GO2-03-185, Implementation of the Performance Demonstration Methods Supplement Ten (10) Qualification Requirements for Dissimilar Metal Welds.
| ML033640600 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 12/15/2003 |
| From: | Atkinson D Energy Northwest |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| GO2-03-185 | |
| Download: ML033640600 (25) | |
Text
ENWERGY NORTHWEST PO. Box 968
- Richland, Washington 99352-0968 December 15, 2003 G02-03-185 United States Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001 10CFR50.55a
Subject:
COLUMBIA GENERATING STATION, DOCKET NO. 50-397 IMPLEMENTATION OF THE PERFORMANCE DEMONSTRATION METHODS SUPPLEMENT TEN (10) "QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL WELDS"
References:
- 1) Letter dated March 25, 2003, MP Gallagher (Exelon Generating/AmerGen Energy Company) to U.S. Nuclear Regulatory Commission, Implementation of the Performance Demonstration Methods Supplement Ten (10) - "Qualification Requirements for Dissimilar Metal Piping Welds"
- 2) Letter dated July 16, 2003, JW Clifford (NRC) to JL Skolds (Exelon Nuclear), "Relief for Qualification Requirements for Dissimilar Metal Piping Welds"
Dear Sir or Madam:
Pursuant to 10 CFR 50.55a(a)(3)(i), Energy Northwest requests approval of a proposed alternative concerning performance demonstration methods for ultrasonic examination systems for the Columbia Generating Station. Specifically, this proposed alternative concerns dissimilar metal piping welds as implemented by Supplement 10 of ASME Section XI, Appendix VIII. The proposed alternative is described in Attachment 1. Attachment 2 is a copy of proposed revisions to Supplement 10 as provided by the Electric Power Research Institute - Performance Demonstration Initiative (PDI), and is provided to assist the NRC in their review of this request. These proposed revisions provided by the PDI identify additional clarifications and enhancements.
A similar request (Reference 1) was submitted to the NRC for the Exelon Generating/AmerGen Energy Company. Reference 2 is the NRC's approval of Exelon's request. Other precedents are identified in Attachment 1.
IMPLEMENTATION OF THE PERFORMANCE DEMONSTRATION METHODS SUPPLEMENT TEN (10)
Page 2 We request your review and approval of this request by August 15, 2004 to support planning for Columbia Generating Station's Spring 2005 refuel outage.
If you have any questions or desire additional information pertaining to this letter, please call Ms. CL Perino at (509) 377-2075.
Respectfully, IQ, ,i4a -
DK Atkinson Vice President, Technical Services Mail Drop PE08 Attachments cc: BS Mallet - NRC RIV BJ Benney - NRC NRR NRC Senior Resident Inspector/988C RN Sherman - BPA/1399 TC Poindexter - Winston & Strawn
ALTERNATIVE PERFORMANCE DEMONSTRATION METHODS Page 1 of 7 RELIEF REQUEST 21SI-26 ASME Code Components Affected Dissimilar metal piping welds subject to examination using procedures, personnel, and equipment qualified to ASME Section XI, Appendix VIII, Supplement 10 criteria.
Applicable Code Edition and Addenda
Second Inspection Interval 2/10/1995 to 12/12/2005 ASME Section XI 1989 Edition, no Addenda ASME Section XI Appendix VIII 1995 Edition, 1996 Addenda Applicable Code Requirements The following paragraphs or statements are from ASME Section XI, Appendix VIII, Supplement 10, and identify the specific requirements that are included in this request for relief:
Item 1 - Paragraph 1.1(b) states in part - Pipe diameters within a range of 0.9 to 1.5 times a nominal diameter shall be considered equivalent.
Item 2 - Paragraph 1.1(d) states - All flaws in the specimen set shall be cracks.
Item 3 - Paragraph 1.l(d)(1) states - At least 50% of the cracks shall be in austenitic material.
At least 50% of the cracks in austenitic material shall be contained wholly in weld or buttering material. At least 10% of the cracks shall be in ferritic material. The remainder of the cracks may be in either austenitic or ferritic material.
Item 4 - Paragraph 1.2(b) states - Detection sets shall be selected from Table VIII-S2-1. The number of unflawed grading units shall be at least twice the number of flawed grading units.
Item 5 - Paragraph 1.2(c)(1) and 1.3(c) state in part - At least 1/3 of the flaws, rounded to the next higher whole number, shall have depths between 10% and 30% of the nominal pipe wall thickness. Paragraph 1.4(b) distribution table requires 20% of the flaws to have depths between 10% and 30%.
