DCL-13-021, Performance Demonstration Initiative (POI) Program Alternatives and Their Bases with Respect to ASME Code Section Xi, Appendix Viii Supplement 11 Requirements
| ML13078A293 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 03/05/2013 |
| From: | Pacific Gas & Electric Co |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML130780374 | List: |
| References | |
| DCL-13-021 | |
| Download: ML13078A293 (10) | |
Text
Enclosures 3 and 4 contain Proprietary Information
-Withhold Under 10 CFR 2.390 Enclosure 2 PG&E Letter DCL-13-021 Performance Demonstration Initiative (POI) Program Alternatives and their Bases with Respect to ASME Code Section XI, Appendix VIII Supplement 11 Requirements Appendix VIII, Supplement 11 POI Modification 1.0 SPECIMEN REQUIREMENTS 1.1 General (b) The specimen set shall consist Modification: (b) The specimen set of at least three specimens shall consist of at least three specimens having different nominal pipe having different nominal p'ipe diameters diameters and overlay and overlay thicknesses.
They shall thicknesses.
They shall include the minimum and maximum include the minimum and nominal pipe diameters for which the maximum nominal pipe examination procedure is applicable.
diameters for which the Pipe diameters within a range of 0.9 to examination procedure is 1.5 times a nominal diameter shall be applicable.
Pipe diameters considered equivalent.
If the procedure within a range of 0.9 to 1.5 is applicable to pipe diameters of 24 times a nominal diameter shall inches or larger, the specimen set must be considered equivalent.
If include at least one specimen 24 inches the procedure is applicable to or larger but need not include the pipe diameters of 24 inches or maximum diameter.
larger, the specimen set must include at least one specimen 24 inches or larger but need The specimen set shall include not include the maximum specimens with overlays not thicker than diameter.
The specimen set 0.1 inches more than the minimum must include at least one thickness, nor thinner than 0.25 inches of specimen with overlay the maximum nominal overlay thickness thickness within -0.1 inches to for which the examination procedure is +0.25 inches of the maximum applicable. nominal overlay thickness for which the procedure is Basis: To avoid confusion, the overlay applicable.
thickness tolerance contained in the last sentence was reworded and the phrase "and the remainder shall be alternative flaws" was added to the next to last sentence in paragraph 1.1 (d) (1). (d) Flaw Conditions (1) Base metal flaws. All flaws Modification:
(1) Base metal flaws. All must be cracks in or near the flaws must be in or near the butt weld butt weld heat-affected zone, heat-affected zone, open tQ the inside 1 Enclosures 3 and 4 contain Proprietary Information When separated from Enclosures 3 and 4 , this document is decontrolled.
Enclosures 3 and 4 contain Proprietary Information
-Withhold Under 10 CFR 2.390 Enclosure 2 PG&E Letter DCL-13-021 Appendix VIII, Supplement 11 POI Mod i fication open to the inside surface, an d surface, and extending a t least 75% extending at least 75% through through the base metal wall. I nten t ional the base metal wall. Flaws overlay fabrication flaws shall not may extend 100% through the interfere with ultrasonic detection or base metal and into the characterization of the base metal flaws. overlay material; in this case, Specimens containing IGSCC shall be intentional overlay fabrication used when available.
At least 70% of the flaws shall not interfere with flaws in the detection and sizing tests ultrasonic detection or shall be cracks and the remainder shall characterization of the be alternative flaws. Alternative flaw cracking.
Specimens mechanisms, if used, shall provide crack-containing IGSCC shall be like reflective characteristics and shall be used when available.
limited 'by the following: (a) The use of alternative flaws shall be limited to when the implantation of cracks produces spurious reflectors that are uncharacteristic of actual flaws. (b) Flaws shall be semi elliptical with a tip width of less than or equal to 0.002 inches. Basis: This paragraph requires that all base metal flaws be cracks. Implanting a crack requires excavation of the base material on at least one side of 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.
To resolve this issue, the PDI program revised this paragraph to allow use of alternative flaw mechanisms under controlled conditions.
For example, alternative flaws shall be limited to when implantation of cracks precludes obtaining an effective ultrasonic response, flaws shall be semi elliptical 2 Enclosures 3 and 4 contain Proprietary Information When separated from Enclosures 3 and 4, this document is decontrolled.
Enclosures 3 and 4 contain Proprietary Information
-Withhold Under 10 CFR 2.390 Enclosure 2 PG&E Letter DCL-13-021 Appendix VIII, Supplement 11 POI Modification with a tip width of less than or equal to 0.002 inches, and at least 70% of the flaws in the detection and sizing test shall be cracks and the remainder shall be alternative flaws. To avoid confusion, the overlay thickness tolerance contained in paragraph 1.1 (b), last sentence, was reworded and the phrase "and the remainder shall be alternative flaws" was added to the next to last sentence.
