ML17283A041

Enclosure 3 - Licensees Presentation-Seabrook Station, License Amendment Request 16-03 ASR Structural Evaluation Methodology

ML17283A041
Person / Time
Site:	Seabrook
Issue date:	08/24/2017
From:	Browne K, Collins M Nextera Energy
To:	Office of Nuclear Reactor Regulation
Poole J, NRR/DORL/LPLI, 415-2048
Shared Package
ML17283A039	List: ML17278A748 ML17283A040 ML17283A041
References
CAC MF8260, EPID L-2016-LLA-0007
Download: ML17283A041 (13)

Text

Seabrook Station License Amendment Request 16-03 ASR Structural Evaluation Methodology Ken Browne, Mike Collins 24 August 2017

2 NextEra Energys nuclear fleet is 4th largest in MW generation and number of reactors in the U.S.

Turkey Point (Florida) 1,600 MWe Turkey Point (Florida) 1,600 MWe NextEra Energys nuclear plants represent approximately 27 percent of our generation Acquired: 2007 Point Beach (Wisconsin) 1,193 MWe Acquired: 2007 Point Beach (Wisconsin) 1,193 MWe St. Lucie (Florida) 2,000 MWe St. Lucie (Florida) 2,000 MWe Acquired: 2002 Seabrook (New Hampshire) 1,245 MWe Acquired: 2002 Seabrook (New Hampshire) 1,245 MWe Acquired: 2006 Duane Arnold (Iowa) 615MWe Acquired: 2006 Duane Arnold (Iowa) 615MWe

3 The foundation for everything we do are the Values and Core Principles of our Nuclear Excellence Model

4 Objective Understand staff expectations for methodology Address comments on LAR Stage 3 methodology Discuss methodology document Show consistency of applied methodology Schedule & path forward

5 Overview of ASR Evaluation Process License Amendment Request Methodology Document Structural Analysis &

Evaluation Threshold Limits Stage 1, 2, and 3 analyses Material properties Repeatable process for stage 1, 2, and 3 Decision points for analysis Demand calculations Compliant to ACI 318-71, ASME and UFSAR acceptance criteria Establish design margin Structures Monitoring Program Threshold limits ASR expansion limits Administrative limits

6 Overview of Methodology Document Overview Codes and Standards Materials Load and load combinations Analysis

- Stage One and Stage Two

- Stage Three Correlation of model to field conditions Decision points Acceptance Criteria ASR Threshold Limits and Monitoring

7 FEA Model Field observations &

measurements Distress &

Deformation Sustained Loads Cracking Is cracking observed?

Is cracking limit exceeded?

Concrete Backfill Pressure Is backfill confined?

Is there softening in the confinement?

Is scaling needed to match field condition?

Moment Redistribution Is there a self-relieving condition?

Is there a localized moment exceedance?

Does structural configuration conform to ACI 318-71 Section 8.6?

Flexural cracking limited to ACI 318-71 Axial tension and shear cracking stiffness limits Limit to overburden pressure Limit to strength of confinement Limit to field observations Limit to ACI 318-71 8.6 for conforming structures Confirm with alternative analysis Factored Loads Demand-to-capacity ratio Acceptance Criteria Limits of use Decisions Evaluation Stage Three Evaluation Process

8 Consistency of Methodology CEB Make-up Air Intake RHR FSB Control & Diesel Mech. Pen. & MSFW-W Cooling Tower Electrical Manholes Condensate Storage Tank Equipment Hatch Containment Steam Gen. Blowdown CEVA Electrical Tunnel Containment Internals Stage 3

3 3

3 3

3 3

3,2,1 2

1 1

1 1

1 1

LOADS AND LOAD COMBINATIONS Load Combinations

Containment NA NA NA NA NA NA NA NA NA NA

NA NA NA NA Containment Internal Structures NA NA NA NA NA NA NA NA NA NA NA NA NA NA