Item 6 - Paragraph 2.0 first sentence states - The specimen inside surface and identification shall be concealed from the candidate.
Item 7 - Paragraph 2.2(b) states in part - The regions containing a flaw to be sized shall be identified to the candidate.
ALTERNATIVE PERFORMANCE DEMONSTRATION METHODS Page 2 of 7 Item 8 - Paragraph 2.2(c) states in part - For a separate length sizing test, the regions of each specimen containing a flaw to be sized shall be identified to the candidate.
Item 9 - Paragraph 2.3(a) states - For the depth sizing test, 80% of the flaws shall be sized at a specific location on the surface of the specimen identified to the candidate.
Item 10 - Paragraph 2.3(b) states - For the remaining flaws, 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.
Item 11 - Table VIII-S2-1 provides the false call criteria when the number of unflawed grading units is at least twice the number of flawed grading units.
Proposed Alternative and Basis for Use Pursuant to 10 CFR 50.55a(a)(3)(i), in lieu of the requirements of ASME Section XI, 1995 Edition, 1996 Addenda, Appendix VIII, Supplement 10, the proposed alternate discussed below shall be used. It will be implemented through the Performance Demonstration Initiative (PDI) Program. Compliance with the proposed alternatives will provide an adequate level of quality and safety for examination of the affected welds.
As provided by the PDI, a copy of the proposed revision to Supplement 10 is provided as . Attachment 2 identifies proposed revisions and allows them to be viewed in context. It also identifies additional clarifications and enhancements for information. The proposed revisions have been incorporated into ASME Code Case N-695. ASME Code Case N-695 was approved by ASME on May 21, 2003.
Item 1 - The proposed alternative to Paragraph 1.1(b) states:
"The specimen set shall include the minimum and maximum pipe diameters and thicknesses for which the examination procedure is applicable. Pipe diameters within a range of 1/2 in. (13 mm) of the nominal diameter shall be considered equivalent. Pipe diameters larger than 24 in.
(610 mm) shall be considered to be flat. When a range of thicknesses is to be examined, a thickness tolerance of +25% is acceptable."
Technical Basis - The change in the minimum pipe diameter tolerance from 0.9 times the diameter to the nominal diameter minus 0.5 inch provides tolerances more in line with industry practice. Though the alternative is less stringent for small pipe diameters they typically have a thinner wall thickness than larger diameter piping. A thinner wall thickness results in shorter sound path distances that reduce the detrimental effects of the curvature. This change maintains consistency between Supplement 10 and the recent revision to ASME Section XI, Appendix VIII, Supplement 2.
ALTERNATIVE PERFORMANCE DEMONSTRATION METHODS Page 3 of 7 Item 2 - The proposed alternative to Paragraph 1.1(d) states:
"At least 60% of the flaws shall be cracks, the remainder shall be alternative flaws.
Specimens with IGSCC shall be used when available. Alternative flaws, if used, shall provide crack-like reflective characteristics and shall be limited to the case where implantation of cracks produces spurious reflectors that are uncharacteristic of actual flaws. Alternative flaw mechanisms shall have a tip width of less than or equal to 0.002 inches (0.05 mm)."
Technical Basis - As illustrated below, implanting a crack requires excavation of the base material on at least one side of the flaw. 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. In addition, it is important to preserve the dendritic structure present in field welds that would otherwise be destroyed by the implantation process. To resolve these issues, the proposed alternative allows the use of up to 40%
fabricated flaws as an alternative flaw mechanism under controlled conditions. The fabricated flaws are isostatically compressed which produces ultrasonic reflective characteristics similar to tight cracks. To avoid confusion, the proposed alternative modifies instances of the term "cracks" or "cracking" to the term "flaws" because of the use of "alternative flaw mechanisms."
] xat1 1 Mechanical fatigue crack
(~~~~p
~~~in Base rnaterial Item 3 - The proposed alternative to Paragraph 1.I(d)(1) states:
'At least 80% of the flaws shall be contained wholly in weld or buttering material. At least one and a maximum of 10% of the flaws shall be in ferritic base material. At least one and a maximum of 10% of the flaws shall be in austenitic base material."
Technical Basis - Under the current Code, as few as 25% of the flaws are contained in austenitic weld or buttering material. The metallurgical structure of austenitic weld material is ultrasonically more challenging than either ferritic or austenitic base material. The proposed alternative is therefore more challenging than the current Code.
