SBK-L-16071, Sg&H Report 160268-R-01 Development of ASR Load Factors for Seismic Category I Structures (Including Containment) at Seabrook Station. Seabrook, Nh Revision 0

Sg&H Report 160268-R-01 Development of ASR Load Factors for Seismic Category I Structures (Including Containment) at Seabrook Station. Seabrook, Nh Revision 0

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SBK-L-16071 ENCLOSURE4 SG&H Report 160268-R-01 Development of ASR Load Factors for Seismic Category I Structures (Including Containment) at Seabrook Station. Seabrook, NH Revision 0 (Seabrook FP# 101039)

REPORT APPROVAL SHEET SIMPSON GUMPERTZ & MEGER I Engineering of Struc tures o nd Building Enc losures Client: NextEra Energy Project No. 160268 Project: Susceptibility Evaluation of Category I Structures at Seabrook Station, Seabrnok, NH Report No.: 160268-R-01 Report Type: Full Report

Title:

Development of ASR Load Factors for Seismic Cateuory I Structures (Including Containment) at Seabrook Station, Seabrook, NH Number of pages Including this page: 1 + 33 + 3 fAtt. 11 =37 Are there unverified assumptions (Y/N): ....

N.___ _ __

Is this report safety-related per contract (Y/N): _,_

Y_ _ _ __

Objective:

Develop ASR load factors for Seismic Gategory I structures at Seabrook consistent with the methodology of the original design basis documents.

Revision Descriptions 0 Initial document Revision Preparer I Date lndep. Verifier I Date Approver I Date 0

7JW!/J1J~

Michael Mudlock Glenn R. Bell Said Bolourchl 07/27/2016 07/27/2016 07/27/2016 EP 3.5 EX 3.1 RO Date: 6 Aug 2014

Table of Contents Letter of Transmittal CONTENTS Page Table of Contents EXECUTIVE

SUMMARY

3

1. INTRODUCTION 6 1.1 Objective 6 1.2 Background 6 1.3 Scope 7 1.4 l<ey Terms and Definitions 7 1.4.1 Alkali-Silica Reactivity 7 1.4.2 Cracking Index and Combined Cracking Index 8 1.4.3 ASR Severity Zones 8 1.4.4 Reliability Index 9 1.5 Revision History 9 1.5.1 Revision 0 9

2. DEVELOPMENT OF ASR LOAD FACTORS FOR SEISMIC CATEGORY I STRUCTURES OTHER THAN CONTAINMENT 10 2.1 Approach to Establish ASR Loading 10 2.2 Results of Document Review 10 2.3 Methodology 11 2.3.1 ASR Categorization 11 2.3.2 Development of ASR Load Factors 11 2.4 Assumptions 12 2.5 Summary 13

3. DEVELOPMENT OF ASR LOAD FACTORS FOR THE CONTAINMENT BUILDING14 3.1 Approach to Establish ASR Load Factors 14 3.2 Results of Document Review 14 3.3 Methodology 15 3.4 Assumptions 16 3.5 Summary 16

4. DEVELOPMENT OF ASR LOAD FACTORS FOR THE INTERIOR CONTAINMENT STRUCTURES 17 4.1 General 17 4.2 Summary 17

5.

SUMMARY

AND CONCLUSIONS 18

6. TABLES 19

7. FIGURES 24

8. REFERENCES 25 Report No. 160268-R-01 Revision O

APPENDICES APPENDIX A - Crack Index Measurement Data as of 1 April 2016 APPENDIX B - Independent Verification ATTACHMENTS ATTACHMENT 1 - EXTERNAL PEER REVIEW DOCUMENTATION Report No. 160268-R-01 Revision 0

EXECUTIVE

SUMMARY

The Seabrook Updated Final Safety Analysis Report (UFSAR) and accompanying documents define the loading and acceptance criteria used to establish the licensing basis for Seabrook Station (Seabrook) [Ref. 1). These documents do not address the effects of alkali-silica reactivity (ASR), which was identified to occur at Seabrook. ASR is a chemical reaction that can occur in concrete under certain conditions and cause cracking and expansion in unrestrained or partially restrained structures, systems, and components (SSCs). ASR can affect SSCs by creating additional loading and/or altering concrete material properties.

An examination of the design standards defined in the UFSAR and applicable to the original design of the Seismic Category I structures at Seabrook led to the development of ASR load factors. Factored ASR demands should be used in combination with other design loadings specified in UFSAR Tables 3.8-1, 3.8-14, and 3.8-16. NextEra Energy (NEE) investigated the effects of ASR on concrete material properties at Seabrook in a separate study [Ref. 4).

The primary conclusions of the review of the design basis documents and development of ASR load factors are as follows:

o The reinforced concrete Seismic Category I structures other than the Containment Building (CB) were designed in accordance with ACI 318-71 [Ref. 6). The CB was designed in accordance with ASME Boiler and Pressure Vessel Code, Section Ill -

Division 2, 1975 (Ref. 7) . The reinforced concrete Interior Containment Structures were designed in accordance with ACI 318-71 .

o By using inspection data collected from more than twenty Seismic Category I structures throughout Seabrook and properly categorizing ASR-related cracking into four zones that correspond to parameters currently used in the Seabrook Structural Monitoring Program, load factors for ASR-related strains (demands) have been developed for use in evaluation of the Seismic Category I structures, including the CB, at Seabrook.

o For reinforced concrete Seismic Category I structures other than the CB, typically use ASR load factors of 2.0 for ASR effects in combinations with static loads, 1. 7 for those with static plus wind loads, and 1.3 for those with static plus seismic loads.

o Reduce the ASR load factors by 25% when ASR effects are combined with thermal or other transient loading .

o Use an ASR load factor of 1.0 when ASR effects are combined with unusual loads, such as the safe-shutdown earthquake (SSE).

o When ASR strains are greater than 0.05% (0.5 mm/m), the ASR load factors may be reduced by 20%, but shall not be taken as less than 1.0.

o For the CB, use an ASR load factor of 1.0 for all load combinations.

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o For reinforced concrete Containment Internal Structures, use ASR load factors similar to those for reinforced concrete Seismic Category I structures other than the CB, except that ASR load factors developed for wind load combinations are not applicable.

o For initial screening evaluation of the CB, use conservative ASR strain demands based primarily on visual observations. If detailed analysis is needed, make Cl measurements and reduce the conservatism in the ASR demands as permitted in Table 3.

o The conclusions reported herein apply to all Seismic Category I structures located at Seabrook when the severity of ASR is below the level at which material properties begin to degrade as established by the large-scale testing program conducted at FSEL

[Ref. 4].

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SYMBOLS AND NOTATIONS ACI American Concrete Institute ASME American Society of Mechanical Engineers ASR Alkali-Silica Reaction B&PV Boiler and Pressure Vessel p Reliability Index CB Containment Building CCI Combined Cracking Index CEB Containment Enclosure Building Cl Crack Index D Dead Load Eo Operating Basis Earthquake FSEL Ferguson Structural Engineering Laboratory (The University of Texas at Austin)

H Static Lateral Earth Pressure He Dynamic Lateral Earth Pressure kASR Ratio of Factored ASR Demand to Total Factored Demand L Live Load NEE NextEra Energy OBE Operating Basis Earthquake RCE Root Cause Evaluation Sa Loading from ASR SGH Simpson Gumpertz & Heger Inc.

SSC Structure, System, and Component SSE Safe Shutdown Earthquake UFSAR Updated Final Safety Analysis Report Report No. 160268-R-01 Revision O

1. INTRODUCTION Chapter 1 provides an introduction to the work presented in this document. Section 1.1 identifies the objective of the document. Section 1.2 provides background on the need for development of ASR load factors. Section 1.3 identifies the scope of work, and Section 1.4 defines several key terms used in this document.

1.1 Objective The objective of this report is to summarize the development of appropriate load factors for alkali-silica reactivity (ASR) and their use in structural evaluation of all Seismic Category I structures, including the Containment Building (CB), at Seabrook.

1.2 Background In accordance with the Seabrook UFSAR [Ref. 1), the reinforced concrete Seismic Category I structures other than the CB were designed in accordance with the strength design methodology of ACI 318-71 [Ref. 6). The CB was designed in accordance with ASME Boiler and Pressure Vessel Code, Section Ill - Division 2, 1975 [Ref. 7). The reinforced concrete Interior Containment Structures were designed in accordance with ACI 318-71 .

