In August 2010, NextEra completed the petrographic evaluation 21 of the concrete core samples, which confirmed ASR as the degradation mechanism. 22 The degraded conditions of Seabrook seismic Category I structures were evaluated in the plants Corrective Action Program via a prompt operability determination (POD) in August 2010 23 that later went through several revisions. 24 In 2012, NextEra completed an interim evaluation that assessed the structural adequacy of the reinforced concrete structures affected by ASR and the system/component anchorages in the ASR-affected concrete. 25 The evaluation found that the affected reinforced concrete structures would remain suitable for continued 17 Id. at PDF 9.

18 Id.

19 Id.

20 Id.

21 Petrographic examination involves microscopic examination of prepared concrete surfaces by a qualified petrographer. The examination assesses the overall quality of concrete, and can determine causes for concrete degradation. Ex. NER001, MPR Testimony at 48.

22 Ex. NER018, MPR-3727, Rev. 1, Seabrook Station: Impact of Alkali-Silica Reaction on Concrete Structures and Attachments (Jan. 2014) and NextEra Supplements I-V Thereto (FP100716, Rev. 4) at 12 [hereinafter Ex. NER018, MPR-3727].

23 Ex. NRC019, Confirmatory Action Letter, Seabrook Station, Unit 1 - Information Related to Concrete Degradation Issues (May 16, 2012) at 2.

24 The initial PODs (Revisions 0 and 1) addressed the B Electrical Tunnel where ASR was first discovered. Five other buildings were identified as part of the extent-of-condition review and the evaluation of core samples taken from these structures. The PODs were updated as new information became available and revised analytical techniques were incorporated. See Ex.

NRC082, Letter from Paul O. Freeman, NextEra, to NRC, Seabrook Station Actions for Resolution of Alkali Silica Reaction (ASR) Issues (May 10, 2012) at 2-3.

25 Ex. INT010, Original LAR at PDF 10.

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Official Use Only Proprietary Information service for an interim period. 26 However, the evaluation noted that additional testing was required to evaluate the full design compliance of the concrete structures. 27 On August 1, 2016, NextEra submitted its LAR. 28 The LAR revised the Seabrook Unit 1 UFSAR to include methods for analyzing the impact of concrete degradation caused by ASR on seismic Category I reinforced concrete structures. 29 The changes also limited allowable ASR expansion and established criteria for monitoring future changes due to ASR expansion and related structural deformation. 30 The three key elements of the LAR included the Large-Scale Test Program (LSTP), 31 the Structures Monitoring Program (SMP), and the Structural Evaluation Methodology (SEM). We will review each of these in turn.

Because the applicable building codes do not include provisions for the analysis of structures affected by ASR, 32 NextEra devised its own methodology and concluded that, despite the effect of ASR on the material properties of Seabrook concrete, Seabrook structures will have strength close to or in excess of that envisaged in the original design or as required by the code. 33 NextEra based its methodology on the LSTP and its review of the existing technical literature. 34 The LSTP involved testing concrete specimens constructed by MPR Associates, 26 Id.

27 Id.

28 Id. at PDF 2.

29 Id. at PDF 8.

30 Id. at PDF 16-17, 30-37; see also id. at PDF 16-17.

31 The LAR uses the terms large-scale test programs and large-scale test program interchangeably. See e.g., id. at PDF 15. In addition, some of the exhibits referenced in this order refer to the test program as the large-scale test programs, the FSEL, or the MPR/FSEL, but all refer to the same LSTP performed by FSEL. We will use the phrase LSTP throughout, regardless of how it was originally stated.

32 Id. at PDF 11.

33 Id. at PDF 15.

34 Id. at PDF 10.

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Official Use Only Proprietary Information Inc. (MPR)a consultant to NextErathat purportedly reflected the structural characteristics of ASR-affected structures at Seabrook. 35 NextEra concluded that the LSTP was a better means to evaluate ASRs impact on structural performance than testing cores taken directly from the Seabrook Plant. 36 The Ferguson Structural Engineering Laboratory (FSEL), part of the University of Texas at Austin, performed the tests on the constructed specimens. 37 The specimens used in the LSTP had ASR levels more severe than those found at Seabrook, but the number of available test specimens and nature of the testing prohibited testing out to ASR levels where there was a clear change in limit state capacity. 38 Because of the lack of testing data for more advanced levels of ASR, periodic monitoring of ASR at Seabrook is necessary to ensure that the conclusions of the [LSTP] remain valid and that the level of ASR does not exceed that considered under the test programs. 39 The LAR, therefore, identified methods for monitoring ASR expansion. The SMP as modified by the LAR includes:

(1) periodic measurement of ASR expansion[;] and (2) periodic inspections of ASR-affected structures to identify and trend building deformation. 40 35 Id. at PDF 15.

36 See Ex. NRC001-R, Staff Testimony at 24 [hereinafter Ex. NRC001-R, Staff Testimony].

37 Ex. INT010, Original LAR at PDF 15.

38 Id. at PDF 17. A limit state is a condition of a structure beyond which it no longer fulfills the relevant design criteria. Id. at PDF 15.

39 Id. at PDF 17.

40 Id. at PDF 30-31. The SMP performs two functions. First, the program gathers expansion measurements from crack width measurements and extensometer readings at Seabrook for monitoring against specified acceptance criteria based on the LSTP to determine whether ASR-related expansion at Seabrook exceeds levels observed in the LSTP. Second, it gathers crack width and deformation measurements for monitoring against criteria established in the structural evaluations performed under the Structural Evaluation Methodology. Ex. NER001, Testimony of NextEra Witnesses Michael Collins, John Simons, Christopher Bagley, Oguzhan Bayrak, and Edward Carley (MPR Testimony) at 59, 111-12, 113 [hereinafter Ex. NER001, MPR Testimony]; Ex. NER007, Seabrook Structures Monitoring Program Manual, Rev. 7

[PROPRIETARY] at 4-1.2 [hereinafter Ex. NER007, Seabrook [SMP] Manual Rev. 7] (non-public). The specific monitoring methods are discussed in more detail infra Part VIII.A.

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Official Use Only Proprietary Information The SEM evaluates both structural capacity and demands, or loads, 41 placed on the structures. 42 On the capacity side, the SEM uses Seabrooks existing UFSAR provisions on concrete capacities with the original design concrete specifications, so long as the Expansion Monitoring Limits in the SMP are not exceeded. 43 On the demand side, NextEras evaluation concluded that ASR expansion in reinforced concrete resulted in a compressive load that should be combined with other loads already included in design calculations. 44 The LAR, therefore, included an analytical approach to account for the effects of ASR on design basis loads. 45 The SEM provides a methodology for calculating the ASR loads on a structure, based on in-plane expansion measurements such as crack width, pin-to-pin mechanical, and structural deformation measurements. 46 NextEra proposed several modifications to the Seabrook UFSAR to account for loads from ASR expansion in design calculations. 47 Incorporating the loads into 41 Loads are [f]orces or other actions that result from the weight of all building materials, occupants and their possessions, environmental effects, differential movements, and restrained dimensional changes. Permanent loads are loads in which variations over time are rare or of small magnitude. All other loads are variable loads. Ex. NER004, Testimony of NextEra Witnesses Said Bolourchi, Glenn Bell, and Matthew Sherman (SGH Testimony) at 22

[hereinafter Ex. NER004, SGH Testimony].

42 See id. at 15-20, 42-43.

43 Id. at 17, 19-20; Ex. NER001, MPR Testimony at 60.

44 Ex. INT010, Original LAR at PDF 20 tbl.2.

45 Id. at PDF 16-17, 18-19, 23-30. Seabrooks original licensing basis includes methods for performing structural evaluations on Seabrooks Containment Building and certain other structures at the plant to ensure that they fulfill their safety-related functions following a design basis earthquake. Ex. NER001, MPR Testimony at 19.

46 Ex. NER004, SGH Testimony, at 15-20, 32, 42-43; see generally Ex. INT022, Simpson Gumpertz & Heger, Methodology for the Analysis of Seismic Category I Structures with Concrete Affected by Alkali-Silica Reaction (June 2018) [hereinafter Ex. INT022, SEM]. Ex.

INT022, SEM is a 175-page PDF with multiple pagination forms. For reference clarity, the Board will cite to PDF page numbers.

47 See Ex. INT010, Original LAR at PDF 24-30; Ex. NRC007, UFSAR § 3.8.

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Official Use Only Proprietary Information the UFSAR and evaluating structures using the appropriate properties for ASR-affected structural members is a change in methodology that requires NRC review and approval. 48 As part of its SEM, NextEra uses a computational approach called a Finite Element Analysis (FEA) to understand the complex structures at Seabrook. 49 The FEA is a computational model that includes various elements to collectively . . . simulate the structural geometry, stiffness, and mass of the desired structure. 50 Modelers can add loads (i.e.,

demands), such as gravity, wind, or ASR, to the FEA to measure structural responses. 51 NextEras stated goal in using the FEA is to determine the structural forces, stresses, and deformations in the structural elements when required loadings are applied. 52 The FEA provides a methodology for calculating the ASR loads on a structure based on field measurements and structural deformation measurements. 53 After computing the total demands from ASR and other factors in the FEA, those demands are compared to the structural capacities (in this case, the capacities calculated using code equations and original material properties) to determine whether the structural integrity is within acceptable limits. 54 B. C-10s Petition and the Boards Ruling on Standing and Contention Admissibility On February 7, 2017, the NRC published a Federal Register notice of opportunity to request a hearing on the LAR. 55 In that notice, the Staff proposed to determine that the 48 See infra Parts III.A.2-A.3.

49 Ex. NER004, SGH Testimony at 21-22, 39-40.

50 Id. at 39.

51 Id. at 39-40.

52 Id. at 39.

53 Id. at 19-22, 44.

54 Id. at 21-22, 39-40.

55 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).

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Official Use Only Proprietary Information amendment request involves no significant hazards consideration under 10 C.F.R. § 50.92(c). 56 On April 10, 2017, C-10 timely filed a petition seeking a hearing on the LAR submitted by NextEra concerning the operating license for Seabrook. 57 C-10s Petition included ten contentions (Contentions A-J), 58 which outlined its concerns surrounding ASR-induced concrete degradation and its potential impacts on the concrete structures reinforcing the facility. 59 On May 5, the Staff and NextEra filed answers to the Petition. 60 NextEra argued that C-10 failed to submit an admissible contention. 61 Although the Staff maintained that none of the original contentions, standing alone, were admissible, 62 it proposed that a reformulated contention that combined C-10s Contentions A, B, C, D, G, and H would be admissible. 63 The Staff maintained that C-10s remaining contentions were inadmissible. 64 C-10 did not object to the admission of the reformulated contention. 65 In LBP-17-7, this Board admitted five contentions (Contentions A, B, C, D, and H) from the Petition. 66 The Board found each of those contentions to be at least partially independently 56 Id.

57 C-10 Petition at 1.

58 Id. at 2-3.

59 Id.

60 NRC Staffs Ans. to [C-10] Petition for Leave to Intervene (May 5, 2017) [hereinafter Staff Ans. to Petition]; NextEras Ans. Opposing [C-10]s Petition for Leave to Intervene and Hearing Request on [NextEra]s License Amendment Request 16-03 (May 5, 2017) [hereinafter NextEra Ans. to Petition].

61 NextEra Ans. to Petition at 16.

62 Staff Ans. to Petition at 26.

63 Id.

64 Id.

65 LBP-17-7, 86 NRC 59, 89 (2017), affd, CLI-18-4, 87 NRC 89 (2018).

66 See LBP-17-7, 86 NRC at 92-131.

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Official Use Only Proprietary Information admissible. 67 The details of each contention are set forth in detail in LBP-17-7, 68 but because the parties dispute the scope of the issues admitted for hearing, we provide a summary of each admitted contention below.

Contention A stated that [v]isual inspection, crack width indexing, and extensometer deployment are not sufficient tools for determining the presence and extent of ASR in safety-related structures at Seabrook Station. 69 The Board concluded that Contention A was inadmissible to the extent it concerns visual inspections because the LARs monitoring program does not depend on visual inspections. 70 But the Board found Contention A admissible as to the use of a combined cracking index (CCI) to monitor in-plane expansion (parallel to the underlying rebars) 71 and the use of extensometers to measure through-thickness 72 expansion (perpendicular to the underlying rebars). 73 C-10s proposed Contention B stated that [e]xpansion occurring within a reinforced concrete structure due to [ASR] is not equivalent to a [prestressing] effect. Any mitigation of lost structural capacity, due to reinforcement, is temporary and unpredictable. 74 According to C-10, NextEras claim that ASR-impacted concrete held under restraint by steel rebar increases in 67 Id. at 126-27.

68 Id. at 92-137.

69 C-10 Petition at 2.

70 LBP-17-7, 86 NRC at 95.

71 Ex. INT010, Original LAR at PDF 16.

72 Several terms have been used during this proceeding to discuss through-thickness expansion, such as radial and horizontal expansion. Both terms are synonymous with through-thickness expansion. For clarity, we will use the phrase through-thickness, although exhibits and witnesses may have used a different phrase.

73 LBP-17-7, 86 NRC at 95; Ex. INT010, Original LAR at PDF 16.

74 C-10 Petition at 4 (emphasis omitted). Prestressing of concrete refers to the approach of applying a compressive load to improve the tensile capacity of the concrete member. . . .

Because concrete is much stronger in compression than tension, prestressing can improve in-service performance for certain applications. Ex. NER001, MPR Testimony at 38.

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Official Use Only Proprietary Information strength reflects a false understanding of the forces at work. 75 C-10 asserted that the concrete may show a temporary increase in certain measures of strength, but irrevocably will advance toward failure. 76 According to C-10, [t]he danger in misconstruing the effects of ASR, acting within the restraint imposed by reinforcing steel, is that serious degradation . . . may go unnoticed without employing thorough petrographic analysis. 77 The Board concluded that C-10s argument was sufficient to establish a significant link between the claimed deficiency and the agencys ultimate determination whether the applicant will adequately protect the health and safety of the public. 78 The Board agreed with the Staff, however, that it need not resolve the theoretical question whether ASR-induced expansion within a reinforced concrete structure causes an effect that is equivalent to prestressing. 79 The Board, therefore, restated Contention B to read:

The LAR misconstrues expansion occurring within a reinforced concrete structure due to the Alkali-Silica Reaction because any mitigation of lost structural capacity, due to reinforcement, is temporary and unpredictable. 80 Contention C repeated Contention Bs demand for thorough petrographic analysis of Seabrook structures, along with the argument that the benefit from ASR expansion in reinforced concrete is only temporary because microcracking will eventually lead to an autocatalytic collapse of the concretes properties. 81 The Board admitted Contention C because it provided additional expert arguments in support of C-10s demand for thorough petrographic analysis. 82 75 Id. at 5.

76 Id. (emphasis omitted).

77 Id. (emphasis omitted).

78 LBP-17-7, 86 NRC at 106.

79 Id. at 105.

80 Id. at 107.

81 C-10 Petition at 8.

82 LBP-17-7, 86 NRC at 108-11.

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Official Use Only Proprietary Information Contention D, quoting the LAR, emphasized that [a]pplication of the results of the

[LSTP] requires that the test specimens be representative of reinforced concrete at Seabrook Station, and that expansion behavior of concrete at the plant be similar to that observed in the test specimens. 83 Contention D alleged that the LSTP yielded data not truly representative of the non-linear advancement of ASR over the course of 35-40 years in Seabrook concrete. 84 Contention D further emphasized that the LSTP could not be substituted for the required comprehensive petrographic analysis of in-situ concrete at the Seabrook reactor. 85 The Board concluded that if Contention D is correct, reliance on the LSTP to support the proposed monitoring program, acceptance criteria, and inspection intervals undermines the LAR. 86 The Board, therefore, concluded that Contention D is admissible. 87 Contention H stated that the monitoring intervals NextEra proposed for Tier 2 88 and Tier 3 89 areas were too long and too fixed to measure effectively the ongoing impacts of ASR on seismic Category I structures. 90 C-10 claimed that there was no real knowledge of the speed of concrete deterioration caused by advancing ASR, i.e., there [was] no determination as to 83 C-10 Petition at 9 (quoting Ex. INT019, MPR-4273, Rev. 1, Seabrook Station - Implications of Large-Scale Test Program Results on Reinforced Concrete Affected by Alkali-Silica Reaction (March 2018) (Enclosure 7 to Letter SBK-18072) at vi [hereinafter Ex. INT019, MPR-4273]; Ex.

INT021, MPR-4273, MPR-4273, Rev. 1, Seabrook Station - Implications of Large-Scale Test Program Results on Reinforced Concrete Affected by Alkali-Silica Reaction (March 2018)

(Enclosure 7 to Letter SBK-18072) at vi [hereinafter Ex. INT021, MPR-4273] (non-public)).

84 Id. at 10.

85 Id. at 8.

86 LBP-17-7, 86 NRC at 114.

87 Id. at 121.

88 Tier 2 structures are those areas with 0.5 millimeters per meter (mm/m) (0.05%) to 1.0 mm/m (0.1%) of in-plane expansion and are monitored every 30 months. See Ex. INT010, Original LAR at PDF 65.

89 Tier 3 structures are areas with in-plane expansion measured at 1.0 mm/m (0.1%) or more.

These areas are scheduled for inspection every 6 months. See id.

90 C-10 Petition at 15.

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Official Use Only Proprietary Information whether ASR progresses at a steady rate or at an accelerating (or decelerating) rate and therefore the SMPs monitoring intervals were not appropriately conservative. 91 Under 10 C.F.R. §§ 2.319(j) and 2.329(c)(1) and pursuant to Commission precedent, 92 the Board combined Contention D with portions of Contentions A, B, C, and H that each alleged defects in the LARs monitoring program, acceptance criteria, and inspection intervals. 93 We concluded that [b]ecause of the interrelated nature of the five admissible contentions, consolidation will promote a more efficient proceeding. 94 We therefore reformulated the admissible portions of Contentions A, B, C, D, and H into a single admitted 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. 95 On October 31, 2017, NextEra appealed our admission of the reformulated contention, arguing the Board should have denied C-10s hearing request. 96 Both C-10 and the Staff opposed the appeal. 97 NextEra challenged the Boards determination regarding the consolidation of the five contentions which the Board found admissible and, finally, the admissibility of the single, reformulated contention. 98 91 Id.

92 See supra note 4.

93 LBP-17-7, 86 NRC at 127.

94 Id. at 90.

95 Id.

96 NextEras Notice of Appeal of LBP-17-7 (Oct. 31, 2017); Brief in Support of NextEras Appeal of LBP-17-7 (Oct. 31, 2017) [hereinafter NextEras Appeal of LBP-17-7].

97 [C-10] Response to NextEras Appeal of LBP-17-7: Whereby the Atomic Safety and Licensing Board Granted Standing to [C-10] to Intervene in Docket No. 50-443-LA-2 and Admitted Five of Its Contentions (Nov. 22, 2017); NRC Staff Brief in Opposition to NextEras Appeal of LBP-17-7 (Nov. 27, 2017).

98 NextEras Appeal of LBP-17-7 at 13-30.

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Official Use Only Proprietary Information The Commission affirmed the Boards decision in LBP-17-7 and found that NextEra had not demonstrated an error of law or abuse of discretion concerning the Boards decision to admit the reformulated contention. 99 C. C-10s Emergency Motion On February 13, 2019, C-10 filed an emergency petition that requested the Commission exercise its supervisory authority and reverse the Staffs no significant hazards consideration determination (NSHCD) and immediately suspend the license amendment and as well as suspend a separate, related decision to renew the Seabrook operating license. 100 Moreover, C-10 requested that the Commission take other appropriate actions in this proceeding to ensure adequate consideration and resolution of the seismic risk implications of ongoing and increasing

[ASR]-related degradation in the Seabrook containment and other concrete safety structures. 101 C-10 argued the Commission should review and reverse the Staffs NSHCD until after the adjudicatory hearing. 102 Further, C-10 asked the Commission to investigate best practices for ASR and provide guidance to the Staff for evaluating ASR-related safety risks. 103 Both NextEra and the Staff opposed the petition. 104 On July 25, 2019, the Commission declined to grant C-10s requested relief. 105 The Commission first noted that the petition was procedurally improper since Commission 99 CLI-18-4, 87 NRC at 110.

100 Emergency Petition by [C-10] for Exercise of Commissions Supervisory Authority to Reverse No Significant Hazards Determination and Immediately Suspend License Amendment and License Renewal Decisions (Feb. 13, 2019) [hereinafter Emergency Petition].

101 Id. at 1-2.

102 Id. at 3.

103 Id. at 4, 16.

104 NextEras Ans. Opposing C-10s Emergency Petition (Feb. 25, 2019); NRC Staffs Ans. to C-10s Emergency Petition (Feb. 25, 2019).

105 See CLI-19-7, 90 NRC 1, 2 (2019).

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Official Use Only Proprietary Information regulations explicitly contemplate the issuance of an amendment to a reactor license during the pendency of a hearing on the amendment, as long as the NRC has first determined that the amendment involves no significant hazards consideration. 106 The Commission emphasized the distinction between a decision on the license amendment request, which requires reasonable assurance of adequate protection of the health and safety of the public and the common defense and security, and a NSHCD, which only addresses whether a hearing must be held before or after issuance of an amendment. 107 Further, the Commission reasoned that 10 C.F.R.

§§ 50.58(b)(6) and 2.1213(f) bar C-10 from requesting a delay of the issuance of the license amendment by the Commission until the Commission reviews the Staffs NSHCD. 108 Accordingly, the Commission declined the request to stay the effectiveness of the renewed license 109 and found no compelling reason to exercise its discretionary authority to immediately suspend the license amendment, finding C-10s emergency petition lacked legitimate urgency. 110 The Commission observed that C-10 failed to address the possibility that the license amendment could be altered to provide effective redress upon conclusion of the evidentiary hearing. 111 The Commission noted as well that the Board has the authority to revoke or place conditions on the license amendment if it determines the Staff should not have granted it. 112 106 Id. at 8 (citing Atomic Energy Act of 1954 § 189a(2)(A), 42 U.S.C. § 2239(a)(2)(A); 10 C.F.R.

§§ 50.91(a)(4), 50.92).

107 Id.; see Final Procedures and Standards on No Significant Hazards Considerations; Final Rule, 51 Fed. Reg. 7744, 7749 (Mar. 6, 1986); see also 10 C.F.R. §§ 50.40, 50.92.

108 CLI-19-7, 90 NRC at 8-9.

109 Id. at 10.

110 See id. at 10, 12.

111 Id. at 10-11.

112 Id. at 11 (citing Entergy Nuclear Vt. Yankee, LLC (Vermont Yankee Nuclear Power Station),

CLI-06-8, 63 NRC 235, 238 (2006)).

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Official Use Only Proprietary Information D. Plant Tour Before the evidentiary hearing, the Board determined that it would benefit from a plant tour of Seabrook. The Boards goals for the tour included (1) developing site familiarity and an understanding of the affected concrete structures at the plant; (2) viewing various ASR-affected areas; and (3) observing the Cracking Index (CI) and CCI methodologies as applied to typical ASR-monitoring. 113 The Board explained that the purpose of the tour was solely to enable the Board to better understand the evidence that the parties may submit during the evidentiary hearing for this proceeding. 114 Therefore, to the extent any party wanted the evidentiary record to reflect any matter observed or discussed during the tour, that party had to make an appropriate evidentiary submission to the Board that reflected such matters. 115 On June 21, 2019, the Board, together with representatives from the Staff, NextEra, and C-10, viewed various core-sampling, monitoring, and extensometer locations at Seabrook.

These included the Exterior Diesel Generator Building CCI panel and extensometer; the Exterior Fuel Storage Building (FSB) CCI panels and extensometers; the Exterior Containment Enclosure Building (CEB)/Equipment Hatch Missile Shield CCI panels; the Condensate Storage Tank Enclosure exterior CCI panels and extensometers; and the B Electrical Tunnel. 116 Subsequently, the Board and the other participants viewed additional CCI panels, extensometers, and coring locations placed in various areas and observed an extensometer model and a core sampling display.

113 See Licensing Board Memorandum (Concerning Plant Tour) (Apr. 29, 2019) at 2 (unpublished).

114 See Licensing Board Memorandum (Confirming Plant Tour) (May 29, 2019) at 1 (unpublished).

115 Id. at 1-2.

116 See Joint Proposal Regarding Plant Tour (May 9, 2019) at 2.

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Official Use Only Proprietary Information E. Evidentiary Hearing From September 24-27, 2019, the Board held an evidentiary hearing in Newburyport, Massachusetts, at the Newburyport City Hall Auditorium. 117 At the hearing, the Board received statements from counsel, heard testimony from witnesses for the Staff, NextEra, and C-10, and admitted party exhibits into the evidentiary record. 118 Subsequently, in an October 29, 2019 issuance, the Board adopted corrections to the hearing transcripts, 119 adopted redactions to the transcript of the closed hearing sessions conducted on Wednesday, September 25, 2019, and Friday, September 27, 2019, so as to allow for a publicly available version of those hearing sessions, and adopted the final exhibit list. 120 On November 21, 2019, the Staff, NextEra, and C-10 submitted proposed findings of fact and conclusions of law. 121 Thereafter, the parties sought a time extension to submit responsive proposed findings. 122 On December 2, 2019, the Board granted the requested extension. 123 NextEra filed its Responsive Proposed Findings of Fact and Conclusions of Law 117 See Tr. at 214-1203.

118 See Licensing Board Order (Adopting Transcript Corrections, Transcript Redactions, and Final Exhibit List) (Oct. 29, 2019) (unpublished).

119 See id. at 2.

120 Id.

121 [NextEra]s Proposed Findings of Fact and Conclusions of Law (Nov. 21, 2019) [hereinafter NextEras Proposed Findings of Fact and Conclusions of Law]; NRC Staff Proposed Findings of Fact and Conclusions of Law for the Admitted Contention (Nov. 21, 2019) [hereinafter NRC Staffs Proposed Findings of Fact and Conclusions of Law]; [C-10]s Proposed Findings of Fact and Conclusions of Law (Nov. 21, 2019). C-10 later submitted an Errata to its initial Proposed Findings of Fact and Conclusions of Law. C-10s Errata to Proposed Findings of Fact and Conclusions of Law (Nov. 27, 2019); see [Corrected] [C-10]s Proposed Findings of Fact and Conclusions of Law (Nov. 27, 2019); see also [Redacted] [Corrected] [C-10]s Proposed Findings of Fact and Conclusions of Law (Feb. 12, 2020).

122 See Unopposed Motion for Extension of Time to Seek Leave to File Responsive Proposed Findings of Fact and Conclusions of Law (Nov. 29, 2019). At the evidentiary hearing, the Board instructed that the parties would need to seek leave to submit any responsive proposed findings. See Tr. at 1181 (Spritzer).

123 Licensing Board Order (Granting Time Extension to File Motions for Leave to Submit Responsive Proposed Findings of Fact and Conclusions of Law) (Dec. 2, 2019) at 1 Official Use Only Proprietary Information

Official Use Only Proprietary Information on December 13, 2019, 124 and then filed a corrected version on December 17, 2019. 125 Subsequently, C-10 moved for leave to submit a response to NextEras Responsive Proposed Findings of Fact and Conclusions of Law. 126 The Board denied the motion because such an additional round of filings would go well beyond the submissions authorized under 10 C.F.R. § 2.1209 and would unnecessarily add to the several hundred pages of proposed findings of fact and conclusions of law already before the Board. 127 F. Motion to Compel Mineralogical Data During the evidentiary hearing, a dispute arose as to whether NextEra should produce a document that compared the mineralogy of the Seabrook aggregate and the LSTP test specimen aggregate. 128 On September 30, 2019, C-10 moved to compel NextEra to produce a document or documents containing data regarding the tested mineralogical components of aggregate in Seabrook concrete. 129 C-10 maintained that the production of the Seabrook aggregate data was necessary to make a complete record for the resolution of the dispute (unpublished). The Board tasked the parties with filing any motion seeking leave to file responsive proposed findings of fact and conclusions of law on or before Friday, December 13, 2019. Id. at 2. Additionally, the Board ordered that any motion be accompanied by the responsive proposed findings of fact and conclusions of law. Id.

124 [NextEra]s Motion for Leave to File Responsive Proposed Findings of Fact and Conclusions of Law (Dec. 13, 2019).

125 [NextEra]s Corrected Responsive Proposed Findings of Fact and Conclusions of Law (Dec.

17, 2019); see also [NextEra]s Errata to Responsive Proposed Findings of Fact and Conclusions of Law (Dec. 17, 2019).

126 [C-10]s Response to NextEras Motion for Leave to File Responsive Proposed Findings of Fact and Conclusions of Law (Dec. 18, 2019).

127 Licensing Board Order (Granting NextEras Motion for Leave to File Responsive Proposed Findings of Fact and Conclusions of Law) (Jan. 6, 2020) at 2 (unpublished).

128 Tr. at 1080-81.

129 [C-10]s Motion to Compel Production of Mineralogy Data and Request for Opportunity to Submit Supplemental Written Testimony Regarding the Data (Sept. 30, 2019) at 1 [hereinafter Motion to Compel].

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Official Use Only Proprietary Information between the parties regarding the representativeness of the [LSTP test data]. 130 C-10 also requested a reasonable opportunity for Dr. [Victor E.] Saouma[, C-10s expert] to give a written expert opinion on the comparability of the Seabrook aggregate with the LSTP test specimen aggregate. 131 NextEra opposed the motion; the Staff did not file a response. 132 NextEra argued, among other things, that it already produced documents containing mineralogical data as part of its initial disclosures in January 2018. 133 In response, the Board issued a Request for Clarification from C-10, inquiring whether the disclosed documents contained the mineralogical data sought. 134 C-10 submitted a reply stating that NextEras initial disclosures did not include the requested mineralogical data, and also requesting leave to file two additional exhibits. 135 Both NextEra and the Staff opposed the Motion to Submit Additional Exhibits. 136 On November 25, 2019, the Board granted C-10s Motion to Compel but denied its Motion to Submit Additional Exhibits. 137 The Board established a schedule that required NextEra to produce all documents within its possession, custody, or control not previously produced containing data regarding the 130 Id.

131 Id. at 4.

132 NextEras Ans. Opposing C-10s Motions to Compel Production of Mineralogical Data and to Submit Additional Post-Hearing Testimony (Oct. 9, 2019).

133 Id. at 3-4.

134 Licensing Board Memorandum (Request for Clarification) (Oct. 16, 2019) at 2 (unpublished).

135 [C-10]s Response to ASLB Memorandum and Motion to Submit Additional Exhibits Regarding Petrographic Observations and Analyses of ASR at Seabrook (Oct. 28, 2019) at 2, 3-4.

136 NextEras Ans. Opposing C-10s Third Motion for Leave to File Supplemental Testimony (Nov. 6, 2019); NRC Staffs Ans. Opposing C-10s Motion to Admit Additional Exhibit and Testimony (Nov. 6, 2019).

137 Licensing Board Order (Granting C-10s Motion to Compel Mineralogical Data and Request to Submit Supplemental Written Testimony Concerning the Data; Denying C-10s Motion to Submit Additional Exhibits) (Nov. 25, 2019) at 4 (unpublished).

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Official Use Only Proprietary Information tested mineralogical components of aggregate in Seabrook concrete. 138 Additionally, the Board provided an opportunity for Dr. Saouma to file written testimony explaining how the newly produced data affects his evaluation of the comparability of the Seabrook aggregate and the LSTP test specimen aggregate. 139 Finally, the Board allowed both NextEra and the Staff to file written rebuttal testimony in response to Dr. Saoumas new written testimony. 140 On December 5, 2019, NextEra produced one document in response to the Board order granting the Motion to Compel. 141 The document, titled Santa Ana Aggregates, 142 contained an examination of aggregate samples from a New Mexico quarry (which was not used in Seabrooks concrete), along with a comparison of that aggregate to Seabrooks aggregate. 143 As permitted by the Board, C-10 filed Dr. Saoumas written explanation regarding that document. 144 Both NextEra and Staff submitted exhibits in response. 145 138 Id. at 17.

139 Id.

140 Id.

141 Letter from Paul M. Bessette, NextEra, to Diane Curran, C-10 (Dec. 5, 2019) (ADAMS Accession No. ML19339H135) [hereinafter NextEra Motion to Compel Letter].

142 See id. attach. Santa Ana Aggregates Petrography Report (Jan. 8, 2013) (ADAMS Accession No. ML19339H136) [hereinafter Santa Ana Aggregates Report].

143 NextEra Motion to Compel Letter at 1 (emphasis omitted).

144 Ex. INT051-R, Supplemental Testimony of Victor E. Saouma, Ph. D Regarding Adequacy of Petrographic Documents to Support Mineralogical Comparison Between Seabrook Concrete and LSTP Test Specimens [hereinafter Ex. INT051-R, Dr. Saouma Supp. Testimony]. The Board admitted Ex. INT051-R on January 17, 2020. See Licensing Board Order (Admitting Exhibits, Closing the Record of the September 2019 Evidentiary Hearing, and Providing Additional Instruction for Supplemental Proposed Findings) (Jan. 17, 2020) at 1 (unpublished)

[hereinafter Order Closing the Hearing Record].

145 See Ex. NER077, Testimony of NextEra Witnesses John Simons, Christopher Bagley, Oguzhan Bayrak, Matthew Sherman, and Edward Carley in Response to Exhibit INT051-R

[hereinafter Ex. NER077, NextEra Response to Ex. INT051-R]; see also Ex. NRC091, Staff Testimony in Response to Exhibit INT051-R [hereinafter Ex. NRC091, Staff Response to Ex.

INT051-R]. The Board admitted both exhibits on January 17, 2020. See Order Closing the Hearing Record at 1.

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Official Use Only Proprietary Information Following the submission of the additional exhibits related to the mineralogical data, the Board closed the evidentiary record. 146 On January 31, 2020, the parties filed supplemental proposed findings of fact and conclusions of law, limited to the specific issues raised in Dr.

Saoumas new testimony and the rebuttal testimony submitted by NextEra and the Staff. 147 III. Legal Standards A. Regulatory Framework

1. Seismic Category I Structures Some Seabrook structures, systems, and components (SSCs), including their foundations and supports, are designated as seismic Category I structures 148 because they are designed to withstand the effects of an Operating Basis Earthquake (OBE) 149 and a Safe Shutdown Earthquake (SSE). 150 Seismic Category I SSCs are those necessary to ensure: (1) 146 See Order Closing the Hearing Record at 2.

147 [NextEra]s Supplemental Proposed Findings of Fact and Conclusions of Law (Jan. 31, 2020); NRC Staff Supplemental Proposed Findings of Fact and Conclusions of Law (Jan. 31, 2020) [hereinafter NRC Staffs Supp. Proposed Findings of Fact and Conclusions of Law]; [C-10]s Supplemental Proposed Findings of Fact and Conclusions of Law (Jan. 31, 2020). C-10 later submitted a redacted version of its Supplemental Proposed Findings of Fact and Conclusions of Law. See Redacted [C-10]s Supplemental Proposed Findings of Fact and Conclusions of Law (Feb. 12, 2020) [hereinafter C-10s Redacted Supp. Proposed Findings of Fact and Conclusions of Law].

148 Equipment and components that are not classified as seismic Category I, and whose collapse or failure could result in the loss of safety function of a seismic Category I [SSC], are checked to confirm their structural integrity against collapse or failure due to SSE loadings. Ex.

NRC007, Seabrook Station Updated Final Safety Analysis Report, Chapter 3, Design of Structures, Components, Equipment and Systems § 3.2.1 (Oct. 2017) [hereinafter Ex. NRC007, UFSAR]; see supra note 2.

149 OBE is the vibratory ground motion for which those features of the nuclear power plant necessary for continued operation without undue risk to the health and safety of the public will remain functional. SSE is the maximum earthquake potential for which certain structures, systems, and components, important to safety, are designed to sustain and remain functional.

The OBE response spectra are obtained by multiplying the SSE response spectra by one-half.

Ex. NRC007, UFSAR §§ 3.7(B).1.1, 3.7(N).

150 Appendix S to 10 C.F.R. Part 50, Earthquake Engineering Criteria for Nuclear Power Plants, requires that all nuclear power plants be designed so that certain SSCs remain functional if the SSE ground motion occurs. 10 C.F.R. pt. 50, app. S.

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Official Use Only Proprietary Information the integrity of the reactor coolant pressure boundary; (2) the capability to shut down the reactor and maintain it in a safe shutdown condition; [and] (3) the ability to prevent or mitigate the consequences of accidents that could result in potential offsite exposures comparable to the guideline exposures 151 required by 10 C.F.R. §§ 50.34(a)(1) and 100.11. The pertinent quality assurance requirements of Appendix B to 10 C.F.R. Part 50 apply to all activities that affect the safety-related functions of seismic Category I SSCs at Seabrook. 152 Appendix S to 10 C.F.R.

Part 50 requires that the design for all nuclear power plants allow for certain SSCs to remain functional if SSE ground motion occurs. 153 These structures are sufficiently isolated and protected from non-seismic Category I structures to safeguard their integrity from design basis events. 154

2. Updated Final Safety Analysis Report, Section 3.8 The UFSAR contains design and licensing basis information for a nuclear power facility, including how the facility meets the regulatory requirements for the design and how the facility responds to various design basis accidents and events. Analytical methods of evaluation are a fundamental part of demonstrating how the design meets regulatory requirements and why the facilitys response to accidents and incidents is acceptable. In cases where the analytical methodology is an essential part of the conclusion that the facility meets the required design bases, the UFSAR must describe the specific analytical methods, which are then subject to varying levels of NRC review and approval during licensing. 155 151 10 C.F.R. pt. 50, app. S. § III.

152 See Ex. NRC088, RG 1.29 at 2.

153 See 10 C.F.R. pt. 50, app. S.

154 Ex. NRC007, UFSAR § 3.2.1.

155 See 10 C.F.R. § 50.71(e).

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Official Use Only Proprietary Information Chapter 3 of the Seabrook UFSAR identifies, describes, and discusses the principal architectural and engineering design of those SSCs important to safety. 156 UFSAR section 3.8 includes the requirements for the design of seismic Category I structures at Seabrook. 157 Section 3.8.1 applies to the concrete containment building, and section 3.8.4 applies to other seismic Category I structures. 158 The LAR modified each of these subsections to incorporate the changes related to ASR material effects and loads. Additional LAR-proposed changes to other subsections of the UFSAR were necessary for limits on anchors in concrete walls and slabs affected by ASR, and to allow the use of ANSYS 159 computer software. 160 10 C.F.R. § 50.59 sets forth the circumstances under which a licensee may make changes to its facility as described in its UFSAR, 161 make changes in the procedures described in the UFSAR, and conduct tests or experiments not otherwise specified in the UFSAR. The licensee may take such action without obtaining a license amendment if there is no change to 156 Ex. NRC007, UFSAR § 3.

157 Id. § 3.8.

158 Id. §§ 3.8.1, 3.8.4.

159 ANSYS, Inc. is a software company that develops engineering simulations. NextEra used a model developed by ANSYS in simulating the effects of ASR on Seabrook concrete. See Ex.

INT010, Original LAR at PDF 26, 30.

160 The proposed changes to the specific subsections of the Seabrook UFSAR are described in Ex. INT011 and the UFSAR markup pages are provided in Attachment 1 to that exhibit. Ex.

INT011, NextEra Energys Evaluation of the Proposed Change Including Attachment 1 Markup of UFSAR Pages (Enclosure 1 to Letter SBK-L-16071) at PDF 40-70 [hereinafter Ex. INT011, Evaluation of the Proposed Change] (non-public). Ex. INT011, Evaluation of the Proposed Change, is a 70-page PDF with unnumbered pages. For reference clarity, this Board will refer to all pages with their PDF page numbers.

161 Of particular importance to Seabrook, 10 C.F.R. § 50.59(c)(2)(viii) requires a licensee to obtain a license amendment pursuant to 10 C.F.R. § 50.90 before implementing a proposed change if the change would result in a departure from a method of evaluation described in the FSAR (as updated) used in establishing the design bases or in the safety analyses. See Ex.

INT010, Original LAR at PDF 35. This is just the type of change involved in the UFSAR revisions at issue in this proceeding.

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Official Use Only Proprietary Information the facilitys technical specifications 162 and the licensing action does not fall into one of eight specific categories. 163 Under certain circumstances, however, a licensee must apply for a license amendment and obtain NRCs approval before it can implement any such proposed change. 164

3. License Amendments Under 10 C.F.R. § 50.90, whenever a licensee seeks to amend its license, including technical specifications in the license, it must file an application for amendment that fully describes the changes desired. In determining whether an amendment to a license, construction permit, or early site permit will be issued to the applicant, the Commission will be guided by the considerations which govern the issuance of initial licenses, construction permits, or early site permits to the extent applicable and appropriate. 165 Accordingly, pursuant to 10 C.F.R. § 50.57(a)(3) and (a)(6), a license amendment must provide:

(3) . . . [R]easonable assurance (i) that the activities authorized by the operating license can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the regulations in this chapter; and . . . [that]

(6) The issuance of the license will not be inimical to the common defense and security or to the health and safety of the public. 166 Similarly, 10 C.F.R. § 50.40, entitled Common standards, requires that the Commission be persuaded, inter alia, that the applicant will comply with all applicable 162 See 10 C.F.R. § 50.59(c)(1).

163 See id. § 50.59(c)(2).

164 See id. §§ 50.59(c)(2), 50.90.

165 See id. § 50.92(a).

166 See id. § 50.57(a)(3), (6); see Gen. Pub. Utils. Nuclear Corp. (Three Mile Island Nuclear Station, Unit 2), LBP-89-7, 29 NRC 138, 190-91 (1989); see also Duke Power Co. (Catawba Nuclear Station, Units 1 & 2), LBP-82-116, 16 NRC 1937, 1946 (1982) (citing Va. Elec. & Power Co. (N. Anna Nuclear Power Station, Units 1 & 2), ALAB-491, 8 NRC 245 (1978)).

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Official Use Only Proprietary Information regulations, that the health and safety of the public will not be endangered, [and] that the issuance of the amendment will not be inimical to the health and safety of the public . . . . 167 Pursuant to the Atomic Energy Act, applicants seeking license amendments must demonstrate that the amended license provide[s] adequate protection to the health and safety of the public. 168 Specifically, the Commission requires that 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. 169 Although the Commission has not defined adequate protection, the phrase is synonymous with no undue risk. 170 In this proceeding, we are concerned with the effects of ASR on Seabrooks safety-related structures and structural components. NextEra must demonstrate with reasonable assurance that structures or components in the LAR will remain capable of fulfilling their intended functions under design basis loads and load combinations. 171 The Commission stated 167 10 C.F.R. § 50.40; see N. States Power Co. (Prairie Island Nuclear Generation Plant, Units 1

& 2), ALAB-455, 7 NRC 41, 44 (1978); accord Tenn. Valley Auth. (Browns Ferry Nuclear Plant, Units 1, 2, & 3), ALAB-664, 15 NRC 1, 15-16 (Prior to license issuance the NRC must first find reasonable assurance that the activities authorized by the amendment can be conducted without endangering the health and safety of the public, and in compliance with Commission regulations.), vacated and remanded on other grounds, CLI-82-26, 16 NRC 880 (1982); Fla.

Power & Light Co. (Turkey Point Nuclear Generating Station, Units 3 & 4), LBP-81-16, 13 NRC 1115, 1120 (1981) (reviewing a proposed license amendment to determine whether it would endanger the health and safety of the public).

168 Atomic Energy Act § 182, 42 U.S.C. § 2232; see Union of Concerned Scientists v. NRC, 824 F.2d 108, 118 (D.C. Cir. 1987) (holding the NRC need not demand that nuclear power plants present no risk of harm to satisfy the adequate protection standard); Carstens v. NRC, 742 F.2d 1546, 1557 (D.C. Cir. 1984); CLI-19-7, 90 NRC at 8; CLI-18-4, 87 NRC at 110; Palisades, CLI-15-22, 82 NRC at 316; DTE Elec. Co. (Fermi Nuclear Power Plant, Unit 3), CLI-15-4, 81 NRC 221, 231 n.49 (2015).

169 Palisades, CLI-15-22, 82 NRC at 316.

170 See Union of Concerned Scientists, 824 F.2d at 119.

171 10 C.F.R. §§ 50.40(a), 50.57(a)(3)(i)-(ii).

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Official Use Only Proprietary Information that the [r]easonable assurance [standard] 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. 172 In general, the Commission undertakes a case-by-case approach in making a reasonable assurance determination, considering all relevant facts and circumstances to reach a sound technical judgment that verifies an applicants compliance with all applicable regulations. 173 To date, however, no specific NRC guidance, regulatory standard, or nuclear industry guidance exists to address the effects of ASR on nuclear power plants. 174 Moreover, neither of the building codes applicable to Seabrooks safety-related structures contain methods to address the effects of ASR on the structural properties of seismic Category I structures. 175 Therefore, the Board must evaluate all the evidence within the scope of the reformulated contention, relying in large part on the testimony of qualified experts and the exhibits on which they rely to determine whether the reasonable assurance standard has been met.

In addition to satisfying the reasonable assurance standard, a licensee must comply with the applicable NRC General Design Criteria (GDC) for Nuclear Power Plants, specified in 10 172 AmerGen Energy Co., LLC (Oyster Creek Nuclear Generating Station), CLI-09-7, 69 NRC 235, 262-63 (2009); see AmerGen Energy Co., LLC (Oyster Creek Nuclear Generating Station), LBP-07-17, 66 NRC 327, 340 (2007), affd CLI-09-7, 69 NRC 235 (2009) (stating the reasonable assurance standard is not susceptible to formalistic quantification (i.e., 95%

confidence) or mechanistic application); see also N. Anna Envtl. Coal. v. NRC, 533 F.2d 655, 667-68 (D.C. Cir. 1976) (rejecting the argument that reasonable assurance requires proof beyond a reasonable doubt and noting that the licensing board equated reasonable assurance with a clear preponderance of the evidence).

173 Oyster Creek, CLI-09-7, 69 NRC at 262 n.143; Entergy Nuclear Generation Co. (Pilgrim Nuclear Power Station), CLI-10-14, 71 NRC 449, 465-66 (2010).

174 See Improved Identification Techniques Against Alkali-Silica Reaction (ASR) Concrete Degradation at Nuclear Power Plants, 84 Fed. Reg. 65023, 65023 (Nov. 26, 2019) (NRC denial of petition for rulemaking to set ASR standards).

175 See Ex. INT010, Original LAR at PDF 11.

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Official Use Only Proprietary Information C.F.R. Part 50, Appendix A. 176 Here, the relevant GDCs are GDC 1 (Quality Standards and Records), 177 GDC 2 (Design Bases for Protection Against Natural Phenomena), 178 GDC 4 (Environmental and Missile Design Bases), 179 GDC 16 (Containment Design), 180 and GDC 50 (Containment Design Basis). 181 GDC 1, 2, and 4 apply to Seabrook seismic Category I structures, whereas GDC 16 and 50 apply only to containment structures.

