ML052760163
| ML052760163 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 09/28/2005 |
| From: | Vanderheyden G Constellation Energy Group |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| TAC MA4647, TAC MA4648 | |
| Download: ML052760163 (16) | |
Text
George Vanderheyden 1650 Calvert Cliffs Parkway Vice President Lusby, Maryland 20657 Calvert Cliffs Nuclear Power Plant 410.495.4455 Constellation Generation Group, LLC 410.495.3500 Fax I Constellation Energy September 28, 2005 U. S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION: Document Control Desk
SUBJECT:
Calvert Cliffs Nuclear Power Plant UnitNos. I & 2; DocketNos. 50-317 & 50-318 ASME Section XI Relief Request to Use Weld Overlay and Associated Alternative Techniques
REFERENCE:
(a) Letter from Ms. M. Gamberoni (NRC) to Mr. C. H. Cruse (BGE), dated April 5, 2000, Safety Evaluation of Proposed Alternate American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code)
Section XI, 1998 Edition for the Third 10-Year Inspection Interval -
Calvert Cliffs Nuclear Power Plant, Unit Nos. I and 2 (TAC Nos.
MA4647 and MA4648)
Pursuant to 10 CFR 50.55a(a)(3)(i), Calvert Cliffs Nuclear Power Plant, Inc. (CCNPP) hereby proposes alternatives to the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Code) requirements concerning repair/replacement activities for pressure retaining welds subject to Article IWA-4000 in Section XI for the Third Ten-Year Inservice Inspection interval.
Paragraph 50.55a(a)(3)(i) allows the use of alternatives to the requirements of Paragraph 50.55a(g),
which provide an acceptable level of quality and safety, when authorized by the Director of the Office of Nuclear Reactor Regulation.
The Third Ten-Year Inservice Inspection Program Plan for Calvert Cliffs Units I and 2 meets the requirements of the 1998 Edition, no Addenda, of Section XI of the ASME Code (except for Subsections IWE and IWL), as approved by Nuclear Regulatory Commission (NRC) letter (Reference a).
RELIEF REQUEST Article IWA-4000 of ASME Code,Section XI, and NRC approved Code Cases N-504-2 and N-638 contain the requirements for structural weld overlay repair activities for unacceptable indications in welded nozzles. Appendix VIII, Supplement 11 of Section XI contains ultrasonic examination requirements for the completed structural weld overlay repair. In lieu of these ASME Code requirements, CCNPP proposes to use alternative techniques for full structural weld overlay repair, and the examination of dissimilar metal welds with unacceptable indications in existing Alloy 82/182 welds.
Relief requests have been previously approved for Calvert Cliffs Unit 2 and other licensees, including
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Document Control Desk September 28, 2005 Page 2 AmerGen Energy Company for its Three Mile Island Nuclear Station, Unit I on July 21, 2004 for most of the alternative techniques proposed in this request. The detailed relief request and the justification are provided in Attachment (1).
SCHEDULE The structural weld overlay is intended as a contingency repair for any flaws identified during examination of dissimilar metal welds in the upcoming Calvert Cliffs Unit I Spring 2006 refueling outage (scheduled to begin in late February 2006) and the remainder of the third ten year inservice inspection interval for Units 1 and 2. We request that the NRC review and approve our proposed alternative for use during this outage and subsequent third interval outages.
Should you have questions regarding this matter, please contact Mr. L. S. Larragoite at (410) 495-4922.
VeVly urs, GV/MJY/bjd
Attachment:
(1) Relief Request To Use Alternative Techniques for Repair and Examination of Unacceptable Indications in Welded Nozzles cc: P. D. Milano, NRC Resident Inspector, NRC S. J. Collins, NRC R. I. McLean, DNR
ATTACHMENT (1)
RELIEF REQUEST TO USE ALTERNATIVE TECHNIQUES FOR REPAIR AND EXAMINATION OF UNACCEPTABLE INDICATIONS IN WELDED NOZZLES Calvert Cliffs Nuclear Power Plant, Inc.
