ML050690056
| ML050690056 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 03/05/2005 |
| From: | Vanderheyden G Constellation Energy Group |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML050690056 (15) | |
Text
George Vanderheyden Vice President Calvert Cliffs Nuclear Power Plant Constellation Generation Group, LLC 1650 Calvert Cliffs Parkway Lusby, Maryland 20657 410.495.4455 410.495.3500 Fax I
Constellation Energy March 5, 2005 U. S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION:
SUBJECT:
Document Control Desk Calvert Cliffs Nuclear Power Plant Unit Nos. I & 2; Docket Nos. 50-317 & 50-318 ASME Section XI Relief Request to Use Weld Overlay and Associated Alternative Techniques
REFERENCES:
(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)
(b)
Letter from K. Nietmann (CCNPP) to Document Control Desk (NRC),
dated February 18, 2005, ASME Section XI Relief Request to Use Weld Overlay and Associated Alternative Techniques 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), that provide an acceptable level of quality and safety, when authorized by the Director of the Office of Nuclear Reactor Regulation.
We withdraw the previously submitted relief request (Reference b) and supercede it with this request.
Note that we have withdrawn many portions of the original relief request from consideration based on actual inspection and repair information. Additional justification has been provided for some portions of the relief request.
Ac%+7
Document Control Desk March 5, 2005 Page 2 The Third Ten-Year Inservice Inspection Program Plan for Calvert Cliffs Units 1 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 REOUEST Article IWA-4000 of ASME Code,Section XI, and NRC approved Code Case N-504-2 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. Similar relief requests have been previously approved for other licensees including AmerGen Energy Company for its Three Mile Island Nuclear Station, Unit I on July 21, 2004. The detailed relief request and justification is provided in Attachment (1).
In addition, please note that Code Case N-638 will be used for similar and dissimilar metal welding using the ambient temperature machine Gas Tungsten Arc Welding temper bead technique without the specified preheat or post-weld heat treatment of the Construction Code, as it is impractical for operational and radiological reasons to drain the components. No relief is requested for the use of Code Case N-638.
SCHEDULE The structural weld overlay will be applied to welds 2-DR-2007-1 and 2-LD-2004-1, which were UT examined and determined to have unacceptable flaws during the Calvert Cliffs Unit 2 Spring 2005 refueling outage. We request that the Nuclear Regulatory Commission review and approve our proposed alternative by March 10, 2005 to support our start up from this outage.
Should you have questions regarding this matter, we will be pleased to discuss them with you.
Very tru
- ours, KJN/GT/bjd
Attachment:
(1)
Relief Request To Use Alternative Techniques for Repair and Examination of Unacceptable Indications in Welded Nozzles cc:
C. W. Fleming, Esquire Resident Inspector, NRC R. V. Guzman, NRC R. l. McLean, DNR S. J. Collins, NRC
ATTACHMENT (1)
RELIEF REQUEST TO USE ALTERNATIVE TECHNIQUES FOR REPAIR AND EXAMINATION OF UNACCEPTABLE INDICATIONS IN WELDED NOZZLES Calvert Cliffs Nuclear Power Plant, Inc.
March 5,2005
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, 2-DR-2007-1 and 2-LD-2004-1, which were examined under the PDI program and determined to have unacceptable indications attributed to primary water stress corrosion cracking (PWSCC) in existing Alloy 82/182 welds.
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 Case N-504-2. Tables 1-3 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 (P1). The pipe is austenitic stainless steel (P8). The existing weld filler material is Alloy 82/182 (F43 equivalent to P43). The overlay was 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 satisfies all the structural design requirements of the pipe as if the pipe were not there. As shown in Figure 1 below, the structural weld overlay (weld reinforcement) completely covers the existing Alloy 82/182 weld metal and extends onto the ferritic and austenitic stainless steel material on each end. Although the weld overlay extends the full 360° around the nozzle, only half is shown in Figure I for clarity.
Figure 1 teunic 1107.71C Structural I
1Exsting Alloy 82/182 wfld metal overlay L.Existing Alloy 82/12 weld.
Austcnitic stainless stel Tables 1, 2, and 3 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 IWA-4000 of the 1998 Edition, no Addenda, of ASME Section XI as modified and supplemented in Table 1. Certain requirements of IWA4000, 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]. Ultrasonic examination of the completed structural overlay will be accomplished in accordance with ASME Section XI, Appendix VIII Supplement 11, modified to comply with the Performance Demonstration Initiative (PDI) program as shown in Table 3. Any applicable requirements not modified by Tables 1, 2 or 3 will be met as described in IWA-4000, Appendix VIII Supplement 11, and Code Cases N-504-2 and N-638.