GDC 1 requires that structures, systems, and components [SSCs] important to safety shall be designed, fabricated, erected, and tested to quality standards commensurate with the importance of the safety functions to be performed. 182 In addition, GDC 1 states [w]here generally recognized codes and standards are used, they shall be identified and evaluated to determine their applicability, adequacy, and sufficiency and shall be supplemented or modified as necessary to assure a quality product in keeping with the required safety function. 183 GDC 1 also requires the implementation of a quality assurance program to assure that these [SSCs]

will satisfactorily perform their safety functions . . . . 184 GDC 2 requires all SSCs to be designed to withstand the effects of natural phenomena such as earthquakes, tornadoes, hurricanes, floods, tsunami, and seiches without loss of capability to perform their safety functions, 185 whereas GDC 4 requires all SSCs to be designed to accommodate the effects of and to be compatible with the environmental conditions associated with normal operation, 176 Each GDC is discussed in detail in the UFSAR. See Ex. NRC007, UFSAR § 3.1.

177 Id. § 3.1.1.1.

178 Id. § 3.1.1.2.

179 Id. § 3.1.1.4.

180 Id. § 3.1.2.7.

181 Id. § 3.1.5.1.

182 10 C.F.R. pt. 50, app. A.

183 Id. (emphasis added).

184 Id.

185 Id.

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Official Use Only Proprietary Information maintenance, testing, and postulated accidents, including loss-of-coolant accidents [and] . . . be appropriately protected against dynamic effects, including the effects of missiles, pipe whipping, and discharging fluids . . . . 186 GDC 16 and 50, which apply to containment structures, such as those at Seabrook, require those structures to maintain a leak-tight barrier against the uncontrolled release of radioactivity to the environment and to assure that the containment design conditions important to safety are not exceeded, 187 and mandate that the internal components of the containment structure can accommodate . . . the calculated pressure and temperature conditions resulting from any loss-of-coolant accident . . . . 188 Further, 10 C.F.R. Part 50, Appendix B provides quality assurance requirements for the design, manufacture, construction, and operation of SSCs that prevent or mitigate the consequences of postulated accidents that could cause undue risk to the health and safety of the public. 189 Section Ill of Appendix B to 10 C.F.R. Part 50, Design Control, requires that the applicable regulatory requirements and 10 C.F.R. § 50.2 defined design basis for those SSCs covered by Appendix B be correctly translated into specifications, drawings, procedures, and instructions. 190 186 Id.

187 Id.

188 Id.

189 See 10 C.F.R. pt. 50, app. B.

190 Id. § III.

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Official Use Only Proprietary Information B. Legal Standards Governing this Proceeding

1. Burden of Proof An Intervenor has the initial burden of going forward, 191 which requires an intervenor to establish a prima facie case 192 for claims asserted in the reformulated contention. The admission of a contention, by itself, does not satisfy the burden of going forward. 193 An intervenor must provid[e] probative evidence or expert testimony. 194 The applicant bears the burden of proof for all matters on which an intervenor has satisfied its burden of going forward, requiring the applicant to show by a preponderance of the evidence that it is entitled to the applied-for license. 195 Thus, NextEra must show by a preponderance of the evidence that [t]here is reasonable assurance . . . that the activities authorized by the operating license can be conducted without endangering the health and safety of the public, and that all applicable regulations (which in this case would include GDC 1, 2, 4, 16, 50 and Appendix B to 10 C.F.R. Part 50) are satisfied. 196 For safety-related matters, there is 191 Oyster Creek, CLI-09-7, 69 NRC at 269 (quoting Consumers Power Co. (Midland Plant, Units 1 & 2), ALAB-123, 6 AEC 331, 345 (1973) (The ultimate burden of proof on the question of whether the permit or license should be issued is . . . upon the applicant. But where . . . one of the other parties contends that, for a specific reason . . . the permit or license should be denied, that party has the burden of going forward with evidence to buttress that contention.

Once he has introduced sufficient evidence to establish a prima facie case, the burden then shifts to the applicant who, as part of his overall burden of proof, must provide a sufficient rebuttal to satisfy the Board that it should reject the contention as a basis for denial of the permit or license.)).

192 Pac. Gas & Elec. Co. (Diablo Canyon Nuclear Power Plant, Units 1 & 2), ALAB-653, 16 NRC 55, 72 (1981) (Prima facie evidence must be legally sufficient to establish a fact or case unless disproved.).

193 See Oyster Creek, CLI-09-7, 69 NRC at 268-70.

194 Id. at 269.

195 See 10 C.F.R. § 2.325; N. Anna Envtl. Coal., 533 F.2d at 667-68.

196 10 C.F.R. § 50.57(a)(3)(i)-(ii); see also id. § 50.40(a); Pac. Gas & Elec. Co. (Diablo Canyon Nuclear Power Plant, Units 1 & 2), ALAB-763, 19 NRC 571, 577-78 (1984); Oyster Creek, CLI-09-7, 69 NRC at 263.

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Official Use Only Proprietary Information no burden on the Staff, but a Board will consider the Staffs safety evaluation in reaching its determination. 197 In sum, NextEra carries the burden of proof on the issue whether there is reasonable assurance that the operation of Seabrook, as modified by the LAR, will not endanger the health and safety of the public. 198 In making a case-by-case determination of reasonable assurance, a licensing board must weigh the expert testimony and give an expert due weight proportionate to his/her expertise. 199 Any gaps in an experts knowledge go to the weight of the testimony. 200 General expertise on a matter may be useful, even if there are knowledge gaps in specific areas. 201 A board may reject an experts assertions, however, if they are based on no more than a gut feeling and the expert acknowledges that he ha[d not] analyzed relevant documentation. 202 If expert testimony is crucial to the outcome of a safety or environmental issue, the expert must make available . . . sufficient information pertaining to the details of the analysis to permit the 197 Private Fuel Storage, L.L.C. (Independent Spent Fuel Storage Installation), LBP-03-4, 57 NRC 69, 140-41 (2003) ([U]nder the Commissions time-tested licensing and hearing processes, the Staffs evaluation of an applicants proposal reached as it conducts its independent evaluation of an applicants proposal is considered an integral part of the record that is developed regarding any contentions challenging what an applicant has put forward.

Even though the Staffs position may not prevail at trial, it is presumed that the development and exploration of a contested issue will benefit from the Staffs analysis and presentation.). The Staff is required to submit certain documents into evidence. See 10 C.F.R. § 2.337(g).

198 See Consumers Power Co. (Midland Plant, Units 1 & 2), ALAB-283, 2 NRC 11, 17 (1975).

199 Carolina Power & Light Co. (Shearon Harris Nuclear Power Plant), LBP-01-9, 53 NRC 239, 250 (2001).

200 Duke Energy Corp. (Catawba Nuclear Station, Units 1 & 2), CLI-04-21, 60 NRC 21, 29 (2004).

201 Id. at 31 (Unwarranted and inflexible barriers, such as too great an insistence on specific knowledge in selected aspects of the subject, should not disqualify an expert witness who possesses a strong general background and specialized knowledge in the relevant field.).

202 See Entergy Nuclear Operations, Inc. (Indian Point, Units 2 & 3), LBP-13-13, 78 NRC 246, 301 (2013).

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Official Use Only Proprietary Information correctness of the conclusion to be evaluated. 203 In other words, an expert must make available data used in analyses to support conclusions asserted in the experts testimony to enable a licensing board to make a reasoned judgment on the weight. 204 IV. Seabrook License Amendment A. NRC Staff Safety Evaluation The Staff issued a draft Safety Evaluation (SE) for the LAR on September 28, 2018 and provided it to the Advisory Committee on Reactor Safeguards (ACRS) that same day. 205 Based on its review of the LAR and that Staff report, the ACRS concluded that NextEra ha[d]

undertaken substantial and thorough actions to identify, understand, and address [ASR]. 206 In addition, the ACRS found that [t]he LSTP test samples were highly representative of the ASR-affected structures at Seabrook. 207 The ACRS did not provide any recommendations for modifying the proposed ASR monitoring programs in the LAR. 208 203 Va. Elec. & Power Co. (N. Anna Nuclear Power Station, Units 1 & 2), ALAB-555, 10 NRC 23, 27 (1979) (It is not unreasonable, however, to insist that where, as here, the outcome on a clearly defined and substantial safety or environmental issue may hinge upon the acceptance or rejection of an expert conclusion resting in turn upon a performed analysis, the witness make available (either in his prepared testimony or on the stand) sufficient information pertaining to the details of the analysis to permit the correctness of the conclusion to be evaluated.).

204 See id. at 26.

205 Ex. NRC047, Memorandum from James G. Danna, NRC, to Andrea D. Veil, NRC 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 (CAC No. MF8260; EPID L-2016-LLA-0007) (Sept. 28, 2018). Created by the AEA, the ACRS, among other duties, reviews and reports on safety studies and applications for construction permits and facility operating licenses[.] 10 C.F.R. § 1.13.

206 Ex. NRC048, 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 (Dec. 14, 2018) at 1.

207 Id. at 3.

208 Id. at 2-4.

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Official Use Only Proprietary Information Thereafter, on March 11, 2019, the Staff issued a final SE to accompany the requested Seabrook operating license amendment, denominated as License Amendment No. 159. 209 In the final SE, the Staff concluded that NextEra had developed a representative test program and that it [was] reasonable to apply the conclusions of the [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. 210 The Staff, however, noting that this [was] a first-of-a-kind approach, imposed a license condition with two components that require[s] [NextEra] to implement actions to periodically confirm the continued applicability of the [LSTP] conclusions to Seabrook structures. 211 B. NRC Staff Technical Conclusions In the final SE accompanying the March 2019 license amendment, the Staff summarized its review of NextEras methodology for analyzing structures affected by ASR at Seabrook. 212 The Staff reviewed NextEras documentation of its proposed evaluation method and conducted audits. 213 Based on its review, the Staff concluded that NextEras proposed method to evaluate seismic Category I structures affected by ASR is acceptable and provides reasonable assurance that these structures [will] continue to meet the relevant requirements of 10 [C.F.R.]

Part 50, Appendix A, GDC 1, 2, 4, 16 (containment only) and 50 (containment only) and 10

[C.F.R.] Part 50, Appendix B. 214 The Staff based its conclusion on seven criteria. First, the Staff concluded that NextEra met the requirements of GDC 1 by including ASR as a design-basis load and demonstrating 209 Ex. INT024, Final SE at PDF 2.

210 Id. at PDF 40.

211 Id.

212 Id. at PDF 69-70.

213 Id. at PDF 69.

214 Id.

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Official Use Only Proprietary Information that Seabrook ASR-affected structures will continue to meet the requirements of [American Concrete Institute (ACI) 318-71] . . . for all design-basis loads and load combinations[.] 215 Further, the Staff concurred that ACI 318-71 216 is the applicable code to be used based on the research conducted for the LSTP and due to the additional supplementation and modifications made to account for ASR in ACI 318-71. 217 Moreover, the Staff concluded that NextEra developed the LSTP in a manner adequately representative of Seabrook structures, and implemented the LSTP in accordance with quality assurance standards. 218 Second, the Staff concluded that NextEra fulfilled the requirements of GDC 2 by including ASR as a design-basis load and demonstrating that Seabrook ASR-affected structures will continue to meet the requirements of [ACI 318-71] . . . for all design basis loads and load combinations . . . under normal and accident conditions . . . . 219 Third, the Staff concluded that GDC 4 is satisfied because ASR-affected structures will continue to comply with GDC 1 and 2, and because the design-basis loads and load combinations include the dynamic effects associated with missiles, pipe whipping, and discharging fluids. 220 215 Id. at PDF 69-70.

216 There are two codes of record applicable to Seabrook. These two codes form part of Seabrooks licensing design basis regarding concrete structures. The first, ACI 318-71, applies to seismic Category I structures other than containment, while the second, ASME Code Section III, Division 2, applies to containment. See Ex. NRC001-R, Staff Testimony at 68; Ex. NRC049, American Concrete Institute (ACI) Standard 318-71, Building Code Requirements for Reinforced Concrete (1971) [hereinafter Ex. NRC049, ACI 318-71] (non-public); Ex. NRC050,Section III, Division 2, of the 1975 Edition of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code) for Containment [hereinafter Ex. NRC050, ASME Code]

(non-public).

217 Ex. INT024, Final SE at PDF 69.

218 Id.

219 Id.

220 Id.

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Official Use Only Proprietary Information Fourth, the Staff concluded that NextEra satisfied the requirements of GDC 16 and 50 by demonstrating the containment will continue to meet GDC 1 and 2 for all design-basis loads and load combinations including ASR under normal and accident conditions. 221 Fifth, the Staff concluded that NextEra satisfied the applicable requirements in 10 C.F.R. Part 50, Appendix B because NextEra (1) implemented the LSTP under the quality assurance requirements, and (2) established a Structures Monitoring Program to monitor future ASR progression against the LSTP expansion limits and the structure-specific design output threshold monitoring limits[.] 222 Sixth, the Staff concluded that the proposed method of ASR evaluation is acceptable subject to the limitation that measured ASR expansion on affected Seabrook structures is within the limits of the [LSTP] . . . . 223 Finally, the Staff concluded that NextEras implementation of the future confirmatory actions required by the license condition . . . will provide assurance of the continued applicability of the [LSTP] conclusions to Seabrook structures. 224 C. License Condition In issuing the March 2019 Seabrook operating license amendment, the Staff included a license condition that requires NextEra to take specific actions to ensure the continued applicability of the LSTP to concrete structures affected by ASR at Seabrook. 225 This condition has two components. The first requires periodic assessments of ASR expansion using an approach identified in Appendix B of MPR-4273 226 to confirm that future ASR expansion is comparable to the data observed in the LSTP expansion program. 227 Additionally, in 2025 and 221 Id.

222 Id. at PDF 69-70.

223 Id. at PDF 70.

224 Id.

225 See id. at PDF 68-69.

226 Ex. INT019, MPR-4273 app. B; Ex. INT021, MPR-4273, app. B (non-public).

227 Ex. INT024, Final SE at PDF 68.

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Official Use Only Proprietary Information 2035, NextEra must [c]orroborate the concrete modulus-expansion correlation used to calculate pre-instrument through-thickness expansion, as discussed in Report MPR-4153. 228 NextEra stated that it would evaluate the need for changes if the periodic assessments suggest that the monitoring intervals or any other aspect of the SMP are insufficient. 229 Moreover, the license condition requires that NextEra must address any adverse findings from the confirmatory actions in the license condition in accordance with the Corrective Action Program, which is subject to further NRC oversight. 230 Regarding any substantive differences in Seabrook concrete and the concrete used in the LSTP, the Staff found that the license condition provided additional assurance that any variances will not affect public health and safety. 231 D. License Renewal On March 12, 2019, nearly contemporaneously with the Staff issuance of the license amendment, the Staff also approved a twenty-year license renewal for the Seabrook facility. 232 The license amendment applies to the extended operating period granted in the license renewal. 233 The license renewal is not within the scope of this proceeding. 234 228 Id. at PDF 69 (citing Ex. INT018-R, MPR-4153, Revision 3, Seabrook Station-Approach for Determining Through-Thickness Expansion from Alkali-Silica Reaction (Sept. 2017) (Enclosure 4 to Letter SBK-18072) [hereinafter Ex. INT018-R, MPR-4153, Rev. 3]; Ex. INT020, MPR-4153, Revision 3, Seabrook Station-Approach for Determining Through-Thickness Expansion from Alkali-Silica Reaction (Sept. 2017) (Enclosure 6 to Letter SBK-18072) [hereinafter Ex. INT020, MPR-4153, Rev. 3] (non-public)).

229 Ex. NER001, MPR Testimony at 129; Tr. at 1135-37 (Carley).

230 Ex. INT024, Final SE at PDF 68; 10 C.F.R. pt. 50, app. B, Criterion XVI.

231 Ex. NRC001-R, Staff Testimony at 51-52.

232 NextEra Energy Seabrook, LLC; Seabrook Station, Unit No. 1, 84 Fed. Reg. 9563, 9563-64 (Mar. 12, 2019).

233 See generally Ex. INT010, Original LAR.

234 CLI-19-7, 90 NRC at 9; see infra Part VII.B.

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Official Use Only Proprietary Information V. Summary of the Parties Statements of Position A. C-10 On June 10, 2019, C-10 filed its Initial Statement of Position (SOP). 235 In relying on testimony by its expert Dr. Saouma, C-10 disagreed with both the testing and analytical methods conducted by NextEra. 236 C-10 requested that the Board invalidate the LAR and so the associated license amendment and refer the matter to the Commission to determine whether the license renewal should likewise be invalidated. 237 C-10 argued NextEras ASR analysis is lacking in several main areas, specifically that: (1) NextEra did not use concrete that was representative of Seabrook concrete in the LSTP; 238 (2) NextEra did not use specimen dimensions, loads, and boundary conditions representative of Seabrook; 239 (3) NextEra failed to explain the impact of the large horizontal crack that occurred before the shear test on results; 240 and (4) NextEra relied on faulty assumptions about ASR, such as confusing material strength with structural strength. 241 C-10 asserted that these issues render NextEras finite element analysis (FEA) 242 unreliable and undermine the adequacy of parameters used in the 235 [C-10] Initial Statement of Position on C-10s Contentions Regarding NextEras Program for Managing ASR at Seabrook Station Nuclear Power Plant (June 10, 2019) [hereinafter C-10 Initial SOP].

236 Id. at 1-2.

237 Id. at 2, 13-14.

238 Id. at 10.

239 Id.

240 Id.

241 Id. at 11.

242 The FEA is a computational model that includes various elements to collectively . . .

simulate the structural geometry, stiffness, and mass of the desired structure where one can add loads (i.e., demands), such as gravity, wind, or ASR, to the FEA to measure structural responses. See Ex. NER004, SGH Testimony at 39-40; see supra notes 49-54 and accompanying text.

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Official Use Only Proprietary Information ASR expansion monitoring program. 243 Moreover, C-10 suggested that NextEra applied an overly simplistic analytical method to the LSTP data that did not account for the complexities of ASR 244 and that NextEra failed to seek peer review by ASR experts. 245 In sum, C-10 argued NextEra failed to satisfy its burden to show the LAR complies with all applicable legal requirements. 246 C-10 filed a Rebuttal SOP on August 23, 2019, 247 which included additional rebuttal testimony by Dr. Saouma. 248 C-10 emphasized Dr. Saouma is the only expert witness to testify with extensive scientific and engineering experience in the study of ASR, and asserted that the Staff and NextEra lacked sufficient expertise and independent peer review by ASR experts. 249 As such, C-10 argued, the Board should give the expert testimony of Dr. Saouma greater weight than the other experts. 250 243 C-10 Initial SOP at 11.

244 Id.

245 Id. at 12.

246 Id. at 12-13.

247 [C-10] Rebuttal Statement of Position on C-10s Contentions Regarding NextEras Program for Managing ASR at Seabrook Station Nuclear Power Plant (Aug. 23, 2019) [hereinafter C-10 Rebuttal SOP].

248 Ex. INT028, Rebuttal Testimony of Victor E. Saouma, Ph.D Regarding Scientific Evaluation of NextEras Aging Management Program for Alkali-Silica Reaction at the Seabrook Nuclear Power Plant [hereinafter Ex. INT028, Dr. Saouma Rebuttal Testimony] (non-public). A non-proprietary version of Ex. INT028, Dr. Saouma Rebuttal Testimony, was filed by C-10 on September 11, 2019. See Ex. INT032, Rebuttal Testimony of Victor E. Saouma, Ph.D Regarding Scientific Evaluation of NextEras Aging Management Program for Alkali-Silica Reaction at the Seabrook Nuclear Power Plant [hereinafter Ex. INT032, Dr. Saouma Rebuttal Testimony].

249 C-10 Rebuttal SOP at 3.

250 Id.

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Official Use Only Proprietary Information B. NextEra On July 24, 2019, NextEra submitted its SOP, 251 arguing the LAR provides reasonable assurance and complies with applicable regulations. 252 Specifically, NextEra asserted that the LSTP yielded data representative of ASR-affected concrete at Seabrook; 253 the SMP is fully supported, provides reasonable assurance, and complies with applicable regulations; 254 and the Structural Evaluation Methodology (SEM) is adequate. 255 As a threshold matter, NextEra argued C-10 failed to meet its initial burden of moving forward with sufficient evidence to show a deficiency in the LAR. 256 NextEra proffered several supporting arguments: (1) Dr. Saouma either abandon[ed] or contradict[ed] nearly every argument advanced in the original Petition; (2) Dr. Saouma focuse[d] on new challenges to the LAR not contemplated in the original Petition; (3) Dr. Saouma failed to identify an issue in the LAR regarding representativeness; (4) C-10 is incorrect in arguing the LAR is not peer reviewed; (5) NextEras use of linear elastic code-based analysis is appropriate, and C-10 failed to identify a material deficiency in its application; (6) Dr. Saouma failed to fully review the LAR and its complete technical basis; and (7) C-10 seeks to impose requirements beyond those mandated by the reasonable assurance standard. 257 NextEra further argued that C-10 failed to acknowledge the legal and regulatory standards applicable to the LARmuch less demonstrate how the LAR somehow fails to satisfy those standards. 258 251 [NextEra]s Statement of Position (July 24, 2019).

252 Id. at 20-28.

253 Id. at 20-24.

254 Id. at 24-26.

255 Id. at 26-28.

256 Id. at 2.

257 Id. at 3-4, 5 (emphasis omitted).

258 Id. at 4-5 (emphasis omitted).

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Official Use Only Proprietary Information NextEra summarized the qualifications of its experts 259 and asserted that substantial information in the record demonstrates reasonable assurance that Seabrook Station will not endanger the health and safety of the public. 260 Further, NextEra stated that Seabrook would conduct its authorized activities in compliance with applicable regulations. 261 Finally, NextEra concluded that the issuance of the LAR is not inimical to the common defense and security. 262 In rebuttal of C-10s critiques, 263 NextEra alleged that while many of C-10s arguments do not relate to representativeness, those that do result from a disregard of technical documents or a misunderstanding of the programmatic details and/or objectives of the LSTP. 264 NextEra concluded by stating its program addressing ASR is robust, conservative, technically justified, and satisfies the reasonable assurance standard. 265 In sum, NextEra asserted that the Board should resolve the reformulated contention in its favor. 266 C. NRC Staff On July 24, 2019, the Staff submitted its SOP. 267 The Staff found that the LSTP provides reasonable assurance that its data is representative and/or bounding of the progression of ASR at Seabrook. 268 Further, the Staff found that NextEra appropriately used the LSTP data to develop the ASR expansion monitoring program. 269 The Staff maintained that 259 Id. at 10-14.

260 Id. at 9.

261 Id.

262 Id. (citing 10 C.F.R. §§ 50.92, 50.57(a)(3), (6)).

263 Id. at 5, 31.

264 Id. at 31-32.

265 Id. at 37.

266 Id. at 37-38.

267 NRC Staff Initial Written Statement of Position (July 24, 2019) [hereinafter NRC Staff SOP].

268 Id. at 1.

269 Id.

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Official Use Only Proprietary Information 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. 270 According to the Staff, it reviewed each component of the LSTP, finding each one to be representative and/or bounding of the concrete at Seabrook. 271 The Staff further determined that the concrete of the test specimens reasonably reflected the properties of the concrete in Seabrook structures. 272 The Staff also found that the Shear Test Program and Reinforcement Anchorage Test Program were representative and/or bounding of Seabrook structures. 273 The Staff concluded that NextEra appropriately used data from the LSTP to develop the Expansion Monitoring Program. 274 The Staff concluded that NextEras approach to establishing the expansion limits by testing ASR at levels above those found at Seabrook, which resulted in a finding of no reduction in structural capacity, was conservative and appropriate. 275 The Staff provided a rebuttal to each of C-10s arguments. First, the Staff recognized that the concrete aggregate used for the LSTP is not identical. 276 Nonetheless, it argued 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. 277 The Staff also noted that the concrete used in the LSTP had similar specifications to Seabrook 270 Id. at 2.

271 Id. at 33.

272 Id. at 35 (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.).

273 Id. at 36-39.

274 Id. at 43-45.

275 Id. at 43-44.

276 Id. at 46.

277 Id. (citing Ex. NRC001-R, Staff Testimony at 50-52).

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Official Use Only Proprietary Information concrete and used materials similar to the original materials. 278 Additionally, the Staff disputed C-10s argument that a different form of testing should have been done, stating that such an argument is outside the scope of the proceeding as the Staffs review is limited to a finding of reasonable assurance of the selected methods. 279 Further, the Staff argued that C-10 failed to specify how the lack of accelerated expansion tests presents a safety concern. 280 The Staff likewise contended that C-10s arguments regarding a lack of representativeness in the LSTP are not persuasive. 281 The Staff concluded by maintaining that none of the arguments presented by C-10 credibly dispute the Staffs determination that NextEra has provided reasonable assurance that, with the license amendment, as conditioned, Seabrook will continue to meet NRC requirements. 282 VI. Witnesses A. Qualifications of Witnesses

1. C-10s Expert Witness Dr. Victor E. Saouma testified as the sole expert for C-10. Dr. Saouma has a Ph.D. in Civil Engineering from Cornell University and is a Professor of Civil Engineering at the University of Colorado in Boulder. 283 Dr. Saouma is an experienced ASR researcher with over fifteen years of experience in various ASR disciplines. His research has encompassed material and structural testing, theoretical and computational modeling, experimental dynamics, fracture mechanics, and risk-based numerical assessments of bridges, nuclear containment structures, 278 Id. at 46-47.

279 Id. at 47-48.

280 Id. at 48-49.

281 Id. at 49-51.

282 Id. at 48.

283 Ex. INT003, Curriculum Vitae, Dr. Victor E. Saouma at 1-2.

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Official Use Only Proprietary Information and dams. 284 In addition, Dr. Saouma developed a well-known ASR model, published several books, including one on the numerical modeling of ASR, Numerical Modeling of Alkali Aggregate Reaction (CRC Press 2013), and co-authored dozens of peer-reviewed articles on civil engineering topics, including a 2014 article regarding aging management of ASR at Seabrook. 285 Dr. Saouma serves on numerous scientific organizations, committees, and panels, including current Chair of an International Meeting of Laboratories and Experts of Materials, Construction Systems and Structures committee on Diagnosis and Prognosis of ASR affected Structures. 286 Dr. Saouma also has conducted research for various government agencies and has prepared a four-volume report on ASR for the NRC. 287

2. NextEra Expert Witnesses In support of its positions at the evidentiary hearing, NextEra presented eight witnesses:

Michael Collins, the Engineering Site Director for Seabrook; 288 John Simons, the General Manager of Projects with MPR; 289 Christopher Bagley, a Technical Lead and Project Manager 284 Ex. INT001-R, Pre-filed Testimony of Victor E. Saouma, Ph.D Regarding Scientific Evaluation of NextEras Aging Management Program for Alkali-Silica Reaction at the Seabrook Nuclear Power Plant - Corrected June 20, 2019 at 1 [hereinafter Ex. INT001-R, Dr. Saouma Pre-Filed Testimony] (non-public); Ex. INT027, Pre-Filed Opening Testimony of Victor E.

Saouma, Ph.D Regarding Scientific Evaluation of NextEras Aging Management Program for Alkali-Silica Reaction at the Seabrook Nuclear Power Plant - Redacted Version Filed June 26, 2019 at 1 [hereinafter Ex. INT027, Dr. Saouma Pre-Filed Testimony].

285 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 1-2; Ex. INT033, Saouma, V.E. and Hariri-Ardebili, M.A. (2014). A proposed aging management program for alkali silica reactions in a nuclear power plant. Nuclear Engineering and Design 277, pp. 248-264 (non-public).

286 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 30-32.

287 Ex. INT004, Grant Award, Experimental and Numerical Investigation of Alkali Silica Reaction in Nuclear Reactors (2014); Ex. INT005, Experimental and Numerical Investigation of Alkali Silica Reaction in Nuclear Reactors, Grant No. NRC-HQ-60-14-G-0010, Oct. 2014 - Dec. 2017

($703,197).

288 Ex. NER006, Michael Collins Biography.

289 Ex. NER008, John Simons Curriculum Vitae.

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Official Use Only Proprietary Information with MPR; 290 Dr. Oguzhan Bayrak, a Professor of Civil, Architectural, and Environmental Engineering; 291 Edward Carley, the current License Renewal Supervisor for Seabrook, 292 Dr.

Said Bolourchi, a Senior Principal the Engineering Mechanics and Infrastructure practice of Simpson Gumpertz & Heger Inc. (SGH); 293 Glenn Bell, a Senior Principal and the Quality Assurance officer for SGH; 294 and Matthew Sherman, a Senior Principal with SGH. 295 Michael Collins is the Engineering Site Director for Seabrook and has more than thirty-eight years of professional experience in the nuclear power industry. 296 In addition, Mr. Collins is responsible for the engineering management and technical oversight of ASR-related activities at Seabrook and is knowledgeable about the initial detection of ASR at Seabrook, the development of the LAR, and the execution of the SMP. 297 John Simons is the General Manager of Projects with MPR and has more than thirty-two years of professional experience in the nuclear industry. 298 Mr. Simons has first-hand knowledge of NextEras multi-year program to evaluate ASR at Seabrook, including the development and application of the LSTP into the SMP. 299 Christopher Bagley is a Technical Lead and Project Manager at MPR with more than fifteen years of professional experience in the nuclear power industry. 300 Mr. Bagley serves as 290 Ex. NER009, Christopher Bagley Curriculum Vitae.

291 Ex. NER010, Dr. Oguzhan Bayrak Curriculum Vitae.

292 Ex. NER011, Edward Carley Resume.

293 Ex. NER031, [Dr.] Said Bolourchi Curriculum Vitae.

294 Ex. NER032, Glenn Bell Curriculum Vitae.

295 Ex. NER033, Matthew Sherman Curriculum Vitae.

296 Ex. NER006, Michael Collins Biography; Ex. NER001, MPR Testimony at 1-3.

297 Ex. NER001, MPR Testimony at 3.

298 Ex. NER008, John Simons Curriculum Vitae; Ex. NER001, MPR Testimony at 4.

299 Ex. NER001, MPR Testimony at 4-5.

300 Ex. NER009, Christopher Bagley Curriculum Vitae; Ex. NER001, MPR Testimony at 6.

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Official Use Only Proprietary Information a Supervisory Engineer and has first-hand knowledge of NextEras program to evaluate ASR at Seabrook. 301 In addition, he worked on the development and execution of the LSTP, the application of LSTP results to Seabrook, and the methodology for calculating existing ASR expansion. 302 Lastly, he prepared reports for the Electric Power Research Institute (EPRI) on addressing ASR in concrete at nuclear plants. 303 Dr. Oguzhan Bayrak is a Licensed Professional Engineer and a professor at the University of Texas-Austins Cockrell School of Engineering, with more than twenty years of professional experience in structural engineering and over thirteen years of experience related to ASR. 304 Dr. Bayrak has specifically focused on the behavior, analysis, and design of reinforced and prestressed concrete structures, the evaluation of structures in distress, and earthquake engineering. 305 Dr. Bayrak is an ACI Fellow, a member of the Precast/Prestressed Concrete Institute, and Chair of the Federation Internationale du Beton, also known as the International Federation for Structural Concrete. 306 Dr. Bayrak led the LSTP at the FSEL 307 and was the principal investigator and research supervisor for all LSTP efforts conducted at FSEL. 308 Prior to conducting the LSTP, Dr. Bayrak completed four large-scale test programs with field applications and structural assessments for the Texas Department of Transportation. 309 301 Ex. NER001, MPR Testimony at 6-7.

302 Id. at 7-8; Ex. NER009, Christopher Bagley Curriculum Vitae at 1.

303 Ex. NER001, MPR Testimony at 7-8.

304 Ex. NER010, Dr. Oguzhan Bayrak Curriculum Vitae; Tr. at 805 (Bayrak).

305 Ex. NER001, MPR Testimony at 9.

306 Id. at 8-10.

307 Id. at 8-11.

308 Id. at 11.

309 Id. at 10.

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Official Use Only Proprietary Information Edward Carley serves as a Nuclear Engineering Supervisor for Seabrook and has more than thirty-eight years of professional experience in the nuclear power industry. 310 Mr. Carley oversaw NextEras development and regulatory review of the LAR, including the development of the overall approach to the aging management program for ASR in the SMP. 311 Dr. Said Bolourchi is a Licensed Professional Engineer and a Senior Principal at SGH. 312 Dr. Bolourchi has more than forty years of professional experience in the nuclear power industry and has experience related to seismic evaluations of nuclear structures, non-linear modeling, and analysis of highly complex structural loading. 313 He is the Principal-in-Charge for all SGH projects associated with the evaluation of seismic Category I structures at Seabrook. 314 Glenn Bell is a Senior Principal at SGH and a Licensed Professional Engineer. 315 Mr.

Bell has more than forty-four years of professional experience in the structural engineering industry. 316 Previously, Mr. Bell was the CEO of SGH and served on its Board of Directors as Chair. 317 In addition, he is the President-elect of the Structural Engineering Institute and a Board Trustee of the Institution of Structural Engineers (ISE). 318 Lastly, Mr. Bell has first-hand knowledge of the construction of the SEM, supervising the development of ASR load factors for the SEM and the structural analysis for the Containment Building at Seabrook. 319 310 Ex. NER011, Edward Carley Resume; Ex. NER001, MPR Testimony at 12-13.

311 Ex. NER001, MPR Testimony at 13.

312 Ex. NER031, [Dr.] Said Bolourchi Curriculum Vitae; Ex. NER004, SGH Testimony at 1-5.

313 Ex. NER004, SGH Testimony at 2-5; Tr. at 363-64, 1105 (Bolourchi).

314 Ex. NER031, [Dr]. Said Bolourchi Curriculum Vitae.

315 Ex. NER032, Glenn Bell Curriculum Vitae; Ex. NER004, SGH Testimony at 5-6.

316 Ex. NER032, Glenn Bell Curriculum Vitae; Ex. NER004, SGH Testimony at 5.

317 Ex. NER032, Glenn Bell Curriculum Vitae.

318 Ex. NER004, SGH Testimony at 6.

319 Id. at 5.

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Official Use Only Proprietary Information Matthew Sherman is a Senior Principal at SGH and a Licensed Professional Engineer. 320 Mr. Sherman has twenty years of professional experience in both the civil and structural engineering industry, with a focus on construction materials, repair and rehabilitation, and testing. 321 Mr. Sherman is a Fellow at both the ACI and the International Concrete Repair Institute. 322 He has first-hand knowledge of the development of the SEM and oversaw the fieldwork, testing, and petrographic studies associated with the structural evaluation of Seabrook structures affected by ASR, including the application of structural monitoring parameters and frequency of monitoring included as inputs to the SMP. 323

3. NRC Staff Expert Witnesses The Staff presented four witnesses: Angela Buford, a Structural Engineer in NRCs Office of Nuclear Reactor Regulation (NRR), Division of Engineering Structural Engineering Branch; 324 Bryce Lehman, a Civil Engineer in NRR; 325 Dr. George Thomas, a Senior Structural Engineer in NRR; 326 and Jacob Philip, a Senior Geotechnical Civil Engineer in NRCs Division of Engineering, Office of Nuclear Regulatory Research (RES). 327 Angela Buford is a Licensed Professional Engineer with over fifteen years of engineering experience. 328 Ms. Buford has worked for the NRC as a structural engineer and technical reviewer in NRR since 2010. 329 Ms. Buford led a team of structural engineers in evaluating ASR 320 Ex. NER033, Matthew Sherman Curriculum Vitae; Ex. NER004, SGH Testimony at 7-8.

321 Ex. NER033, Matthew Sherman Curriculum Vitae; Ex. NER004, SGH Testimony at 7.

322 Ex. NER004, SGH Testimony at 7.

323 Id. at 8-9.

324 Ex. NRC002, Statement of Professional Qualifications of Angela Buford.

325 Ex. NRC003, Statement of Professional Qualifications of Bryce Lehman.

326 Ex. NRC004, Statement of Professional Qualifications of [Dr.] George Thomas.

327 Ex. NRC005, Jacob [Philip] Testimony.

328 Ex. NRC002, Angela Buford Curriculum Vitae; Ex. NRC001-R, Staff Testimony at 1.

329 Ex. NRC002, Angela Buford Curriculum Vitae.

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Official Use Only Proprietary Information at Seabrook in the context of the facilitys license renewal. 330 Ms. Buford has also worked on three subsequent license renewal audits that addressed several novel technical issues, including irradiation of concrete and steel structures. 331 Additionally, she led an international team of civil and structural engineers in revising the International Generic Aging Lessons Learned report. 332 She has performed numerous briefings on a variety of technical and programmatic topics for congressional staff, the NRC Chairman, the NRC Executive Director for Operations, NRC office directors, the ACRS, NRR division management, the public, and peers. 333 Bryce Lehman is an NRR civil and structural engineer with fifteen years of structural experience, more than ten of which are in nuclear power. 334 Mr. Lehman has performed technical, safety, and regulatory compliance reviews of license amendment requests and relief requests related to structures, including reactor containment buildings. 335 Moreover, he has conducted structural reviews of multiple license renewal applications. 336 Previously, as an employee of Structural Repair Group, Mr. Lehman inspected concrete structures such as condominiums and parking garages to identify structural degradation. 337 As a former Design Engineer for Ralph Whitehead Associates, Inc., Mr. Lehman surveyed and inspected railroad bridges. 338 330 Id.

331 Id.

332 Id.

333 Id.

334 Ex. NRC003, Bryce Lehman Curriculum Vitae; Ex. NRC001-R, Staff Testimony at 1.

335 Ex. NRC003, Bryce Lehman Curriculum Vitae.

336 Id.

337 Id.

338 Id.

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Official Use Only Proprietary Information Dr. George Thomas is a Licensed Professional Engineer and a Senior Structural Engineer in the NRR Division of Engineering. 339 Dr. Thomas has over thirty years of experience as a structural engineer in regulatory work, the private sector, and research. 340 Additionally, he has more than twenty-three years of experience in the United States nuclear industry with both NRC and Bechtel Power Corporation. 341 Dr. Thomas serves as the NRC voting member on the Joint American Society of Mechanical Engineers-American Concrete Institute (ASME-ACI) Code Committee for Concrete Containments. 342 In addition, he has made contributions to the NRCs codes and standards activities, as well as regulatory guidance development related to analysis, design, in-service inspection, and aging management of nuclear safety-related reinforced concrete structures. 343 Jacob Philip is a Licensed Professional Engineer with fifty years of experience and currently is a Senior Geotechnical Engineer in the NRCs Office of Nuclear Regulatory Research (RES), Division of Engineering, Structural, Geotechnical, and Seismic Engineering Branch. 344 Mr. Philip has been with the NRC for almost thirty-nine years and has authored several safety evaluation reports for existing nuclear reactors when he was in NRR. 345 For the last seven years, Mr. Philip has developed and managed research on ASR at the NRC and is the project manager for ASR research at the National Institute of Standards and Technology. 346 339 Ex. NRC004, [Dr.] George Thomas Curriculum Vitae; Ex. NRC001-R, Staff Testimony at 1.

340 Ex. NRC004, [Dr.] George Thomas Curriculum Vitae.

341 Id.

342 Id.

343 Id.

344 Ex. NRC006, Statement of Professional Qualifications of Jacob Philip; Ex. NRC005, Jacob

[Philip] Testimony at 1.

345 Ex. NRC006, Statement of Professional Qualifications of Jacob Philip.

346 Id.

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Official Use Only Proprietary Information B. Admissibility/Weight of Expert Testimony In evaluating the various issues in dispute, the Board must assign the appropriate weight to the testimony of each expert witness according to the witnesss level of expertise. 347 The key qualifications of all the main expert witnesses are enumerated above.

During the hearing, the Board heard from one expert witness from C-10; a multitude of expert witnesses from NextEra and its contractors who were involved in planning, executing and submitting the LAR; and four expert Staff witnesses involved in various aspects of the review and approval of the LAR. At the beginning of the hearing, the Board inquired whether any party objected to the testimony of any expert based on a lack of qualifications. No such objection was raised. 348 Nevertheless, in its Proposed Findings submitted after the evidentiary hearing, NextEra challenged the qualifications of C-10s expert witness, Dr. Saouma, and the bases of his opinions. 349 NextEra would have the Board find that Dr. Saouma is qualified only to provide expert testimony on the topics of ASR and structural engineering, testing, and analysis, and that he is not qualified to testify on the topics of anchors and reinforcement anchorage, NRC licensing and regulation, knowledge of Seabrooks seismic Category I structures, the LAR and its various components, the NRCs oversight of NextEras ASR-related activities and review of the LAR, and engineering practice. 350 347 See Catawba, CLI-04-21, 60 NRC at 31; Shearon Harris, LBP-01-9, 53 NRC at 251 (reasoning that licensing boards should give expert testimony due weight proportionate to their expertise); see also Burkhart v. Wash. Metro. Transit Auth., 112 F.3d 1207, 1212 (D.C. Cir.

1997) (lack of specialization by an expert witness does not disqualify the expert but goes to the weight of the experts testimony).

348 Tr. at 260-61.

349 See NextEras Proposed Findings of Fact and Conclusions of Law at 32.

350 Id.

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Official Use Only Proprietary Information We recognize that Dr. Saouma disavowed any expertise regarding anchors, 351 but that is of no relevance here because C-10 has not made any claim concerning anchors. 352 We also agree that Dr. Saouma is not an expert on NRC regulations, but he was not offered as an expert on the regulations. 353 We reject the remainder of NextEras objections. In general, an expert may be qualified to testify based on knowledge, skill, experience, training, or education. 354 Although Dr. Saouma is not a Licensed Professional Engineer, he is a preeminent researcher in the science of ASR degradation in concrete. 355 His testimony 356 and list of qualifications and experience 357 reveals that he has been a technical consultant on numerous projects related to the management of ASR. We therefore find him qualified to testify regarding sound engineering practice in the management of ASR. 358 351 Tr. at 674 (Saouma) (I confess full ignorance about anchors.); Tr. at 675 (Saouma) (noting he is not in a position to present any testimony to contradict NextEras evidence regarding the LSTP anchor testing); Tr. at 435 (Bayrak) (noting that Dr. Saouma confirmed reinforcement anchorage was outside his area of expertise); Tr. at 266 (Saouma).

352 See generally C-10 Initial SOP; C-10 Rebuttal SOP.

353 It is the duty of the Board to interpret statutes and regulations, subject to Commission review.

Counsel may argue how the law should be interpreted, but in general that is not a proper subject of expert testimony. See Tenn. Valley Auth. (Clinch River Nuclear Site), LBP-18-4, 88 NRC 55, 67 n.70 (2018).

354 See Duke Power Co. (William B. McGuire Nuclear Station, Units 1 & 2), ALAB-669, 15 NRC 453, 475 (1982); Fed. R. Evid. 702.

355 See Ex. INT003, Curriculum Vitae, Dr. Victor E. Saouma.

356 See generally Ex. INT001-R, Dr. Saouma Pre-Filed Testimony (non-public); Ex. INT027, Dr.

Saouma Pre-Filed Testimony; Ex. INT028, Dr. Saouma Rebuttal Testimony (non-public); Ex.

INT032, Dr. Saouma Rebuttal Testimony.

357 See Ex. INT003, Curriculum Vitae, Dr. Victor E. Saouma.

358 See Meridian Mfg., Inc. v. C&B Mfg., Inc., 340 F. Supp. 3d 808, 831 (N.D. Iowa 2018)

(holding expert witness qualified to testify as to the obviousness of design and validity of patent claims, despite not being a licensed professional engineer, where expert had associate degree, bachelor of science degree, and master of science degree in mechanical engineering, as well as 38 years of experience in mechanical engineering and industrial design, and was named inventor of subject matter covered by six patents).

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Official Use Only Proprietary Information We are also not persuaded by the argument that Dr. Saoumas review of the extensive documentation in this case was insufficient to allow him to express opinions regarding the impact of ASR on Seabrook structures. As a general rule, questions relating to the bases and sources of an expert's opinion affect the weight to be assigned that opinion rather than its admissibility and should be left for the [trier of facts] consideration. 359 Dr. Saoumas written testimony explains the documentation he reviewed. 360 He also participated in the plant tour where he had the opportunity to observe the ASR-induced degradation of various Seabrook structures, including the Containment Enclosure Building (CEB). This is a sufficient basis for his expert opinions. To the extent NextEra identified specific relevant documentation that Dr.

Saouma failed to review, that goes to the weight to be afforded his testimony, not its admissibility.

Although it has not directly challenged the qualifications of any particular NextEra or Staff expert witness, C-10 generally challenged the expertise retained by NextEra to develop, and of the Staff to review, the LAR. 361 Specifically, C-10 criticized the lack of adequate ASR expertise of those involved in generating and reviewing the LAR. 362 Those parties include employees of NextEra itself, as well as the FSEL at the University of Texas, MPR, and SGH. 363 359 Viterbo v. Dow Chemical Co., 826 F.2d 420, 422 (5th Cir. 1987); accord Goodrich Ave., LLC

v. Sw. Water Co., 891 F. Supp. 2d 1364, 1382 (M.D. Ga. 2012) (holding that even though wood scientist expert witness never personally observed damage to wood floor in warehouse, he was qualified to testify, for purposes of negligence and trespass trial against water company, as to the damage floor had sustained; in forming his opinion, witness was permitted to consult other sources about the condition and nature of the flooring, and any weaknesses in his testimony went to its weight, rather than its admissibility); see supra note 200 and accompanying text.

360 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 3-5.

361 Id. at 5, 7-9, 34-36; Ex. INT032, Dr. Saouma Rebuttal Testimony at 4, 7-8, 10-12.

362 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 5, 7-9, 36; Ex. INT032, Dr. Saouma Rebuttal Testimony at 4, 7-8, 11-12, 43-44.

363 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 7-9; Ex. INT032, Dr. Saouma Rebuttal Testimony at 7-8 (explaining his opinion that NextEra witnesses have limited expertise on this issue). NextEra witnesses Michael Collins, John Simons, Christopher Bagley, Dr. Oguzhan Official Use Only Proprietary Information

Official Use Only Proprietary Information Moreover, C-10 criticized the lack of ASR expertise of those involved in reviewing the LAR, including the Staff and its contractors, and the ACRS. 364 C-10 emphasized the importance of seeking the expertise of leading researchers in the absence of established standards for evaluating the hazards posed by ASR. 365 Thus, C-10 grounded its criticism in the need to take full advantage of the scientific research that has been performed in studying ASR degradation in concrete.

