ML031690248
| ML031690248 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 06/16/2003 |
| From: | Abney T Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML031690248 (25) | |
Text
June 16, 2003 10 CFR 50.55a(a)(3)(i)
U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Stop: OWFN P1-35 Washington, D.C. 20555-0001 Gentlemen:
In the Matter of ) Docket Nos. 50-259 Tennessee Valley Authority ) 50-260 50-296 BROWNS FERRY NUCLEAR PLANT (BFN) - UNITS 1, 2, AND 3 - AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME) SECTION XI, APPENDIX VIII, SUPPLEMENT 10, QUALIFICATION REQUIREMENTS FOR DISSIMILIAR METAL PIPING WELDS - REQUESTS FOR RELIEF 1-ISI-17, 2-ISI-20, AND 3-ISI-16
Reference:
NRC Regulatory Issue Summary 2003-01, Examination of Dissimilar Metal Welds, Supplement 10 to Appendix VIII of Section XI of the ASME Code, dated January 21, 2003.
In accordance with 10 CFR 50.55a(a)(3)(i), TVA is requesting relief from certain inservice inspection (ISI) requirements in Section XI of the ASME Boiler and Pressure Vessel Code related to the ultrasonic examination of dissimiliar metal welds at BFN.
The enclosure to this letter contains BFN Units 1, 2, and 3 requests for relief 1-ISI-17, 2-ISI-20, and 3-ISI-16 for NRC review and approval.
The Final Rule, 64 FR 51370 [10 CFR 50.55a(g)(6)(ii)(C)], dated September 22, 1999, required TVA to implement a program to comply with ASME Section XI, Appendix VIII, Supplement 10 by November 22, 2002. Supplement 10 contains the qualification requirements for procedures, equipment, and personnel involved with examining dissimiliar metal (DSM) welds using ultrasonic
U.S. Nuclear Regulatory Commission Page 2 June 16, 2003 examination techniques. This scope is commonly referred as performance based criteria to improve the ability of an examiner to detect and characterize flaws during examination of components to provide more reliable examination results.
As described in NRC RIS 2003-01 (Reference), the NRC has concluded that facilities that do not have a program that implements Supplement 10 to Appendix VIII of Section XI of the ASME Code are noncompliant with 10 CFR 50.55a(g)(6)(ii)(C), irrespective of when the actual examination of dissimiliar metal welds must be conducted. The inability to meet the 10 CFR 50.55a(g)(6)(ii)(C) required schedule of November 22, 2002, to have a Supplement 10 program in place has not impacted safe operation of BFN because the program is intended for use during an outage for DSM weld examinations. Until regulatory compliance is achieved, any system operability issues arising from the inability to comply with Appendix VIII, Supplement 10 will be addressed consistent with Generic Letter 91-18.
The industry has implemented a Performance Demonstration Initiative (PDI) program and has developed an alternative program to implement Supplement 10. The alternative program has been submitted to the ASME Section XI for consideration and was approved by the ASME Section XI Subcommittee in February 2003.
Final ASME Code approval is pending. TVA is a participant in the industry-sponsored program through the Nuclear Energy Institute and EPRI.
TVA will submit additional relief requests for NRC approval if the required examination coverage and/or flaw characterizations (i.e.,
sizing) are not achieved during the examinations in accordance with the alternative program. Additional relief requests, if required, would be submitted within 90 days of restart from the refueling outage in which the examinations were performed.
The proposed alternative program described in the enclosed relief requests for BFN Units 1, 2, and 3 follow the scope of Supplement 10, with the enhancements, clarifications, and refinements as approved by the ASME Section XI Subcommittee and provides an acceptable level of quality and safety in accordance with 10 CFR 50.55a(a)(3)(i).
U.S. Nuclear Regulatory Commission Page 3 June 16, 2003 For BFN Units 1, 2, and 3 there have been no DSM welds examined since November 22, 2002. However, there are two DSM welds scheduled for examination during the BFN Unit 3, Cycle 11 refueling outage (Spring 2004). TVA requests approval of this relief request by January 16, 2004, to support resource planning for the Unit 3, Cycle 11 (Spring 2004) refueling outage.
There are no new regulatory commitments in this letter. If you have any questions, please contact me at (256) 729-2636.
