1CAN100702, Request for Alternative ANO1-R&R-011, Proposed Alternative to ASME Code Requirements for Weld Overlay Repairs

Request for Alternative ANO1-R&R-011, Proposed Alternative to ASME Code Requirements for Weld Overlay Repairs

ML072910042
Person / Time
Site:	Arkansas Nuclear
Issue date:	10/08/2007
From:	James D Entergy Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
1CAN100702
Download: ML072910042 (54)

Text

Entergy Operations, Inc.

1448 SaR 333 Russellville. AR 72802 Tel 479-858A4619 Dale E. James Manager, Licensing Nuclear Safety Assurance Arkansas Nuclear One 1 CAN 100702 October 8, 2007 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555

REFERENCE:

Request for Alternative ANO1 -R&R-01 1 Proposed Alternative to ASME Code Requirements for Weld Overlay Repairs Arkansas Nuclear One, Unit 1 Docket No. 50-313 License No. DPR-51 Entergy Letter to the NRC dated March 22, 2007, Request for Alternative ANO1-R&R-010 - Proposed Alternative to ASME Code Requirements for Weld Overlay Repairs

Dear Sir or Madam:

Pursuant to 10 CFR 50.55a(a)(3)(i), Entergy Operations, Inc. (Entergy) hereby requests approval of a proposed alternative to the requirements of ASME Code,Section XI, Subsection IWA-4000 for mitigating primary water stress corrosion cracking (PWSCC) on dissimilar metal welds using full structural weld overlays for Arkansas Nuclear One, Unit 1 (ANO-1). This request, as described in Enclosure 1, is based on ASME Code Case N-740 and is applicable to ANO-1.

The request is based on the referenced ANO-1 request, which was approved by the NRC on April 6, 2007.

In accordance with 10 CFR 50.55a(a)(3)(i), proposed alternatives to the aforementioned requirements may be approved by the NRC provided an acceptable level of quality and. safety are maintained. Entergy believes the proposed alternative meets this requirement.

There are new commitments contained in this letter, as described in Enclosure 2.

Entergy requests approval of the proposed request for alternative by October 1, 2008, in order to support the fall 2008 refueling outage. Although this request is neither exigent nor emergency, your prompt review is requested.

A-0`47

1 CAN 100702 Page 2 of 2 If you have any questions or require additional information, please contact David Bice at 479-858-5338.

Sincerely, D EJ/d b Encl sures:

1.

Request for Alternative ANO1-R&R-01 1......

Dissimilar Metal Weld Details and Figures Proposed Alternative for Preemptive Full Structural Weld Overlays Proposed Ambient Temperature Temperbead Technique Comparison of ASME Code Case N-504-2 and Appendix Q of ASME Section XI with the Proposed Alternative of Attachment 2 for Preemptive Full Structural Weld Overlays Technical Basis for Alternatives to ASME Code Case N-638-1, Ambient Temperature Temperbead Welding Comparison of ASME Section XI Appendix VIII, Supplement 11 to Performance Demonstration Initiative (PDI)

2.

List of Regulatory Commitments cc:

Mr. Elmo E. Collins Regional Administrator U. S. Nuclear Regulatory Commission Region IV Office 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064 NRC Senior Resident Inspector Arkansas Nuclear One P. 0. Box 310 London, AR 72847 U. S. Nuclear Regulatory Commission Attn: Mr. Alan B. Wang MS 0-7 D1 Washington, DC 20555-0001 Mr. Bernard R. Bevill Director Division of Radiation Control and Emergency Management Arkansas Department of Health & Human Services P.O. Box 1437 Slot H-30 Little Rock, AR 72203-1437 1CAN100702 Request for Alternative AN01 -R&R-01 1 to 1 CAN 100702 Page 1 of 14 ENTERGY OPERATIONS, INC.

Arkansas Nuclear One, Unit 1 REQUEST FOR ALTERNATIVE ANO1 -R&R-01 1 Proposed Alternative in Accordance with 10 CFR 50.55a(a)(3)(i)

--Alternative Provides Acceptable Level of Quality and Safety--

SI.

ASME CODE COMPONENTS AFFECTED Components:

Code Class:

References:

ISI Weld 17-017 Hot Leg "A" (CCA-1-36') Nozzle Dissimilar Metal Weld to Decay Heat Piping (CCA-8-12")

1.