I
ATTACHMENT (1)
RELIEF REQUEST TO USE ALTERNATIVE TECHNIQUES FOR REPAIR AND EXAMINATION OF UNACCEPTABLE INDICATIONS IN WELDED NOZZLES 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.
CONCLUSION:
Calvert Cliffs believes the proposed alternatives to Article IWA-4000, Appendix V1II, Supplement 11, and NRC approved Code Case N-504-2, as described in this request, provide an acceptable level of quality and safety.
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ATTACHMENT (1)
RELIEF REQUEST TO USE ALTERNATIVE TECHNIQUES FOR REPAIR AND EXAMINATION OF UNACCEPTABLE INDICATIONS IN WELDED NOZZLES Table I Relief Requests Related to IWA-4000 IWA-4000 Differences/Basis for Relief-IWA-4421(a) Welding, brazing, metal removal, and Relief.
In lieu of meeting the requirements of IWA-installation activities shall be performed in accordance 4421(a) and IWA-46 11.1(a) which require the removal with the Owner's Requirements and Construction code of defects, the methodology of Code Case 504-2 will be of the component or system...
used to overlay the welds with defects (as modified on IWA-4611.1 (a) Defects shall be removed or reduced in Table 2). Removal of defects would present a hardship size in accordance with this paragraph.
in that a core off-load, system drain and extension to the refueling outage would be required. A core off-load is not scheduled for this outage.
IWA461 0(a) The area to be welded plus a band around Relief.
In lieu of weld-attached thermocouples and the area of at least 1-1/2 times the component thickness recording instruments, we plan to monitor the process or 5 in. (127 mm), whichever is less, shall be preheated temperatures with non-attached devices, e.g., contact and maintained at a minimum temperature of 3500F pyrometers and provide a manual record of the process (1771C) for the SMAW process and 3001F (1491C) for temperatures.
the GTAW process during welding.
The maximum The contact pyrometers used will be calibrated in interpass temperature shall be 450'F (2321C).
accordance with our control and calibration of Thermocouples and recording instruments shall be used measuring and test equipment program.
to monitor the process temperatures. Their attachment and removal shall be in accordance with Section III.
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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 iCode Case N-504-2 Differenceslasis 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 (P1) and nickel alloy (F43/P43) base material as well and Addenda up to and including the 1989 Edition as the austenitic stainless steel (P8) 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 (PI) with existing nickel alloy weld 1995 Edition with the 1995 Addenda and later metal (F43/P43) to which an austenitic stainless steel (P8)
Editions and Addenda, defect in austenitic stainless pipe is welded. Industry operational experience has shown steel piping may be reduced to a flaw of acceptable that PWSCC in Alloy 82/182 will blunt at the interface with size in accordance with IWB-3640 from the 1983 stainless steel base metal, ferritic base metal, or Alloy Edition with the Winter 1985 Addenda, or later 52/52M/152 weld metal. Calvert Cliffs plans to apply a Editions and Addenda, by deposition of weld 3600, full structural weld overlay to control growth in any reinforcement (weld overlay) on the outside surface PWSCC crack and maintain weld integrity. The weld of the pipe, provided the following requirements are overlay will put compressive stress around the weldment, met:
thus impeding growth of any existing crack and therefore, will fulfill all structural requirements, independent of the existing weld.
(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.
360° around the circumference of the pipe, and shall The weld metal will be either ERNiCrFe-7 (Alloy 52, be deposited in accordance with a qualified welding UNS N06052) or ERNiCrFe-7A (Alloy 52M, UNS N06054).
procedure specification identified in the Repair ENiCrFe-7 may be used to SMAW seal weld the initial base Program.
metal surfaces or to perform repair on the weld reinforcement.
These weld metals are assigned F43 by ASME per Code Case 2142-2. Alloy 52MS may also be used. Alloy 52MS is a trade designation for Alloy 52M with additional cleaning requirements during manufacture and meets all requirements of Alloy 52M. The requirements of ASME Section III, NB-2400 will be applied to all filler material.
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.)
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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 (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 Alloy delta ferrite content of at least 7.5 FN. The first 52/52M/152 are 100% austenitic and contain no delta ferrite layer of weld metal with delta ferrite content of least due to the high nickel composition (approximately 60%
7.5 FN shall constitute the first layer of the weld nickel).
reinforcement design thickness. Alternatively, first layers of at least 5 FN may be acceptable based on evaluation.
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ATTACHMENT (1)
RELIEF REQUEST TO USE ALTERNATIVE TECHNIQUES FOR REPAIR AND EXAMINATION OF UNACCEPTABLE INDICATIONS IN WELDED NOZZLES 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.