These C-10 challenges are beyond the scope of this proceeding because no admitted contention makes such a challenge. The sole province of the Board in this decision, particularly after hearing no valid objections to any experts qualifications, 366 is to weigh the expert testimony before us. 367 Insofar as C-10 challenged the credentials of testifying experts, any gaps in testimony will go to the weight of expert testimony, not its admissibility. 368 We will not, however, consider challenges to the experts retained by NextEra to develop, and the Staff to review, the LAR.

VII. Motions in Limine In our June 7 and September 20, 2019 orders issued in response to NextEras first and second Motions in Limine, 369 respectively, we stated that we would defer our ruling on the Bayrak, and Edward Carley are all MPR employees. See generally Ex. NER001, MPR Testimony.

364 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 5, 36; Ex. INT032, Dr. Saouma Rebuttal Testimony at 7-8, 11-12.

365 Ex. INT032, Dr. Saouma Rebuttal Testimony at 7 ([N]one of NextEras or the NRC Staffs witnesses ha[ve] demonstrated previous involvement in the specific study of ASR . . . . The absence of such scientific expertise throughout the investigation and LAR has severely handicapped the LAR process.).

366 Tr. at 260-61.

367 See supra notes 199-204 and accompanying text.

368 See supra note 200 and accompanying text.

369 See NextEras Motion in Limine to Exclude Testimony and Exhibits Regarding Structure Deformation Monitoring (Apr. 23, 2019) [hereinafter NextEra MIL 1]; NextEras Motion in Limine Official Use Only Proprietary Information

Official Use Only Proprietary Information disputed portions of C-10s pre-filed testimony until we had available the full evidentiary record. 370 We now resolve those issues.

In its first Motion in Limine, NextEra argued that the scope of the reformulated contention is limited to the representativeness of the LSTP and certain aspects of the ASR Expansion Monitoring program. 371 NextEra sought to preemptively exclude all allegedly irrelevant and out of scope materials. 372 In its second Motion in Limine, NextEra moved to strike certain portions of C-10s testimony and exhibits deemed irrelevant, immaterial, unduly cumulative, [and]

beyond the scope of the reformulated contention. 373 NextEra disputed several portions of C-10s testimony, including the topics of steel corrosion, testing to the point of failure/the use of alternative methodologies, license renewal, peer review, mineralogy, scaling/boundary conditions, the structural deformation program, design basis loads/load factors, and improper rebuttal testimony. 374 The Staff generally agreed with NextEras motion. 375 In this section, we resolve several of NextEras objections. The remaining rulings on its Motion in Limine objections are addressed below with the Boards analysis of the specific issue to which the objection pertains.

to Strike or Exclude Portions of C-10s Testimony and Exhibits (Sept. 9, 2019) [hereinafter NextEra MIL 2].

370 Licensing Board Order (Deferring Ruling on NextEras Second Motion in Limine) (Sept. 20, 2019) at 2 (unpublished); Licensing Board Order (Ruling on NextEras Motion in Limine) (June 7, 2019) at 1 (unpublished).

371 NextEra MIL 1 at 10.

372 Id. at 11.

373 NextEra MIL 2 at 1.

374 See generally NextEra MIL 2.

375 NRC Staffs Ans. to NextEras Motion in Limine (Sept. 18, 2019) at 1 n.2 [hereinafter Staff Ans. to MIL 2].

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Official Use Only Proprietary Information A. Proper Scope of Rebuttal Testimony NextEra argued that several sections of Dr. Saoumas rebuttal testimony 376 are procedurally improper as they either consist of entirely new arguments, fail to rebut testimony, or impermissibly bolster existing arguments. 377 NextEra cited authority purporting to establish the scope of rebuttal testimony in licensing board proceedings, stating rebuttal testimony is limited to new or surprise material 378 and may not advance any new affirmative claims or arguments that should have been, but were not, included in the partys previously filed initial written statement. 379 The Staff agreed with this argument, 380 while C-10 did not. 381 For the reasons discussed below, we agree with C-10 and decline to apply that strict interpretation of rebuttal testimony to Dr. Saoumas rebuttal testimony, summary of rebuttal testimony, and 376 See Ex. INT028, Dr. Saouma Rebuttal Testimony §§ A.2, A.3, A.9, A.10, A.11, A.14, B.3, B.4, B.6, D.1.1, D.1.2, D.3.2, D.4.1, D.4.2, D.6.1, D.7.1, D.7.2, D.7.4, D.8.2, D.8.3, D.9.1, D.9.2, D.9.3, D.9.4 (non-public); Ex. INT032, Dr. Saouma Rebuttal Testimony §§ A.2, A.3, A.9, A.10, A.11, A.14, B.3, B.4, B.6, D.1.1, D.1.2, D.3.2, D.4.1, D.4.2, D.6.1, D.7.1, D.7.2, D.7.4, D.8.2, D.8.3, D.9.1, D.9.2, D.9.3, D.9.4; Ex. INT029, Summary of Rebuttal Testimony of Victor E.

Saouma, Ph.D Regarding Scientific Evaluation of NextEra's Aging Management Program for Alkali-Silica Reaction at the Seabrook Nuclear Power Plant §§ A.2, A.3, A.9, A.10, A.11, A.14, B.3, B.4, B.6 [hereinafter Ex. INT029, Summary of Dr. Saouma Rebuttal Testimony]; Ex.

INT030-R, [Supplemental] Rebuttal Testimony of Victor E. Saouma, Ph.D Regarding Scientific Evaluation of NextEra's Aging Management Program for Alkali-Silica Reaction at the Seabrook Nuclear Power Plant (Revised) [hereinafter Ex. INT030-R, Dr. Saouma Supp. Rebuttal Testimony].

377 NextEra MIL 2 at 27-31.

378 Rockwell Intl Corp. Rocketdyne Div. (Special Material License Number SNM-21), LBP 27, 30 NRC 265, 269 (1989) (permitting rebuttal testimony only with respect to new or surprise material included in the opposing partys testimony).

379 Progress Energy Fla., Inc. (Levy County Nuclear Power Plant, Units 1 & 2), LBP-09-22, 70 NRC 640, 655 (2009) (Being in the nature of rebuttal, the response, rebuttal testimony, and rebuttal exhibits are not to advance any new affirmative claims or arguments that should have been, but were not, included in the partys previously filed initial written statement.).

380 Staff Ans. to MIL 2 at 5.

381 [C-10s] Opposition to NextEras Second Motion in Limine (Sept. 19, 2019) at 19-20

[hereinafter C-10 Opp. to MIL 2].

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Official Use Only Proprietary Information supplemental rebuttal testimony. 382 However, a few sections of those exhibits, as noted below, fail altogether to meet the requirements of rebuttal testimony in 10 C.F.R. § 2.1207(a)(2).

Therefore, NextEras Motion in Limine with respect to impermissible rebuttal testimony is granted in part, denied in part.

Under 10 C.F.R. § 2.319, a licensing board has the power to [r]estrict irrelevant, immaterial, unreliable, duplicative or cumulative evidence and/or arguments. 383 Commission precedent indicates that a licensing board normally has considerable discretion in making evidentiary rulings. 384 In addition, although licensing boards may refer to the Federal Rules of Evidence for guidance, 385 we are not bound by them. 386 Moreover, licensing boards do not require strict rules of evidence to prevent the presentation of unfair and prejudicial evidence to a 382 Ex. INT028, Dr. Saouma Rebuttal Testimony (non-public); Ex. INT029, Summary of Dr.

Saouma Rebuttal Testimony; Ex. INT030-R, Dr. Saouma Supp. Rebuttal Testimony; Ex.

INT032, Dr. Saouma Rebuttal Testimony.

383 10 C.F.R. § 2.319(e).

384 Catawba, CLI-04-21, 60 NRC at 27.

385 Although we will determine the propriety of Dr. Saoumas rebuttal testimony within the limits imposed by 10 C.F.R. § 2.1207(a)(2), if we found it necessary to refer to the Federal Rules of Evidence for guidance, Supreme Court precedent supports our holding by recognizing that trial judges have the authority to determine the scope of rebuttal testimony [w]ithin limits[.] Geders

v. United States, 425 U.S. 80, 86 (1976); id. at 87 (If truth and fairness are not to be sacrificed, the judge must exert substantial control over the proceedings.). Here, we will determine the propriety of Dr. Saoumas rebuttal testimony within the limits imposed by 10 C.F.R. § 2.1207(a)(2). See Settling Devotional Claimants v. Copyright Royalty Board, 797 F.3d 1106, 1118 (D.C. Cir. 2015) (noting an administrative board has the discretion to limit rebuttal testimony, but is not required to do so); see also Angiuoni v. Town of Billerica, 838 F.3d 34, 40 (1st Cir. 2016) (The wide latitude afforded to trial courts extends to determining whether proposed evidence is proper rebuttal. (quoting United States v. Thuna, 786 F.2d 437, 444 (1st Cir. 1986))); United States v. Sebaggala, 256 F.3d 59, 66 (1st Cir. 2001) (stating trial courts are permitted a wide berth in respect to regulating the scope of rebuttal testimony); Faigin v. Kelly, 184 F.3d 67, 85 (1st Cir. 1999) (The decision to allow or foreclose rebuttal evidence rests squarely within the informed discretion of the district court.); Fed. R. Evid. 611(a) (The court shall exercise reasonable control over the mode and order of interrogating witnesses and presenting evidence so as to . . . make the interrogation and presentation effective for the ascertainment of truth . . . .).

386 S. Cal. Edison Co. (San Onofre Nuclear Generating Station, Units 2 & 3), ALAB-717, 17 NRC 346, 365 n.32 (1983); 10 C.F.R. § 2.319(d).

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Official Use Only Proprietary Information jury, 387 since, in Subpart L proceedings [w]ritten prefiled testimony and exhibits are typically submitted well in advance of the evidentiary hearing, and in our most common types of hearings, the licensing boards themselvesnot the partiesorally examine the witnesses. 388 Therefore, the concerns of unfair prejudice and confusion addressed by the Federal Rules of Evidence are rarely at issue when licensing boards rule on the admissibility of evidence in Subpart L proceedings. 389 To the degree that the regulations governing this Subpart L proceeding define the scope of rebuttal testimony, the delineation is found in 10 C.F.R. § 2.1207(a)(2), which provides that rebuttal testimony must be directed to the initial statements and testimony of other participants. 390 In addition, presiding officers may issue scheduling orders, delineating rules applicable to the proceeding at hand. 391 We issued several scheduling/case management 387 See Old Chief v. United States, 519 U.S. 172, 188 n.9 (1997); Fed. R. Evid. 403.

388 PSEG Power, LLC & PSEG Nuclear, LLC (Early Site Permit Application), LBP-16-4, 83 NRC 187, 210-11 n.171 (2016) (citing 10 C.F.R. § 2.1207).

389 Licensing Board Order (Ruling on Remaining Evidentiary Objections), Crow Butte Res., Inc.

(License Renewal for the In Situ Leach Facility, Crawford, Nebraska), No. 40-8943 (Dec. 6, 2016) at 2 (citing PSEG Power, LBP-16-4, 83 NRC at 210-11 n.171) (unpublished).

390 10 C.F.R. § 2.1207(a)(2).

391 Id. § 2.332.

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Official Use Only Proprietary Information orders throughout this case but declined to define the scope of rebuttal testimony, 392 in accord with a presiding officers broad authority to regulate the conduct of proceedings. 393 NextEra cited four licensing board scheduling orders, two of which are unpublished, that purport to support its narrow definition of rebuttal testimony. 394 However, those licensing board scheduling orders, which at most provide persuasive authority, 395 are merely procedural orders that prescribe the rules for a specific proceeding. 396 Contrary to NextEras argument, procedural scheduling orders do not provide binding precedent in managing the conduct of proceedings or making evidentiary determinations. We therefore decline to apply specific 392 See Order Closing the Hearing Record; Licensing Board Order (Granting C-10s Motion for Leave to File Supplemental Rebuttal Testimony) (Sept. 16, 2019) (unpublished) [hereinafter Order Granting C-10s Motion to File Supplemental Rebuttal Testimony]; Licensing Board Memorandum (Regarding Pre-filed Exhibits) (Aug. 27, 2019) (unpublished); Licensing Board Order (Scheduling Pre-Hearing Teleconference and Providing Instructions) (Aug. 12, 2019)

(unpublished); Licensing Board Order (Providing Case Management Instructions) (May 23, 2019) (unpublished); Licensing Board Memorandum and Order (Revised Scheduling Order)

(Feb. 15, 2018) (unpublished); Licensing Board Order (Initial Scheduling Order) (Nov. 29, 2017)

(unpublished); Licensing Board Order (Identifying hearing procedures, requesting information related to scheduling, and deferring deadlines for production of initial disclosures and the hearing file) (Oct. 26, 2017) (unpublished); Licensing Board Order (Scheduling Oral Argument and Providing Instructions) (June 5, 2017) (unpublished).

393 10 C.F.R. § 2.319; Catawba, CLI-04-21, 60 NRC at 27.

394 NextEra MIL 2 at 8 n.30; Levy, LBP-09-22, 70 NRC at 655; Rockwell, LBP-89-27, 30 NRC at 269; Licensing Board Order (Revised Scheduling Order), Dominion Nuclear N. Anna, LLC (Early Site Permit for North Anna ESP Site), No. 52-008-ESP (Mar. 1, 2006) at 6 (unpublished);

Licensing Board Memorandum and Order (Prehearing Conference Call Summary, Case Management Directives, and Final Scheduling Order), AmerGen Energy Co., LLC (License Renewal for Oyster Creek Nuclear Generating Station), No. 50-0219-LR (Apr. 17, 2007) at 5-6 (unpublished).

395 S. Cal. Edison Co. (San Onofre Nuclear Generating Station, Units 2 & 3), CLI-13-10, 78 NRC 552, 563, 569 n.42 (2013) (Unreviewed board decisions are not binding on future boards . . . .

They may, however, be cited by future litigants as persuasive authority.).

396 Levy, LBP-09-22, 70 NRC at 640 (This initial scheduling order is designed to ensure proper case management of this proceeding[.] (emphasis added)); Rockwell, LBP-89-27, 30 NRC at 266 ([The Administrative Judge] adopted a schedule for the filings in this case and also stated some ground rules that would apply to those filings. (emphasis added)); see also 10 C.F.R. § 2.332(a)-(c) (noting that the presiding officers may establish scheduling orders specific to the proceeding based on the circumstances of the case).

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Official Use Only Proprietary Information statements from past scheduling orders when we did not include such language in the scheduling orders of this proceeding. Rather, we will review each disputed section to determine whether it is responsive to initial testimony, as required by 10 C.F.R. § 2.1207(a)(2).

We find most of Dr. Saoumas rebuttal testimony either explicitly responds to the initial testimony of NextEra or the Staff or it is clear from the subject of the testimony that Dr. Saouma is addressing Staff and/or NextEra initial testimony, in accordance with 10 C.F.R. § 2.1207(a)(2). In section D.6.1 of his rebuttal testimony, although Dr. Saouma does not specify the testimony to which he refers, the Board finds that Dr. Saoumas testimony on relative humidity is responsive to NextEra and Staff testimony (specifically, MPR Q214 and Staff Q.36),

that questions the saliency of relative humidity. 397 In addition, rebuttal testimony sections D.7.1 and D.7.2 respond to initial testimony by Staff and NextEra witnesses that the shear beam test was conducted appropriately, and it is therefore permissible rebuttal testimony. 398 With the exception of section B.4, each section of rebuttal testimony cited by NextEra in its table contains a reference to the initial testimony to which Dr. Saouma responds. 399 We decline to exclude the rebuttal testimony of sections B.3, D.1.1, D.1.2, D.3.2, D.4.2, D.8.2, D.9.1, D.9.2, D.9.3, and D.9.4 as they are responsive to NextEra or Staff initial testimony in accord with 10 C.F.R. § 2.1207(a)(2). 400 Rebuttal testimony section B.4, however, generally stated that NextEra should 397 See Ex. INT028, Dr. Saouma Rebuttal Testimony § D.6.1 (non-public); Ex. INT032, Dr.

Saouma Rebuttal Testimony § D.6.1; Ex. NER001, MPR Testimony at 151-52; Ex. NRC001-R, Staff Testimony at 48-50.

398 See Ex. INT028, Dr. Saouma Rebuttal Testimony §§ D.7.1, D.7.2 (non-public); Ex. INT032, Dr. Saouma Rebuttal Testimony §§ D.7.1, D.7.2; Ex. NER001, MPR Testimony at 142-47; Ex.

NRC001-R, Staff Testimony at 55-57.

399 NextEra MIL 2 at 29-31 tbl.

400 We recognize no specific citations to initial testimony are included for rebuttal testimony section B.3. Id. at 29. However, we find section B.3 responds to initial testimony as it is responsive to Ex. NRC001-R, Staff Testimony at 71-72.

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Official Use Only Proprietary Information have looked beyond the codes. 401 This section is not responsive to any NextEra or Staff initial testimony but appears to restate a previously proffered argument. 402 Section B.4 is therefore excluded from the record as not directed to any of that initial testimony and as duplicative.

Finally, several sections of Dr. Saoumas rebuttal testimony offer no clear connection to NextEra or Staff initial testimony and must therefore be excluded as failing to fulfill the requirements of 10 C.F.R. § 2.1207(a)(2). For example, in rebuttal testimony section A.2, Dr.

Saouma provides more details on his own professional background. This does not appear to address any testimony challenging Dr. Saoumas qualifications but is an attempt to impermissibly bolster his own testimony. 403 Further, rebuttal testimony section A.9, which analogizes ASR to cancer, fails to demonstrate a connection to any NextEra or Staff initial testimony. Section A.9 is thus impermissible rebuttal testimony. 404 Although we largely denied NextEras Motion in Limine with regard to Dr. Saoumas rebuttal testimony, we will apply the appropriate evidentiary weight to that testimony to ensure that [the] hearing[] w[as] fair and produced [an] adequate record[]. 405 B. License Renewal NextEra argued that testimony related to license renewal for the Seabrook facility is beyond the scope of this proceeding. 406 We agree. As stated by the Commission, the Staff 401 See Ex. INT032, Dr. Saouma Rebuttal Testimony § B.4; Ex. INT029, Summary of Dr.

Saouma Rebuttal Testimony § B.4.

402 See Ex. INT027, Dr. Saouma Pre-Filed Testimony at 7, 29-34.

403 See Ex. INT032, Dr. Saouma Rebuttal Testimony § A.3.

404 Id. § A.9.

405 See Statement of Policy on Conduct of Adjudicatory Proceedings, CLI-98-12, 48 NRC 18, 19 (1998); see also N. Anna, ALAB-555, 10 NRC at 26-27. The Board would also like to emphasize that it provided an opportunity for NextEra and the Staff to respond to C-10s supplemental rebuttal testimony, and all rebuttal testimony was filed before the hearing, permitting both parties to address those topics during the hearing in response to Board questions. Order Granting C-10s Motion to File Supplemental Rebuttal Testimony at 4-5.

406 NextEra MIL 2 at 12-13.

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Official Use Only Proprietary Information granted that license renewal in a separate proceeding in which C-10 had the opportunity to participate but did not. 407 NextEras Motion in Limine is granted as to any challenge to the license renewal. 408 C. Evidence from C-10s Emergency Petition NextEra seeks to exclude several exhibits C-10 also filed with its Emergency Petition. 409 Specifically, NextEra seeks to exclude Exhibits INT006, 410 INT007, 411 INT008, 412 and INT009 413 on that basis that all . . . were rejected by the Commission as beyond the scope of the proceeding. 414 Further, NextEra argued that Ex. INT007 is largely duplicative of Dr. Saoumas Testimony, and should be excluded as unduly repetitious, duplicative, and cumulative. 415 C-10, for its part, argued that the Commission did not find all of the supporting documentation for the Emergency Petition beyond the scope of the proceeding. 416 Rather, C-10 argued, the 407 CLI-19-7, 90 NRC at 9 n.50. Nor did C-10 meet the requirements for re-opening the license renewal proceeding. Id. at 9.

408 While the sufficiency of the Seabrook license renewal proceeding is beyond the scope of this proceeding, any modifications or license conditions imposed by this Board will be imposed for the entire period of licensed operation, including under the current licensing term and under the renewed licensing term. See CLI-19-7, 90 NRC at 11 ([A]ny changes resulting from the review of the LAR will be reflected in the license renewal aging management programs.).

409 NextEra MIL 2 at 12, 13-14.

410 Ex. INT006, Declaration of Dr. Victor E. Saouma, Ph.D (Feb. 12, 2019).

411 Ex. INT007, Saouma, Review of Selected Documents Pertaining to the Structural Evaluation of Seabrook Nuclear Power Plant (Feb. 12, 2019) [hereinafter Ex. INT007, Dr. Saouma Review of Selected Documents] (non-public). Ex. INT031 is the pubic version of Ex. INT007. See Ex.

INT031, Saouma, Review of Selected Documents Pertaining to the Structural Evaluation of Seabrook Nuclear Power Plant (Feb. 12, 2019) [hereinafter Ex. INT031, Dr. Saouma Review of Selected Documents].

412 Ex. INT008, Saouma, Review of Selected Documents Pertaining to the Structural Evaluation of Seabrook Nuclear Power Plant (Feb. 12, 2019).

413 Ex. INT009, Reply Declaration of Victor E. Saouma, Ph.D (March 1, 2019).

414 NextEra MIL 2 at 13.

415 Id.

416 C-10 Opp. to MIL 2 at 10.

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Official Use Only Proprietary Information Commission made a general observation that some material submitted was beyond the scope of the proceeding. 417 We agree with C-10 and decline to exclude the exhibits from C-10s Emergency Petition.

As an initial matter, we note that the Commission did not explicitly find that each of the above-listed documents contained information beyond the scope of the proceeding. 418 Rather, the Commission noted generally that C-10s [emergency] petition raises issues encompassed by its admitted contention, as well as some that are beyond its scope. 419 Therefore, we are not persuaded by NextEras argument that we should exclude these exhibits as beyond the scope of the proceeding.

In addition, we find that Ex. INT007 is not unduly repetitious, duplicative, or cumulative, 420 and in certain instances, the exhibit provided additional probative testimony useful to the Board. Therefore, we decline to exclude it. The Board was neither prejudiced nor burdened in reviewing Ex. INT007. NextEras Motion in Limine seeking to exclude Exhibits INT006, INT007, INT008, and INT009 is denied. 421 With these NextEra challenges to the contents of the evidentiary record thus resolved, we turn to our resolution of the merits of the reformulated contention.

417 Id.

418 CLI-19-7, 90 NRC at 6.

419 Id. at 7.

420 NextEra MIL 2 at 13.

421 Although some parts of Exhibits INT006, INT007/INT031, INT008, and INT009 may be immaterial, irrelevant, or unduly cumulative, but using our judgment to review the materials and cite the relevant testimony is more efficient and fairer than a wholesale exclusion of these exhibits. On a practical note, we hardly relied on these exhibits in reaching our decision. Ex.

INT007/INT031 is the only one of these exhibits cited in our Initial Decision for its substantive material and is cited in only 8 of over 1,200 footnotes.

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Official Use Only Proprietary Information VIII. Findings of Fact and Board Analysis of Disputed Issues A. Representativeness of the LSTP In the discussion below, we consider two questions regarding the LSTP undertaken for NextEra at the FSEL. First, is the data yielded by the study representative of the progression of ASR at Seabrook and second, are the proposed monitoring, acceptance criteria, and inspection intervals adequate to address the progression of ASR. We address several representativeness issues in this section, beginning with concrete mineralogy, test specimen scaling, boundary conditions, and conclude with the effect of reinforcement. In addition, before delving into a substantive discussion of each of these issues, we address the outstanding objections from the Motions in Limine.

1. General Findings Related to Representativeness ASR is a [worldwide] known concrete pathology [caused by] chemical reactions between amorphous or poorly crystallized silica contained within reactive aggregates and ions from the pore solution of concrete (hydroxyls, alkalis and calcium ions). 422 As a result, ASR leads to progressive destruction of reactive aggregates and precipitation of reaction products called gels whose composition may vary depending on local chemical equilibrium. 423 Concrete structures affected by ASR exhibit cracking, displacements, structural deformations, pop-outs and reduction in mechanical performances. Service of structures may be severely affected. Gels are usually supposed to be the main cause of the induced swelling and degradations. 424 422 Ex. INT034, S. Poyet et al., Chemical modelling of Alkali Silica reaction: Influence of the reactive aggregate size distribution (2006) at 230 [hereinafter Ex. INT034, Poyet et al.] (non-public).

423 Id. (non-public).

424 Id. (non-public).

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Official Use Only Proprietary Information The cracking resulting from ASR is described as map or pattern cracking and is typically accompanied by dark staining adjacent to cracks on the surface of the structure. 425 One indicator of ASR in degrading concrete is the presence of alkali-silica gel. 426 A visual inspection of the degraded concretes cracking pattern may also indicate ASR. 427 Evaluations of structural adequacy are exercises to determine whether the demands (i.e., load effects) on a structure or its elements exceed the capacities (e.g., strength or stress limits) of the structure or its elements. Methods of determining appropriate demands and capacities are prescribed by specific criteria, standards, and codes. 428 At Seabrook, safety-related structures other than the containment are designed and constructed to comply with the 1971 edition of American Concrete Institute Standard 318, Building Code Requirements for Reinforced Concrete (ACI 318-71). 429 The containment structure is 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. 430 Generally speaking, ASR was not a known issue in concrete until the early 1980s. 431 ACI 318-71 and the ASME Code do not include provisions for the analysis of structures affected by ASR. 432 425 Ex. NER018, MPR-3727 at 1.2.2.

426 Ex. INT010, Original LAR at PDF 9, 64-65.

427 Id.

428 Ex. NER004, SGH Testimony at 16.

429 Ex. INT010, Original LAR at PDF 13; see Ex. NRC049, ACI 318-71 (non-public).

430 Ex. INT010, Original LAR at PDF 14; see Ex. NRC050, ASME Code (non-public).

431 Ex. NER019, Bayrak, O., Structural Implications of ASR; State of the Art (Feb. 2,2012)

(FP100697) at 19 (Earnest efforts to establish the implications of ASR with respect to the various limit states of concrete structures (axial, flexural, shear, and anchorage strength among others) did not begin until the early 1980's.) [hereinafter Ex. NER019, Bayrak White Paper]

(non-public).

432 Ex. INT010, Original LAR at PDF 7; see also id. at PDF 11 (These codes do not include methods to address the effects of ASR on the structural properties used in the design of Official Use Only Proprietary Information

Official Use Only Proprietary Information Therefore, NextEra devised its own methodology to evaluate the effects of ASR on the structural properties of seismic Category I structures at Seabrook. To support a long-term assessment of the impact of ASR on plant structures and provide a more realistic technical basis for a monitoring program, [MPRa consultant to NextEra] included a recommendation to perform large-scale testing to obtain more representative data than were available in public literature. 433 The LSTP is the basis for a large part of NextEras methodology. 434 The LSTP involved testing large concrete specimens constructed to reflect the structural characteristics of ASR-affected structures at Seabrook. 435 NextEra concluded that the LSTP was the best means by which to evaluate the impact of ASR on structural performance, instead of testing cores taken directly from Seabrook structures. 436 The FSEL performed the tests on the constructed specimens. 437 FSEL conducted tests on the concrete specimens to reflect various levels of ASR cracking and to assess the impact on selected limit states. 438 These tests included all relevant limit states except compression (i.e., flexure and reinforcement anchorage, shear, and anchor bolts and structural attachments to concrete). 439 NextEra determined that [t]he results of the test program demonstrated that none of the assessed limit states are reduced by ASR when concrete structures . . . . The analyses and testing to assess ASR material effects established a method to incorporate ASR into the Seabrook design basis that is not described in either ACI 318-71 or the ASME Code.); Ex. INT022, SEM at PDF 12 (Neither ACI 318-71 nor the ASME code include provisions for the analysis and evaluation of structures affected by ASR.); Tr. at 946 (Buford).

433 Ex. NER001, MPR Testimony at 55.

434 Ex. INT010, Original LAR at PDF 15.

435 Id.

436 See Ex. NRC001-R, Staff Testimony at 24.

437 Id.

438 Ex. INT010, Original LAR at PDF 15; see supra note 38.

439 Ex. INT010, Original LAR at PDF 16.

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Official Use Only Proprietary Information ASR expansion levels in plant structures are below those evaluated in the [LSTP]. 440 As long as ASR expansion levels are below those limits, NextEra concluded Seabrook structures will have strength close to or in excess of that envisaged in the original design or as required by the code, 441 despite the effect of ASR on the material properties of Seabrook concrete.

NextEra used LSTP test data to support other conclusions in the LAR. One of these was the effectiveness of the use of CCI to monitor the effects of ASR on the surface of Seabrook structures. The purpose of the ASR Expansion Monitoring Program is to gather crack width and extensometer measurements for monitoring against specified acceptance criteria (i.e.,

the ASR expansion limits) based on the LSTP to ensure ASR-related expansion at Seabrook does not exceed levels observed in the LSTP. 442 According to the LAR:

One of the objectives of the test program was to identify effective methods for monitoring ASR. The program concluded that monitoring the in-plane and through-thickness expansion is effective for characterizing the significance of ASR in structures. A [CCI] methodology based on crack width summation was shown to be effective for in-plane expansion monitoring. Snap ring borehole extensometers . . . provided accurate and reliable measurements for monitoring through-thickness expansion. 443 The CCI estimates expansion on a concrete surface using measurements of crack widths along a pre-determined length or grid. 444 The CCI is the weighted average of the CI in the two measured in-plane directions (horizontal and vertical) at the concrete surface. 445 CI and CCI are similar yet distinct terms. CI is [a] crack width summation technique for quantitatively 440 Id.

441 Id. at PDF 15.

442 Ex. NER007, Seabrook [SMP] Manual Rev. 7 at 3-1.3, 3-1.7 to -1.8 (non-public).

443 Ex. INT010, Original LAR at PDF 17; see also Tr. at 326-27 (Bayrak) (confirming that the CCI methodology was validated in the LSTP).

444 Ex. NER022-R, MPR-4262, Shear and Reinforcement Anchorage Testing of Concrete Affected by Alkali-Silica Reaction, Vol. I, Rev. 1 (July 2016) & Vol. II, Rev. 0 (Jan. 2016)

(FP100994) at 5-2 [hereinafter Ex. NER022-R, MPR-4262] (non-public).

445 Ex. NER004, SGH Testimony at 34.

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Official Use Only Proprietary Information estimating tensile strains experienced by a reinforced concrete element. The [CI] is the ratio of the sum of crack widths to the length of which the crack summation activity is performed (i.e.,

the [gauge] length.). 446 CCI is [a] term used at Seabrook Station for a combination of [CI]

values in both the horizontal and vertical directions. 447 For the LSTP specimens, although the rate of expansion was approximately the same in all three directions until expansion reached to millimeters per meter (mm/m) (i.e.,  %

to  %), the specimens subsequently exhibited much greater expansion in the through-thickness direction than the in-plane directions. 448 These observations led MPR to conclude that using the CCI to monitor in-plane expansion sufficiently characterizes ASR development until at least 1.0 mm/m (0.1%) expansion, after which through-thickness monitoring by extensometers is required to monitor further ASR expansion. 449 NextEra relied on the results of the LSTP to support the installation of extensometers at an in-plane expansion of 1.0 mm/m (0.1%). 450 Under the LAR, locations with no symptoms of ASR (Tier 1 areas) are generally inspected every five or ten years based on the existing SMP requirements. 451 Inspectors monitor locations with ASR symptoms that have CCI values below 1.0 mm/m (0.1%) in-plane expansion (Tier 2 areas) every two and a half years. 452 Locations with CCI values of 1.0 mm/m 446 Ex. NER002, MPR Testimony - Attachment 1 - Glossary at 2 [hereinafter Ex. NER002, MPR Glossary].

447 Id. at 1.

448 Ex. NER001, MPR Testimony at 91.

449 Ex. INT019, MPR-4273 at B-4; Ex. INT021, MPR-4273 at B-4 (non-public).

450 Ex. NER001, MPR Testimony at 122.

451 Ex. NER007, Seabrook [SMP] Manual Rev. 7 at 2-1.7 to -1.8 (non-public); Ex. NER001, MPR Testimony at 126.

452 Ex. INT010, Original LAR at PDF 33 tbl.5.

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Official Use Only Proprietary Information (0.1%) or greater (Tier 3 areas) are monitored for in-plane expansion, through-thickness expansion, and volumetric expansion every six months. 453 Acceptance criteria for expansion levels directly incorporate LSTP conclusions. 454 LAR Table 4 and UFSAR Table 3.8-18 provide the ASR expansion limits (i.e., acceptance criteria) intended to ensure that expansion remains within the parameters validated by the LSTP results for Seabrook structures, i.e., that ASR does not reduce the assessed limit states. 455 Table 4 includes through-thickness expansion limits for shear, flexure, and reinforcement anchorage, as well as in-plane expansion limits for anchorage. 456 A CCI measurement of 1.0 mm/m (0.1%) or greater expansion provides the threshold for the installation of extensometers to determine compliance with the LAR Table 4/UFSAR Table 3.8-18 expansion limits. 457 NextEra justified the use of extensometers to monitor expansion in the Tier 3 areas based on the LSTP. As the LAR explains:

NextEra is installing extensometers for measuring through-thickness expansion of plant structures. The extensometer is installed in a borehole that is perpendicular to the face of the wall (or slab). The instrument consists of two anchors and a rod. The rod is attached to the anchor installed deep in the borehole and slides through a hole in the anchor installed near the surface.

Expansion is monitored by measuring the distance between the end of rod and the reference surface on the anchor near the surface. The extensometer being installed is a snap-ring borehole extensometer. It was selected because it was shown to be accurate and reliable in the [LSTP]. 458 The LSTP results were also used by MPR to evaluate the impact of ASR on the material properties of Seabrook concrete and to determine whether changes to those properties reduce 453 Id.

454 Ex. NER001, MPR Testimony at 112.

455 Ex. INT010, Original LAR at PDF 17, 32 tbl.4.

456 Id. at PDF 32 tbl.4.

457 Id. at PDF 32 tbl.4, 74 tbl.3.8-18.

458 Id. at PDF 31.

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Official Use Only Proprietary Information the capacity of Seabrook structures. 459 The material properties of concrete include compressive strength, tensile strength, and elastic modulus. 460 Staff witnesses stated that [t]he compressive strength of a material, including concrete, is its capacity to withstand loads or stresses that tend to compress and reduce its size, as opposed to tensile strength, which is its capacity to withstand loads or stresses that tend to elongate and crack or split the material. 461 Further,

[t]he elastic modulus is the ratio of stress (force per unit area) to strain (ratio of change in length to the original length) in the elastic range of material behavior. 462 In addition, [t]he elastic range of a material is the range in which the material can be loaded and unloaded without permanent deformation (i.e., an elastic structure deforms when a load is applied and, when the load is removed, it returns to its original state). 463 The Staff defined shear strength as the ability of a material to resist shear stress, . . . created when two planes of the same object attempt to slide past one another. 464 On the other hand, [f]lexural strength (or bending strength) is the ability of a structural member to resist a flexural load (moment), or the members ability to resist bending when loaded. 465 NextEra described the details of reinforced concrete, stating:

Reinforced concrete is fabricated by placing wet (i.e., fresh) concrete into forms that contain mats of reinforcing bars . . . . The concrete mixture is then allowed to cure, such that it is bonded to the steel bars. In general, plain concrete (unreinforced) is relatively strong in compression (i.e., loads that push the 459 Ex. 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) at 9, 11

[hereinafter Ex. INT014, MPR-4288] (non-public); Ex. 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) at 9, 11 [hereinafter Ex. INT012, MPR-4288].

460 Ex. NER001, MPR Testimony at 39.

461 Ex. NRC001-R, Staff Testimony at 7.

462 Id.

463 Id.

464 Id.

465 Id.

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Official Use Only Proprietary Information concrete together) and relatively weak in tension (i.e., loads that pull the concrete apart). The purpose of using reinforcing bars is to provide tensile capacity. In effect, tensile strength of concrete is not relied upon for many aspects of structural design, because tensile strength of typical concrete mixtures is roughly a tenth of the compressive strength of those mixtures. Reinforced concrete can be viewed as a composite, custom-made, structural material where concrete is used for its superior capacity in compression, and reinforcing steel is used to provide tensile strength, where needed. 466 Among other things, MPR evaluated the material properties of cores obtained from the LSTP specimens before testing, which indicated reductions in compressive strength, elastic modulus, and splitting tensile strength with increasing ASR-related expansion. 467 When a core is removed from one of the test specimens, however, the confining effect of the steel reinforcement is lost. 468 MPR relied upon the testing of the reinforced concrete specimens to conclude that evaluations of Seabrook structures should be based on the original material properties of the concrete rather than the degraded material properties identified in the core evaluations. MPR stated:

Design Concrete Material Properties - Published literature identified that ASR reduces unconfined material properties of concrete (compressive strength, elastic modulus, tensile strength), which is consistent with the results obtained in the [LSTP]. However, the [LSTP] results also showed that the reduction in concrete material properties does not harm the structural performance of ASR-affected structures when through-thickness expansion is less than [ mm/m or]

%. These results confirm that structural performance of reinforced concrete structures cannot be reasonably re-evaluated for ASR simply by adjusting the ASR-affected properties of unconfined concrete and neglecting the self-equilibrating state of stress due to ASR-induced prestress. Based on this observation, structural evaluations of ASR-affected structures at Seabrook Station should conservatively use the material properties specified in the original design specifications. 469 466 Ex. NER001, MPR Testimony at 34.

467 Ex. NER022-R, MPR-4262 at 8-12 (non-public).

468 Ex. INT012, MPR-4288 at 6-9.

469 Id. at 2-3; Ex. INT014, MPR-4288 at 2-3 (non-public); see also Ex. INT019, MPR-4273 at 5-7 (Because the [LSTP] specimens were much more representative of Seabrook Station than published literature . . . and the [LSTP] results were highly repeatable, structural evaluations for Seabrook Station can use the [LSTP] conclusion (i.e., no loss of capacity) in lieu of the results from published literature.).

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Official Use Only Proprietary Information Similarly, MPR relied upon the LSTP results to justify the use of the equations from ACI 318-71 and the 1975 ASME Code in its structural evaluations. 470 The capacity of Seabrook structures to withstand the loads (i.e., the demand) on those structures, including the additional load created by ASR, was determined using the code equations, which had been justified by the LSTP. 471 Finally, NextEra relied on a correlation developed in the LSTP to determine the total through-thickness expansion in the Tier 3 locations, the locations with CCI values of 1.0 mm/m (0.1%) or greater. 472 Installation of extensometers provides a means for monitoring expansion from the time that the instrument is installed. 473 For structural evaluations at Seabrook, however, NextEra must be able to determine the total expansion that has occurred in a location affected by ASR from the original construction, which includes both the expansion measured by the extensometer and the expansion before the extensometer installation. 474 NextEra combined the expansion at such locations measured by the extensometers with the expansion that occurred up to the time of instrument installation to yield the total through-thickness expansion to a given time. 475 To determine the expansion before instrument installation, NextEra tested cores removed from the boreholes that housed the extensometers to measure the current elastic 470 Tr. at 582 (Bell) (The validity of the code equations were amply demonstrated by the very extensive testing of the [LSTP].).

471 Tr. at 965 (Bell) (The finite element analysis does the demand side. It determines the internal forces. The capacity is determined by the code equations, justified by the [LSTP].); Tr.

at 965 (Bolourchi) ([W]e are saying ASR expansion, it increases the load, the total demand, but it does not decrease the capacity. Therefore, the capacity [calculated using code equations] is verified by [the LSTP].).

472 Ex. INT010, Original LAR at PDF 33 tbl.5.

473 Ex. NER001, MPR Testimony at 18, 117.

474 Ex. INT018-R, MPR-4153, Rev. 3 at iv; Ex. INT020, MPR-4153, Rev. 3 at iv (non-public).

475 Ex. INT010, Original LAR at PDF 31.

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Official Use Only Proprietary Information modulus of those core samples. 476 It then used an empirical correlation developed in the

[LSTP] to correlate concrete elastic modulus measurements with the through-thickness expansion to date. 477 According to NextEra, combining past expansion with the future expansion detected by the extensometers provides a total measure of through-thickness expansion in areas affected by ASR. 478 The accuracy of the correlation is essential to verifying regulatory compliance because total through-thickness expansion is one of the measurements that ensures expansion remains within limits validated by the LSTP results for Seabrook structures. 479 Thus, the LSTP played a critical role in determining the acceptable limits of ASR expansion for Seabrook structures, the monitoring of those structures to ensure that the limits are not exceeded, and the equations used to calculate the structures capacity to withstand the loads placed upon them. The expansion limits and monitoring program, which were based on the results of the LSTP, will be used to determine the regulatory compliance of Seabrook structures through the end of the extended licensethat is, for the next thirty years. 480 Because the LSTP evaluated the effects of ASR on test specimens, not actual Seabrook concrete, the LSTP data is reliable and may be used to support the critical safety-related determinations described above only if the test specimens are representative of Seabrook 476 Ex. INT018-R, MPR-4153, Rev. 3 at 4-1; Ex. INT020, MPR-4153, Rev. 3 at 4-1 (non-public).

477 Ex. INT010, Original LAR at PDF 31; see also Ex. INT018-R, MPR-4153, Rev. 3 at iv (The correlation relates reduction in elastic modulus with measured expansion from beam specimens used during the large-scale ASR structural testing programs and provides a conservative estimate of pre-instrument expansion levels at Seabrook Station.); Tr. at 1001 (Carley) (The modulus correlation was developed using only data from the [LSTP].).

478 See Ex. INT010, Original LAR at PDF 31-32.

479 Id. at PDF 17, 32 tbl.4 480 See supra Part IV.D.

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Official Use Only Proprietary Information seismic Category I structures. Application of the LSTP results requires that the test specimens be representative of reinforced concrete at Seabrook. 481 We accept NextEras definition of representativeness as [t]he ability to apply conclusions from one application to inform circumstances in another application. In the context of the reformulated contention, representativeness refers to the results from the LSTP and their applicability to reinforced concrete structures at Seabrook Station. 482 To design the test specimens for the LSTP, MPR selected a reference location at Seabrook. The chosen location was a horizontal section of the west wall of the B Electrical Tunnel. 483 That tunnel was the first location where ASR was identified at Seabrook. 484 NextEra concluded it was reasonable to use the B Electrical Tunnel as the reference location because the levels of ASR cracking there are similar to other areas, the thickness of the walls (2 feet) is consistent with most other areas, and the reinforcement configuration is typical of most other structures. 485 According to MPR, the final design of the test specimens must:

• [B]e representative of the reference location so that the test results can be used to calculate its structural capacity for the given failure modes,

• [U]se materials that are representative of the material of construction of the reference location, 481 See Ex. NER001, MPR Testimony at 20 (For th[e LSTP] approach to be successful, the basis for the knowledge must be sufficiently representative of the object in question to be applicable.); Ex. INT019, MPR-4273 at 5-7 (Because the [LSTP] specimens were much more representative of Seabrook Station than published literature . . . and the [LSTP] results were highly repeatable, structural evaluations for Seabrook Station can use the [LSTP] conclusion (i.e., no loss of capacity) in lieu of the results from published literature.).

482 Ex. NER002, MPR Glossary at 3.

483 Ex. NER001, MPR Testimony at 76-77.

484 Id.

485 Ex. NER026, MPR-3757, Rev. 4 Shear and Reinforcement Anchorage Test Specimen Technical Evaluation (May 2014) at 12 [hereinafter Ex. NER026, MPR-3757] (non-public).

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• [B]e sufficiently representative to the other structures at Seabrook Station such that the test results can be applied to those structures using adjustments derived from extensive published data,

• [E]nsure failure in the desired failure mode (out-of-plane shear and reinforcement anchorage, respectively), and

• [A]llow for the rapid development of ASR. 486

2. Concrete C-10 argued the composition of the LSTP concrete was not representative of Seabrook concrete. 487 Concrete is comprised of (1) coarse and fine aggregates, (gravel and sand, respectively) that provide strength; (2) cement, which functions as a glue that holds the aggregates together; and (3) water for cement hydration, which is the set of chemical reactions that transforms the cement from a dry powder to the glue that bonds the concrete constituents together. 488 Dr. Saouma testified that NextEra used a different aggregate in the LSTP specimens than that used in Seabrook concrete. 489 In particular, NextEra used a blend of highly reactive coarse aggregate and slow reacting coarse aggregate along with sand as opposed to the coarse aggregate present at Seabrook. 490 Dr. Saouma stated that the LSTP aggregate mixture does not have the same reactivity as Seabrook aggregate. 491 He further testified that the cracking pattern that you have as the result of sand being the driving force as opposed to the 486 Id. at 16 (non-public).

487 C-10 Initial SOP at 10.

488 Ex. NER001, MPR Testimony at 34; see also Ex. INT031, Dr. Saouma Review of Selected Documents at 3 (Concrete is a delicate dosage of cement, aggregates (about 3/4 max), sand and water designed to meet specific criteria.).

489 Ex. INT001-R, Dr. Saouma Pre-Filed Testimony (non-public) at 10-11; Ex. INT027, Dr.

Saouma Pre-Filed Testimony at 10-11; Tr. at 632 (Saouma).

490 Ex. INT001-R, Dr. Saouma Pre-Filed Testimony (non-public) at 10-11; Ex. INT027, Dr.

Saouma Pre-Filed Testimony at 10-11; Tr. at 604, 1001-02 (Saouma).

491 Tr. at 632-33 (Saouma).

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Official Use Only Proprietary Information aggregate is quite different. 492 In his opinion, the cracking pattern observed in the LSTP specimens is not representative of what would happen at Seabrook. 493

a. Motion in Limine At the outset, we must address NextEras claim that testimony concerning concrete mineralogy is beyond the scope of the reformulated contention. 494 We find that both the physical and chemical properties of concrete (i.e., its mineralogy) are fairly encompassed by the description of [the admissible contentions] that [C-10] set forth in its petition for hearing. 495 The Motion in Limine is denied in this respect.

An evidentiary hearing convened in response to an intervenor challenge to a proposed agency licensing action is limited to any admitted contentions. The reach of a contention necessarily hinges upon its terms coupled with its stated bases. 496 Intervenors are not required to prove their case at the contention stage, nor are they required to provide an exhaustive list of possible bases at that time. 497 But an intervenor may not freely change the focus of an admitted contention at will to add a host of new issues and objections that could have been 492 Tr. at 604 (Saouma).

493 Ex. INT001-R, Dr. Saouma Pre-Filed Testimony at 11 (non-public); Ex. INT027, Dr. Saouma Pre-Filed Testimony at 11.

494 NextEra MIL 2 at 16, 17.

495 Entergy Nuclear Generation Co. & Entergy Nuclear Operations, Inc. (Pilgrim Nuclear Power Station), CLI-10-11, 71 NRC 287, 310 (2010).

