ML032930263
| ML032930263 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar, Sequoyah  |
| Issue date: | 10/15/2003 |
| From: | Burzynski M Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML032930263 (29) | |
Text
I-Tennessee Valley Authority, 1101 Market Street, Chattanooga, Tennessee 37402-2801 October 15, 2003 10 CFR 50.55a(a)(3)(i)
U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001 Gentlemen:
In the Matter of ) Docket Nos. 50-327 Tennessee Valley Authority ) 50-328 50-390 SEQUOYAH NUCLEAR PLANT (SQN) UNITS 1 AND 2, AND WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 - AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME) BOILER AND PRESSURE VESSEL CODE, SECTION XI, APPENDIX VIII, SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS, REQUEST FOR RELIEF PDI-3
Reference:
NRC Regulatory Issue Summary (RIS) 2003-01, Examination of Dissimilar Metal Welds, Supplement 10 to Appendix VIII of Section XI of the ASME Code, dated January 21, 2003 Pursuant to 10 CFR 50.55a(a)(3)(i), TVA requests relief from certain inservice inspection requirements in the ASME Boiler and Pressure Vessel Code in Section XI of the 1995 Edition through the 1996 Addenda (1995A96 Code) related to the ultrasonic examination of dissimilar metal welds at SQN and WBN. The enclosure to this letter contains a TVA generic relief request, PDI-3, to be applied to SQN Units 1 and 2 and WBN Unit 1. Similar requests for use with the Browns Ferry Nuclear Plant Units 1, 2, and 3, as requests for relief 1-ISI-16, 2-ISI-20, and 3-ISI-12, have been submitted to the NRC and were approved in a letter dated October 8, 2003.
The Final Rule, 64 FR 51370 [10 CFR 50.55a(g)(6)(ii)(C)], dated September 22, 1999, required utilities to implement a program to comply with ASME Section XI, Appendix VIII, Supplement 10, by November 22, 2002. Supplement 10 contains the qualification PFed on cycOWpor
U.S. Nuclear Regulatory Commission Page 2 October 15, 2003 requirements for procedures, equipment, and personnel involved with examining dissimilar metal (DSM) welds using ultrasonic techniques.
These supplemental requirements are commonly referred to as performance-based criteria for the improvement of the ability of an examiner to detect and characterize flaws during DSM examinations.
The objective of these criteria is to provide more reliable examination results.
As written, the requirements to Supplement 10 of the 1995A96 Code require changes in order to demonstrate the principles are in line with other supplements already being implemented. In this process, the industry has implemented a Performance Demonstration Initiative (PDI) program and has already developed a more practical alternative program to implement a degree of quality comparable to the requirements of Supplement 10. The alternative program has been submitted to the ASME Section XI for consideration and possible incorporation into the Code and was approved by the ASME Section XI Subcommittee on Nuclear Inservice Inspection in February 2003. Final ASME Code approval is pending. TVA has been a participant in the industry-sponsored program through the Nuclear Energy Institute and the Electric Power Research Institute (EPRI).
TVA will evaluate the implementation of the alternative program as it is approved in the future by the applicable ASME and regulatory actions.
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 the safe operation of SQN and WBN because the program is intended for use during outages when DSM weld examinations are to be performed. As described in NRC RIS 2003-01 (Reference), 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, Revision 1, "Information to Licensees Regarding NRC Inspection Manual Section on Resolution of Degraded and Nonconforming Conditions."
For SQN Units 1 and 2, and WBN Unit 1, there have been no DSM welds examined since November 22, 2002. However, DSM welds are scheduled for examination during the SQN Unit 1 and 2 Cycle 13 refueling outages (RFO) [fall 2004 and spring 2005, respectively] and during the WBN Unit 1, Cycle 6 RFO (spring 2005). TVA will submit additional relief requests for NRC approval if the required examination coverage and/or flaw characterizations are not achieved during the examinations in accordance with the alternative program.
U.S. Nuclear Regulatory Commission Page 3 October 15, 2003 The proposed alternative program described in the enclosed relief request for SQN Units 1 and 2, and WBN Unit 1 follows the scope of Supplement 10 with the enhancements, clarifications, and refinements as developed by the EPRI PDI program and approved by the ASME Section XI Subcommittee. This request closely follows the format and content of the Exelon Generation Company's and AmerGen Energy Company's relief request that was submitted in a letter dated March 26, 2003 and subsequently approved by NRC letter dated July 16, 2003. In addition, a similar request has been approved for Florida Power and Light's Turkey Point Units 3 and 4 in an NRC letter dated July 31, 2003. TVA's use of the PDI program and the enclosed proposed request provides an acceptable level of quality and safety pursuant to the requirements of 10 CFR 50.55a(a) (3)(i).