ASME Code,Section XI, 2001 Edition / 2003 Addenda except as listed in Reference 2

2.

ASME Section XI, 2001 Edition to be used for Appendix VIII, "Perforrhance Demonstration for Ultrasonic Examination Systems"

3.

USAS B31.7, 1968 Edition, June 1968 Errata (Original Construction Code for Surge Line and Hot Leg Piping)

4.

ASME Section III, Subsection NB, 1989 Edition

5.

CEP-ISI-002, ANO-1 Inservice Inspection Plan

6.

EPRI Report 1011898, Justification for the Removal of the 100 Square Inch Temperbead Weld Repair Limitation

7.

EPRI Report GC-1 11050, Ambient Temperature Preheat for Machine GTA W Temperbead Applications.

8.

EPRI Report 1006696, Crack Growth Rates for Evaluating PWSCCC of Alloy 82, 182, and 132 Welds (MRP-1 15)

9.

EPRI Report 1013558, Temper Bead Welding Applications -

48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> Hold for Ambient Temperature Temper Bead Welding

10. ASME Code Case N-740

11.

ASME Code Case N-504-2

12.

ASME Code Case N-638-1 Arkansas Nuclear One, Unit 1 (ANO-1) I Fourth (4th) 10-Year Interval Unit / Inspection Interval Applicability:

to 1 CAN 100702 Page 2 of 14 II.

APPLICABLE CODE REQUIREMENT NOTE:

This request is applicable to weld overlay activities scheduled for the fall 2008 refueling outage (1 R21) at ANO-1. As of the submittal date of this request, ANO-1 is in the final period of its third 10-Year Inservice Inspection (ISI) interval. However, prior to 1R21, ANO-1 will have begun its fourth 10-Year ISI interval and updated to the 2001 Edition / 2003 Addenda of ASME Section XI (Reference 1) for repair/replacement activities and the 2001 Edition of ASME Section XI (Reference 2) for performance demonstration of ultrasonic examination systems. Therefore, this request is based on the Edition/Addenda of ASME Section XI applicable to the fourth 10-Year ISI interval.

The ASME Code (Code),Section XI, Subsections IWA-4411 and IWA-4520(a) require that repair/replacement activities be performed and examined in accordance with the Owner's Requirements and the original Construction Code of the component or system. Alternatively, Subsections IWA-441 1(a) and (b) allow use of later Editions/Addenda of the Construction Code (or a later different Construction Code such as ASME Section III) and revised Owner Requirements. Subsections IWA-441 1(e) and IWA-4600(b) provide alternative welding methods when the requirements of Subsection IWA-4411 cannot be met. Subsection IWA-4530(a) requires the performance of preservice examinations based on Subsection IWB-2200 for Class 1 components. Table IWB-2500, Category B-J, prescribes inservice inspection requirements for Class 1 butt welds in piping. Appendix VIII, Supplement 11 of ASME Section XI specifies performance demonstration requirements for ultrasonic examination of weld overlays.

III.

REASON FOR PROPOSED ALTERNATIVE Primary water stress corrosion cracking (PWSCC) of Alloy 600 components and welds has become a growing concern in the nuclear industry over the past decade. In particular, dissimilar metal welds (DMWs) made with Nickel Alloy 82 and 182 weld metal exposed to elevated operating temperatures are believed to pose a heightened propensity to PWSCC. Due to this concern, Entergy Operations, Inc. (Entergy) has concluded that the application of a preemptive full structural weld overlay for the "A" reactor coolant system (RCS) hot leg connection to the decay heat piping DMW is the most appropriate course of-action to ensure continued RCS pressure boundary integrity and enhance performance of future inspections.

Structural weld overlays have been used for several years on piping of both boiling water reactors (BWRs) and pressurized water reactors (PWRs) to arrest the growth of existing flaws while establishing a new structural pressure boundary. Notwithstanding the above, no evidence of PWSCC has' been found in the "A" hot leg to decay heat piping DMW. However, PWSCC is difficult to detect except when the inspection is performed in accordance with the rigorous requirements of ASME Section XI, Appendix VIII. The subject DMW has been evaluated and does not meet the surface or geometric requirements of Appendix VIII. Therefore, inspection of this weld cannot be performed to Appendix VIII requirements without modifying the weld geometry or configuration.

to 1CAN100702 Page 3 of 14 Effective May 31, 2008, ANO-1 will begin performing repair/replacement activities in accordance with the 2001 Edition / 2003 Addenda of ASME Section XI, except as described in Reference 2.

