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NYS000546 - Slides, Nrc/Epri Steam Generator Task Force Meeting (February 12, 2015)
	ML15160A414
Person / Time
Site:	Indian Point
Issue date:	02/12/2015
From:	; State of NY, Office of the Attorney General
To:	; Atomic Safety and Licensing Board Panel
	SECY RAS
References
	RAS 27915, ASLBP 07-858-03-LR-BD01, 50-247-LR, 50-286-LR
	Download: ML15160A414 (59)
	v • d • e

NYS000546 Submitted: June 9, 2015 NRC / EPRI Steam Generator Task Force Meeting February 12, 2015

Agenda 8:30 am Introductions NRC and Industry Opening Remarks NRC and Industry EPRI SGMP Steam Generator Task Force Update (Industry)

Open Technical Issues

Noise Monitoring

General Discussion Items

San Onofre Lessons Learned

Tubesheet Joint Design

Steam Generator Requirements in ASME Code

Auto Analysis Workshop

Thermal Heat Treatment of Tubing

Action Levels for Leakage

Status of Adopting TSTF-510 2

Agenda

General Discussion Items (continued)

Consistent Measuring of Flaw Amplitude

Basis for Section D3.1 of In Situ Pressure Test Guidelines

Anti-vibration Bar Position Verification 10:00 am Break 10:20 am Standing Discussion Topics (Industry)

Summary of Recently Issued SGMP Technical Reports

Status of Industry Guidelines

Interim Guidance

NEI 03-08 Deviations

Recent Steam Generator Operating Experience

Feedwater Support - Generic Implications 11:20 am NRC Discussion / Items of Interest (NRC)

Issues Discussed in Past (Monitoring)

Tube-to-Tubesheet Weld and Divider Plate Cracking Report 11:45 am Address Public Questions/Comments (NRC) 12:00 pm Adjourn 3

Open Technical Issues - SGTF Noise Monitoring

- Recommendations have been provided to the Examination Guidelines Revision 8 Committee and the Integrity Assessment Revision 4 Committee

New appendix has been drafted for the Examination Guidelines for noise monitoring

Final drafts for industry review scheduled mid 2015 4

General Discussion Items 5

San Onofre Lessons Learned 6

Investigation into the Onset of In Plane Fluid Elastic Instability SGMP funding has been approved for 2015 - 2017 to investigate the onset of in plane fluid elastic instability A series of tests have been proposed by Canadian Nuclear Labs

- Air Flow tests Develop a basic understanding of in plane vibration

- Two-Phase Freon Tests Use three support configurations and the most relevant two-phase flow conditions, demonstrate in-plane fluid elastic instability 7

Phase 1 Test Setup - 2015 Meeting among industry experts to determine tube bundle and/or support configuration(s) and flow conditions Complete test section assembly and calibration 8

Phase 2 Air Flow Tests - 2015-2016 Observe in plane vibration and fluid elastic instability behavior in air flow to make preparations for testing in two-phase Freon flow Examine a variety of support configurations Tests will be representative of very high void fractions where the supports could be made wet or dry Approximately 24 configurations could be tested Different number of U-bend support locations Different tube-support designs Wet and dry supports Centered and preloaded supports A specific test matrix will be developed after the first industry expert meeting 9

Phase 3 Two-Phase Freon Tests - 2016-2017 Convert the test rig for use with Freon Develop test plans and procedures Test at least three support configurations in a two-phase flow condition most relevant to the industry Measure tube damping with flow Measure vibration at 0 to 98% void fraction up to and slightly beyond critical flows 10

Application of Test Results Prediction of the final solution is difficult (new Connors constant, more effective supports, etc.)

Goal is to understand what leads to the onset of in-plane fluid elastic instability

- Utilities may be able to use results to avoid operating in these regimes

- SG designers may be able to understand their margins in operating SGs and avoid it with new designs This is a learning effort that will be adjusted or stopped as each phase is completed, depending on the results Tritons FIV code can be updated to include information from the results of this research 11

Tubesheet Joint Design 12

Tubesheet Joint Design The NRC learned that the tube-to-tubesheet joint at one plant with replacement steam generators (alloy 690 tubing) was designed as the pressure boundary instead of the tube-to-tubesheet weld.