Other Seismic Category I Structures

NA

NA ANALYSIS Selection of Starting Stage

Stage One Analyses NA NA NA NA NA NA NA

NA

Stage Two Analyses NA NA NA NA NA NA NA

NA NA NA NA NA NA Stage Three Analyses

NA NA NA NA NA NA NA Field Observations to Support Stage Three Analyses

NA NA NA NA NA NA NA Non-ASR Demands for Stage Three Analyses

NA NA NA NA NA NA NA ASR Demands for Stage Three Analyses

NA NA NA NA NA NA NA ASR Expansion of Structural Components

NA NA NA NA NA NA NA ASR Expansion of Concrete Backfill

NA

NA NA NA NA NA NA NA NA NA Correlation of Model with Field Conditions

NA NA NA NA NA NA NA Refined Analytical Methods

NA NA NA NA NA NA NA Use of Cracked Section Properties in Stage Three Analyses NR

NA NA NA NA NA NA NA Use of Moment Redistribution in Stage Three Analyses

NR NR NR NR NR NA NA NA NA NA NA NA Factored Load Calculation

NA NA NA NA NA NA NA ACCEPTANCE CRITERIA Acceptance Criteria for Containment NA NA NA NA NA NA NA NA NA NA

NA NA NA NA Acceptance Criteria for Other Seismic Category 1 Structures

NA

Impact of ASR on Code of Record Acceptance Criteria

Acceptance Criteria for Isolation Gaps

NA

NA NA NA

NA Acceptance Criteria for Foundations

NA Acceptance Criteria for Stability

NA ASR THRESHOLD LIMITS AND MONITORING Methodology to Account for Potential Future ASR Expansion

ASR Threshold Limits and Monitoring for Stage One Structures NA NA NA NA NA NA NA NA NA 1.5 1.8 3.5 3.0 3.0

ASR Threshold Limits and Monitoring for Stage Two Structures NA NA NA NA NA NA NA NA 1.6 NA NA NA NA NA NA ASR Threshold Limits and Monitoring for Stage Three Structures 1.2 1.4 1.2

NA NA NA NA NA NA NA

9 Threshold Monitoring Perform monitoring.

Is threshold limit approached?

Methodology Yes No Structural Evaluation Identify minimum threshold factor Consider Structural Modification Further analysis Re-evaluate using same methodology, Identify new threshold factor Continue Monitoring Yes

10 Building Deformation Analyses (1 of 2)

Structure Schedule Percent Complete Condensate water storage tank Complete 100%

Containment enclosure building Complete 100%

Containment enclosure ventilation area Complete 100%

Containment structure Complete 100%

Equipment hatch missile shield Complete 100%

Steam generator recovery blowdown bldg.

Complete 100%

Control room make-up air intake Complete 100%

Electrical cable tunnels Complete 100%

Pre-action valve building 3Q2017 80%

RHR equipment vault Complete 100%

Containment internal structures 3Q2017 80%

Main steam and feed water east pipe chase 3Q2017 50%

Hydrogen recombiner structure Safety-related electrical duct banks and manholes 1Q2018 40%

Emergency feedwater pump building 3Q2017 10%

Fuel storage building 3Q2017 60%

Structures that are/expected to be Stage 3

11 Building Deformation Analyses (2 of 2)

Structure Schedule Percent Complete Control Building Diesel Generator Building 4Q2017 10%

Mechanical Penetration Personnel hatch area Main steam and feed water west pipe chase 4Q2017 30%

Primary auxiliary building 4Q2017 10%

Service water cooling tower incl. switchgear rooms 1Q2018 Service water access (inspection) vault 1Q2018 Circulating water pumphouse (below el. 21')

Service water pumphouse 2Q2018 Piping (RCA) Tunnels 2Q2018 Tank farm area 2Q2018 Waste processing building 2Q2018 Structures that are/expected to be Stage 3

12 Discussion with NRC Staff

13 Wrap Up The importance to establish a repeatable methodology with limits is understood A consistent methodology is being applied in the structural evaluations A methodology document will be submitted Next Steps Submit methodology document Respond to issued RAIs Maintain communications with NRC staff