Paragraph 1.1 (d)(1) includes the statement that intentional overlay fabrication flaws shall not interfere with ultrasonic detection or characterization of the base metal flaws. (e) Detection Specimens (1) At least 20% but less than Modification:
(1) At least 200/0 but less 40 0/0 of the flaws shall be than 40% of the base metal flaws shall oriented within degrees of be oriented within +/-20 degrees of the the pipe axial direction.
The pipe axial direction.
The remainder shall remainder shall be oriented be oriented circumferentially.
Flaws shall circumferentially. Flaws shall not be open to any surface to which the not be open to any surface to candidate has physical or visual access. which the candidate has physical or visual access. The rules of IWA-3300 shall be Basis: The requirement for axially used to determine whether oriented overlay fabrication flaws was closely spaced flaws should be excluded from the POI Program as an treated as single or multiple improbable scenario.
Weld overlays are flaws. typically applied using automated GTAW t e chniqu e s with the filler m e ta l applied in a circumferential direct i on. Because resultant fabrication induced discontinuities would also be expected to have major dimensions oriented in the circumferential direction axial overlay fabrication flaws are unrealistic.
The requirement for using IWA-3300 for proximity flaw evaluation was excluded, instead indications will be sized based on their individual merits. (2) Specimens shall be divided Modification:
(2) Specimens shall be 3 Enclosures 3 and 4 contain Proprietary Information When separated from Enclosures 3 and 4 , this document is decontrolled.
Enclosures 3 and 4 contain Proprietary Information
-Withhold Under 10 CFR 2.390 Enclosure 2 PG&E Letter OCL-13-021 Appendix VIII, Supplement 11 POI Mod i f i cat i on into base and overlay g r ading divided into base metal and overlay units. Each specimen shall fabrication grading units. Each specime n contain one or both types of shall contain one or both types of grading grading units. units. Flaws shall not interfere with ultrasonic detection or characterization of other flaws. (a)(1) A base grading unit shall Modificatio n: (a)(1) A base metal include at least 3 inches of the grading unit includes the overlay material length of the overlaid weld. and the outer 250/0 of the original overlaid The base grading unit includes weld. The base metal grading unit shall the outer 250/0 of the overlaid extend circumferentially for at least 1 inch weld and base metal on both and shall start at the weld centerline and sides. The base grading unit be wide enough in the axial direction to shall not include the inner 75% encompass one half of the original weld of the overlaid weld and base crown and a minimum of 0.50 inch of the metal overlay material, or base adjacent base material.
metal-to-overlay interface.
Basis: The phrase "and base metal on both sides," was inadvertently included in the description of a base metal grading unit. The POI program intentionally excludes this requirement because some of the qualification samples include flaws on both sides of the weld. To avoid confusion several instances of the term "cracks" or "cracking" were changed to the term "flaws" because of the use of alternative flaw mechanisms. Modified to require that a base metal grading unit include at least 1 inch of the length of the overlaid weld, rather than 3 inches. (a)(2) When base metal Modification: (a)(2) When base metal cracking penetrates into the flaws penetrate into the overlay material, overlay material, the base the base metal grading unit shall not be grading unit shall include the used as part of any overlay fabrication overlay metal within 1 inch of grading unit. the crack location.
This portion of the overlay material shall not be used as part of any overlay 4 Enclosures 3 and 4 contain Proprietary Information When separated from Enclosures 3 and 4 , this document is decontrolled.
Enclosures 3 and 4 contain Proprietary Information
-Withhold Under 10 CFR 2.390 Enclosure 2 PG&E Letter DCL-13-021 Appendix VIII, Supplement 11 POI Modification grading unit. (a)(3) When a base grading Modification: (a)(3) Sufficient unflawed unit is designed to be overlaid weld and base metal shall exist unflawed, at least 1 inch of on all sides of the grading unit to unflawed overlaid weld and preclude interfering reflections from base metal shall exist on either adjacent flaws. side of the base grading unit. The segment of weld length used in one base grading unit Basis: Modified to require sufficient shall not be used in another unflawed overlaid weld and base metal to base grading unit. Base exist on all sides of the grading unit to grading units need not be preclude interfering reflections from. uniformly spaced around the adjacent flaws, rather than the 1 inch specimen.