Sincerely, Original signed by:
T. E. Abney Manager of Licensing and Industry Affairs Enclosures cc (Enclosures):
(Via NRC Electronic Distribution)
Mr. Stephen J. Cahill, Branch Chief U.S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth Street, SW, Suite 23T85 Atlanta, Georgia 30303-8931 NRC Resident Inspector Browns Ferry Nuclear Plant 10833 Shaw Road Athens, Alabama 35611-6970 Mr. Kahtan N. Jabbour, Senior Project Manager U.S. Nuclear Regulatory Commission One White Flint, North (MS 08G9) 11555 Rockville Pike Rockville, Maryland 20852-2739
U.S. Nuclear Regulatory Commission Page 4 June 16, 2003 DTL:JWD:BAB Enclosures cc (Enclosures):
A. S. Bhatnagar, PAB 1E-BFN M. J. Burzynski, BR 4X-C A. L. Ladd, PEC-2A-BFN J. E. Maddox, LP 6A-C D. C. Olcsvary, LP 6A-C C. M. Root, PAB 1G-BFN J. R. Rupert, NAB 1A-C K. W. Singer, LP 6A-C M. D. Skaggs, POB 2C-BFN E. J. Vigluicci, ET 11A-K R. E. Wiggall, SAB 1A-BFN NSRB Support, LP 5M-C EDMS-K s:\lic\submit\subs\Unit 1, 2, & 3 RR Dissimiliar Metal Welds.w95
ENCLOSURE TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNITS 1, 2, AND 3 AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME) SECTION XI, APPENDIX VIII, SUPLEMENT 10, QUALIFICATION REQUIREMENTS FOR DISSIMILIAR METAL PIPING WELDS, REQUESTS FOR RELIEF 1-ISI-17, 2-ISI-20, AND 3-ISI-16 (See Attached)
TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNITS 1, 2, AND 3 AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME) SECTION XI, APPENDIX VIII, SUPLEMENT 10, QUALIFICATION REQUIREMENTS FOR DISSIMILIAR METAL PIPING WELDS, REQUESTS FOR RELIEF 1-ISI-17, 2-ISI-20, AND 3-ISI-16 EXECUTIVE
SUMMARY
In accordance with 10 CFR 50.55a(a)(3)(i), TVA is requesting relief from inservice inspection requirements of the 1995 Edition through the 1996 Addenda of Section XI, Appendix VIII, Supplement 10*, Qualification Requirements For Dissimilar Metal Piping Welds, of the ASME Boiler and Pressure Vessel Code. The Performance Demonstration Initiative (PDI) Program for implementing the Supplement 10 qualification program for dissimilar metal welds is not in strict compliance with the requirements of Supplement 10 of the 1995 Edition through the 1996 Addenda. TVA proposes to use the PDI Program for implementation of Appendix VIII, Supplement 10 as amended in the Attachment of this enclosure. The amendments to Supplement 10 as shown in the Attachment were coordinated with PDI, and the NRC.
- 10CFR50.55a(g)(6)(ii)(C) Implementation of Appendix VIII to Section XI, mandates that all nuclear power plants comply with Section XI, Division 1, 1995 Edition with the 1996 Addenda to implement the requirements of Supplement 10, beginning November 22, 2002.
SYSTEM/COMPONENT(S) FOR WHICH RELIEF IS REQUESTED:
Pressure Retaining Piping Welds subject to examination using procedures, personnel, and equipment qualified to ASME Section XI, Appendix VIII, Supplement 10 criteria.
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.
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Item 2 - Paragraph 1.1(d) states - All flaws in the specimen set shall be cracks.
Item 3 - Paragraph 1.1(d)(1) states - At least 50 percent of the cracks shall be in austenitic material. At least 50 percent of the cracks in austenitic material shall be contained wholly in weld or buttering material. At least 10 percent 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 in part - 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 l/3 of the flaws, rounded to the next higher whole number, shall have depths between 10 percent and 30 percent of the nominal pipe wall thickness. Paragraph 1.4(b) distribution table requires 20 percent of the flaws to have depths between 10 percent and 30 percent.
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.
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 percent 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.
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RELIEF REQUESTED:
Relief is requested to use the following alternative requirements for implementation of Appendix VIII, Supplement 10 requirements.
The alternative requirements will be implemented through the PDI Program.
A copy of the proposed revision to Supplement 10 is attached.