NRC requested the SGMP to determine if other steam generators have this design Based on an SGMP survey provided to the NRC in December 2014, there are 5 other domestic units identified designed and fabricated by the same vendor

- The tube-to-tubesheet welds were designed to meet ASME Section III requirements 13

ASME Code Section III Requirements for Tube-to-Tubesheet Welds Credited as Pressure Boundary In addition, for those plants that consider the tube-to-tubesheet weld as the pressure boundary, a difference exists in the practices of the vendors regarding whether or not the welds are analyzed in accordance with NB-3000

- If the tube-to-tubesheet weld satisfies the requirements currently specified in NB-4350, all the ASME design requirements for tube-to-tubesheet welds in a Class 1 component have been satisfied An inquiry was sent to Section III Code Committee for the January 28th inquiry meeting

- Chair of the Interpretations committee will circulate the question to the entire BPV III standards committee on a letter ballot

- Some committee members stated that it was never intended to require full stress analysis of a tube to tubesheet weld and that NB-4350 was intended as a design rule

- A working group has been given the responsibility to resolve the issue

- The results of the inquiry may be a Code revision 14

SG Requirements in ASME Section XI 15

Steam Generator Requirements in ASME Code NRC Observations from recent meetings

- Section XI has rules that go beyond what is covered by the plant Technical Specifications

- If ASME deletes all the SG requirements from the ASME Code, the NRC will assess whether 10 CFR 50.55a should be modified to incorporate similar requirements

- NRC preference is to use consensus codes and standards; however, if there are no consensus codes and standards, the NRC may develop its own requirements NRC encouraged the SG industry to evaluate the situation, engage the ASME Code, and discuss in a future meeting 16

Steam Generator Requirements in ASME Code ASME Code action to delete steam generator requirements from Section XI did not pass

- 4 negative votes out of 43 Working on putting the preservice requirements in Section III Changes to personnel qualification Section XI, IWA-2300 passed Working Group Personnel Qualification, Surface, Visual, Eddy Current and Subgroup NDE at the January Code meeting All other requirements should be deleted The next opportunity to make change is the 2017 Code 17

Auto Analysis Workshop 18

Steam Generator Auto Data Analysis Workshop At the August 2014 NRC meeting with the SGTF, the NRC requested that the industry hold a workshop on SG automated data analysis The purpose of the meeting would be to :

- Discuss industrys response to previous NRC feedback on auto data analysis

- Discuss Industry guidance

- Provide info on current auto data analysis systems

- Discuss auto analysis operating experience

- Provide an opportunity to ask questions of industry auto data analysis experts The previous EPRI Auto Analysis Workshop was in Feb 2011

- The 54 registrants included: NRC (12), Utilities (14), NDE Vendors (20),

Researchers (2) and EPRI (6) 19

Steam Generator Auto Data Analysis Workshop 2015 Auto Data Analysis Workshop Location:

- EPRI Charlotte Schedule:

- Follows Aug 19 (AM) NRC meeting with SGTF

- Workshop Day 1 - Aug 19: 1:00 PM - 5:30 PM

- Workshop Day 2 - Aug 20: 8:00 AM - 4:30 PM

- Planned Participants Utilities SG NDE Vendors NRC Research organizations 20

Steam Generator Auto Data Analysis Workshop Proposed 2015 Auto Data Analysis Workshop Format

- Session 1 - Industry Perspective

- Session 2 - Technology

- Session 3 - Operating Experience

- Session 4 - Panel Discussion

- Session 5 - Technology Demonstrations 21

Thermal Heat Treatment of Tubing 22

Thermal Heat Treatment of Tubing Material NRC Question

- Guidelines have a temperature range specified with uncertainty bands (716 degrees C, -0, +22)

- Does this range consider measurement uncertainty?