September 28,2005
ATTACHMENT (1)
RELIEF REQUEST TO USE ALTERNATIVE TECHNIQUES FOR REPAIR AND EXAMINATION OF UNACCEPTABLE INDICATIONS IN WELDED NOZZLES COMPONENT FOR WHICH RELIEF IS REOUESTED:
Class I dissimilar metal welds, with unacceptable indications attributed to primary water stress corrosion cracking (PWSCC) in existing Alloy 82/182 welds. These welds may include:
UNIT I DM WELD POPULATION Designator/ID Weld Nozzle Location Function Base Material
___ __ ___ __ __ M aterial Size _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
102300/30-RC-I IA-W7 .182/82 30" 1lA RCP Inlet RCS Loop A516-70/A351-CF8M 102450/30-RC-1 IA-WlO 182/82 30" 1IA RCP Outlet RCS Loop A516-70/A351-CF8M 104550/30-RC-1 1B-W7 182/82 30" 1lB RCP Inlet RCS Loop A516-70/A351-CF8M 104700/30-RC-I IB-W I0- 182/82 30" I IB RCP Outlet RCS Loop A516-70/A351-CF8M 107450/30-RC-12A-W7 182/82 30" 12A RCP Inlet RCS Loop A516-70/A351-CF8M 107600/30-RC-12A-WIO 182/82 30" 12A RCP Outlet RCS Loop A516-70/A351-CF8M 109600/30-RC-12B-W7 182/82 30" 12B RCP Inlet RCS Loop A516-70/A351-CF8M 109750/30-RC-12B-WIO 182/82 30" 12B RCP Outlet RCS Loop A516-70/A351-CF8M 110450/12-PSL-WI 182/82 12" Bottom Head of PZR PZR Surge SA508-C12/ SA351-CF8M 111100/12-PSL-W13 182/82 12" Top of 11 Hot Leg PZR Surge A105-GrI/ A351-CF8M 113150/12-SC-1004-WI 182/82 12" Bottom of 12 Hot Leg Shutdown Cooling A105-GrlI/A351-CF8M 114350/12-SI-1009-W16 182/82 12" Top of I IA Cold Leg Safety Injection A182-F-1/ A351-CF8M 115200/12-SI-1010-W14 -182/82 12" Top of 1lB Cold Leg Safety Injection A182-F-V A351-CF8M 116000/12-SI-101 1-W13 182/82 12" Top of 12A Cold Leg Safety Injection A182-F-I/ A351-CF8M 116750/12-SI-1012-W13 182/82 12" Top of 12B Cold Leg Safety Injection A182-F-I/ A351-CF8M 118500/4-PS-1003-W6 182/82 4" Top Head of PZR PZR Spray SA508-C12/SA-182-F316 118550/3-PS-1001-WI 182/82 3" Top of 1IA Cold Leg PZR Spray A105-Grll/A-182-TP316 120350/3-PS-1002-WI 182/82 3" Top of I lB Cold Leg PZR Spray A105-GrIl/A-182-TP316 123100/4-SR-1005-WI 182/82 4" Top of PZR PZR Relief SA508-C12/SA-182-F316 123450/4-SR-1006-WI 182/82 . 4" Top of PZR PZR Relief SA508-C12/SA-182-F316 125050/2-LD-1004-WI 182/82 2" Bottom of 12A Cold Leg Letdown/Drain A105-GrlI/A-182-TP316 128900/2-CV-1004-WI9 182/82 2" 12B Cold Leg Charging Inlet A105-GrIIIA-I82-TP316 130450/2-CV-1005-W29 182/82 2" l A Cold Leg Charging Inlet A105-GrIlA-182-TP316 131200/2-DR-1003-W1 182/82 2" Bottom of I IA Cold Leg Loop Drain A105-GrIl/A-182-TP316 131500/2-DR-1004-W1 182/82 2" Bottom of 1B Cold Leg Loop Drain A105-GrII/A-182-TP316 132150/2-DR-1006-WI 182/82 2" Bottom of 12B Cold Leg Loop Drain A105-GrII/A-182-TP316 1
ATTACHMENT (1)
RELIEF REQUEST TO USE ALTERNATIVE TECHNIQUES FOR REPAIR AND EXAMINATION OF UNACCEPTABLE INDICATIONS IN WELDED NOZZLES UNIT 1 DM WELD POPULATION Designator/ID Weld Nozzle I Location Function Base Material
______________________________ Material Size - otmo IHtLg Lo ri 132450/2-DR-1007-WI 182/82 2" Bottom of 11 Hot Leg Loop Drain A105-GrIVA-182-TP316 UNIT 2 DM WELD POPULATION Designator/ID Weld Nozzle Location Function Base Material
____ ___ ___ ____ A___ _. 182/82.Material Size 21A___Ile___Lop ________
109280/30-RC-21A-W7 182/82 30" 21A RCP Inlet RCS Loop A516-70/A351-CF8M 109310/30-RC-21A-WIO 182/82 30" 21A RCP Outlet RCS Loop A516-70/A351-CF8M 110280/30-RC-21B-W7 182/82 30" 21B RCP Inlet RCS Loop A516-70/A351-CF8M 110310/30-RC-21B-WIO 182/82 30" 21B RCP Outlet RCS Loop A516-70/A351-CF8M 11 1280/30-RC-22A-W7 182/82 30" 22A RCP Inlet RCS Loop A516-70/A351-CF8M 11 1310/30-RC-22A-WIO 182/82 30" 22A RCP Outlet RCS Loop A516-70/A351-CF8M 112280/30-RC-22B-W7 182/82 30" 22B RCP Inlet RCS Loop A516-70/A351-CF8M 112310/30-RC-22B-WIO 182/82. 30"9 22B RCP Outlet RCS Loop A5 16-70/A3 51-CF8M 113010/12-PSL-Wl 182/82 12" Bottom Head of PZR PZR Surge SA508-C12/. SA351-CF8M 113130/12-PSL-W13 182/82 12" Top of 21 Hot Leg PZR Surge A105-GrIlVA351-CF8M 114900/12-SC-2004-WI -182/82 12" Bottom of 22 Hot Leg Shutdown Cooling A105-GrII A351-CF8M 115140/12-SI-2009-W15 182/82 12" Top of 21B Cold Leg Safety Injection A182-F-1/A351-CF8M 116190/12-SI-2010-W13 182/82 12" Top of 21A Cold Leg Safety Injection A182-F-1/ A351-CF8M 117120/12-SI-201 1-W13 182/82 12". Top of 22B Cold Leg Safety Injection A182-F-1/ A351-CF8M 11 8120/12-SI-2012-W13 182/82 12" Top of 22A Cold Leg Safety Injection A182-F-1/ A351-CF8M 136090/4-PS-2003-W8 182/82 4" Top Head of PZR PZR Spray SA508-C12/SA-182-F316 137010/3-PS-2001-WI 182/82 3" Top of 21A Cold Leg PZR Spray A105-Grll/A-182-TP316 138010/3-PS-2002-WI 182/82 3" Top of 21B Cold Leg PZR Spray A105-GrII/A-182-TP316 141000/4-SR-2005-W1 182/82 4" Top of PZR PZR Relief SA508-C12/SA-1 82-F316 142000/4-SR-2006-WI 182/82 4" Top of PZR PZR Relief SA508-C12/SA-182-F316.