Item 4 - The proposed alternative to Paragraph 1.2(b) states:
"Detection sets shall be selected from Table VIII-S1O-1. The number of unflawed grading units shall be at least one and a half times the number of flawed grading units."
ALTERNATIVE PERFORMANCE DEMONSTRATION METHODS Page 4 of 7 Technical Basis - New Table VIII-SlO-l provides a statistically based ratio between the number of unflawed grading units and the number of flawed grading units. The proposed alternative reduces the ratio to 1.5 times to reduce the number of test samples to a more reasonable number. However, the statistical basis used for screening personnel and procedures is still maintained at the same level with competent personnel being successful and less skilled personnel being unsuccessful. The acceptance criteria for the statistical basis are in Table VIll-Slo-1.
Item 5 - The proposed alternative to the flaw distribution requirements of Paragraph 1.2(c)(1)
(detection) and 1.3(c) (length) is to use the Paragraph 1.4(b) (depth) distribution table (see below) for all qualifications.
Flaw Depth Minimum
(% Wall Thickness) Number of Flaws 10-30% 20%
31-60% 20%
61-100% 20%
In addition, the proposed alternative includes the following: "At least 75% of the flaws shall be in the range of 10 to 60% of wall thickness."
Technical Basis - The proposed alternative uses the depth sizing distribution for both detection and depth sizing because it provides for a better distribution of flaw sizes within the test set.
This distribution allows candidates to perform detection, length, and depth sizing demonstrations simultaneously utilizing the same test set. The requirement that at least 75% of the flaws shall be in the range of 10 to 60% of wall thickness provides an overall distribution tolerance yet the distribution uncertainty decreases the possibilities for testmanship that would be inherent to a uniform distribution. It must be noted that it is possible to achieve the same distribution utilizing the present requirements, but it is preferable to make the criteria consistent.
Item 6 - The proposed alternative to Paragraph 2.0 first sentence states:
"For qualifications from the outside surface, the specimen inside surface and identification shall be concealed from the candidate. When qualifications are performed from the inside surface, the flaw location and specimen identification shall be obscured to maintain a "blind test."
Technical Basis - The current Code requires that the inside surface be concealed from the candidate. This makes qualifications conducted from the inside of the pipe (e.g., PWR nozzle to safe end welds) impractical. The proposed alternative differentiates between ID and OD scanning surfaces, requires that they be conducted separately, and requires that flaws be concealed from the candidate.
ALTERNATIVE PERFORMANCE DEMONSTRATION METHODS Page 5 of 7 Items 7 and 8 - The proposed alternatives to Paragraph 2.2(b) and 2.2(c) state:
.... containing a flaw to be sized may be identified to the candidate.'
Technical Basis - The current Code requires that the regions of each specimen containing a flaw to be length sized shall be identified to the candidate. The candidate shall determine the length of the flaw in each region (Note, that length and depth sizing use the term "regions" while detection uses the term "grading units" - the two terms define different concepts and are not intended to be equal or interchangeable). To ensure security of the samples, the proposed alternative modifies the first "shall" to a "may" to allow the test administrator the option of not identifying specifically where a flaw is located.
Items 9 and 10 - The proposed alternatives to Paragraph 2.3(a) and 2.3(b) state:
"... regions of each specimen containing a flaw to be sized may be identified to the candidate."
Technical Basis - The current Code requires that a large number of flaws be sized at a specific location. The proposed alternative changes the "shall" to a "may" which modifies this from a specific area to a more generalized region to ensure security of samples.
Item 11 - The proposed alternative modifies the acceptance criteria of Table VIII-S2-1 as follows:
ALTERNATIVE PERFORMANCE DEMONSTRATION METHODS Page 6 of 7 r1._ I1 TABLE VIIl-S-l 1 PERFORMAN( CE DEMONSTRATION DETECTION TEST ACCEPTANCE CRITERIA Detection Test False Call Test Acceptance Critera Acceptance Criteria No. of No. of Maximum Flawed Minimum Unflawed Number Grading Detection Grading of False Units Criteria Units Calls 5 5 10 0 6 6 12 7 - 6 14 1 8 7 16 2 7 7 10 2 10 8 2-15 a 2 11 9 22 17 3 3 12 9 2- 18 3 13 10 2-20 4-3 14 10 2e 21 3 15 11 30- 23 5 3 16 12 32 24 6- 4 17 12 34. 26 4 18 13 3 27 4 19 13 7 20 14 4030 5 Technical Basis - The proposed alternative is identified as new Table VIII-SIO-1 above. It is a modified version of Table VIII-S2-1 to reflect the reduced number of unflawed grading units and allowable false calls. As provided by the PDI, and as part of ongoing Code activities, Pacific Northwest National Laboratories (PNNL) has reviewed the statistical significance of these revisions and offered the revised Table S10-1.