TVA requests approval of this relief request by August 20, 2004 to support resource planning for the SQN Unit 1, Cycle 13 (fall 2004)
RFO.
There are no new regulatory commitments in this letter. If you have any questions, please contact Rob Brown at (423) 751-7228.
Sincerely, ark. urzj Manag'e4 Nucleavr Licensing Enclosures cc (Enclosures):
Mr. Stephen J. Cahill, Chief U.S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth Street, SW, Suite 23T85 Atlanta, Georgia 30303-8931 cc: Continued on page 4
U.S. Nuclear Regulatory Commission Page 4 October 15, 2003 cc (Enclosures):
Mr. Michael L. Marshall, Jr., Project Manager U.S., Nuclear Regulatory Commission Mail Stop 08G9 One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852-2739 NRC Senior Resident Inspector Sequoyah Nuclear Plant U.S. Nuclear Regulatory Commission 2600 Igou Ferry Road Soddy Daisy, TN 37379 NRC Senior Resident Inspector U.S. Nuclear Regulatory Commission Watts Bar Nuclear Plant 1260 Nuclear Plant Road Spring City, TN 37381
ENCLOSURE TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT (SQN) UNITS 1 AND 2 AND WATTS BAR NUCLEAR PLANT (WBN) UNIT .
AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME) SECTION XI, APPENDIX VIII, SUPPLEMENT 10, QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS, GENERIC REQUEST FOR RELIEF - PDI-3 EXECUTIVE
SUMMARY
In accordance with 10 CFR 50.55a(a)(3)(i), TVA is requesting relief from certain impractical 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 through the NEI/EPRI committee meetings.
- 10CFR50.55a(g)(6)(ii)(C), "Implementation of Appendix VIII to Section XI,w 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:
These are 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."
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 1/3 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 inch (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 inch 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; the remainder shall be alternative flaws. Specimens with intergranular stress corrosion cracking (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.
- 2. Alternative flaw mechanisms shall have a tip width no more than 0.002 inches (.05 mm).
Note, that 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."
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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.
Mechanical fatigue crack i rrea l - nBase 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 indicates 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 units shall be at least 1-1/2 times the number of flawed grading units."
Technical Basis - Table VIII-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.
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4.
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 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 that is 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 E-5
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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 Paragraphs 2.3(a) and 2.3(b) states:
. . . 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 shown in the following attachment.
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 VIII-SlO-1.
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 attached matrix.
This attachment is a side-by-side and point-for-point comparison 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 the ASME Section XI Subcommittee and which 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.
Enforcement of all Supplement 10 requirements currently places TVA in the position of not being able to effectively demonstrate acceptable qualification of NDE personnel, equipment, and procedures for the examination of DSM welds. In response to this concern, TVA assisted PDI to develop the proposed alternatives with the intent of relying on the common approved industry procedures to achieve the basic principle of high quality E-6
ultrasonic examinations. In addition, these alternatives have been developed through industry consensus, they are well thought-out, and they are commensurate with their importance to the protection of the health and safety of the public.
IMPLEMNTATION SCHEDULE:
This alternative -is proposed for use for SQN Units 1 and 2, and WBN Unit 1 until the end of each unit's respective current ten-year ISI Program interval as follows:
SQN Units 1 and 2 are currently in the third period of their second program interval which began December 16, 1995 and ends December 15, 2005.
WBN Unit 1 is currently in the second period of the first ten-year interval which began May 27, 1996 and ends December 31, 2006. WBN's Cycle 6 refueling outage will be in the third period of the first ISI Program ten-year interval.
ATTACHENNT: 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
SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS f Currcnt Requiremcnt Proposed Change Reasoning 1.0 SCOPE Supplement 10 is applicable to A scope statement provides added dissimilar metal piping welds clarity regarding the applicable examined from either the inside or range of each individual outside surface. Supplement 10 is Supplement. The exclusion of CRC not applicable to piping welds provides consistency between containing supplemental corrosion Supplement 10 and the recent resistant clad (CRC) applied to revision to Supplement 2 (reference mitigate Intergranular Stress ASME Boiler and Pressure Vessel Corrosion Cracking (IGSCC). Code Committee File No. BC 00-755).
