ML12339A736
| ML12339A736 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 02/18/2011 |
| From: | Nuclear Energy Institute |
| To: | Atomic Safety and Licensing Board Panel |
| SECY RAS | |
| References | |
| RAS 22624, 50-247-LR, 50-286-LR, ASLBP 07-858-03-LR-BD01 | |
| Download: ML12339A736 (57) | |
Text
United States Nuclear Regulatory Commission Official Hearing Exhibit NYS000390 Entergy Nuclear Operations, Inc. Submitted: June 19, 2012 In the Matter of:
(Indian Point Nuclear Generating Units 2 and 3)
ASLBP #: 07-858-03-LR-BD01 Docket #: 05000247 l 05000286 Exhibit #: NYS000390-00-BD01 Identified: 10/15/2012 Admitted: 10/15/2012 Withdrawn:
Rejected: Stricken:
Other:
NEI Steam Generator Task Force NRC/Industry Update February 18, 2011
Agenda 8:30 am Introductions - NRC Opening Remarks - NRC and Industry NEI Steam Generator Task Force Update - Industry
- 1. NEI 97-06 Revision Status
- 2. TSTF-510 Update
- 3. EDF Divider Plate Cracking Update 4 License Renewal Issues 4.
- 5. Pre-Service Inspection Code Change
- 6. Auto-Analysis Workshop Summary
- 7. U-Bend Axial Outside Diameter Stress Corrosion Cracking Inspection Technique Peer Review
- 8. Upcoming Changes to Industry Documents 2
Agenda (Continued)
- 9. Steam Generator Operating Experience
- 10. Implementation of Noise Monitoring Techniques 11:00 am Address Public Questions/Comments 11:30 pm Lunch 1:00 pm NEI Steam Generator Task Force Update (continued) - Industry
- 11. Follow-up on Previous Meetings
- 12. Future Topics 3:30 pm NRC feedback on various issues - NRC and Industry 3:45 pm Address Public Questions/Comments - NRC and Industry 4:00 pm Adjourn 3
NEI 97-06 Revision Status Jim Riley, NEI 4
NEI 97-06 Revision Status Revision 2 issued in 2005 Need to capture changes in guidance and knowledge SGTF subgroup established Revision 3 distributed to TAG and NRC for review in November Final version of revision 3 completed in January 2011 5
NEI 97-06 Revision Status Industry comments addressed NRC comments
Consistency of shall and should statements
- Changed shoulds to statements of fact
Sending Interim Guidance letters and Review Board Interpretations to the NRC
- OK
Comments to establish consistency with technical specifications
- Definition of condition monitoring
- Change Expected to Potential tube degradation 6
NEI 97-06 Revision Status Main changes
- Reduces needed (shall) statements in recognition of EPRI guideline contents
- Uses statements of fact
- Changes Mandatory statements
- Lists required program elements
- Removes requirement to adopt performance criteria since they are in tech specs
- Updates definitions (consistent with guidelines)
- Corrects inconsistencies with tech specs and EPRI guidelines 7
NEI 97-06 Revision Status SGTF and SGMP IC endorsed the revision
- Suggested implementation
- September 1, 2011 or
- December 31 31, 2011 if plant has a spring 2011 outage PMMP approval requested
- Expected PMMP approval in March, 2011 8
TSTF-510 Update Jay Smith, Exelon 9
TSTF-510 Update Major Milestones Completed
- Rev. 0 of the Traveler & Fee Waiver Request transmitted to NRC on 3/26/09
- Fee Waiver Request Approved on 7/20/09 (ML092010534)
- 8 RAIs received via email M. Honcharik (NRC) to B. Mann (TSTF), "TSTF-510 RAIs," February 4, 2010.