requirement. (b)(1) An overlay grading unit Modification: (b)( 1) An overlay shall include the overlay fabrication grading unit shall include the material and the base metal-overlay material and the base metal-to-to-overlay interface of at least overlay interface for a length of at least 6 square inches. The overlay 1 inch. grading unit shall be rectangular, with minimum dimensions of 2 inches. Basis: Modified to require sufficient unflawed overlaid weld and base metal to exist on all sides of the grading unit to preclude interfering reflections from adjacent flaws, rather than the 2 inch requirement. (b )(2) An overlay grading unit Modification: (b)(2) Overlay fabrication designed to be unflawed shall grading units designed to be unflawed be surrounded by unflawed shall be separated by unflawed overlay overlay material and unflawed material and unflawed base base metal-to-overlay interface metal-to-overlay interface for at least 1 for at least 1 inch around its inch at both ends. Sufficient unflawed entire perimeter.
The specific overlaid weld and base metal shall exist area used in one overlay on both sides of the overlay fabrication grading unit shall not be used grading unit to preclude interfering in another overlay grading unit. reflections from adjacent flaws. The Overlay grading units need not specific area used in one overlay be spaced uniformly about the fabrication gradinQ unit shall not be used 5 Enc l osures 3 and 4 cont ai n Proprietary Information When separated from Enclosures 3 and 4, this document is decontrolled.
Enclosures 3 and 4 contain Proprietary Information
-Withhold Under 10 CFR 2.390 Enclosure 2 PG&E Letter DCL-13-021 Appendix VIII, Supplement 11 POI Modification specimen.
in another overlay fabrication grading unit. Overlay fabrication grading units need not be spaced uniformly about the specimen.
Basis: Paragraph 1.1 (e)(2)(b)(2) states that overlay fabrication grading units designed to be unflawed shall be separated by unflawed overlay material and unflawed base metal-to-overlay interface for at least 1 inch at both ends, rather than around its entire perimeter. (b )(3) Detection sets shall be Modification: (b)(3) Detection sets shall selected from Table VIII-S2-1.
be selected from Table VIII-S2-1.
The The minimum detection minimum detection sample set is five sample set is five flawed base flawed base metal grading units, ten grading units, ten unflawed unflawed base metal grading units, five base grading units, five flawed flawed overlay fabrication grading units, overlay grading units, and ten and ten unflawed overlay fabrication unflawed overlay grading units. grading units. For each type of grading For each type of grading unit, unit, the set shall contain at least twice as the set shall contain at least many unflawed as flawed grading units. twice as many unflawed as For initial procedure qualification, flawed grading units. detection sets shall include the equivalent of three personnel qualification sets. To qualify new values of essential variables, at least one personnel qualification set is required.
6 Enclosures 3 and 4 contain Proprietary Information When separated from Enclosures 3 and 4, this document is decontrolled.
Enclosures 3 and 4 contain Proprietary Information
-Withhold Under 10 CFR 2.390 Enclosure 2 PG&E Letter DCL-13-021 Appendix VIII, Supplement 11 POI Modification (f) Sizing Specimen (1) The minimum number of Modification:
(1) The minimum number flaws shall be ten. At least 300/0 of flaws shall be ten. At least 300/0 of the of the flaws shall be overlay flaws shall be overlay fabrication flaws. fabrication flaws. At least 40% At least 400/0 of the flaws shall be open to of the flaws shall be cracks the inside surface. Sizing sets shall . open to the inside surface. contain a distribution of flaw dimensions to assess sizing capabilities.
For initial procedure qualification, sizing sets shall include the equivalent of three personnel qualification sets. To qualify new values of essential variables, at least one personnel qualification set is required. (3) Base metal cracking used Modification:
(3) Base metal flaws used for length sizing demonstrations for length sizing demonstrations shall be shall be oriented oriented circumferentially.
circumferentially.
(4) Depth sizing specimen sets Modification:
(4) Depth sizing specimen shall include at least two distinct sets shall include at least two distinct locations where cracking in the locations where a base metal flaw base metal extends into the extends into the overlay material by at overlay material by at least least 0.1 inch in the through-wall 0.1 inch in the through-wall direction.
direction.
2.0 CONDUCT OF PERFORMANCE DEMONSTRATION The specimen inside surface and Modification:
The specimen inside identification shall be concealed surface and identification shall be from the candidate.
All concealed from the candidate.
All examinations shall be completed examinations shall be completed prior to prior to grading the results and grading the results and presenting the presenting the results to the results to the candidate.
Divulgence of candidate.
Divulgence of particular particular specimen results or candidate specimen results or candidate viewing of unmasked specimens after the viewing of unmasked specimens performance demonstration is prohibited.
after the performance The overlay fabrication flaw test and the demonstration is prohibited.
base metal flaw test may be performed separately.