Note, an additional change identifying CRC as sin course of preparation, is being processed separately.
1.0 SPECIMEN REQUIREMENTS 2.0 SPECIMEN REQUIREMENTS Renumbered Qualification test specimens shall Qualification test specimens shall No Change meet the requirements listed meet the requirements listed herein, unless a set of specimens herein, unless a set of specimens is designed to accommodate specific is designed to accommodate specific limitations stated in the scope of limitations stated in the scope of the examination procedure (e.g., the examination procedure (e.g.,
pipe size, weld joint pipe size, weld joint configuration, access limitations). configuration, access limitations).
The same specimens may be used to The same specimens may be used to demonstrate both detection and demonstrate both detection and sizing qualification. sizing qualification.
1.1 General. The specimen set 2.1 General. The specimen set Renumbered shall conform to the following shall conform to the following requirements. requirements.
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SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS I1 Current Requirement Proposed Change Reasoning (a) The minimum number of flaws in New, changed minimum number of a specimen set shall be ten. flaws to 10 so sample set size for detection is consistent with length and depth-sizing.
(a) Specimens shall have sufficient (b) Specimens shall have sufficient Renumbered volume to minimize spurious volume to minimize spurious reflections that may interfere with reflections that may interfere with the interpretation process. the interpretation process.
(b) The specimen set shall include (c) The specimen set shall include Renumbered, metricated, the change the minimum and maximum pipe the minimum and maximum pipe in pipe diameter tolerance provides diameters and thicknesses for which diameters and thicknesses for which consistency between Supplement 10 the examination procedure is the examination procedure is and the recent revision to applicable. Pipe diameters within applicable. Pipe diameters within Supplement 2 (Reference BC 00-755).
a range of 0.9 to 1.5 times a 1/2 inches (13 mm) of the nominal nominal diameter shall be diameter shall be considered considered equivalent. Pipe equivalent. Pipe diameters larger diameters larger than 24 inches than 24 inches (610 mm) shall be shall be considered to be flat. considered to be flat. When a When a range of thicknesses is to range of thicknesses is to be be examined, a thickness tolerance examined, a thickness tolerance of of +25 percent is acceptable. +25 percent is acceptable.
(c) The specimen set shall include (d) The specimen set shall include Renumbered, changed "condition" to examples of the following examples of the following "conditions."
fabrication condition: fabrication conditions:
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SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS 4I Current Requirement Proposed Change Reasoning (1) geometric conditions that (1) geometric and material Clarification, some of the items normally require discrimination conditions that normally require listed relate to material from flaws (e.g., counterbore or discrimination from flaws (e.g., conditions rather than geometric weld root conditions, cladding, counterbore or weld root conditions. Weld repair areas were weld buttering, remnants of conditions, cladding, weld added as a result of recent field previous welds, adjacent welds in buttering, remnants of previous experiences.
close proximity); welds, adjacent welds in close proximity, weld repair areas);
(2) typical limited scanning (2) typical limited scanning Differentiates between ID and OD surface conditions (e.g., surface conditions shall be scanning surface limitations.
diametrical shrink, single-side included as follows: Requires that ID and OD access due to nozzle and safe end (a) for outside surface qualifications be conducted external tapers). examination, weld crowns, independently (Note, new paragraph diametrical shrink, single-side 2.0 (identical to old paragraph access due to nozzle and safe end 1.0] provides for alternatives when external tapers la set of specimens is designed to (b) for inside surface examination, accommodate specific limitations internal tapers, exposed weld stated in the scope of the roots, and cladding conditions for examination procedure.)
inside surface examinations).
(e) Qualification requirements shall be satisfied separately for outside surface and inside surface examinations.
(d) All flaws in the specimen set Deleted this requirement, because shall be cracks. new paragraph 2.3 below provides for the use of "alternative flaws in lieu of cracks.
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SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning (1) At least 50 percent of the 2.2 Flaw Location. Renumbered and retitled. Flaw cracks shall be in austenitic At least 80 percent of the flaws location percentages redistributed material. At least 50 percent of shall be contained wholly in weld because field experience indicates the cracks in austenitic material or buttering material. At least that flaws contained in weld or shall be contained wholly in weld one and no more than 10 percent of buttering material are probable and or buttering material. At least 10 the flaws shall be in ferritic base represent the more stringent percent of the cracks shall be in material. At least one and no more ultrasonic detection scenario.
ferritic material. The remainder than 10 percent of the flaws shall of the cracks may be in either be in austenitic base material.
austenitic or ferritic material.