152440/2-CV-2005-W30 182/82 2" 21A Cold Leg Charging Inlet A105-GrIIA-182-TP316 156530/2-CV-2021-W34 182/82 2" 22B Cold Leg Charging Inlet A105-GrlVA-182-TP316 157010/2-DR-2003-WI 182/82 2" Bottom of 21A Cold Leg Loop Drain A105-GrIIIA-182-TP316 158010/2-DR-2004-W1 182/82 2" Bottom of 21B Cold Leg Loop Drain A105-GrIVA-182-TP316 160010/2-DR-2006-W1 182/82 2" Bottom of 22B Cold Leg Loop Drain A105-GrIIVA-182-TP316 2
ATTACHMENT (1)
RELIEF REQUEST TO USE ALTERNATIVE TECHNIQUES FOR REPAIR AND EXAMINATION OF UNACCEPTABLE INDICATIONS IN WELDED NOZZLES CODE REQUIREMENTS FOR WHICH RELIEF IS REQUESTED:
The 1998 Edition, no Addenda, of American Society of Mechanical Engineers (ASME)Section XI, Article IWA-4000 and Appendix VIII, Supplement 11 and Nuclear Regulatory Commission (NRC) approved Code Cases N-504-2 and N-638. Tables 1-4 provide the specific requirements that are included in this relief request.
PROPOSED ALTERNATIVE AND SUPPORTING INFORMATION:
For dissimilar-metal welds with unacceptable indications in existing Alloy 82/182 welds attributed to PWSCC, a full structural weld overlay modification is proposed. The nozzle material is ferritic steel (either PI or P3 depending on the nozzle). The pipe is austenitic stainless steel (P8). The existing weld filler material is Alloy 82/182 (F43 equivalent to P43). The overlay will be designed as a full structural overlay in accordance with ASME Section XI Code Case N-504-2. The temperbead welding technique will be implemented in accordance with ASME Section XI Code Case N-638 for that portion of the overlay over ferritic base material for which the Construction Code required post-weld heat treatment.
This full structural overlay will satisfy all the structural design requirements of the pipe as if the pipe were not there. The structural weld overlay (weld reinforcement) will completely cover the existing Alloy 82/182 weld metal and extend onto the ferritic and austenitic stainless steel material on each end.
Tables 1, 2, 3, and 4 provide the detailed requirements, the proposed alternatives, and the bases for the alternatives. The modification will be performed as a repair/replacement activity in compliance with Article IWA-4000 of the 1998 Edition, no Addenda, of ASME Section XI as modified and supplemented in Table 1. Certain requirements of IWA-4000, shown in Table 1, will be accomplished using the methodology of Code Case N-504-2 (Alternative Rules for Repairs of Classes 1, 2, and 3 Austenitic Stainless Steel Piping) modified as shown in Table 2, and the methodology of Code Case N-638 [Similar and Dissimilar Metal Welding using Ambient Temperature Machine GTAW (Gas Tungsten Arc Welding) Temperbead Technique] modified as shown in Table 3. Ultrasonic examination of the completed structural overlay will be accomplished in accordance with ASME Section XI, Appendix VIII, Supplement II modified to comply with the Performance Demonstration Initiative (PDI) program as shown in Table 4. Any applicable requirements not modified by Tables 1, 2, 3, or 4 will be met as described in IWA-4000, Appendix VIII Supplement 11, and Code Cases N-504-2 and N-638.
Code Case N-504-2 was approved for generic use in Regulatory Guide 1.147, Revision 13, and was developed for austenitic stainless steel material. An alternate application for nickel based and ferritic materials is proposed due to the specific configuration of the subject weldments. Therefore, Calvert Cliffs intends to follow the methodology of Code Case N-504-2, except for the differences identified in Table 2.
Code Case N-638 was approved for generic use in Regulatory Guide 1.147, Revision 13, and was developed for similar and dissimilar metal welding using ambient temperature machine GTAW temperbead technique. Calvert Cliffs intends to follow the methodology of Code Case N-638 for any welding on ferritic or ferritic/austenitic interfaces where the Construction Code required post-weld heat treatment, except for the differences identified in Table 3.
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ATTACHMENT (i)
RELIEF REQUEST TO USE ALTERNATIVE TECHNIQUES FOR REPAIR AND EXAMINATION OF UNACCEPTABLE INDICATIONS IN WELDED NOZZLES CONCLUSION:
Calvert Cliffs believes the proposed alternatives to Article IWA-4000, Appendix VIII, Supplement 11, and NRC approved Code Cases N-504-2 and N-638, as described in this request, provide an acceptable level of quality and safety.