Table 3.8-16 of the Seabrook UFSAR defines the load combinations used in the original design of the Seismic Category I structures other than the CB. Table 3.8-1 of the Seabrook UFSAR defines the load combinations used in the original design of the CB. Table 3.8-14 of the Seabrook UFSAR defines the load combinations used in the original design of the Interior Containment Structures. Neither of these tables includes effects of ASR, which NEE discovered to occur at Seabrook and can negatively affect a structure, system, or component (SSC) by creating additional loading, causing unwanted deformation, and altering concrete material properties.

The physical manifestation of ASR, in the form of cracking and effects of bulk/global deformation is documented and reviewed under the NEE-Seabrook Structural Monitoring Program. In 2014, NEE identified evidence of apparent movement of the Containment Enclosure Building (CEB) and prompted a Root Cause Evaluation (RCE) of apparent deformation of the CEB. The RCE determined that ASR was the prime contributor to global structural deformations.

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ASR can create an external load and/or an internal load on an SSC. As an external load, ASR-induced expansion of concrete backfill outside of a structure may create pressures and/or deformations not anticipated in the original design basis. Internal expansion of reinforced concrete may produce cracking, deformation, and tension in steel reinforcement and compression in concrete not anticipated in the original design basis.

The effects of ASR on concrete material properties have been examined through a research and large-scale physical testing program conducted at the Ferguson Structural Engineering Laboratory (FSEL) at the University of Texas at Austin. Key findings from that effort are reported in Reference 4 and include the following:

o Combined Cracking Index (CCI) methodology, particularly the procedure used at Seabrook, provides a reasonable approximation of true engineering strain and is an acceptable methodology for monitoring in-plane expansion .

o Material properties and design code-based relationships such as shear strength of concrete, anchorage to concrete capacity, and performance of reinforcement lap splices, were not reduced in ASR-affected concrete with in-plane expansion levels significantly higher than those observed at Seabrook.

These conclusions support the use of Cl/CCI in approximating in-plane expansion and the use of design basis properties and code-based strength relationships in evaluating the Seabrook structures for effects of ASR.

1.3 Scope This report provides load factors for ASR to augment the original design basis load combinations defined in Tables 3.8-1, 3.8-14, and 3.8-16 of the Seabrook UFSAR to be used with appropriate acceptance criteria.

1.4 ~{ey Terms and Definitions The following paragraphs define technical terms used in this document to explain the development of ASR load factors.

1.4.1 Alkali-Silica Reactivity Alkali-silica reactivity (ASR) is a chemical reaction between the alkali content contained in cement and reactive silica minerals contained in some concrete aggregates. The reaction produces a gel that swells if moisture is present. ASR can be identified through petrographic examination and is often indicated in service by random map cracking.

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1.4.2 Cracking Index and Combined Cracking Index The Cracking Index (Cl) is a crack mapping process to quantitatively characterize the severity of cracking . It includes measurement and summation of crack widths along a set of perpendicular lines on the surface of a concrete element being investigated and then normalizing these values in each direction for comparison to other conditions. The Federal Highway Administration (FHWA) uses the Cl method in conjunction with petrography to investigate deterioration of concrete elements. The Combined Cracking Index (CCI) is an alt13rnative metric closely related to Cl to express the severity of cracking by normalizing the cracking in both directions. A typical ASR-monitoring location produces two Cl values and one CCI value.

Cl and CCI at Seabrook are used to characterize the severity of cracking on concrete structures. Values are typically reported in mm/m. As noted in Reference 4, the CCI methodology provides a reasonable approximation of true engineering strain and is an acceptable methodology for monitoring in-plane expansion. Seabrook Cl and CCI values are converted to % strain by dividing the values by 10, e.g., CCI =1.0 mm/m =0.1% strain.

1.4.3 ASR Severity Zones ASR severity zones are fou r categories established to identify reg ions of a structure based on representative Cl measurements of ASR cracking . Table 1 provides the limits of each zone.

The lowest three zones (Zone I, Zone II , and Zone Ill) are established to align with the criteria for Tier 1: Acceptable with Deficiencies - Qualitative Monitoring Required, Tier 2: Acceptable with Deficiencies - Quantitative Monitoring and Trending Required , and Tier 3: Unacceptable -

Structural Evaluation Required as defined in the Seabrook Structural Monitoring Program (SMP)

(Ref. 3). The fourth zone (Zone IV), which represents regions with the highest amount of ASR-related cracking, falls within the SMP Tier 3 criteria and is established herein to set the upper limit on Zone Ill for use in structural evaluation and development of ASR load factors. Cl measurements below the lower limit of Zone I (< 0.1) imply a strain less than 0.01 %, which is less than 5% of the yield strain of ASTM A615 Grade 60 reinforcement. These strains are judged to be negligible, and portions of the structure categorized into this zone are expected to meet the SMP Tier 1 - Acceptable criteria.

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1.4.4 Reliability Index Reliability Index ({1) is a statistical metric often used in structural engineering to establish or evaluate the difference between strength and load. Reliability Index and limit state probability are inversely related , so a structure with a high reliability index has a low probability of failure.

Reliability Index is defined as shown below.

P = Z/<1z Where z is a function that defines the excess strength with respect to the combined load effect, and where Z < O represents structural deficiency. In this definition, z and <Jr. are the mean and standard deviation of Z, respectively. For some probability distributions, such as normal and log-normal, a closed-form equation for p is known. In cases where a closed-form equation is not known, f3 may be computed using Monte Carlo simulation, in which a statistically significant number of sample strength and load values are randomly generated, and the probability of failure and reliability index can be computed directly.

1.5 Revision History 1.5.1 Revision 0

• Initial document Report No. 160268-R-01 . 9- Revision 0

2. DEVELOPMENT OF ASR LOAD FACTORS FOR SEISMIC CATEGORY I STRUCTURES OTHER THAN CONTAINMEN Chapter 2 describes the development of ASR load factors for the reinforced concrete Seismic Category I structures other than the CB. Section 2.1 identifies the approach taken to establish the ASR load factors. Section 2.2 summarizes the results of a review of relevant documents.

Section 2.3 describes the methodology used to develop the ASR load factors . Section 2.4 identifies assumptions incorporated into the methodology and provides justification for use, and Section 2.5 summarizes the key results of the study.

2.1 Approach to Establish ASR Loading Efforts to develop ASR load factors for reinforced concrete Seismic Category I structures other than the Containment Building should result in values that maintain the reliabi lity levels that were found [Ref. 2) to be inherent in the original design code, ACI 318-71 [Ref. 6). Although the introduction of ASR loads represents an increase to the total demands acting on the structures, it is still possible to maintain the code intended reliability indices since the original design usually is based on conservative assumptions and analyses, and as a result provides an additional margin compared to code requirements. To achieve this goal, NEE took the following approach:

• Perform a critical review of ACI 318-71 and associated documents to establish the reliability inherent in the original design codes.

• Aggregate the inspection data showing the presence and severity of ASR throughout the facility and characterize it in a manner useful for structural evaluation.

o Account for the variety and complexity of the load combinations stated in the design basis documents.

2.2 Results of Document Review The literature review into the basis of the ACI 318-71 load combinations identified a document by Ellingwood et al. [Ref. 2) that explored the basis for the construction of load combinations and then back-calculated reliability indices for pre-1980s design codes. Ellingwood et al. found that the reliability indices implied in pre-1980s design codes were, on average, 3.0, 2.5, and 1.75 for static, wind, and seismic load combinations, respectively. Additionally, Reference 2 is the basis for the current probability-based limit state design requirements in ASCE/SEI 7

[Ref. 11], ACI 318 [Ref. 12), and ANSl/AISC 360 [Ref. 13).

Also included in Ellingwood et al. are key statistical parameters used in the development of ASR load factors . Ellingwood et al. define the ratio of mean to nominal resistance (R/Rn) as 1.05 for Report No. 160268-R-01 Revision O

flexure and 1.09 for shear. The authors also define the coefficient of variation of resistance (VR) as 0.11 for flexure and 0.17 for shear. These parameters are included in Table 4 of SGH Document 160268-CA-01 [Ref. 8] as part of a summary of computation inputs used to develop ASR load factors for reinforced concrete Seismic Category I structures other than the CB.