- RAI Response and Rev. 1 submittal to NRC June 2010
- 3 comments received at SGTF Mtg August 12, 2010
- Response and Rev. 2 submittal to NRC October 11, 2010 10
TSTF-510 Update Remaining Milestones TSTF-510 Revision to Steam Generator Program Inspection Frequencies and Tube Sample Selection Original Current Milestone Action Target Date Target Date Responsible Group Comments/Status Submit Rev. 0 TSTF Traveler to NRC 1/1/2009 3/26/2009 TSTF/NEI SGTF Complete Receive NRC Acceptance & Schedule Letter 3/1/2009 12/31/2009 TSTF /NEI SGTF Not Sent Receive Rev. 0 RAIs (email used) 6/1/2009 2/4/2010 TSTF /NEI SGTF Complete Respond to Rev. 0 RAIs 9/1/2009 6/15/2010 TSTF /NEI SGTF Complete Submit Rev.
Rev 1 TSTF Traveler to NRC 1/1/2010 6/17/2010 TSTF /NEI SGTF Complete Receive Rev. 1 RAIs (SGTF Mtg) N/A 8/12/2010 TSTF /NEI SGTF Complete Respond to Rev. 1 RAIs N/A 9/15/2010 TSTF /NEI SGTF Complete Submit Rev. 2 TSTF Traveler to NRC N/A 9/22/2010 TSTF /NEI SGTF Complete Receive Notice for Comment 12/1/2009 4/15/2011* TSTF /NEI SGTF Current Estimate Respond to Notice for Comment 1/1/2010 5/15/2011* TSTF /NEI SGTF Current Estimate NRC Publish Notice of Availability 4/1/2010 8/31/2011* NRC Current Estimate
- Change since previous SGTF meeting 11
NRC Feedback on TSTF-510 12
EdF Divider Plate Cracking Update Helen Cothron, EPRI 13
EdF Divider Plate Cracking Update Only 900 MW plants have experienced divider plate cracking
- All have 34mm (1.33) divider plates All 900 MW units have been inspected at least one time
- 4 have had consecutive inspections
- First three divider plate inspections were conducted using PT for detection and non-qualified UT for sizing
- No change in number of cracks cracks, few variations in depth
(~1mm of growth), but this could be NDE uncertainty
- 2010 was the first use of qualified UT by Westinghouse
- With qualified techniques, cracks that were sized as 7 to 8mm in depth were sized as <2mm deep
- All indications are in or close to the heat affected zone (HAZ) of the tubesheet to stub runner weld and in or close to the HAZ of the stub runner to divider plate weld
- No cracking in the welds
- Only small (depth - 2 microns) cracks in stub runner itself.
14
EdF Divider Plate Cracking Update EdF removed 2 divider plate samples from retired SGs at Chinon B1 in 2008
- NDE prior to and following removal have same results
- UT detection by Westinghouse was the same but the indicated depth was smaller at <2mm (1.8 mm after destructive measurement)
- Stub runner discovered to be bowed in center
- HAZ had carbide dissolution in about 2mm thick layer
- EdF believes the deformation could have been caused by the first hydrostatic pressure test performed at 1.33 times design pressure (22.8 MPa or 3300 psi).
- U.S. ASME Section III hydros performed at 1.25 times design Pressure (~3100 psi) 15
EdF Divider Plate Cracking Update Triple Point
- Fabrication defects Tubesheet
- No see Divider Plate 16
EdF Divider Plate Cracking Update
- Deeper cracks are on the top and bottom of the stub runner
- Cracks are intergranular
- Propagation is parallel to the weld
- No cracks on the divider plate and no cracks on the weld
- No cracks at the triple point or near the tubesheet 17
EdF Divider Plate Cracking Update Root Cause
- SCC observed in hot leg on SGs with operating time >120,000 hrs (13.7 yrs)
- SCC observed in SG Divider Plate components where material was supplied by one vendor
- Material had high carbide level (>0.5%) and high temperature final heat treatment promoting intra carbides
- SCC observed in SGs with 34mm (1.33) thick divider plates from 3 loop plants, containing stub runners with low mechanical properties and divider plates with high mechanical properties.
- Important difference in yield strength in stub runner and divider plate. When stub runner has low mechanical properties than divider plate, then it deforms and becomes susceptible to cracking.