Table 1 Modifications to IWA4000 I
IWA-4000 Differences/Basis for Relief IWA-4610(a) The area to be welded plus a band around Relief. In lieu of weld-attached thermocouples and the area of at least 1-112 times the component thickness recording instruments, we will monitor the process or 5 in. (127 mm), whichever is less, shall be preheated temperatures with contact pyrometers and provide a and maintained at a minimum temperature of 350 0F manual record of the process temperatures.
(1771C) for the SMAW [shielded metal arc welding]
process and 3001F (149 0C) for the GTAW process during welding. The maximum interpass temperature shall be 450'F (232 0 C). Thermocouples and recording instruments shall be used to monitor the process temperatures. Their attachment and removal shall be in accordance with Section III.
Code Case N-638 4.0(c) Areas from which weld-attached thermocouples have been removed shall be ground and examined using a surface examination method.
Table 2 Modifications to Code Case N-504-2 Code Case N-504-2 Differences/Basis for Relief Reply: It is the opinion of the Committee that, in Relief. We propose to apply Code Case N-504-2 to the lieu of the requirements of IWA-4120 in Editions ferritic (Pl or P3) and nickel alloy (F43/P43) base material and Addenda up to and including the 1989 Edition as well as the austenitic stainless steel (PS) base material.
with the 1990 Addenda, in IWA-4170(b) in the Code -Case N-504-2 is accepted without restriction in the 1989 Edition with the 1991 Addenda up to and current NRC Regulatory Guide 1.147. The base material including the 1995 Edition, and in IWA-4410 in the will be ferritic material (P1 or P3) with existing nickel alloy 1995 Edition with the 1995 Addenda and later weld metal (F43/P43) to which an austenitic stainless steel Editions and Addenda, defect in austenitic stainless (P8) pipe is welded. Industry operational experience has steel piping may be reduced to a flaw of acceptable shown that PWSCC in Alloy 82/182 will blunt at the size in accordance with IWB-3640 from the 1983 interface with stainless steel base metal, ferritic' base metal, Edition with the Winter 1985 Addenda, or later or Alloy 52/52M/152 weld metal. The weld overlay will put Editions and Addenda, by deposition of weld compressive stress around the weldment, thus impeding reinforcement (weld overlay) on the outside surface growth of any existing crack and will fulfill all structural of the pipe, provided the following requirements are requirements, independent of the existing weld.
met:
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ATTACHMENT (1)
RELIEF REQUEST TO USE ALTERNATIVE TECHNIQUES FOR REPAIR AND EXAMINATION OF UNACCEPTABLE INDICATIONS IN WELDED NOZZLES Table 2 Modifications to Code Case N-504-2 Code Case N-504-2 Differences/Basis for Relief (b) Reinforcement weld metal shall be low carbon Relief. In lieu of austenitic stainless steel filler material, the (0.035% max.) austenitic stainless steel applied reinforcement weld metal will be a nickel alloy. The weld 3600 around the circumference of the pipe, and shall metal will be either ERNiCrFe-7 (Alloy 52, UNS N06052) or be deposited in accordance with a qualified welding ERNiCrFe-7A (Alloy 52M, UNS N06054). ENiCrFe-7 may procedure specification identified in the Repair be used to SMAW seal weld the initial base metal surfaces or Program. to perform repair on the weld reinforcement. These weld metals are assigned F43 by ASME per Code Case 2142-2.
The requirements of ASME Section III, NB-2400 will be applied to all filler material.
The chromium content of Alloy 52M is 28-31.5%, identical to that of Alloy 52. The main difference in Alloy 52 is a higher Niobium content (0.5-1%). The difference in chemical composition between Alloy 52 and Alloy 52M improves weldability of the material, pinning the grain boundaries preventing separation between grains, and hot tearing during weld puddle solidification. This filler material was selected for its improved resistance to PWSCC.
Alloys 52, 52M, and 152 all contain about 30% chromium that imparts excellent corrosion resistance. The existing Alloy 82/182 weld and the Alloy 52/52M overlay are austenitic and have ductile properties and toughness similar to austenitic stainless steel piping welds at pressurized water reactor operating temperature. These filler materials are suitable for welding over the ferritic nozzle, Alloy 82/182 weld and the austenitic stainless steel piping.
(NOTE: ERNiCrFe-7 and ENiCrFe-7 are assigned F number 43 by the 2004 Edition of ASME Section IX.
ERNiCrFe-7A (UNS N06054) is assigned F number 43 by Boiler and Pressure Vessel Code Case 2142-2.)
(e) The weld reinforcement shall consist of a Relief. Delta ferrite (FN) measurements will not be minimum of two weld layers having as-deposited performed for this overlay because welds of delta ferrite content of at least 7.5 FN. The first Alloy 52/52M152 are 100% austenitic and contain no delta layer of weld metal with delta ferrite content of least ferrite due to the high nickel composition (approximately 7.5 FN shall constitute the first layer of the weld 60% nickel).
reinforcement design thickness. Alternatively, first layers of at least 5 FN may be acceptable based on evaluation.