2.3 Methodology 2.3.1 ASR Categorization Based on findings from the research performed at FSEL (Ref. 4] and elsewhere [Ref. 5], Cl measurement data will be used to establish the distribution and severity of ASR in each of the reinforced concrete structures at Seabrook. The data will be reviewed to define ASR regions on each structure, with each region being represented by a mean ASR Cl value for each in-plane direction. Each region will be categorized into one of the four ASR severity zones shown in Table 1.

2.3.2 Development of ASR Load Factors The most recent set of Cl measurements at each available monitoring grid as of 1 April 2016 is considered to develop ASR load factors. The data come from 108 grids (total of 216 data sets, when considering two orthogonal directions), which are located on more than twenty different structures or components at Seabrook. The data was collected on a range of different structural elements, such as walls, floors, roofs, etc., and incorporate both interior and exterior exposures.

Table A 1 of Appendix A provides a summary of each of the grids that includes the structure, exposure, date of latest measurement, and Cl values as of 1 April 2016.

Log-normal probability distributions to represent the data within each ASR severity zone identified in Table 1 are developed . The distributions were fit to match the mean and standard deviation of the data within each zone and were adjusted to provide conservatism. Section 4.1 of SGH Document 160268-CA-01 [Ref. 8] provides technical details of this process.

With the ASR effects now characterized, the next step is to account for the variability in the ASR and non-ASR demands, both of which vary between structures and within a structure. The ACI 318-71 design code uses factored load combination demands for non-ASR loads.

Therefore, the ASR load should also have a load factor to be added to the original load combination groups.

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To address the variability in the factored loading, two load configurations are developed - one that concentrates the non-ASR demand in lateral loads and another more evenly between lateral and gravity loads. The calculations presented in Ref. 8 showed the final results were insensitive to the selection of load configurations.

To further address loading variability and recognizing that ASR demands associated with each of the severity zones vary in magnitude and in relation to non-ASR demands, a parameter, kAsR.

is defined to represent the ratio of factored ASR demand to total factored demand. This kAsR ratio varies from 0.4 at Zone I (lowest ASR severity) to 1.0 at Zone IV (highest ASR severity).

Figure 1 shows that the required load factors for ASR in Zone I increases as a function of kAsR.

and that static load combinations (which target a reliability index of 3.0) generally require higher load factors than wind and seismic load combinations (which target reliability indices of 2.5 and 1.75). Figure 2 shows that ASR load factors associated with Zone II are lower than those in Zone I; this is because ASR loads in Zone II (as well as Zones Ill and IV) have a significantly lower coefficient of variation than those in Zone I. In fact, ASR load factors selected for Zone I at a kAsR ratio of 0.4 are conservative relative to the load factors at all ratios in Zones II through IV. This finding indicates that a region of a structure with concrete falling into Zone II or higher (i.e., with Cl of 0.5 mm/m and higher) have larger ASR demands, but require a smaller ASR load factor to meet the target reliability indices because the ASR variability in these higher zones is lower. The final selected load factors are presented in Table 2 for each of the design basis load combinations.

Sections 6 and 7 of SGH Document 160268-CA-01 provide a more detailed discussion of the methodology, including the definition and use of statistical terminology and computations used to generate and verify the ASR load factors.

2.4 Assumptions As stated in the previous section, the methodology includes the use of log-normal probability distributions to represent the ASR Cl data within a given severity zone. Curves fit through the data were examined, and the curves were adjusted to ensure that they produced equivalent or conservative results compared to the unadjusted curves.

Computation of reliability indices with log-normal distributions uses a closed-form solution method that incorporates some simplifying assumptions. A Monte Carlo simulation performed for one set of parameters that includes 100,000 randomly computed resistances, non-ASR Report No. 160268-R-01 Revision 0

demands, and ASR-related demands, verified that the approach used to calculate reliability indices is valid and produces reasonable results.

The methodology uses two bounding load configurations to proportion non-ASR demands within design basis load combinations. The results showed that the computation of ASR load factors was insensitive to the selection of the proportions of factored loads.

2.5 Summary The following summarizes the key results for development of ASR load factors for the reinforced concrete Seismic Category I structures other than the CB:

o Use Cl grids coupled with visual inspection to determine the severity of ASR.

o Characterize regions of each of the structures into one of the four defined ASR severity zones identified in Table 1 based on the mean Cl measurements in a particular region .

o Apply ASR load factors in accordance with Table 2. This table is based on Table 3.8-16 of the Seabrook UFSAR and includes an additional (highlighted) column showing ASR load factors for each of the required design load combinations. Also added to the UFSAR table is Note 5, which states that when ASR strains are greater than 0.05%

(0.5 mm/m), the ASR load factors may be reduced by 20% but shall not be taken as less than 1.0.

• The methodology presented in this chapter represents a rational analysis and maintains the reliability that is inherent to ACI Standard 318-71 .

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3. DEVELOPMENT OF ASR LOAD FACTORS FOR THE CONTAINMENT BUILDING Chapter 3 describes the development of ASR load factors for the CB. Section 3.1 identifies the approach taken to establish the ASR load factors . Section 3.2 summarizes the results of a review of relevant documents. Section 3.3 describes the methodology used to develop the ASR load factors. Section 3.4 identifies assumptions incorporated into the methodology and provides justification for use, and Section 3.5 summarizes the key results of the study.

3.1 Approach to Establish ASR Load Factors Efforts to develop ASR load factors for the CB must result in values that maintain the level of performance that is inherent to the original design code, 1975 ASME Boiler & Pressure Vessel Code (B&PV) [Ref. 7). To achieve this goal, NEE took the following approach:

o Perform a critical review of the 1975 ASME B&PV and associated documents to understand the reliability intended by the original code authors.

o Aggregate the inspection data showing the presence and severity of ASR within the CB and characterize it in a manner useful for structural evaluation.

• Account for the variety and complexity of the load combinations stated in the design basis documents.

3.2 Results of Document Review The literature review of relevant documents showed that Table 3.8-1 of the Seabrook UFSAR

[Ref. 1) is based on Table CC-3230-1 of the 1975 ASME B&PV. The ASME B&PV Code is generally based on working stress design and elastic behavior with limited inelastic behavior allowed under certain conditions. Article CC-3000, Design, requires consideration of loads and compliance with corresponding limit states under Service load and Factored load conditions.

Under Service load conditions, which represent conditions during construction and normal plant operation, all load factors are 1.0, and service-level limit states apply. Factored loads incorporate severe and extreme environmental and abnormal/accident conditions that act infrequently. Most loads are factored by 1.0, but some are factored by 1.25, 1.3, or 1.5 as part of specific combinations. Limit states are significantly higher for Factored conditions than for Service conditions.

The literature review found that the loads and load factors in ASME B&PV Table CC-3230-1 are deterministic and were developed in the early to mid-1970s through the judgment of knowledgeable and experienced code-writers. The code-writers recognized the uncertainty in loading; they included load factors of 1.25 and 1.5 for the OBE and other factors greater than Report No. 160268-R-01 Revision O

1.0 for live load, accident pressure, and rupture of high-energy pipe in particular load combinations. However, the load factor for the SSE is always 1.0 since a larger earthquake was not deemed credible.

Additional discussion is provided in Section 2 of SGH Document No. 160268-L-01 [Ref. 9].

3.3 Methodology The primary intent of the methodology is to develop ASR loads that have a very small likelihood of exceedance and use an ASR load factor of 1.0. This approach for ASME code-checking, of using an extreme loading with a load factor of 1.0 is fundamentally different from reliability-based approaches commonly used in codes such as ACI 318 (and which are employed for the Non-containment Category 1 structures), where mean load values are used with a load factors greater than 1.0. This different approach is appropriate for ASME code-checking for two reasons:

(1) It is consistent with the deterministic philosophy used in the development of ASME Table CC-3230-1 .

(2) The limited CCI measurements on the Containment Building do not allow a probabilistic approach to load-factor determination.