- Should guidelines be revised to be clearer?

Measurement uncertainty is not explicitly addressed within the specification requirements or their technical basis in SGMP Technical Report 3002003124

- Section 3.3.6.2 describes the technical basis for the thermal treatment temperature 23

Thermal Heat Treatment of Tubing Material Thermal treatment requirements were developed for Alloy 600 to:

- Enhance carbide decoration of grain boundaries for SCC resistance

- Allow Cr to diffuse back to grain boundaries (reduces possible sensitization associated with Cr-depletion at grain boundaries)

- Reduce residual stress from straightening and surface grinding.

None of these objectives are strongly influenced by temperature variations in the range of 716°C to 738°C.

Thermocouple instrument error is insignificant relative to temperatures for carbide precipitation and stress relief.

In the 1999 revision of the specification, the thermal treatment time was increased to add additional conservatism 24

Thermal Heat Treatment of Tubing Material Most significant source of uncertainty is the temperature variation within the furnace:

- Tubing is produced in accordance with ASME III NB-2000, which requires calibrated and temperature-surveyed furnaces

- Hottest and coldest temperatures in the furnace are recorded to ensure compliance.

Specification ensures that thermal treatment objectives are met through metallurgical analysis and stress measurements.

Specification guidance is sufficient and does not require revision 25

Action Levels for Leakage 26

Primary-to-Secondary Leakage Limits NRC Question

- Action Levels are based on 150 gallon per day limit

- Is there any guidance to utilities if leakage limit in Technical Specification is less than 150 gallons per day?

Guidelines require station procedures to contain limits and actions as required by Technical Specifications

- Guidelines note that, in most facilities, the alarm set points are determined by the plant Technical Specifications (actions to adjust set point ensure that the new set point is within Tech Spec limits) 27

Status of Adopting TSTF-510 28

Status of Adopting TSTF-510 Majority of the US Utilities will have TSTF-510 submittals to the staff by the end of 2015 Three units (3 plants) economic evaluation does not support submittals at this time 29

Consistent Measuring of Flaw Amplitude 30

Feb 2013 SGTF Meeting with NRC The NRC staff inquired about the industry guidance on evaluating signal amplitude, and phase during eddy current testing when substantial noise is present.

The NRC also asked if there was industry guidance to ensure a method for consistently quantifying flaw signal amplitude changes and phase changes in the presence of tube noise.

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Example of Amplitude Comparison 32

Example of Amplitude Comparison 33

EPRI SG Examination Guidelines Present Guidance - Revision 7

- When historical reviews are performed to determine if supplemental testing is warranted, the licensee shall define what constitutes change in terms of voltage and/or phase angle from the Lissajous signal in the current inspection as compared to the same Lissajous signal in the first ISI or the first ISI recorded on optical disk.

- When cracking mechanisms are present, the process of historical review is reviewing the actual raw or processed eddy current data; review of database report entries is not acceptable. When cracking mechanisms are not present, a review of the database report entries is acceptable.

Revision 8 committee is considering additional guidance 34

Basis for Section D3.1 of In Situ Pressure Test Guidelines 35

Basis for Section D3.1 of In Situ Pressure Test Guidelines Note in Section D3.1 of In Situ Pressure Test Guidelines:

Degradation at lattice type eggcrate supports is not exempt from in situ proof testing, as it has been shown that these supports provide little strengthening to regions with axial degradation. The same is true of broached TSP supports.