(I) All other applicable requirements of IWA4000 Relief. In lieu of the ultrasonic examination acceptance and IWB-4000, IWC-4000, or IWD-4000 shall be criteria of the Construction Code, the following acceptance met. criteria will be used.
Planar indication(s) detected during ultrasonic examination will be evaluated in accordance with Table IWB-3514-2 of ASME Section XI.
Laminar indication(s) detected during ultrasonic examination will be evaluated in accordance with Table IWB-3514-3 of ASME Section XI, and the following:
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ATTACHMENT (1)
RELIEF REQUEST TO USE ALTERNATIVE TECHNIQUES FOR REPAIR AND EXAMINATION OF UNACCEPTABLE INDICATIONS IN WELDED NOZZLES Table 2 Modifications to Code Case N-504-2 Code Case N-504-2 Differences/Basis for Relief
- Laminar indications not located at the pipe/overlay interface may require evaluation to IWB-3514-2.
- Laminar indications shall permit examination of at least 90% of the examination volume and shall not interfere with interrogation of the base material examination volume.
- The size of the lamination as it relates to the total size of the overlay.
- The above acceptance criteria will be used for subsequent inservice inspection of the weld overlay(s).
Table 3 Modifications to Code Case N-638 Code Case N-638 Differences/Basis for Relief Reply: It is the opinion of the Committee that repair to Relief. We propose to weld on non water backed as P-No. 1, 3, except SA-302 Grade B, 12A, 12B, and 12C well as water backed components. The phrase "when material and their associated welds and P No. 8 or it is impractical, for operational or radiological P No.43 material to P-Nos. 1, 3, except SA-302 Grade B, reasons, to drain the component" limits application to 12A, 12B, and 12C material and their associated welds, water backed components. We believe restriction to may be made by the automatic or machine GTAW water backed components was an oversight in Code temperbead technique without the specified preheat or Case N-638 since Code Case N-638-1 permits non postweld heat treatment of the Construction Code, when it water backed applications (with no other change over is impractical, for operational or radiological reasons, to Code Case N-638). Code Case N-638-1 is not yet drain the component, and without the NDE requirements of approved for generic use in NRC Regulatory Guide the Construction Code, provided the requirements of 1.147. Mockups of the structural overlay will be paragraphs 1.0 through 5.0, and all other requirements of performed on both water backed and non water IWA-4000, are met. backed samples to validate parameters for both situations.
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ATTACHMENT (1)
RELIEF REQUEST TO USE ALTERNATIVE TECHNIQUES FOR REPAIR AND EXAMINATION OF UNACCEPTABLE INDICATIONS IN WELDED NOZZLES Table 3 Modifications to Code Case N-638 Code Case N-638 Differences/Basis for Relief 1.0(a) The maximum area of an individual weld based on Relie. We propose to exceed the 100 in2 limitation the finished surface shall be 100 in2, and the depth of the when necessary.
weld shall not be greater than one-half of the ferritic base Application of Code Case N-638 will be on the ferritic metal thickness. portion of the base material extending onto the existing F43 buttering a minimum of 1/8 inch [to satisfy 1.0(b)]. Depending on the diameter of the nozzle to be overlaid and the axial extent of the overlay onto the ferritic material, the 100 in2 limit may be exceeded. Additional axial extent onto the ferritic material may be necessary to facilitate ultrasonic examination and/or to ensure a smooth final nozzle contour. Studies by Structural Integrity (SI), Electric Power Research Institute (EPRI), and others indicate the 100 in2. limitation is arbitrary and repair areas to at least 500 in2 have no adverse effect.
Appendix VIII of Section XI cannot be used for the structural weld overlay required NDE. Relief is requested to use the PDI program implementation of Appendix VIII. A detailed comparison of Appendix VIII and PDI requirements is summarized below.
Relief is requested to allow closer spacing of flaws provided they do not interfere with detection or discrimination. The specimens used to date for qualification to the Tri-party (NRC/B WROG/EPRI) agreement have a flaw population density greater than allowed by current Code requirements. These samples have been used successfully for all previous qualifications under the Tri-party agreement program. To facilitate their use and provide continuity from the Tri-party agreement program to Supplement 11, the PDI program has merged the Tri-party test specimens into their weld overlay program.
Table 4 Modifications to ASME Section 'IAppendix VIII, Supplement 11 SUPPLEMENT 11-QUALIFICATION PDI PROGRAM:
REQUIREMENTS FOR FULL STRUCTURAL The Proposed Alternative to OVERLAID WROUGHT AUSTENITIC PIPING Supplement 11 Requirements WELDS 1.0 SPECIMEN REQUIREMENTS 1.1 General. The specimen set shall conform to the following requirements.