Similar to the methodology described to develop ASR load factors for the Seismic Category I structures other than the CB, NEE will use visual survey and Cl measurements to determine the presence and distribution of ASR in the CB. The existing Cl data will be reviewed to understand the current distribution and severity of ASR in the CB.

Once the data are collected and reviewed, the CB or regions will be categorized into one of the four ASR severity zones shown in Table 1. As a conservative approach to account for the variability in visual inspections and Cl measurements, the maximum Cl value in each of the regions will be used to categorize a particular region into an ASR severity zone.

For an initial screening evaluation that will primarily rely upon visual observations rather than Cl measurements, the strain loads associated with the ASR severity zone boundaries shown in Table 1 are expanded by 25% as shown in the second and third columns of Table 3. If the screening evaluation results in overstressed portions of the structure, NEE may make additional inspections and Cl measurements and rezone the potential problem area(s). A detailed evaluation may then be performed with ASR strain loads in the rezoned area based on the highest Cl measurement in the zone without the 25% increase, using the values in the fourth Report No. 160268-R-01 Revision O

and fifth columns in Table 3. For all evaluations of the CB, NEE will use the appropriate strain limits as ASR-related demands with a load factor of 1.0 in combination with other factored design basis loadings.

Similar to the methodology used to develop ASR load factors for the Seismic Category structures other than the CB, NEE will regularly monitor the exterior surface of the CB for changes in ASR severity, and reanalyze as conditions warrant.

3.4 Assumptions The primary assumption inherent in the methodology discussed above is that determining appropriate ASR severity zones for the CB through visual inspection and crack measurements is somewhat subjective but achievable. This assumption is partially addressed by the fact that NEE-approved inspectors have been performing Cl measurements in accordance with NEE-approved written procedures [Ref. 10]. In addition, conservatively selecting design strain limits for each zone provides margin to account for variability in visual observations and crack measurements.

3.5 Summary The following summarizes the key results for development of ASR load factors for the CB:

o Use Cl grids coupled with visual inspection to determine the severity of ASR.

• For an initial conservative screening evaluation, characterize regions of the CB into one of the four defined ASR severity zones identified in Table 1 based on the maximum CCI value in that zone, and use the expanded strain limits for evaluation (Columns 2 and 3 of Table 3) .

o If the screening evaluation identifies potential problem areas, make additional Cl measurements, rezone the CB as warranted, and reevaluate the CB using the strain limits identified in Columns 4 and 5 of Table 3. While the analysis will typically use the strain values at the high end of the zones to evaluate a particular region, use the strain demands at the low end of the range in adjacent or other regions where appropriate if they produce a more severe confining effect on the region under review.

• Use an ASR load factor of 1.0 for all load combinations as shown in Table 4.

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4. DEVELOPMENT OF ASR LOAD FACTORS FOR THE INTERIOR CONTAINMENT STRUCTURES Chapter 4 describes the development of ASR load factors for the reinforced concrete Interior Containment Structures. Section 4.1 summarizes the approach, and Section 4.2 summarizes the key results.

4.1 General Table 3.8-14 of the Seabrook UFSAR [Ref. 1] indicates that the load combinations applicable to the Interior Containment Structures are based on ACI 318-71 [Ref. 6]. Therefore, the approach used and methodology followed to develop ASR load factors for the reinforced concrete Interior Containment Structures are similar to those described in Chapter 2 for the reinforced concrete Seismic Category I structures other than the CB. Given these similarities, the proposed ASR load factors applicable to Interior Containment Structures design load combinations are similar.

Because the Interior Containment Structures are located inside the CB, loadings such as earth pressure, wind, and tornado effects do not apply. This allows a reduction and simplification of the design load combinations. Table 5 presents ASR load factors for load combinations applicable to the design of the Interior Containment Structures.

4.2 Summary Similar to the approach described in Chapter 2 for the reinforced concrete Seismic Category I structures other than the CB:

o Use Cl grids coupled with visual inspection to determine the severity of ASR.

• Characterize regions of each of the reinforced concrete Interior Containment Structures into one of the four defined ASR severity zones identified in Table 1 based on the mean Cl measurements in a particular region .

o Apply ASR load factors in accordance with Table 5. This table is based on Table 3.8-14 of the Seabrook UFSAR and includes an additional (highlighted) column showing ASR load factors for each of the required design load combinations. Also added to the UFSAR table is Note 5, which states that when ASR strains are greater than 0.05% (0.5 rnrn/m), the ASR load factors may be reduced by 20% but shall not be taken as less than 1.0.

o The methodology presented in this chapter represents a rational analysis and maintains the reliability that is inherent to ACI Standard 318-71 .

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5.

SUMMARY

AND CONCLUSIONS The primary conclusions of this study are as follows :

o The reinforced concrete Seismic Category I structures other than the Containment Building (CB) were designed in accordance with ACI 318-71 [Ref. 6]. The CB was designed in accordance with ASME Boiler and Pressure Vessel Code, Section 111 -

Division 2, 1975 [Ref. 7] . The reinforced concrete Interior Containment Structures were designed in accordance with ACI 318-71 .

o By using inspection data collected from more than twenty Seismic Category I structures throughout Seabrook and properly categorizing ASR-related cracking into one of four zones that correspond to parameters currently used in the Seabrook Structural Monitoring Program, ASR-related strains (demands) and load factors have been developed for use in evaluation of each of the Seismic Category I structures, including the CB, at Seabrook.

o For reinforced concrete Seismic Category I structures other than the CB, typically use ASR load factors of 2.0 for ASR effects in combinations with static loads, 1.7 with static plus wind loads , and 1.3 with static plus seismic loads.

o Reduce the ASR load factors by 25% when ASR effects are combined with thermal or other transient loading.

• Use an ASR load factor of 1.0 when ASR effects are combined with unusual (extreme) loads, such as the safe-shutdown earthquake (SSE).

• When ASR strains are greater than 0.05% (0.5 mm/m), the ASR load factors may be reduced by 20%, but shall not be taken as less than 1.0.

• For the CB, use an ASR load factor of 1.0 for all load combinations.

o For reinforced concrete Containment Internal Structures, use ASR load factors similar to those for reinforced concrete Seismic Category I structures other than the CB, except that ASR load factors developed for wind load combinations are not applicable.

o For initial screening evaluation of the CB, use conservative ASR strain demands based primarily on visual observations. If detailed analysis is needed, make Cl measurements and reduce the conservatism in the ASR demands as permitted in Table 3.

o The conclusions reported herein apply to all Seismic Category I structures, including the CB, located at Seabrook when the severity of ASR is below the level at which material properties begin to degrade as established by the large-scale testing program conducted at FSEL [Ref. 4).

Report No. 160268-R-01 Revision O

6. TABLES Table 1 - ASR Severity Zones Visua l Appearance of ASR Relative ASR Cracking Indicative of Cl in Comparable Seabrook SMP Zone Severity Indicated Range (mm/m l ASR Crack Criteria***

I Low Cl< 0.5* Tier 2 Qualitative II Moderate 0.5 s Cl< 1.0 Tier 2 Quantitative Ill High 1.0 s Cl< 2.0 Tier 3 IV Very HiQh >2.0..

• Cl < 0.1 can be ignored for CB evaluation since categorization is based on maximum Cl.

.. Cl = 3.5 mm/mused as upper limit for all Seismic Category I structures other than the CB .

... Seabrook SMP ASR criteria are based on CCI, rather than Cl values used herein.

Report No. 160268-R-01 Revision 0

0 Table 2 - Category I Structures Other Than CB or Its Internals Basic Load Combinations and Load

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Table 3 - ASR-Related Strain Loads for Analysis of the CB Strain Load (%) for Screening Strain Load (%) for Detailed Evaluation Evaluation Zone Low Hi~h Low Hi~h I 0.01 0.06 0.01 0.05 II 0.04 0.13 0.05 0.10 Ill 0.08 0.25 0.10 0.20 IV 0.15

• 0.20 **

• The high strain load for Zone IV 1s to be 25% greater than the largest observed strain in the zone from Cl measurements and/or visual inspection .

The largest observed strain in the zone from Cl measurements may be used.

