ML17283A041

Enclosure 3 - Licensee'S 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

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

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

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

Objective

• Understand staff expectations for methodology

• Address comments on LAR Stage 3 methodology

• Discuss methodology document

• Show consistency of applied methodology

• Schedule & path forward 4

Overview of ASR Evaluation Process

• Stage 1, 2, and 3 analyses License Amendment Request

• Material properties

• Repeatable process for stage Methodology Document 1, 2, and 3

• Decision points for analysis

• Demand calculations Structural Analysis &

• Compliant to ACI 318-71, Evaluation ASME and UFSAR acceptance criteria

• Establish design margin Threshold Limits Structures Monitoring

• Threshold limits Program

• ASR expansion limits

• Administrative limits 5

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 6

Stage Three Evaluation Process Sustained Field observations &

measurements FEA Model Distress &

Deformation Loads Cracking Concrete Backfill Pressure Moment Redistribution Decisions

• Is cracking observed?

• Is backfill confined?

Factored Loads

• Is there a self-relieving

• Is there softening in the condition?

• Is cracking limit confinement?

• Is there a localized exceeded?

• Is scaling needed to moment exceedance?

match field condition?

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

Limits of use

• Flexural cracking limited

• Limit to overburden

• Limit to ACI 318-71 8.6 to ACI 318-71 pressure for conforming structures

• Axial tension and shear

• Limit to strength of

• Confirm with alternative cracking stiffness limits confinement analysis

• Limit to field observations Evaluation Demand-to-capacity Acceptance Criteria ratio 7

rol &D ies e Me ch. Pen l Co o .& MS Consistency of ling Tow FW -W E lect ric er al M Ma Co n den an h oles sate ke-Equ ipm Sto r ag eT Methodology en t an k up Co n tain H a tc h me nt A ir Ste am Ge CE n. B low In ta VA RH d ow n E lect ric R ke al T u nn Co n Co n CE FS B tain me el B t nt I nte r nals 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 8

Threshold Monitoring Methodology Structural Evaluation Identify minimum threshold factor Yes Perform monitoring. Yes Consider Structural Further analysis Is threshold limit Modification approached?

No Continue Monitoring Re-evaluate using same methodology, Identify new threshold factor 9

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 10

Building Deformation Analyses (2 of 2)

Structure Schedule Percent Complete Control Building 4Q2017 10%

Diesel Generator Building Mechanical Penetration Personnel hatch area 4Q2017 30%

Main steam and feed water west pipe chase 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')

2Q2018 Service water pumphouse Piping (RCA) Tunnels 2Q2018 Tank farm area 2Q2018 Waste processing building 2Q2018 Structures that are/expected to be Stage 3 11

Discussion with NRC Staff 12

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 13