ML20197H984

Summary of 981112 Meeting with BWROG Weld Overlay Insp Relief Committee in Rockville,Md Re Upcoming Topical Rept Being Prepared by EPRI Re Reduction in Frequency for Weld Overlay Insp.List of Attendees & Presentation Encl

ML20197H984
Person / Time
Issue date:	12/10/1998
From:	Marlone Davis NRC (Affiliation Not Assigned)
To:	Essig T NRC (Affiliation Not Assigned)
References
PROJECT-691 NUDOCS 9812140224
Download: ML20197H984 (35)

Text

1. y December 10, 1998 MEMORANDUM TO: Thomas H. Essig, Acting Chi:f Generic issues and Environmental Projects Branch Division of Reactor Program Management, NRR FROM:

Michael J. Davis, Project Manager Original Signed By:

Generic Issues and Environmental Projects Branch Division of Reactor Program Management, NRR

SUMMARY

OF PUBLIC MEETING HELD ON NOVEMBER 12,1998, WITH THE BOILING WATER REACTOR OWNERS' GROUP (BWROG)

WELD OVERLAY INSPECTION RELIEF COMMITTEE On November 12,1998, the staff held a public meeting with representatives of the Boiling Water Reactor Owners' Group (BWROG) Weld Overlay inspection Relief Committee at NRC Headquarters in Rockville, Maryland. The purpose of the meeting was to discuss an upcoming topical report being prepared by the Electric Power Research Institute (EPRI) concerning a reduction in the frequency for weld overlay inspections. A list of attendees and their affiliations is provided as Attachment 1. A copy of the handout used in the BWROG presentation is provided as Attachment 2.

A BWROG representative began the meeting with a brief update on the Weld Overlay inspection Relief Committee's activities. The committee was formed several months ago after it was determined that a Brunswick submittal for relief could be better handled by a generic communication. The topical report submittal is scheduled for February 1999, with the goal of having the report approved and available for implementation during Fall 1999 outages. Seven utilities / plants are participating in this Committee, which represents 95% of the installed overlay base.

A total of 647 inspections have been performed to date on 158 weld overlays, with no degradation identified. The BWROG feels that inservice inspection (ISI) relief is appropriate for existing and future weld overlays.

The EPRI representative summarized the draft topical report on the EPRI Weld Overlay ISI Program. It will be proposed that overlay inspections revert from Category E to Category A interval after three successive IS!s. The StructuralIntegrity Associates, Inc. representative presented technical justification for increasing the interval between inspections of weld overlay

/

repairs. The staff indicated that the topical report would have to be referenced in one or more

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plant specific submittals to obtain priority for the staff review. The BWROG acknowledged this point and indicated that they would get a lead plant, probably one with a significant number of overlays on reactor coolant pressure boundary piping.

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MEMORANDUM TO: Thom:s H. Essig, Acting Chi::f Generic issues and Environmental Projects Branch Division of Reactor Program Management, NRR

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Generic Issues and Environmental Projects Brang FROM:

Michael J. Davis, Project Manager Division of Reactor Program Management, NRp'

SUMMARY

OF PUBLIC MEETING HELD,0N NOVEMBER 12,1998, WITH THE BOILING WATER REACTOp' OWNERS' GROUP (BWROG)

WELD OVERLAY INSPECTION RELJEF COMMITTEE On November 12,1998, the staff held a public meetingyvith representatives of the Boiling Water Reactor Owners' Group (BWROG) Weld Overla9 Inspection Relief Committee at NRC Headquarters in Rockville, Maryland. The purpose the meeting was to discuss an upcoming topical report being prepared by the Electric Pow Research Institute (EPRI) concerning a reduction in the frequency for weld overlay inspettions. A list of attendees and their affiliations is provided as Attachment 1. A copy of the haddout used in the BWROG presentation is provided as Attachment 2.