This edition of ASME Section XI does not include requirements for application of a preemptive, full structural weld overlay. Moreover, preemptive full structural weld overlay requirements are not presently included in any Edition/Addenda of ASME Section XI (including Code Cases) approved by the NRC.

Weld overlays have been applied as repairs to other plants in accordance with ASME Code Cases N-504-2 and N-638-1, which are "conditionally accepted" for use in Regulatory Guide (RG) 1.147. Application of these code cases to nozzle DMWs requires a series of relief requests since Code Case N-504-2 was written specifically for stainless steel pipe-to-pipe welds and Code Case N-638-1 contains some restrictions and requirements that are not applicable to weld overlays. Code Case N-740 has been approved by the ASME Code Committee to specifically address weld overlays on DMWs. Code Case N-740 also incorporates changes to the latest approved version of Code Case N-638 (i.e., N-638-3). However, Code Case N-740 does not specifically address preemptive weld overlays and has not yet been accepted by the NRC in RG 1.147.

This request for alternative is specific to the "A" hot leg nozzle to decay heat piping DMW. The carbon steel (P-No. 1) hot leg nozzle is welded to an austenitic stainless steel (P-No. 8) elbow.

The weld joining the nozzle to elbow is an 82/182-DMW (see Attachment 1 for additional details). The full structural weld overlay will be applied by deposition of Alloy 52M (ERNiCrFe-7A) weld metal on the outside surface of the DMW and adjacent base material.

IV.

PROPOSED ALTERNATIVE Pursuant to 10 CFR 50.55a(a)(3)(i), Entergy proposes the following as alternatives to the Code requirements specified in Section 3 above. The proposed alternatives are applicable to the DMW joining the decay heat piping to the "A" hot leg nozzle identified in Section 4 above.

A.

Install a preemptive full structural weld overlay in accordance with the proposed alternatives specified in Attachments 2 and 3. These alternatives are based on the methodology of ASME Section X1 Code Case N-740.

" Attachment 2 specifies an alternative applicable to the design, fabrication, examination, pressure testing, and inservice inspection of preemptive full structural weld overlays.

" Attachment 3 specifies an alternative applicable to ambient temperature temperbead welding. Attachment 3 will be applied as an alternative to the post-weld heat treatment requirements of ASME Section II1.

B.

Perform ultrasonic examinations of the proposed preemptive full structural weld overlays in accordance with Appendix VIII, Supplement 11 of the 2001 Edition / No Addenda of ASME Section X1 except as modified by the Performance Demonstration Initiative (PDI)

Program. The proposed PDI alternatives to Appendix VIII, Supplement 11 are specified in Attachment 6.

to 1CAN100702 Page 4 of 14 V.

BASIS FOR PROPOSED ALTERNATIVE A.

Proposed Alternative for Preemptive Structural Weld Overlays Entergy intends to install a preemptive full structural weld overlay to the DMW (Inconel 82/182) identified in Section 4 of this request in accordance with the proposed alternative of. A tabular comparison of the proposed alternative of Attachment 2 with Code Case N-504-2 and Appendix Q of ASME Section XI has been performed and is provided in. Note that ASME Code Case N-504-2 has been conditionally approved by the NRC in RG 1.147 with the condition that the provisions of ASME Section XI, Appendix Q be met when using the Case.

This proposed alternative provides an acceptable methodology for preventing potential failures due to PWSCC based on the use of filler metals that are resistant to PWSCC (e.g., Alloy 52M),

procedures that create compressive residual stress profiles in the original weld, and post-overlay preservice and inservice inspection requirements that ensure structural integrity for the life of the plant. The proposed weld overlays will also meet the applicable stress limits from ASME Section III. Crack growth evaluations for PWSCC and fatigue of any conservatively postulated flaws will demonstrate that structural integrity will be maintained.