Report No. 160268-R-01 Revision 0

0 CD "C

Table 4 - Containment Building Bas ic l oad Combinations and l oad Factors 0

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'" lncludcs cm~ct of nonn:il opcr:ning thcrm:il lo:1ds and :iccidcnt lo.:ids. For all :1bnonn:d l1>:1d condition$. structure ~hould be checked to :i~~ure th::n xddcnt pressure to.id without thcrm:il lo=ad c.:in be f'C:'(isted by the .structure wi thin the ~iticd :1.Uow:1b1c strcs:r.o for thi!C. condition.

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• • \ Sec Su~ion 3Jt t _1 for di:4C\ll(.<ion of1o:uiinS".

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.., BC l.O 1.0 l.0 1.0 1.0 1.0 1.0  !.O 1.0 1.0 l.O (F, e Allow~blc Stri:ss) 1!

• Sec Subsection 3.S.3.J for discussion of looding.'I.

In :ibovc lo:id combinations. the ric:ik v:iluc:s or J>,. T*. R.,. R,,. R,,. R.~ :uid M sh:ill be combined (when they :ic1 concurr<'1111y) unk-ss time hi,'tory :in~lysis is performed to j ustify otherwise.

0 '" For these !o:id combin:itions either d:istic or pl:istic d<-.i;,-n may be used.

Lood combin:i1ions 7S. SS. 7C :ind SC :in: :ilso checked without R... R.,. R_.

(1) "'

< 151 Where ASR strains arc greater than 0.05% (0.5 mm/m), ASR load factors may be reduced by 20% but shall not be tnken as Jess than 1.0.

(ii' Ci'

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0

7. FIGURES ASR Load Factors for Zone I I I llU Static Load Combiu3!ion (farget Reliability Ind' x .. 3.0)

+++ Wind I.o.!.d Combination (farget Reliability Index = 2.5)

Sei ~mic OBE Load Combinaticm (farget Reliability Jude.x "" 1.75) 4 3

2 0.1 0.2 0.3 0.4 0.5 0.6 0.7 O.S 0.9 R!tio of Factored ASR Demand to Total Demand Figure 1 - Impact of Ratio of ASR Demands to Total Demands on ASR Load Factor for Zone I [Ref. 8]

ASR Load Factors for Zone II 6 I ICHHI Static Load Combination (farget Reliability Index= 3.0) i

+++ Wind load Combination (farget Reliability Index= 2.S) I

++o Seismic OBE Load Combination (Target Reliability Index"" Ln) I I I I I I! I lI I

lI I

2 i

...l l

... .-i . _ _.

~

• t--

T l'.l-

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I I I

0.1 0.2 0.3 0.4 0.5 0.6 0.7 o.s 0.9 Ratio of Factored ASR Demand to Tola! Demand Figure 2 - Impact of Ratio of ASR Demands to Total Demands on ASR Load Factor for Zone II [Ref. 8]

Report No. 160268-R-01 Revision 0

8. REFERENCES

1. Seabrook Station, Updated Final Safety Analysis Report, Revision 12.

2. Ellingwood , B., et al., Development of a Probability Based Load Criterion for American National Standard A58, NBS Special Publication 577, June 1980.

3. NextEra Energy Seabrook, "Technical Procedure - Structural Monitoring Program 36180, Attachment 3," Revision 06, Sept. 2015.

4. MPR Associates, "Seabrook Station - Implications of Large-Scale Test Program Results on Reinforced Concrete Affected by Alkali-Silica Reaction ," MPR-4273, Apr.

2016.

5. Mohammed, T.U.. H. Hamada, and T. Yamaji, "Alkali-Silica Reaction-Induced Strains over Concrete Surface and Steel Bars in Concrete," AC/ Materials Joumal, Vol. 100 No. 2, Mar.-Apr. 2003.

6. American Concrete Institute Committee 318, Bllilding Code Requirements for Reinforced Concrete (ACI 318-71), Detroit, Ml , 1971 .

7. ACl-ASME Joint Committee, American Concrete Institute, ASME Boiler and Pressltre Vessel Code, Section Ill, Division 21ACI Standard 359-74, Code for Concrete Reactor Vessels and Containments, Detroit, Michigan I American Society of Mechanical Engineers, New York, NY, 1975.

8. Simpson Gumpertz & Heger Inc.. "Computation of Load Factors for ASR Demands for Seismic Category I Structures Other Than Reactor Containment", SGH Document No.

160268-CA-01, Revision 0, July 2016.

9. Simpson Gumpertz & Heger Inc .* SGH Document No. 160268-T-001, Revision 0, July 2016.

10. Simpson Gumpertz & Heger Inc.. "Cracking Index (Cl) Determination, SGH 2014-13 Revision 2, 27 May 2015.

11. American Society of Civil Engineers, Minimum Design Loads for Bllilclings and Other Structures, ASCE/SEI 7-10, Reston, VA, 2010.

12. American Concrete Institute Committee 318, Building Cocie Requirements for Structural Concrete (ACI 318-11), Farmington Hills, Ml, 2011 .

13. American Institute of Steel Construction, Specification for Structural Steel Buildings, ANSllAISC 360-10, Chicago, IL, 22 June 2010.

l\sgh.com\O fficeslBOSIProjects\201 61160268.00*SUSA\Worksp ace\Oevelop_ASR_Load_Facto r\summary report\Rev 0\ 160268*R* 01 RevO.docx Report No. 160268-R-01 Revision 0

Appendix A Crack Index Measurement Data as of 1 April 2016 Prepared By: Verified By:

1<r-~

Ryan M. Mones 11W1f/JJM Michael Mudlock Report No. 160268-R-01 - A-1 of A Revision 0

Table A 1 - Crack Index Measurement Data Afil.ll.I Qlli..ill1 Reference Grid Label Structure Exposure Placement Direction Direction (mm/ml Imm/ml Measured Document CBAZ*317 Containment Building lnrerlor Wall Horizontal Vertical 0.43 0.34 Feb. 2012 110594-SVR*Ol *RO CElO l *Ol Containment Building Interior Wall Horizontal Vertical 0.43i0.11 0.71+/-0.13 Aug. 2014 120555*SVR*l7*RO CE101*02 Containment Building Interior Wail Horizon tal Verllcal 0.5010.13 0.79+/-0.11 Aug. 2014 120555*5VR* 17*RO MF102*01 Containment Building Interior Wall Horizontal Vertical 1.Bli0.19 1.6210.20 Dec. 2015 120555*SVR*2B*RO CElOl*OlA (Cl-10) Containment Enclosure Building Interior Wall Horizontal Vertical 0.1710.05 0.2410.07 Jan. 2015 120555*SVR*23*RO CEI01*02A (Cl -15) Containment Enclosure Building Interior Wall Horizontal Vertical 0.1710.05 0.7910.13 Jan. 2015 120555-SVR*23*RO CEBE*Ol5 Containment Enclosure Building Exterior Wall Horizont*I Vertical 0.6710.16 0.82+/-0.20 Apr. 2014 120555*SVR* 13*RO CEBl*Ol Containment Enclosure Building Interior Wall Hori zon tal Vertical 0.95+/-0.16 1.16+/-0.21 Oct. 2015 120555-SVR-27-RO Cl-1 Containment Enclosure Building Interior Wall Horizonlal Vertical 0.19 0.08 Oec. 2011 110594-CA*Ol*RO Cl *ll Containmen t Enclosure Building Interior Wall Horizontal Vertical 0.28 0.50 Dec. 2011 110594-CA*Ol*RO Cl -12 Containment Enclosure Building Interior Wall Horizontal Vertical 0.11 0.39 Dec. 2011 110594-CA*Ol*RO Cl-13 Containment Enclosure Building Interior Wall Horizontal Vertlcal 0.72 0.14 Dec. 2011 110594*CA*Ol*RO Cl -14 Containment Enclosure Building Interior Wall Horizon tal Vertical 0.08 0.03 Dec . 2011 l10S94*CA*Ol *RO Cl-2 Containment Enclosure Building Interior Wall Hori zontal Vertical 0.19 0.06 Dec. 2011 110594-CA*Ol*RO Cl*3 Containment Enclosure Building Interior Wall Horizontal Vertical 0.06 0.00 Dec. 2011 110594-CA*Ol *RO Cl-4 Containment Enclosure Building Interior Wall Horizontal Vertical 0.08 0.08 Dec. 2011 110594-CA*Ol*RO Cl-5 Containment Enclosure Building Interior Wall Horizontal Vertical 0.14 0.14 Dec. 2011 110S94*CA*Ol*RO Cl-6 Containment Enclosure Building Interior Wall Horizontal Vertical 0.14 0.03 Dec. 2011 110594-CA*Ol*RO Cl-7 Containment Enclosure Building Interior Wall Horizonlal Vertical o.os 0.06 Dec. 2011 110594*CA*Ol *RO Cl*8 Containment Enclosure Building Interior Wall Horizontal Vertical 0.22 0.08 Dec. 2011 110594 *CA:o1-Ro Cl*9 Containment Enclosure Building Interior Wall Horizontal Vertlcal 0.11 0.14 Dec. 2011 110594*CA*Ol *RO CBE*Ol Control and Diesel Generator Bldg. Exterior Wall Horizontal Vertical 0.6110.15 0.58i 0.15 Aug. 2014 120555*SVR*17*RO DGlOl-01 Control and Diesel Generator Bldg. Interior Wall Horizontal Verlical 0.40+/-0.08 1.0010.16 Aug. 2014 120555-SVR-17-RO DG102-01A Control and Diesel Generator Bldg. Interior Wall Horizontal Vertical 0.27+/-0.05 l.2li0.13 Aug. 2014 1205SS*SVR*17*RO DG102*01B Control and Diesel Generator Bldg. Interior Wall Horizontal Vertical 0.2210.06 0.9910.14 Aug. 2014 120555*SVR*l7*RO DGE*Ol Control and Diesel Gentrator Bldg. Exterior Wall Horizontal Vertical 0.8810.19 0.53+/-0.12 Aug. 2014 12055S*SVR*17*RO SGH Cl*DGB Control and Diesel Generator Bldg. Interior Wall Horizontal Vertical 0.6610.10 1.4910.25 Dec. 2015 120555*SVR*28*RO MF20S-Ol East Pipe Chase Exterior Wall Horizontal Vertical 0.3810.10 0.54+/-0.13 l\ug. 2014 120555-SVR* l l*RO Report No. 160268-R-01 - A-2 of A-5* Revision O