The italicized portions of the table provide an explanation of the proposed alternative.
Relief is requested to allow closer spacing of flaws provided they don't interfere with detection or discrimination.
The specimens used to date for qualification to the Tri-party (NRC/BWROG/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 Tfi-party test specimens into their weld overlay program.
Table 3 Modifications to 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 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 contained in the last sentence was reworded and the applicable to pipe diameters of 24 in. or larger, the phrase "and the remainder shall be alternative flaivs" specimen set must include at least one specimen 24 in. l'as added to the next to last sentence in paragraph or larger but need not include the maximum diameter.
1 I (d)i)
The specimen set must include at least one specimen with overlay thickness within -0.1 in. to +0.25 in. of the maximum nominal overlay thickness for which the procedure is applicable.
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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 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 (d) Flaw Conditions (1) Base metal flavs. All flaws must be cracks in or near the butt weld heat-affected zone, open to the inside surface, and extending at least 75% through the base metal wall. Flaws may extend 100% through the base metal and into the overlay material; in this case, intentional overlay fabrication flaws shall not interfere with ultrasonic detection or characterization of the cracking.
Specimens containing intergranular stress corrosion cracking shall be used when available.
(1)...must be in or...
intentional overlay fabrication flaws shall not interfere with ultrasonic detection or characterization of the base metal flaws.
Specimens containing intergranular stress corrosion cracking shall be used when available. At least 70% of the flaws in the detection and sizing tests shall be cracks and the remainder shall be alternative flaws.
Alternative flaw mechanisms, if used, shall provide crack-like reflective 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 ferrific 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 paragraph to allow use of alternative flawv mechanisms under controlled conditions. For example, alternativeflaws shall be limited to when implantation of cracks precludes obtaining an effective ultrasonic response, flaws shall be semi elliptical with 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 remainder shall be alternativeflaws.
To avoid confusion, the overlay thickness tolerance contained in paragraph 1.1(b) last sentence, wias reworded and the phrase "and the remainder shall be alternativeflawvs" was added to the next to last sentence.
Paragraph 1.1(d)(1) includes the statement that intentional overlay fabrication flaws shall not interfere with ultrasonic detection or characterization of the base metalflaws.
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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 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 (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 +20° 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 requirement for axially oriented overlay fabrication should be treated as single or multiple flaws.
flavs was excluded from the PDI Program as an improbable scenario Meld overlays are typically applied using automated GTA IV techniques with the filler metal applied in a circumferential direction. Because resultant fabrication induced discontinuities would also be expected to have major dimensions oriented in the circumferential direction axial overlay fabrication flauss are unrealistic.
The requirement for using IWA-3300 for proximity flaw evaluation wsas 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.
(a)(l) A base grading unit shall include at least 3 in. of (a)(J)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 description of a base metal grading unit. The PDI 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" ivere changed to the term 'flaws" because of the use ofalternativeflawv mechanisms.
Modified to require that a base metal grading unit include at least I in. of the length of the overlaid weld, rather than 3 inches.
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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 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)(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 I 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 Modified 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.
rather than the I inch requirement.
(b)(l) An overlay grading unit shall include the overlay (b)(1) 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 rectangular, interface for a length of at least I in.
with minimum dimensions of 2 in.
Modified to define an overlay fabrication grading unit as including the overlay material and the base metal-to-overlay interface for a length of at least I in, rather than the 6 in2 requirement (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 unflaived 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 I 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.
Paragraph 1.1(e)(2)(b)(2) states that overlayfabrication grading units designed to be unflawed shall be separated by unflared overlay material and unflawed base metal-to-overlay interface for at least I in. at both ends, rather than around its entire perimeter.
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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 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)(3)
Detection sets shall be selected from
...base metal grading units, ten unflawed base metal Table VIII-S2-4. 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 flaived 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.
CO Sizing Specimen (I) The minimum number of flaws shall be ten. At least (1) 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.
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.
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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 Appendix VIII, Supplement II SUPPLEMENT I 1 - QUALIFICATION PDI PROGRAM:
REQUIREMENTS FOR FULL STRUCTURAL The Proposed Alternative to OVERLAID WROUGHT AUSTENITIC PIPING Supplement 11 Requirements WELDS 2.2 Length Sizing Test (d) 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.
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 VIII-S2-1 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 units.
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.
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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 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 3.2 Sizing Acceptance Criteria (a) The RMS error of the flaw length measurements, as (a) The... base metal flaws is... position.
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 requirement for reporting all 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 weld overlay program consistent with the Supplement 2 depth sizing criteria.
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