18
EdF Divider Plate Cracking Update Mechanical tests performed on materials with representative mechanical properties shows:
- Crack depth propagation in the center of the stub runner is from 0.07 mm/cycle (8,000 hrs) to 0.2 mm/cycle.
- Crack depth propagation in the HAZ is 0.17 mm to 0.21 mm/cycle.
19
EdF Divider Plate Cracking Update Comparison of EdF Affected Plants to US Plants Apparent Causal Factor of EdF Plants with U. S. Plants DP Component SCC Divider Plate SCC Divider Plate Thickness 1.33 Model 51: 1.31 (Nominal) Model 44F: 1.50 Models 51F/51M/
54F/D3*/D5/F: 2.0 Primary Hydro Test 1.33 1 33 x Pdesign 1.25 1 25 x Pdesign Pressure 3300 psi Typically ~3100 psi Stub Runner Low Strength Yes U.S. DP and stub runners Divider Plate High Strength mechanical properties are within A600 material spec limits Plant Load Follow Yes No
20
EdF Divider Plate Cracking Update 900 MW SG Inspection Frequency as proposed for approval by the French Regulator
- If SCC defects are detected that are <2mm deep, inspect every 10 years
- If SCC defects are detected that are >2mm and
<4mm deep, inspect every 4 years
- If SCC defects are detected that are >=4mm deep, inspect every 2 years 21
EdF Divider Plate Cracking Update 1300 MW SG Inspection Frequency as proposed for approval by the French Regulator
- Thicker divider plate, 60mm (2.36)
- All but 5 units have been inspected at least one time
- 5 units have still to be inspected in order to inspect all heats at least one time
- No SCC identified or expected
- If no SCC, no additional inspections All Alloy 600 divider plates will be inspected at the triple point every 10 years 22
EdF Divider Plate Cracking Update Summary
- NDE and DE have provided a good understanding of the local strain history on components affected by SCC
- Divider Plate Components with SCC share the following characteristics:
- Divider plates supplied by one material vendor and were heat treated at high temperatures that promoted intra carbides and high carbide levels.
- Stub runners had low mechanical properties while divider plate had high mechanical properties promoting plate deformation that was not anticipated
- High hydrostatic pressure tests may have promoted divider plate deformation
- SCC always located in most significantly strained areas. SCC not found with components with no significant plastic deformation.
- SCC has not been found in the triple point.
23
Divider Plate/Cladding Cracking EPRI SGMP Draft Work Scope for 2011 and 2012 Helen Cothron, EPRI Chris Cassino, Westinghouse 24
Project Objectives Objective 1: Determine the chromium content in the as-constructed Alloy 82/182 clad tubesheet and Alloy 690 tubing j
Objective 2: Determine if cracks can propagate from the divider plate to other components and affect the integrity of the primary pressure boundary Two year SGMP project
- Funding approved for 2011.
25
Objective 1: Cracking in Alloy 600 Cladding Task 1: A literature review of crack growth rate studies
- Review of the data supporting conclusions
- Review of outliers and any data pertaining to the directionality of crack propagation Task 2: Obtain small boat samples for chemical analysis of cladding and final as-built tube end welds in typical SGs with Alloy 82 cladding and Alloy 690 tubing
- Potential sources of these specimens are replacement SG manufacturers.
26
Objective 2: Divider Plate Cracking Task 1: Finite element analysis to determine what conditions are necessary for cracks in the divider plate to propagate in any one of the following three paths (1) Initiating in the stub runner to tubesheet connection and propagating to an adjacent tube end weld (2) Initiating in the divider plate or stub runner material and propagating to the base metal of the channel head (3) Initiating in the divider plate or stub runner material and propagating to the base metal of the tubesheet.