Table A 1 - Crack Index Measurement Data A!!tl ll!!.ti. &i!.li.I Date last Reference Grid label Structure Exposure Placement Direction Direction (mm/ml Measured Document MF206-0l fast Pipe Chase Interior Wall Horizontal Vertical 0.8lt0.10 0.90!0.13 Jan. 2015 l20555*SVR*23*RO MF207-01 fast Pipe Chase Interior Slab E*IV N-5 1.41t0.22 1.1310.20 Dec. 2015 120555 *SVR*28*RO MF302*01 East Pipe Chase lnteiior Slab tl *S E*W 0.99+/-0.19 J.S3i 0.17 Dec. 2015 120555-5VR*28*RO MF303-0l East Pipe Chase Interior Slab E*W tl *5 2.07+/-0.20 2.26+/-0.lS Dec. 2015 120S55 *SVR*28*RO MF304*01 rast Pipe Chase Interior Wall Horizontal Vertical 0 .8610.10 0.69i 0.14 Jan. 2015 120S5S-SVR*23*RO MFE*Ol East Pipe Chase Exterior Wall Horizontal Vertical 1.13+/-0.16 0.35! 0 .09 Dec. 2015 120SSS*SVR* 28*RO C8ST1*01 Electrkal Cable Tunnels Interior Wall Horizontal v.. tical 0.lH0.03 0.77!0.20 Aug. 2014 120555*SVR* 17*RO C8ST1-Q2 Electrical Cable Tunnels Interior Wall Horizontal Vertical 0.4810.13 O.SH0.11 Aug. 2014 120SSS*SVR* l7*RO EF101*01 Elect rical Cable Tunnels Interior Slab £*\'/ N*S 1.36!0.38 0.6l:t0.16 Dec. 2015 12055S *SVR*28*RO EF102 *01 Electrical Cable Tunnels Interior Wall Horizonta l Vertical 0.83!0.15 0.81+/-0.IS Aug. 2014 120555*SVR*17-RO EF202*01 Electrlcal Cable Tunnels Interior Wall flor irontai Vertical 0.78+/-0.13 0.7H0.1S Aug. 2014 120S5S*SVR*17*RO MFIOl*OlA El ectrical Cable Tunnels Interior Wall Horirontai Vertica l 0.8510.15 2.13:10.27 Dec. 201S 120555-SVR-28-RO MflOl*OIA lndex2 Electrical Cable Tunnels Interior Wall Horizontal Vertical 0.60!0.06 l.32:t0.25 Dec. 2015 120S55*SVR*28*RO MflOl*OlB Electrical Cable Tunne ls Interior Wall Horizontal Vertical 0.24+/-0.05 1.0710.13 Aug. 2014 120S55*SVR* 17*RO MF101*01C Electrical Cable Tunnels Interior Slab EW N*S 1.32!0.27 0.6910.15 Dec. 2015 120S55*SVR*28*RO MF201-0l Eleclrical Cable Tunnels Interior Slab N*S E*W 0.2810.08 0.19+/-0.05 Jun. 2015 120SSS*SVR*25*RO SGH Cl-BET Electrical Cable Tunnels Interior \Vall Hori?ontal Vertical 0.86+/-0.17 1.5810.31 Dec. 2015 120555 -SVR-28-RO Cl.WOHVall Electrical Vaults Exterior Wall Hor irontal Vertical 1.7110.13 2.0710.14 Dec. 2015 120555*SVR*28*RO Cl-\V04 -Wall Electrkal Vaults hterlor Wall Hor izontal Vertical 1.0410.09 0.8510.10 Oct. 2014 120S5S-SVR*19*RO Cl*\VOS*Wall Electr k al Vaults Exterior \Vall Horl1ontal Vertical 0.24+/-0.0S 1.5510.12 Dec. 2015 120S55*SVR*28*RO Cl-W06 -Wall Electrical Vaults Exterior Wall Horirontal Vertical 1.3310.13 1.0810.13 Dec. 201S 1205S5-SVR*28*RO Cl*W07*\Vall Electrical Vaults Exterior Wall Horirontal Vertical 0.89!0.14 0.96:10.15 Oct. 2013 120SSS*SVR*09*RO Cl*W08-Wall Electrical Vaults hterior Wall Horizontal Vertical 0.81i0.13 0.8210.12 Oct. 2014 120SS5*SVR*l9*RO Cl*\VlO*Wall Electrical Vaults Exterior Wall Hor ltontal Vertical 0.61t0.07 0.6810.10 Nov. 2014 1205SS*SVR* l9*RO Cl-Wll*Ceillng Electrkal Vaults Exterior Slab N*S HV 0.Sli0.08 0.4510.09 Oct. 2013 120SSS*SVR*09*RO CIWll*Wall Eloctrlcal Vaults Exterlor Wall Hori1ontal Vertical 1.1210.13 1.3410.17 Dec. 2015 1205S5-SVR*28*RO

£Fl03*01 Emergency Feed water Pump Bldg. Interior Wall Horizontal Vertical 0 .4610.08 0.7310.12 Jun. 201S 120SSS*SVR-25*RO EFE*Ol Emergency Feed water Pump Bldg. Exterior Wall llorizonlal Ve rtical 0.40+/-0.09 0.74+/-0.17 Aug. 2014 120555-SVR* l7*RO Report No. 160268-R-01 *A-3 of A-5* Revision O

