ML023120269
| ML023120269 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 11/07/2002 |
| From: | Alexion T NRC/NRR/DLPM/LPD4 |
| To: | |
| Alexion T W,NRR/DLPM,415-1326 | |
| Shared Package | |
| ml023170275 | List: |
| References | |
| Download: ML023120269 (39) | |
Text
ANO-1 Reactor Vessel Nozzle Repair Entergy Operations Inc.
October 16, 2002 0
0 (D,
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Agenda
- Introduction/Purpose Craig Anderson
- 1 R16 (Spring 2001) Findings/Repair William Sims
- o 1R17 NDE Findings Steve Lewis
- o1 R1i7 Weld Repair Details William Sims
- oEvaluation of Weld Repair Steve Lewis
- Assurance for Not Having Leakage Path to Steve Lewis Annulus o Safety Perspective Mike Krupa
- -Concluding Remarks Craig Anderson 2
Introductory Remarks Craig Anderson 3
Status of ANO-1 CRDM Nozzle Examinations
- o100% Bare Metal Visual Exam Completed
> Periphery Nozzle 56 was identified to be leaking o:*Volumetric Examinations in Progress
+ Liquid Penetrant and Eddy Current Exams Performed on Nozzle 56 4
1R16 (Spring 2001)
Findings/Repair William Sims Entergy A600 Technical Lead
Repairs Performed During 1R16 on Nozzle 56
- Visual Inspection Performed Identified Nozzle 56 was the Only Leaking Nozzle
- LUT and PT Performed
> Flaw was determined to be axial in the weld to nozzle interface at -30 degrees from low hill side
> Extended above J-weld in the nozzle
> Circumferential flaw in nozzle below J-weld 6
Repairs Performed During 1R16 on Nozzle 56 (cont.)
- Severed Nozzle above the OD Circ Crack
- -Excavated the Flaw in nozzle/J-Weld to Butter Region At Triple Point
1R17 NDE Findings Steve Lewis Supervisor, Engineering
Status of Current Findings of Examinations of CRDM Nozzles 4*Top Head Bare Metal Visual Inspections
> Nozzle 56 Determined to be the only leaking nozzle I No evidence of wastage 9
1R17 Nozzle 56 Boric Acid 10
1R17 Post Cleaning of Nozzle 56 A 4,
-- r 11
Status of Current Findings of Examinations of CRDM Nozzles (cont.)
Nozzle 56 Ultrasonic Data
+ Four Indications Adjacent to 1 R1i6 Weld Repair
+ Two Indications on Hill Side of Nozzle Flaw # Depth Length Az. Above Below 1A 0.177 0.56 200 .16 --
2A 0.145 0.44 370 .12 --
4A 0.177 0.28 1750 .16 --
5A 0.125 0.6 1640 0 .12 1C 0.266 0.4 240 -- .
2C 0.180 0.68 390 .32 -
- With uncertainty below weld only
- No Indications Identified to Have Circumferential Extent 12
PT Layout of Nozzle 56 (General Representation)
Up Hill Side 180° 082/182 Weld Butter Area-,
270O RI~.062" RI-.100" R1-.062'
- R!-.062" R1-.062" RI-.03" General Area 0D of 1R16 Weld R1-.185 Down Hill Side Repair 13
Preliminary Results of Nozzle 56 Findings
- . No Evidence of Alloy 052 cracking
- No Wastage Identified at Nozzle Bore Annulus Area from Bare Metal Visual Inspection (Boric Acid Showed No Discoloration) 14
1R17 CRDM Nozzle Weld Repair William Sims Entergy A600 Technical Lead
Design Repair Objectives
- Maintain Safe Operation of the Unit
> Provide ASME Code Compliance for Two Cycles of Operation e Maintain Code margins
> Isolate the Flaw from the PWSCC Environment o Use of PWSCC resistant material e Control of repair processes SNo leaks
- oIncorporate Lessons Learned 16
Incorporate Lessons Learned ANO North Anna Exposed Crack
.82/182 Weld ! 152 Weld Overlay Exposed 82/182 Weld Potential IRI 7,,
Crack Locations 17
Description of Weld Repair Option-4
, Embedded Flaw Repair Features (used in combination or individually)
S3600 J-Groove weld and butter overlay
> 3600 Nozzle inlay or overlay Overlay
> 900 Nozzle inlay SWeld overlay on nozzle OD surface to mitigate crack initiation
- Or Just Remove The Flaw Overlay Inlay 18
Weld Repair Process
- oIdentification of 082/182 Material Boundary
> Entergy will identify boundary between existing 082 material and SS clad using "ferrite" tool
> Marks will be applied to location of 082/182 SS clad interface to identify boundary
> Personnel will be trained and qualified by blind mockup
> Independent verification will be performed SWelds will overlap SS Clad by a minimum of 1/2" I Written instructions will control this process 19
Weld Repair Process
- Weld Process Applied at ANO-1
> J-weld overlay will be at least 3/8" thick (minimum-of 3 layers)
> Surface exam of J-weld overlay and nozzle inlay
> Volumetric exam of nozzle inlay
> Visual of weld surfaces 20
"Weld Repair Design Steve Lewis Supervisor, Engineering
Weld Repair Design
- Repairs were Designed by Detailed State of the Art Analysis
> Repairs are Designed by Detailed 3D FE Analysis
> Stress determination performed by Dominion Engineering SAll other analysis performed by Structural Integrity Associates 22
Weld Repair Design (cont.)