It identifies the proposed alternatives and allows them to be viewed in context. It also identifies additional clarifications and enhancements for information. The proposed revisions to Supplement 10 have been submitted to the ASME Section XI for consideration and were approved by the ASME Section XI Subcommittee in February 2003. Final ASME Code approval is pending.
BASIS FOR RELIEF:
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 1/2 inches (13 mm) of the nominal diameter shall be considered equivalent. Pipe diameters larger than 24 inches (610 mm) shall be considered to be flat.
When a range of thicknesses is to be examined, a thickness tolerance of +25 percent is acceptable.
Technical Basis - The change in the minimum pipe diameter tolerance from 0.9 times the diameter to within 1/2 inches of the nominal diameter 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 Supplement 2.
Item 2 - The proposed alternative to Paragraph 1.1(d) states:
At least 60 percent of the flaws shall be cracks, and the remainder shall be alternative flaws. Specimens with IGSCC shall be used when available. Alternative flaws, shall meet the following requirements:
(1) Alternative flaws, if used, shall provide crack-like reflective characteristics and shall only be used when implantation of cracks would produce spurious reflectors that are uncharacteristic of service-induced flaws.
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(2) Alternative flaws shall have a tip width no more than 0.002 inches (.05 mm).
Note, 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.
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 percent 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.
Excavation Mechanical fatigue crack area in Base material Item 3 - The proposed alternative to Paragraph 1.1(d)(1) states:
At least 80 percent of the flaws shall be contained wholly in weld or buttering material. At least one and no more than 10 percent of the flaws shall be in ferritic base material. At least one and no more than 10 percent of the flaws shall be in austenitic base material.
Technical Basis - Under the current Code, as few as 25 percent of the flaws are contained in austenitic weld or buttering material.
Recent experience has indicated that flaws contained within the weld are the likely scenarios. 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:
Personnel performance demonstration detection test sets shall be selected from Table VIII-S10-1. The number of unflawed grading E-5
units shall be at least 1-1/2 times the number of flawed grading units.
Technical Basis - Table S10-1 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 from the human factors perspective. 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 VIII-S10-1.
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%
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 percent of the flaws shall be in the range of 10 to 60 percent 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 E-6
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. This is consistent with the recent revision to Supplement 2.
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. This is consistent with the recent revision to Supplement 2.
Items 9 and 10 - The proposed alternative 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. This is consistent with the recent revision to Supplement 2. It also incorporates terminology from length sizing for additional clarity.
Item 11 - The proposed alternative modifies the acceptance criteria of Table VIII-S2-1 as follows:
Technical Basis - The proposed alternative is identified as new Table S10-1 (see attachment). It was modified to reflect the reduced number of unflawed grading units and allowable false calls. As a part of ongoing Code activities, Pacific Northwest National Laboratory has reviewed the statistical significance of these revisions and offered the revised Table S10-1.
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ALTERNATIVE EXAMINATION:
In lieu of the requirements of ASME Section XI, 1995 Edition, 1996 Addenda, Appendix VIII, Supplement 10, the proposed alternative shall be used. The proposed alternative is described in the enclosure (Attachment).
The Attachment is a juxtaposition of the ASME Section XI, 1995 Edition with the 1996 Addenda, Appendix VIII, Supplement 10 requirements and the proposed changes to Supplement 10 that have been approved by ASME Section XI Subcommittee and form the basis for relief outlined above.
JUSTIFICATION FOR GRANTING RELIEF:
Pursuant to 10 CFR 50.55a(a)(3)(i), approval is requested to use the proposed alternatives described above in lieu of the ASME Section XI, Appendix VIII, Supplement 10 requirements.
Compliance with the proposed alternatives will provide an adequate level of quality and safety for examination of the affected welds.
IMPLEMENTATION SCHEDULE:
This alternative will be used for BFN Units 1, 2, and 3 until the end of each units respective current ten-year ISI interval as follows:
BFN Unit 1 is currently in the third period of the first interval which extends from August 1, 1974 until 1-year after restart from the current extended outage.
BFN Unit 2 is currently in the first period of the third ten-year interval which extends from May 25, 2001 through May 24, 2011.
BFN Unit 3 is currently in the third period of the second ten-year interval which extends from November 19, 1996 through November 18, 2005.
ATTACHMENT: Table listing the proposed alternative to ASME Section XI, 1995 Edition, 1996 Addenda, Appendix VIII, Supplement 10.