496 Pilgrim, CLI-10-11, 71 NRC at 309 (citing Pub. Serv. Co. of N.H. (Seabrook Station, Units 1

& 2), ALAB-899, 28 NRC 93, 97 (1988), affd sub nom. Mass. v. NRC, 924 F.2d 311 (D.C. Cir.),

cert. denied, 502 U.S. 899 (1991); Duke Energy Corp. (McGuire Nuclear Station, Units 1 & 2; Catawba Nuclear Station, Units 1 & 2), CLI-02-28, 56 NRC 373, 379, 383 (2002)).

497 La. Energy Servs., LP (Natl Enrichment Facility), CLI-04-35, 60 NRC 619, 623 (2004); see also Calvert Cliffs Nuclear Project, LLC, and Unistar Nuclear Operating Servs., LLC (Calvert Cliffs Nuclear Power Plant, Unit 3), LBP-12-17, 76 NRC 71, 85 (2012) ([A]s long as the facts relied on by [the Intervenor] fall within the envelope of the contention, they are properly before the Board. A petitioner is not required to set forth all of its evidence or to prove its contentions at the admissibility stage.); Nuclear Innovation N. Am. LLC (S. Tex. Project, Units 3 & 4), LBP-11-25, 74 NRC 380, 397 (2011) (At the contention admissibility stage of a proceeding, Intervenors need not marshal their evidence as though preparing for an evidentiary hearing.).

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Official Use Only Proprietary Information raised at the outset. 498 When an intervenors testimony or exhibits are alleged to fall outside the scope of an admitted contention, licensing boards must decide whether the proffered evidence is within the reasonably inferred bounds of the admitted contention. 499 Information offered in evidence, even if not specifically stated in the original contention and bases[, may] be relevant if it falls within the envelope, reach, or focus of the contention when read with the original bases offered for it. 500 Contentions A, B, C, D, and H provided the bases of the reformulated contention, and we will therefore look to those contentions and the facts C-10 alleged in support to determine whether specific issues fall within the scope of the reformulated contention. 501 The reformulated contention alleges that the LSTP data fails to represent the progression of ASR at Seabrook adequately and therefore fails to provide an adequate basis for establishing monitoring, inspection criteria, and inspection intervals. 502 On its face, the reformulated contention is broad enough to cover any failure of the LSTP data to adequately represent the effect of ASR on Seabrook structures, provided that such failure is related to establishing monitoring, inspection criteria, or inspection intervals.

Contention D, one of the bases of the reformulated contention, alleged that the LSTP data fails to represent the progression of ASR at Seabrook adequately. 503 As the Commission noted, [i]n Contention D, C-10 challenges the overall representative nature of the data from the 498 Licensing Board Order (Ruling on NextEras Motion in Limine) (June 7, 2019) at 7 (unpublished) (quoting McGuire, CLI-02-28, 56 NRC at 386).

499 Pilgrim, CLI-10-11, 71 NRC at 309.

500 Duke Energy Corp. (Catawba Nuclear Station, Units 1 & 2), LBP-04-12, 59 NRC 388, 391 (2004).

501 See supra Part II.B.

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

503 C-10 Petition at 2, 8-11.

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[LSTP]. 504 Quoting the LAR, Contention D emphasized that [a]pplication of the results of the

[LSTP] requires that the test specimens be representative of reinforced concrete at Seabrook Station and that expansion behavior of concrete at the plant be similar to that observed in the test specimens. 505 Like the reformulated contention, Contention D implies that the allegedly inadequate test data fails to provide a sufficient basis for establishing any monitoring program or methodology. Therefore, it supports C-10s argument that its contentions express concern about the lack of representativeness of [LSTP] results for purposes of establishing monitoring, inspection criteria, and inspection intervals. 506 The Board also admitted Contention A, which directly challenged NextEras monitoring program, including its reliance on crack indexing. 507 As the Board explained, [b]ecause NextEra will use an empirical correlation developed in the [LSTP] to correlate the concrete elastic modulus measurements it obtains from core sample testing with the through-thickness expansion to date, the validity of NextEras calculations depends on whether the [LSTP]

specimens were representative of Seabrook concrete. 508 The Board also observed that the LAR justifies a monitoring program based on the CCI and snap ring borehole extensometers because those methodologies were found accurate and reliable in the test program. NextEra justifies its crack width methodology on that basis. 509 The Board further noted that Contention D maintains that the test programs data are not representative of the progression of ASR at 504 CLI-18-4, 87 NRC at 94.

505 C-10 Petition at 9 (quoting Ex. INT019, MPR-4273 at 6-3).

506 [C-10]s Opposition to NextEras Motion in Limine at 6 (May 3, 2019) [hereinafter C-10 Opp.

to NextEra MIL 1].

507 CLI-18-4, 87 NRC at 100-02; LBP-17-7, 86 NRC at 92-102.

508 LBP-17-7, 86 NRC at 100 (citations omitted).

509 Id. (citation omitted).

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Official Use Only Proprietary Information Seabrook. 510 Thus, the Boards ruling on Contention D necessarily implicates the question whether NextEras monitoring program will provide an adequate means of assuring that ASR progression at Seabrook remains within acceptable levels. 511 Because the representativeness of the LSTP concrete is at the crux of Contention D, the mineralogy of the concrete, defined as its chemical 512 and physical properties, 513 is logically enveloped within the basis of that contention and the reformulated contention. 514 Although NextEra argued that it measured representativeness based solely on structural characteristics, 515 we see no such limitation in the scope of Contention D, the other admitted contentions, or the reformulated contention. 516 We admitted testimony and exhibits indicating 510 Id. at 100-01.

511 Id. at 101.

512 Chemical properties refer to the chemical composition and crystalline structure. See Ex.

NER077, NextEra Response to Ex. INT051-R at 4. The chemical properties of particular concern to Dr. Saouma are the reactivity of the aggregate and resulting type of gel. See Ex.

INT051-R, Dr. Saouma Supp. Testimony at 2.

513 The physical properties include shape, hardness, strength, and size distribution of aggregate components. See Ex. NER077, NextEra Response to Ex. INT051-R at 4.

514 We discuss the merits of the argument, below, in Part VIII.A.2.d. C-10 argued that the type of aggregate is important in determining representativeness in its original Petition. C-10 Petition at 9 (NextEra must also systematically evaluate the concrete via petrography and physical testing of cores, and evaluate the expansive capacity of ASR based on ASTM standard tests as promulgated by ASTM Committee C-9 on Concrete and Aggregates[.]).

515 NextEras Proposed Findings of Fact and Conclusions of Law at 54-55; Ex. NER001, MPR Testimony at 21 ([T]he FSEL testing were structurally representative of concrete used in constructing Seabrook structures.); id. at 135-36; see also Ex. INT019, MPR-4273 at 2-6 to -7; Ex. NER077, NextEra Response to Ex. INT051-R at 5-7; Ex. NRC091, Staff Response to Ex.

INT051-R at 3 (listing several characteristics NextEra used to determine representativeness).

516 See LBP-17-7, 86 NRC at 113-14 (quoting Ex. INT019, MPR-4273 at 6-3); C-10 Petition at 11 ([T]he [LSTP] data cannot, in any meaningful way, stand in for or represent the current state of in-situ concrete at the Seabrook reactor[.]).

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Official Use Only Proprietary Information that the mineralogy affects the rate of ASR expansion, 517 the timing of ASR reactions, 518 the type of ASR gel, 519 the pattern of ASR cracking, 520 and the use of CCI. 521 Indeed, NextEra acknowledged that the aggregate size impacts structural capacity, 522 and that particular chemical characteristics of ASR may affect the expansion rate and cracking pattern. 523 Further, the connection between mineralogy and the use of CCI supports our finding that mineralogy is within the scope. 524 Our holding aligns with Commission precedent because the reformulated contention is not being changed or impermissibly stretched. 525 Rather, C-10 is supporting its existing arguments regarding the lack of concrete representativeness and its implications for NextEras reliance on CCI and elastic modulus correlation to monitor expansion.

Nevertheless, NextEra claimed that the reformulated contention is limited to a narrow list of differences between the LSTP specimens and the Seabrook structures: age; length of time 517 Ex. NER012, The Institution of Structural Engineers, Structural Effects of Alkali-Silica Reaction (July 1992) at 10 [hereinafter Ex. NER012, ISE Structural Effects of [ASR)) (non-public); see Ex. NRC091, Staff Response to Ex. INT051-R at 5.

518 Ex. INT035, T. Katayama, An Attempt to Estimate Past Expansion of Concrete Based on Petrographic Stage of Alkali-Silica Reaction, Proc. 39th International Conference on Cement Microscopy, Canada, pp. 217-236 (2017) [hereinafter Ex. INT035, T. Katayama] (non-public).

519 Tr. at 981-82 (Saouma); Ex. NER012, ISE Structural Effects of [ASR] at 11 (non-public).

520 Tr. at 981-82, 1001-02, 1082-83 (Saouma); Ex. INT001-R, Dr. Saouma Pre-Filed Testimony at 11 (non-public); Ex. INT027, Dr. Saouma Pre-Filed Testimony at 11; see Ex.

INT040, P. Rivard and G. Ballivy, Assessment of the expansion related to alkali-silica reaction by the Damage Rating Index Method, 19 Construction and Building Materials 83 (2005) at 89

[hereinafter Ex. INT040, Assessment of ASR Using DRI] (non-public).

521 Ex. INT001-R, Dr. Saouma Pre-Filed Testimony at 11 (non-public); Ex. INT027, Dr. Saouma Pre-Filed Testimony at 11 522 Ex. NER077, NextEra Response to Ex. INT051-R at 3 (The size of aggregate and the surface roughness (i.e., angular surfaces from crushing the rocks rather than smooth surfaces) can both affect the aggregate interlock mechanism for developing shear strength (i.e.,

capacity).).

523 Id. at 4-6.

524 LBP-17-7, 86 NRC at 95-96.

525 McGuire, CLI-02-28, 56 NRC at 386.

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Official Use Only Proprietary Information ASR has propagated; exposure to fresh water at various levels; exposure to salt in the water at different levels and concentrations; the effects of heat; and the effects of radiation. 526 While we agree the preceding factors are some of the bases of Contention D, it is not an exhaustive list.

The sentence in the C-10 Petition from which this list is derived ends with the word etc.,

confirming that it was not intended to be a complete list of C-10s concerns, but rather a list of examples. 527 In addition, as further elaborated below, each of these bases is a topic encompassed within the envelope of concrete mineralogy.

In our ruling on contention admissibility, we found that C-10 had provided sufficient factual support for those listed bases to demonstrate a genuine dispute with the LAR. 528 There, we concluded that Contention D was admissible as to the question of representativeness of the test program. 529 We expressly declined to incorporate the list of bases cited in the Petition into the text of the reformulated contention. 530 Rather, we admitted a contention, not its bases. 531 Therefore, contrary to NextEras argument, we did not identify an exhaustive list of possible bases. 532 As noted, information offered in evidence, even if not specifically stated in the 526 NextEra MIL 2 at 15 (citing CLI-18-4, 87 NRC at 104).

527 C-10 Petition at 11 (Furthermore, the concrete walls of Seabrook, sitting in a salt marsh on the New Hampshire coast, present far too many variables to allow even a well-performed set of tests (as the [LSTP] tests obviously were) in Texas to reflect their characteristics: their age; the length of time ASR has propagated; the effect of the fresh water at varying levels; the effect of the salt in the water at varying levels of height and concentration; the effects of heat; the effects of radiation on certain vital structures; etc.).

528 LBP-17-7, 86 NRC at 113.

529 CLI-18-4, 87 NRC at 104.

530 LBP-17-7, 86 NRC at 127.

531 10 C.F.R. § 2.309(a); see Tenn. Valley Auth. (Watts Bar Nuclear Plant, Unit 2), LBP-09-26, 70 NRC 939, 988 (2009).

532 La. Energy Servs., CLI-04-35, 60 NRC at 623.

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Official Use Only Proprietary Information original contention and bases[, may] be relevant if it falls within the envelope, reach, or focus of the contention when read with the original bases offered for it. 533 Furthermore, although we reject NextEras overly narrow list of exclusive bases of the reformulated contention, concrete mineralogy actually permeates each of those bases. For instance, the mineralogy of the aggregate affects the length of time ASR has propagated, which NextEra acknowledged as one of the originally stated bases of the reformulated contention. 534 One of the main reasons Seabrook concrete is susceptible to ASR and initially escaped detection is due to slowly reactive aggregate, which was not captured by a flawed American Society of Testing and Materials (ASTM) reactivity test. 535 Therefore, the mineralogy of Seabrook concrete, which is slowly reactive, resulted in ASR occurring later on in the plant, affecting the overall length of time ASR has propagated at Seabrook. 536 C-10 raised concerns regarding the effect of radiation on the reactivity of Seabrook concrete. 537 At its core, the reactivity of ASR depends on concrete mineralogy. 538 As acknowledged by all parties, aggregate coarseness has a substantial impact on the rate of ASR expansion. 539 In its Petition, C-10 stated that radiation can potentially accelerate ASR activity 533 Catawba, LBP-04-12, 59 NRC at 391.

534 NextEra MIL 2 at 15 (citing CLI-18-4, 87 NRC at 104).

535 Tr. at 402 (Bayrak); Ex. NRC001-R, Staff Testimony at 9-10.

536 The length of time ASR has propagated and age of the concrete are both representativeness concerns regarding temporality; thus, this conclusion stretches to two original bases. See Ex. INT027, Dr. Saouma Pre-Filed Testimony at 5 (The kinetics of the

[ASR] reaction (that is the rate of expansion) is a function of time, temperature and concrete relative humidity.).

537 C-10 Petition at 10.

538 Ex. NER012, ISE Structural Effects of [ASR] at 10-11 (non-public).

539 See Ex. INT001-R, Dr. Saouma Pre-Filed Testimony at 6, 11 (non-public); Ex. INT027, Dr.

Saouma Pre-Filed Testimony at 6, 11; Ex. NER022-R, MPR-4262 at K-5 (non-public); Ex.

NRC001-R, Staff Testimony at 9-10, 50-51, 62; Tr. at 633 (Simons).

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Official Use Only Proprietary Information or cause ASR to occur with aggregates that are not normally reactive. 540 Therefore, reactivity, which is encompassed within the broader concerns of mineralogy, was raised in the Petition and is within the scope of the reformulated contention.

Furthermore, the remaining bases cited in C-10s Petition generally relate to the effects of heat, water, and humidity on the reactivity of ASR, whose impacts vary depending on the mineralogy. 541 These three subjects permeate many of C-10s concerns about ASR at Seabrook. While the semantics of C-10s arguments have progressed, many of Dr. Saoumas arguments are rooted in these areas. 542 For example, Dr. Saouma (1) stated NextEras use of CCI fails to capture internal relative humidity; 543 (2) emphasized humidity and time as key drivers of ASR; 544 (3) stated salt may corrode steel rebar if it travels through ASR cracks; 545 (4) noted ASR expansions depends on temperature, among other factors; 546 and (5) suggested water below ground increases the internal relative humidity. 547 These arguments stem from the Petition even though they are not stated in the same terms, relate to ASR reactivity, and fall under the reach of concerns regarding concrete mineralogy.

540 C-10 Petition at 10 (quoting RES, NUREG/CR-7171, A Review of the Effects of Radiation on Microstructure and Properties of Concretes Used in Nuclear Power Plants, at 88-89 (Nov.

2013) (ADAMS Accession No. ML13325B077)).

541 The bases discussed in this paragraph are the effect of the fresh water at varying levels; the effect of the salt in the water at varying levels of height and concentration; the effects of heat.

C-10 Petition at 11.

542 See Ex. INT027, Dr. Saouma Pre-Filed Testimony at 20 (ASR proceeds more rapidly in hot and moist conditions. (quoting Ex. INT019, MPR-4273 at 4-8)).

543 Ex. INT032, Dr. Saouma Rebuttal Testimony at 12 (Relative humidity/temperature is a driver of the ASR reaction (if over 80%) or an impediment (if below 80%). This has an influence on CI readings . . . NextEra does not account for it in the field measurement of the CI or the subsequent finite element analysis.); id. at 21-24; Ex. INT028, Dr. Saouma Rebuttal Testimony at 21-24 (non-public).

544 See Ex. INT027, Dr. Saouma Pre-Filed Testimony at 5.

545 Id. at 22; Ex. INT032, Dr. Saouma Rebuttal Testimony at 36.

546 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 5-6, 11-13, 21-22, 33.

547 Id. at 21-22, 26, 33.

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Official Use Only Proprietary Information We also note that one component of mineralogy, the resulting type of ASR gel, was a topic initially raised by Dr. Paul Brown, the original expert cited in C-10s Petition. Specifically, Dr. Brown criticized NextEra for exhibiting a fundamental misunderstanding of ASR kinetics, stating NextEra failed to consider that the ratio of ASR gel in a structure affects the stress on the surrounding concrete. 548 Therefore, mineralogy, which determines the viscosity of ASR gel, 549 was an issue raised at the outset of this proceeding and is within the scope of the reformulated contention.

We therefore deny NextEras Motion in Limine as it pertains to the physical and chemical properties of concrete.

b. C-10s Prima Facie Case For the test specimens used in the LSTP, NextEra obtained half of the coarse aggregate from a quarry in Maine and the other half from a quarry in New Mexico. 550 NextEra intentionally chose highly reactive coarse aggregate from the quarry in New Mexico to accelerate ASR expansion. 551 To justify that choice, NextEra witnesses stated that chemical mineralogy is not critical to representativeness. 552 It argued that even if an exact replication of Seabrooks concrete were possible, ASR expansion would not occur in a reasonable time frame to gather 548 C-10 Petition at 5 (quoting P.W. Brown, Commentary on Seabrook Station License Amendment Request 16-03 at 3 (Sept. 30, 2016) (ADAMS Accession No. ML16306A248)

(ASR gel is not a compound of fixed composition. It has a variable monovalent cation-to-calcium ratio and a compositionally dependent viscosity. A high ratio produces a gel which is fluid and will accommodate to the pores and voids. As this ratio decreases the gel becomes sufficiently viscous that osmotic effects can place stress on the surrounding concrete. A local source of restraint can, for some period of time, minimize dimensional instability and cracking.

However, restraint does not stop the progress of the reaction.)).

549 Ex. NER012, ISE Structural Effects of [ASR] at 11 (non-public).

550 Tr. at 633 (Simons).

551 Id.

552 Ex. NER001, MPR Testimony at 82-83; Tr. at 642 (Bayrak) ([W]ere not aiming to model the chemical reaction. This was never an intent.).

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Official Use Only Proprietary Information probative data. 553 In accordance with industry practice, the concrete was doped with to accelerate the expansion further. 554 By the time of the testing, the chemical composition of the LSTP concrete differed greatly from the concrete at Seabrook. 555 NextEra determined that Seabrook concrete components matched as closely as reasonably achievable. 556 In developing the test specimens, NextEra identified characteristics of concrete components deemed critical to structural capacity. 557 For example, NextEra recognized the size and roughness of coarse aggregate was a crucial component because both can affect the aggregate interlock mechanism for developing shear strength, which, in turn, can affect a components structural capacity. 558 Dr. Saouma agreed that there is a very strong similarity in the gradation between the aggregates used in the test specimens and the gradation of the Seabrook aggregates. 559 But Dr. Saouma stated that it is also essential to have a mineralogic comparison of the aggregates. 560 As noted above, ASR is a chemical reaction that produces an alkali-silicate gel that expands as it absorbs moisture. 561 The expansion exerts stress on the surrounding concrete and results in cracking. 562 According to Dr. Saouma, [d]ifferent kinds of reactive 553 NextEras Proposed Findings of Fact and Conclusions of Law at 54.

554 See Ex. INT027, Dr. Saouma Pre-Filed Testimony at 11; Ex. NER022-R, MPR-4262 at 3-2, 4-7, 4-11 (non-public).

555 Ex. NER022-R, MPR-4262 at 4-7, 4-11 (non-public).

556 See Ex. NRC091, Staff Response to Ex. INT051-R at 3.

557 Ex. NER077, NextEra Response to Ex. INT051-R at 3.

558 Id.

559 Tr. at 1074 (Saouma).

560 Tr. at 1082-83 (Saouma); Ex. INT051-R, Dr. Saouma Supp. Testimony at 1-2.

561 See supra note 423 and accompanying text.

562 Ex. INT010, Original LAR at PDF 9.

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Official Use Only Proprietary Information aggregates or sand will cause different types of gel. The calcium content of the gel . . . is known to be critical in characterizing the ASR expansion. 563 As C-10 acknowledged, Dr. Saouma did not claim that the chemical characteristics of aggregates and the associated ASR gel are relevant to structural capacity. 564 But C-10 relied on his testimony to support its claim that the comparative chemical characteristics of the aggregates and gels in Seabrook concrete and LSTP specimens are relevant to (1) NextEras program for monitoring ASR development through crack indexing; and (2) its use of the correlation method to determine past expansion. 565 Dr. Saouma testified that it is necessary to have a comparison of the mineralogy of the aggregate at Seabrook and the mineralogy of the aggregate used in the LSTP because mineralogy plays an important role in the formation of ASR, in the formation of the gel, in the type of gel, in the nature of the expansion, [and] in the type of cracks that we expect. 566 Dr.

Saouma testified that reactive sand was the driving force for ASR expansion in the LSTP, whereas at Seabrook, the driving force is the coarse aggregates; therefore, the cracking pattern is likely to be entirely different. 567 [S]and will result in a rapid expansion, and aggregates will cause a slower, but larger, future expansion. 568 NextEra witness Dr. Bayrak confirmed the presence of highly reactive sand in the LSTP specimens. 569 In Dr. Saoumas opinion, because the chemical composition of the concrete in the LSTP specimens differed greatly from the concrete at Seabrook, one could not use the cracking pattern or the expansion rates to be 563 Ex. INT031, Dr. Saouma Review of Selected Documents at 3.

564 C-10s Redacted Supp. Proposed Findings of Fact and Conclusions of Law at 2.

565 Id. at 3.

566 Tr. at 1082-83 (Saouma).

567 Tr. at 424-26, 604, 981-82, 1001-02 (Saouma).

568 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 6.

569 Tr. at 985 (Bayrak).

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Official Use Only Proprietary Information indicative of what would happen at Seabrook. 570 He testified that the differences between LSTP and Seabrook concrete will impact the ability to correlate crack widths, expansions, combined crack indexing (CCIs), and crack patterns with Seabrook. 571 Several reports in the record support Dr. Saoumas opinion. He cited the work of Poyet, et al., confirming that fine aggregates (sand) will yield a faster reaction . . . than coarse ones.

However, the coarse aggregates will ultimately yield larger expansion than the one caused by the sand. 572 Also, according to the Institution of Structural Engineers (ISE), the type, particle size and proportion of silica in the aggregate will influence the rate and severity of the reactivity of the concrete. 573 The ISE document further explains that:

The characteristics of the alkali-silica gel formed by the [ASR] reaction vary with its chemical composition, temperature, moisture content and pressure. Its consistency can range from that of heavy engine oil to that of polyethylene.

Some aggregates, e.g. Danish flints, Beltane opal, generate sufficient quantities of gel for it to exude from cracks. Conversely, in most UK cases of ASR, gel is visible only when cores are petrographically examined. 574 A study by Tetsuya Katayama concerning concrete expansion also supports Dr. Saoumas opinion that variations in mineralogy affect reaction vigor, reaction timing, and crack width. 575 In addition, Dr. Saouma questioned the representativeness of the LSTP specimens because they were essentially stored in a greenhouse, under very hot and very humid conditions that are not conducive to the drying of the [concrete] surface. 576 By contrast, Seabrook has lower relative humidity, and [o]n most of the surface dry shrinkage has occurred 570 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 11.

571 Id.

572 Id. (citing Ex. INT034, Poyet et al. at 229 (non-public)).

573 Ex. NER012, ISE Structural Effects of [ASR] at 10 (non-public).

574 Id. at 11 (non-public).

575 See Ex. INT035, T. Katayama.

576 Tr. at 475-76 (Saouma).

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Official Use Only Proprietary Information and the first couple of inches have a lower relative humidity. 577 The rate of ASR expansion is a function of time, temperature[,] and concrete relative humidity. 578 The conditions at Seabrook are quite different from the conditions at the LSTP site in Texas. 579 In New Hampshire, the temperature is much lower on the surface of a concrete wall, and there is a thermal gradient with much warmer concrete and greater relative humidity inside. 580 Thus, Dr. Saouma testified that conditions during the LSTP were much more conducive to the formation of ASR cracks at the concrete surface than are conditions at Seabrook. 581 Because of the lower relative humidity at the surface, Seabrook structures may show little or no surface cracking but may have significant interior cracking, where the relative humidity is at or above the 80% threshold necessary for ASR reactivity. 582 The relative humidity gradient postulated by Dr. Saouma finds some support in a study of ASR in five dams in the southwestern United States. 583 The report, conducted jointly by a private company and the Department of the Interiors Bureau of Reclamation, found that in three of the dams, [m]ost of the concrete . . . still appears to contain enough moisture to permit expansion from [ASR]. 584 Yet, concrete within several inches of exposed surfaces [wa]s sufficiently dry to preclude expansion. 585 577 Tr. at 476 (Saouma).

578 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 5.

579 Id. at 20-21.

580 Id.

581 Tr. at 490-94 (Saouma).

582 Id.; Ex. INT007, Dr. Saouma Review of Selected Documents at 8 (non-public); Ex. INT031, Dr. Saouma Review of Selected Documents at 9; Ex. INT028, Dr. Saouma Rebuttal Testimony at 21-25 (non-public); Ex. INT032, Dr. Saouma Rebuttal Testimony at 21-25.

583 See Ex. INT037, Stark, D., & De Puy, G. W. (1987). Alkali-silica reaction in five dams in southwestern United States. ACI Special Publication, 100, 1759-1786 (non-public).

584 Id. at 1761 (non-public).

585 Id. (non-public).

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Official Use Only Proprietary Information After the evidentiary hearing, NextEra produced the Santa Ana Aggregates document, as directed by the Board in the Order granting C-10s Motion to Compel. 586 In his supplemental written testimony concerning that document, Dr. Saouma stated that it lack[ed] a direct mineralogical comparison (both physical and chemical) between the test aggregate (and sand) and the aggregate (and sand) used in [the] Seabrook structures. 587 He further explained that he has not found such a mineralogical comparison in any of the other documents that NextEra has identified as having information about the petrographic characteristics of Seabrook and LSTP test specimen aggregates. 588 Moreover, Dr. Saouma stated that the document failed to specify whether the Santa Ana aggregate was used in the LSTP, or whether it was merely sampled. 589 He concluded that NextEra has not provided enough information to allow a comparison between the mineralogy of Seabrook concrete and LSTP test specimens, and consequentially the concrete is not proven to be sufficiently representative. 590 Dr. Saoumas opinion, together with the reports he cited in support of his opinion, are sufficient to meet C-10s burden to establish a prima facie case that the LSTP concrete is not sufficiently representative of Seabrook concrete to support NextEras CCI methodology. The burden of proof on that issue therefore shifts to NextEra. 591 C-10 also argued that the lack of data on the comparative chemical characteristics of the aggregates and gels in Seabrook concrete and LSTP test specimens undermines the reliability of the elastic modulus correlation used to determine past expansion. 592 As explained above, to 586 See supra Part II.F.

587 See Ex. INT051-R, Dr. Saouma Supp. Testimony at 1.

588 Id. at 2.

589 Id. at 1.

590 Id. at 2.

591 See supra Part III.B.1.

592 C-10s Redacted Supp. Proposed Findings of Fact and Conclusions of Law at 3.

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Official Use Only Proprietary Information determine the ASR-induced expansion before extensometer installation, NextEra uses an empirical correlation developed in the LSTP to correlate elastic modulus measurements with the through-thickness expansion to the date of the installation. 593 The accuracy of that correlation is essential to determining total expansion and thus verifying regulatory compliance. 594 C-10 has not cited any testimony or other evidence, however, sufficient to make a prima facie case on this claim. Dr. Saouma did testify that differences in aggregate chemistry may affect crack width, cracking patterns, and expansion rates. 595 However, he did not provide any evidence that aggregate chemistry will change the correlation between reduced elastic modulus and past expansion. We therefore will not consider further the claim that the comparative chemical characteristics of the aggregates and gels in Seabrook concrete and LSTP test specimens undermine the reliability of the elastic modulus correlation.

c. NextEra and Staff Responses NextEra expert witness Dr. Bayrak confirmed the use of different aggregate in the LSTP concrete. 596 NextEra argued, however, that the composition was similar to Seabrook. 597 The Staff agreed with NextEra and argued the LSTP is sufficiently representative even if the coarse aggregate is not identical. 598 The Staff reviewed each component of the LSTP, finding each to be representative and/or bounding of the concrete at Seabrook. 599 The Staff found that the test specimens reflected the typical characteristics of ASR-affected structures at Seabrook[,] such 593 See supra notes 476-479 and accompanying text.

594 See infra Part VIII.D.

595 Tr. at 981-82, 1001-02, 1082-83 (Saouma); Ex. INT032, Dr. Saouma Rebuttal Testimony at 12.

596 Tr. at 985 (Bayrak).

597 Tr. at 633-34 (Simons) (stating SGH sent the blend of aggregate to an expert petrographer who confirmed its similarity to the plant).

598 NRC Staff SOP at 32-33.

599 Id. at 33.

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Official Use Only Proprietary Information as utilizing a similar scale and structural context and similar reinforcement ratios and configurations. 600 The Staff also determined the concrete of the test specimens reasonably reflected the properties of the concrete in Seabrook structures. 601 NextEra maintained that it provided sufficient information to permit an adequate mineralogical comparison of the LSTP aggregate and the Seabrook aggregate. 602 Several of the documents it cited, however, while apparently produced during the mandatory disclosure process, were not entered into evidence. 603 We may not base our ruling on documents that are not part of the evidentiary record. 604 But we need not determine whether NextEra produced sufficient information to permit a comparison of the chemical characteristics of the LSTP aggregate and the Seabrook aggregate, because NextEra witnesses acknowledged that to achieve bounding levels of ASR expansion in a useful timeframe . . . the LSTP necessarily used a faster-reacting aggregate with similar physical characteristics (i.e., size and surface roughness), but with different chemical characteristics (composition, crystalline structure). 605 Thus, it is undisputed that the Seabrook aggregate and the LSTP aggregate differed in their chemical composition and structure. The question we must resolve is whether those acknowledged differences are important in determining representativeness.

600 Id. at 34.

601 Id. at 35 (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.).

602 See NextEra Motion to Compel Letter at 2; Ex. NER077, NextEra Response to Ex. INT051-R at 7-8.

603 NER077, NextEra Response to Ex. INT051-R at 8 n.29.

604 See 10 C.F.R. § 2.713(c) (An initial decision will . . . be based on the whole record and supported by reliable, probative, and substantial evidence.).

605 Ex. NER077, NextEra Response to Ex. INT051-R at 4 (citations omitted).

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Official Use Only Proprietary Information NextEra witnesses stated that the acknowledged differences are not important. 606 They testified that [t]he LSTP did not include any critical characteristics that pertain to the chemical characteristics of the minerals in the aggregate. 607 They agreed with Dr. Saouma on several key facts . . . including the importance of the crystalline structure of the silica within the aggregate on reactivity, the importance of aggregate chemical characteristics on reaction rate, and the fact that expansion of gel causes cracking. 608 NextEra witnesses also acknowledge[d]

that differences in concrete mixture design may result in ASR gel with different chemical and physical attributes, 609 and that differences in concrete mixture design may affect the typical crack pattern. 610 But they emphasized that NextEras approach is focused on the structural implications of ASR across a wide range of expansion levels and that [t]hese structural implications are not significantly affected by the rate of reaction, characteristics of the gel, or the specific pattern of microcracks comprising a given expansion level. 611 The Staff agreed with NextEra that the differences in concrete between Seabrook and the LSTP specimens are not significant for the purposes of determining representativeness. 612 The Staffs conclusion that the Seabrook ASR expansion monitoring program is acceptable and provides reasonable assurance that Seabrook structures will continue to meet the NRCs requirements 613 remained unchanged after NextEra produced the Santa Ana Aggregates Report.

606 Id.

607 Id.

608 Id. at 5 (citing Ex. NER001, MPR Testimony at 38-39, 45).

609 Id. (citing Ex. NER001, MPR Testimony at 82).

610 Id. (citing Tr. at 603 (Simons)).

611 Id. (emphasis omitted).

612 Ex. NRC091, Staff Response to Ex. INT051-R at 3-4.

613 Id. at 6.

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d. Findings of Fact and Board Analysis As noted above, it is undisputed that the Seabrook aggregate and the LSTP aggregate differed in their chemical composition and structure. Although Dr. Saoumas concerns regarding concrete representativeness do not invalidate the CCI, 614 he has raised significant questions whether the chemical characteristics of the LSTP aggregates and the associated ASR gel was sufficiently representative of Seabrook concrete. In particular, the Board accepts Dr. Saoumas testimony that differences in aggregate chemistry affect crack width, cracking patterns, and expansion rates. 615 The lack of concrete representativeness identified by Dr. Saouma may compromise the reliability of the extensometer threshold for extensometer installation of 1.0 mm/m (0.1%) (the extensometer threshold). Differences in crack width, cracking patterns, and expansion rates imply that monitoring of surface cracking using the CCI may be insufficient to reliably determine when extensometers should be installed to detect significant interior cracking of Seabrook structures. As explained previously, NextEra uses the CCI to monitor the effects of ASR on the surface of Seabrook structures and to determine when to install extensometers to monitor through-thickness expansion. 616 The monitoring methodology is derived from the LSTP. 617 For the LSTP specimens, the rate of expansion was approximately the same in all three directions until expansion reached to mm/m (  % to  %). 618 Thereafter, the LSTP specimens exhibited much greater expansion in the through-thickness direction than the in-plane 614 Tr. at 426 (Saouma).

615 Tr. at 981-82, 1001-02, 1082-83 (Saouma); Ex. INT032, Dr. Saouma Rebuttal Testimony at 12.

616 See supra notes 448-450 and accompanying text.

617 See Ex. NER001, MPR Testimony at 91-92, 122.

618 Ex. NER020, MPR 0326-0062-88, Rev. 2, Initial Expansion Assessment of ASR-Affected Reinforced Concrete Structures at Seabrook Station (Mar. 2018) (FP101070, Rev. 1) at 5

[hereinafter Ex. NER020, MPR 0326-0062-88, Rev. 2] (non-public).

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Official Use Only Proprietary Information directions. 619 These observations led NextEra to conclude that using the CCI to monitor in-plane expansion sufficiently characterizes ASR development until at least 1.0 mm/m (0.1%)

expansion, after which through-thickness monitoring by extensometers is required to monitor further ASR expansion. 620 To ensure that through-thickness expansion will be adequately monitored before the limit is reached, which is critical for the adequate protection of public health and safety, the extensometer threshold must be accurate and reliable. Because the Board questions whether the LSTP specimens were sufficiently representative of Seabrook concrete, 621 we also question NextEras reliance on the LSTP data to justify the 1.0 mm/m (0.1%) extensometer threshold.

Absent a reliable threshold, through-thickness expansion near or even above the expansion limit may occur before the 1.0 mm/m (0.1%) extensometer threshold is reached, and therefore before the installation of extensometers. Thus, significant internal cracking may go undetected. 622 That would compromise the reliability of NextEras structural capacity 619 Id. (non-public). The relationship between the CCI and through-thickness expansion observed in the LSTP specimens is illustrated in figure 4, Ex. NER003, MPR Testimony - - Proprietary Appendix at 5 fig.4 [hereinafter Ex. NER003, MPR Testimony, Proprietary Appendix] (non-public). NextEras monitoring program reflects its determination that Seabrook structures will exhibit a cracking pattern equivalent to that shown in figure 4, and that therefore extensometers need not be installed until in-plane expansion reaches 1.0 mm/m (0.1%). A different cracking pattern, however, could be problematical. If the CCI plateaus below 1.0 mm/m (0.1%), the through-thickness expansion rate is faster than shown in figure 4, or both, significant through-thickness expansion may occur before an extensometer is installed.

620 Ex. INT019, MPR-4273 at B-4; Ex. INT021, MPR-4273 at B-4 (non-public).

621 Ex. INT001-R, Dr. Saouma Pre-Filed Testimony at 8, 9-17 (non-public); Ex. INT027, Dr.

Saouma Pre-Filed Testimony at 8, 9-17; Ex. INT032, Dr. Saouma Rebuttal Testimony at 2.

622 This concern is illustrated in figure B-2, Ex. INT021, MPR-4273 at B-5 fig.B-2 (non-public).

The yellow rectangle, entitled Approaching Expansion Limit Reevaluate Extensometer Threshold, represents possible locations with CCI less than 1.0 mm/m (0.1%) but through-thickness expansion greater than mm/m ( %). Id.; Ex. INT019, MPR-4273 at B-5 fig.B-2.

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Official Use Only Proprietary Information evaluations, which are premised on through-thickness expansion remaining within the limits identified in the LSTP. 623 Therefore, although C-10 agreed that the differing chemical characteristics of the aggregates and the associated ASR gel do not impact structural capacity, 624 the Board finds that those differing characteristics create substantial uncertainty as to whether the LSTP specimens were sufficiently representative of Seabrook concrete that they may serve as the basis of the CCI.

In support of CCI, NextEra and Staff witnesses testified that it is a generally accepted approach for measuring the rate of ASR expansion in concrete structures. 625 We are concerned, however, with the specific question whether the LSTP specimens are sufficiently representative of Seabrook concrete such that the crack widths, cracking patterns, and expansion rates observed in the test specimens justify the conclusion that significant through-thickness expansion will not occur in Seabrook seismic Category I structures as long as the CCI remains below the 1.0 mm/m (0.1%) extensometer threshold. General statements concerning the widespread acceptance of CCI are of little help in resolving that issue.

The Staff concluded that the LSTP was sufficiently representative of the structures at Seabrook, that interior cracking without surface cracking was not observed during the LSTP, and that the LSTP demonstrated that interior and surface cracking advanced together until surface cracking plateaued. 626 To the extent the Staff relied on those conclusions to justify the 623 Ex. INT010, Original LAR at PDF 19-20; Ex. NER001, MPR Testimony at 60.

624 C-10s Redacted Supp. Proposed Findings of Fact and Conclusions of Law at 2.

625 Ex. NRC001-R, Staff Testimony at 62 (citing Ex. NER013, U.S. Department of Transportation, Federal Highway Administration (FHWA), Report on the Diagnosis, Prognosis, and Mitigation of Alkali-Silica Reaction (ASR) in Transportation Structures (FHWA-HIF-09-004)

(Jan. 2010) [hereinafter Ex. NER013, FHWA Report]); see also Tr. at 319-20 (Simons), 323-27, (Bayrak), 482-85 (Bayrak).

626 Tr. at 1132-34 (Buford); NRC Staff SOP at 57-62.

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Official Use Only Proprietary Information 1.0 mm/m (0.1%) extensometer threshold, we are not persuaded. Dr. Saouma has convincingly testified that the acknowledged differences in aggregate chemistry affect crack width, cracking patterns, and expansion rates. For the reasons explained above, those differences cause the Board to question the reliability of the application of the 1.0 mm/m (0.1%) extensometer threshold to Seabrook structures.

Dr. Bayrak testified that more than 200 cores have been taken at Seabrook and there have been zero occurrence[s] of a delamination crack. 627 We understand that the Staff refers to this evidence when it stated that field evidence from cores that were removed at Seabrook in support of the installation of extensometers at both above and below ground locations has not shown any indications of structural concern in the concrete interior. 628 But we do not find evidence regarding the lack of an observed delamination crack to date sufficient to justify the 1.0 mm/m (0.1%) extensometer threshold for extensometer installation. Those are different issues. The concern remains that, because LSTP data was not sufficiently representative of Seabrook concrete, through-thickness cracking approaching the expansion limit may occur even though the extensometer threshold has not been reached.

In Appendix B to MPR-4273 (referred to as Check 3), MPR recommended a monitoring program to check the reliability of the extensometer threshold, albeit for different reasons than those urged by Dr. Saouma. As MPR explained, NextEra has installed several extensometers in locations where in-plane expansion is less than 1.0 mm/m [0.1%]. This provides the opportunity to check consistency of expansion behavior over the entire range exhibited at 627 Tr. at 1097 (Bayrak). Delamination is a crack between . . . two reinforcing mats. Ex.

INT027, Dr. Saouma Pre-Filed Testimony at 17 fig.10. We address the issue of delamination cracks infra Part VIII.E.

628 Ex. NRC001-R, Staff Testimony at 64.

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Official Use Only Proprietary Information Seabrook Station. 629 The Board understands that these are the control extensometers referred to in the SMP. 630 MPR noted that [f]or the [LSTP] specimens, the point at which expansion reoriented primarily in the through-thickness direction varied between specimens, even though the specimens were essentially identical. 631 MPR recognized that [d]ata from Seabrook Station may exhibit further variability from differences in configuration (e.g., wall thickness) and confinement (e.g., from deadweight). 632 The Board finds Check 3 also necessary because Dr.

Saouma has identified another potential source of variability that could also affect the reliability of the extensometer thresholdthe differences in the chemistry of the LSTP concrete and Seabrook concrete that may affect crack width, cracking patterns, and expansion rates.

The Staff made Check 3 a mandatory condition when it granted the license amendment. 633 Pursuant to Check 3, NextEra will:

[P]erform an engineering evaluation if the periodic expansion check identifies either of the following circumstances:

• Any location with CCI less than [1.0] mm/m [0.1%] exhibits through-thickness expansion approaching the test program limit (i.e.,

greater than [ mm/m]  %). Such an observation would challenge the premise that an extensometer is not needed for locations with a CCI of less than [1.0] mm/m [0.1%]. The engineering evaluation would focus on the suitability of this criterion.

• The general trend of expansion behavior at Seabrook Station significantly departs from the expansion behavior of the [LSTP]

specimens. The expected trend at Seabrook Station is that in-plane and through-thickness expansion values will be comparable at lower 629 Ex. INT019, MPR-4273 at B-5; Ex. INT021, MPR-4273 at B-5 (non-public).

630 Ex. NER007, Seabrook [SMP] Manual Rev. 7, app. B, tbl.2. See Ex. NER001, MPR testimony at 150 (stating that extensometers were also installed in ten locations with ASR-induced expansion less than 1.0 mm/m (0.1%)).

631 Ex. INT019, MPR-4273 at B-5; Ex. INT021, MPR-4273 at B-5 (non-public).

632 Ex. INT019, MPR-4273 at B-5; Ex. INT021, MPR-4273 at B-5 (non-public).

633 See Ex. INT024, Final SE at PDF 67-69.

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Official Use Only Proprietary Information expansion levels and eventually transition to predominately through-thickness expansion. 634 Check 3 will help resolve the Boards concern that the 1.0 mm/m (0.1%) extensometer threshold may not provide reasonable assurance of adequate protection of public health and safety. Nevertheless, we have identified a significant problem with the schedule for monitoring the control extensometers. Extensometers in Tier 3 areas, those locations where the 1.0 mm/m (0.1%) extensometer threshold has been exceeded, are to be monitored every six months. 635 But the extensometers installed where in-plane expansion is less than 1.0 mm/m (0.1%) (i.e.,

the control extensometers) will only be monitored for through-thickness expansion in 2025 and every ten years thereafter. 636 This schedule fails to provide adequate protection of public health and safety. As noted, one purpose of Check 3 is to determine whether the extensometer threshold of 1.0 mm/m (0.1%) will assure that extensometers will be installed before through-thickness expansion approaches the expansion limit. As Check 3 explains, the observation of an area with a CCI less than 1.0 mm/m (0.1%) that exhibits through-thickness expansion approaching the expansion limit would challenge the premise that an extensometer is not needed for locations with a CCI of less than [1.0] mm/m [0.1%]. 637 That premise is fundamental to NextEras monitoring program, and if it is incorrect, potentially damaging ASR expansion could go undetected for years.

There is no apparent reason why NextEra should not monitor the control extensometers every six months. The burden of doing so is not significant, given that monitoring only requires 634 Ex. INT019, MPR-4273 at B-5 to -6; Ex. INT021, MPR-4273 at B-5 to -6 (non-public).

635 See Ex. INT010, Original LAR at PDF 65.

636 Ex. NER007, Seabrook [SMP] Manual Rev. 7 at 3-1.7 to -1.8 (non-public); Ex. NER001, MPR Testimony at 62; Ex. INT019, MPR-4273 at B-5; Ex. INT021, MPR-4273 at B-5 (non-public). NextEra conducts in-plane monitoring of ASR expansion every thirty months for structures with less than 1.0 mm/m (0.1%) of ASR expansion. Ex. INT010, Original LAR at PDF 33 tbl.5.

637 Ex. INT019, MPR-4273 at B-5 to -6; Ex. INT021, MPR-4273 at B-5 to -6 (non-public).

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Official Use Only Proprietary Information extensometer removal, measurement, and replacement. NextEra already monitors numerous extensometers in the Tier 3 areas every six months. 638 Monitoring the control extensometers every six months should ensure the prompt detection of any observation that would challenge the criterion (i.e., the threshold) for extensometer installation. In the event of such an observation, Check 3 requires NextEra to perform an engineering evaluation focusing on the continued suitability of that criterion. 639 The Board therefore modifies Check 3 as follows:

NextEra shall undertake the monitoring required by MPR-4273, Appendix B, Check 3, for control extensometers every six months, rather than in 2025 and every ten years thereafter.

The Board concludes that its modification of the Check 3 monitoring condition is necessary to provide reasonable assurance. With that modification, NextEras CCI methodology satisfies the reasonable assurance standard despite the acknowledged differences in the chemical characteristics of the LSTP aggregate and the Seabrook aggregate.

One issue remains regarding the CCI. Dr. Saouma testified that NextEra should have only used crack width indexing in conjunction with advanced petrography. 640 He relied on the FHWA Guideline, which recommends a combination of crack width indexing and petrography for the preliminary investigative stage of an ASR assessment program and encourages its use during the later detailed study stage. 641 NextEra did perform crack width indexing and petrography during its preliminary investigation. 642 We agree with NextEra that for the purpose 638 See Ex. NER007, Seabrook [SMP] Manual Rev. at B-12 to -16 tbl.2 (non-public).

639 Ex. INT019, MPR-4273 at B-4 to -6; Ex. INT021, MPR-4273 at B-4 to -6 (non-public).

640 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 20.

641 Id.; see Ex. NER013, FHWA Report at 3-6.

642 Ex. NER004, SGH Testimony at 32, 35-36 (citing Ex. NER028, SG&H Report 110594-RPT-02, Rev. 1, Damage Rating Index and ASR Rating (Feb. 10, 2012) (FP100702)).