Duration of Proposed Alternative The proposed alternative is for use for the remainder of the second ISI inspection interval, which ends December 12, 2005.
Precedents
- 1) Letter dated March 25, 2003, MP Gallagher (Exelon Generating/AmerGen Energy Company) to U.S. Nuclear Regulatory Commission, Implementation of the Performance
ALTERNATIVE PERFORMANCE DEMONSTRATION METHODS Page 7 of 7 Demonstration Methods Supplement Ten (10) - "Qualification Requirements for Dissimilar Metal Piping Welds"
- 2) Letter dated July 16, 2003, JW Clifford (NRC) to JL Skolds (Exelon Nuclear), 'Relief for Qualification Requirements for Dissimilar Metal Piping Welds"
- 3) Letter dated October 23, 2003, PE Katz (Constellation Energy Group) to U.S. Nuclear Regulatory Commission, "Request for Relief from Qualification Requirements for Dissimilar Metal Piping Welds"
- 4) Letter dated November 21, 2003, RJ Laufer (NRC) to PE Katz (Constellation Energy Group), "Authorization of Relief Regarding Dissimilar Metal Piping Welds" References ASME Section XI Code Case N-695, "Qualification Requirements for Dissimilar Metal Piping Welds,"
SUPPLEMENTAL INFORMATION PROVIDED BY THE PERFORMANCE DEMONSTRATION INITIATIVE (PDI)
Page 1of 16 SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning 1.0 SCOPE Supplement 10 is applicable to dissimilar A scope statement provides added clarity metal piping welds examined from either regarding the applicable range of each the inside or outside surface. individual Supplement. The exclusion of Supplement 10 is not applicable to CRC provides consistency between piping welds containing supplemental Supplement 10 and the recent revision to corrosion resistant clad (CRC) applied to ASME Section XI, Appendix VIII, mitigate Intergranular Stress Corrosion Supplement 2 (Reference BC 00-755).
Cracking (IGSCC). Note, an additional change identifying CRC as "in course of preparation" is being processed separately.
1.0 SPECIMEN REQUIRE S2.0 SPECIMEN REQUIREMENTS Renumbered.
Qualification test specimens shall meet the Qualification test specimens shall meet the No Change.
requirements listed herein, unless a set of requirements listed herein, unless a set of specimens is designed to accommodate specimens is designed to accommodate specific limitations stated in the scope of specific limitations stated in the scope of the examination procedure (e.g., pipe size, the examination procedure (e.g., pipe size, weld joint configuration, access weld joint configuration, access limitations). The same specimens may be limitations). The same specimens may be used to demonstrate both detection and used to demonstrate both detection and sizing qualification. sizing qualification.
1.1 General. The specimen set shall 2.1 General. The specimen set shall Renumbered.
conform to the following requirements. conform to the following requirements.
(a) The minimum number of flaws in a New. Changed minimum number of flaws test set shall be ten. to 10 so sample set size for detection is
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Page 2 of 16 SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement - Proposed Change Reasoning consistent with length and depth sizing.
(a) Specimens shall have sufficient volume (b) Specimens shall have sufficient volume Renumbered.
to minimize spurious reflections that may to minimize spurious reflections that may interfere with the interpretation process. interfere with the interpretation process.
(b) The specimen set shall include the (c) The specimen set shall include the Renumbered, metricated, the change in minimum and maximum pipe diameters minimum and maximum pipe diameters pipe diameter tolerance provides and thicknesses for which the examination and thicknesses for which the examination consistency between Supplement 10 and procedure is applicable. Pipe diameters procedure is applicable. Pipe diameters the recent revision to Supplement 2 within a range of 0.9 to 1.5 times a within a range of 1/2 in. (13 mm) of the (Reference BC 00-755).
nominal diameter shall be considered nominal diameter shall be considered equivalent. Pipe diameters larger than 24 equivalent. Pipe diameters larger than 24 in. shall be considered to be flat. When a in. (610 mm) shall be considered to be range of thicknesses is to be examined, a flat. When a range of thicknesses is to be thickness tolerance of +25% is acceptable. examined, a thickness tolerance of +25%
is acceptable.