A BWROG representative began the m ting with a brief update on the Weld Overlay inspection Relief Committee's activitie The committee was formed several months ago after it was determined that a Brunswick spsubmittal is scheduled for February 1999 mittal for relief could be better handled by a generic communication. The topical repo -

having the report approved and ailable for implementation during Fall 1999 outages. Seven utilities / plants are participatin n this Committee, which represents 95% of the installed overlay base.

A total of 647 inspection ave been performed to date on 158 weld overlays, with no degradation identified. he BWROG feels that inservice inspection (ISI) relief is appropriate for existing and future w d overlays.

The EPRI repres ntative summarized the draft topical report on the EPRI Weld Overlay ISI Program. It wi e proposed that overlay inspections revert from Category E to Category A interval after ree successive Isis. The StructuralIntegrity Associates, Inc. representative presented chnical justification for increasing the interval between inspections of weld overlay j

repairs.

ome discussion followed on elements the staff would like to see included in the topical; port.

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'b'C:EMCB RAbfl NAME MDavis:SW TSullivan DATE 12/ 1 /98 12/3 /98 12/ /98 OFFICIAL RECORD COPY

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• December 10, 1998 MEMORANDUM TO: Thomas H. Essig, Acting Chief Generic issues and Environmental Projects Branch Division of Reactor Program Management, NRR

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FROM:

Michael J. Davis, Project Manager Generic issues and Environmental Projects Branch Division of Reactor Program Management, NRR

SUMMARY

OF PUBLIC MEETING HELD ON NOVEMBER 12,1998, WITH THE BOILING WATER REACTOR OWNERS' GROUP (BWROG) i WELD OVERLAY INSPECTION RELIEF COMMITTEE On November 12,1998, the staff held a public meeting with representatives of the Boiling Water Reactor Owners' Group (BWROG) Weld Overlay inspection Relief Committee at NRC Headquarters in Rockville, Maryland. The purpose of the meeting was to discuss an upcoming topical report being prepared by the Electric Power Research Institute (EPRI) concerning a reduction in the frequency for weld overlay inspections. A list of attendees and their affiliations is provided as Attachment 1. A copy of the handout used in the BWROG presentation is provided as Attachment 2.

A BWROG representative began the meeting with a brief update on the Weld Overlay inspection Relief Committee's activities. The committee was formed several months ago after it was determined that a Brunswick submittal for relief could be better handled by a generic communication. The topical report submittal is scheduled for February 1999, with the goal of having the report approved and available for implementation during Fall 1999 outages. Seven utilities / plants are participating in this Committee, which represents 95% of the installed overlay base.

A total of 647 inspections have been performed to date on 158 weld overlays, with no degradation identified. The BWROG feels that inservice inspection (ISI) relief is appropriate for i

existing and future weld overlays.

The EPRI representative summarized the draft topical report on the EPRI Weld Overlay ISI Program. It will be proposed that overlay inspections revert from Category E to Category A interval after three successive Isis. The Structural Integrity Associates, Inc. representative presented technical justification for increasing the interval between inspections of weld overlay repairs. The staff indicated that the topical report would have to be referenced in one or more plant specific submittals to obtain priority for the staff review. The BWROG acknowledged this point and indicated that they would get a lead plant, probably one with a significant number of overlays on reactor coolant pressure t'oundary piping.

Project No. 691 Attachments: As stated cc w/ atts: See next page

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- LIST OF ATTENDEES AT MEETING WITH BWROG HELD IN ROCKVILLE, MARYLAND ON NOVEMBER 12,1998 i

NAME AFFILIATION M. Davis NRC R. Hermann NRC l

J. Spanner EPRI K. Sedney GE-BWROG R. Penny NYPA B.' Gordon SIA, Inc.

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ATTACHMENT 1

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l BWR OWNERS' GROUP 6

I WELD OVERLAY INSPECTION

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i RELIEF COMMil i EE i

i Introduction Kathy Sedney, GE Robert Penny, NYPA i

Presentation to NRC i

November 12,1998 i

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,l Agenda i

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Introduction and Summary of l