The goal of the study will be to evaluate what is necessary to turn the crack path from the divider plate into the components of the primary pressure boundary. 27
Objective 2: Divider Plate Cracking Task 2: If Task 1 concludes that cracks can propagate as proposed, perform a feasibility study for designing and assembling mock-ups for testing of the possible crack propagation modes
- Results could be used to estimate crack growth rates and guide potential inspection methodology
- The feasibility study will determine if appropriate testing materials are available and if it would be practical to perform such tests 28
License Renewal Issues Helen Cothron, EPRI Jay Smith, Exelon 29
License Renewal Issues Divider Plate Cracking Due to NRC License Renewal staff RAI, plants are committing to divider plate inspections once they have entered the extended period of operation operation.
Utilities will use SGMP project results to validate or change their commitments.
30
License Renewal Issues Tube Sheet Cladding Cracking Recent RAI on tubesheet cladding cracking postulates that cracking may initiate in the Alloy 600 cladding material and then propagate to the 600/690 weld at the tube end Utilities are committing to inspection of this area after entering the extended period of operation Utilities will use SGMP project results to validate or change their commitments.
31
License Renewal Issues Primary Side Fouling Update During the August 12, 2010 SGTF meeting, it was discussed that a number of units have identified primary side fouling as a SG aging effect in their license renewal applications.
Given the lack of information on the occurrence of primary side fouling in domestic SGs, the NRC Staff asked the Ind str to pro Industry provide ide additional information on primar primary side fouling.
The industry agreed to discuss this issue with licensees that included primary side fouling in their license renewal application to determine the reason for its inclusion.
- The NRC presented to the SGTF a list of 9 plants that included primary side fouling in their license renewal requests.
32
License Renewal Issues Primary Side Fouling Update SG primary side fouling was discussed at recent License Renewal Task Force (LRTF) and Implementation Working Group meetings.
- After discussions, it was concluded that SG primary side fouling was not an aging mechanism and should not be included in future applications.
- Possible reasons for inclusion included using generic heat g GALL template exchanger p for SGs and/or mis-understanding g of the GALL requirement.
Conclusion:
SGTF does not consider SG primary side fouling an aging mechanism.
- The identified plants that included primary side fouling were contacted and they understand that primary side fouling is not considered an aging mechanism.
- Changes to LRA is a plant specific decision.
Recommended Actions
- SGTF to communicate conclusion to LRTF
- NRR to communicate conclusion to NRC License Renewal Branch 33
Pre-Service Inspection Code Guidance Viki Armentrout, Dominion Jay Smith, Exelon 34
Pre-Service Inspection Code Guidance NRC Comment regarding Pre-service Examination of SG tubing:
- IWB-2200(c) of Section XI of the ASME Code indicates that steam generator tube examination shall be governed by the plant Technical Specification. The technical specifications do not address pre-service inspections. Discuss with the industry a path forward to address this issue (e.g., incorporating pre-service inspections into TSTF-510, modifying the ASME Code).
35
Pre-Service Inspection Code Guidance Action sent out for review and was presented to WGISC in February 2010
- NRC Working Group attendee indicated that the revised wording would not be endorsed by NRC.
- Per NRC, reference to steam generator preservice inspections should be removed from IWB-2200(c) and Table IWB-2500-1 should be modified.
- ASME item BC 10-129 already in place to modify the steam generator inspection requirements.
- Item was not moved for vote based on need to resolve this NRC comment.
- The best likely date to achieve NRC approval in 10CFR50 will be 2015.
Auto-Analysis Workshop Summary Steve Swilley, EPRI 37
Auto-Analysis Workshop Summary Charlotte, NC, February 9th and 10th, 2011
- The EPRI Steam Generator Management Program invites you to attend a workshop in Charlotte, NC at EPRI on February 9th and 10th, 2011. The work shop will focus on the use of automated analysis tools for inspection of steam generator tubing. Although automated analysis tools have been used in the industry since the 1980s, there have been many significant advances in the software technology. This workshop will include utility, vendor, and regulatory updates on existing technology, current practice, field experience, and future directions.