As stated above, preemptive weld overlays will be installed using Alloy 52M filler metal in accordance with Attachment 2. However, Alloy 52M weld metal has demonstrated sensitivity to certain impurities, such as sulfur, when deposited on to austenitic stainless steel base materials.

Therefore, a buffer (transitional) layer of authentic stainless steel filler metal will be applied across the austenitic stainless steel base material. The austenitic stainless steel buffer layer will not be included in the structural weld overlay thickness as defined in Attachment 2.

1.

Weld Overlay Design and Verification The fundamental design basis for full structural weld overlays is to maintain the original design margins with no credit taken for the underlying PWSCC-susceptible weldments.

The assumed design basis flaw for the purpose of structural sizing the weld overlays is 3600 and 100% through the original wall thickness of the DMWs. Regarding the crack growth analysis for the preemptive full structural weld overlay, a flaw originating from the inside diameter with a depth of 75% and a circumference of 3600 will be assumed.- A 75% through-wall flaw is the largest flaw that could remain undetected. A preservice volumetric examination will be performed after application of the weld overlay using an ASME Section Xl, Appendix VIII (as implemented through PDI) examination procedure..

This examination will verify that there is no cracking in the upper 25% of the original weld and base material. The preservice examination will also demonstrate that the assumption of a 75% through-wall crack is conservative. However, if any crack-like flaws are identified in the upper 25% of the original weld or base material by the preservice examination, then the as-found flaw (postulated 75% through-wall flaw plus the portion of the flaw in the upper 25%) will be used in the crack growth analysis.

to 1 CAN 100702 Page 5 of 14 The specific analyses and verifications to be performed are summarized as follows:

Nozzle-specific stress analyses will be performed to establish a residual stress profile in each nozzle. Severe internal diameter weld repairs will be assumed in these analyses that effectively bound any actual weld repairs that may have occurred in the nozzles. The analyses will then simulate application of the weld overlays to determine the final residual stress profiles. Post-weld' overlay residual stresses at normal operating conditions will be shown to result in beneficial compressive stresses on the inside surface of the components, assuring that further crack initiation due to PWSCC is highly unlikely.

Fracture mechanics analyses will also be performed to predict crack growth for postulated flaws. Crack growth due to PWSCC and fatigue will be analyzed for the original DMW. The crack growth analyses will consider all design loads and transients, plus the post-weld overlay and through-wall residual stress distributions.

The analyses will demonstrate that the postulated cracks will not grow beyond the design basis for the weld overlays.

0 The analyses will demonstrate that applying the weld overlays does not impact the conclusions of the existing nozzle stress reports. The ASME Code,Section III stress and fatigue criteria will be met for regions of the overlays remote from assumed cracks.

Shrinkage will be measured during the overlay application. Shrinkage stresses at other locations in the piping systems arising from the weld overlays will be demonstrated not to have an adverse effect on the systems. Clearances of affected support and restraints will be checked after the overlay repair and will be reset within the design ranges as required.

The total added weight on the piping systems due to the overlays will be evaluated for potential impact on piping system stresses and dynamic characteristics.

The as-built dimensions of the weld overlays will be measured and evaluated to demonstrate that they meet or exceed the minimum design dimensions of the overlays.

2.

Suitability of Proposed Ambient Temperature Temperbead Technique An ambient temperature temperbead welding technique will be used when welding on the ferritic base materials of the nozzles in lieu of the post-weld heat treatment requirements of ASME Section II1. Research by the Electric Power Research Institute (EPRI) and other organizations on the use of an ambient temperature temperbead process using the machine gas tungsten arc welding (GTAW) process is documented in EPRI Report GC-1 11050 (Reference 7). According to the EPRI report, repair welds performed with an ambient temperature temperbead procedure utilizing the machine GTAW welding process exhibit mechanical properties equivalent to or better than those of the surrounding base material. Laboratory testing, analysis, successful procedure qualifications, and successful repairs have all demonstrated the effectiveness of this process.

to 1CAN100702 Page 6 of 14

a.

Suitability of Ambient Temperature Temperbead Welding The effects of the ambient temperature temperbead welding process of on mechanical properties of welds, hydrogen cracking, and cold restraint cracking are addressed in the following paragraphs:

• Mechanical Properties The principal reasons to preheat a component prior to repair welding is to minimize the potential for cold cracking. The two cold cracking mechanisms are hydrogen cracking and restraint cracking. Boti of these mechanisms occur at ambient temperature. Preheating slows down the cooling rate resulting in a ductile, less brittle microstructure thereby lowering susceptibility to cold cracking.