(b) The specimen set shall consist of at least three (b) .. The specimen set shall include specimens with specimens having different nominal pipe diameters and overlays not thicker than 0.1 in. more than the minimum overlay thicknesses. They shall include the minimum thickness, nor thinner than 0.25 in. of the maximum and maximum nominal pipe diameters for which the nominal overlay thickness for which the examination examination procedure is applicable. Pipe diameters' procedure is applicable.
within a range of 0.9 to 1.5 times a nominal diameter To avoid confusion, the overlay thickness tolerance shall be considered equivalent. If the procedure is
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ATTACHMENT (1)
RELIEF REQUEST TO USE ALTERNATIVE TECHNIQUES FOR REPAIR AND EXAMINATION OF UNACCEPTABLE INDICATIONS IN WELDED NOZZLES Table 4 Modifications to ASME Section XI, Appendix VIII, Supplement 11 SUPPLEMENT I1-QUALIFICATION PDI PROGRAM:
REQUIREMENTS FOR FULL STRUCTURAL The Proposed Alternative to OVERLAID WROUGHT AUSTENITIC PIPING Supplement 11 Requirements WELDS applicable to pipe diameters of 24 in. or larger, the contained in the last sentence was reworded and the specimen set must include at least one specimen 24 in. phrase "and the remainder shall be alternativeflaws" or larger but need not include the maximum diameter. was added to the next to last sentence in The specimen set must include at least one specimen paragraph1.l(d)(l).
with overlay thickness within -0.1 in. to +0.25 in. of the maximum nominal overlay thickness for which the procedure is applicable.
(d) Flaw Conditions (1) Base metal flaws. All flaws must be cracks in or (1) ...must be in or... intentional overlay fabrication near the butt weld heat-affected zone, open to the inside flaws shall not interfere with ultrasonic detection or surface, and extending at least 75% through the base characterization of the base metal flaws. Specimens metal wall. Flaws may extend 100% through the base containing intergranular stress corrosion cracking shall metal and into the overlay material; in this case, be used when available. At least 70% of the flaws in the intentional overlay fabrication flaws shall not interfere detection and sizing tests shall be cracks and the with ultrasonic detection or characterization of the remainder shall be alternative flaws. Alternative flaw cracking. Specimens containing intergranular stress mechanisms, if used, shall provide crack-like reflective corrosion cracking shall be used when available. characteristics and shall be limited by the following:
(a) The use of alternative flaws shall be limited to when the implantation of cracks produces spurious reflectors that are uncharacteristic of actual flaws.
(b) Flaws shall be semi elliptical with a tip width of less than or equal to 0.002 inches.
This paragraph requires that all base metal flaws be cracks. Implanting a crack requires excavation of the base material on at least one side of theflaw. While this may be satisfactory for ferritic materials, it does not produce a useable axial flaw in austenitic materials because the sound beam, which normally passes only through base material, must now travel through weld material on at least one side, producing an unrealistic flaw response. To resolve this issue, the PDI program revised this paragraphto allow use of alternativeflaw mechanisms under controlled conditions. For example, alternativeflawsshall be limited to when implantation of cracks precludes obtaining an effective ultrasonic response,flaws shall be semi ellipticalwith a tip width of less than or equal to 0.002 inches, and at least 70% of the flaws in the detection and sizing test shall be cracks and the remaindershall be alternativeflavs.
To avoid. confusion, the overlay thickness tolerance contained in paragraph 1.I(b) last sentence, was reworded and the phrase "and the remainder shall be alternativeflaws" was addedto the next to last sentence.
Paragraph I.13(d)() includes the statement that 8
ATTACHMENT (1)
RELIEF REQUEST TO USE ALTERNATIVE TECHNIQUES FOR REPAIR AND EXAMINATION OF UNACCEPTABLE INDICATIONS IN WELDED NOZZLES Table 4 Modifications to ASME Section ' Appendix VIII, Supplement 11 SUPPLEMENT 11- QUALIFICATION PDI PROGRAM:
REQUIREMENTS FOR FULL STRUCTURAL The Proposed Alternative to OVERLAID WROUGHT AUSTENITIC PIPING Supplement 11 Requirements WELDS intentional overlay fabricationflaws shall not interfere with ultrasonicdetection or characterizationof the base metalflaws.
(e) Detection Specimens (1) At least 20% but less than 40% of the flaws shall be (1) At least 20% but less than 40% of the base metal oriented within +200 of the pipe axial direction. The flaws shall be oriented within +200 of the pipe axial remainder shall be oriented circumferentially. Flaws direction. The remainder shall be oriented shall not be open to any surface to which the candidate circumferentially. Flaws shall not be open to any surface has physical or visual access. The rules of IWA-3300 to which the candidate has physical or visual access.
shall be used to determine whether closely spaced flaws The requirementfor axially oriented overlayfabrication should be treated as single or multiple flaws'. flawls was excluded from the PDI Program as an improbable scenario. Weld overlays are typically appliedusing automatedGTA W techniques with thefiller metal applied in a circumferential direction. Because resultantfabrication induced discontinuities would also be expected to have major dimensions oriented in the circumferentialdirection axial overlayfabricationflavs are unrealistic.
The requirementfor using IIWA-3300 for proximityflaw evaluation was excluded. Instead, indications will be sized based on their individual merits.
(2) Specimens shall be divided into base and over-lay (2) Specimens shall be divided into base metal and grading units. Each specimen shall contain one or both overlay fabrication grading units. Each specimen shall types of grading units. contain one or both types of grading units. Flaws shall not interfere with ultrasonic detection or characterization of other flaws.