(c) The specimen set shall include (d) The specimen set shall include Renumbered, changed "condition" to examples of the following fabrication examples of the following fabrication "conditions."
condition: conditions:
(1) geometric conditions that normally (1) geometric and material conditions that Clarification, some of the items listed require discrimination from flaws (e.g., normally require discrimination from flaws relate to material conditions rather than counterbore or weld root conditions, (e.g., counterbore or weld root conditions, geometric conditions. Weld repair areas cladding, weld buttering, remnants of cladding, weld buttering, remnants of were added as a result of recent field previous welds, adjacent welds in close previous welds, adjacent welds in close experiences.
proximity); proximity, and weld repair areas);
(2) typical limited scanning surface (2) typical limited scanning surface Differentiates between ID and OD
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Page 3 of 16 SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning conditions (e.g., diametrical shrink, single- conditions (e.g., weld crowns, diametrical scanning surface limitations. Requires that side access due to nozzle and safe end shrink, single-side access due to nozzle and ID and OD qualifications be conducted external tapers). safe end external tapers for outside independently (Note, new paragraph 2.0 surface examinations; and internal (identical to old paragraph 1.0) provides tapers, exposed weld roots, and cladding for alternatives when "a set of specimens conditions for inside surface is designed to accommodate specific examinations). Qualification limitations stated in the scope of the requirements shall be satisfied separately examination procedure.").
for outside surface and inside surface examinations.
(d) All flaws in the specimen set shall be Deleted this requirement, because new cracks. paragraph 2.3 below provides for the use of "alternative flaws" in lieu of cracks.
(1) At least 50% of the cracks shall be in 2.2 Flaw Location. At least 80% of the Renumbered and re-titled. Flaw location austenitic material. At least 50% of the flaws shall be contained wholly in weld or percentages redistributed because field cracks in austenitic material shall be buttering material. At least one and a experience indicates that flaws contained in contained wholly in weld or buttering maximum of 10% of the flaws shall be in weld or buttering material are probable and material. At least 10% of the cracks shall ferritic base material. At least one and a represent the more stringent ultrasonic be in ferritic material. The remainder of maximum of 10% of the flaws shall be in detection scenario.
the cracks may be in either austenitic or austenitic base material.
ferritic material.
(2) At least 50% of the cracks in austenitic 2.3 Flaw Type. Renumbered and re-titled. Alternative base material shall be either IGSCC or (a) At least 60% of the flaws shall be flaws are required for placing axial flaws thermal fatigue cracks. At least 50% of cracks, the remainder shall be in the HAZ of the weld and other areas the cracks in ferritic material shall be alternative flaws. Specimens with where implantation of a crack produces
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Page 4 of 16 SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning mechanically or thermally induced fatigue IGSCC shall be used when metallurgical conditions that result in an cracks. available. Alternative flaws, if unrealistic ultrasonic response. This is used, shall provide crack-like consistent with the recent revision to reflective characteristics and shall Supplement 2 (Reference BC 00-755).
be limited to the case where implantation of cracks produces The 40% limit on alternative flaws is spurious reflectors that are needed to support the requirement for up uncharacteristic of actual flaws. to 70% axial flaws. Metricated.
Alternative flaw mechanisms shall have a tip width of less than or equal to 0.002 in. (.05 mm).
(3) At least 50% of the cracks shall be (b) At least 50% of the flaws shall be Renumbered. Due to inclusion of coincident with areas described in (c) coincident with areas described in 2.1(d) "alternative flaws", use of "cracks" is no above. above. longer appropriate.
2.4 Flaw Depth. All flaw depths shall be Moved from old paragraph 1.3(c) and 1.4 greater than 10% of the nominal pipe wall and re-titled. Consistency between thickness. Flaw depths shall exceed the detection and sizing specimen set nominal clad thickness when placed in requirements (e.g., 20% vs. 1/3 flaw depth cladding. Flaws in the sample set shall increments, e.g., original paragraph be distributed as follows: 1.3(c)).
Flaw Depth Minimum
(% Wall Thickness) Number of Flaws 10-30% 20%_
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Page 5 of 16 SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning 31-60% 20%
61-100% 20%
At least 75% of the flaws shall be in the range of 10 to 60% of wall thickness.