Basis for this note was testing performed in the 1990s on axial flaws within eggcrate supports, not documented in the guidelines Tests have recently been performed to provide basis for trefoil and quatrefoil supports and will continue to address eggcrates 36

Results of Recent Testing 37

Conclusions For wear flaws that challenge 3dP structural integrity performance criterion, trefoil supports do not elevate the burst pressure Similar results are expected for quatrefoil and eggcrate supports 38

Anti-Vibration Bar Position Verification 39

Anti-Vibration Bar Mispositioning White paper developed incorporating information from 2012 meeting among SG vendors regarding AVB position verification

- Available to utilities on EPRI website Recommendations have been provided to the Integrity Assessment Guidelines Committee Westinghouse published NSAL 12-7, Insufficient Insertion of Anti Vibration Bars in Alloy 600TT Steam Generators with Quatrefoil Tube Support Plates

- Concluded that it is judged that the worst case consequence of this issue does not result in a Substantial Safety Hazard SGMP Project began project in 2012 to provide generic input for plant-specific U-bend tube fatigue analysis Follow up survey in 2012 indicates the utilities are familiar with the issue and are taking actions as appropriate 40

Anti-Vibration Bar Mispositioning The issue is considered applicable only to those steam generator manufactured before 1985

- AVB design has reduced or eliminated gaps as much as possible by controlling AVB and tube tolerances.

- Manufacturing process control has been improved to document the as-built condition vs. the as-designed condition.

- AVB depth of insertion and alignment are recorded in manufacturing records.

- Significant depths of insertion variations are not expected; hence, the potential for flow peaking factors is minimal.

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SGMP U-Bend Fatigue Project SGMP began a project in 2012 to perform the generic work that would provide necessary inputs into plant-specific analyses

- ATHOS analysis provides input to flow induced vibration analysis for open and occluded TSP conditions

- Mean stress and unit bending moment calculations for Fixed, Pinned and Open Gap tube constraints

- Review of flow peaking factor data from the NRC Bulletin 88-02 analyses to determine a correction factors for application to affected models of SG (F, D5, 44F, 51F)

- FIV analysis for rows of interest (F: 5-12) for Fixed, Pinned and Open Gap tube constraints and case-specific damping 42

SGMP U-Bend Fatigue Project Model F work completed in 2013 (Report No. 3002001991)

Model D5 technical work was completed in 2014

- Technical report will be published in 2015 Model 44F and 51F work will begin in 2015

- Technical report will be published in 2016 Plants with susceptible SGs are investigating the insertion depths of AVBs

- They need to generic work to be completed prior to the site specific analysis 43

Standing Discussion Topics 44

Recently Issued SGMP Technical Reports Steam Generator Management Program: Investigation of Crack Initiation and Propagation in the Steam Generator Channel Head Assembly

- SGMP Technical Report 3002002850 (October 2014)

Steam Generator Management Program: Lead Stress Corrosion Cracking of Nuclear Grade Alloy 800

- SGMP Technical Report 3002002853 (Nov 2014) 45

SGMP Industry Document Status and Revision Schedule Guideline Title Current Report # Last Imple- Interim Review Comments Rev # Pub mentation Guidance Date Date Date(s)

SG Integrity 3 1019038 Nov 9/1/10 SGMP-IG- TBD Rev 4 in Assessment 2009 10-01 progress Guidelines SGMP-IG-12-01 EPRI SG In Situ 4 1025132 Oct 10/10/13 None TBD Rev 5 will Pressure Test 2012 begin in 2015 Guidelines PWR SG 7 1013706 Oct 9/1/08 SGMP-IG- TBD Rev 8 in Examination 2007 08-04 progress Guidelines SGMP-IG-12-01 SGMP-IG-14-02 PWR SG Primary- 4 1022832 Sept. 4/11/2012 None 2015 to-Secondary 2011 7/11/2012 Leakage 46 Guidelines © 2015 Electric Power Research Institute, Inc. All rights reserved.