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ATTACHMENT (1)
RELIEF REQUEST TO USE ALTERNATIVE TECHNIQUES FOR REPAIR AND EXAMINATION OF UNACCEPTABLE INDICATIONS IN WELDED NOZZLES Table 4 Modifications to ASME Section XI Appendix VIII Supplement 11 SUPPLEMENT 11 -QUALIFICATION PDI PROGRAM:
REQUIREMENTS FOR FULL STRUCTURAL The Proposed Alternative to OVERLAID WROUGHT AUSTENITIC PIPING Supplement 11 Requirements WELDS (a)(J)A base grading unit shall include at least 3 in. of (a)(l) A base metal grading unit includes the overlay the length of the overlaid weld. The base grading unit material and the outer 25% of the original overlaid weld.
includes the outer 25% of the overlaid weld and base The base metal grading unit shall extend metal on both sides. The base grading unit shall not circumferentially for at least I in. and shall start at the include the inner 75% of the overlaid weld and base weld centerline and be wide enough in the axial direction metal overlay material, or base metal-to-overlay to encompass one half of the original weld crown and a interface. minimum of 0.50" of the adjacent base material.
The phrase "and base metal on both sides," was inadvertently included in the descriptionof a base metal grading unit. The PD! program intentionally excludes this requirement because some of the qualification samples include flaws on both sides of the weld. To avoid confusion several instances of the term "cracks" or "cracking" were changed to the term 'flaws" because of the use of alternativeflawv mechanisms.
Modified to require that a base metal grading unit include at least I in. of the length of the overlaid wield, ratherthan 3 inches.
(a)(2) When base metal cracking penetrates into the (a)(2) When base metal flaws penetrate into the overlay overlay material, the base grading unit shall include the material, the base metal grading unit shall not be used as overlay metal within I in. of the crack location. This part of any overlay fabrication grading unit.
portion of the overlay material shall not be used as part of any overlay grading unit.
(a)(3) When a base grading unit is designed to be (a)(3) Sufficient unflawed overlaid weld and base metal unflawed, at least 1 in. of unflawed overlaid weld and shall exist on all sides of the grading unit to preclude base metal shall exist on either side of the base grading interfering reflections from adjacent flaws.
unit. The segment of weld length used in one base Modifed to require sufficient unflawed overlaid weld grading unit shall not be used in another base grading and base metal to exist on all sides of the grading unit to unit. Base grading units need not be uniformly spaced preclude interfering reflections from adjacent flaws, around the specimen. ratherthan the I inch requirement.
(b)(l) An overlay grading unit shall include the overlay (b)(l) An overlay fabrication grading unit shall include material and the base metal-to-overlay interface of at the overlay material and the base metal-to-overlay least 6 in2. The overlay grading unit shall be interface for a length of at least I in.
rectangular, with minimum dimensions of 2 in. Modified to define an overlayfabricationgrading unit as including the overlay material and the base metal-to-overlay interfacefor a length ofat least I in, ratherthan the 6 in2 requirement 10
ATTACHMENT (1)
RELIEF REQUEST TO USE ALTERNATIVE TECHNIQUES FOR REPAIR AND EXAMINATION OF UNACCEPTABLE INDICATIONS IN WELDED NOZZLES Table 4 Modifications to ASME Section XI, Appendix VIII, Supplement 11 SUPPLEMENT 11 -QUALIFICATION PDI PROGRAM:
REQUIREMENTS FOR FULL STRUCTURAL The Proposed Alternative to OVERLAID WROUGHT AUSTENITIC PIPING Supplement 11 Requirements WELDS (b)(2) An overlay grading unit designed to be unflawed (b)(2) Overlay fabrication grading units designed to be shall be surrounded by unflawed overlay~material and unflawed shall be separated by unflawed overlay material unflawed base metal-to-overlay interface for at least and unflawed base metal-to-overlay interface for at least I in. around its entire perimeter. The specific area used 1 in. at both ends. Sufficient unflawed overlaid weld and in one overlay grading unit shall not be used in another base metal shall exist on both sides of the overlay overlay grading unit. Overlay grading units need not be fabrication grading unit to preclude interfering reflections spaced uniformly about the specimen. from adjacent flaws. The specific area used in one overlay fabrication grading unit shall not be used in another overlay fabrication grading unit. Overlay fabrication grading units need not be spaced uniformly about the specimen.
Paragraph1.1(e)(2)(b)(2) states that overlayfabrication gradingunits designed to be unflawedshall be separated by unflawed overlay materialand unflaw ed base metal-to-overlay interfacefor at least I in. at both ends, rather than aroundits entireperimeter.
(b)(3) Detection sets shall be selected from ...base metal grading units, ten unflawed base metal Table VIII-S2-1. The minimum detection sample set is grading units, five flawed overlay fabrication grading five flawed base grading units, ten unflawed base units, and ten unflawed overlay fabrication grading units.
grading units, five flawed overlay grading units, and ten For each type of grading unit, the set shall contain at least unflawed overlay grading units. For each type of twice as many unflawed as flawed grading units. For grading unit, the set shall contain at least twice as many initial procedure qualification, detection sets shall unflawed as flawed grading units. include the equivalent of three personnel qualification sets. To qualify new values of essential variables, at least one personnel qualification set is required.
(a)Sizing Specimen (1) The minimum number of flaws shall be ten. At least (I) The .... least 40% of the flaws shall be open to the 30% of the flaws shall be overlay fabrication flaws. At inside surface. Sizing sets shall contain a distribution of least 40% of the flaws shall be cracks open to the inside flaw dimensions to assess sizing capabilities. For initial surface. procedure qualification, sizing sets shall include the equivalent of three personnel qualification sets. To qualify new values of essential variables, at least one personnel qualification set is required.