BWROG Program Kathy Sedney (GE) t Summary of Utility Experience Bob Penny -(NYPA) j E

i Summary of EPRi Topical Report Jack Spanner (EPRI)/

l Barry Gordon (SI) i Discussion All i

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BWROG Committee Objective i

Review and Coordinate NRC submittal of an EPRI-prepared topical report which will justify reducing the frequency for weld overlay inspections NRC submittal is targeted for February,1999 The Committee is working toward the goal of having the topical report approved and available for implementation for Fall,1999 outages i

Utilities / Plant' participating in this Committee:

s CP&L, Comed, GPU, Alliant, NYPA, PECO Energy, SNC l

Brunswick 1/2, Dresden 2/3, Quad Cities 1/2, Oyster Creek, Duane Arnold, Fitzpatrick, Peach Bottom 2/3, Hatch 1/2 i

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Introduction l

i e NRC currently considers WOs an interim repair:

- NUREG-0313 Rev,2 Category E:

inspection at least once every 2 refueling cycles, ~50% WOs inspected during first refueling outage after repair I

I e BWROG proposes to extend inspection frequency to Category A.

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Summary of Recommended Inspection Schedules for BWR Weldments Description of Weldments IGSCC Inspection Notes Category Extent & Schedule Resistant Materials 2.5% cvery 10 years 4

A (at least 12% in 6 years)

Nonresistant Materials 50% every 10 years SI within 2 years ofoperation (1)

(1)

B (at least 25% in 6 years)

Nonresistant Materials All within the next 2 refueling SI after 2 years of (1)

C cycles, then all every 10 years opemtion (at least 50% in 6 years)

Nonresistant Materials All every 2 refueling cycles NoS1 (1)

D Cracked 50% next refueling outage, then Reinforced by Weld (1)(2)

E all every 2 refueling cycles Overlay or Mitigated by SI Cracked Inadequate or no repair (2)

F All every refueling outage Nonresistant Not Inspected (3)

G All next refueling outage Notes:

(1)

All welds in non-resistant material should be inspected after a stress improvement process as part of the process. Schedules shown should be followed after this initial inspection.

(2)

See recommendations for acceptance weld overlay reinforcements and stress improvement mitigation.

(3)

Welds that are not UT inspectable should be replaced, " sleeved," or local leak detection applied. RT examination or visual inspection for leakage may also be considered.

.l Weld Overlay History e 1982 - first WO application - NRC considers WO only as an interim repair until next outage e 1984 - NUREG-1061 - allows one additional fuel cycle l

e 1984 - EPRI and BWROG issues a report for continued WO service e 1986 -lab tests and UT procedures suggest WO life is j

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>22 fuel cycles j

e 1987 - NUREG-0313 Rev. 2 and BPNL provide technical support for WO as a long-term remedy with continued ISI i

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k Weld Overlay History (continued) 4 i

e 1988 - EPRI NP-5881-LD report - UT, metallography and l

reversing DC EPM tests reveal complete crack i

propagation mitigation e 1991 - EPRI NP-7103-D report issued justifying extended WO service issued i

e 1992 - WO accepted as Code approved repair (N-504) e 1994 - NRC accepts Code Case in Regulatory Guide 1.147 e 1998 - EPRI and BWROG prepare technical justification to the NRC for consideration of ISI relief i

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,j WO ISI Relief Radiation Exposure and Cost Considerations e Significant person-Rem and cost savings e FitzPatrick 8 person-Rem saving/ outage j

- 100 - 125K cost savings / outage including craft j

labor, inspectors, radiation technicians, etc.

j e Brunswick j

- 72 person-Rem /$1M savings over current operating license e Hatch 1 l

- 38 person-Rem saving/ outage

- 227K saving/ outage not including craft support

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l Purpose of Report o

Purpose of this technical justification report is to i

demonstrate that:

1. Existing WOs at several BWRs have been j

volumetrically examined consistent with NUREG-0313 Rev. 2

2. None of those inspections have identified any degradation of the design margins of WOs repairs due to either IGSCC propagation into the WO or any other mechanism l

3. Based on these inspections and observations, ISI relief is appropriate for existing and future WOs, i.e., chanae WO ISI cateaory from E to A c

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l Conclusions i

e Inspection data on 158 WOs has been provided to j

date, 4

i e A total of 647 WO-inspections have been j

performed j

e No WO degradation has been identified i

e it is anticipated that additional inspection data will further suppo.rt the excellent performance of WOs i

e As a result of these inspections and observations, ISI relief is appropriate for existing and future WOs

l Summary of EPRI Weld Overlay ISI Program i

Presented by l

Jack Spanner Office: (704) 547-6065 Fax:(704) 547-6028 E-Mail: jspanner@l.epri.com l

l Electric Power Research Institute l

NDE Center 1

White Flint November 12,1998 k

.l Technical Justification to Increase Interval Between Weld Overlay Examinations Will be based on CP&L's Brunswick Request for Relief

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- No crack propagation detected after 3 inspections

- Water chemistry mitigation

- Weld overlays meet current Code requirements Overlay inspections revert to Category A interval after three successive ISI's L T procedures will be demonstrated through PDI i

History of ET Qualifications January 1984 IGSCC Detection @ NDEC August 1984 IGSCC Sizing @ NDEC Sept.1985 IGSCC Detection Requal January 1988 Weld Overlay UT Quals April 1994 PDI IGSCC Qualification begins May 1994

~ NRC grants 2 year extension to 3 -Party Agreement Quals March 1996 NRC accepts PDI IGSCC Quals, Weld Overlay currently done to Coordination plan by PDI i

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5 EPRI Team i

-Major Component Reliability-

{

Bob Carter

-XDE Staff Frank Ammirato, Jeff Landrum/Stan Walker

-Structural Integrity-Barry Gordon i

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StructuralIntegrity Associates, Inc.

Technical Justificationfor the Extension of the Interval Between Inspections of Weld Overlay Repair l

i Presentation to the NRC Rockville, MD B. M. Gordon 1

November 12,1998 i

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Introduction l

Weld overlays (WOs) mitigate IGSCC

- stainless steel, (e.g., Type 308/309L}, and high Cr/ low C nickel-base weld materials, (e.g.,

Alloys 82 and 52), are highly resistant to IGSCC

- full structural reinforcement to restore 1

original piping safety margins i

- produce. compressive residual stresses l

- clearly demonstrated by laboratory and field i

experience of >16 years to mitigate IGSCC

- extra IGSCC margin due to widespread HWC l

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i isolated Cases of Weld Metal Cracking l

l e NMP-1 recirculation piping cracking

- 2 of 28 samples had cracks penetrating in low ferrite regions, (e.g.,3.8-4.2 and 3-6%)

- possible contributory roll of hot cracking

- crack arrest in high ferrite region l

e Quad Cities 2 core spray line 4

- 5% ferrite, high carbon (0.064%)

- crack arrest in high ferrite region l

WO Crack Growth Rate Evaluations e

WO crack growth test program, no crack growth

-UT

- Metallography

- reversing DC EPM e

WO crack growth modeling

- stress intensity calculations reveal K < 0

- no crack ~ extension e

Residual stress FEA modeling

- highly compressive axial and hoop stress

- no effect of pipe diameter l

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Stress Intensity Factor for Hope Creek

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Effect of Diameter on Through-wall Weld Overlay Axial Residual Stress I

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RiskInformedISI(RISI) Analysis e Significant resources currently committed to non-optimal ISI programs e An alternative risk informed approach is based on service experience and failure consequence

- more focused ISI program

- reduction in person-Rem and costs j

-issued as ASME Code Case N-560 e Two elements: degradation mechanism (IGSCC) and consequence of failure evaluations j

e IGSCC events are considered "small leaks"