- 4oTesting and history to date has shown that 052 integrity is established for greater than two cycles SEPRI NP-3061, SSC of A600 and A690, May 1983
"* Tests @ 680'F for 6300 hrs
"* Could not get 052 to crack due to PWSCC
> McDermott Tech Report, Evaluation of 82, 152 and 052 SSC, Constant Extension Rate Tests performed
- 152(052) Materials tested at 6500F
> Westinghouse Bettis Pub. PWSCC Crack Growth (1999) 23
Weld Repair Design
- -Westinghouse Bettis Publication on PWSCC Crack Growth Results for Alloy 82H and Alloy 052
> Fracture mechanics crack growth test a 3600C (680 0 F)
> Results compared to industry data
> Alloy 82H crack growth rates consistent with industry data for Alloy 600
) No crack extension in Alloy 52 at high stress intensity and extended times 24
Recent Industry Experience with Alloy_052/152
- . DC Cook Inlay Repair
- VC Summer Butt Weld Repair o:Canopy Seal Weld Overlay Repairs
- o. BWR Nozzle to Safe End Weld Overlay Repairs o*North Anna Overlay Repairs
- ANO-1 Repair in 1 R16 To Date, No Problems Have Been Reported 25
WeldRepair Design_(cont.)
- oSummary
> Material Demonstrated to be Resistant to PWSCC Initiation and Growth
> Repair Qualified to Meet All Pertinent ASME Code Section III & XI Criteria 26
Repair Assurance for Not Having Leak Paths to Annulus
Repair Assurance for Not Having Leak Paths to Annulus
- -*Evaluation of Leak Paths to Annulus
> Boron from above RV nozzle annulus
) Flowpath through ID of nozzle to annulus
> Flowpath through 052 weld material
) Flowpath around 052 weld repair 28
Boron from Above RV Nozzle Annulus
- oGeometry and Temperature Result in Low Probability of Maintaining a Wetted Surface
- o. Not Considered to be a Credible Condition 29
Flowpath Through ID of Nozzle to Annulus
- .*Volumetric Exam of Nozzles Performed
- . No Indications will be Left in Service o*-Adequate Assurance is Being Provided to Prevent Leakage through ID of Nozzle 30
Flowpath Through 052 Weld Material
- -*Previously Discussed the Integrity of the 052 Weld Material
- . Not considered to be a Credible Leak Path 31
Flowpath Around 052 Weld Repair o:* Existing 082/182 Weld Boundary Will Be Clearly Identified
- Lessons Learned on Ensuring Adequate Coverage of 082/182 Material with Repair Weld Included in Repair Procedures
- .Repair Process Will Ensure Integrity of Weld Repair 32
Safety Perspective Mike Krupa Director, Nuclear Safety Assurance
Safety Perspective
.**Repair Plans will Remove All Mechanistic Failures that Can Create Leak Paths
- .Repair meets ASME Section Xl Code Requirements
.**Repair Process Has Incorporated Industry Lessons Learned
- -Boundary of 082/182 and SS Clad will be Defined
- -Appendix B Program will Ensure Proper Weld Application and Quality Control 34
Safety Perspective
- Annulus Will Be Isolated from PWSCC Environment o*Industry/MRP Analyses Have Demonstrated that Alloy 600 Will Not Become a Safety Concern when Properly Managed 35
L4;.A; 4- -
Concluding Remarks 36
Backup CRDM Nozzle Slides Nozzle 56 UT ub Scans 9
Lower Weld Toe 38
UT Graphic of 1R17 Nozzle 56 IUp peJ- Ield "1e W h I Circumference (degrees) 39