Preheat also increases the diffusion rate of monatomic hydrogen that may have been trapped in the weld during solidification.

As an alternative to preheat, the ambient temperature temperbead welding process utilizes the tempering action of the welding procedure to produce tough and ductile microstructures. Because precision bead placement and heat input control are utilized in the machine GTAW process, effective tempering of weld heat affected zones (HAZ) is possible without applying preheat. According to Section 2-1 of EPRI Report GC-1 11050, "the temperbead process is carefully designed and controlled such that successive weld beads supply the appropriate quantity of heat to the untempered HAZ such that the desired degree of carbide precipitation (tempering) is achieved. The resulting microstructure is very tough and ductile."

The IWA-4630 temperbead process includes a post-weld soak requirement.

Performed at 300 OF for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> (P-No. 1 base materials), this post-weld soak assists diffusion of any remaining hydrogen from the repair weld. As such, the post-weld soak is a hydrogen bake-out and not a post-weld heat treatment as defined by the ASME Code. At 300 OF, the post-weld soak does not stress relieve, temper, or alter the mechanical properties of the weldment in any manner.

The alternative described in Attachment 3 establishes detailed welding procedure qualification requirements for base materials, filler metals, restraint, impact properties, and other procedure variables. The qualification requirements contained in Attachment 3 provide assurance that the mechanical properties of repair welds will be equivalent to or superior to those of the surrounding base material.

Hydrogen Cracking Hydrogen cracking is a form of cold cracking. It is produced, by the action of internal tensile stresses acting on low toughness HAZs. The internal stresses are produced from localized build-ups of monatomic hydrogen. Monatomic hydrogen forms when moisture or hydrocarbons interact with the welding arc and molten weld pool. The monatomic hydrogen can be entrapped during weld to 1CAN100702 Page 7 of 14 solidification and tends to migrate to transformation boundaries or other microstructure defect locations. As concentrations build, the monatomic hydrogen will recombine to form molecular hydrogen, thus generating localized internal stresses at these internal defect locations. If these stresses exceed the fracture toughness of the material, hydrogen-induced cracking will occur. This form-of cracking requires the presence of hydrogen and low toughness materials.

It is manifested by intergranular cracking of susceptible materials and normally occurs within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> of welding.

Subsection IWA-4600 establishes elevated preheat and post-weld soak requirements. The elevated preheat temperature of 300 OF increases the diffusion rate of hydrogen from the weld. The post-weld soak at 300 °F was also established to bake-out or facilitate diffusion of any remaining hydrogen from the weldment. However, while hydrogen cracking is a concern for shielded metal arc welding (SMAW), which uses flux covered electrodes, the potential for hydrogen cracking is significantly reduced when using the machine GTAW welding process.

The machine GTAW welding process is inherently free of hydrogen. Unlike the filler metal used in the SMAW process, GTAW welding filler metals do not rely on flux coverings, which may be susceptible to moisture absorption from the environment. Conversely, the GTAW process utilizes dry inert shielding gases that cover the molten weld pool from oxidizing atmospheres. Any moisture on the surface of the component being welded will be vaporized ahead of the welding torch. The vapor is prevented from being mixed with the molten weld pool by the inert shielding gas that blows the vapor away before it can be mixed.

Furthermore, modern filler metal manufacturers produce wires having very low residual hydrogen. This is important because filler metals and base materials are the most realistic sources of hydrogen for automatic or machine GTAW temperbead welding. Therefore, the potential for hydrogen-induced cracking is greatly reduced by using the machine GTAW process.

In the unlikely event that hydrogen.cracking occurs, nondestructive examination (NDE) of the weldment will be not be performed until at least 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after completing the third layer of the weld overlay, thereby providing assurance that the cracking would be identified. See paragraphs 3.e and 3.f below for additional information.