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Attachment Supplement 10 - Qualification Requirements For Dissimilar Metal Piping Welds Proposed Amendments E-9
SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning 1.0 SCOPE Supplement 10 is applicable to dissimilar metal A scope statement provides added clarity regarding piping welds examined from either the inside or the applicable range of each individual Supplement.
outside surface. Supplement 10 is not applicable The exclusion of CRC provides consistency between to piping welds containing supplemental Supplement 10 and the recent revision to corrosion resistant clad (CRC) applied to Supplement 2 (Reference BC 00-755). Note, an mitigate Intergranular Stress Corrosion additional change identifying CRC as in course of Cracking (IGSCC). preparation is being processed separately.
1.0 SPECIMEN REQUIREMENTS 2.0 SPECIMEN REQUIREMENTS Renumbered Qualification test specimens shall meet the Qualification test specimens shall meet the No Change requirements listed herein, unless a set of specimens requirements listed herein, unless a set of specimens is designed to accommodate specific limitations is designed to accommodate specific limitations stated in the scope of the examination procedure stated in the scope of the examination procedure (e.g., pipe size, weld joint configuration, access (e.g., pipe size, weld joint configuration, access limitations). The same specimens may be used to limitations). The same specimens may be used to demonstrate both detection and sizing qualification. demonstrate both detection and sizing qualification.
1.1 General. The specimen set shall conform to the 2.1 General. Renumbered following requirements. The specimen set shall conform to the following requirements.
(a) The minimum number of flaws in a specimen New, changed minimum number of flaws to 10 so set shall be ten. sample set size for detection is consistent with length and depth sizing.
(a) Specimens shall have sufficient volume to (b) Specimens shall have sufficient volume to Renumbered minimize spurious reflections that may interfere minimize spurious reflections that may interfere with the interpretation process. with the interpretation process.
(b) The specimen set shall include the minimum (c) The specimen set shall include the minimum Renumbered, metricated, the change in pipe and maximum pipe diameters and thicknesses for and maximum pipe diameters and thicknesses for diameter tolerance provides consistency between which the examination procedure is applicable. which the examination procedure is applicable. Supplement 10 and the recent revision to Pipe diameters within a range of 0.9 to 1.5 times a Pipe diameters within 1/2 in. (13 mm) of the Supplement 2 (Reference BC 00-755) nominal diameter shall be considered equivalent. nominal diameter shall be considered equivalent.
Pipe diameters larger than 24 in. shall be considered Pipe diameters larger than 24 in. (610 mm) shall be to be flat. When a range of thicknesses is to be considered to be flat. When a range of thicknesses examined, a thickness tolerance of +25% is is to be examined, a thickness tolerance of +25% is acceptable. acceptable.
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SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning (c) The specimen set shall include examples of the (d) The specimen set shall include examples of the Renumbered, changed condition to conditions following fabrication condition: following fabrication conditions:
(1) geometric conditions that normally require (1) geometric and material conditions that Clarification, some of the items listed relate to discrimination from flaws (e.g., counterbore or weld normally require discrimination from flaws (e.g., material conditions rather than geometric root conditions, cladding, weld buttering, remnants counterbore or weld root conditions, cladding, weld conditions. Weld repair areas were added as a of previous welds, adjacent welds in close buttering, remnants of previous welds, adjacent result of recent field experiences.
proximity); welds in close proximity, weld repair areas);
(2) typical limited scanning surface conditions (e.g., (2) typical limited scanning surface conditions shall Differentiates between ID and OD scanning surface diametrical shrink, single-side access due to nozzle be included as follows: limitations. Requires that ID and OD qualifications and safe end external tapers). (a) for outside surface examination, weld crowns, be conducted independently (Note, new paragraph diametrical shrink, single-side access due to nozzle 2.0 (identical to old paragraph 1.0) provides for and safe end external tapers alternatives when a set of specimens is designed to (b) for inside surface examination, internal accommodate specific limitations stated in the scope tapers, exposed weld roots, and cladding of the examination procedure.).
conditions for inside surface examinations).
(e) Qualification requirements shall be satisfied separately for outside surface and inside surface examinations.