Table A 1 - Crack Index Measurement Da ta Aili..lll Date last Reference Grid label Structure Exposure Placement Direction Direction (mm/ml !mm/ml Measured Document EFST-01 Emergency feed water Pump Bldg. Interio r Wall Horizontal Vertical 0.57!0.12 1.44i 0.22 Dec. 2015 120555-SVR-28-RO SGH Cl* EfW Emergency Feed water Pu mp Bldg. Interior Wall Horizontal Vertical 0.88i0.17 0.9610.18 Dec. 2015 120555-SVR-28-RO fBlOS*Ol Fuel Storage Building Interior Wall Horizontal Vertical 1.02!0.08 0.67:LO. ll Aug. 2014 120555-SVR-17-RO fB106*02 Fuel Storage Building Interio r Wall Horizonta l Vertical 0.3310.07 0.6910.10 Aug. 2014 l20555*SVR*17*RO fBl06*03 Fuel Storage Building Interior Wall Horizontal Vertical 0.3410.06 1.50+/-0.23 Aug. 2014 120555-SVR-17-RO fSBE*Ol fue l Storage Building Exterior Wall Horizontal Vertical 0.5810.10 0.34+/-0.09 Aug. 2014 120555-SVR-l 7-RO MF103*02 Mechanical Penetration Interior Wall Horizontal Ver tica l 1.0410.26 2.27+/-0.37 Dec. 2015 120555-SVR-28-RO MFIOS*Ol Mechanical Penetr a lion Interior Wall Horizontal Vertical 2.2710.25 1.7610.20 Dec. 2015 120555-SVR-28-RO PAVRE*Ol Pre-Action Valve Building Exterior Wall Ho ri zontal Vertical 0.5110.12 0.5410.13 Aug. 2014 l2055S*SVR* l7*RO PABE*Ol Pr imary Auxiliary Building Exterior \Vall Horizontal Vertical 0.42i0.09 0.21!0.05 Aug. 2014 120555-SVR-17-RO PB103-01 Primary Au*iliary Building Interior Wall Horizontal Vertical 1.3310.23 l .03+/-0.22 Dec. 2015 120555-SVR-28-RO PB20S*Ol Primary Auxiliary Building Interior Wall Hor i1ontal Vertical 2.1710.38 3.25+/-0.36 Dec. 2015 120555-SVR-28-RO RHREVR*Ol RHRVaul t Exterior Slab N*S E*\11 0.5810.12 0.97i0.16 Dec. 2015 120555*SVR*28*RO RVlOl-01 RHRVault Interior Wall Horizontal Vertical 0.82+/-0.15 1.48+/-0.20 Dec. 2015 120555-SVR-28-RO RV102 *01 RllRVault Interior Wall Horizontal Vertical 0.40+/-0.12 0.53+/-0.16 Aug. 2014 120555-SVR-17-RO RV30 1*01 RHRVault Interior Wall Horitontal Verllcal 1.09+/-0.23 3.00+/-0.54 O<>c. 2015 120555 -SVR-28-RO RV302-0l RHRVault Interio r Wall Horizontal Vertical 0.96i0.22 1.8210.43 Dec. 2015 120555-SVR-28-RO RVST2-0l RHRVault Interior Wall Horizontal Ver tical 1.3310.31 1.SH0.37 Dec. 2015 120555 -SVR-28-RO CTlOl-01 Service \\later Cooling Tower Interior Wall Horizontal Vertica l 0.5310.15 0.37+/-0.11 Aug. 2014 120555-SVR*l 7-RO CT102*01 Service \Valer Cooling Towe r Interior Wall Horizontal V<rtica l 0.9410.23 0.9410.23 Aug. 2014 120555-SVR-17-RO CT104-0l Service Water Cooling Tower Interior \Vall Horizontal Vertical 0.1910.05 0.6110.09 Jan. 2015 120SSS*SVR*23*RO CTE*OJN Service Water Cooling Tower Exterior Wall Horizontal Vertical 1.9210.28 0.6110.13 Dec. 2015 120555-SVR-28-RO CTE-015 Service Water Cooling Tower Exterior Wall Hortzontal V<>rtical 1.0810.17 1.2U0.16 Dec. 2015 120555-SVR-28-RO CTE-025 Se rvice Water Cooling Tower Exterior Wall Horizontal Vertical 0.7210.17 0.7410.18 Dec. 2015 l20555*SVR*28*RO Mf202*02 West Pipe Cha se Exterior Wall Horizontal Vertical 0.97.t0.19 1.2210.21 Dec. 2015 120555-SVR-28-RO MF203*01 West Pipe Chase Interior Slab E*W N*S 0.6010.13 0.6010.13 Oec. 2015 120555-SVR-28-RO Mf204-0l West Pipe Chase Interior Slab SW*llf SE*NW 2.0910.13 2.4510.30 Dec. 2015 120555-SVR-28-RO CST!Ol -01 Condensate Storage Tank Interior Slab E-\V N*S 1.37+/-0.19 1.2010.16 Dec. 2015 120555-SVR*28*RO Report No. 160268-R-01 -A-4 of A Revision 0

Table A 1 - Crack Index Measurement Data Axis 1 fil!tl A!!lll1 rul1.li! .l!fil.1lil IWllifil.t Grid label Structure Exoosure Placement Direction Direttlon (mm/ml (mm/ml Measured Document CST101*01A Condens*te Stonge Tank Interior Wall Horizon tal Vertical 1.26+/-0.13 0.5810.13 Jan. 2015 120555*SVR*23 *RO CSTE*Ol Condensate Stonge Tan k Exter ior Wall Horizontal Vertk*I 1.2510.29 0.8H0.18 Dec. 2015 120555*SVR*28*RO CSTR*Ol Conden .. te Storage Tan k Exter ior Slab E*W N*S 1.30!0. I 5 1.0810.14 Aug. 201 4 120555*SVR* l 7-RO DSE*Ol Oischorge Structure Exter ior W*ll Horizontal Vertical 1.17+/-0.16 1.5910.1 5 Dec. 2015 120555*5VR* 28*RO DSl *OlA Discharge Structure Interio r Wall Horiiontal Vertical 0.46+/-0.09 0 .42+/-0.09 Aug. 2014 120555.SVR* 17-RO DSl*OlB Dlschorge Structute Interio r Wall llorlzontal Vertica l 0 .4310.10 0.3210.07 Aug. 2014 120555*5VR* l7*RO DSR*Ol Discharge Struct ure Exterior Slab E*W N*S 1.3210.18 0 .78+/-0.10 Dec. 2015 120555*SVR*28*RO EHRE*Ol Equ ipment Hatch Structure Exterior Slab E*W N*S 0 .72 +/-0 .15 1.22+/-0.23 Ap r. 2014 120555-SVR* ll-RO ISE*Dl Intake Structure Exterior Wall Horizontal Vertical 0.5810.09 0 .2610.07 Aug. 2014 120555*SVR* l7*RO ISER*Ol Intake Structure Exterior Slab ll*S E*W 0 .6410.13 1.29+/-0.20 Aug. 2014 120555 *SVR* l 7*RO CBMA IE*Ol Ctr I. Rm. Ma keup Air Intake Platfo rm Exterior Slab E*W N*S 1.0110.17 0.8910. 18 Dec. 201S 120555*5VR*28*RO MSBE*Ol Missile Shield for Equ ipment Hatch Exterior Wall Horizontal Vertical 0 .96+/-0.19 0.39+/-0.11 Aug. 2014 120555-SVR* l7*RO RCAT*Ol RCA Tu nnels Interior Wall Horizontal Vertic al 0.1510.04 0.6310.11 Aug. 2014 l20555-SVR*l 7*RO RCAT*02 RCA Tu nnels Interio r Wall Horii ontal Vertical 0 .73+/-0.ll 1.1210.14 Jan. 2015 12055S.SVR*23 *RO 34SBKR*Ol Switch Yard Ex*terior Slab ll*S E-W 0 .7610. 18 0.76!0.19 Aug. 2014 12055S*SVR*17-RO RAT*Ol Switch Yard Exter ior Slab tl-S E*\V 1.1310.19 0.84+/-0.16 Aug. 201 4 120555*SVR*l7*RO SF6BD*Ol Switch Yard Exterior Slab f.\V N*S 0 .8210.21 1.1010 .30 Aug. 2014 120555*SVR*l 7*RO CW202*01 Servlce/Circ. Water Pump House Interior Wall Horiionta l Vertical 0 .6310.15 1.07+/-0 .22 Jan. 2015 1205SS *SVR*23-RO SW102* 01 Service/Circ. Water Pump House Interior Wall Hor izontal Vertical 0.67!0.10 1.20+/-0. 19 Aug. 2014 12055S *SVR* l 7*RO SWE*OlN Service/Clrc. Water Pump Ho use Exterior Wall Hor izontal Vertica l 1.1810.18 0.89+/-0 . 15 Dec. 2015 1205S5*SVR*28*RO SWE*015 Service/Circ. Water Pump llouse Exter ior Wall Horizontal Ve rtical 1 .0210.23 1.0410.15 Dec. 2015 120555-SVR*28*RO WB316*02 Waste Process Building Inte rior Slab tl-5 E*W 0 .52+/-0.08 O.S4i0.10 Jan. 2015 12055S*SVR*23-RO WBE*Ol Waste Process Building Exter ior Wall Horizontal Vert ic al 0 .8010.19 0.70+/-0.10 Aug. 2014 120555*SVR* l7*RO WB5T2*02 Waste Process Building Interior Wall Ho rizontal Ver tical 1.8110.27 1.17+/-0.22 Dec. 2015 120SSS*SVR*28*RO Report No. 16026B*R*01 -A-5 of A-5* Revision O