Cold Restraint Cracking Cold cracking generally occurs during cooling at temperatures approaching ambient temperature. As stresses build under a high degree of restraint, cracking may occur at defect locations. Brittle microstructures with low ductility are subject to cold restraint cracking. However, the ambient temperature temperbead process is designed to provide a sufficient heat inventory so as to produce the desired tempering for high toughness. Because the machine GTAW temperbead process provides precision bead placement and control of heat, the toughness and ductility of the HAZ will typically be superior to the base material.

Therefore, the resulting structure will be appropriately tempered to exhibit toughness sufficient to resist cold cracking.

to 1 CAN 100702 Page 8 of 14

b.

Exceptions to ASME Code Case N-638-1 Conditions The ambient temperature temperbead technique of Code Case N-638-1 was conditionally approved by the NRC in RG 1.147. The proposed ambient temperature temperbead welding technique of Attachment 3 is identical to Code Case N-638-1 with the following exceptions:

Code Case N-638-1, paragraph 1.0(a) limits the maximum area of an individual weld to 100 square inches. The proposed alternative limits the surface area to 500 square inches. The technical basis for this change is provided in.

Code Case N-638-1, paragraph 1.0(a) states that "the depth of the weld shall not be greater than one-half of the ferritic base metal thickness." Because the proposed alternative applies to deposition of weld overlays for which there are no weld or base material excavations, this limitation does not apply and is not included in Attachment 3.

" When welding is to be performed in a pressurized environment (e.g., an enclosed environment that is pressurized to prevent leakage so that welding can be performed), Code Case N-638-1, paragraph 2.1(b) requires that the pressurized environment be duplicated in the procedure qualification test assembly. Because this condition does not exist when applying weld overlays, this requirement is not included in Attachment 3.

When welding is performed inthe core beltline region of the reactor pressure vessel, Code Case N-638-1, paragraph 2.1(c) requires that the effects of irradiation on the properties of the materials be considered. Because weld overlays will not be applied to the core beltline region of the reactor pressure vessel, this requirement is not included in Attachment 3.

Code Case N-638-1, paragraph 2.1(h) requires the performance of Charpy V-notch testing of the ferritic weld metal of the procedure qualification test coupon. Because austenitic weld metal (i.e., Inconel Alloy 52 "Modified") will be used to fabricate the proposed weld overlays, this requirement does not apply and is not included in Attachment 3.

Code Case-N-638-1, paragraph 2.10) specifies acceptance criteria for Charpy V-notch tests of the HAZ. According to paragraph 2.1(j), the "average values of the three HAZ impact tests shall be equal to or greater than the average values of the three unaffected base metal tests." Although not explicitly stated, the average values referred to in paragraph 2.10) are the average lateral expansion values of the HAZ and base material specimens. Because this is the case, the acceptance criteria for Charpy V-notch testing of the HAZ is also based on average lateral expansion values in the proposed alternative. The technical basis for this change is provided in Attachment 5.

to 1 CAN100702 Page 9 of 14 0

Code Case N-638-1, paragraph 3.0(c) requires the deposition and removal of at least one weld reinforcement layer for "similar materials" (i.e., ferritic materials).

This requirement is only applicable when welding is performed using ferritic filler weld metal. When temperbead welding is performed with ferritic filler metal, each ferritic weld layer must be tempered by the heat supplied from a subsequent weld layer. Because the last layer of a weld or weld repair would be untempered without the deposition of one additional weld layer, paragraph 3.0(c) requires the deposition and removal of a reinforcement layer to provide the required tempering. Since only austenitic filler metal (i.e.,

Alloy 52M) will be used-to fabricate the proposed weld overlays, depositing and removing a weld reinforcement layer is not required. Therefore, this requirement is not included into Attachment 3.

Because Code Case N-638-1, paragraph 3.0 does not specifically address monitoring or verification of welding interpass temperatures, interpass temperature controls have been specified in Attachment 3. The proposed interpass temperature controls are based on field experience with depositing weld overlays. Interpass temperature beyond the third layer has no impact on the metallurgical properties of the low alloy steel HAZ.

0 As an alternative to the examination requirements of Section 4.0 of Code Case N-638-1, the weld overlay will be examined in accordance with the examination and inspection requirements of Attachment 2, Section 3.0. The suitability of the proposed examinations is described in paragraph 3, below.

3.