1.2 Detection Specimens. The specimen Renumbered and re-titled and moved to set shall include detection specimens that paragraph 3. 1(a). No other changes.
meet the following requirements.
(a) Specimens shall be divided into grading Renumbered to paragraph 3.1(a)(1). No units. Each grading unit shall include at other changes.
least 3 in. of weld length. If a grading unit is designed to be unflawed, at least 1 in. of unflawed material shall exist on either side of the grading unit. The segment of weld length used in one grading unit shall not be used in another grading unit. Grading units need not be uniformly spaced around the pipe specimen.
(b) Detection sets shall be selected from Moved to new paragraph 3.1 (a)(2).
Table VHI-S2-1. The number of unflawed grading units shall be at least twice the number of flawed grading units.
(c) Flawed grading units shall meet the Flaw depth requirements moved to new following criteria for flaw depth, paragraph 2.4, flaw orientation orientation, and type. requirements moved to new paragraph 2.5,
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Page 6 of 16 SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning flaw type requirements moved to new paragraph 2.3, "Flaw Type."
(1) All flaw depths shall be greater than Deleted, for consistency in sample sets the 10% of the nominal pipe wall thickness. depth distribution is the same for detection At least 1/3 of the flaws, rounded to the and sizing.
next higher whole number, shall have depths between 10% and 30% of the nominal pipe wall thickness. However, flaw depths shall exceed the nominal clad thickness when placed in cladding. At least 1/3 of the flaws, rounded to the next whole number, shall have depths greater than 30% of the nominal pipe wall thickness.
(2) At least 30% and no more than 70% of 2.5 Flaw Orientation. Note, this distribution is applicable for the flaws, rounded to the next higher (a) At least 30% and no more than 70% of detection and depth sizing. Paragraph whole number, shall be oriented axially. the flaws, rounded to the next higher 2.5(b)(1) requires that all length- sizing The remainder of the flaws shall be whole number, shall be oriented axially. flaws be oriented circumferentially.
oriented circumferentially. The remainder of the flaws shall be oriented circumferentially.
1.3 Length Sizing Specimens. The Renumbered and re-titled and moved to specimen set shall include length sizing new paragraph 3.2.
specimens that meet the following requirements.
(a) All length sizing flaws shall be oriented Moved, included in new paragraph 3.2(a)
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Page 7of16 SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement l Proposed Change Reasoning circumferentially.
(b) The minimum number of flaws shall be Moved, included in new paragraph 2.1 ten. above.
(c) All flaw depths shall be greater than Moved, included in new paragraph 2.4 10% of the nominal pipe wall thickness. above after revision for consistency with At least 1/3 of the flaws, rounded to the detection distribution.
next higher whole number, shall have depths between 10% and 30% of the nominal pipe wall thickness. However, flaw depth shall exceed the nominal clad thickness when placed in cladding. At least 1/3 of the flaws, rounded to the next whole number, shall have depths greater than 30% of the nominal pipe wall thickness.
1.4 Depth Sizing Specimens. The Moved, included in new paragraphs 2.1, specimen set shall include depth sizing 2.3, 2.4.
specimens that meet the following requirements.
(a) The minimum number of flaws shall be Moved, included in new paragraph 2.1.
ten.
(b) Flaws in the sample set shall not be Moved, potential conflict with old wholly contained within cladding and shall paragraph 1.2(c)(1); "However, flaw be distributed as follows: depths shall exceed the nominal clad thickness when placed in cladding."
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Page 8 of 16 SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning Revised for clarity and included in new paragraph 2.4.
Moved, included in paragraph 2.4 for Flaw Depth Minimum consistent applicability to detection and
(% Wall Thickness) Number of Flaws sizing samples.
10-30% 20%
31-60% 20%
61-100% 20%
The remaining flaws shall be in any of the above categories.
(b) Sizing Specimen sets shall meet the Added for clarity.
following requirements.
(1) All length-sizing flaws shall be oriented Moved from old paragraph 1.3(a).
circumferentially.
(2) Depth sizing flaws shall be oriented Included for clarity. Previously addressed as in 2.5(a). by omission (i.e., length, but not depth had a specific exclusionary statement).