(2) At least 50 percent of the 2.3 Flaw Type. Renumbered and retitled.
cracks in austenitic base material (a) At least 60 percent of the Alternative flaws are required for shall be either IGSCC or thermal flaws shall be cracks, and the placing axial flaws in the heat fatigue cracks. At least 50 remainder shall be alternative affected zone (HAZ) of the weld and percent of the cracks in ferritic flaws. Specimens with IGSCC shall other areas where implantation of a material shall be mechanically or be used when available. crack produces metallurgical thermally induced fatigue cracks. Alternative flaws shall meet the conditions that result in an following requirements: unrealistic ultrasonic response.
(1) Alternative flaws, if used, This is consistent with the recent shall provide crack-like reflective revision to Supplement 2 (Reference characteristics and shall only be BC 00-755).
used when implantation of cracks would produce spurious reflectors The 40 percent limit on alternative that are uncharacteristic of flaws is needed to support the service-induced flaws. requirement for up to 70 percent (2) Alternative flaws shall have a axial flaws. Metricated.
tip width no more than 0.002 inches
(.05 mm).
(3) At least 50 percent of the (b) At least 50 percent of the Renumbered. Due to inclusion of cracks shall be coincident with flaws shall be coincident with "alternative flaws,, use of areas described in (c) above. areas described in 2.1(d) above. "cracksw is no longer appropriate.
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SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning 2.4 Flaw Depth. Moved from old paragraph 1.3(c) and All flaw depths shall be greater 1.4 and retitled. Consistency than 10 percent of the nominal pipe between detection and sizing wall thickness. Flaw depths shall specimen set requirements (e.g., 20 exceed the nominal clad thickness percent vs. 1/3 flaw depth when placed in cladding. Flaws in increments, e.g., original the sample set shall be distributed paragraph 1.3[c]).
as follows:
Flaw Depth Minimum
(% Wall Thickness) Number of Flaws 10-30% 20%
31-60% 20%
61-100% 20%
At least 75 percent of the flaws shall be in the range of 10 to 60 percent of wall thickness.
1.2 Detection Specimens. The Renumbered and retitled and moved specimen set shall include to paragraph 3.1(a). No other detection specimens that meet the changes.
following requirements.
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SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requiremcnt Proposed Change Reasoning (a) Specimens shall be divided into Renumbered to paragraph 3.1(a)(1).
grading units. Each grading unit No other changes.
shall include at least 3 inches of weld length. If a grading unit is designed to be unflawed, at least 1 inch 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 Moved to new paragraph 3.1(a)(2).
selected from Table VIII-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 Flaw depth requirements moved to the following criteria for flaw new paragraph 2.4, flaw orientation depth, orientation, and type. requirements moved to new paragraph 2.5, flaw type requirements moved to new paragraph 2.3, "Flaw Type.'
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SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change l Reasoning (1) All flaw depths shall be Deleted, for consistency in sample greater than 10 percent of the sets the depth distribution is the nominal pipe wall thickness. At same for detection and sizing.
least 1/3 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. 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 percent of the nominal pipe wall thickness.
(2) At least 30 percent and no more 2.5 Flaw Orientation. Note, this distribution is than 70 percent of the flaws, (a) For other than sizing specimens applicable for detection and depth-rounded to the next higher whole at least 30 percent and no more sizing. Paragraph 2.5(b)(1) number, shall be oriented axially. than 70 percent of the flaws, requires that all length-sizing The remainder of the flaws shall be rounded to the next higher whole flaws be oriented circumferentially.
oriented circumferentially. number, shall be oriented axially.
The remainder of the flaws shall be oriented circumferentially.
1.3 Length-sizing Specimens. The Renumbered and retitled and moved specimen set shall include length- to new paragraph 3.2 sizing specimens that meet the following requirements.
(a) All length-sizing flaws shall Moved, included in new paragraph be oriented circumferentially. 3.2(a).
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SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning (b) The minimum number of flaws Moved, included in new paragraph shall be ten. 2.1 above.
(c) All flaw depths shall be Moved, included in new paragraph greater than 10 percent of the 2.4 above after revision for nominal pipe wall thickness. At consistency with detection least 1/3 of the flaws, rounded to distribution.
the next higher whole number, shall have depths between 10 percent and 30 percent 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 percent of the nominal pipe wall thickness.