Suitability of Proposed NDE The length, surface finish, and flatness requirements will be specified in the weld overlay design to provide for inspection of the examination volumes shown in Attachment 2, Figures 1 and 2. Furthermore, the examinations and inspections specified in this proposed alternative will provide adequate assurance of structural integrity for the following reasons:

a.

Weld overlays have been used for repair and mitigation of cracking in BWRs since the early 1980s. In Generic Letter (GL) 88-01, NRC Position on Intergranular Stress Corrosion Cracking (IGSCC) in BWR Austenitic Stainless Steel Piping, the NRC approved the use of ASME Section XI acceptance standards for determining the acceptability of installed weld overlays.

b.

The ultrasonic examinations performed in accordance with the proposed alternative are in accordance with ASME Section Xl, Appendix VIII, Supplement 11 as implemented through the PDI. These examinations are considered more sensitive for detecting fabrication and service-induced flaws than the ASME Section III radiographic or ultrasonic examination methods. Furthermore, construction-type flaws have been included in the PDI qualification sample sets for evaluating procedures and personnel.

to 1 CAN 100702 Page 11 of 14 austenitic materials. If it occurs in the ferritic base material below the weld overlay, it will be detected by the ultrasonic examination which will interrogate the entire weld overlay including the interface and HAZ beneath the weld overlay. If it occurs in the ferritic base material immediately adjacent to the weld overlay, it will be detected by the liquid penetrant examination which is performed at least 1/2 inch on each side of the weld overlay. Finally, when ambient temperature temperbead welding is performed over ferritic materials, the liquid penetrant and ultrasonic examinations will not be performed until at least 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after completing of the third layer of the weld overlay. Technical justification for initiating the 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> hold after completing the third layer is provided in paragraph 3.f below.

f.

Based on Code Case N-740, the 48-hour hold for performing NDE starts after the weld overlay cools to ambient temperature when performing ambient temperature temperbead welding. This 48-hour hold is'specified to allow sufficient time for hydrogen cracking to occur (if it is to occur) in the HAZ of ferritic materials prior to performing final NDE. However, based on extensive research and industry experience, EPRI has provided a technical basis for starting the 48-hour hold after completing the third temperbead weld layer rather than waiting for the weld overlay to cool to ambient temperature (weld layers beyond the third layer are not designed to provide tempering to the ferritic HAZ when performing ambient temperature temperbead welding). EPRI has documented their technical basis in technical report 1013558, Temper Bead Welding Applications - 48 Hour Hold Requirements for Ambient Temperature Temper Bead Welding (Reference 9). Although the technical data provided by EPRI in their report is based on the testing performed on SA-508, Class 2 low alloy steels and other P-Number 3, Group 3 materials, the conclusions are bounding and applicable to P-Number 1 carbon steels which have a lower carbon equivalent and lower hardenability. This point is important because the "A" hot leg piping nozzle is manufactured from carbon steel (A-105, Grade II).

After evaluating the issues relevant to hydrogen cracking such as microstructure of susceptible materials, availability of hydrogen, applied stresses, temperature, and diffusivity and solubility of hydrogen in steels, EPRI concluded the following on page 5-2 of the report: "There appears to be no technical basis for waiting 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after cooling to ambient temperature before beginning the NDE of the completed weld. There should be no hydrogen present, and even if it were present, the temper bead welded component should be very tolerant of the moisture." Page 5-2 of the report also notes that over 20 weld overlays and 100 repairs have been performed using temper bead techniques on low alloy steel components over the last 20 years.

During this time, there has never been an indication of hydrogen cracking by the nondestructive examination performed after the 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> hold or by subsequent inservice inspection.

In addition, the ASME Section XI Committee approved Revision 4 to Code Case N-638 (i.e., N-638-4) in October 2006 to allow the 48-hour hold to begin after completing the third weld layer when using austenitic filler metals. Paragraph 4(a)(2) of the code case states in part: "When austenitic materials are used, the weld shall be nondestructively examined after the three tempering layers (i.e., layers 1, 2, and