2.0 CONDUCT OF PERFORMANCE 3.0 CONDUCT OF PERFORMANCE Renumbered.
DEMONSTRATION DEMONSTRATION The specimen inside surface and For qualifications from the outside Differentiate between qualifications identification shall be concealed from the surface, the specimen inside surface and conducted from the outside and inside candidate. All examinations shall be identification shall be concealed from the surface.
completed prior to grading the results and candidate. When qualifications are presenting the results to the candidate. performed from the inside surface, the
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Page 9 of 16 SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Regnirement Proposed Change Reasoning Divulgence of particular specimen results flaw location and specimen identification or candidate viewing of unmasked shall be obscured to maintain a "blind specimens after the performance test". All examinations shall be completed demonstration is prohibited. prior to grading the results and presenting the results to the candidate. Divulgence of particular specimen results or candidate viewing of urnmasked specimens after the performance demonstration is prohibited.
2.1 Detection Test. Flawed and unflawed 3.1 Detection Qualification. Renumbered, moved text to paragraph grading units shall be randomly mixed. 3. l(a)(3)-
(a) The specimen set shall include Renumbered, moved from old paragraph detection specimens that meet the 1.2.
following requirements.
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Page 10 of 16 SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning (1) Specimens shall be divided into grading Renumbered, moved from old paragraph units. Each grading unit shall include at 1.2(a). Metricated. No other changes.
least 3 in. (76 mm) of weld length. If a grading unit is designed to be unflawed, at least 1 in. (25 mm) of unflawed material shall exist on either side of the grading unit. The segment of weld length used in one grading unit shall not be used in another grading unit. Grading units need not be uniformly spaced around the pipe specimen.
(2) Detection sets shall be selected from Moved from old paragraph 1.2(b). Table Table VIII-S10-1. The number of revised to reflect a change in the minimum unflawed grading units shall be at least one sample set to 10 and the application of and a halt times the number of flawed equivalent statistical false call parameters grading units. to the reduction in unflawed grading units.
Human factors due to large sample size.
(3) Flawed and unflawed grading units Moved from old paragraph 2.1.
shall be randomly mixed.
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Page 11 of 16 SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning (b) Examination equipment and personnel Moved from old paragraph 3.1. Modified are qualified for detection when personnel to reflect the 100% detection acceptance demonstrations satisfy the acceptance criteria of procedures versus personnel and criteria of Table VIII S10-1 for both equipment contained in new paragraph 4.0 detection and false calls. and the use of 1.5X rather than 2X unflawed grading units contained in new paragraph 3. 1(a)(2). Note, the modified table maintains the screening criteria of the
_________________________________ original T able V IH -S2-1.
2.2 Length Sizing Test 3.2 Length Sizing Test Renumbered.
(a) The length sizing test may be conducted (a) Each reported circumferential flaw in Provides consistency between Supplement separately or in conjunction with the the detection test shall be length sized. 10 and the recent revision to Supplement 2 detection test. (Reference BC 00-755).
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Page 12 of 16 SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning (b) When the length sizing test is (b) When the length sizing test is Change made to ensure security of conducted in conjunction with the detection conducted in conjunction with the detection samples, consistent with the recent revision test, and less than ten circumferential flaws test, and less than ten circumferential flaws to Supplement 2 (Reference BC 00-755).
are detected, additional specimens shall be are detected, additional specimens shall be Note, length and depth sizing use the term provided to the candidate such that at least provided to the candidate such that at least "regions" while detection uses the term ten flaws are sized. The regions ten flaws are sized. The regions "grading units." The two terms define containing a flaw to be sized shall be containing a flaw to be sized may be different concepts and are not intended to identified to the candidate. The candidate identified to the candidate. The candidate be equal or interchangeable.
shall determine the length of the flaw in shall determine the length of the flaw in each region. each region.
(c) For a separate length sizing test, the (c) For a separate length sizing test, the Change made to ensure security of regions of each specimen containing a flaw regions of each specimen containing a flaw samples, consistent with the recent revision to be sized shall be identified to the to be sized may be identified to the to Supplement 2 (Reference BC 00-755).
candidate. The candidate shall determine candidate. The candidate shall determine the length of the flaw in each region. the length of the flaw in each region.
(d) Examination procedures, equipment, Moved from old paragraph 3.2(a) includes and personnel are qualified for length inclusion of "when" as an editorial change.
sizing when the RMS error of the flaw Metricated.
length measurements, as compared to the true flaw lengths, is less than or equal to 0.75 in. (19 mm).