38
Auto-Analysis Workshop Summary EPRI Steam Generator Automated Analysis Workshop Charlotte. NC Room 402 Analysis of Bobbin Probe Inspection Data from SG Mock-up Session'" - Ope-rating Expeorif'llCeS 3:05 PM I Recent Field Experience willi EADS &RTAA Westinghouse Electric Co.;
39
Auto-Analysis Workshop Summary EPRI Steam Generator Automated Analysis Workshop Charlotte. NC Thlll'sday February 10, 2011
- Westinghouse
- Zetec
- Industry
Auto-Analysis Workshop Summary 64 Attendees
- 25 Vendor
- 16 Utility
- 15 NRC
- 2 Research
- 6 EPRI
- 11 were non US (Canada, Spain, Japan, France, Germany, and Croatia) 41
Auto-Analysis Workshop Summary Industry Perspective NRC Perspective 42
U-Bend Axial Outer Diameter Stress Corrosion Cracking Inspection Technique Peer Review Steve Swilley, EPRI 43
U-Bend Axial Outer Diameter Stress Corrosion Cracking Inspection Technique Peer Review ETSSs Peer Reviewed August 2010
- Detection of Axial ODSCC in Low Row U-Bends
- ETSS 10411, Plus Point Coil
- Includes Phase and Amplitude Sizing
- ETSS 10413, X-Probe
- Detection Only
- ETSS 10414, I-Probe
- MIDAS analysis software
- ETSS 10415, I-Probe
- EddynetSuite analysis software Techniques Available for Industry Use 44
Upcoming Changes to Industry Documents Jim Benson, EPRI 45
SGMP Industry Document Status and Revision Schedule Last Implementa I .
G ui del ine Tide I Current I Report I Pub .
tlon Interim I Guidance n:_ :r" I Comments Rev # # Date ~)
SG Integrity 10190 Nov- SGMP-Assessment 3 9/1.12010 38 09 IG-10-o1 Guidelines SG In-Situ 10149 Aug- 3/1412008 Rev 4 in Pressure Test 3 none 83 07 6 /14/2008 progress Guidelines PWRSG Examination I 7 I 10137 Oct-9/1.12008 SGMP-IG- Rev 8 in 06 07 08'()4 progress uUlut=lnlt=~
PWRSG Rev 4 in Primary-to- progress.
10082 Dec- 7 /17/2006 Secondary 3 none Expected to 19 04 10117.12006 Leakage be issued by Guidelines Dec 2011 46
SGMP Industry Document Status and Revision Schedule 47
SGMP Administrative Procedures, Revision 3 Revision 3 has been endorsed by the PMMP EC Published in December 2010 The SGMP IC will be drafting an Implementation Letter Draft Implementation Letter was intentionally delayed to allow issuance at about the same time as NEI 97-06, Rev 3 On Jan 12th, the IC:
- Endorsed draft NEI 97-06, Rev 3
- Recommended a utility implementation date of Sept 1, 2011
- Dec 31, 2011 for utilities with a spring 2011 outage
- EPRI implementation will be immediate The Implementation Letter will be signed by the PMMP EOC Chair prior to issuance
- Letter expected to be issued in Feb 2011 48
SG Operating Experience Russ Lieder, Nextera Energy Seabrook, LLC 49
SG Operating Experience Objective of OE presentation and approach for future meetings OE is extensively discussed amongst utilities in non-public meeting 50
Implementation of Noise Monitoring Techniques Helen Cothron, EPRI 51
Implementation of Noise Monitoring Techniques Vendors have the capability to monitor noise SGMP has worked with the vendors to ensure the output can be easily transferred to available software to recalculate probability of detection if necessary Lessons learned have been recorded during three pilot projects
- Alloy 690TT replacement SGs
- Alloy 600TT original SG One additional pilot is planned for 2011
- Alloy 600MA SG with multiple degradation mechanisms
- This experience is necessary prior to developing recommendations Revision 8 of the PWR Examination Guidelines is underway during 2011/2012 and will consider recommendation/requirements for noise monitoring Some plants are experimenting with the noise monitoring capabilities and are providing feedback to SGMP 52
Follow-up on Previous Meetings 53
Future Topics 54
NRC feedback on various issues TSTF-510 AVB Position Verification 55
Address Public Q
Questions/Comments ti /C t 56
Adjourn 57