1.4 Depth-Sizing Specimens. The Moved, included in new paragraphs specimen set shall include 2.1, 2.3, and 2.4.
depth-sizing specimens that meet the following requirements.
(a) The minimum number of flaws Moved, included in new paragraph shall be ten. 2.1.
(b) Flaws in the sample set shall Moved, potential conflict with old not be wholly contained within paragraph 1.2(c)(1); "However, flaw cladding and shall be distributed depths shall exceed the nominal as follows: clad thickness when placed in cladding.' Revised for clarity and included in new paragraph 2.4.
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Il SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR I#
METAL PIPING WELDS Current Requirement Proposed Change Reasoning Flaw Depth Minimum Moved, included in paragraph 2.4
(% Wall Thickness) Number of for consistent applicability to Flaws detection and 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 Added for clarity.
the following requirements.
(1) Length-sizing flaws shall be Moved from old paragraph 1.3(a).
oriented circumferentially.
(2) Depth-sizing flaws shall be Included for clarity. Previously oriented as in 2.5(a). addressed by omission (i.e.,
length, but not depth had a specific exclusionary statement).
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SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS f Current Requirement PrpsdChange Reasoning 2.0 CONDUCT OF PERFORMANCE 3.0 PERFORMANCE DEMONSTRATION Renumbered DEMONSTRATION The specimen inside surface and Personnel and procedure performance Differentiate between identification shall be concealed demonstration tests shall be qualifications conducted from the from the candidate. All conducted according to the outside and inside surface.
examinations shall be completed following requirements:
prior to grading the results and (a) For qualifications from the presenting the results to the outside surface, the specimen candidate. Divulgence of inside surface and identification particular specimen results or shall be concealed from the candidate viewing of unmasked candidate. When qualifications are specimens after the performance performed from the inside surface, demonstration is prohibited. 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.
2.1 Detection Test. Flawed and 3.1 Detection Qualification. Renumbered, moved text to paragraph unflawed grading units shall be l3.1(a)(3).
randomly mixed.-
(a) The specimen set shall include Renumbered, moved from old detection specimens that meet the paragraph 1.2.
following requirements:
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SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR I METAL PIPING WELDS Current Requirement Proposed Change Reasoning (1) Specimens shall be divided into Renumbered, moved from old grading units. paragraph 1.2(a). Metricated. No (a) Each grading unit shall include other changes.
at least 3 inches (76 mm) of weld length.
(b)The end of each flaw shall be separated from an unflawed grading unit by at least 1 inch (25 mm) of unflawed material. A flaw may be less than 3 inches 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 Moved from old paragraph 1.2(b).
demonstration detection test sets Table revised to reflect a change shall be selected from Table VIII- in the minimum sample set to 10 and S10-1. The number of unflawed the application of equivalent grading units shall be at least statistical false call parameters 1-1/2 times the number of flawed to the reduction in unflawed grading units. grading units. Human factors due to large sample size.
(3) Flawed and unflawed grading Moved from old paragraph 2.1.
units shall be randomly mixed.
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SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS t Current Requirement Proposed Change Reasoning (b) Examination equipment and Moved from old paragraph 3.1.
personnel are qualified for Modified to reflect the 100 percent detection when personnel detection acceptance criteria of demonstrations satisfy the procedures versus personnel and acceptance criteria of Table VIII- equipment contained in new S10-1 for both detection and false paragraph 4.0 and the use of 1.5X calls. 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 (a) Each reported circumferential Provides consistency between conducted separately or in flaw in the detection test shall be Supplement 10 and the recent conjunction with the detection length-sized. revision to Supplement 2 (Reference test. 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 (b) When the length-sizing test is Change made to ensure security of conducted in conjunction with the conducted in conjunction with the samples, consistent with the recent detection test, and less than ten detection test, and less than ten revision to Supplement 2 (Reference circumferential flaws are detected, circumferential flaws are detected, BC 00-755).
additional specimens shall be additional specimens shall be provided to the candidate such that provided to the candidate such that Note, length and depth-sizing use at least ten flaws are sized. The at least ten flaws are sized. The the term "regions' while detection regions containing a flaw to be regions containing a flaw to be uses the term "grading units.d The sized shall be identified to the sized may be identified to the two terms define different concepts candidate. The candidate shall candidate. The candidate shall and are not intended to be equal or determine the length of the flaw in determine the length of the flaw in interchangeable.
each region. each region.