(3) Base metal cracking used., for length sizing (3)Base metal flaws used ... circumferentially.
demonstrations shall be oriented circumferentially.
(4) Depth sizing specimen sets shall include at least two (4) Depth sizing specimen sets shall include at least two distinct locations where cracking in the base metal distinct locations where a base metal flaw extends into extends into the overlay material by at least 0.1 in. in the the overlay material by at least 0.1 in. in the through-wall through-wall direction. direction.
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ATTACHMENT (1)
RELIEF REQUEST TO USE ALTERNATIVE TECHNIQUES FOR REPAIR AND EXAMINATION OF UNACCEPTABLE INDICATIONS IN WELDED NOZZLES Table 4 Modifications to ASME Section 'I, Appendix VIII, Supplement 11 SUPPLEMENT 11 - QUALIFICATION PDI PROGRAM:
REQUIREMENTS FOR FULL STRUCTURAL The Proposed Alternative to OVERLAID WROUGHT AUSTENITIC PIPING Supplement 11 Requirements WELDS 2.0 CONDUCT OF PERFORMANCE DEMONSTRATION The specimen inside surface and identification shall be The specimen ..... prohibited. The overlay fabrication concealed from the candidate. All examinations shall be flaw test and the base metal flaw test may be performed completed prior to grading the results and presenting the separately.
results to the candidate. Divulgence of particular specimen results or candidate viewing of unmasked specimens after the performance demonstration is prohibited.
2.1 Detection Test.
Flawed and unflawed grading units shall be randomly Flawed.... (base metal or overlay fabrication) ... each mixed. Although the boundaries of specific grading specimen.
units shall not be revealed to the candidate, the candidate shall be made aware of the type or types of grading units (base or overlay) that are present for each specimen.
2.2 Length Sizing Test fd) For flaws in base grading units, the candidate shall (d) For ... base Metal grading ... base metal wall estimate the length of that part of the flaw that is in the thickness.
outer 25% of the base wall thickness.
2.3 Depth Sizing Test.
For the depth sizing test, 80% of the flaws shall be sized (a) The depth sizing test may be conducted separately or at a specific location on the surface of the specimen in conjunction with the detection test.
identified to the candidate. For the remaining flaws, the (b) When the depth sizing test is conducted in regions of each specimen containing a flaw to be sized conjunction with the detection test and the detected flaws shall be identified to the candidate. The candidate shall do not satisfy the requirements of 1.1(f), additional determine the maximum depth of the flaw in each specimens shall be provided to the candidate. The region. regions containing a flaw to be sized shall be identified to the candidate. The candidate shall determine the maximum depth of the flaw in each region.
(c) For a separate depth sizing test, the regions of each specimen containing a flaw to be sized shall be identified to the candidate. The candidate shall determine the maximum depth of the flaw in each region.
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a ATTACHMENT (1)
RELIEF REQUEST TO USE ALTERNATIVE TECHNIQUES FOR REPAIR AND EXAMINATION OF UNACCEPTABLE INDICATIONS IN WELDED NOZZLES Table 4 Modifications to ASME Section XI Appendix VIII Supplement 11 SUPPLEMENT 11 -QUALIFICATION PDI PROGRAM:
REQUIREMENTS FOR FULL STRUCTURAL The Proposed Alternative to OVERLAID WROUGHT AUSTENITIC PIPING Supplement 11 Requirements WELDS 3.0 ACCEPTANCE CRITERIA 3.1 Detection Acceptance Criteria Examination procedures, equipment, and personnel are Examination procedures are qualified for detection when:
qualified for detection when the results of the a. All flaws within the scope of the procedure are performance demonstration satisfy the acceptance detected and the results of the performance criteria of Table V111-S2-4 for both detection and false demonstration satisfy the acceptance criteria of calls. The criteria shall be satisfied separately by the Table VIII-S2-1 for false calls.
demonstration results for base grading units and for b. At least one successful personnel demonstration has overlay grading unts. been performed meeting the acceptance criteria defined in (c).
- c. Examination equipment and personnel are qualified for detection when the results of the performance demonstration satisfy the acceptance criteria of Table VIII-S2-1 for both detection and false calls.
- d. The criteria in (b) and (c) shall be satisfied separately by the demonstration results for base metal grading units and for overlay fabrication grading units.
3.2 Sizing Acceptance Criteria (a) The RMS [root mean squared] error of the flaw (a) The ... base metal flaws is ... position.
length measurements, as compared to the true flaw lengths, is less than or equal to 0.75 inch. The length of base metal cracking is measured at the 75% through-base-metal position.
(b) All extensions of base metal cracking into the This requirement is omitted.
overlay material by at least 0.1 in. are reported as being The requirementfor reportingall extensions of cracking intrusions into the overlay material. into the overlay is omitted from the PDI Program because it is redundant to the RMS calculations performed in paragraph 3.2(c) and its presence adds confusion and ambiguity to depth sizing as required by paragraph 3.2(c). This also makes the wveld overlay program consistent with the Supplement 2 depth sizing criteria.
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