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e WOs are good candidates for EPRI RISI e Use Risk insight to show changing ISI frequency (E>A) j introduces negligible risk increase j

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Report Methodology e Review inspection records for each augmented j

inspection performed after WO application j

e Review as-built WO dimensions and data e Demonstrate that older WOs are structurally adequate j

e Demonstrate that IGSCC is no longer active at WO locations i

e Demonstrate that WOs with no degradation over 3 successive inspections is IGSCC mitigated

• Demonstrate WO inspection can be returned to a normal inspection interval, i.e., Category A

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Weld Overlay Design Basis l

e WOs thickness designed to ASME Section XI, IWB-3640 i

e Weld material is low C stainless steel /Ni alloy applied 360 degrees around pipe e initial PT examination of pipe surface e At least two layers delta ferrite > 7.5 FN e Designed for 360 degrees /through-wall defect e Repair extends > 0.75kRt beyond flaw in each direction, transition angle < 45 l

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l Weld Overlay Design Basis (continued) l i

l e GTAW welding process for high toughness j

e Minimum two weld layers with FN > 7.5-if <4 axial flaws identified e Residual stress due to WO are considered in flaw growth calculations e Weld shrinkage must be evaluated j

e Completed repairs must be pressure tested e Completed repair must be examined by PT and UT l

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Hydrogen Water Chemistry l

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e Mitigates IGSCC initiation and propagation i

e 37 US BWRs using/ installing / planning HWC 1

e NUREG-0313 - 5.3.3

- time schedule for inspections may be i

extended with HWC

- case-by-case basis

-inspections typically lengthened by 2x for f

category B, C, D and E weldments I

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Utility Sources of WO Information Utility BWR Number of Weld Overlays Carolina Power and Light Brunswick 1 10 Carolina Power and Light Brunswick 2 14 New York Power Authority FitzPatrick 23 Southern Nuclear Operating Company Hatch 1 54 PECO Energy Peach Bottom 2 2

PECO Energy Peach Bottom 3 6

IES Utilities Duane Arnold 9

Commonwealth Edison Dresden 2 38 Vermont Yankee Nuclear Power Corp.

Vermont Yankee 2

Total 158

Sample of WO ISI Data (Brunswick 1) t Year Inspee-Inspection Mett ad Results Comments Overlay tion Applied Year 1987 1987 PT No Recordabic Indications Performed on surface after weld overlay reduction, prior to UT examination UT No indications associated with Examination only from downstream Manual using 60' RL, IGSCC were recorded (pipe) side of weld due to e

OD Creeping Wave, configuration of the weld-o-let andO'L Thickness measurement:

Pipe wall 0.32", pipe plus overlay 0.64" Weld overlay lesagth 1.65*

1990 UT No indications associated with e Axial and circ scans done in both Manual using 60* RL IGSCC were recorded directions on each side of original e

and OD Creeping weld Wave e

Previous data reviewed-no significant change noted 1995 UT No indications associated with Axial and circ scans done in both e

Manual using 60' RL IGSCC were recorded directions on each side of original e

and OD Creeping weld Wave

=

Previous data reviewed-no significant change noted 1

Sample of WO Geometry Data (D-2)

Weld in Omlay Pigr Configuration Pipe Wallihickness Gerlay lhickness inv FN First Oulaylrngth Adal tne Size,in ipstream dower;tream upstram downstream up;tream downstream larrlhickness

'1T "A"

Strinky 8-12 2

8 pipe vahe 0.50L)