(c) For a separate length-sizing (c) For a separate length-sizing Change made to ensure security of test, the regions of each specimen test, the regions of each specimen samples, consistent with the recent containing a flaw to be sized shall containing a flaw to be sized may revision to Supplement 2 (Reference be identified to the candidate. be identified to the candidate. BC 00-755).
The candidate shall determine the The candidate shall determine the length of the flaw in each region. length of the flaw in each region.
(d) Examination procedures, Moved from old paragraph 3.2(a),
equipment, and personnel are includes inclusion of "when' as an qualified for length-sizing when editorial change. Metricated.
the RMS error of the flaw length measurements, as compared to the true flaw lengths, does not exceed 0.75 inches (19 mm).
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SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS . I Current Requirement Proosed ChanG e Reasoning 2.3 Depth-Sizing Test 3.3 Depth-Sizing Test Renumbered (a) For the depth-sizing test, 80 (a) The depth-sizing test may be Change made to ensure security of percent of the flaws shall be sized conducted separately or in samples, consistent with the recent at a specific location on the conjunction with the detection revision to Supplement 2 (Reference surface of the specimen identified test. For a separate depth-sizing BC 00-755).
to the candidate. 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 (b) When the depth-sizing test is Change made to be consistent with regions of each specimen containing conducted in conjunction with the the recent revision to Supplement 2 a flaw to be sized shall be detection test, and less than ten (Reference BC 00-755).
identified to the candidate. The flaws are detected, additional candidate shall determine the specimens shall be provided to the Changes made to ensure security of maximum depth of the flaw in each candidate such that at least ten samples, consistent with the recent region. flaws are sized. The regions of revision to Supplement 2 (Reference each specimen containing a flaw to BC 00-755).
be sized may be identified to the candidate. The candidate shall determine the maximum depth of the flaw in each region.
(c) Examination procedures, Moved from old paragraph 3.2(b).
equipment, and personnel are Metricated.
qualified for depth-sizing when the RMS error of the flaw depth measurements, as compared to the true flaw depths, does not exceed 0.125 inches (3 mm).
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SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning 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),
Examination procedures, equipment, reference changed to Table S10 from and personnel are qualified for S2 because of the change in the detection when the results of the minimum number of flaws and the performance demonstration satisfy reduction in unflawed grading units the acceptance criteria of Table from 2X to 1.5X.
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, Moved to new paragraph 3.2(d),
equipment, and personnel are included word "when" as an qualified for length-sizing the editorial change.
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, Moved to new paragraph 3.3(c).
equipment, 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 inches.
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I4 SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR METAL PIPING WELDS Current Requirement Proposed Change Reasoning 4.0 PROCEDURE QUALIFICATION New Procedure qualifications shall New. Based on experience gained in include the following additional conducting qualifications, the requirements: equivalent of 3 personnel sets (a) The specimen set shall include (i.e., a minimum of 30 flaws) is the equivalent of at least three required to provide enough flaws to personnel performance demonstration adequately test the capabilities of test sets. Successful personnel the procedure. Combining performance demonstrations may be successful demonstrations allows combined to satisfy these a variety of examiners to be used requirements: to qualify the procedure.
(b) Detectability of all flaws in Detectability of each flaw within the procedure qualification test the scope of the procedure is set that are within the scope of required to ensure an acceptable the procedure shall be personnel pass rate. The last demonstrated. Length and depth- sentence is equivalent to the sizing shall meet the requirements previous requirements and is of paragraph 3.1, 3.2, and 3.3. satisfactory for expanding the (c) At least one successful essential variables of a previously personnel demonstration shall be qualified procedure.
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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V.
SUPPLEMENT 10 - QUALIFICATION REQUIREMENTS FOR DISSIMILAR II METAL PIPING WELDS Current Requirement Proposed Chan Reasoning TABLE VIII- -
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 Detectlon Grading of False Units Criteria Units Calls
.1 .
6 6 1 7 6 14 1 8 ~ ~7 16 2 9 i 10 2 10 8 15 2 11 9 2217 33 12 9 -18 33 13 10 26-20 3 14 10 -21 53 15 11 30-23 5-3 16 12 3e-24 6-4 17 12 S4-26 6-4 18 13 3-274 19 13 "-29 4 20 14 40-30 8-5 EA- 17