Appendix B Independent Verification Report No. 160268-R-01 - B-1 of 8 Revision 0

REPORT INDEPENDENT VERIFICATION CHECKLIST SIMPSON GUMPERTZ & HEGER I Engineering of Struclurcs and Building Enclosures Project Number:160268 I Report No. and Revision No.:

160268-R-01, Rev. O I Report Type: Full Report Scope of Review: Review of Report and Appendices Method of Verification =Design Review (Alternate Calculations and Qualification Tests are not permitted) y N N/A l8J D D Are assumptions, opinions. judgments, and technical approaches correct?

Are assumptions used to perform the design or analysis activity adequately described and l8J D D reasonable?

Are applicable codes, standards, and regulatory requirements properly identified, and are l8J D D the ir requirements met?

l8J D D Was an appropriate design or analysis method used?

Have the supporting calculations, drawings, figures, and tables been reviewed for techn ical l8J D 0 completeness and compliance with QANF procedures?

l8J 0 D Were design inputs correctly selected and incorporated into design?* 1 l8J 0 D Are results interpreted correctly?

l8J 0 D Are resu lts, conclusions, and recommendations reasonable?

l8J 0 D Are the organization and clarity of the report adequate?

Are the necessary design inputs for interfacing organization specified in the design 0 0 l8J documents or in supporting procedures or instructions?

Were Checker(s) assigned to perform independent verification? And if so, are the Report 0 [8] D Checker Assignment and Review Sheets used, properly completed, and attached?

0 Other items

>---- for checklist.

0 if necessary,

- added by the 0 PICorPM.

Independent Verifier:

Glenn R. Bell JL-~~ 7/27/2016 Printed Name Signature Date

'Any calculations. comments, or notes generated as part of this review should be signed, dated, and attached to this checklist. Such material should be labeled and record ed In such a manner as lo be ln!ellioible to a technlcallv oualified third oartv.

Notes:

1

• Design inputs were properly selected from the referenced documents; the results presented in this report will be used in future design confirmation calculations.

Report No. 160268-R-01 - B-2 of 8 Revision O

REPORT INDEPENDENT VERIFICATION COMMENT SHEET SIMPSON GUMPERTZ & HEGER I Engineering of Sltuc lures and Building Enc losures Report Number: 160268-R-01 Independent Verifier: Glenn R. Bell Comments Resolution Section1 .4.3 - Verify the Structural Monitoring Verified . See Section 2.2 of the Seabrook SMP.

Program applies to the Containment Building.

Section 1.4.4 - Discussion of Reliability Index Revised section.

seems more appropriate than discussion on Reliability.

Section 2.2 - List parameters references to the Added ratio of mean to nominal resistance and SGH calculation from Ellingwood et al. coefficient of variation of resistance.

Section 2.3.2 - Add table of Cl grids to report. Added as Appendix A.

Add note that strains below the Zone I limit Added text in Section 1.4.3.

0.01% are negligible.

Section 3.3 - Third paragraph is confusing . Rewrote the paragraph based on comments and Review and rewrite. updated information.

Resolved by (Preparer): Michael Mudlock JllK.ki}J~

Accepted by (lndep. Verifier): _ __ G_le~n~n~R~*~B_e~ll_ __~ __ e._, -~ -~ -

Report No. 160268-R-01 - B-3 of B Revision 0

Attachment 1 External Peer eview ocumentation Note: Bruce R. Ellingwood PhD, PE, NAE, F SEl, Dist M ASCE, (College of Engineering Distinguished Professor, Department of Civil and Environmental Engineering, Colorado State University) performed a peer review of Revision B of this document (160268-R-01) , which did not address the development of ASR load factors for the reinforced concrete Interior Containment Structures. As stated in Chapter 4 of Revision O of this document, because ACI 318-71 governs the design of these structures, the discussion and conclusions provided in Chapter 2 of this document apply to Chapter 4. Since Dr. Ellingwood reviewed and accepted the conclusions of Chapter 2, we did not believe additional peer review of this document was necessary.

Report No. 160268-R-01 - Att. 1-1 of Att.1 -3

• Revision 0

Brnce R. Ellingwood, Ph.D., P.E., N.A.E.

826 Rockwood Lane Estes Park, CO 80517 Tel: (970) 586-3064 July 15, 2016 MEMORANDUM To: Simpson, Gumpertz & Heger Said Bolourchi, Ph.D., P.E., Senior Principal Re: Review of Report 160268-R-O I: Development of ASR Load Factors for Seismic Category 1 Structures at Seabrook Station, Seabrook, NH (SGH Project 160268)

Refs:

l. Simpson Gumpertz & Heger Tnc., "Computation of Load Factors for ASR Demands for Seismic Category 1 Structures Other Than Reactor Containment, SGH Document No.

160268-CA-O I, Revision B, June 2016.

2. Simpson Gumpertz & Heger Inc., "Load Factors and Load Combinations for Analysis of ASR Effects on Seabrook Station Containment Building", SGH Document No. 160268-L-O I, Revision A, July 2016.

3. Ellingwood, B.R. Review of Computation of Load Factors for ASR Demands for Seismic Category l Structures Other Than Reactor Containment, Revision I3 (SGH Project No.

160268), July 12, 2016

4. El lingwood, B.R. "Review of Load Factors and Load Combinations for Analysis of ASR Effects on Seabrook Station Containment Building, dated 9 June 2016 (SGH Project No.

160268), July 11 2016.

The subject report summarizes work performed by Simpson, Gumpertz & Heger (SGH), to develop load factors and load combinations for alkali-silica reaction (ASR) - related demands, which are intended to be incorporated into the existing load combinations defined in the Updated Final Safety Analysis Report (UFSAR) for NexlEra Energy Seabrook Station Category I Structures and Containment. The ASR load requirements for the Category I structmes arc intended to maintain the reliability indices that were inherent in the original design load combinations provided in ACJ Standard 318-71. The ASR load requirements for the Containment are intended to provide the same margin of safety as that provided in the ASME Boiler and Pressure Vessel Code, Section Ill, Division 2/ACJ Standard 359-74 (hereinafter the ASME Code). The details of the approach taken are summarized in Refs. I and 2.

- Att. J-1 of Att.1 Revision 0 Report No. 160268-R-Ol

Refs. I and 2 were reviewed independently, and the results of these reviews were communicated in Refs. 3 and 4 to SGJ-J. Subsequently, these review comments were discussed at length with SGH personnel. Refs. I - 4 are hereby incorporated by reference in this review of Report 160268-R-01. Jn my opinion, all review comments in Refs. 3 and 4 have been addressed by SGH satisfactorily, and no issues raised in these reviews remain to be resolved .

ln my opinion, the methods employed in Report 160268-R-OI for revising the load combinations in the lJFSAR for the Seabrook Station for ASR demands on Category I struclmes are, in general, consistent with the state of the art of structural reliability assessment and the development of probability-based load and resistance factors for structural design. furthermore, the methods employed for revising the load combinations for the Containment, while not based on principles of strnctural reliability, are entirely consistent with the conservative deterministic approach to safety assurance historically taken in developing the ASME Code.

Sincerely, Bruce R. Ellingwood, Ph.D., P.E., N.A.E.

- Att . 1- 1 of Atl.l Revision 0 Report No. 160268-R-OI L