(d) All flaws in the specimen set shall be cracks. Deleted this requirement, because new 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 austenitic 2.2 Flaw Location. Renumbered and re-titled. Flaw location material. At least 50% of the cracks in austenitic At least 80% of the flaws shall be contained wholly percentages redistributed because field experience material shall be contained wholly in weld or in weld or buttering material. At least one and no indicates that flaws contained in weld or buttering buttering material. At least 10% of the cracks shall more than 10% of the flaws shall be in ferritic base material are probable and represent the more be in ferritic material. The remainder of the cracks material. At least one and no more than 10% of stringent ultrasonic detection scenario.
may be in either austenitic or ferritic material. the flaws shall be in austenitic base material.
(2) At least 50% of the cracks in austenitic base 2.3 Flaw Type. Renumbered and re-titled. Alternative flaws are material shall be either IGSCC or thermal fatigue (a) At least 60% of the flaws shall be cracks, and required for placing axial flaws in the HAZ of the cracks. At least 50% of the cracks in ferritic the remainder shall be alternative flaws. weld and other areas where implantation of a crack material shall be mechanically or thermally induced Specimens with IGSCC shall be used when produces metallurgical conditions that result in an fatigue cracks. available. Alternative flaws shall meet the unrealistic ultrasonic response. This is consistent following requirements: with the recent revision to Supplement 2 (Reference (1) Alternative flaws, if used, shall provide crack- BC 00-755).
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SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning like reflective characteristics and shall only be used when implantation of cracks would produce The 40% limit on alternative flaws is needed to spurious reflectors that are uncharacteristic of support the requirement for up to 70% axial flaws.
service-induced flaws. Metricated (2) Alternative flaws shall have a tip width no more than 0.002 in. (.05 mm).
(3) At least 50% of the cracks shall be coincident (b) At least 50% of the flaws shall be coincident Renumbered. Due to inclusion of alternative with areas described in (c) above. with areas described in 2.1(d) above. flaws, use of cracks is no longer appropriate.
2.4 Flaw Depth.
All flaw depths shall be greater than 10% of the Moved from old paragraph 1.3(c) and 1.4 and re-nominal pipe wall thickness. Flaw depths shall titled. Consistency between detection and sizing exceed the nominal clad thickness when placed in specimen set requirements (e.g., 20% vs. 1/3 flaw cladding. Flaws in the sample set shall be depth increments, e.g., original paragraph 1.3(c))
distributed as follows:
Flaw Depth Minimum
(% Wall Thickness) Number of Flaws 10-30% 20%
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 set shall Renumbered and re-titled and moved to paragraph include detection specimens that meet the following 3.1(a). No other changes requirements.
(a) Specimens shall be divided into grading units. Renumbered to paragraph 3.1(a)(1). No other Each grading unit shall include at least 3 in. of weld changes.
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 E-12
SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning another grading unit. Grading units need not be uniformly spaced around the pipe specimen.
(b) Detection sets shall be selected from Table VIII- Moved to new paragraph 3.1(a)(2).
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 following Flaw depth requirements moved to new paragraph criteria for flaw depth, orientation, and type. 2.4, flaw orientation requirements moved to new paragraph 2.5, flaw type requirements moved to new paragraph 2.3, Flaw Type.
(1) All flaw depths shall be greater than 10% of the Deleted, for consistency in sample sets the depth nominal pipe wall thickness. At least 1/3 of the distribution is the same for detection and sizing.
flaws, rounded to the 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 the 2.5 Flaw Orientation. Note, this distribution is applicable for detection and flaws, rounded to the next higher whole number, (a) For other than sizing specimens at least 30% depth sizing. Paragraph 2.5(b)(1) requires that all shall be oriented axially. The remainder of the and no more than 70% of the flaws, rounded to the length- sizing flaws be oriented circumferentially.
flaws shall be oriented circumferentially. next higher whole number, shall be oriented axially.
The remainder of the flaws shall be oriented circumferentially.
1.3 Length Sizing Specimens. The specimen set Renumbered and re-titled and moved to new shall include length sizing specimens that meet the paragraph 3.2 following requirements.
(a) All length sizing flaws shall be oriented Moved, included in new paragraph 3.2(a) circumferentially.
(b) The minimum number of flaws shall be ten. Moved, included in new paragraph 2.1 above (c) All flaw depths shall be greater than 10% of the Moved, included in new paragraph 2.4 above after nominal pipe wall thickness. At least l/3 of the revision for consistency with detection distribution flaws, rounded to the next higher whole number, E-13
SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning 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 specimen set Moved, included in new paragraphs 2.1, 2.3, 2.4 shall include depth sizing specimens that meet the following requirements.