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Official Use Only Proprietary Information of determining whether surface cracking has reached the threshold for extensometer threshold, further petrography is not required because NextEra assumes that all cracking at Seabrook is caused by ASR unless proven otherwise. 643 We address the separate question whether petrography should be required for cores removed from Seabrook concrete infra Part VIII.E.

3. Test Specimen Scaling, Reinforcement, and Size

a. Motion in Limine We find that discussion regarding the scaling of LSTP test specimens is fairly encompassed by the description of the admissible contentions that C-10 outlined in its petition. 644 Accordingly, NextEras second Motion in Limine is denied in this respect. 645 We find section C.2.2 of Dr. Saoumas pre-filed testimony, 646 and all testimony related to prototype scaling, including specimen dimensions, loads, and boundary conditions within the scope of the reformulated contention. 647 Stated briefly, Dr. Saouma testified that there is a significant problem with the scaling of LSTP test specimens, such that representativeness is jeopardized. 648 Dr. Saouma stated that

[a] significant problem with the [LSTP] testing is the failure to ensure that the relative 643 Ex. NER001, MPR Testimony at 151-52.

644 Pilgrim, CLI-10-11, 71 NRC at 310.

645 In NextEras second Motion in Limine, it refers to Dr. Saoumas arguments as those pertaining to scaled prototype specimens. See NextEra MIL 2 at 15, 17. However, the specific section of Dr. Saoumas Pre-Filed Testimony is titled, Specimen dimensions, loads and boundary conditions. See Ex. INT027, Dr. Saouma Pre-Filed Testimony § C.2.2. Section C.2.2 of Dr. Saoumas Pre-Filed Testimony includes § C.2.2.2, which is titled Boundary Conditions. Id. at 12-13. In this Initial Decision, we address all motion in limine issues relating to boundary conditions in this section and the following section. We address boundary conditions on the merits in the next section.

646 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 11-13.

647 This includes: Ex. INT027, Dr. Saouma Pre-Filed Testimony §§ C.2.2, C.2.2.2; Ex. INT028, Dr. Saouma Rebuttal Testimony §§ D.3.2, D.4.1, D.4.2 (non-public); Ex. INT032, Dr. Saouma Rebuttal Testimony §§ D.3.2, D.4.1, D.4.2.

648 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 11-12.

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Official Use Only Proprietary Information dimensions of the concrete beam that was tested were scaled to the prototype (i.e., the Seabrook reactor). 649 Consequently, the corresponding load will not be representative. 650 Dr.

Saouma testified that the LSTP failed to account for boundary conditions. 651 Specifically, he claimed that [i]n a test, the model must be subjected to the same conditions (support, restraints and load) as the prototype (Seabrook). 652 Dr. Saouma also testified that the failure to model both in-plane and out-of-plane shear, in addition to the lack of proper scaling and boundary conditions, renders the LSTP not representative. 653 NextEra asserted that Dr. Saoumas testimony as related to scaled prototype specimens attempts to shift the focus of the reformulated contention to an entirely new set of bases that could have been, but were not, raised at the outset of this proceeding. 654 It claimed that Dr.

Saoumas concerns regarding scaled prototype specimens were not raised in C-10s Petition, and as a result, constitute new arguments. 655 649 Id. at 11. Dr. Saouma explained that [b]efore testing a model, one must first determine the largest dimension that can be accommodated in the laboratory (say x inches), and then determine the corresponding one in the prototype (in this case Seabrook) (most likely the thickness of the wall, say y inches) Then one would determine the scaling parameter alpha by taking the ratio of the two (y divided by x). This ratio should be respected in all other dimensional quantities (especially reinforcement location and ratios) for a correctly designed test. And the ratio will in turn govern the location of the reinforcement and the diameter of the reinforcement. Id. at 11-12.

650 Id. at 12.

651 Id. at 12-13.

652 Id. at 12.

653 Id.

654 NextEra MIL 2 at 15-17.

655 Id.

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Official Use Only Proprietary Information C-10 maintained that Dr. Saoumas arguments are properly before the Board 656 and that virtually every aspect of Dr. Saoumas testimony relates to the question whether the LSTP is representative of the progress of ASR at Seabrook over time. 657 We first address NextEras claims that Dr. Saoumas arguments are new and not part of the original list of bases. As stated above, supra Part VIII.A.2.a, we decline to take such a narrow view of the bases of the reformulated contention. Rather than introducing a new series of claims, we find that Dr. Saoumas explanations clarify issues identified in C-10s Petition and amplified in its Reply to the Staff. 658 In its Reply, C-10 queried whether achieving the goal of obtaining representativeness would have been better served had NextEra removed choice sections from the ASR-affected concrete in the unused Unit 2 at Seabrook Station[.] 659 We find this argument sufficient to suggest that C-10 was concerned that the size, dimensions, and boundary conditions of the test specimens did not match Seabrook structures.

Representativeness is the crux of Contention D and, ultimately, of the reformulated contention. As explained in further detail, supra Part II.B, these material disputes challenge the adequacy of the LARs monitoring program, acceptance criteria, and inspection intervals.

NextEra asserted that the reformulated contention is limited to a narrow list of differences between the LSTP and the Seabrook structures. 660 Although we agree that these factors constitute some of the bases that form Contention D, as more fully explained above, they by no 656 See C-10 Opp. to MIL 2.

657 Id. at 11-13.

658 See La. Energy Servs., CLI-04-25, 60 NRC at 224 (approving licensing boards decision to consider information in petitioners reply briefs that legitimately amplified issues presented in the initial petitions).

659 C-10s Reply at 4.

660 See NextEra MIL 2 at 2-3. Chief among those, age, and the length of time ASR has propagated. C-10 Petition at 11.

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Official Use Only Proprietary Information means represent an exhaustive list. 661 Accordingly, we find that C-10s testimony on prototype scaling supports its existing arguments regarding the lack of representativeness and its implications for the LSTP. 662 In our ruling on contention admissibility, we concluded that Contention D was admissible as to the question of [the] representativeness of the [LSTP]. 663 NextEra witnesses explained that one of the primary reasons necessitating the use of the LSTP was that published test results for selected limit states were from specimens that were too small to be considered representative. 664 Further, NextEra witnesses stated that the LSTP was conducted to obtain more representative data than was available in public literature. 665 Because scaling was a key parameter of representativeness, and a primary factor in initially conducting an LSTP, there clearly is a connection between scaling and representativeness.

Dr. Saouma alleged multiple errors in the design of the LSTP. 666 These errors relate to specimen dimensions, loads, and boundary conditions in the scaled prototype. 667 We find NextEras assertion that Dr. Saoumas testimony falls outside the scope of issues 661 See supra Part VIII.A.2.a.

662 See La. Energy Servs., CLI-04-35, 60 NRC at 623.

663 CLI-18-4, 87 NRC at 104 (citing LBP-17-7, 86 NRC at 114).

664 Ex. NER001, MPR Testimony at 138 (A detailed comparison of the test specimens to the reference location is included in [Ex. NER026,] MPR-3757[.]).

665 Id. at 54-55.

666 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 11-13.

667 Id.

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Official Use Only Proprietary Information unpersuasive. 668 The issue of prototype specimen scaling is covered within the bases 669 of Contention D and the reformulated contention. 670 Therefore, NextEras Motion in Limine, with regards to prototype scaling, specimen dimensions, loads, and boundary conditions, is denied.

b. C-10s Prima Facie Case Dr. Saouma identified the scaling of LSTP test specimens as a significant problem with

[the LSTP] insofar as it jeopardized representativeness. 671 Specifically, Dr. Saouma stated that a proper scaling ratio should be respected in all . . . dimensional quantities (especially reinforcement location and ratios)[.] 672 If the test specimens are not scaled properly, Dr.

Saouma stated, the specimens may exhibit an erroneous failure mechanism (a beam may fail by bending, or a combination of bending and shear; the degree of which depends on the relative dimensions and location of shear reinforcement). Under these conditions, the corresponding load will not be representative. 673 Dr. Saouma testified that his major concern is the Containment Enclosure Building (CEB). 674 The CEB is located outside the Containment Building and has a similar geometry. 675 668 NextEra MIL 2 at 15-17.

669 La. Energy Servs., CLI-04-35, 60 NRC at 623 (Under our contention rule, [petitioners] are not being asked to prove their case, or to provide an exhaustive list of possible bases, but simply to provide sufficient alleged factual or legal bases to support the contention, and to do so at the outset.).

670 See LBP-17-7, 86 NRC at 112-21, 125-27.

671 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 11.

672 Id. at 11-12.

673 Id. at 12.

674 Tr. at 612-13 (Saouma).

675 Ex. NRC007, UFSAR §§ 3.8.1.1, 3.8.4.

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Official Use Only Proprietary Information This structure provides leak protection for the containment and protects it from certain loads. 676 The UFSAR described the CEB:

The [CEB] is a reinforced concrete . . . cylindrical structure with a hemispherical dome. The inside diameter of the cylinder is 158 feet. The vertical wall varies in thickness from 36 inches to 15 inches; the dome is 15 inches thick. The inside of the dome is 5 [feet] 6 [inches] above the top of the containment dome. 677 Dr. Saouma testified that the CEB should have been selected as the reference location because it is the last barrier in case of seismic load, and therefore it constitutes the Achilles heel of the whole structure. 678 He also testified that a seismic load is more likely to affect the CEB than a tunnel. 679 Dr. Saouma further stated that an important difference between the test specimens and the CEB is that the test specimens were about scale ( -inch depth whereas the wall of a CEB is about 36 inches). 680 Although he recognized that this is not unusual in component testing, Dr. Saouma stated that given the brittle nature of shear failure and associated size effect, the shear strength in the CEB will be lower than the one from the LSTP. 681 According to a paper cited by Dr. Saouma, the size effect refers to [t]he reduction in shear stress at shear failure as member depth of beams and slabs not containing stirrups increases[.] 682 Dr. Saouma testified that due to [the] size effect, the strength of a 36[-inch] deep beam ([modeling] the CEB 676 Id. § 3.8.1.1.

677 Id. § 3.8.4.

678 Tr. at 1046 (Saouma).

679 Tr. at 1047 (Saouma).

680 Ex. INT028, Dr. Saouma Rebuttal Testimony at 17 (non-public); Ex. INT032, Dr. Saouma Rebuttal Testimony at 17.

681 Ex. INT032, Dr. Saouma Rebuttal Testimony at 17.

682 Ex. INT042, Bentz, E. C. (2005)[,] Empirical modeling of reinforced concrete shear strength size effect for members without stirrups. ACI structural journal, 102(2), 232. at 232 [hereinafter Ex. INT042, Bentz] (non-public). Stirrups provide through-thickness or triaxial reinforcement.

See id.

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Official Use Only Proprietary Information wall) is about 26% lower than . . . a [-inch] one. 683 Because the LSTP used -inch beams, Dr. Saouma stated, the LSTP may significantly overestimate the strength of a 36-inch deep beam. Thus, the LSTP -inch beams would not be sufficiently representative of the below ground section of the CEB wall, which is 36 inches deep.

Dr. Saouma also testified that the reinforcement ratio of the test specimens is not representative of the CEB. 684 He stated that the reinforcement ratio may be representative of the [B Electrical Tunnel]. Even so[,] the longitudinal reinforcement [is] higher; [%] instead of 0.6[%], but that reinforcement threshold is not at all close to what we have in the CEB where the reinforcement threshold is 0.34[%] in both direction[s]. 685 Dr. Saoumas opinions are sufficient to meet C-10s burden to establish a prima facie case and the burden of proof on this scaling issue therefore shifts to NextEra.

c. NextEra and Staff Responses NextEra used the B Electrical Tunnel as a reference location, claiming it is representative of other structures and was the location where NextEra first identified ASR. 686 MPR, NextEras expert witnesses clarified, however, that the B Electrical Tunnel is not representative of the walls of Containment and the lower portions of the CEB, which are triaxially reinforced[]. 687 Regarding the test-model scaling issue raised by Dr. Saouma, NextEra witnesses testified that one of the primary reasons for performing the LSTP was because published test results for selected limit states were from specimens that were too small to be considered 683 Ex. INT028, Dr. Saouma Rebuttal Testimony at 18 (non-public); Ex. INT032, Dr. Saouma Rebuttal Testimony at 18.

684 Tr. at 770 (Saouma).

685 Tr. at 1046-47 (Saouma).

686 Ex. NER001, MPR Testimony at 76-77.

687 Id. at 77.

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Official Use Only Proprietary Information representative. 688 NextEra witnesses further testified that [n]o scaling of the test specimen dimensions were required because the beam dimensions (thickness, reinforcing bar size, reinforcing bar spacing, concrete cover over reinforcing bars) were similar or identical to the reference location at the plant-i.e., the B Electrical Tunnel at Seabrook. 689 NextEra witnesses asserted that [b]ecause the scaling factor between the fabricated LSTP specimens and the B Electrical Tunnel is 1.0 (i.e., no scaling required), proportionate scaling for location of reinforcement and diameter of reinforcement was not necessary. The LSTP specimens used the actual reinforcement bar sizes and the actual reinforcement spacing .

. . . 690 Staff witnesses testified that C-10s argument regarding scaling is immaterial because the LSTP specimens were almost full-scale compared to the bounding reference location, the B Electrical Tunnel:

The length and width of the test specimens are the actual dimensions at the reference location and the height is that of a representative segment (or slice) of that location . . . . The test 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. 691 Staff witnesses also stated that [b]ecause the LSTP supplements (rather than replaces) the design code, results from appropriately representative test specimens may be applied to reinforced concrete structures throughout Seabrook. 692 It is undisputed that the LSTP concrete specimens were representative of the dimensions of the B Electrical Tunnel, the reference location. The more difficult question, 688 Id. at 138.

689 Id.

690 Id. at 139.

691 Ex. NRC001-R, Staff Testimony at 52.

692 Id. at 53.

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Official Use Only Proprietary Information however, is whether the tunnel is sufficiently representative or bounding of other Seabrook structures such that the data obtained from the LSTP specimens may appropriately be applied to those other structures.

Witnesses for both the Staff and NextEra agreed that it would be reasonable to use the B Electrical Tunnel to model ASR because that was the worst ASR area. 693 The evidentiary record confirms that the tunnel has the highest through-thickness expansion measurements. 694 In addition, NextEra witnesses testified that the CEB is actually more reinforced than the B Electrical Tunnel on which the test specimens are based 695 and that therefore the test specimens are bounding of the CEB. Specifically, the CEB is reinforced in both the in-plane direction and the through-thickness direction in the lower portions. 696 NextEra witness Mr.

Sherman explained that the lowermost portion of the CEB building where it's below [ground],

where it's exposed to moisture, where we are seeing the [ASR] has through-[thickness]

reinforcement. 697 This is in addition to the in-plane reinforcement of the test specimens. 698 NextEra witness Dr. Bolourchi testified that the below ground area of the CEB has ASR. 699 He also testified that all the below [ground] area[s] which . . . show any sign[s] of ASR

. . . have through-thickness [reinforcement]. Above[-ground] is 15-inch concrete and there [is]

no sign of ASR in there. 700 In addition, Dr. Bolourchi testified that the through-thickness 693 Tr. at 1047 (Buford).

694 Ex. NER007, Seabrook [SMP] Manual Rev. 7, B-14 tbl.2 (providing pre-instrument through-thickness expansion measurements for locations in the B Electrical Tunnel) (non-public).

695 Ex. NER001, MPR Testimony at 76-77, 99.

696 Tr. at 700-02 (Sherman, Bolourchi).

697 Tr. at 701 (Sherman).

698 Tr. at 701 (Sherman); Ex. NER001, MPR Testimony at 99.

699 Tr. at 954 (Bolourchi).

700 Tr. at 1067 (Bolourchi).

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Official Use Only Proprietary Information reinforcement in the CEB is one of the highest reinforcement[s] you can get in the through-thickness. Therefore, we are not relying on the concrete alone. We are relying on concrete plus steel. And the steel is not impacted by ASR. 701

d. Findings of Fact and Board Analysis We are not persuaded that there is no ASR-induced cracking in above ground areas of Seabrook structures, although this does not defeat a finding of reasonable assurance. One above ground area of the CEB, the wall inside and above the equipment hatch, has sufficient ASR cracking to require monitoring during outages. 702 Also, Staff witnesses acknowledged that extensometers had been installed in both the above and below ground locations at Seabrook. 703 Extensometers are usually installed in Tier 3 areas, those with a CCI measurement above 1.0 mm/m (0.1%). 704 Thus, ASR has not only been identified in above ground Seabrook structures but at sufficiently high levels to require the installation of extensometers. The areas of the CEB above an elevation of 22 feet do not have the triaxial reinforcement that is present in either the elevations below 22 feet or the below ground areas, and so they may be as susceptible to ASR-induced cracking as other above ground areas of Seabrook structures. 705 Most of the above ground areas of the CEB do not have the triaxial reinforcement that is present in the below ground areas. 706 These areas may be as susceptible to the same ASR-701 Tr. at 1064-65 (Bolourchi).

702 Ex. NER007, Seabrook [SMP] Manual Rev. 7 at B-4 to -5 tbl.1 (non-public).

703 See Ex. NRC001-R, Staff Testimony at 64.

704 Ex. INT010, Original LAR at PDF 33 tbl.5.

705 Areas around CEB penetrations have additional reinforcement, with some penetrations such as the equipment hatch having triaxial reinforcement. Ex. 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) at 26-29 [hereinafter Ex. INT015, SGH Evaluation and Design Confirmation of As-Deformed CEB].

706 Id.; Tr. at 701 (Sherman), 1067 (Bolourchi).

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Official Use Only Proprietary Information induced cracking as other above ground areas of Seabrook structures. Because of the lower relative humidity at the surface, Seabrook structures, including the CEB, may show little or no surface cracking but may have significant interior cracking, where the relative humidity is at or above the 80% threshold necessary for ASR reactivity. 707 It is true, however, that the areas with the heaviest ASR cracking are generally below ground, 708 which provides some support for the selection of the B Electrical Tunnel as the reference location. But we must also consider the size effect described by Dr. Saouma. 709 As was explained above, the size effect causes lower shear strength for larger structures. 710 The critical issue, therefore, is whether the effect of the triaxial reinforcement in increasing shear strength is sufficient to offset the size effect.

Dr. Saouma cited Evan C. Bentz, Empirical Modeling of Reinforced Concrete Shear Strength Size Effect for Members without Stirrups, which concluded that [t]he size effect is real and shows decreasing shear stress at shear failure for larger beams that do not contain stirrups

. . . [t]he percentage of reinforcement is important in equations that determine the shear strength of beams without stirrups[.] 711 Thus, the Bentz article concludes that the size effect does not apply to beams with stirrups and that the amount of in-plane reinforcement is important.

The Seabrook CEB wall thickness varies from 36 inches at the base (El. -30 feet) to 27 inches from El. 11 feet to El. 40 feet and 15 inches above El. 40 feet. 712 The CEB is 228 feet 707 Ex. INT028, Dr. Saouma Rebuttal Testimony at 21-25 (non-public); Ex. INT032, Dr. Saouma Rebuttal Testimony at 21-25.

708 See Ex. NER007, Seabrook [SMP] Manual Rev. 7 at B-12 to -16 tbl.2 (non-public).

709 Ex. INT028, Dr. Saouma Rebuttal Testimony at 17-18 (non-public); Ex. INT032, Dr. Saouma Rebuttal Testimony at 17-18.

710 See supra notes 680-683 and accompanying text.

711 Ex. INT042, Bentz at 240 (non-public).

712 Ex. INT015, SGH Evaluation and Design Confirmation of As-Deformed CEB at 26-29.

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Official Use Only Proprietary Information tall. 713 Therefore, most of the CEB is approximately 2 feet thick or less, which is the depth of the test specimens in the LSTP, 714 thus precluding any size effect concerns for a large part of the CEB.

The entire portion of the CEB that is 36 inches in depth includes transverse reinforcement (stirrups) in both the hoop (circumferential) and meridional (longitudinal or vertical) directions, 715 which is a structural geometry that was not addressed in the Bentz article. 716 Also, the in-plane reinforcement of the CEB in the hoop and meridional directions of the 36-inch thick portion of the CEB is greater than the reinforcement of the shear test specimens of the LSTP. 717 At the hearing, NextEra witness Dr. Bayrak testified that size effect is a factor well known in the shear community. 718 However, he also testified that this is accounted for in ACI 318-71 because that version of the code mandates the use of a minimum quantity of transverse, through-thickness reinforcement in cases where the shear stress exceeds one-half of the concrete contribution to shear strength expression. The use of transverse reinforcement mitigates whats known as [the] size effect. 719 Dr. Saouma agreed with this, although he stated that [the increase of shear strength from the reinforcement] is coming at a price of additional stresses which were not accounted for in the design process. 720 713 Id. at 26.

714 Id. at 26-29; see Ex. INT019, MPR-4273 at 3-2 tbl.3-1; Ex. INT021, MPR-4273 at 3-2 tbl.3-1 (non-public).

715 Ex. INT015, SGH Evaluation and Design Confirmation of As-Deformed CEB at 26-28.

716 See Ex. INT042, Bentz at 240 (non-public).

717 Ex. INT015, SGH Evaluation and Design Confirmation of As-Deformed CEB at 26-28; Ex.

INT019, MPR-4273 at 3-2 tbl.3-1; Ex. INT021, MPR-4273 at 3-2 tbl.3-1 (non-public).

718 Tr. at 624 (Bayrak).

719 Tr. at 625-26 (Bayrak).

720 Tr. at 629 (Saouma).

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Official Use Only Proprietary Information Given the transverse reinforcement, which mitigates the size effect, the higher in-plane reinforcement of the 36-inch thick portion of the CEB, the small size of the 36-inch segment, and the fact that the wall thickness of a large majority of the CEB is 15 inches (which is much less than the wall thickness of the LSTP test specimens), the Board finds, based on a preponderance of the evidence, that the size effect will not reduce the shear response of the CEB structure relative to the LSTP test specimens.

With respect to Dr. Saoumas concern regarding the reinforcement of some test specimens, 721 NextEra witnesses testified that while [t]he LSTP specimens used the actual reinforcement bar sizes and the actual reinforcement spacing[,] there was one exception for the spacing of the longitudinal reinforcement in the shear specimens, which used additional rebar in the longitudinal direction to ensure a shear failure[.] 722 NextEra witnesses further testified that the use of additional longitudinal reinforcing bars in the shear test specimens provided additional flexural capacity, and therefore ensured that failure during load testing would be in shear rather than flexure. 723 MPR-3757 addresses the use of the longitudinal and perpendicular reinforcement spacing for the shear test specimens. 724 Similarly, Staff witnesses testified that the LSTP was not a model test; rather:

[I]t was a full-scale load test, consistent with the test methodology on which the ACI 318-71 empirical code equations for structural capacity (for strength limit states such as flexure and shear) were developed, created to determine the impact of ASR on structural capacity for specific limit states. The individual tests were designed to ensure that the failure mode of each test specimen supports the limit state of interest in that test. The purpose of the tests was . . . to validate the applicability and/or limitations of the ACI 318-71 code equations for estimating structural capacity for critical limit states for ASR-affected reinforced concrete structures at Seabrook. 725 721 Tr. at 1046-47 (Saouma).

722 Ex. NER001, MPR Testimony at 139.

723 Id. at 139-40.

724 See Ex. NER026, MPR-3757 § 3.2.3 (non-public).

725 Ex. NRC001-R, Staff Testimony at 53-54.

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Official Use Only Proprietary Information We find the scaling, reinforcement, and size of the specimens in the LSTP reasonable and sufficient to provide reasonable assurance of adequate protection of public health and safety.

4. Boundary Conditions

a. Motion in Limine NextEra argued that Dr. Saoumas testimony regarding dimensions and boundary conditions introduces new challenges to the execution of the LSTP and deficiencies in the LAR that were not advanced in the original Petition. 726 Specifically, NextEra seeks to exclude section C.2.2.2 from Dr. Saoumas pre-filed testimony, as well as sections D.4.1 and D.4.2 from Dr.

Saoumas rebuttal testimony, claiming that he raised new arguments that could have been raised at the outset and are unrelated to the reformulated contention. 727 For the same reasons addressed earlier, supra Part VIII.A.3.a, the Board denies the Motion in Limine in this respect and holds section C.2.2.2 of Dr. Saoumas pre-filed testimony and sections D.4.1 and D.4.2 of Dr. Saoumas rebuttal testimony are within the scope of this proceeding. 728

b. C-10s Prima Facie Case Dr. Saouma suggested that NextEra made errors in the design of the LSTP regarding the specimen boundary conditions. 729 Specifically, he stated that [i]n a test, the model must be subjected to the same conditions (support, restraints and load) as the prototype (Seabrook). 730 He further stated that the [LSTP] tests modeled only the [out-of-plane] shear and not the in-726 NextEra MIL 2 at 17-18.

727 Id.

728 Ex. INT027, Dr. Saouma Pre-Filed Testimony § C.2.2.2 generally critiqued the boundary conditions used in the LSTP, whereas Ex. INT032, Dr. Saouma Rebuttal Testimony § D.4.1 stated that the lack of testing for in-plane shear is a concern, and § D.4.2 developed the argument that the lack of in-plane shear testing is a concern by stating the CEB will be affected by in-plane shear forces during a seismic excitation.

729 Ex. INT027, Dr. Saouma Pre-Filed Testimony § C.2.2.2.

730 Id. at 12.

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Official Use Only Proprietary Information plane [and that] . . . [o]ut-of-plane results may not be directly applicable to in-plane. 731 Dr.

Saouma also stated that axial forces from in-situ boundary conditions can negate the prestressing effect observed in ASR-affected reinforced concrete and that the prestressing

[effect] may be dwarfed by . . . axial loads [from gravity] and . . . cannot be relied upon. 732 Thus, he testified that as a result of these deficiencies the [LSTP] cannot be seen as a representative model of the prototype (Seabrook). 733 Dr. Saoumas testimony provides a plausible analysis to support his opinion. C-10 has therefore satisfied its burden to present a prima facie case.

c. NextEra and Staff Responses Regarding boundary conditions, NextEra witnesses testified that the test setups for the Shear and Reinforcement Anchorage Test Programs used a point loading arrangement. 734 NextEra witnesses acknowledged that [t]his loading is different than the conditions for some structures at Seabrook, which have uniform loading due to hydrostatic loading from the exterior of the structure, the weight of the structure, and the global application of potential loads (e.g.,

seismic). 735 Thus, [t]he test setups were not aimed at replicating boundary conditions (i.e.,

load or deformation compatibility) at Seabrook. Rather, the test setups were adopted since they are industry standard tests for studying shear behavior and reinforcement anchorage. 736 731 Id.

732 Id. at 13.

733 Id.

734 Ex. NER001, MPR Testimony at 74 (citing Ex. NER015, MPR-3848, Rev. 0 Seabrook Station, Approach for Shear and Reinforcement Anchorage Testing of Concrete Affected by Alkali-Silica Reaction (Apr. 2013) (FP100818) § 4.3 [hereinafter Ex. NER015, MPR-3848] (non-public)).

735 Id.

736 Id.

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Official Use Only Proprietary Information NextEra witnesses stated that [r]eplication of the in-situ conditions would have been excessively complex and is ultimately unnecessary for reasonable assurance. Considering the variety of loading and boundary conditions present at Seabrook, it is not practical or even possible to replicate every location. 737 As NextEra witness Dr. Bayrak put it, having to focus on replicating all aspects of everything at every location would result in building another nuclear power plant. 738 Dr. Bayrak further emphasized that ACI 318-71 expressions do not aim to replicate the boundary conditions for the myriad structures in which the design expressions [(i.e., design equations)] are used. Instead, ACI 318-71 presents design expressions that can uniformly be applied to concrete structures. 739 Following the approach of ACI 318-71, the LSTP used the most severe loading and boundary conditions for the limit states of interest and were consistent with the approaches used to develop the ACI Code equations of interest, which provide the design basis for the plant. 740 NextEra witnesses testified:

The test configuration (simply supported beam with point loading) is typical for testing used to develop empirical ACI code expressions. The experimental design is for separate effects testing and deliberately omitted additional forces (e.g., axial forces) that might impact the results, which is consistent with industry practices for shear testing. For Seabrook, additional forces due to building configuration or other loads (e.g., seismic) are accounted for in the SEM and did not need to be simulated in the load tests. 741 737 Id. at 74-75.

738 Tr. at 428-29 (Bayrak).

739 Ex. NER001, MPR Testimony at 75 (citing Ex. NER015, MPR-3848 § 4.3 (non-public)).

740 Id.

741 Id. at 98 (citing Ex. NER015, MPR-3848 § 4.3 (non-public); Ex. NRC051, Report of ACI-ASCE (American Society of Civil Engineers) Committee 326, Shear and Diagonal Tension (1962) (non-public)).

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Official Use Only Proprietary Information With respect to Dr. Saoumas concern regarding the tests not modeling in-plane shear, NextEra witnesses further testified:

Out-of-plane shear is perpendicular to the plane of a wall (e.g., a force pushing on the wall surface). In-plane shear occurs in the plane of a wall (e.g., a force pushing down from the top of the wall). In the context of Seabrook, out-of-plane shear is not resisted by reinforcement, whereas in-plane shear is. 742 According to NextEra, it demonstrated through review of published literature that one-way shear with reinforcement was not a concern for Seabrook . . . [h]ence, there was no need to evaluate in-plane shear as part of the LSTP. 743 Staff witnesses agreed that the LSTP did not test for the in-plane shear mode because the out-of-plane shear failure is bounding of in-plane shear. 744 Staff witnesses, like those of NextEra, judged the out-of-plane shear failure mode to be more critical than [the] in-plane shear mode. 745 Staff witnesses noted that under the ACI 318-71 code the nominal permissible out-of-plane shear stress in concrete is . . . 2*fc which contrasts with the greater allowable total shear stress of 10*fc for in-plane shear[,] . . . [w]here fc is the specified minimum concrete compressive strength[]. 746 For C-10s part, Dr. Saouma testified that [t]he fact that the ACI 318-71 code allows 10 times the square root of the compressive strength for [in-plane] shear, as opposed to only two times for [out-of-plane], is irrelevant. 747 He further testified that:

742 Id. at 140.

743 Id. (citing Ex. NER018, MPR-3727 at 6-8 tbl.6-4; Ex. NER019, Bayrak White Paper at 12 tbl.4 (non-public)); Ex. 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) § 7.2.2 [hereinafter Ex. NRC075, Deschenes, et al.].

744 NRC Staff SOP at 51 (citing Ex. NRC001-R, Staff Testimony at 53-55).

745 Ex. NRC001-R, Staff Testimony at 54-55.

746 Id. (citing Ex. NRC049, ACI 318-71 §§ 11.4.1, 11.16.5 (non-public)).

747 Ex. INT032, Dr. Saouma Rebuttal Testimony at 18.

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[T]he relative loss in strength will be equal to the square root of the fraction of the loss because the 2 and the 10 cancel out[]. For instance, if the original compressive strength is 100 (never mind the units), and due to ASR the compressive drops to 70, the loss in shear strength for both in-plane and [out-of-plane] will be equal to the square root of 70 divided by 100 (0.83). 748 Therefore, he stated that the concrete deterioration of the in-plane shear should be accounted for . . . [because] the analysis of the container is not accounting for this loss. 749 In other testimony, however, Dr. Saouma appeared to recognize the greater importance of out-of-plane shear:

Ultimately, the major concern about the reduced shear strengths is due to the lateral load. There is not really a major concern about the safety of the structure due to the gravity load, the vertical load. It assumes there will be a lateral load due to seismic activity. This is where the problem occurred. Because to resist a lateral load is the shear strength of the concrete. 750 NextEra witnesses testified that NextEra:

[D]id consider axial compression during planning of these tests. The ACI [318-71] shear design methodology recognizes that axial compression improves the shear strength of reinforced concrete, and conversely, axial tension weakens the shear strength of reinforced concrete. In this context, it is important to recognize two facts: (1) There is no reason to believe that the beneficial effects of axial compression to shear strength would be any different for ASR-affected concrete, particularly in view of the publicly available test data, and (2) restraint provided by the actual structural configurations present at Seabrook introduces axial restraint (i.e., compression) forces that would benefit shear strength, thus making the testing conservative (because the test setup did not have the benefit of being part of a larger structure that provides restraint). This effect is taken into account by the structural analysis methodology. Accordingly, it would not have been appropriate to also include axial compression forces in the experimental program. 751 Staff witnesses testified that they agreed that NextEra did not need to test for axial forces caused by deadweight, explaining that these axial forces are compressive and have a 748 Id. (emphasis omitted).

749 Id.

750 Tr. at 361 (Saouma).

751 Ex. NER001, MPR Testimony at 141-42.

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Official Use Only Proprietary Information beneficial effect on structural capacity in flexure and shear for in-situ structures such as those at Seabrook. 752

d. Findings of Fact and Board Analysis The Board agrees with NextEra that the variety of loading and boundary conditions present at Seabrook makes it impractical to replicate every location of concern. The Board also agrees with NextEra that the ACI 318-71 design equations do not aim to replicate the boundary conditions for each of the large number of structures to which they are applied. Instead, ACI 318-71 can be uniformly applied to concrete structures even though there may be variations within the specific configuration of structural components.

The Board concludes that NextEra has met its burden to show by a preponderance of the evidence that the LSTP was sufficiently representative of the boundary conditions of Seabrook structures. It was reasonable for the LSTP to focus on out-of-plane shear because out-of-plane shear failure is bounding of in-plane shear failure, and the test configuration provides a conservative evaluation of the structural capacity of Seabrook. We also conclude that NextEra did not need to test for axial forces due to deadweight because those forces have a beneficial effect on structural capacity in flexure and shear. Therefore, it was conservative to exclude those forces from the test program. 753

5. Effect of Reinforcement (Use of Original Material Properties)

It is undisputed that ASR degrades the material properties of concrete, including compressive strength, elastic modulus, and tensile strength. 754 Because concrete material 752 Ex. NRC001-R, Staff Testimony at 55.

753 Although not part of the LSTP, the specific configuration and boundary conditions of each Seabrook structure affected by ASR and its foundation are included in the SEM and are thus accounted for in the calculation of the structural demand for each structure. The methodology used to calculate structural demand is outside the scope of the proceeding. See infra Part VIII.F.1; see supra note 741 and accompanying text.

754 Ex. INT027, Dr. Saouma Pre-Filed Testimony, at 6; Ex. INT031, Dr. Saouma Review of Selected Documents at 12-14; Ex. NER001, MPR Testimony at 39 (ASR can produce cracking

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Official Use Only Proprietary Information properties are used as direct inputs to Code equations for determining structural capacity, a decrease in concrete material properties implies a corresponding decrease in calculated structural capacity. 755 Relying on the LSTP, however, NextEra concluded that in reinforced concrete, the presence of reinforcing bars and the consequent chemical prestressing effect causes the structural performance of ASR-affected reinforced concrete to depart from what would be calculated using the ASR-affected material properties as inputs to the code expressions. 756 NextEra decided it could use the original, non-degraded material properties as inputs to the code equations for determining structural capacity when ASR-induced expansion is within the limits of the LSTP. 757 C-10 challenged this determination. 758

a. Motion in Limine NextEra moved to exclude testimony on the use of original material properties claiming these arguments are new and beyond the scope of the reformulated contention. 759 We deny NextEras motion in this regard. In Contention B, one of the bases of the reformulated contention, C-10 challenged NextEras reliance on the beneficial effect of the confinement provided by reinforcement and the resulting chemical prestressing effect. Contention B, as admitted by the Board, alleges that [t]he LAR misconstrues expansion occurring within a reinforced concrete structure due to the [ASR] because any mitigation of lost structural capacity, in concrete, and eventually causes degradation of its material properties-compressive strength, elastic modulus, tensile strength, etc.-as measured from typical tests conducted on cylinders or cores.); Ex. NRC001-R, Staff Testimony at 7 ([ASR] cracking degrades the mechanical material properties of the affected concrete.).

755 Ex. NER001, MPR Testimony at 39-40 (citing Ex. NRC049, ACI 318-71 § 11.4 (non-public)).

756 Id. at 41.

757 Id. at 60.

758 See infra Part VIII.A.5.b.

759 NextEra MIL 2 at 21-24.

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Official Use Only Proprietary Information due to reinforcement, is temporary and unpredictable. 760 In support of Contention B, C-10 directly disputed the LARs claim that, although ASR reduces the material properties of concrete, this does not necessarily result in a corresponding decrease in capacity of a reinforced concrete structure [because] ASR-induced expansion in reinforced concrete has a prestressing effect that mitigates the loss of structural capacity that would be assumed based on the change in material properties. 761 If C-10 is correct, then NextEras structural evaluations, which assume undegraded material properties because of the beneficial effect of reinforcement as long as ASR remains within the expansion limits, 762 would be based on an incorrect assumption derived from the LSTP. According to NextEra witnesses, the LSTP confirmed that the original code capacities and standard methods of computing stiffness could be used in structural analyses and evaluations on the capacity side of the finite element analysis (FEA). 763 Because NextEra used a conclusion from the LSTP to determine which material properties to use in the FEA to assess capacity, C-10s testimony challenging the use of original material properties is within the scope of the proceeding. If the LSTP is found not to be sufficiently representative, that would call into question any conclusions stemming from the LSTP, such as the use of the original material 760 LBP-17-7, 86 NRC at 107.

761 Ex. INT010, Original LAR at PDF 10; C-10 Petition at 4-5; see also Ex. NER001, MPR Testimony at 38 (Prestressing of concrete refers to the approach of applying a compressive load to improve the tensile capacity of the concrete member. When the concrete member is in service, if tensile loads are applied, the compressive prestress (i.e., pre-compression) must be completely overcome before a portion of the member is exposed to net tension, at which point cracking may ensue. Because concrete is much stronger in compression than tension, prestressing can improve in-service performance for certain applications.).

762 See Ex. INT014, MPR-4288 at 2-3 (non-public); Ex. INT012, MPR-4288 at 2-3.

763 Ex. NER004, SGH Testimony at 17-18 (We evaluated the LSTP information regarding stiffness and capacity in much the same way that we evaluated other academic literature and testing programs. We considered these conclusions (i.e., that stiffness and capacity are not impacted by ASR within the limits of testing) in developing the baseline assumption in the SEM that existing code capacities and standard methods of computing stiffness can be used in structural analyses and evaluations.). The FEA is explained supra Part II.A.

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Official Use Only Proprietary Information properties to determine structural capacity. And if the use of original material properties caused NextEra to overestimate the capacity of Seabrook seismic Category I structures, its support for the LAR would be undermined. Therefore, NextEras Motion in Limine is denied regarding the use of original material properties.

b. C-10s Prima Facie Case Dr. Saouma stated that ASR will reduce the tensile strength and the elastic modulus of concrete . . . by as much as 60%. As to the compressive strength, it has long been assumed that it is not affected by ASR; however there is recent evidence to the contrary . . . . 764 He also stated that [t]he concrete material is degraded by ASR (by virtue of its correlation to the tensile strength)[.] 765 He further testified that the elastic modulus is reduced by the deteriorated nature of the existing concrete. 766 Dr. Saouma also testified that ASR undoubtedly affects the elastic modulus, which will result in larger displacements, and in turn [an] increased likelihood of cracking[.] 767 He also stated that ASR will reduce the tensile and shear strength of concrete while increasing [its] propensity [for] larger deformation[s]. This in turn increases the likelihood of cracking and reduces the ability of a structure to resist [a] lateral seismic load. 768 Although Dr. Saouma stated that [c]oncrete shear strength will decrease rather than increase because of ASR, he acknowledged that [r]einforced concrete . . . will not have a decrease in shear strength because of [the] prestressing effect[.] 769 Dr. Saouma stated that the 764 Ex. INT031, Dr. Saouma Review of Selected Documents at 13 (citations omitted).

765 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 26.

766 Id. at 25 ([T]he elastic modulus should have been reduced, and this in turn will reduce the stiffness of the [nuclear containment vessel structure]. Indeed [Ex. NRC049, ACI 318-71 § 19.2.2.1 (non-public)] has an approximate equation for the elastic modulus in terms of the compressive strength. However, this cannot be valid for a deteriorated concrete as it is outside the assumptions of the ACI equation.); Tr. at 950 (Saouma).

767 Ex. INT031, Dr. Saouma Review of Selected Documents at 15; see Tr. at 314-15 (Saouma).

768 Ex. INT031, Dr. Saouma Review of Selected Documents at 14.

769 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 17.

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Official Use Only Proprietary Information reduction in concrete shear strength due to ASR is a universal material characteristic that can be used inside a finite element programs constitutive relation (a) to relate stress to strain; and (b) to define a yield surface or failure load. 770 Dr. Saouma recognized the need to take into account the effect of confinement on the degraded material properties. 771 Still, he testified that this should be done as part of the FEA, 772 and he cited examples where researchers were able to capture increasing strengths as a result of chemical [prestressing] of ASR. 773 Dr. Saoumas rebuttal testimony, which responded to NextEras claim that the chemical prestressing effect is fundamentally beneficial, explained that [w]hile MPR state[d] that the beneficial effects of confinement are recognized in the structural engineering community, its potentially adverse effects are also recognized[.] 774 He explained that [t]he real possibility of excessive steel stresses resulting in premature fracture or yielding was also reported . . . .

Indeed, in this paper, it is shown that chemical prestressing has caused the rupture of steel and thus partial collapse of a bridge. 775 In further support of his opinion, Dr. Saouma cited an FSEL study prepared for the Texas Department of Transportation that identified more than thirty cases of fractured 770 Id. In an FEA, constitutive relation(s) are used for the prediction of specific physical phenomena in a finite element method or other numerical analysis, such as the response of a material to an applied force.

771 Tr. at 651 (Saouma) ([A]ny semi-reasonable finite element code would be able to capture the interaction between the material and the surrounding [reinforcement] and the chemical

[prestressing].).

772 Id.

773 Id.

774 Ex. INT032, Dr. Saouma Rebuttal Testimony at 19.

775 Id. (citing Ex. INT043, Miyagawa et al., Fracture of Reinforcing Steels in Concrete Structures Damaged by Alkali-Silica Reaction. Journal of Advanced Concrete Technology, 4(3), 339-355 (2006)). Yielding of the reinforcing bars refers to permanent deformation of the steel, which occurs when deflection of the beam produces stresses in the reinforcing bars that reach their yield strength. This failure mode is preferred for structural design because it is more gradual than the sudden brittle failure of concrete that could occur with failure of reinforcement anchorage at the lap splice. Ex. NER001, MPR Testimony at 102-03.

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Official Use Only Proprietary Information reinforcements . . . in bridges and other structures affected by ASR. 776 The FSEL study noted that this discovery by Japanese researchers led them to reassess the impact of ASR on structural safety and serviceability stating that [a]s long as reinforcing steels are not broken due to ASR-caused expansion, the safety of a structure is considered not to be seriously compromised. However, the safety of a structure becomes questionable when the confinement of the concrete becomes degraded due to fracture of reinforcing steel bars (Miyagawa 2006). 777 Further, the FSEL study stated that [p]erception of ASR as structurally harmless deterioration persisted until the recent discovery of fractured reinforcement in the deteriorated structures of Japan. It was immediately recognized that the ASR-induced fracture of reinforcement would lead to a sudden loss of structural capacity. 778 Dr. Saouma acknowledged that prestressing reduces the impact of degraded material properties on structural capacity. 779 However, he also testified that the prestressing effect is accompanied by increases in tensile and compressive stresses that were not accounted for in the design process. 780 He further stated that strain gauges 781 should have been placed on the LSTPs shear beam to assess and quantify the adverse effects of the chemical prestressing[.] 782 776 Ex. INT032, Dr. Saouma Rebuttal Testimony at 19 (citing Ex. NRC075, Deschenes, et al. at 25-26).

777 Ex. NRC075, Deschenes, et al. at 26.

778 Id. at 28.

779 Tr. at 627-29, 829 (Saouma).

780 Id.; Ex. INT032, Dr. Saouma Rebuttal Testimony at 20.

781 Ex. NER004, SGH Testimony at 37 ([O]ngoing expansion is monitored using demountable mechanical strain gauges that more precisely measure the distance between gauge pins permanently installed in the concrete.).

782 Ex. INT032, Dr. Saouma Rebuttal Testimony at 21.

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Official Use Only Proprietary Information We conclude that C-10 satisfied its burden to make a prima facie case on the issues raised by Contention B and incorporated in the reformulated contention.

c. NextEra and Staff Responses NextEra witnesses acknowledged that ASR in reinforced concrete still causes a reduction in material properties like unreinforced concrete. 783 In reinforced concrete, however, NextEra witnesses stated that the presence of reinforcing bars and the consequent chemical prestressing effect causes the structural performance of ASR-affected reinforced concrete to depart from what would be calculated using the ASR-affected material properties as inputs to the code expressions. 784 According to NextEra witnesses, the LSTP showed that because of the interaction between concrete and reinforcing in a reinforced concrete member, the strength and stiffness of the overall members are not reduced within certain ASR strain limits. 785 NextEra concluded that the original elastic modulus can be used because the

[u]nreduced design material stiffness properties can adequately represent ASR-impacted reinforced concrete sections of the CEB structure. 786 NextEra witnesses also emphasized that:

[W]hile ASR may degrade both the strength and stiffness of the unconfined concrete material, the research has demonstrated that, within certain ASR strain limits, neither the strength nor the stiffness of structural elements is degraded below that predicted by code equations and principles of structural mechanics if original concrete properties are used. 787 783 Ex. NER001, MPR Testimony at 41.

784 Id.

785 Ex. NER004, SGH Testimony at 61-62.

786 Ex. INT015, SGH Evaluation and Design Confirmation of As-Deformed CEB at 22.

787 Ex. NER004, SGH Testimony at 59 (citing Ex. INT019, MPR-4273; Ex. NER001, MPR Testimony at 58-60) (emphasis omitted).

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Official Use Only Proprietary Information For example, Table 4 of the ISE document provides the [l]ower bound residual mechanical properties as percentage of values for unaffected concrete at 28 days. 788 The ISE document notes that:

It is emphasized that the residual strength and stiffnesses in actual structures will be modified from the figures in Table 4 [which show reductions in properties due to ASR]. This is because the concrete in actual structures is generally restrained by adjacent material and is in a biaxial or triaxial stress state. These effects will tend to reduce the damage to the concrete and increase its residual mechanical properties. 789 On this basis, NextEra witnesses testified that the original concrete material properties can appropriately be used in the structural evaluations within the limits defined by the LSTP. 790 Staff witnesses largely supported NextEras testimony and stated that:

Because of the in-situ confinement and the interaction between the reinforcing steel and the concrete, the load-carrying behavior of ASR-affected structures is generally expected to be better than would be expected from the material properties measured on test specimens or cores. Therefore, it is important that reinforced concrete structures affected by ASR be evaluated based on the impact on structural strength of a reinforced concrete composite system, and not necessarily on individual concrete material properties obtained by extracted core samples. 791 Thus, according to Staff witnesses, the results of the LSTP demonstrate that there is no impact on [the] in-situ structural capacity of reinforced concrete components within the expansion levels identified in the [LSTP]. 792 In sum, both NextEra and the Staff agreed that it is not necessary to input the degraded material properties in the FEA as long as ASR-induced expansion is within the expansion limits of the LSTP.