SGMP Industry Document Status and Revision Schedule Guideline Title Current Report # Last Pub Imple- Interim Review Comments Rev # Date mentation Guidance Date Date(s)

PWR Primary Water 7 3002000505 April 1/28/2015 None 2017 Chemistry 2014 Guidelines PWR Secondary 7 1016555 Feb 2009 8/20/09 SGMP-IG- TBD Rev 8 process Water Chemistry 11/20/09 13-01 planned to Guidelines SGMP-IG- begin in 2015 14-01 Steam Generator 3 1022343 Dec 2010 9/1/11 None N/A Rev 4 in Management 12/31/11 progress Program Administrative Procedures Steam Generator 1 1019037 Dec 2009 N/A None N/A Rev 2 in Degradation Specific progress Flaw Handbook 47

Interim Guidance SGMP-IG-14 Examination Guidelines, R7 Prescriptive guidance not consistent with current performance-based requirements in Technical Specifications were removed from Section 3 of the Examination Guidelines Plants operational assessment dictates operating intervals for each degradation mechanism within the confines of Technical Specification intervals Example: A plant may be required to inspect 100% of the top of the tubesheet for cracking, but not 100% of the tubing for wear 48

Interim Guidance SGMP-IG-14 Examination Guidelines, R7 Sampling shall be performed such that all tubing is examined within the periods established by Plant Technical Specifications and the Degradation Assessment.

Wording removed:

Tube selection within a sample plan shall be governed by the following requirements:

1. The tubes are selected on a random or systematic basis, and evenly distributed across the tube bundle to the extent practical (e.g. As Low As Reasonably Achievable (ALARA) considerations).

2. All inservice tubes that have prior indications of degradation and/or historical possible loose parts (PLP) are examined through the area of interest when the applicable SGs are open for examination.

3. Peripheral tubes, including tubes adjacent to no-tube lane regions, are included or added to a sample plan or considered a separate sample plan when there is reason to expect that loose parts are present or were introduced into the SG secondary side. A secondary-side foreign object search and retrieval (FOSAR) examination may be used to meet this 49 requirement.

Interim Guidance SGMP-IG-14 Examination Guidelines, R7 Section 3.6 contains a reference to the Steam Generator Integrity Assessment Guidelines for determining steam generator examination scope Section 6 of the Integrity Assessment Guidelines requires utilities to develop a Degradation Assessment which includes an inspection scope for all existing and potential degradation mechanisms 50

NEI 03-08 Deviations

Three long-term deviations

- Two Steam Generator Examination Guidelines, R7

- Single party auto analysis

- Steam Generator Integrity Assessment Guidelines, R3

- Use of site-specific sizing indices

One short term deviations

- Steam Generator Examination Guidelines, R7

- PSI prior to hydro 51

Operating Experience 52

Recent Operating Experience Reported at December SGMP Technical Advisory Group Meeting

Spring 2014 outage inspections identified foreign objects laying on the debris screens for both the A and B steam generators.

These foreign objects were determined to be part of the support system for the feedrings.

Additional inspections identified that the feedring supports had been damaged due to a steam void in the feedring system.

The damaged supports were repaired during the outage.

The function of the feedring was not impacted.

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Recent Operating Experience Reported at December SGMP Technical Advisory Group Meeting

The cause evaluation included a review of the guidance provided in NUREG-0291 and NUREG-0927

Potential causes for the steam void:

Feedring leakage through inspection port bolted to ends of feedring

Back leakage through the feedwater system

An important mitigating action is to limit the feed rate while the feedring is uncovered; industry accepted limit is 150 gpm

Follow-up inspections will be implemented to verify effectiveness of actions taken

This experience was reported at TAG meeting June 2014 54

NRC Discussions/Items of Interest 55

Acronyms 56

Acronyms

ASME - American Society of Mechanical Engineers

EPRI - Electric Power Research Institute

AVB - Anti Vibration Bar

IG - Interim Guidance

N/A - Not Applicable

NEI - Nuclear Energy Institute

NRC - Nuclear Regulatory Commission

PSI - Preservice Inspection

PWR - Pressurized Water Reactor

SG - Steam Generator 57

Acronyms

SGMP - Steam Generator Management Program

SGTF - Steam Generator Task Force

TBD - To Be Determined

TSP - Tube Support Plate

TT - Thermally Treated

US - United States 58

TogetherShaping the Future of Electricity

ML15160A414

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