(a) The minimum number of flaws shall be ten. Moved, included in new paragraph 2.1 (b) Flaws in the sample set shall not be wholly Moved, potential conflict with old paragraph contained within cladding and shall be distributed 1.2(c)(1); However, flaw depths shall exceed the as follows: nominal clad thickness when placed in cladding..
Revised for clarity and included in new paragraph 2.4 E-14
SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning Moved, included in paragraph 2.4 for consistent Flaw Depth Minimum applicability to detection and sizing samples.
(% Wall Thickness) Number of Flaws 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 following Added for clarity requirements.
(1) Length-sizing flaws shall be oriented Moved from old paragraph 1.3(a) circumferentially.
(2) Depth sizing flaws shall be oriented as in Included for clarity. Previously addressed by 2.5(a). omission (i.e., length, but not depth had a specific exclusionary statement) 2.0 CONDUCT OF PERFORMANCE 3.0 PERFORMANCE DEMONSTRATION Renumbered DEMONSTRATION The specimen inside surface and identification shall Personnel and procedure performance Differentiate between qualifications conducted from be concealed from the candidate. All examinations demonstration tests shall be conducted according the outside and inside surface.
shall be completed prior to grading the results and to the following requirements.
presenting the results to the candidate. Divulgence (a) For qualifications from the outside surface, of particular specimen results or candidate viewing the specimen inside surface and identification of unmasked specimens after the performance shall be concealed from the candidate. When demonstration is prohibited. qualifications are performed from the inside surface, the flaw location and specimen identification shall be obscured to maintain a blind test. All examinations shall be completed prior to grading the results and presenting the results to the candidate. Divulgence of particular specimen results or candidate viewing of unmasked specimens after the performance demonstration is prohibited.
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SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning 2.1 Detection Test. Flawed and unflawed grading 3.1 Detection Test. Renumbered, moved text to paragraph 3.1(a)(3) units shall be randomly mixed (a) The specimen set shall include detection Renumbered, moved from old paragraph 1.2.
specimens that meet the following requirements.
(1) Specimens shall be divided into grading units. Renumbered, moved from old paragraph 1.2(a).
(a) Each grading unit shall include at least 3 in. (76 Metricated. No other changes.
mm) of weld length.
(b)The end of each flaw shall be separated from an unflawed grading unit by at least 1 in. (25 mm) of unflawed material. A flaw may be less than 3 in. in length.
(c) The segment of weld length used in one grading unit shall not be used in another grading unit.
(d) Grading units need not be uniformly spaced around the pipe specimen.
(2) Personnel performance demonstration detection Moved from old paragraph 1.2(b). Table revised to test sets shall be selected from Table VIII-S10-1. reflect a change in the minimum sample set to 10 The number of unflawed grading units shall be at and the application of equivalent statistical false call least 1-1/2 times the number of flawed grading parameters to the reduction in unflawed grading units. units.
Human factors due to large sample size.
(3) Flawed and unflawed grading units shall be Moved from old paragraph 2.1 randomly mixed.
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SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning (b) Examination equipment and personnel are Moved from old paragraph 3.1. Modified to reflect qualified for detection when personnel the 100% detection acceptance criteria of demonstrations satisfy the acceptance criteria of procedures versus personnel and equipment Table VIII S10-1 for both detection and false calls. contained in new paragraph 4.0 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 Table VIII-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 the Provides consistency between Supplement 10 and separately or in conjunction with the detection test. detection test shall be length-sized. the recent revision to Supplement 2 (Reference BC 00-755).
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SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning (b) When the length-sizing test is conducted in Change made to ensure security of samples, (b) When the length sizing test is conducted in conjunction with the detection test, and less than ten consistent with the recent revision to Supplement 2 conjunction with the detection test, and less than ten circumferential flaws are detected, additional (Reference BC 00-755).
circumferential flaws are detected, additional specimens shall be provided to the candidate such specimens shall be provided to the candidate such that at least ten flaws are sized. The regions Note, length and depth sizing use the term that at least ten flaws are sized. The regions containing a flaw to be sized may be identified to regions while detection uses the term grading containing a flaw to be sized shall be identified to the candidate. The candidate shall determine the units. The two terms define different concepts and the candidate. The candidate shall determine the length of the flaw in each region. are not intended to be equal or interchangeable.
length of the flaw in each region.