788 Ex. NER012, ISE Structural Effects of [ASR] at 14 tbl.4 (non-public).

789 Id. at 14 (non-public).

790 Ex. NER001, MPR Testimony at 54.

791 Ex. NRC001-R, Staff Testimony at 9.

792 Id. at 70; Ex. INT024, Final SE at PDF 40.

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Official Use Only Proprietary Information With respect to the NRCs regulations, Staff witnesses testified that the relevant issue is the effect that a degradation mechanism may have on structural properties rather than material properties. 793 Therefore, Staff witnesses stated that the relevant question is whether a reinforced concrete structure at Seabrook, as a whole, is capable of fulfilling its intended safety functions despite the presence of ASR. 794 In other words, [t]o determine whether an ASR-affected reinforced concrete structure or structural component remains capable of fulfilling its intended functions, it is the structural strength (as a reinforced concrete composite system) that matters and not individual material strengths. 795 In disputing Dr. Saoumas claims in his testimony that NextEra confused material strength with structural strength, 796 Staff witnesses testified that:

Dr. Saouma is referring to the material properties of concrete (e.g., compressive strength, tensile strength, etc.). When affected by ASR, the material properties of concrete are degraded. This is well known in existing ASR literature and the results of the LSTP showed the expected reductions in material properties.

NextEra acknowledged these results; however, the entire point of the LSTP was to demonstrate that although concrete material properties may be reduced, the structural performance of the reinforced concrete member can still be conservatively estimated by the design basis code equations. 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 identified limits from the LSTP, regardless of the reductions in material strength. 797 In response to Dr. Saoumas testimony that the chemical prestressing effect is accompanied by increases in tensile and compressive stresses that were not accounted for in the design process, NextEra witness Dr. Bayrak testified that [i]n the context of axial compressive strength of an element, it is, in fact, true that . . . the chemical [prestressing effect] .

793 Ex. NRC001-R, Staff Testimony at 8-9.

794 Id.

795 Id.

796 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 17.

797 Ex. NRC001-R, Staff Testimony at 58.

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. . offers a lot of different benefits here and there is a negative impact, but Dr. Bayrak also stated that the negative impact has been accounted for in the SGH analyses. 798 With regard to Dr. Saoumas concern that strain gauges should have been placed on the LSTPs shear beam specimen, Dr. Bayrak testified that strain gauges typically fail when used in tests such as those conducted in the LSTP that accelerate the rate of ASR progression. 799

d. Findings of Fact and Board Analysis The parties agreed on four issues. First, that ASR degrades the material properties of concrete, including compressive strength, elastic modulus, and tensile strength. Second, despite the acknowledged degrading effect of ASR, reinforced concrete will not have a decrease in shear strength because of the chemical prestressing effect. Third, any calculation of structural capacity must consider the effect of prestressing on the capacity of Seabrook structures. Finally, chemical prestressing produces both beneficial and negative impacts.

The parties disagreed, however, on how the prestressing effect should be evaluated.

NextEra chose to use the original material properties, not the degraded properties, as inputs to the code equations used to calculate structural capacity. It asserted it did so because the resulting calculations of structural capacity were consistent with the results of the LSTP, which showed no loss of structural capacity within the identified expansion limits. 800 On the other hand, Dr. Saouma prefers that the degraded material properties be incorporated into the FEA as structural capacity and that it captures the beneficial effect of prestressing. 801 NextEra also 798 Tr. at 630 (Bayrak).

799 Tr. at 631 (Bayrak).

800 Ex. NER004, SGH Testimony at 61-62; Ex. INT015, SGH Evaluation and Design Confirmation of As-Deformed CEB at 22; Ex. NRC001-R, Staff Testimony at 70.

801 Tr. at 650-55 (Saouma).

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Official Use Only Proprietary Information chose to capture the interaction between the rebar and the expanding concrete through the testing of actual concrete specimens. 802 The Board finds that neither approach has any obvious superiority to the other. Dr.

Saoumas approach would utilize degraded material properties taken directly from the testing of Seabrook cores, which would avoid the need to rely on the LSTP results that raise the various questions about representativeness. 803 NextEra witness Dr. Bolourchi testified, however, that Dr. Saoumas modeling approach would require the evaluation of numerous additional parameters and instrumentation of the Seabrook structures, not just testing of core borings. 804 NextEras approach has the advantage of relying on actual testing to determine the effect of the rebar on the expanding concrete. In the absence of a reason to prefer Dr. Saoumas recommended approach, the Board concludes that it was reasonable and consistent with NRC regulations for NextEra to use the nondegraded, original concrete material properties and code equations in the structural capacity calculations.

The other area of disagreement is the potential for ASR to cause or contribute to the fracture or yielding of reinforcing steel bars and a resulting loss of structural capacity. While Dr.

Saouma has not established that this will occur at Seabrook, he has raised a substantial question as to the likelihood that it may eventually happen. 805 The FSEL study cited by Dr.

Saouma refers to bridges and other structures in Japan affected by ASR where reinforcement damage has occurred. 806 The reports authors stated that it is difficult to comment on the potential for reinforcement fractures in ASR-affected structures found within the United 802 Tr. at 650 (Simons).

803 Tr. at 650-52 (Saouma).

804 Tr. at 652-53 (Bolourchi).

805 Ex. INT032, Dr. Saouma Rebuttal Testimony at 19-21.

806 See Ex. NRC075, Deschenes, et al. at 25-29.

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Official Use Only Proprietary Information States. 807 They noted that [t]he results of Miyagawas study on fracture mechanisms [in Japan] suggest that reinforcement is only subject to brittle failure when significant damage exists at the interior of the bend, but that American practice dictates the use of large radius bends: two times the bar diameter for the reinforcement used within the Japanese study. 808 But the FSEL study did not rule out the possibility of rebar fractures in the United States, observing that the lower ductility standards used in the manufacture of American reinforcement may offset the benefits of larger bend radii. 809 The SGH analyses referred to by Dr. Bayrak show that at present the stress on the rebar is well below the yield strength. 810 This unrebutted evidence is sufficient to justify a reasonable assurance finding regarding the immediate risk of rebar fracture or yielding. At the same time, however, these SGH analyses in no way preclude the significant risk posed by localized rebar fracture or yielding that might reasonably result from continued ASR expansion over the next thirty years of licensed operation. Dr. Bayrak testified that we can all safely assume, as it was assumed in NextEra programs, that the expansion potential is rather high. Much higher than the limits that are in place. 811 Dr. Saouma has identified a plausible risk that rebar fracture or yielding may occur in the highly stressed areas of seismic Category I structures from the negative impacts of the chemical prestressing effect. As ASR expansion increases, it is reasonable to expect that the negative impacts of chemical prestressing will also increase.

807 Id. at 28.

808 Id. at 29.

809 Id. For this reason, we are not persuaded that the Seabrook reinforcement steel is not subject to a risk of rebar brittle fracture because it was designed in accordance with codes that do not permit rebar bending to the extent that would be required for susceptibility to rebar fracture. Ex. INT010, Original LAR at PDF 21 tbl.3. Moreover, this statement in the LAR does not address the risk of rebar yielding.

810 Ex. INT022, SEM at PDF 91-92 tbl.1.

811 Tr. at 782 (Bayrak).

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Official Use Only Proprietary Information We have reviewed NextEras Structures Monitoring Program, but we have not been able to locate a provision for monitoring the future risk of reinforcement fracture or yielding. 812 NextEra witness Mr. Carley testified that when NextEra removes a concrete core to install an extensometer and exposes the rebar, we verify that the rebar is solid, pristine, not rusting. No deterioration of the rebar. 813 While this confirms that it is possible to examine installed rebar for signs of deterioration, the examination described by NextEra witness Mr. Carley apparently only occurs in those areas where NextEra happens to uncover the rebar while installing an extensometer. Insofar as future analyses suggest the stress from ASR expansion is approaching the yield strength of the rebar in one or more areas, there is no evidence in the record that NextEras existing monitoring efforts will ensure that rebar fracture or yielding either does not occur or is detected if it has occurred. The Board therefore concludes that, in order to provide reasonable assurance of adequate protection of public health and safety, it is necessary to add a license condition requiring the development of such a monitoring program contingent on the results of future stress analyses, 814 as follows:

If stress analyses conducted pursuant to the SEM show that the stress in the rebar from ASR-induced expansion and other loads will exceed the yield strength of the rebar, NextEra must develop a monitoring program sufficient to ensure that rebar failure or yielding does not occur, or is detected if it has already occurred, in the areas at-risk of rebar failure or yielding.

With the addition of this license condition, the Board resolves in NextEras favor the issues raised by Contention B and incorporated in the reformulated contention.

812 See generally Ex. NER007, Seabrook [SMP] Manual Rev. 7 (non-public).

813 Tr. at 532 (Carley).

814 See Ex. NER007, Seabrook [SMP] Manual Rev. 7 at 4-1.0 to -2.1 (non-public).

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6. Summary of Board Conclusions on Representativeness Issues The Board holds as to Part VIII.A.3 (Test Specimen Scaling, Reinforcement, and Size) and Part VIII.A.4 (Boundary Conditions) that the LSTP provided data that is sufficiently representative of Seabrook structures to provide reasonable assurance of adequate protection of public health and safety. As to Part VIII.A.2 (Concrete) and Part VIII.A.5 (Effect of Reinforcement (Use of Original Material Properties)), the Board has identified significant uncertainties that preclude a reasonable assurance finding absent the conditions imposed by the Board. 815 With those conditions added, however, the LSTP data is sufficiently representative to satisfy regulatory requirements as to all the representativeness issues raised by C-10.

B. ASR Monitoring Intervals Under the SMP, NextEra will conduct periodic inspections of ASR-affected structures depending on the severity of ASR expansion as determined via in-situ monitoring. 816 Thus, Seabrook structures with no symptoms of ASR are inspected every five or ten years based on existing SMP requirements. 817 Locations with ASR symptoms and with CCI values below 1.0 mm/m (0.1%) in-plane expansion are monitored every two and a half years. 818 And locations with CCI values of 1.0 mm/m (0.1%) or greater are monitored every six months for in-plane expansion, through-thickness expansion, and volumetric expansion. 819 815 CLI-19-7, 90 NRC at 11 (citing Vt. Yankee, CLI-06-8, 63 NRC at 238).

816 Ex. NER007, Seabrook [SMP] Manual Rev. 7 at 2-1.7, 2-1.9 to -1.15, 3-1.10 (non-public).

817 Id. at 2-1.7 to -1.8 (non-public).

818 Ex. INT010, Original LAR at PDF 33 tbl.5.

819 Id.; Ex. NER001, MPR Testimony at 125.

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1. C-10s Prima Facie Case In Contention H, C-10 presented, and we admitted, a challenge to the appropriate length of [ASR] monitoring intervals. 820 In his testimony, Dr. Saouma stated that NextEra erroneously assumed that ASR expansion is linear because ASR expands according to a sigmoid curve, which is a plot of expansion versus time that starts linearly and then curves more rapidly upwards before plateauing. 821 The chemical progression of ASR is generally understood to follow a sigmoid curve, which consists of a dormant period, an active period, and . . . a period where [ASR is] petered out. 822 Dr. Saouma focused on NextEras failure to establish Seabrooks location on the sigmoid curve. 823 The sigmoid curve for ASR at Seabrook, Dr.

Saouma testified, is essential to establishing proper monitoring intervals. 824 Based on Dr.

Saoumas testimony, C-10 challenged NextEras characterization of ASR progression at Seabrook as a slow reaction, and argued that Seabrook falls within the slower phase of ASR now, but that the rate of expansion will accelerate at some point. 825 Also, Dr. Saouma asserted that NextEras method of deriving concrete expansion from the degradation of its elastic modulus is not universally accepted. 826 Because Dr. Saoumas testimony provides a plausible analysis to support his expert opinion, C-10 has satisfied its burden to present a prima facie case.

820 LBP-17-7, 86 NRC at 125; see id. at 121-25.

821 Ex. INT032, Dr. Saouma Rebuttal Testimony at 12-13, 34 fig.17; Ex. INT027, Dr. Saouma Pre-Filed Testimony at 33 fig.18(b).

822 Tr. at 387 (Sherman).

823 Tr. at 413 (Saouma).

824 Id.; Ex. INT032, Dr. Saouma Rebuttal Testimony at 34.

825 Ex. INT032, Dr. Saouma Rebuttal Testimony at 12-13.

826 Tr. at 392-93, 771 (Saouma).

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2. NextEra and Staff Responses NextEra witnesses testified that over the past eight years, Seabrook has shown a relatively steady rate of in-plane expansion, and that this, in turn, indicates that many areas at the facility are in the active portion of the sigmoid curve. 827 In particular, NextEra witness Mr.

Simons testified that NextEra measured an in-plane expansion of 0.04 mm/m (0.004%) per year as an average for all Tier 3 structures. 828 NextEra witnesses further testified that the through-thickness expansion rate in the Tier 3 structures was 0.2 mm/m (0.02%) per year, 829 with the most severe structure exhibiting 5.6 mm/m or 0.56% total through-thickness expansion. 830 Still, because NextEra monitors Tier 3 structures every six months, 831 its witnesses testified that even on the steep part of the curve, there are decades of margin before Seabrook structures might reach the SMP through-thickness expansion limit determined by the LSTP. 832 Therefore, NextEra witness Mr. Simons testified, a six-month interval is acceptable for monitoring the most ASR-affected areas at Seabrook. 833 827 Tr. at 399-400 (Simons). NextEra testified that, based on the qualitative descriptions in Dr.

Saoumas sigmoid curve, see Ex. INT027, Dr. Saouma Pre-Filed Testimony at 33 fig.18(b),

Seabrook is in the active phase/accelerating stage (i.e., stages iii, iv, and v). Tr. at 421-22 (Sherman).

828 Tr. at 415-16 (Simons).

829 Tr. at 685-86 (Simons), 695 (Bayrak). NextEra witness Mr. Carley testified that NextEra is seeing a rate, over a six-month period, of .02[%] increasing. We find this testimony somewhat unclear but interpret it to mean 0.2 mm/m (0.02%) through-thickness expansion per year, consistent with other testimony. Tr. at 1136 (Carley) 830 Ex. NER007 Ex. NER007, Seabrook [SMP] Manual Rev. 7 at B-14 tbl.2 (non-public); Tr. at 421 (Simons), 510 (Simons), 559 (Bagley), 1136 (Carley).

831 Ex. INT010, Original LAR at PDF 33 tbl.5.

832 Tr. at 415-16 (Simons), 713-14 (Collins); see Tr. at 695-96 (Bayrak) (stating that in the worst case . . . there is no reason to expect that you will be over the limit within the next six-month inspection); see also Tr. at 1126-27 (Lehman); Tr. at 691-92 (Buford) (stating that six-month monitoring frequency is a conservative option).

833 Tr. at 415-16 (Simons) (So clearly a six-month interval is completely acceptable for monitoring something that is going that slow.).

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Official Use Only Proprietary Information NextEra determined that the through-thickness acceptance limit may be reached within the licensed operating timeframe of Seabrook. 834 NextEra witnesses testified that, based on an expansion rate from the ISE document, 835 (which is also the Tier 3 through-thickness expansion rate at Seabrook), 836 a steady expansion rate of 0.2 mm/m (0.02%) per year will push Seabrook over the through-thickness expansion limit ( mm/m or  %) in . 837 NextEra witnesses stated that the Staff-imposed license condition to perform periodic expansion assessments includes an activity to evaluate the rate of ASR progression based on the observed expansion data and the margins to the acceptance criteria. 838 They further testified that [i]f evidence suggests that the monitoring intervals (or any other aspect of the SMP) at Seabrook are insufficient, the plant will evaluate the need for potential changes. 839 In addition, under the Staffs license condition, NextEra is required to conduct a Corroboration Study to determine whether expansion as determined by the modulus correlation matches actual expansion at the plant. 840 If the data do not match, NextEra is required to establish pre-instrument through-thickness, reassess total through-thickness (and volumetric) expansion against the acceptance criteria from the LSTP, and determine whether the structures [a]re operable and whether their licensing basis need[s] to be changed to address it. 841 834 Tr. at 416 (Simons).

835 Ex. NER012, ISE Structural Effects of [ASR] at 32 (non-public).

836 See supra note 829 and accompanying text.

837 See Ex. NER003, MPR Testimony, Proprietary Appendix at 2 tbl.3 n.3 (non-public).

838 Ex. NER001, MPR Testimony at 129; see Ex. INT024, Final SE at PDF 67-69.

839 Ex. NER001, MPR Testimony at 129.

840 Id. at 62, 120-21.

841 Tr. at 742 (Buford); see infra Part VIII.D.

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Official Use Only Proprietary Information With regard to the sigmoid curve, as indicated earlier, NextEra witness Mr. Sherman testified that it consists of a dormant period, an active period, and . . . a period where [ASR has]

petered out. 842 NextEra witnesses further testified that, according to modulus testing conducted by NextEra, Seabrook is in the active phase, which is the steep part of the curve beyond the inflection point. 843 In addition, NextEra witness Mr. Simons stated NextEra did not assume ASR progressed linearly, but instead that ASR in-plane expansion data from Seabrook has exhibited a relatively linear trend. 844 Staff witnesses testified that through-thickness expansion is measured starting at the relatively small in-plane expansion level of 1.0 mm/m (0.1%). 845 According to Staff witnesses, since it is measured every six months, even the fastest possible expansion could not exceed the expansion limits before the end of the next monitoring interval. 846 Further, Staff witness Dr.

Thomas noted that [t]here has been no case history where we [have] seen that ASR was the primary cause of the structural failure of collapse and therefore the risk related to ASR is relatively low, provided it's monitored and managed. 847 From this, Staff witness Mr. Lehman testified that where Seabrook falls on the sigmoid curve had no bearing on [the Staffs]

reasonable assurance determination. 848 NextEra witnesses testified, however, that the only need for understanding [the] rate of expansion at Seabrook is validation that the monitoring frequency is sufficient, and NextEra is using in-situ monitoring for this purpose. 849 842 Tr. at 387 (Sherman).

843 Tr. at 389-90 (Sherman); Tr. at 399-400, 415 (Simons).

844 Tr. at 399 (Simons).

845 Ex. NRC001-R, Staff Testimony at 45.

846 Tr. at 420 (Buford), 1122-24 (Buford).

847 Tr. at 1115 (Thomas).

848 Tr. at 1122-23 (Lehman).

849 Ex. NER001, MPR Testimony at 152.

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3. Findings of Fact and Board Analysis Based on the preponderance of the evidence in the record before us regarding the ASR monitoring interval for Tier 3 areas, the Board finds that the ASR monitoring intervals under the SMP fail to provide reasonable assurance in accordance with 10 C.F.R. §§ 50.40(a) and 50.57(a) that operation of Seabrook Unit 1 will not endanger the health and safety of the public.

Specifically, NextEra has not shown by a preponderance of the evidence that the current SMP can effectively account for an increase in the rate of ASR expansion, especially when NextEras own data indicates the SMP through-thickness expansion limit may be reached in . 850 We find action must be taken by NextEra well before the through-thickness expansion limit is reached. Since the license renewal authorizes operation until March 15, 2050, the Board finds that NextEra must establish a tangible mechanism that will detect an increased expansion rate and timely implement more frequent monitoring intervals, if necessary, because of an increased expansion rate.

By NextEras own admission, the through-thickness expansion acceptance limit will be exceeded in , with additional years of licensed operation. 851 By our calculations, 852 based on the most severe through-thickness cracking in the Tier 3 areas (5.6 mm/m or 0.56%)

and assuming a steady expansion rate of 0.2 mm/m or 0.02% as observed at Seabrook Unit 1, 853 in 2050 the maximum through-thickness expansion will be 12.4 mm/m (1.24%). This is mm/m (  %) above the expansion limit. In fact, by our calculation, the mm/m (  %)

850 See Ex. NER003, MPR Testimony, Proprietary Appendix at 2 tbl.3 n.3 (non-public).

851 Id. (non-public).

852 We assumed that the most severe cracking in Tier 3 (5.6 mm/m or 0.56%) areas was measured in 2016, when through-thickness expansion monitoring began, see Ex. NER001, MPR Testimony at 126, and that there would be 0.2 mm/m (0.02%) of expansion per year throughout the remaining operating period (i.e., 2016 to 2050).

853 NextEra witnesses further testified that the through-thickness expansion rate in the Tier 3 structures was 0.2 mm/m (0.02%) per year. Tr. at 685-86 (Simons), 695 (Bayrak).

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Official Use Only Proprietary Information through-thickness expansion acceptance limit may be reached in , with years of licensed operation remaining. 854 If in fact the expansion rate were to increase 20% to 0.24 mm/m (0.024%) per year, then the through-thickness expansion acceptance limit would be reached by . However, even without considering that the expansion rate may increase, a steady expansion rate will put NextEra beyond the acceptance limit within its licensed operating timeframe. We also note that the ISE document states that ASR does not expand uniformly within a given structure, adding another variable to future ASR expansion. 855 The Board finds that there is no conclusive evidence as to whether the through-thickness expansion rate will or will not accelerate during the next thirty years. The question turns in large part on where Seabrooks concrete is on the sigmoid curve that represents the typical path of ASR expansion. 856 While NextEra witnesses testified that Seabrooks concrete is already on the active/steep part of the sigmoid curve, 857 Dr.

Saouma testified that Seabrook is most likely in the very early slower phase, but the rate of expansion will accelerate at some point. 858 Through-thickness expansion monitoring only began in 2016, 859 and the Board lacks data sufficient to demonstrate that NextEra knows where it is on the sigmoid curve. NextEra witness Mr. Sherman testified that Seabrook concrete is on the active part of the curve based on elastic modulus testing and petrography. 860 Dr. Saouma responded, however, that NextEras method is not yet mature enough to be able to perform a 854 We used the following equation: ( x 0.2 mm/m) + 5.6 mm/m = m/m. years from 2016 is .

855 Ex. NER012, ISE Structural Effects of [ASR] at 31 (non-public).

856 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 32 fig.18.

857 Tr. at 399 (Simons).

858 Ex. INT032, Dr. Saouma Rebuttal Testimony at 13.

859 Ex. NER001, MPR Testimony at 126.

860 Tr. at 387-90 (Sherman).

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Official Use Only Proprietary Information quantifiable assessment of expansion based on . . . the change of elastic [modulus]. 861 The Board therefore finds that the position of Seabrook concrete on the sigmoid curve is uncertain.

The Board further finds, given that the expansion rate may increase as Dr. Saouma claims, that there is a significant risk that the current six-month monitoring frequency for Tier 3 areas may prove inadequate over the thirty years of licensed operation. The Staff testified that, in terms of its regulatory review, there really wasnt a requirement to identify where the plant is on the sigmoid curve as long as the inspection frequencies were frequent enough to capture expansion prior to hitting the limits. 862 Staff witnesses noted that the expansion rate could increase 1,000% in six months in the location with the highest through-thickness expansion (5.6 mm/m or 0.56%) and still be well below the expansion limits. 863 That is true at present, but reasonable assurance requires that the six-month monitoring interval provide adequate protection for the remaining thirty-year period of licensed operation. As explained above, the mm/m (  %) through-thickness expansion acceptance limit will likely be reached during the thirty-year period of licensed operation, at least in the most degraded areas. As the total level of expansion in a degraded area approaches the expansion limit, a smaller increase in the expansion rate will be sufficient to push the total expansion over the limit before the next inspection. Thus, the risk will increase that the current six-month monitoring frequency for Tier 3 areas will not comply with the Staffs requirement that testing frequencies are short enough that there isnt the potential for structural loss of function in between the inspection intervals. 864 Moreover, the sigmoid curve indicates that the expansion rate may increase over time, as Dr.

861 Tr. at 393 (Saouma).

862 Tr. at 420 (Buford).

863 Ex. NRC091, Staff Response to Ex. INT051-R at 5.

864 Tr. at 1122 (Buford).

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Official Use Only Proprietary Information Saouma testified, making it more likely that the six-month monitoring interval will not be frequent enough to capture expansion prior to reaching the limit.

The Board disagrees with NextEra and the Staff that the six-month interval for Tier 3 areas is the most stringent identified in the public literature. NextEra witnesses testified that the six-month monitoring interval reflects the most frequent interval recommended by the FHWA. 865 The Staff emphasized that six months is the most frequent monitoring interval it is aware of. 866 However, application of the ISE document, which NextEra and the Staff have cited as authoritative on other issues, 867 would likely have resulted in more frequent monitoring for Seabrook. The ISE document classifies structures in different categories based on an expansion index, the risk of failure, the site environment, and [r]einforcement detailing class. 868 The detailed inspections and monitoring of cracks in ASR-affected structures proceeds according to the degradation categories:

(i) Category A (Very Severe) - Monitored every (1) month (ii) Category B (Severe) - Monitored every two (2) months (iii) Category C (Moderate) - Monitored every four (4) months (iv) Category D (Mild) - Monitored every twelve (12) months 869 865 Ex. NER001, MPR Testimony at 128.

866 Tr. at 420 (Buford) (So six months is about the most frequent that in my knowledge for any aging mechanism, ASR included, that would -- I dont know of any program that would look at something more frequently than that.).

867 Ex. NER001, MPR Testimony at 16, 39, 41, 45, 54, 82, 89, 122, 128, 137; Ex. NRC091, Staff Response to Ex. INT051-R at 4-5; NRC Staffs Supp. Proposed Findings of Fact and Conclusions of Law at 3 n.16, 7 n.40.

868 Ex. NER012, ISE Structural Effects of [ASR] at 20 tbl.5 (non-public).

869 Id. at 30-31, 31 tbl.7 (non-public).

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Official Use Only Proprietary Information Unless the Seabrook structures with Tier 3 expansion would be classified in Category D, which seems unlikely, 870 the initial monitoring interval for Seabrook seismic Category I structures would have been less than six months. 871 The Commission indicated that the Board should consider whether the inspection intervals are sufficiently protective of public health and safety and whether the maintenance rule [10 C.F.R. § 50.65(a)(1)] affects this inquiry. 872 The maintenance rule directs licensees to monitor the performance or condition of structures, systems, or components, against licensee-established goals, in a manner sufficient to provide reasonable assurance that these structures, systems, and components . . . are capable of fulfilling their intended functions. 873 Having found that the six-month inspection interval may not be sufficiently protective for the remaining period of licensed operation, we consider whether NextEras guidance for implementing the maintenance rule alters that conclusion.

NextEras SMP states that it provides guidance for the conduct of the structural condition monitoring program to meet the requirements of [the maintenance rule]. 874 The SMP, however, lacks any requirement that NextEra management timely evaluate the need for more frequent monitoring intervals if it detects a significant increase in the ASR expansion rate or otherwise detects the potential for structural loss of function in between the inspection 870 A Category D structure must either be located in a dry environment or the consequence of structural failure must be slight. Id. at 20 tbl.5 (non-public). It is also hard to say Seabrook structures would be classified in Category A (Very Severe) or B (Severe) because those categories involve remedial work and/or load restrictions. Id. at 30 (non-public).

871 The ISE document permits inspection intervals for severity ratings C and D to be relaxed from 4 and 12 months, respectively, once trends for a structure have been established and moisture conditions are stable. Id. Addendum at 3 of 5 (non-public).

872 CLI-18-4, 87 NRC at 110 n.152.

873 10 C.F.R. § 50.65(a)(1).

874 Ex. NER007, Seabrook [SMP] Manual Rev. 7 at 1-1.1 (citing 10 C.F.R. § 50.65) (non-public).

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Official Use Only Proprietary Information intervals. 875 The SMP states that Follow-Up and Interim inspections may be performed in addition to the required 6-month or 30-month frequency inspections, but any such action is entirely at the discretion of the engineer. 876 The SMP provides no guidance as to how the discretion is to be exercised.

In the absence of evidence to the contrary, NRC does not presume that a licensee will violate agency regulations whenever the opportunity arises. 877 The Board makes no such presumption here. The problem with the SMP is the lack of any specific directive as to when additional inspections must be performed. This creates a reasonable possibility of a violation of the maintenance rules requirement that NextEra monitor the condition of Seabrook seismic Category I structures so as to provide reasonable assurance that those structures remain capable of fulfilling their intended functions for the period of licensed operation. 878 Apart from the SMP, NextEra witnesses testified that the Staffs license condition to perform periodic expansion assessments will require evaluation of the monitoring intervals. 879 The condition requires that if NextEras projections of future expansion indicate that the limits may be exceeded prior to the next periodic check, NextEra should further investigate the location(s) in question or develop contingency plans for extending the expansion limit (e.g.,

supplemental testing). 880 Thus, NextEra may avoid investigating the location of concern by developing plans for supplemental testing to increase the expansion limits, presumably by a 875 Tr. at 1122 (Buford).

876 Ex. NER007, Seabrook [SMP] Manual Rev. 7 at 3-1.10 (non-public).

877 See Private Fuel Storage, L.L.C. (Independent Spent Fuel Storage Installation), CLI-01-9, 53 NRC 232, 235 (2001). The Board makes no such presumption. The issue is the vagueness of the programmatic actions to be taken. The result could be an inadvertent violation of the maintenance rule.

878 10 C.F.R. § 50.65(a)(1).

879 Ex. NER001, MPR Testimony at 129.

880 Ex. INT019-R, MPR-4273 at B-2 to -3 (emphasis added); see Ex. INT024, Final SE at PDF 68-69.

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Official Use Only Proprietary Information testing program similar to the LSTP that could take years to create and implement. NextEra witnesses also testified that the plant will evaluate the need for potential changes [i]f evidence suggests that the monitoring intervals . . . at Seabrook are insufficient, 881 but they failed to identify any provision of the SMP or other NextEra document requiring such action.

Thus, the Board finds the SMP and the Staffs license condition inadequate to fulfill the maintenance rules directive that a licensee monitor the condition of its structures in a manner sufficient to provide reasonable assurance that these structures . . . are capable of fulfilling their intended functions. 882 To remedy this deficiency, the Board imposes the following license condition:

If the ASR expansion rate in any area of a Seabrook seismic Category I structure significantly exceeds 0.2 mm/m (0.02%) through-thickness expansion per year, NextEras Management will perform an engineering evaluation focused on the continued suitability of the six-month monitoring interval for Tier 3 areas. If the engineering evaluation concludes that more frequent monitoring is necessary, it shall be implemented under the SMP. 883 As stated above, NextEra admitted that the SMP through-thickness expansion acceptance limit may be exceeded in , even though there will be five additional years of licensed Seabrook operations. 884 This in itself requires NextEra to ensure the adequacy of its monitoring frequencies so that it will capture any deleterious increase in concrete expansion rates. Therefore, to provide reasonable assurance of adequate protection of public health and safety, the Board imposes the above license condition in order to ensure adequate ASR monitoring frequencies at Seabrook Unit 1.

881 Ex. NER001, MPR Testimony at 129.

882 10 C.F.R. § 50.65(a)(1).

883 Ex. NER007, Seabrook [SMP] Manual Rev. 7 at 3-1.10 (non-public).

884 Id. (non-public).

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Official Use Only Proprietary Information C. Accelerated Expansion Tests and Alternative Methodologies C-10 argued NextEra should have performed an accelerated expansion test. 885 An accelerated expansion test is a procedure that measures the ultimate potential for ASR expansion of a concrete sample. 886

1. Motion in Limine NextEra argued Dr. Saoumas testimony on alternative methodologies, such as conducting accelerated expansion tests 887 and using probabilistic based analyses, 888 should be excluded from the evidentiary record. 889 NextEra asserted that we denied admission of Contention G for attempting to prescribe a specific methodology, rather than address the adequacy of the chosen methodologies, 890 and therefore Dr. Saoumas attempts to prescribe specific methodologies are irrelevant and immaterial. 891 NextEra argued the mere presentation of an alternative method of regulatory compliance is irrelevant to the question . . . whether the method presented by the applicant satisfies regulatory requirements. 892 Therefore, NextEra seeks to exclude Dr. Saoumas testimony insofar as it discusses alternative methodologies, 885 C-10 Rebuttal SOP at 4; Ex. INT027, Dr. Saouma Pre-Filed Testimony at 32-33.

886 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 32 (ASR can be accelerated by storing

[Seabrook concrete] cores at temperatures ranging from 38 to 60 deg C. Small disks are glued on the cores, the cores are then placed in a container, and the container in a so called reactor which is heated to the right temperature, . . . . The cores are periodically extracted, and the elongation is measured with a so-called [Differential Electrical Mobility Classifier] instrument between the disks).

887 Ex. INT001-R, Dr. Saouma Pre-Filed Testimony §§ C.2.1, C.5, C.6, C.8, C.11 (non-public);

Ex. INT027, Dr. Saouma Pre-Filed Testimony §§ C.2.1, C.5, C.6, C.8, C.11; see Tr. at 378-79 (Saouma).

888 Ex. INT027, Dr. Saouma Pre-Filed Testimony § C.3.4.1.1.

889 NextEra MIL 2 at 10-12.

890 LBP-17-7, 86 NRC at 133-35.

891 NextEra MIL 2 at 10-12.

892 Id. at 10 (emphasis omitted).

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Official Use Only Proprietary Information including general references to a probabilistic based method, accelerated expansion tests, detailed petrographic stud[ies], 893 ultrasonic pulse echo, ultrasonic pulse velocity, 894 impact-echo, 895 acoustic emission, 896 RH/capacitance probe, wood stick, microwave technique: GPR, microwave technique: TDR, and microwave technique: open-ended coaxial probe. 897 The Staff similarly argued that consideration of alternative techniques is beyond the scope of its review of NextEras license amendment request because the Staffs responsibility is to ensure that the applicant is guided by the considerations that govern the issuance of the initial licenses. 898 Thus, the Staff asserted, any argument requesting an alternative approach is outside the scope of the proceeding. 899 In opposing NextEras Motion in Limine, C-10 claimed that Dr. Saoumas arguments concerning alternative compliance methodologies are properly before the Board. 900 C-10 maintained that Dr. Saouma is not stating that there are better alternatives, but rather that his testimony demonstrates the inadequacy of the methods used by NextEra by comparing it to more effective methods. 901 893 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 5, 20, 31, 32, 35-36; id. at 31 (advocating for the use of petrographic damage rating index (DRI)); see Ex. INT040, Assessment of ASR Using DRI at 90 (non-public).

894 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 35-36.

895 Id.

896 Id.; Tr. at 1150-51 (Saouma).

897 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 35-36.

898 See NRC Staff SOP at 47 (citing 10 C.F.R. § 50.92(a)). The Staff further underscored that it is not their responsibility to determine whether the request could be achieved in some other, arguably better, manner[.] Id.

899 Id. at 47-48.

900 C-10 Opp. to MIL 2 at 6-9.

901 Id. at 8-9.

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Official Use Only Proprietary Information We hold that the need to conduct accelerated expansion tests is rooted in a lack of representativeness and invokes the issue regarding the adequacy of monitoring intervals that we found admissible in Contention H. The testimony is therefore material and relevant to the reformulated contention. However, regarding a probabilistic-based method and Dr. Saoumas list of alternative methodologies to using CCI, 902 since we have found the use of the CCI acceptable subject to our license condition, 903 we need not consider the relevancy or materiality of the listed alternatives to CCI.

Dr. Saouma suggested three main reasons for conducting accelerated expansion tests:

to determine (1) a technical basis for the inspection intervals; (2) Seabrooks location on the sigmoid curve; and (3) the ultimate potential for ASR expansion. 904 Both the monitoring intervals and the overall issue of representativeness are implicated in C-10s assertions that an accelerated expansion test should be conducted. With regard to representativeness, Dr.

Saouma testified that [a]ccelerated expansion tests would have allowed a comparison to determine the extent to which the Seabrook concrete and the [LSTP] concrete differed. 905 Thus, one purpose of accelerated expansion tests is to confirm that the LSTP concrete is, or is not, representative of Seabrook. Dr. Saouma also stated that accelerated expansion tests can provide information to help determine where Seabrook is on the sigmoid curve. 906 We find that Seabrooks location on the sigmoid curve would inform the adequacy of monitoring intervals, a topic within the scope of this proceeding. Contention H, which we found admissible but limited to the appropriate length of monitoring intervals[,] is implicated in C-10s testimony concerning 902 See supra notes 893-897 and accompanying text.

903 See supra Part VIII.A.2.d.

904 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 32-33; Tr. at 386, 415 (Saouma).

905 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 10.

906 Id. at 32-33.

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Official Use Only Proprietary Information accelerated expansion tests. 907 Therefore, contrary to NextEras argument, C-10 did not assert the need for an accelerated expansion test as a mere presentation of an alternative method of regulatory compliance 908 but rather to probe the adequacy of two components of the reformulated contention with its testimony.

A key inquiry of this proceeding is whether the proposed monitoring intervals are adequate to capture ASR expansion at Seabrook, and that adequacy is based largely on whether the LSTP is sufficiently representative of Seabrook. 909 As such, although NextEra may have indicated a tenuous relationship between accelerated expansion tests and inadmissible Contention G, there are two connections between accelerated expansion tests and the reformulated contentionrepresentativeness and the adequacy of ASR monitoring intervals.

Therefore, we hold the testimony surrounding accelerated expansion tests is both material and relevant to resolving the reformulated contention, and we deny NextEras Motion in Limine regarding accelerated expansion tests.

We also find no merit in NextEras argument that testimony concerning accelerated expansion tests should be excluded on the same grounds that we excluded Contention G. 910 Contrary to NextEras assertions, we did not reject Contention G merely because it involved an alternative methodology, but because it would have required testing to the point of failure, or the tipping point, which would have provided less conservative expansion limits than those in the LAR. 911 The accelerated expansion tests proposed by Dr. Saouma, however, would not 907 LBP-17-7, 86 NRC at 125.

908 NextEra MIL 2 at 10.

909 LBP-17-7, 86 NRC at 122-23.

910 Id. at 134-35.

911 See id. at 135 (holding that Contention G failed to raise a material issue because the current ASR levels at Seabrook and the LAR acceptance criteria are bounded by the test program, such that the tipping point would not be reached before the acceptance criteria are exceeded). As

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Official Use Only Proprietary Information necessarily propose less conservative monitoring intervals than those in the LAR; they might result in more frequent monitoring intervals than proposed by NextEra. This is one instance in which it is not only appropriate, but also necessary to consider alternative tests proposed by C-10 to determine whether the LAR provides adequate protection of public health and safety. 912 Thus, previously declining to admit Contention G in no way renders out of scope C-10s proffered testimony on accelerated expansion tests.

Concerning petrographic damage rating index (DRI), Dr. Saouma stated that NextEra prematurely ruled out the applicability of petrographic DRI and that petrographic analysis should be conducted in conjunction with CCI. 913 In addition, Dr. Saouma proffered several alternatives to CCI, as noted above. 914 NextEra argued that these are alternative compliance methods that should be excluded from the record. 915 We need not address here whether these alternatives to CCI should be excluded, because, as elaborated above, we find that using CCI as a monitoring technique is sufficient when analyzed with the additional assurances provided by our license condition. 916 Turning to the probabilistic-based methods suggested by Dr. Saouma, 917 we grant NextEras Motion in Limine. Dr. Saouma advocated for the use of probabilistic-based methods, the Staff argued, the LAR is structured such that the limits on the Seabrook concrete are more conservative than the tipping point of the concrete[.] Id. at 134.

912 See Long Island Lighting Co. (Shoreham Nuclear Power Station, Unit 1), LBP-88-13, 27 NRC 509, 548-49, affd in part, vacated in part, and remanded, ALAB-905, 28 NRC 515 (1988)

(reviewing alternative compliance methods to determine reasonable assurance); see also Palisades, CLI-15-22, 82 NRC at 317-18 (noting alternative methods can demonstrate reasonable assurance).

913 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 20, 31.

914 See supra notes 893-897 and accompanying text.

915 NextEra MIL 2 at 10-12.

916 See supra Part VIII.A.2.d.

917 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 29-31. Dr. Saouma stated [p]robabilistic risk (or safety) assessment (PRA) consists of an analysis of the operations of a particular nuclear power plant (NPP), which focuses on the failures or faults that can occur to

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Official Use Only Proprietary Information in lieu of NextEras code-based approach. 918 Although such methods could be material under GDC 1, which permits supplementation of general codes and standards, 919 we need not address them here for two reasons. First, they were not addressed in C-10s Petition. Second, unlike accelerated expansion tests, they are unrelated to any of the bases of the reformulated contention, and therefore do not fall within the scope of this proceeding.

We also exclude all of C-10s proffered testimony referring to the methodologies used at other structures and power plants. 920 Such testimony is unrelated to the representativeness of the LSTP, and unrelated to Seabrook in general. Therefore, with regard to testimony comparing ASR monitoring methods used at Seabrook to other structures and power plants, we grant NextEras Motion in Limine and decline to address such testimony. 921

2. C-10s Prima Facie Case Dr. Saouma testified that an accelerated expansion test is an easy test 922 that NextEra should have performed to gauge where Seabrook structures are on the sigmoid curve. 923 Such a test creates a plot of ASR expansion versus time for the concrete test sample. 924 Dr. Saouma stated that:

components, systems or structures, and that can lead to damage and ultimately to the release of radioactive material, especially the fission products and actinides within the reactor fuel. Id.

at 30.

918 See generally id.; Ex. INT032, Dr. Saouma Rebuttal Testimony.

919 Where generally recognized codes and standards are used, they shall be identified and evaluated to determine their applicability, adequacy, and sufficiency and shall be supplemented or modified as necessary to assure a quality product in keeping with the required safety function. 10 C.F.R. pt. 50, app. A § I (emphasis added).

920 See Ex. INT027, Dr. Saouma Pre-Filed Testimony at 34; Ex. INT032, Dr. Saouma Rebuttal Testimony at 4-6.

921 NextEra MIL 2 at 10-12.

922 Tr. at 400 (Saouma).

923 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 32-33.

924 Id. at 32.

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Official Use Only Proprietary Information It is . . . problematic that FSEL failed to perform the accelerated expansion tests of Seabrook and [LSTP] concrete cores. Accelerated expansion tests would have allowed a comparison to determine the extent to which the Seabrook concrete and the [LSTP] concrete differed. As a result of FSELs failure to use identical concrete in [the LSTP], and its failure to conduct accelerated expansion tests, it is impossible to predict with any confidence the maximum expansion at Seabrook. Essentially, that figure is completely unknown. This is a significant problem that could have been easily avoided. 925 Additionally, Dr. Saouma testified that without conducting an accelerated expansion test, NextEra cannot determine the maximum likely degree of expansion. 926 Dr. Saouma stated that accelerated expansion tests are [t]he only way to assess the potential for future expansion. 927 In addition to accounting for maximum ASR expansion, Dr. Saouma testified that accelerated expansion tests account for the specific kinetic reactions of ASR. 928 Dr. Saouma asserted that the FHWA Report supports the assertion that accelerated expansion testing can determine the ultimate expansion of ASR. 929 Dr. Saouma also testified that an accelerated expansion test could provide a technical basis for the inspection intervals in the LAR, in addition to determining the ultimate ASR expansion. 930 In addition to asserting NextEra should conduct acceleration expansion tests, C-10 advocated developing calibrated numerical models. 931 Dr. Saouma testified that periodic 925 Id. at 10.

926 Id. at 11.

927 Tr. at 505-06 (Saouma); Tr. at 772 (Saouma).

928 Ex. INT032, Dr. Saouma Rebuttal Testimony at 13 (Kinetics can be assessed through accelerated expansion tests as described in EPRI Report 3002013192, Exhibit NER01[7].

(citing Ex. NER017, EPRI Report 3002013192, Evaluation of Laboratory Tests to Detect Up-to-Date Expansion and Remaining Expansion in Concrete Structures Affected by Alkali-Silica Reaction (Oct. 15, 2018) at 2-1 [hereinafter Ex. NER017, EPRI Report] (non-public))).

929 Tr. at 325-26 (Saouma); Ex. NER013, FHWA Report at 26-27.

930 Tr. at 385-86 (Saouma).

931 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 32-36; Ex. INT032, Dr. Saouma Rebuttal Testimony at 8-10; Tr. at 306, 310-11, 839-40 (Saouma).

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Official Use Only Proprietary Information damage rating index (DRI) measurements, detailed petrographic studies, and modern computational methods should be developed since they are demonstrably effective[.] 932 Dr. Saoumas testimony provides a plausible analysis to support his opinion. C-10 has therefore satisfied its burden to present a prima facie case.

3. NextEra and Staff Responses NextEra witnesses testified that NextEra did not need to determine ultimate expansion because its methods focused on determining accurate monitoring frequencies and acceptance limits. 933 NextEra witness Dr. Bolourchi indicated that monitoring structures based on threshold factors does not require the evaluation of the rate of ASR growth because threshold factors are insensitive to the rate of ASR growth. 934 NextEra witnesses testified that accelerated expansion tests would not provide any useful data for its chosen monitoring programs. For example, NextEra witness Mr. Sherman testified that using an artificially high temperature and 100% relative humidity would result in data that bear no relationship to the parameters of the SMP. 935 Additionally, NextEra witness Mr. Bagley testified that, depending on the method used, accelerated expansion tests are not representative of the actual condition of the aggregate . . . [and such tests are conducted]

932 Ex. INT032, Dr. Saouma Rebuttal Testimony at 9.

933 Ex. NER001, MPR Testimony at 129, 137-38; id. at 152 ([T]he only need for understanding

[the] rate of expansion at Seabrook is validation that the monitoring frequency is sufficient, and NextEra is using in-situ monitoring for this purpose.).

934 See Tr. at 937-38 (Bolourchi).

935 Tr. at 377-78 (Sherman) (One of the accelerated tests that you do exposes it to large amounts of alkali in high temperature. The idea behind that is it says how much might this stone react if everything else is provided to it. We know thats not the case. Theres not an infinite source of alkali at the plant. All thats there is what was built into it. The other test says if I keep it at a high temperature and 100[%] relative humidity, water dripping off of it, where it might go somewhere down the road. We dont have high temperatures and 100[%] humidity.

So I have a data point, but I dont know what it means.).

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Official Use Only Proprietary Information outside of [their] structural context. 936 Therefore, Mr. Bagley concluded, the accelerated expansion tests that C-10 suggested would not be directly relatable back to whats in the plant. 937 Further, unconfined concrete would be used for an accelerated expansion test, which is not representative of conditions at Seabrook. 938 In arguing the non-representative nature of accelerated expansion tests, NextEra witness Dr. Bayrak emphasized that the ultimate expansion data in such a test may be several orders of magnitude greater than actual conditions. 939 Dr. Bayrak further stressed that the data serves absolutely no purpose 940 and merely provides a worst case scenario. 941 NextEra witness Mr. Carley asserted that an accelerated expansion test is not easy, as suggested by Dr. Saouma, 942 but rather a very tedious, expensive, [and] difficult process that could damage the structural rebar. 943 For example, an accelerated expansion test would require NextEra to extract 4-inch cores, which is roughly the spacing between the rebar in Seabrook structures. 944 NextEra has already extracted in-situ cores to determine through-thickness expansion to date, even though it found the extraction process to be a time consuming, very difficult process. 945 NextEra is obligated, as part of the license condition 936 Tr. at 379-80 (Bagley).