2.3 Depth Sizing Test 3.3 Depth Sizing Test Renumbered.
(a) For the depth sizing test, 80% of the (a) The depth sizing test may be Change made to ensure security of flaws shall be sized at a specific location conducted separately or in conjunction samples, consistent with the recent revision on the surface of the specimen identified to with the detection test. For a separate to Supplement 2 (Reference BC 00-755).
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Page 13 of 16 SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Chang e Reasoning the candidate. depth sizing test, the regions of each specimen containing a flaw to be sized may be identified to the candidate. The candidate shall determine the maximum depth of the flaw in each region.
(b) For the remaining flaws, the regions of (b) When the depth sizing test is Change made to be consistent with the each specimen containing a flaw to be conducted in conjunction with the recent revision to Supplement 2 (Reference sized shall be identified to the candidate. detection test, and less than ten flaws are BC 00-755).
The candidate shall determine the detected, additional specimens shall be maximum depth of the flaw in each region. provided to the candidate such that at Changes made to ensure security of least ten flaws are sized. The regions of samples, consistent with the recent revision each specimen containing a flaw to be to Supplement 2 (Reference BC 00-755).
sized may be identified to the candidate.
The candidate shall determine the maximum depth of the flaw in each region.
(c) Examination procedures, equipment, Moved from old paragraph 3.2(b).
and personnel are qualified for depth sizing Metricated.
when the RMS error of the flaw depth measurements, as compared to the true flaw depths, is less than or equal to 0.125 in. (3 mm).
3.0 ACCEPTANCE CRITERIA Delete as a separate category. Moved to new paragraph detection (3.1) and sizing 3.2 and 3.3.
3.1 Detection Acceptance Criteria. Moved to new paragraph 3.1(b), reference
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Page 14 of 16 SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning Examination procedures, equipment, and changed to Table S10 from S2 because of personnel are qualified for detection when the change in the minimum number of the results of the performance flaws and the reduction in unflawed demonstration satisfy the acceptance grading units from 2X to 1.5X.
criteria of Table VII-S2-1 for both detection and false calls.
3.2 Sizing Acceptance Criteria Deleted as a separate category. Moved to new paragraph on length 3.2 and depth 3.3.
(a) Examination procedures, equipment, Moved to new paragraph 3.2(d), included and personnel are qualified for length word "when" as an editorial change.
sizing the RMS error of the flaw length measurements, as compared to the true flaw lengths, is less than or equal to 0.75 inch.
(b) Examination procedures, equipment, Moved to new paragraph 3.3(c).
and personnel are qualified for depth sizing when the RMS error of the flaw depth measurements, as compared to the true flaw depths, is less than or equal to 0.125 in.
4.0 PROCEDURE QUALIFICATION New.
Procedure qualifications shall include New. Based on experience gained in the following additional requirements. conducting qualifications, the equivalent of (a) The specimen set shall include the 3 personnel sets (i.e., a minimum of 30
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Page 15 of 16 SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning equivalent of at least three personnel sets. flaws) is required to provide enough flaws Successful personnel demonstrations may to adequately test the capabilities of the be combined to satisfy these procedure. Combining successful requirements. demonstrations allows a variety of (b) Detectability of all flaws within the examiners to be used to qualify the scope of the procedure shall be procedure. Detectability of each flaw demonstrated. Length and depth sizing within the scope of the procedure is shall meet the requirements of required to ensure an acceptable personnel paragraph 3.2 and 3.3. pass rate. The last sentence is equivalent to (c) At least one successful personnel the previous requirements and is demonstration has been performed. satisfactory for expanding the essential (d) To qualify new values of essential variables of a previously qualified variables, at least one personnel procedure.
qualification set is required.
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Page 16 of 16 SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR I METAL PIPING WELDS Reasonin Current Requirement Proposed Change I ReasoningI TABLE VIlI-S -1E PERFORMANCE DEMONSTRATION DETECTION TEST ACCEPTANCE CRITERIA Detection Test False Call Test Acceptance Critera Acceptance Criteria No. of No. of Maximum Flawed Minimum Unflawed Number Grading Detection Grading of False Units Criteria Units Calls 5 5 - l0 0 6 6 11 T 2~p 7 ~ ~ ~ 16 2^
9 7 105 2 10 8 29- 15 3 2 11 9 22- 17 3 12 9 24- 18 ) 3 13 10 2f- 20 4-3 14 10 28- 21 3 15 11 3e- 23 , 3 16 12 3R-24 4 17 12 34- 26 6-4 18 13 3M-27 7 4 19 13 3X-29 4 20 14 40- 30 8- 5