2.1 Detection Test Flawed and unflawed grading units Modification:
Flawed and unflawed shall be randomly mixed. Although grading units shall be randomly mixed. 7 Enclosures 3 and 4 contain Proprietary Information When separated from Enclosures 3 and 4, this document is decontrolled.
Enclosures 3 and 4 contain Proprietary Information
-Withhold Under 10 CFR 2.390 2 PG&E Letter DCL-13-021 Appendix VIII, Supplement 11 POI Modification the boundaries of specific grading Although the boundaries of specific units shall not be revealed to the grading units shall not be revealed to the candidate, the candidate shall be candidate, the candidate shall be made made aware of the type or types of aware of the type or types of grading grading units (base or overlay) that units (base metal or overlay fabrication) are present for each specimen.
that are present for each specimen.
2.2 Length Sizing Test (d) For flaws in base grading Modification: (d) For flaws in base units, the candidate shall metal grading units, the candidate shall estimate the length of that part estimate the length of that part of the flaw of the flaw that is in the outer that is in the outer 250/0 of the base metal 25% of the base wall thickness.
wall thickness.
2.3 Depth Sizing Test For the depth sizing test, 80% of Modification:
the flaws shall be sized at a (a) The depth sizing test may be specific location on the su rface of conducted separately or in conjunction the specimen identified to the with the detection test. candidate.
For the remaining flaws, the regions of each (b) When the depth sizing test is specimen containing a flaw to be conducted in conjunction with the sized shall be identified to the detection test and the detected flaws do candidate.
The candidate shall not satisfy the requirements of 1.1 (f), determine the maximum depth of additional specimens shall be provided to the flaw in each region. the candidate.
The regions containing a flaw to be sized shall be identified to the candidate.
The candidate shall determine the maximum depth of the flaw in each region. (c) For a separate depth sizing test, the regions of each specimen containing a flaw to be sized shall be identified to the candidate.
The candidate shall determine the maximum depth of the flaw in each region. 8 Enclosures 3 and 4 contain Proprietary Information When separated from Enclosures 3 and 4, this document is decontrolled.
Enclosures 3 and 4 contain Proprietary Information
-Withhold Under 10 CFR 2.390 Enclosure 2 PG&E Letter DCL-13-021 App e ndix VIII , Supplement 11 3.0 ACCEPTANCE CRITERI A 3.1 Detection Acceptance Criteria Examination procedures, equipment, and personnel are qualified for detection when the results of the performance demonstration satisfy the acceptance criteria of Table VIII-S2-1 for both detection and false calls. The criteria shall be satisfied separately by the demonstration results for base grading units and for overlay grading units. 3.2 Sizing Acceptance Criteria (a) The RMS error of the flaw length measurements, as compared to the true flaw lengths, is less than or equal to 0.75 inch. The length of base metal cracking is measured at the 750/0 through-base-metal position. (b) All extensions of base metal cracking into the overlay material by at least 0.1 inch are POI Modification Modification:
Examination procedures are qualified for detection when: (a) All flaws within the scope of the procedure are detected and the results of the performance demonstration satisfy the acceptance criteria o f Table VIII-S2-1 for false calls. (b) At least one successful personnel demonstration has been performed meeting the acceptance criteria defined in (c). (c) Examination equipment and personnel are qualified for detection when the results of the performance demonstration satisfy the acceptance criteria of Table VIII-S2-1 for both detection and false calls. (d) The criteria in (b) and (c) shall be satisfied separately by the demonstration results for base metal grading units and for overlay fabrication grading units. Modification: (a) The RMS error of the flaw length measurements, as compared to the true flaw lengths, is less than or equal to 0.75 inch. The length of base metal flaws is measured at the 750/0 through-base-metal position.
Modification:
This requirement is omitted. 9 Enclosures 3 and 4 contain Proprietary Information When separated from Enclosures 3 and 4 , this document is decontrolled.
Enclosures 3 and 4 contain Proprietary Information
-Withhold Under 10 CFR 2.390 Enclosure 2 PG&E Letter OCL-13-021 Appendix VIII, Supplement 11 POI Modification reported as being intrusions Basis: The requirement for reporting all into the overlay material.
extensions of cracking into the overlay is omitted from the POI Program because it i s redundant to the RMS calculations performed in paragraph 3.2(c) and its presence adds confusion and ambiguity to depth sizing as required by paragraph 3.2(c). This also makes the weld overlay program consistent with the supplement 2 depth sizing criteria.
10 Enclosures 3 and 4 contain Proprietary Information When separated from Enclosures 3 and 4 , this document is decontrolled.