937 Tr. at 380 (Bagley).

938 Tr. at 380-81 (Sherman).

939 Tr. at 781-82 (Bayrak).

940 Tr. at 782 (Bayrak).

941 Tr. at 781 (Bayrak).

942 Tr. at 400 (Saouma).

943 Tr. at 381 (Carley).

944 Id.

945 Id.

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Official Use Only Proprietary Information Corroboration Study 946 to extract cores at set intervals to ensure the LSTP results remain valid as model for assessing ASR expansion at Seabrook. 947 NextEra witnesses further testified that NextEra conducts trending analyses and extrapolates actual data from the plant to determine whether Seabrook structures will remain within the expansion limits, and as a consequence, NextEra does not need to identify ultimate ASR expansion in an artificial setting conducive to ASR expansion. 948 NextEra witness Mr.

Carley testified that NextEra determined through-thickness expansion to date by extracting over 200 in-situ cores and then extrapolating the data to assess long-term expansion limits. 949 C-10 disputed NextEras claim that once cores are removed from the structures, they are no longer representative. Dr. Saouma testified that NextEra tested the 200 extracted cores for compressive strength and elastic modulus, notwithstanding representativeness issues. 950 Thus, Dr. Saouma stated that NextEras position is hypocritical because NextEra conducted other analyses on the extracted cores and deemed the resulting data representative. 951 From this, Dr.

Saouma stated that if NextEra used the cores to gather pertinent data for compressive strength and elastic modulus, it can also use the same cores in an accelerated expansion test. 952 According to NextEra witness Mr. Carley, however, the process of determining the elastic modulus destroys the cores which renders them unavailable for use in accelerated 946 Ex. INT024, Final SE at PDF 67-69; Ex. NER001, MPR Testimony at 61-62.

947 Tr. at 381-82 (Carley) (We have committed to do additional cores for [the] [C]orroboration

[S]tudy in the future. But just to take cores for doing an accelerated test, and as you heard, that probably is not going to provide value to the method we have chosen was a route that we have chosen not to take.).

948 Tr. at 380-81 (Sherman); Ex. NER001, MPR Testimony at 129.

949 Tr. at 381 (Carley).

950 Tr. at 384-85 (Saouma).

951 Id.

952 Id.

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Official Use Only Proprietary Information expansion tests. 953 With the original cores destroyed, further core sampling would be required, resulting in additional destructive testing to Seabrooks structures. 954 The Staff agreed with NextEra that an accelerated expansion test is not required, arguing that C-10 failed to establish why understanding ultimate ASR expansion is a safety concern. 955 Staff witnesses also testified that NextEras approach identified reasonable and justifiable structure-specific expansion limits[] which account for potential future expansion[.] 956 Staff witnesses stated that [k]nowing the ultimate expansion is not relevant to the approach chosen by NextEra because the ultimate expansion is irrelevant as long as the structures are monitored and remain below the limits. 957 NextEra conducted residual reactivity testing to determine whether Seabrook is prone to future ASR expansion or whether the reaction has been exhausted. In 2012, NextEra performed residual reactivity testing per ASTM C 1260, which is a method intended to test an aggregate source for potential reactivity before new construction. 958 NextEra obtained the aggregate from cores removed from existing Seabrook structures. 959 Thereafter, NextEra used the aggregate to:

[F]abricate a mortar bar and submerged [it] in a hot sodium hydroxide solution to accelerate expansion. Per ASTM C 1260, the aggregate is determined to be reactive if an expansion of greater than [1.0 mm/m (0.1%)] is observed. The test results showed an expansion of over [7.0 mm/m (0.7%)] with no sign of plateauing after 103 days, indicating that Seabrook is susceptible to future expansion. Accordingly, NextEra conservatively assume[d] that ASR could 953 Tr. at 382 (Carley).

954 Tr. at 381-82 (Carley).

955 Ex. NRC001-R, Staff Testimony at 71.

956 Id.

957 Id. at 71-72.

958 Ex. NER001, MPR Testimony at 137-38.

959 Id.

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Official Use Only Proprietary Information continue through the remainder of plant life and [that there is no] maximum bound on potential expansion. 960 NextEra also calculated that it expects to exceed the through-thickness expansion limit in the most severe area by . 961 NextEra concluded:

The quantitative results of the [ASTM C 1260] test were not useful because the composition and structural context of the mortar bar [is] vastly different than [that at] the plant. No further residual reactivity testing was performed, because there was (and still is) no further application for the results, given the assumption of unbounded potential ASR progression. 962 NextEra witnesses also addressed the question why NextEra did not perform reactivity testing on the LSTP specimens, indicating:

With respect to the LSTP specimens, reactivity testing was never performed because the information from this testing would not have been useful. The concrete mixture design was known, and was intentionally susceptible to ASR, so there was no need to confirm reactivity . . . . Even if the maximum possible expansion of the LSTP test specimens were known, it would not have affected interpretation of the results, which related structural performance to the measured expansion (regardless of the potential future expansion). 963 Responding to NextEras argument, Dr. Saouma stated that an accelerated expansion test could provide a technical basis for the inspection intervals in the LAR, in addition to determining the ultimate ASR expansion. 964 Further, he reiterated that NextEra must evaluate where it is on the sigmoid curve, and an accelerated expansion test is one way to do so. 965 As discussed above, NextEra witness Mr. Sherman testified that NextEra knows where it is on the sigmoid curve because both the petrography and elastic modulus indicate Seabrook is 960 Id. at 137; see Tr. at 1117-18 (Philip) ([Mortar bars are] small samples without the structural context in place.).

961 Ex. NER003, MPR Testimony, Proprietary Appendix at 2 tbl.3 n.3 (non-public).

962 Ex. NER001, MPR Testimony at 137.

963 Id. at 138.

964 Tr. at 385-86 (Saouma).

965 Tr. at 386, 415 (Saouma).

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Official Use Only Proprietary Information in the active phase of the curve. 966 According to Mr. Sherman, Seabrooks location on the sigmoid curve is continually monitored through the expansion monitoring with pins and through visual monitoring. 967 NextEra witness Mr. Bagley testified that the petrographic examinations done by SG&H, and then the rate monitoring that has been done over time [by the SMP],

provides the best estimate . . . for where the plant is on the [sigmoid] curve. 968

4. Findings of Fact and Board Analysis While C-10 recommends an alternative method for evaluating ASR at Seabrook, we conclude that NextEra has shown by a preponderance of the evidence that NextEras approach to measuring ASR and its structural impact provides reasonable assurance and does not require supplementation by an accelerated expansion test. C-10 has failed to demonstrate that the current method of in-situ monitoring against threshold limits established in the LSTP is insufficient and does not provide reasonable assurance that it will effectively monitor ASR.

a. Ultimate ASR Expansion/Representativeness NextEras chosen monitoring approach does not require a determination of the ultimate ASR expansion. A centerpiece of NextEras ASR monitoring program is its monitoring intervals, which vary depending on the severity of ASR degradation in a given structure. 969 As long as the monitoring intervals are sufficient (discussed supra Part VIII.B), there is no need to determine ultimate expansion. C-10 failed to proffer any evidence that would establish the need for an artificially high (likely by several orders of magnitude) expansion limit of the concrete. As NextEra witnesses testified, the only need for understanding [the] rate of expansion at 966 Tr. at 389-91 (Sherman).

967 Tr. at 391 (Sherman).

968 Tr. at 401 (Bagley).

969 See Ex. INT010, Original LAR at PDF 65-66.

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Official Use Only Proprietary Information Seabrook is validation that the monitoring frequency is sufficient, and NextEra is using in-situ monitoring for this purpose. 970 We also emphasize that NextEra determined the expansion potential of Seabrook concrete by using a reactivity test. 971 With the reactivity test, NextEra determined that the expansion potential of actual Seabrook concrete to be greater than 7.0 mm/m (0.7%), which means that the expansion may exceed the threshold limits provided in the LAR and monitored in the SMP. 972 Therefore, NextEra assumes that in-situ monitoring will continue for the licensing term and that the ultimate expansion potential will exceed the threshold limits established by the LSTP. 973 NextEra indicated it expects to exceed the through-thickness expansion limit in the most severe areas by . 974 Thus, NextEra acknowledged that ASR will expand at Seabrook throughout the life of the plant and has incorporated those assumptions into the monitoring program accordingly.

Furthermore, we note that an accelerated expansion test is a destructive test.

Therefore, it must provide significant and useful data to justify its use. We find that an accelerated expansion test would not provide useful data regarding ultimate ASR expansion because NextEra assumes that ASR expansion will continue for the duration of the plants licensed operation, based on the expansion data from the reactivity test. 975 Regarding the use of accelerated expansion tests to confirm that LSTP concrete is, or is not, representative of Seabrook, the Board finds that because the concrete mixture design of the LSTP test specimens was made intentionally susceptible to ASR, its reactivity as measured 970 Ex. NER001, MPR Testimony at 152.

971 Id. at 137-38.

972 Id. at 137.

973 Id.

974 Ex. NER003, MPR Testimony, Proprietary Appendix at 2 tbl.3 n.3 (non-public).

975 Ex. NER001, MPR Testimony at 137.

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Official Use Only Proprietary Information by an accelerated expansion test would be different from the reactivity of the Seabrook concrete by design. As a result of this, the performance of accelerated expansion tests would not provide useful information regarding whether the LSTP concrete is representative of the Seabrook concrete.

b. Monitoring Intervals and Sigmoid Curve Because NextEra assumes that ASR will expand for the duration of the licensing term, 976 NextEra will continuously monitor ASR-affected structures, with the most severely affected structures currently monitored every six months. 977 If the SMP indicates a significant increase in the expansion rate, NextEra will need to increase its monitoring frequency in accordance with the Boards license condition, an approach we have found sufficient to provide reasonable assurance of adequate protection of public health and safety, supra Part VIII.B.3. C-10 failed to explain how or why an accelerated expansion test would provide significant or useful data that otherwise could not be obtained by the monitoring program. We note that NextEra has already assumed it is in the active portion of the sigmoid curve 978 and that it is monitoring both the expansion and the rate of expansion. NextEra is in essence developing the expansion curve using actual plant data rather than a laboratory-based test Our review of the relevant record documents supports the conclusion that accelerated expansion tests are not necessary at Seabrook. Both the EPRI Report and the FHWA Report indicate that the best method to determine the rate of expansion for a given Seabrook structure is in-situ monitoring for expansion and deformation performed at selected frequencies. 979 The FHWA Report states that [t]he potential for further expansion due to ASR is a critical parameter 976 Id. at 137-38.

977 See Ex. INT010, Original LAR at PDF 65.

978 Tr. at 421-22 (Sherman).

979 See Ex. NER013, FHWA Report at 26-27; Ex. NER017, EPRI Report at 2-15 (non-public).

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Official Use Only Proprietary Information to consider when selecting the most appropriate remedial action(s) for concrete affected by ASR. 980 Further, the FHWA Report states that [c]urrent rates of expansion are best established from periodic or continuous in-situ monitoring of deformations, which can then be extrapolated for estimating the potential for future expansion. 981 However, that report continues, such a method may take two to three years to yield useful information[.] 982 The EPRI Report echoes the FHWA Reports conclusions that in-situ monitoring is an accurate method to monitor the ASR expansion. Specifically, the EPRI Report states that

[m]onitoring the deformation in the field is considered as the most accurate method for evaluating the current rate of expansion[.] 983 Consistent with the FHWA Report, the EPRI Report justifies this conclusion by demonstrating that deformation monitoring should be performed for at least [two] to [three] years to account for temperature and moisture variations in the field. 984 In recommending in-situ monitoring, the EPRI Report emphasized several drawbacks of laboratory tests such as accelerated expansion tests. 985 980 Ex. NER013, FHWA Report at 26.

981 Id.

982 Id. at 26-27 (However, in-situ monitoring will generally take a minimum of 2 and preferably 3 years to yield useful information, i.e., where permanent and cumulative deformation due to ASR could reliably be differentiated from reversible and cyclic movements related to mechanical (loading, traffic, operation conditions, etc.), thermal and climatic (daily and seasonal) variations.).

983 Ex. NER017, EPRI Report at 2-15 (citations omitted) (non-public).

984 Id. (non-public).

985 Id. at 2-17 (There may be difficulties in measuring the total ASR expansion in cores because the duration of these tests is not long enough to allow full consumption of reactive silica within the aggregates[;] Alkali leaching during the test underestimates the ASR expansion potential[;]

The stress condition in field structures is different from that of cores[;] The residual expansion measured from cores does not account for the effects of reinforcement and loading in field structures. The level of reinforcement and the direction of the reinforcement are key parameters governing the extent of expansion observed in the field and cannot be accounted for in laboratory testing[;] Inconsistent humidity condition during long-term testing (for example, 1-2 years) can cause variation in ASR expansion[;] Several cores must be taken from different locations and along different directions within structures to represent different conditions of

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Official Use Only Proprietary Information According to the EPRI Report, accelerated expansion tests, by themselves, are not reliable indicators of future ASR expansion because there are several significant variables. For instance, expansion tests on cores can provide only an indication on the future potential of ASR reaction (free residual expansion). 986 Instead of using accelerated expansion tests, the EPRI Report suggests a combination of testing and monitoring is necessary to predict the actual behavior of ASR-affected structures[.] 987 Additionally, the ISE document emphasizes that structural behavior, rather than the specific kinetic reaction of ASR, is the primary concern in measuring ASR. 988 The ISE document reaches this conclusion by emphasizing that there is not a uniform expansion rate within a given structure. 989 Stressing instead that there may be substantial differences because [s]ome pours [within one structure or wall] may show no apparent damage while others may be severely damaged by cracking. 990 As a result, the ISE document concluded measuring the structural [behavior] on site provides the best indication of rates of deterioration and when the rate of ASR damage is slowing. 991 The Board also agrees with NextEra that, because unconfined concrete would be used for an accelerated expansion test, such tests would not be representative of conditions at ASR. This requires careful investigation to select cores from the most and least affected zones.) (non-public).

986 Id. (non-public).

987 Id. (A combination of laboratory testing, structural monitoring (for instance, deformation, temperature, humidity, and confined stresses), and information from structures (for example, reinforcement detailing and boundary conditions) should be used to develop calibrated numerical models to predict the actual behavior of ASR-affected structures[.] (citations omitted)) (non-public).

988 Ex. NER012, ISE Structural Effects of [ASR] at 31 (non-public).

989 Id. (non-public).

990 Id. (non-public).

991 Id. (non-public).

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Official Use Only Proprietary Information Seabrook. Dr. Saouma stated in response that extracted cores were used for other tests. 992 This argument is unpersuasive. The fact that NextEra used extracted cores for other purposes does not make them representative for the purposes of accelerated expansion tests. Because the in-situ cores, after being subjected to accelerated expansion, would be unrepresentative of Seabrook concrete, we fail to see how that data could influence the monitoring intervals, which are based on actual data from the plant.

c. Threshold Expansion/Acceptance Limits We find no need to conduct an accelerated expansion test to indicate whether Seabrook structures will exceed the acceptance limits. NextEra conducted a reactivity test and concluded ASR would expand for the duration of the licensing term. 993 Also, NextEra calculated that the through-thickness expansion limit would be reached in , assuming linear ASR expansion. 994 Problems with non-representativeness aside, there is no need to perform a test to determine whether the acceptance limits will be exceeded when NextEra already assumes that the expansion limits likely will be reached during the licensing term. In effect, an accelerated expansion test cannot tell NextEra anything it does not already know with regard to the acceptance limits.

The primary goal of the Seabrook in-situ monitoring program in the SMP is to assure that the acceptance limits established under the LSTP, as documented in the LAR and implemented in the SMP, are not exceeded. 995 A preponderance of the evidence indicates that the use of 992 Tr. at 384-85 (Saouma).

993 Ex. NER001, MPR Testimony at 137-38.

994 Ex. NER003, MPR Testimony, Proprietary Appendix at 2 tbl.3 n.3 (non-public).

995 See Ex. NER007, Seabrook [SMP] Manual Rev. 7 at 1-1.1 (non-public); Ex. NER001, MPR Testimony at 128 ([T]he purpose of the SMPand any aging management programis to monitor the aging mechanism so that the plant can take action to address the condition before it continues outside of the licensing basis. The SMP at Seabrook fulfills this function by using a classical aging management approach to monitor parameters to specified acceptance criteria and take action prior to exceeding those criteria.).

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Official Use Only Proprietary Information periodic in-situ expansion monitoring, conducted under the SMP, is the best method to measure the current rates of expansion and, by extrapolation, the potential for future expansion according to the FHWA Report, which Dr. Saouma references in his hearing testimony. 996 The in-situ monitoring program at Seabrook will be in place for the duration of the licensing term, which is significantly longer than the minimum two or three years needed for such monitoring to account for natural cyclic variations. 997 While accelerated expansion testing might be a useful addition to the development of the calibrated numerical models discussed above, 998 it is not required, and there is no evidence indicating it would be helpful to support the in-situ monitoring approach selected by NextEra and described in the LAR. 999 Dr. Saouma testified that his other suggested methods (periodic [DRI]

measurements, detailed petrographic studies, and modern computational methods) are demonstrably effective. 1000 But C-10 proffered no other evidence demonstrating that NextEras in-situ monitoring is demonstrably ineffective. 1001 Although Dr. Saouma testified that his suggestions are not just a different way to do the job, 1002 the Board finds by a preponderance of the evidence that the best method of determining the current rate of expansion is in-situ monitoring of the structures. We therefore agree with the Staff and NextEra that there is no need to perform accelerated expansion tests in support of the SMP.

996 Ex. NER013, FHWA Report at 26.

997 Id. at 26-27.

998 See supra notes 931-932 and accompanying text.

999 See Ex. NER001, MPR Testimony at 137-38; Ex. NRC001-R, Staff Testimony at 71-72.

1000 Ex. INT032, Dr. Saouma Rebuttal Testimony at 9.

1001 Id.

1002 Id.

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Official Use Only Proprietary Information D. Corroboration Study The Corroboration Study forms the technical basis for the SMP. 1003 Simply described, when an extensometer is inserted into the Seabrook concrete according to the SMP guidelines to track future through-thickness expansion, NextEra needs to know the amount of expansion that has occurred from the time that the plant was constructed until the time that the extensometer is inserted. 1004 NextEra implemented a methodology for calculating initial expansion by using an empirical correlation developed during the LSTP. 1005 The methodology determines through-thickness expansion from the normalized elastic modulus. 1006 The latter is the ratio of the measured elastic modulus when the extensometer is installed to the elastic modulus twenty-eight days from original casting of the concrete during Seabrooks construction. 1007 Though the elastic modulus was not measured during plant construction, compressive strength was measured, and NextEra stated that the elastic modulus can be calculated from the compressive strength using the ACI 318-71 empirical formula. 1008 Although NextEra considered another approach for obtaining the original elastic modulus by extracting and measuring cores at representative ASR-free Seabrook locations, 1009 it decided instead to use the compressive strength methodology. 1010 1003 Tr. at 1012 (Buford).

1004 Ex. NER001, MPR Testimony at 121.

1005 Id. at 117-19.

1006 Id.

1007 Ex. INT018-R, MPR-4153, Rev. 3 at 3-4.

1008 Id. § 3.3.1; Ex. INT020, MPR-4153, Rev. 3 § 3.3.1 (non-public); Ex. NRC049, ACI 318-71 § 8.3 (non-public).

1009 Ex. INT018-R, MPR-4153, Rev. 3 at iv, § 4; Ex. INT020, MPR-4153, Rev. 3 at iv, § 4 (non-public).

1010 Tr. at 751 (Bagley).

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Official Use Only Proprietary Information Dr. Saouma challenged the Corroboration Study that NextEra is required to conduct to ensure that the through-thickness expansion of Seabrooks concrete can be derived from a measurement of the concretes elastic modulus in accordance with a correlation equation just as was done during the LSTP. 1011 Specifically, Dr. Saouma testified that the identified problems in the Corroboration Study are too great for it to be reliable. 1012 NextEra witnesses testified that the approach it adopted for the Corroboration Study is supported by the literature, which states that the elastic modulus decreases with the progression of ASR, and researchers have investigated this phenomenon quantitatively. 1013 In fact, NextEra quoted the EPRI Report as concluding that the modulus of elasticity is the best indicator for ASR progress. 1014 NextEra decided to use the LSTP data to produce its own correlation rather than rely on the literature in order to improve representativeness by utilizing specimens that ha[d] a reinforcement configuration . . . comparable to structures at Seabrook. 1015 Finally, NextEra asserted that it applied a reduction factor of to the normalized elastic modulus input, 1016 which increases the calculated effect of ASR degradation, causing the estimated through-thickness expansion to be higher than it would be if the reduction factor were not applied. According to NextEra witnesses, this approach rendered the revised correlation more conservative, since it reduces the margin to the acceptance criteria derived 1011 Tr. at 514-15, 771 (Saouma); Ex. INT028, Dr. Saouma Rebuttal Testimony at 36-41 (non-public); Ex. INT032, Dr. Saouma Rebuttal Testimony at 36-41; Ex. INT030-R, Dr. Saouma Supp. Rebuttal Testimony at 1-4.

1012 Ex. INT028, Dr. Saouma Rebuttal Testimony at 36-41 (non-public); Ex. INT032, Dr.

Saouma Rebuttal Testimony at 36-41; Ex. INT030-R, Dr. Saouma Supp. Rebuttal Testimony at 1-4.

1013 Ex. NER001, MPR Testimony at 118-19.

1014 Ex. NER017, EPRI Report at 4-1, 4-2 fig.4-1 (non-public).

1015 Ex. NER001, MPR Testimony at 118-19.

1016 Ex. INT018-R, MPR-4153, Rev. 3 § 4.2.2; Ex. INT020, MPR-4153, Rev. 3 § 4.2.2 (non-public).

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Official Use Only Proprietary Information from the LSTP. 1017 Thus, for the purpose of determining total through-thickness expansion at any future date after extensometer insertion, NextEra will use the sum of the calculated expansion from the time of construction until extensometer insertion using the revised modulus correlation and the future expansion as measured by the extensometer. 1018 NextEra witnesses provided the following description of the Corroboration Study:

The [C]orroboration [S]tudy will occur several years after installation of the extensometers to allow time for through-thickness expansion to occur.

Fundamentally, the approach for the [C]orroboration [S]tudy includes four steps:

(1) estimate pre-instrument expansion using the correlation when the extensometer is installed to establish a point of reference, (2) monitor through-thickness expansion using the extensometer as specified in the SMP, (3) after several years of monitoring, obtain another core from the same general vicinity and test for elastic modulus to re-determine through-thickness expansion, (4) compare the change in expansion from the original point of reference using the new elastic modulus data and the extensometer data. Successful corroboration would show comparable results using the two methods. At the time of the study, NextEra will obtain new cores from the vicinity of 20% of the extensometers. 1019 The Staff agreed with NextEras approach and imposed a license condition that requires the study to cover at least 20% of extensometer locations on ASR-affected structures. 1020 NextEra must complete the initial study no later than 2025 and a complete follow-up study 10 years thereafter. 1021 According to the Staff:

[I]f there is [an] indication that the LSTP results do not apply to Seabrook structures, then NextEra would be required to conduct prompt operability determinations to determine whether the structures remain operable or, if they do not, shut down the facility, as dictated by the facilitys technical specifications; these activities would be subject to NRC oversight. 1022 1017 Ex. NER001, MPR Testimony at 120; Ex. NER003, MPR Testimony, Proprietary Appendix at 9 fig.10 (non-public).

1018 Ex. NER001, MPR Testimony at 120.

1019 Id. at 121; see Ex. INT019, MPR-4273, app. C; Ex. INT021, MPR-4273 app. C (non-public).

1020 Ex. INT024, Final SE at PDF 68-69; Ex. NRC001-R, Staff Testimony at 43.

1021 Ex. INT024, Final SE at PDF 68-69.

1022 NRC Staffs Proposed Findings of Fact and Conclusions of Law at 25; see Tr. at 719-20 (Buford, Lehman), 739-42 (Buford), 1012 (Buford).

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Official Use Only Proprietary Information Because the Corroboration Study forms part of a license condition for the LAR, 1023 it cannot be changed without NRC approval. 1024 Moreover, it includes a specific provision to notify the NRC each time a corroboration action is completed. 1025

1. C-10s Prima Facie Case Dr. Saouma testified that the change in elastic modulus cannot reliably determine what has been the past through-thickness expansion in Seabrooks concrete. 1026 Moreover, he stated that each step of the Corroboration Study carries substantial uncertainties[.] 1027 As an example, he claimed that there are numerous uncertainties associated with NextEras use of the compressive strength measurement from Seabrooks construction to estimate elastic modulus 28 days from casting. 1028 Dr. Saouma testified that a major problem with the procedure by which NextEra calculated the normalized elastic modulus from the 28-day compressive strength is that concrete compressive strength increases over time (due to the hydration of the cement), with most of the increase occurring [in] the first few years. 1029 Dr. Saouma stated that failure to account for this increase would cause NextEra to underestimate the through-thickness expansion. 1030 To support this claim, C-10 introduced a textbook source that showed the 1023 Ex. NRC001-R, Staff Testimony at 43; Ex. INT024, Final SE at PDF 68-69; see Ex.

NER001, MPR Testimony at 61-62.

1024 Ex. NRC001-R, Staff Testimony at 29.

1025 Ex. INT024, Final SE at PDF 68; Ex. NER001, MPR Testimony at 62-63.

1026 Tr. at 771 (Saouma).

1027 Ex. INT030-R, Dr. Saouma Supp. Rebuttal Testimony at 1-4; see Ex. INT028, Dr. Saouma Rebuttal Testimony at 36-41 (non-public); Ex. INT032, Dr. Saouma Rebuttal Testimony at 36-41.

1028 Tr. at 514-15 (Saouma).

1029 Ex. INT030-R, Dr. Saouma Supp. Rebuttal Testimony at 1.

1030 Id.

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Official Use Only Proprietary Information compressive strength of a specified concrete sample is 20% higher after five years than the reference value measured at 28 days. 1031 Dr. Saouma further testified that another source of uncertainty in the NextEra study is the correlation between the normalized elastic modulus and through-thickness expansion, which is based on few test data at the [LSTP] and . . . have an inherent variability. 1032 Dr. Saouma also disagreed with NextEras use of the B Electrical Tunnel as the appropriate reference location for comparing Seabrooks concrete to the specimens used in the LSTP. C-10 noted there is a substantial difference between the measured 28-day compressive strengths at that tunnel versus the CEB and that this renders the LSTP tests not representative of the most critical part of the Seabrook reactor. 1033 Finally, Dr. Saouma stated that since there are so many uncertainties in the Corroboration Study, the figures containing the data and curves should contain error bars[.] 1034

2. NextEra and Staff Responses NextEra witnesses asserted that it compared data from the literature to data from the LSTP and confirmed that the trends are comparable and provide reasonable assurance that the modulus correlation can be applied at Seabrook. 1035 NextEra witnesses not only agreed with C-10 that the compressive strength increases with time just after the concrete is cast, but also agreed that it is a well-known phenomenon 1031 Id. at 1, 2 fig.1; Ex. NRC073, David Darwin, Charles W. Dolan, and Arthur H. Nilson, Design of Concrete Structures (McGraw Hill, Inc., 15th Ed. 2016) at 38 fig.2.5 [hereinafter Ex.

NRC073, Darwin, et. al.] (non-public); Tr. at 747-50 (Saouma).

1032 Ex. INT028, Dr. Saouma Rebuttal Testimony at 36-41 (non-public); Ex. INT032, Dr.

Saouma Rebuttal Testimony at 36-41; Ex. INT030-R, Dr. Saouma Supp. Rebuttal Testimony at 1-4.

1033 Tr. at 1144-46 (Saouma).

1034 Tr. at 1146 (Saouma).

1035 Ex. NER001, MPR Testimony at 118-20.

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Official Use Only Proprietary Information discussed in many textbooks. 1036 Additionally, NextEra witnesses agreed with Dr. Saouma that the increase is rapid early on, but that later it decreases rapidly to the point where it effectively plateaus [with] no difference in [aging] at that point. 1037 NextEra witness Dr. Bayrak conceded that compressive strength increases approximately 15-20% after the first twenty-eight days. 1038 However, Dr. Bayrak testified that over time, in terms of actual behavior, not calculations, the elastic modulus matures much earlier than [does] compressive strength[.] 1039 Dr. Bayrak stated that since NextEra did not measure the elastic modulus at the time of construction, it had to use the compressive strength measurements available at that time. 1040 NextEra witnesses stated that the evidence clearly establishes that NextEra adequately addressed any uncertainty in the elastic modulus correlation. 1041 As for C-10s assertion that the compressive strength initially increases due to the hydration of the cement, with most of the increase occurring the first few years, NextEra witnesses stated that the modulus correlation inherently accounts for that effect. 1042 NextEra witnesses further stated that since the test data it used to determine the correlation were from concrete that had cured to the point that the increase in compressive strength either had already been realized for the great majority of the data or, in the case of three data sets, was insignificantly different from being fully realized. 1043 1036 Ex. NER076, Testimony of NextEra Witnesses John Simons, Christopher Bagley, Oguzhan Bayrak, and Edward Carley in Response to Exhibit INT030 at 6 [hereinafter Ex. NER076, NextEra Response to Ex. INT030-R] (non-public).

1037 Tr. at 749-50 (Bagley); Ex. NER076, NextEra Response to Ex. INT030-R at 6-7 (non-public).

1038 Tr. at 752-53 (Bayrak).

1039 Tr. at 753 (Bayrak).

1040 Tr. at 756 (Bagley).

1041 Ex. NER076, NextEra Response to Ex. INT030-R at 4 (non-public); Ex. INT018-R, MPR-4153, Rev. 3 § 4.2; Ex. INT020, MPR-4153, Rev. 3 § 4.2 (non-public).

1042 Ex. NER076, NextEra Response to Ex. INT030-R at 2 (non-public).

1043 Id. at 2, 8 (non-public).

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Official Use Only Proprietary Information Thus, NextEra maintained that no adjustments to the modulus correlation were necessary to account for differences in hydration of the cement as a function of time. 1044 NextEra witness Mr. Carley testified that NextEra currently has forty-eight extensometers installed and the Corroboration Study would pull cores from 20%, i.e. approximately ten of those locations. 1045 More specifically, in order to increase the conservatism in the methodology, NextEra plans to examine the data from those forty-eight extensometers and choose the 20%

showing the highest level of expansion, which should show the greatest agreement with the correlation curve. 1046 Moreover, NextEra will introduce a reduction factor of to the normalized elastic modulus to increase the calculated degradation, or through-thickness expansion. 1047 In addition, NextEra witness Mr. Bagley stated that NextEra would take a look at all the data points to see what makes the most sense for executing the Corroboration Study. 1048 NextEra witness Mr. Carley testified that if the Corroboration Study does not confirm consistency with the LSTP modulus correlation results, it will implement the Corrective Action Program. 1049 Although NextEra does not know currently what corrective actions it would take, it would proceed under NRC oversight. 1050 The Staff challenged several of Dr. Saoumas assertions regarding the modulus correlation together with the measured elastic modulus to determine the through-thickness expansion at Seabrook. For example, Dr. Saouma faulted a lack of error bars in displaying the 1044 Id. at 2 (non-public).

1045 Tr. at 1009 (Carley).

1046 Tr. at 1013-14 (Carley).

1047 Ex. NER076, NextEra Response to Ex. INT030-R at 4-5 (non-public); see Ex. INT018-R, MPR-4153, Rev. 3 § 4.2.2; Ex. INT020, MPR-4153, Rev. 3 § 4.2.2 (non-public).

1048 Tr. at 1015 (Bagley).

1049 Ex. INT024, Final SE at PDF 68; Tr. at 1009-10 (Carley).

1050 Tr. at 1010 (Carley, Lehman).

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Official Use Only Proprietary Information results of the modulus correlation and data. 1051 The Staff disagreed and stated that the correlation is used in the context of the design basis codes, which do not use error bars but incorporate normal variability into their equations. 1052 The Staff likewise disputed C-10s argument that the correlation fails to account for the increase in compressive strength of concrete over time, and thus would underestimate through-thickness expansion. In this regard, Dr. Saouma stated that the compressive strength after five years could be as much as 20% higher than the value measured at 28 days. 1053 According to the Staffs analysis, even if this were the case at Seabrook, NextEras reduction factor would bound this uncertainty. 1054

3. Findings of Fact and Board Analysis First, the Board notes that there has been some confusion as to what constitutes the Corroboration Study. According to NextEra, Dr. Saoumas Supplemental Rebuttal Testimony conflated the modulus correlation and the Corroboration Study, which NextEra stated are two different concepts. 1055 NextEra called attention to Dr. Saoumas alleged misunderstanding and expressly identified the differences between these two concepts. According to NextEra the modulus correlation is used to estimate the through-thickness expansion at Seabrook before an extensometer is installed[,] 1056 whereas [t]he [C]orroboration [S]tudy is an approach for 1051 Tr. at 797 (Saouma).

1052 Ex. NRC090, Staff Testimony in Response to Exhibit INT030 at 4 [hereinafter Ex. NRC090, Staff Testimony in Response to Ex. INT030-R] (Dr[.] Saouma mischaracterizes normal variability in the data underlying the code equation as a margin of error in the code equation.).

1053 Ex. INT030-R, Dr. Saouma Supp. Rebuttal Testimony at 1.

1054 Ex. NRC090, Staff Testimony in Response to Ex. INT030-R at 5-6.

1055 Ex. NER076, NextEra Response to Ex. INT030-R at 2 (non-public).

1056 Id.

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Official Use Only Proprietary Information obtaining in-plant data to evaluate how expansion at the plant aligns with observed expansion of the LSTP specimens. 1057 Because C-10s challenge pertains to NextEras method of estimating pre-extensometer through-thickness expansion, we interpret it as a challenge to the modulus correlation, not the Corroboration Study. 1058 The Board does not agree with NextEras assessment that Dr.

Saouma misunderstood the difference between the modulus correlation and the Corroboration Study. In fact, Dr. Saouma explicitly stated that [t]he [C]orroboration [S]tudy is used to evaluate how expansion at the plant aligns with observed expansion of the LSTP specimens. 1059 Further, Dr. Saouma also highlighted the following NextEra description of the study: the [C]orroboration [S]tudy focuses on a correlation developed during the LSTP that is used by NextEra to estimate through-thickness expansion at Seabrook before an extensometer is installed. 1060 Thus, we find that Dr. Saouma fully understood the difference between the modulus correlation and the Corroboration Study, and C-10 focused its comments on the modulus correlation as a critical element of the Corroboration Study.

NextEras proposed ASR expansion monitoring program was a first-of-a-kind approach, and as a result, the Staff imposed a license condition on the LAR that requires NextEra to confirm the continued applicability of the LSTP to ASR-affected structures at Seabrook. 1061 To ensure continued applicability, the Corroboration Study will cover at least 20%

of the extensometer locations on the worst ASR-affected structures. 1062 NextEra will complete 1057 Ex. NER001, MPR Testimony at 62.

1058 See Ex. INT030-R, Dr. Saouma Supp. Rebuttal Testimony at 1-4.

1059 Id. at 1 (quoting Ex. NER001, MPR Testimony at 62).

1060 Ex. INT032, Dr. Saouma Rebuttal Testimony at 36 (quoting Ex. NER001, MPR Testimony at 62).

1061 Ex. INT024, Final SE at PDF 40, 67-69; Ex. NER001, MPR Testimony at 61-62.

1062 See Tr. at 1009, 1013-14 (Carley).

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Official Use Only Proprietary Information the initial study no later than 2025 and a follow-up study ten years thereafter. 1063 If there is any indication that the LSTP results do not continue to apply to Seabrook structures, then NextEra will be required to conduct, under NRC oversight, prompt operability determinations, and if needed, pursue corrective actions, including facility shutdown. 1064 Dr. Saouma stated that there are so many uncertainties involved in the modulus correlation as implemented that it puts the entire Corroboration Study in jeopardy. 1065 One of C-10s biggest challenges concerns what it perceived to be NextEras failure to take into account early cement hydration, which causes the compressive strength to increase just after casting and continue for some time afterward. 1066 If true, this could invalidate NextEras approach.

However, NextEra witnesses testified that NextEra properly accounted for this effect in its analysis. 1067 Also, both Staff and NextEra witnesses testified that the normalized elastic modulus reduction factor allows sufficient conservatism in the analysis to account for this effect. 1068 After careful consideration of the parties arguments, the Board finds C-10s arguments unpersuasive. The Corroboration Study is a critical part of the LAR, because it allows NextEra periodically to ascertain whether the results of the LSTP remain relevant for the continued 1063 Ex. INT024, Final SE at PDF 68-69.

1064 Id. at PDF 68; Tr. at 719-20 (Buford, Lehman), 739-42 (Buford, Simons), 1012-13 (Buford, Bagley).

1065 Ex. INT028, Dr. Saouma Rebuttal Testimony at 36-41 (non-public); Ex. INT032, Dr.

Saouma Rebuttal Testimony at 36-41; Ex. INT030-R, Dr. Saouma Supp. Rebuttal Testimony at 1-4.

1066 Ex. INT030-R, Dr. Saouma Supp. Rebuttal Testimony at 1.

1067 Ex. NER076, NextEra Response to Ex. INT030-R at 2 (non-public).

1068 Ex. NER001, MPR Testimony at 120; Ex. NER003, MPR Testimony, Proprietary Appendix at 9 fig.10 (non-public); Ex. INT018-R, MPR-4153, Rev. 3 § 4.2.2; Ex. INT020, MPR-4153, Rev.

3 § 4.2.2 (non-public); Ex. NRC090, Staff Testimony in Response to Ex. INT030-R at 5-6.

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Official Use Only Proprietary Information monitoring of Seabrook seismic Category I structures. 1069 Therefore, the Board agrees with NextEra and the Staff, and based upon a preponderance of the evidence, it finds that NextEras approach to the Corroboration Study, including the modulus correlation, provides reasonable assurance of adequate protection.

E. Concrete Delamination and Localized Excursions Outside the Linear Elastic Regime Delamination occurs when laminate or solid structures split or separate. 1070 This gradual separation creates internal cracks in the structure, or in Seabrooks case, the concrete. 1071 Both cracks that are hidden below the surface and cracks that manifest on the surface could indicate hazardous delamination. 1072 During the process of delamination, microcracks become macrocracks that tend to run parallel to the direction of the restraint. 1073 Microcracks reduce the mechanical and material properties of ASR-affected concrete (compressive strength, elastic modulus, tensile strength, shear strength, and flexural strength) and may reduce its structural capacity. 1074 Delamination takes the form of mid-plane cracks. 1075 Generally, ASR expansion occurs in three orthogonal directions. 1076 When there is a confinement of the concrete in two orthogonal directions, the 1069 Ex. INT024, Final SE at PDF 67-69.

1070 See Ex. INT027, Dr. Saouma Pre-Filed Testimony at 17 fig. 10.

1071 Tr. at 556-57 (Saouma).

1072 Tr. at 1141 (Saouma).

1073 Ex. NER012, ISE Structural Effects of [ASR] at 13 (non-public); Tr. at 770, 890-91 (Saouma).

1074 Ex. NRC001-R, Staff Testimony at 7; see Tr. at 573-74 (Saouma).

1075 Tr. at 770 (Saouma).

1076 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 6 (If unimpeded, ASR expansion is volumetric and isotropic (i.e., the same amount of expansion occurs in three directions or planes).); see Ex. NER001, MPR Testimony at 121; Ex. NER004, SGH Testimony at 66.

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Official Use Only Proprietary Information ASR expansion will plateau in those directions and then reorient along the unconfined direction. 1077 This process instigates the delamination.

If delamination poses a problem for the operation of Seabrook, then the problem could be exacerbated if Seabrooks operational parameters experience localized excursions outside the linear elastic regime, 1078 which is one of Dr. Saoumas concerns. 1079 According to the ASME and ACI 318-71 design codes, the responses to stresses on the structural components at Seabrook are generally assumed to be elastic. 1080 However, during their testimony both NextEra and the Staff stated that this may not always be the case for localized regions of Seabrook. 1081 Therefore, excursions of Seabrook outside the linear elastic regime deserve careful attention.

1. Motion in Limine NextEra moved to exclude C-10s testimony concerning the longitudinal crack exhibited in the LSTP. Specifically, NextEra moved to exclude Dr. Saoumas pre-filed testimony section C.2.3.2 and Dr. Saoumas rebuttal testimony sections D7.1 and D7.2 as these challenges relate[] to the execution of the LSTP that could have been, but were not, raised at the outset of 1077 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 6.

1078 Linear elastic regime, or linear elastic behavior, refers to conditions under which a structure returns to its original configuration when loads are removed. See Ex. NER004, SGH Testimony at 52.

1079 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 7, 32; Ex. INT032, Dr. Saouma Rebuttal Testimony at 43; Tr. at 869-70, 1056 (Saouma).

1080 Tr. at 303 (Bell), 869 (Thomas); Ex. NER001, MPR Testimony at 133-34; Ex. NER004, SGH Testimony at 52-56; Ex. INT024, Final SE at PDF 57.

1081 Tr. at 728-29 (Bolourchi), 868-69 (Bell), 869 (Thomas), 1085 (Thomas), 1091-93 (Thomas); Tr. at 864-65 (Bell) (With respect to the ACI [318-71] code, the requirements are a little bit different. You are allowed some amount of plasticity in areas of high stress . . . So again, the codes of record limit how much plasticity there can be in the ACI code. The ASME code allows none.).

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Official Use Only Proprietary Information this proceeding. 1082 C-10 opposed the motion. 1083 We find that Dr. Saoumas arguments regarding the longitudinal crack in the LSTP are fairly encompassed by the description of the admissible contentions as he questions the representativeness of the LSTP. 1084 In this respect, NextEras Motion in Limine is denied.

Dr. Saouma initially noted that the longitudinal crack jeopardizes the representativeness of the ensuing test. 1085 Dr. Saouma likened the longitudinal crack to a delamination crack and

[t]herefore, the specimen that was tested cannot be considered representative as it was already damaged, and ensuing results would be unreliable. 1086 However, in Dr. Saoumas rebuttal testimony, he stated that the alleged delamination crack is in fact representative of Seabrook. 1087 Indeed, Dr. Saouma testified that the longitudinal crack may have impacted the validity of the shear tests[,] and, despite the alleged unreliability of the shear tests, such a

[delamination] crack . . . may form inside the walls of Seabrook. 1088 Further, Dr. Saouma stated that there is the perfect storm of variables at Seabrook for delamination to occur. 1089 Without addressing the seemingly contradictory arguments in Dr. Saoumas pre-filed and rebuttal testimonies, we decline to exclude such testimony as it is envelope[d] within the bases 1082 NextEra MIL 2 at 17-18 (emphasis omitted). NextEra also moved to exclude Dr. Saoumas pre-filed testimony section C.2.3.1 (Load Displacement), however he withdrew that argument during the hearing. Id.; Tr. at 314 (Saouma); Ex. INT001-R, Dr. Saouma Pre-Filed Testimony § C.2.3.1 (non-public); Ex. INT027, Dr. Saouma Pre-Filed Testimony § C.2.3.1.

1083 C-10 Opp. to MIL 2 at 20.

1084 Pilgrim, CLI-10-11, 71 NRC at 310.

1085 Ex. INT001-R, Dr. Saouma Pre-Filed Testimony at 16 (non-public); Ex. INT027, Dr. Saouma Pre-Filed Testimony at 16.

1086 Ex. INT001-R, Dr. Saouma Pre-Filed Testimony at 16 (non-public); Ex. INT027, Dr. Saouma Pre-Filed Testimony at 16.

1087 Ex. INT028, Dr. Saouma Rebuttal Testimony at 26-33 (non-public); Ex. INT032, Dr.

Saouma Rebuttal Testimony at 26-33.

1088 Ex. INT028, Dr. Saouma Rebuttal Testimony at 29 (non-public); Ex. INT032, Dr. Saouma Rebuttal Testimony at 29.

1089 Ex. INT032, Dr. Saouma Rebuttal Testimony at 30.

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Official Use Only Proprietary Information of the reformulated contention and directly related to the representativeness of the LSTP. 1090 As noted, but not repeated here, 1091 we decline to apply NextEras narrow approach to defining the bases of the reformulated contention. Here, there is a plain connection between the presence of the longitudinal crack and representativeness. If, in fact, the longitudinal crack affected the results of the LSTP, the Board should consider such testimony. If the longitudinal crack rendered the LSTP data unreliable that would undoubtedly implicate representativeness.

In addition, the presence of the longitudinal crack is closely related to the issue raised by admitted Contention C, one of the bases of the reformulated contention. In Contention C, C-10 maintained that [t]horough petrographic analysis, including core sample testing of Seabrooks in-situ concrete, must be integral to NextEras assessment of the advance of ASR. 1092 C-10 argued in support of Contention C that petrographic analysis was needed to detect microcracking and that [u]ntil thorough petrographic analysis is performed on Seabrooks concrete structures, NextEra has no real basis by which it can reassure . . . the NRC[ ] that Seabrooks ASR progression is truly understood. 1093 As explained below, Dr. Saouma testified that NextEra should perform petrographic analysis of concrete cores from Seabrook structures to detect microcracks, which eventually coalesce into larger cracks that may lead to delamination. That testimony falls within the scope of Contention C. Dr. Saoumas pre-filed and rebuttal testimony concerning the longitudinal crack in the LSTP also emphasized the risk of 1090 See Catawba, LBP-04-12, 59 NRC at 391.

1091 See supra Part VIII.A.2.a.

1092 LBP-17-7, 86 NRC at 107 (quoting C-10 Petition at 6).

1093 Id. at 108 (quoting C-10 Petition at 8).

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Official Use Only Proprietary Information delamination at Seabrook, 1094 and therefore further supports Contention Cs demand for thorough petrographic analysis of Seabrook concrete cores.

We now address the persuasiveness of C-10s arguments concerning delamination.