N'A 0353 N'A N'A N'A 3.5 1.5U 0.089 8-K12 1

8 elbow pipe 0.600 0.515 0248 0235 N'A N'A 3.8 1.9D 0305 8-Kl3 1

8 pipe citov 0335 0.550 0290 0300 NA NA 32 1.6U 0320 8-14 I

8 pipe ellev 0.520 0.555 0285 0.270 N'A NA 53 2.711 0375 8-K14 I

8 elbow pipe 0.583 0.520 0.523 0333 0 098 0.180 4.1 2.0U 0.324 8-15 1

8 elbow pipe 0.530 0.590 0.351 0280 N'A N'A 4.0 2.0U 0.367 8-K15 1

8 pipe bert pipe 0.520 0.520 0310 0365 N'A NA

' 4.6 23U 0387 8-16 1

8 elbow pipe 0.605 0.500 0313 0335 NA N'A 4.4 22U 0.235 8-K16 1

8 pipe elbow 0.550 0323 0.745 0347 N'A N'A 43 22U 0305 8-K17 I

8 pipe eltuv 0.530 0323 0335 0317 N'A N'A 4.0 2.00 0344 PDI-D15 1

12 cibow pipe 0.658 0.598 0352 0.460 N'A N'A 5.2 2.60 0 346 PDI-Ol6 1

12 pipe eltuv 0.620 0.675 0.538 0343 N'A N'A 4.6 23D 0.408 PDl/12 2

12 redixxr pipe N'A 0.625 N'A 0.458 N'A N'A 4.2 2.0D 0375 IMD4 1

12 elbow pipe 0.685 0.620 0327 0370 N'A N'A 4.7 2.4D 0215 I M D5 I

.2 pipe eltuv 0.620 0.685 0333 0300 NA NA 4.9 23D 0.2 75 103-D1 I

i 12 elbow pipe 0.675 0.615 0360 0.415 N'A N'A 4.7 2.4D 0.256 ID3-D2 1

12 pipe eltuv 0.603 0.658 0.433 0368 N'A N'A 5.0 2.5D 0.196 PDt-D22 1

12 elbow pipe 0.715 0.620 0278 0398 N'A N'A 4.6 2JD 0266 IMD23 1

12 pipe ettvv 0.600 Oh10 0375 0375 N'A N'A 4.7 2.4D 02M IMD20 1

12 elbow pipe 0.695 0.635 0.455 0.430 N'A N'A 5.1 2.6D 0.261 EDS-D21 1

12 pp elbow 0.610 0.685 0.423 0357 NA NA 4.7 2.4D 0248 EMD18 1

12 elbow pipe 0.680 0.615 0388 0.475 N'A N'A 4.6 2.3D 0377 IMD19 1

12 pipe eltav 0398 0.663 0385 0340 N'A N'A 4.9 2.5D 0350 t

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Project No. 691 Boihng Water Reactor Owners Group l

cc:

Thomas J. Rausch, Chairman W. Glenn Warren Boiling Water Reactor Owners' Group Southem Nuclear / Georgia Power Commonwealth Edison Company E.1, Hatch Nuclear Plant Nuclear Fuel Services PO Box 1295 M/C B052 1400_ Opus Place,4th Floor ETWill Birmingham, AL 35201-Downers Grove,IL 60515 s

1 Carl D. Terry Dennis B. Townsend.

Vice President, Nuclear Engineering GE Nuclear Energy.

Niagara Mohawk Power Corporation M/C 182 Nine Mile Point-2 175 Curtner Avenue j

PO Box 63 San Jose, CA 95125 l

Lycoming, NY 13093 Drew B. Fetters -

Thomas A. Green i

PECO Energy GE Nuclear Energy l

Nuclear Group Headquarters Mail Code 182 MC 62C-3 175 Curtner Avenue 965 Chesterbrook Blvd.

San Jose, CA 95125 Wayne, PA 19087 1

John Hosmer i

Commonwealth Edison Executive Towers,4th Floor 1400 Opus Place Downers Grove,IL 60515 George T, Jones Pennsylvania Power & Light MC A6-1 Two North Ninth Street Allentown,PA 18101 Lewis H. Sumner South 6m Nuclear / Georgia Power E. I. Hatch Nedear Power Plant 40 invemess Parkway PO Box 1295 Birmingham,GA 35201 John Kelly New York Power Authority 14th Floor Mail Stop 14K Centroplex Building 123 Main Street White Plains, NY 10601 i

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