(c) For a separate length-sizing test, the regions of Change made to ensure security of samples, (c) For a separate length sizing test, the regions of each specimen containing a flaw to be sized may be consistent with the recent revision to Supplement 2 each specimen containing a flaw to be sized shall be identified to the candidate. The candidate shall (Reference BC 00-755).
identified to the candidate. The candidate shall determine the length of the flaw in each region.
determine the length of the flaw in each region.
(d) Examination procedures, equipment, and Moved from old paragraph 3.2(a) includes inclusion personnel are qualified for length-sizing when the of when as an editorial change.
RMS error of the flaw length measurements, as Metricated.
compared to the true flaw lengths, do not exceed 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 flaws shall (a) The depth-sizing test may be conducted Change made to ensure security of samples, be sized at a specific location on the surface of the separately or in conjunction with the detection consistent with the recent revision to Supplement 2 specimen identified to the candidate. test. For a separate depth-sizing test, the regions (Reference BC 00-755).
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 each (b) When the depth-sizing test is conducted in Change made to be consistent with the recent specimen containing a flaw to be sized shall be conjunction with the detection test, and less than revision to Supplement 2 (Reference BC 00-755).
identified to the candidate. The candidate shall ten flaws are detected, additional specimens shall determine the maximum depth of the flaw in each be provided to the candidate such that at least Changes made to ensure security of samples, region. ten flaws are sized. The regions of each specimen consistent with the recent revision to Supplement 2 E-18
SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning containing a flaw to be sized may be identified to (Reference BC 00-755).
the candidate. The candidate shall determine the maximum depth of the flaw in each region.
(c) Examination procedures, equipment, and Moved from old paragraph 3.2(b). Metricated.
personnel are qualified for depth sizing when the RMS error of the flaw depth measurements, as compared to the true flaw depths, do not exceed 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. Examination Moved to new paragraph 3.1(b), reference changed procedures, equipment, and personnel are qualified to Table S10 from S2 because of the change in the for detection when the results of the performance minimum number of flaws and the reduction in demonstration satisfy the acceptance criteria of unflawed grading units from 2X to 1.5X.
Table VIII-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, and Moved to new paragraph 3.2(d), included word personnel are qualified for length sizing the RMS when as an editorial change.
error of the flaw length measurements, as compared to the true flaw lengths, is less than or equal to 0.75 in.
(b) Examination procedures, equipment, and Moved to new paragraph 3.3(c) 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.
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SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning 4.0 PROCEDURE QUALIFICATION New Procedure qualifications shall include the New. Based on experience gained in conducting following additional requirements. qualifications, the equivalent of 3 personnel sets (a) The specimen set shall include the equivalent (i.e., a minimum of 30 flaws) is required to provide of at least three personnel performance enough flaws to adequately test the capabilities of demonstration test sets. Successful personnel the procedure. Combining successful performance demonstrations may be combined to demonstrations allows a variety of examiners to be satisfy these requirements. used to qualify the procedure. Detectability of each (b) Detectability of all flaws in the procedure flaw within the scope of the procedure is required to qualification test set that are within the scope of ensure an acceptable personnel pass rate. The last the procedure shall be demonstrated. Length sentence is equivalent to the previous requirements and depth sizing shall meet the requirements of and is satisfactory for expanding the essential paragraph 3.1, 3.2, and 3.3. variables of a previously qualified procedure (c) At least one successful personnel demonstration shall be performed.
(d) To qualify new values of essential variables, at least one personnel qualification set is required. The acceptance criteria of 4.0(b) shall be met.
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SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning 10 TABLE VIII-S2-1 PERFORMANCE DEMONSTRATION DETECTION TEST ACCEPTANCE CRITERIA Detection Test False Call Test Acceptance Criteria Acceptance Criteria No. of Flawed Minimum No. of Unflawed Maximum Number Grading Units Detection Grading Units of False Calls Criteria 5 5 10 0 6 6 12 1 7 6 14 1 8 7 16 2 9 7 18 2 10 8 20 15 3 2 11 9 22 17 3 3 12 9 24 18 3 3 13 10 26 20 4 3 14 10 28 21 5 3 15 11 30 23 5 3 16 12 32 24 6 4 17 12 34 26 6 4 18 13 36 27 7 4 19 13 38 29 7 4 20 14 40 30 8 5 E-21