2. C-10s Prima Facie Case Dr. Saouma stated that changes in humidity and temperature may produce gradients within the Seabrook walls, and when coupled with Seabrooks rebar being located close to the surface, cracking on the surface of its walls will not be representative of cracking in the interior. 1095 Dr. Saouma testified that such delamination is unlikely to be captured by an extensometer because of the patchy nature of ASR hot-spots or pockets, and because there may not be corresponding surface in-plane cracks that can be detected by the CI method. 1096 Since ASR is not homogeneous within the walls[,] . . . failure to capture that internal [micro and macro]crack[s] with extensometers[] does not mean that crack[s are not present] inside the wall. 1097 Dr. Saouma testified that the development of microcrack[s] as a result of ASR cannot be neglected. 1098 According to Dr. Saouma, NextEras failure to detect microcracks without seeing surface damage is because they are indeed micro-sized cracks, 1099 where the descriptor micro means that they are too small to be observed with the naked eye. 1100 1094 Ex. INT001-R, Dr. Saouma Pre-Filed Testimony at 15-17 (non-public); Ex. INT027, Dr.

Saouma Pre-Filed Testimony at 15-17; Ex. INT028, Dr. Saouma Rebuttal Testimony at 26-33 (non-public); Ex. INT032, Dr. Saouma Rebuttal Testimony at 26-33.

1095 Tr. at 836-37 (Saouma); Ex. INT032, Dr. Saouma Rebuttal Testimony at 28, 31.

1096 Ex. INT032, Dr. Saouma Rebuttal Testimony at 31.

1097 Id.; see Tr. at 696 (Saouma).

1098 Tr. at 1087 (Saouma); see Ex. NRC075, Deschenes, et al. at 12.

1099 Tr. at 1086 (Saouma).

1100 Tr. at 1140 (Saouma).

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Official Use Only Proprietary Information Dr. Saouma, quoting the literature, testified that the behavior of concrete at high stresses and [at] fracture is influenced by microcracking and other discontinuit[ies]. 1101 Dr.

Saouma further testified that [t]he moment the concrete stress exceeds 0.45 [compressive strength], and never mind about ASR, there are microcracks, and we enter the non-linear regime. On top of that, even if you are below [0].45 [compressive strength], you have the non-linearity induced by the microcracking due to ASR. 1102 Dr. Saouma suggested the possibility that the so-called edge effect cracks in the LSTP were symptomatic of delamination. 1103 In the case of delamination, the concrete wants to expand, but it is confined in two directions, with the only free direction being the through-thickness direction. 1104 The process starts as internal microcracking that coalesces into larger cracks. 1105 Over time, roughly seven years, complete delamination may occur. 1106 Dr. Saouma further testified that similar cracking could occur in the concrete at Seabrook, avoiding detection by NextEra under the current monitoring scheme. 1107 In support, Dr. Saouma provided the example of the delamination crack between two reinforcing mats that occurred at the Crystal River nuclear containment. 1108 Although not 1101 Tr. at 1102 (Saouma); see Ex. NRC073, Darwin, et. al. at 45 (non-public).

1102 Tr. at 1093-94 (Saouma).

1103 Ex. INT028, Dr. Saouma Rebuttal Testimony at 26-33 (non-public); Ex. INT032, Dr.

Saouma Rebuttal Testimony at 26-33.

1104 Tr. at 1140-41 (Saouma).

1105 Tr. at 534 (Saouma), 891 (Saouma), 1108-09 (Saouma); Ex. NER012, ISE Structural Effects of [ASR] at 13 (non-public); see Ex. NRC001-R, Staff Testimony at 12.

1106 Tr. at 1140-41 (Saouma).

1107 Tr. at 572, 1161-63 (Saouma); see Ex. INT028, Dr. Saouma Rebuttal Testimony at 26-33 (non-public); Ex. INT032, Dr. Saouma Rebuttal Testimony at 26-33.

1108 Ex. INT001-R, Dr. Saouma Pre-Filed Testimony at 16-17, 17 fig.10 (non-public); Ex.

INT027, Dr. Saouma Pre-Filed Testimony at 16-17, 17 fig.10.

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Official Use Only Proprietary Information caused by ASR degradation, it points to the existence of delamination as a real-life phenomenon. 1109 Dr. Saouma testified that petrography is one of the methods that NextEra could utilize to detect the existence of microcracking with its potential for delamination beneath the surface. 1110 As another method, Dr. Saouma stated that one could [p]ut the specimen under direct tension to find out if the resulting tensile strength[] is below what is perceived to be the tensile strength.

That would reflect the microcracking, which is inside. 1111 Dr. Saouma questioned the lack of conservatism caused by inputting the same thermal expansion in all three directions into NextEras FEA, thereby ignoring the fact that most of the expansion is in the through-thickness direction. According to Dr. Saouma, NextEra should have used an anisotropic (i.e., not the same in every direction) coefficient of thermal expansion. 1112 Even though NextEra stated that it used a relative value that it measured in each direction for its inputs, 1113 Dr. Saouma challenged this assertion. He stated that he could not find anywhere in the exhibits an indication that an anisotropic coefficient of thermal expansion for all three directions was used. 1114 Dr. Saouma further asserted that localized excursions outside the linear elastic regime at Seabrook Unit 1 would be especially dangerous if delamination should occur and stated [i]t only takes this one localized failure to trigger a massive damage. Im not talking about a total 1109 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 16 (Th[e longitudinal crack] is not unlike the delamination crack (between reinforcement mats) that occurred at Crystal River (though for entirely different cause)[.]).

1110 Tr. at 1140 (Saouma).

1111 Tr. at 573 (Saouma).

1112 Tr. at 351 (Saouma); Ex. INT027, Dr. Saouma Pre-Filed Testimony at 26; Ex. INT032, Dr.

Saouma Rebuttal Testimony at 33, 41.

1113 Tr. at 351, 1171-74 (Bolourchi); see Ex. INT015, SGH Evaluation and Design Confirmation of As-Deformed CEB at 93 tbl.13.

1114 Tr. at 351, 1172 (Saouma).

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Official Use Only Proprietary Information collapse. One localized point. Going into plastification which is not accounted for, thats it.

[K]aput. 1115 Dr. Saouma also stated [w]e need to define failure, because failure does not mean the collapse of the whole structure. We have localized failure. This is what is of concern. Its the localized failure which is going to lead to an unacceptable leakage. 1116 To further complicate the issue of the possibility of localized failures, Dr. Saouma testified that the failure mode associated with combined ASR degradation and an earthquake is a shear failure, which is entirely different from steel yielding, which is the traditional flexure failure mode of a section under ultimate load. 1117 The latter gives plenty of warning, while shear failure is brittle with no indication that failure is about to occur. 1118 Considering the above arguments, the Board finds that C-10 has provided sufficient expert testimony to satisfy its burden of going forward.

3. NextEra and Staff Responses According to NextEra witnesses, [e]xpansion reorientation in the through-thickness direction does not occur until sufficient in-plane expansion has produced chemical prestressing with the reinforcing bars. Therefore, [NextEra concluded that] cracking in the through-thickness direction would not occur without any symptoms of expansion in the in-plane directions. 1119 This conclusion is based in part on NextEras observations in the LSTP. In that program, the specimens contained bi-directional reinforcement in the in-plane directions similar to Seabrook, and during the expansion monitoring, initially, expansion occurred at approximately the same 1115 Tr. at 869-70 (Saouma). Plastification is a state in which a structure does not return to its original configuration when loads are removed.

1116 Tr. at 821 (Saouma).

1117 Tr. at 1058 (Saouma).

1118 Id.

1119 Ex. NER001, MPR Testimony at 164.

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Official Use Only Proprietary Information rate in all directions until the in-plane expansion reached a certain level, after which the expansion reoriented to occur primarily in the unreinforced through-thickness direction. 1120 For the LSTP, NextEra witnesses testified that ASR progression in the test specimens was monitored in several different ways and in many different locations. 1121 It performed crack width summation on both sides of [a] test specimen, which provided in-plane expansion at the surface in two separate locations. 1122 NextEra witnesses stated that NextEra monitored through-thickness expansion by through-specimen embedded rods on both sides of each specimen. While the results showed variability that is within the expected range for concrete, there were no indications of significant non-homogeneity within any test specimen. 1123 Insofar as LSTP specimens displayed structural cracks on the side faces 1124 both NextEra and the Staff attributed this to an edge effect, since the cracking only extended down a couple of inches to about where the rebar started. 1125 NextEra witnesses testified that there was no delamination observed in the LSTP. 1126 NextEra witnesses testified that it never found a spot at Seabrook where the extracted concrete cores indicated worse cracking at depth within the cores beyond what was indicated at the surface. 1127 Moreover, NextEra witnesses testified that in previous studies of 200 cores taken from Seabrook, it found no substantial difference between near-surface cracking and 1120 Id. at 91 (citing Ex. NER003, MPR Testimony, Proprietary Appendix at 5 fig.4 (non-public)).

1121 Id. at 94.

1122 Id.

1123 Id.

1124 Tr. at 358 (Saouma), 360 (Bayrak).

1125 Tr. at 565-69 (Bayrak), 1138-39 (Buford).

1126 Tr. at 704 (Bayrak), 1139 (Thomas).

1127 Tr. at 397 (Sherman), 556 (Bayrak), 572 (Carley), 700 (Sherman).

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Official Use Only Proprietary Information cracking below the level of the reinforcing steel within the core of the structure, 1128 as confirmed by both visual and petrographic examinations. 1129 NextEra witnesses stated that finite element codes do not provide direct inputs for ASR expansion, but that thermal expansion can be used as a proxy, and therefore ASR strain is simulated by applying an equivalent thermal load to the concrete. 1130 Thus, NextEra witness Mr.

Bell asserted that FEAs allow for consideration of self-straining forces like ASR with inputs for thermal load with expansion coefficients. 1131 According to NextEra:

The ASR load inputs to these models are: (1) the internal in-plane ASR expansion of reinforced structural members, and (2) the pressure due to ASR expansion of the concrete fill. The internal ASR expansion is determined via the field-measured CI expansion strain; CI is measured in each of the in-plane orthogonal directions. CI represents an equivalent ASR strain. 1132 The EPRI Report states that restrained expansion in one or more directions affects the development of ASR and results in anisotropic damage. 1133 According to Staff witness Ms. Buford, the Staff has not seen, in either the literature or the [LSTP], any evidence of there being no indications of ASR in the planar directions visible, and then significant ASR occurring through the thickness of the concrete. 1134 Ms. Buford further stated [w]ith that preponderance of the evidence, we have reasonable assurance that there is not extensive damage happening that is not visiblethat wouldnt be visible by either in-1128 Tr. at 455-56 (Sherman), 560 (Buford), 572 (Carley), 705 (Bayrak); 1097-98 (Bayrak).

1129 Tr. at 455-56 (Sherman), 531-32 (Carley); Ex. NER001, MPR Testimony at 93.

1130 Ex. NER004, SGH Testimony at 40, 66.

1131 See Tr. at 861 (Bell).

1132 Ex. NER004, SGH Testimony at 40.

1133 Ex. NER017, EPRI Report at 4-1 (non-public).

1134 Tr. at 1133 (Buford).

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Official Use Only Proprietary Information plane cracking or some sort of deformation, which is being monitored and managed in a separate program. 1135 As for localized excursions outside the linear elastic regime at Seabrook Unit 1, both NextEra and Staff witnesses testified that this may indeed occur due to extreme loads, such as seismic loads. 1136 Moreover, Staff witness Dr. Thomas stated that such excursions are typical for the roughly 100 reactors operating around the country. 1137 The Staff also recognized, however, that ACI 318-71 addresses this issue by using a methodology called equivalent linear analysis. 1138 Also, NextEra witness Dr. Bolourchi testified, and the Staff agreed, 1139 that as for the containment at Seabrook Unit 1, which is designed according to ASME Section III, Division 2, [t]he only situation where a containment goes beyond [the] elastic limit is under the accident temperature. The load combination involving the accident pressure by itself is within [the]

elastic limit. 1140 For certain structures governed by the ACI 318-71 code, except for the CEB, some controlled excursions into the nonlinear plasticity regime in areas of high stress are allowed. 1141 The codes of record limit how much plasticity is permitted in the ACI code, while the ASME code allows none. 1142 Staff witness Dr. Thomas stated that localized nonlinear excursions are manageable, because the design code ensures that if [a Seabrook structure is] pushed to failure you get a 1135 Tr. at 1133-34 (Buford).

1136 Tr. at 729 (Bolourchi), 869 (Thomas), 1085 (Thomas), 1091 (Thomas).

1137 Tr. at 1055-56 (Thomas).

1138 Tr. at 728-29 (Bolourchi), 1055 (Thomas).

1139 Tr. at 869 (Thomas).

1140 Tr. at 729 (Bolourchi).

1141 Tr. at 728-29 (Bolourchi), 864-65 (Bell), 868-69 (Bell).

1142 Tr. at 864-65 (Bell).

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Official Use Only Proprietary Information ductile failure, which means your steel should yield first rather than concrete failing in compression. 1143 According to NextEra, if any limits in the ASR expansion monitoring program are approached, it then will perform reanalysis or remediation, as necessary. 1144 Staff witnesses stated that if Seabrook ever approached or exceeded the limits of its codes of record, NextEra would have to perform prompt operability determinations and come into compliance with its licensing basis or seek approval for a license amendment. 1145 For the prompt operability determination, NextEra would be obligated to demonstrate that the structures were operable, even if degraded. 1146

4. Findings of Fact and Board Analysis A contentious issue at the hearing concerned whether cracking of the concrete at Seabrook Unit 1 could be worse internally than it appears on the surface. If more serious internal cracking were the case, an unforeseen delamination of the concrete could result in structural failure. Thus, the concern is that internal microcracking and delamination could be degrading Seabrooks concrete, unnoticed by the current SMP monitoring protocol.

The FHWA Report states concrete expansion [due to ASR] can also result in steel yielding, loss of concrete/steel bond, concrete delamination, with potential weakening of the structural integrity of the concrete member or structure. 1147 Thus, the FHWA Report acknowledges the potential for ASR-degradation leading to concrete delamination. The report further explains that the structural assessment of an ASR-affected structure must focus on a 1143 Tr. at 1057 (Thomas).

1144 Tr. at 392 (Collins).

1145 See Tr. at 719-20 (Buford, Lehman), 739-42 (Buford), 1012 (Buford).

1146 Tr. at 948-49 (Buford).

1147 See Ex. NER013, FHWA Report at 35.

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Official Use Only Proprietary Information number of aspects, including concrete delamination. 1148 Then, [t]he decision should be made concerning the application of appropriate remedial measures . . . . 1149 The ISE document also states that where there is no [through-thickness] reinforcement there is now more evidence of delamination . . . developing with Severe [ASR]. 1150 The Board must determine, based upon the preponderance of the evidence, whether NextEra has established its position that the possibility of delamination of the concrete at Seabrook is sufficiently understood and monitored such that the continued operation of Seabrook will not endanger[] the health and safety of the public. 1151 The Board notes that C-10 initially argued that the edge effect crack observed in LSTP specimens was indicative of delamination and thus rendered the LSTP test specimens unreliable and not representative of conditions at Seabrook. 1152 Subsequently, C-10 stated that delamination may indeed occur at Seabrook, and thus the LSTP mid-plane crack is representative. 1153 The majority of C-10s arguments concerned the possibility of delamination at Seabrook. Thus, the Board assesses C-10s testimony according to the latter view.

As part of its SMP monitoring protocol, NextEra removes concrete cores from Seabrook at the locations where it has installed extensometers. 1154 The cores and corresponding boreholes are then subjected to visual examination to confirm the absence of mid-plane 1148 Id.

1149 Id.

1150 See Ex. NER012, ISE Structural Effects of [ASR] Addendum at 3 of 5 (non-public).

1151 10 C.F.R. § 50.57(a)(3).

1152 Ex. INT001-R, Dr. Saouma Pre-Filed Testimony at 15-17 (non-public); Ex. INT027, Dr.

Saouma Pre-Filed Testimony at 15-17; C-10 Opp. to MIL 2 at 14.

1153 Ex. INT028, Dr. Saouma Rebuttal Testimony at 28-29 (non-public); Ex INT032, Dr. Saouma Rebuttal Testimony at 28-29; Tr. at 707 (Saouma).

1154 Ex. NER007, Seabrook [SMP] Manual Rev. 7 at 3-1.5 (non-public).

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Official Use Only Proprietary Information cracks. 1155 Thus, NextEra conceded that it is concerned about the potential for mid-plane cracking that could possibly lead to delamination. 1156 However, an LSTP conclusion that guides the SMP is that there is no internal ASR-induced cracking that is worse than cracking that is visible on the surface. 1157 The Staff concurred with this view and stated [e]xpansion 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]. 1158 NextEra used the CI measurements at Seabrook to implement thermal loads in its FEA. 1159 Since the measured CI values in the horizontal and vertical directions were different, anisotropy was implemented for those directions; 1160 however, NextEra did not implement such a procedure for the through-thickness direction, arguing that their use of shell elements in the FEA rendered it unnecessary. 1161 Given the uncertainties in NextEras approach and the potential severitycatastrophic failureof a delamination event, NextEra has not persuaded us that it is properly accounting for the possibility of delamination. Indeed, given the example of the unforeseen delamination and subsequent significant structural damage at the Crystal River nuclear plant, 1162 albeit for non-ASR reasons, delamination is an issue that cannot be ignored.

NextEra and Staff statements that they have not seen delamination in any of the 200 core 1155 Id. (non-public); Ex. NER020, MPR 0326-0062-88, Rev. 2 at 4 (non-public); Tr. at 455-56 (Sherman), 572 (Carley), 704-05 (Bayrak), 710-11 (Carley), 1096-98 (Bayrak).

1156 Tr. at 710-11 (Carley), 1097-98 (Bayrak).

1157 Tr. at 358 (Bayrak).

1158 Ex. NRC001-R, Staff Testimony at 64.

1159 Ex. NER004, SGH Testimony at 40-41, 66; see Ex. INT022, SEM at PDF 18-24.

1160 Ex. INT015, SGH Evaluation and Design Confirmation of As-Deformed CEB at 93 tbl.13 (showing the separate hoop (i.e., horizontal) and meridional (i.e., vertical) CI measurements used in the FEA).

1161 Ex. NER004, SGH Testimony at 63-64, 66; Tr. at 954, 1174 (Bolourchi).

1162 Ex. INT001-R, Dr. Saouma Pre-Filed Testimony at 16-17 (non-public); Ex. INT027, Dr.

Saouma Pre-Filed Testimony at 16-17.

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Official Use Only Proprietary Information samples that they have examined fall short when compared to the potential severity of not catching an unseen problem. Indeed, microcracking cannot be seen with the naked eye, but must be observed by another method, such as petrography, 1163 and NextEra testified that it did not perform petrographic examinations on all the cores that it extracted from Seabrook. 1164 In other words, since the SMP is based upon the paradigm that internal cracking is first evidenced by surface cracking as measured by various cracking indices, 1165 any phenomenon without surface cracking will escape detection. The Board finds that NextEra does not have an adequate screening procedure to detect internal cracking and delamination in Seabrooks concrete.

The further complicating issue of localized excursions of Seabrook structures outside the linear elastic regime is a serious concern. Since the failure mode associated with combined ASR degradation and an earthquake is a brittle, shear failure without ample warning of its occurrence, 1166 the Board is concerned about the potential for sudden significant, localized damage due to shear failure, given that all parties agreed that there may be localized excursions of Seabrook Unit 1 into the nonlinear structure plastification regime. The Staff is confident that it can handle oversight of NextEras response to such behavior, given its experience with applying the design code to localized nonlinearities at the other approximately 100 nuclear reactors in operation across the United States. 1167 However, those excursions at the other reactors do not involve the newly found phenomenon of reactor concrete degradation due to ASR.

1163 Tr. at 1140 (Saouma).

1164 Tr. at 532 (Carley) ([I]n some cases, we do . . . petrographic examination. We have done it.

We just dont do it on every single core.).

1165 Ex. INT010, Original LAR at PDF 32 tbl.4; see supra Part VIII.A.2.

1166 Tr. at 1058-59 (Saouma).

1167 Tr. at 1055-56 (Thomas).

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Official Use Only Proprietary Information The Board notes the lack of experience in the other reactors around the country in addressing the possibility of ASR-induced localized excursions outside the linear elastic regime.

The Board also is not persuaded that NextEra and the Staff have a sound plan in place to detect and address internal microcracking and the potential for an unforeseen delamination. Thus, the Board finds that NextEra has not shown, by a preponderance of the evidence, that there is reasonable assurance that the continued operation of Seabrook Unit 1 will not endanger the health and safety of the public with regard to this particular issue of delamination. However, these shortcomings of the LAR can be corrected. According to a Report of the Swiss Committee on Dams, [ASR] generated micro-cracks and associated gel precipitations are easily recognizable under the light microscope during the petrographic analysis of a core.

Thus, the Board finds that the petrographic analysis of each extracted core would gauge the degree of internal microcracking (possibly resulting in macrocracking) that could lead to catastrophic delamination.

Therefore, the Board imposes the following license condition:

Each core extracted from Seabrook Unit 1 will be subjected to a petrographic analysis to detect internal microcracking and delamination.

Finally, both C-10 and NextEra agreed that crack index monitoring is an initial monitoring technique to be applied to ASR-degraded concrete. 1168 As for a more thorough analysis, the Board notes that the above license condition is consistent with the FHWA Report that states

[t]he quantitative assessment of the extent of cracking through the [c]racking [i]ndex, along with the [p]etrographic [e]xamination of the cores taken from the same affected element, [are] used as tools for the early detection of ASR in the concrete. 1169 1168 Tr. at 494 (Saouma), 510-11 (Simons).

1169 See NER013, FHWA Report at 3 (italics omitted).

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Official Use Only Proprietary Information F. C-10s Remaining Issues Are Outside the Scope of the Proceeding

1. Deformation Monitoring Seabrooks Structures Monitoring Program (SMP), as relevant to the LAR, has two distinct partsExpansion Monitoring, which involves collecting ASR expansion measurements from Seabrook structures for monitoring against specified acceptance criteria based on the LSTP; and Deformation Monitoring, which requires gathering in-situ data for monitoring against thresholds established in the structural evaluations. 1170 Deformation Monitoring in the SMP evaluates external loads and monitors their effects on structures using FEA considering ASR expansion and other effects such as creep, shrinkage, and swelling. 1171 NextEra asserted that Dr. Saouma raise[d] a host of new issues and challenges related to structural evaluations, the [SEM], [FEA], and [structural deformation monitoring . . . [that]

could have been, but were not, raised at the outset of this proceeding. 1172 Moreover, NextEra asserted that testimony challenging the treatment of ASR expansion as a design basis load is new and entirely unrelated to the representativeness of the LSTP. 1173 Further, NextEra alleged it developed the approach of calculating ASR loads and load factors independent of the 1170 Ex. NER001, MPR Testimony at 59, 111-13; see Ex. NER007, Seabrook [SMP] Manual Rev. 7 at 4-1.2 (non-public).

1171 Ex. NER007, Seabrook [SMP] Manual Rev. 7 at 4-1.1 to -1.3 (non-public); Ex. NER004, SGH Testimony at 16 (Evaluations of structural adequacy are exercises to determine whether the demands (i.e., load effects) on a structure or its elements exceed the capacities (e.g.,

strength or stress limits) of the structure or its elements. Methods of determining appropriate demands and capacities are prescribed by specific criteria, standards, and codes. For Seabrook, these methods are described in its [Ex. NRC007,] UFSAR at Section 3.8.).

1172 NextEra MIL 2 at 19.

1173 Id. at 18. However, Dr. Saouma withdrew this argument at the hearing. Tr. at 440 (Saouma).

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Official Use Only Proprietary Information LSTP. 1174 NextEra maintained that none of those issues are sufficiently related to the representativeness of the LSTP to be considered within the scope of this proceeding. 1175 C-10 argued that Dr. Saoumas arguments are properly before the Board. 1176 Furthermore, C-10 maintained that both the monitoring program for ASR progression and the monitoring program for structural deformation depend on the LSTP, and that both provide input to and assumptions for the FEA relied on by NextEra. 1177 Accordingly, C-10 asserted that NextEra incorrectly argued that the Deformation Monitoring Program and FEA have no relevance to the reformulated contention. 1178 We emphasize that there is a distinction between the capacity and demand calculations used in the FEA, which is a component of Deformation Monitoring. We have held that the capacity side of the FEA (i.e., the assumption that capacity should be calculated using the code equations and the original material properties) is within the scope of this proceeding. 1179 However, we find the demand side analysis of the FEA, concerning the calculation of structural loads in addition to ASR loads, beyond the scope of the proceeding. Therefore, NextEras Motion in Limine, as it pertains to FEA and Deformation Monitoring, is granted in part, and denied in part.

No quantitative data from the LSTP was used as a direct input into the FEA. 1180 We therefore conclude that the demand side equations of the FEA are beyond the scope of this 1174 NextEra MIL 2 at 18 (citing Ex. NER004, SGH Testimony at 17-18).

1175 Id. at 18-20.

1176 See generally C-10 Opp. to MIL 2.

1177 Id. at 14-19.

1178 Id. at 15.

1179 See supra Part VIII.A.5.a.

1180 Ex. NER004, SGH Testimony at 17-18 (No specific measurements, calculations, data, or other information from the LSTP are direct inputs into the SEM or structural evaluations; and

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Official Use Only Proprietary Information proceeding. The ASR loads developed for each ASR-affected structure at Seabrook are estimated based on in-situ data, using CCI and other measurements, from Seabrook structures, unrelated to the LSTP. 1181 SGH developed the approach of calculating ASR loads and load factors independent of the LSTP. 1182 The use of CCI, as relevant to determining ASR loads in the FEA, is similarly beyond the proceedings scope. 1183 The only overlap of the structure[al]

deformation monitoring program with the LSTP is that its use of code-based structural capacity acceptance criteria is tied to the point at which a structure would meet the expansion limits identified in the LSTP. 1184 Therefore, we agree with NextEra and hold the demand side equations of the FEA, concerning design basis loads and load factors, are independent of the LSTP and beyond the scope of this proceeding. We grant the Motion in Limine as to section C.2.4.3 of Dr. Saoumas pre-filed testimony, as well as section D.9.2 of Dr. Saoumas rebuttal testimony, 1185 because they are outside the scope of the reformulated contention and the Boards reformulated contention. 1186 nothing from the LSTP informed any baseline assumptions on the demand side of the equations for the SEM or the structural evaluations.); Ex. NRC001-R, Staff Testimony at 21-23.

1181 Ex. NRC001-R, Staff Testimony at 21 ([T]he ASR load developed in this manner with respect to each ASR-affected structure at Seabrook is estimated based on field data from the actual structures and is not derived from the LSTP.); Tr. at 901 (Bolourchi) ([T]he amount of the expansion you simulate . . . comes from CCI measured in the field[.]).

1182 Ex. NER004, SGH Testimony at 17-18.

1183 Our earlier analysis which addressed CCI did so in the context of the LSTP, whereas here, CCI is used to gather in-situ data from the plant to inform the demand side of the FEA, which is beyond the scope of this proceeding. See supra Parts VIII.A.1-A.2.

1184 Ex. NRC001-R, Staff Testimony at 22.

1185 Ex. INT027, Dr. Saouma Pre-Filed Testimony § C.2.4.3; Ex. INT032, Dr. Saouma Rebuttal Testimony § D.9.2.

1186 We need not rule on the appropriateness of Ex. INT027 § C.2.4.2, in which C-10 argued that NextEra confuses capacity and demand because Dr. Saouma withdrew the argument during the hearing. See Tr. at 440 (Saouma).

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Official Use Only Proprietary Information Insofar as Dr. Saouma presented additional challenges to the FEA, we find they are all beyond the scope as part of the demand side analysis. 1187 To be clear, the only aspect of the FEA we are considering is the use of the original code capacities. Since we already discussed the use of the original code capacities, supra Part VIII.A.5, there is nothing remaining to resolve regarding this matter.

2. Inadequate Peer Review NextEra argued C-10s testimony regarding a lack of peer review should be excluded from the record for three reasons. 1188 First, the argument is new and was not mentioned in the Petition. Second, and alternatively, if the argument is not new, it is included within the subject of testimony found inadmissible as part of Contention E. 1189 Third, peer review is unrelated to representativeness. 1190 For its part, C-10 argued NextEras failure to conduct peer review is relevant to the adequacy of the [LSTP] and the monitoring program[.] 1191 We agree with NextEra and exclude Dr. Saoumas testimony related to peer review from the record.

All parties offered arguments as to whether NextEra and the Staff obtained adequate peer review of the LAR, and whether peer review is necessary. 1192 Peer review might have 1187 Ex. INT001-R, Dr. Saouma Pre-Filed Testimony at 23-29 (non-public); Ex. INT027, Dr.

Saouma Pre-Filed Testimony at 23-29; Ex. INT032, Dr. Saouma Rebuttal Testimony at 42; Ex.

INT007, Dr. Saouma Review of Selected Documents at 9-19 (non-public); Ex. INT031, Dr.

Saouma Review of Selected Documents at 10-19.

1188 NextEra MIL 2 at 14-15.

1189 Id. at 14-15, 14 n.58. Contention E challenge[d] NextEras use of proprietary information drawn from the [LSTP] in the LAR, arguing that the use of such information is not good science, creates an air of secrecy that prevents review, and undermines . . . trust within the nearby communities[.] LBP-17-7, 86 NRC at 131 (quoting C-10 Petition at 11).

1190 NextEra MIL 2 at 14-15.

1191 C-10 Opp. to MIL 2 at 11; see also Ex. INT027, Dr. Saouma Pre-Filed Testimony at 36.

1192 C-10 Opp. to MIL 2 at 11 ([N]either NextEra nor the NRC Staff had followed the standard scientific method of obtaining an independent peer review of their work.); NextEra MIL 2 at 14 n.59 ([I]f C-10 had raised this issue [of peer review] at the outset, it would have been rejected as immaterial (because there is no requirement for peer review in 10 C.F.R. Part 50) and as demonstrably unsupported [throughout the record.]); see NRC Staffs Proposed Findings of Fact and Conclusions of Law at 36-40.

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Official Use Only Proprietary Information allowed the scientific and engineering community to provide input to improve the LSTP.

However, a lack of peer review is not a specific issue with a component of the LSTP, such as specimen size or concrete mineralogy. Peer review, by itself, is not a representativeness issue.

It therefore does not fall within the scope of the reformulated contention, Contention D as a basis of that reformulated contention, or any of the other admitted contentions that comprise the bases of the reformulated contention. Because the testimony advocating peer review challenged the processes of establishing the LSTP and drafting the LAR but did not challenge a specific component of the LSTP for a lack of representativeness, we grant NextEras Motion in Limine and will not consider the peer review issue further.

The Board also notes that NRC regulations in 10 C.F.R. Part 50 do not require that a license amendment request, or any analysis that supports such request, be submitted for peer review. 1193 Thus, had this issue been alleged in the C-10 Petition, it likely would not have been admitted because it would not have been material to the Staffs decision in reviewing the LAR. 1194 We therefore grant NextEras Motion in Limine regarding peer review.

3. Steel Corrosion NextEra moved to exclude C-10s testimony on the subject of steel corrosion. 1195 Specifically, NextEra argued that the Board found the topic of steel corrosion was beyond the 1193 See Ex. NRC001-R, Staff Testimony at 73-74; NextEra MIL 2 at 14 n.59.

1194 The Board notes that the phrase peer review was mentioned in C-10s Petition, however it was stated in a passing manner and did not equate to an argument alleging a lack of peer review. In fact, the reference to peer review was made in the context of proposed Contention E, which we found wholly inadmissible. See C-10 Petition at 11 (It is difficult to understand how withholding pertinent information, which would allow an independent assessment of the test results used to support the claims of NextEra, could reasonably be interpreted in this way. It is usual to actually submit such results for peer review to provide a basis for consensus among the relevant scientific community.); LBP-17-7, 86 NRC at 131-32; see also NextEra MIL 2 at 14 nn.58-59.

1195 NextEra MIL 2 at 9.

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Official Use Only Proprietary Information scope of the proceeding in dismissing Contention F. 1196 Contention F stated elevated levels of salt . . . [have] likely created the conditions for corrosion of reinforcing steel[.] 1197 NextEra argued that Dr. Saoumas statement that testing for free chloride concentrations is important to make sure that it is below critical limits before steel [depassivates] (i.e. corrode) 1198 is simply reiterat[ing] the argument previously rejected by the Board in Contention F. 1199 C-10, however, argued that Contention F challenged the monitoring of the rebar, whereas here, Dr. Saoumas argument for testing the concentration of free chloride is focused on monitoring concrete. 1200 Further, C-10 argued that testing for the free chloride concentration is included within the admissible purpose of determining the required comprehensive petrographic analysis of in-situ concrete[.] 1201 We agree with NextEra and exclude the testimony of steel corrosion. 1202 C-10 failed to base its steel corrosion argument on a deficiency in the LAR and instead asserted that an alternative methodology should be implemented. In addition, C-10s attempt to distinguish the present testimony from that proffered in support of Contention F is unpersuasive.

At its core, both arguments, although stated differently, are concerned with the corrosion of steel rebar. Dr. Saouma advocated for the testing of the free chloride concentration for one 1196 Id.; see LBP-17-7, 86 NRC at 132-33.

1197 C-10 Petition at 12.

1198 Ex. INT027, Dr. Saouma Pre-Filed Testimony at 22 (Because of the proximity of the sea, concrete should be tested for its (free) chloride concentration and make sure that it is below critical limits before steel [depassivates] (i.e. corrode).); Ex. INT032, Dr. Saouma Rebuttal Testimony at 36 ([S]aline solution could easily find its way through the ASR-induced cracks, depassivating the steel rebar (according to Faradays law), and causing corrosion (Hansen and Saouma, 1999)[.]).

1199 NextEra MIL 2 at 9.

1200 C-10 Opp. to MIL 2 at 5-6.

1201 Id. at 6 (quoting LBP-17-7, 86 NRC at 112).

1202 See supra note 1198.

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Official Use Only Proprietary Information purposeto make sure it will not cause corrosion of the rebar. 1203 That is the exact subject we found inadmissible in Contention F. 1204 Further, as noted in our ruling on contention admissibility, the SMP contains a separate program for monitoring rebar that was not revised in the LAR. 1205 Therefore, for the aforementioned reasons, we grant NextEras Motion in Limine to exclude testimony on the topic of testing for chloride concentration.

G. Unaddressed Issues We reviewed the voluminous record associated with this proceeding and weighed the evidence presented and the parties positions. The above discussions capture all of the material issues within the scope of the proceeding. To the extent we did not address an argument raised by C-10, we found it immaterial to the findings we must make.

IX. Conclusion A. Summary of Board Holdings and License Conditions The Board finds that the following conditions are necessary for the NextEra requested license amendment to satisfy regulatory requirements and so these conditions are added to License No. NPF-86, Amendment No. 159, Appendix C:

c. NextEra shall undertake the monitoring required by MPR-4273, Appendix B, Check 3, for control extensometers every six months, rather than in 2025 and every ten years thereafter.

1203 The salt-induced corrosion of rebar, which is beyond the scope of the reformulated contention, is distinct from the ASR-induced cracking of rebar, which was addressed earlier, supra Part VIII.A.5; see Ex. INT027, Dr. Saouma Pre-Filed Testimony at 22 (Because of the proximity of the sea, concrete should be tested for its (free) chloride concentration and make sure that it is below critical limits before steel [depassivates] (i.e. corrode).).

1204 LBP-17-7, 86 NRC at 132-33.

1205 Id. at 133 (The plants rebar is already subject to a monitoring program that is not being altered in this LAR); see Ex. NER007, Seabrook [SMP] Manual Rev. 7 at 1-1.2, 2-1.1 (non-public).

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d. If stress analyses conducted pursuant to the SEM show that the stress in the rebar from ASR-induced expansion and other loads will exceed the yield strength of the rebar, NextEra must develop a monitoring program sufficient to ensure that rebar failure or yielding does not occur, or is detected if it has already occurred, in the areas at-risk of rebar failure or yielding.

e. If the ASR expansion rate in any area of a Seabrook seismic Category I structure significantly exceeds 0.2 mm/m (0.02%) through-thickness expansion per year, NextEras Management will perform an engineering evaluation focused on the continued suitability of the six-month monitoring interval for Tier 3 areas. If the engineering evaluation concludes that more frequent monitoring is necessary, it shall be implemented under the SMP.

f. Each core extracted from Seabrook Unit 1 will be subjected to a petrographic analysis to detect internal microcracking and delamination.

Subject to the listed conditions, the Board resolves the reformulated contention in favor of NextEra. With the addition of these necessary conditions to License Amendment No. 159, the Board concurs with the Staff that NextEras proposed method to evaluate seismic Category I structures affected by ASR is acceptable and provides reasonable assurance that these structures [will] continue to meet the relevant requirements of 10 [C.F.R.] Part 50, Appendix A, GDC 1, 2, 4, 16 (containment only) and 50 (containment only) and 10 [C.F.R.] Part 50, Appendix B. 1206 B. Review of the Boards Decision In accordance with 10 C.F.R. §§ 2.1210, 2.1212, and 2.341, this initial decision will constitute a final decision of the Commission 120 days after its issuance unless: (1) a party files 1206 Ex. INT024, Final SE at PDF 69.

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Official Use Only Proprietary Information a petition for Commission review within twenty-five (25) days after service of this initial decision; or (2) the Commission directs otherwise. Within twenty-five (25) days after service of a petition for Commission review, parties to the proceeding may file an answer supporting or opposing Commission review. Unless otherwise authorized by law, a party to an NRC proceeding must file a petition for Commission review before seeking judicial review of an agency action. 1207 IT IS SO ORDERED.

THE ATOMIC SAFETY AND LICENSING BOARD

/RA/

Ronald M. Spritzer, Chairman ADMINISTRATIVE JUDGE

/RA/

Nicholas G. Trikouros ADMINISTRATIVE JUDGE

/RA/

Dr. Sekazi K. Mtingwa ADMINISTRATIVE JUDGE Rockville, Maryland August 21, 2020 1207 10 C.F.R. § 2.1212.

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Official Use Only Proprietary Information APPENDIX GLOSSARY OF TERMS 1208 Aggregate Particulate material, commonly gravel and sand, that is mixed with cement and water to produce concrete. Aggregate sizes can be coarse (large) or fine (small), with concrete mixture designs using a spectrum of aggregate sizes.

Alkali-Silica Reaction A chemical reaction that can occur in (ASR) concrete and produce an expansive gel that results in cracking and may eventually cause structural distress.

Axial compression Forces that compress (i.e., squeeze) a structural element together. Excessive axial compression loading will cause the element to crush.

Beam (one-way) Shearing forces are unaligned forces that shear push one part of the element in one direction and another part of the element in another direction. Forces applied in parallel planes that are some distance apart create compression and tension fields. Excessive one-way shear produces a diagonal failure plane between the unaligned, opposite forces.

Capacity Ability of a structural member to withstand applied load.

Chemical In the context of ASR, chemical Prestressing prestressing is a means for producing continuous compressive stress in reinforced concrete by virtue of ASR expansion being restrained by embedded reinforcement.

Compression A load applied to a structural member that is in the direction of pushing the constituents together; i.e., crushing. In other words, a compression load works to reduce the size of the component.

Prestressed Concrete A special form of reinforced concrete in which reinforcing steel (i.e., prestressing steel) is 1208 See Ex. NER002, MPR Glossary at 1-4.

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Official Use Only Proprietary Information tensioned against the concrete (putting concrete in compression.) The application of compression load to a concrete member improves its service performance by limiting tensile stresses or cracking resulting from those tensile stresses. The compressive stress from prestressing (i.e.,

precompression) must be completely overcome before the concrete member will be exposed to net tensile stress.

Combined Cracking A term used at Seabrook Station for a Index (CCI) combination of Cracking Index values in both the horizontal and vertical directions.

Cracking Index A crack width summation technique for (CI) quantitatively estimating tensile strains experienced by a reinforced concrete element. The Cracking Index is the ratio of the sum of crack widths to the length of which the crack summation activity is performed (i.e. the gauge length.)

Crack Width A technique for estimating expansion of a Summation reinforced concrete element by measuring the widths of cracks along a line (or lines) of defined length.

Damage Rating A technique for characterizing ASR Index (DRI) progression during petrographic examination by assigning a quantitative score to characterize certain features associated with ASR. The cumulative result is the DRI.

Demand Potential load(s) that could be applied to a structural member.

Extensometer A device for monitoring expansion into the depth of a concrete member that is embedded in a borehole drilled into concrete.

Finite Element Analysis (FEA) The FEA is a computational model that includes various elements to collectively simulate the structural geometry, stiffness, and mass of the desired structure. Modelers can add loads (i.e., demands), such as gravity, wind, or ASR, to the FEA to measure structural responses.

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Official Use Only Proprietary Information Flexure A force that causes a structural element to bend. Compression is applied on the inside radius of the bent member and tension is applied on the outside radius. For a concrete member, which is typically weaker in tension, excessive flexure loading will cause the element to split or tear on the tension side.

In-Plane Expansion Expansion that occurs in the two dimensions of a concrete member that are visibly accessible at the surface. At Seabrook Station and in the LSTP test specimens, the in-plane directions are also parallel to the embedded reinforcement mats.

Limit state A behavioral mode by which a structural response is examined. In structural design, each limit state must be evaluated to confirm structural adequacy. For example, a reinforced concrete component must be sufficiently strong in flexure, shear, etc.

Normalized Elastic The ratio of the modulus of elasticity of ASR-Modulus affected concrete to the original elastic modulus. This parameter is the input variable for the correlation to determine through-thickness expansion prior to instrument installation.

Plain concrete Concrete without reinforcing bars, or unreinforced concrete.

Petrographic evaluation Microscopic examination of prepared concrete surfaces by a qualified petrographer. The examination assesses the overall quality of concrete and can determine causes for concrete degradation.

Punching (two-way) For punching shear, force is applied locally, shear rather than in a uniform plane. In other words, a punching shear condition exists when a structural wall or a reinforced concrete slab is patch-loaded. An excessively patch-loaded area will result in critical levels of shear stresses and will eventually puncture the structural element in the vicinity of the patch-loaded area.

Reinforcement The bond between the concrete to the anchorage embedded reinforcement that allows load to

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Official Use Only Proprietary Information transfer from the concrete to the reinforcing bars. A loss of reinforcement anchorage would cause the reinforcing bars to slip within the concrete element. For reinforced concrete elements to behave in a manner consistent with the design principles, all reinforcement needs to be anchored.

Reinforcing bars Steel bars embedded in concrete to increase (Rebar or Rebars) the capacity of the structural members to withstand design loads. Since concrete is strong in compression and weak in tension, the primary use of reinforcing bars is to reinforce the tension side of reinforced concrete elements.

Reinforcement ratio The cross-sectional area of reinforcing bars divided by the entire cross section of the reinforced concrete structural member. This calculation determines the fraction of a reinforced concrete section occupied by reinforcement.

Representativeness The ability to apply conclusions from one application to inform circumstances in another application. In the context of the admitted contention, representativeness refers to the results from the LSTP and their applicability to reinforced concrete structures at Seabrook Station.

Seismic Category I Structures at a nuclear power plant that must Structures fulfill their design function following a design basis seismic event.

Shear A loading condition where unaligned forces push one part of a structural member in one direction and another part of the member in another direction, creating a diagonal compression and tension field. Excessive shear forces produce a diagonal failure plane that runs between the applied load and a support reaction in a typical shear test.

Tension A load applied to a structural member that is in the direction of pulling the constituents apart. In other words, a tensile load works to elongate, or increase the size of, a structural component.

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Official Use Only Proprietary Information Through-thickness Expansion that occurs in the dimension of a expansion concrete member that is not visibly accessible at the surface, i.e., expansion in the direction through the surface. At Seabrook Station and in the LSTP test specimens, the through-thickness direction is not reinforced (except for the lower portion of the Containment structure).

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UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION In the Matter of )

)

NEXTERA ENERGY SEABROOK, LLC ) Docket No. 50-443-LA-2 (Seabrook Station, Unit 1) )

)

(License Amendment) )

CERTIFICATE OF SERVICE I hereby certify that copies of the foregoing INITIAL DECISION (Ruling on the Reformulated Contention) (LBP-20-09)have been served upon the following persons by Electronic Information Exchange.

U.S. Nuclear Regulatory Commission U.S. Nuclear Regulatory Commission Office of Commission Appellate Adjudication Office of the Secretary of the Commission Mail Stop: O-16B33 Mail Stop: O-16B33 Washington, DC 20555-0001 Washington, DC 20555-0001 ocaamail.resource@nrc.gov Hearing Docket hearingdocket@nrc.gov U.S. Nuclear Regulatory Commission Atomic Safety and Licensing Board Panel U.S. Nuclear Regulatory Commission Mail Stop: T-3F23 Office of the General Counsel Washington, DC 20555-0001 Mail Stop: O-14A44 Washington, DC 20555-0001 Ronald M. Spritzer, Chair Administrative Judge Anita Ghosh, Esq.

ronald.spritzer@nrc.gov anita.ghosh@nrc.gov Jeremy Wachutka, Esq.

Nicholas G. Trikouros jeremy.wachutka@nrc.gov Administrative Judge David E. Roth, Esq.

nicholas.trikouros@nrc.gov david.roth@nrc.gov Dr. Sekazi K. Mtingwa Administrative Judge sekazi.mtingwa@nrc.gov OGC Mail Center: Members of this office have received a copy of this filing by EIE service.

Taylor Mayhall, Law Clerk Taylor.Mayhall@nrc.gov Molly Mattison, Law Clerk Molly.Mattison@nrc.gov Ian R. Curry, Law Clerk Ian.curry@nrc.gov Stephanie Fishman, Law Clerk stephanie.fishman@nrc.gov

NEXTERA ENERGY SEABROOK, LLC (Seabrook Station Unit 1) - Docket No. 50-443-LA-2 INITIAL DECISION (Ruling on the Reformulated Contention) (LBP-20-09)

NextEra Energy Seabrook, LLC C-10 Research & Education Foundation 801 Pennsylvania Avenue, N.W., #220 44 Merrimac Street Washington, DC 20004 Newburyport, Mass. 01950 Steven C. Hamrick, Esq. Natalie Hildt Treat steven.hamrick@fpl.com natalie@c-10.org NextEra Energy Seabrook, LLC Harmon, Curran, Spielberg, & Eisenberg, LLP Morgan, Lewis & Bockius LLP 1725 DeSales Street, NW, Suite 500 1111 Pennsylvania Avenue NW Washington, DC 20036 Washington, DC 20004 Diane Curran, Esq.

Paul M. Bessette, Esq. dcurran@harmoncurran.com paul.bessette@morganlewis.com Scott David Clausen, Esq.

Scott.Clausen@morganlewis.com Ryan K. Lighty, Esq.

ryan.lighty@morganlewis.com Grant Eskelsen, Esq.

grant.eskelsen@morganlewis.com Digitally signed by Clara I. Sola Clara I. Sola Date: 2020.09.10 15:48:15

-04'00' Office of the Secretary of the Commission Dated at Rockville, Maryland, this 10th day of September 2020.

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