3) have been in place for at least 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />." The ASME Section Xl technical basis for this change is documented in the white paper contained in ASME C&S Connect for Code Case N-638-4. The ASME white paper points out that introducing to 1CAN100702 Page 12 of 14 hydrogen to the ferritic HAZ is limited to the first weld layer since this is the only weld layer that makes contact with the ferritic base material. While the potential for introducing hydrogen to the ferritic HAZ is negligible during subsequent weld layers, these layers provide a heat source that accelerates the dissipation of hydrogen from, the ferritic HAZ in non-water backed applications. Furthermore, the solubility of hydrogen in austenitic materials such as Alloy 52M is much higher than that of ferritic materials, while the diffusivity of hydrogen in austenitic materials is lower than that of ferritic materials. As a result, hydrogen in the ferritic HAZ tends to diffuse into the austenitic weld metal which has a much higher solubility for hydrogen. This diffusion process is enhanced by. heat supplied in subsequent weld layers. Like the EPRI report, the ASME white paper concludes that there is sufficient delay time to facilitate detecting potential hydrogen cracking when NDE is performed 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after completing the third weld layer.

g.

The successive examination requirements of Attachment 2, paragraph 3.0(c) ensure that cracks identified by inservice inspections are appropriately monitored.

According to paragraph 3.0(c) of Attachment 2, the weld overlay "shall be reexamined during the first or second refueling outage following discovery of the growth or new cracking." If additional crack growth or a new crack is discovered during a successive examination, then the successive examination of the weld overlay would be re-performed within the next two refueling outages. However, if the successive examination of the weld overlay reveals no additional indication of crack growth or new cracking, the weld overlay shall be placed into a population to be examined on a sample basis. Twenty-five percent (25%) of this population shall be examined once every ten (10) years. This successive examination schedule is identical to that specified in paragraph Q-4300 of ASME Section Xl, Appendix Q which has been imposed as a condition to using Code Case N-504-2 by the NRC in RG 1.147.

h.

The examination and inspection requirements in Attachment 2, Section 3.0 are equivalent to or more conservative than the examination and inspection requirements of Appendix Q of ASME Section XI as demonstrated in the comparison provided in Attachment 4 of this request.

4.

NRC Submittals As listed in Enclosure 2, Entergy will submit the following information to the NRC within fourteen (14) days from completing the final ultrasonic examinations of the completed weld overlays:

Weld overlay examination results including a listing of indications detected1 1 The recording criteria of the ultrasonic examination procedure to be used for the weld overlay examination requires that all indications, regardless of amplitude, be investigated to the extent necessary to provide accurate characterization, identity, and location. Additionally, the procedure requires that all indications, regardless of amplitude, that cannot be clearly attributed to the geometry of the overlay configuration be considered flaw indications.

to 1CAN100702 Page 13 of 14.

Disposition of indications using the standards of ASME Section XI, Subsection IWB-3514-2 and/or IWB-3514-3 criteria and, if possible, the type and nature of the indications 2

A discussion of any repairs to the weld overlay material and/or base metal and the reason for the repairs.

Entergy will also submit to the NRC a stress analysis summary demonstrating that the hot leg piping nozzle will perform its intended design function after weld overlay installation. The stress analysis report will include results showing that the requirements of NB-3200 and NB-3600 of the ASME Code,Section III are satisfied. The stress analysis will also include results showing that the requirements of Subsection IWB-3000 of the ASME Code, Section Xl, are satisfied. The results will show that the postulated crack including its growth in the nozzles will not adversely affect the integrity of the overlaid welds. This information will be submitted to the NRC prior to entry into Mode 4 following the ANO-1 refueling outage 1 R21.

B.

Proposed Alternative to ASME Section XI Appendix VIII, Supplement 11 Appendix VIII, Supplement 11 of the 2001 Edition of ASME Section XI specifies requirements for performance demonstration of ultrasonic examination procedures, equipment, and personnel used to detect and size flaws in full structural overlays of wrought austenitic piping welds.

Entergy modifies the Appendix VIII, Supplement 11 qualification requirements by the proposed alternatives in the Performance Demonstration Initiative (PDI) Program as indicated in of this request because the industry cannot meet the requirements of Appendix VIII, Supplement 11. Therefore, the PDI initiatives to ASME Section XI Appendix VIII, Supplement 11 as described in Attachment 6 will be used for qualification of ultrasonic examinations used to detect and size flaws in the preemptive full structural weld overlays of this request.

VI.

CONCLUSION 10 CFR 50.55a(a)(3)(i) states:

"Proposed alternatives to the requirements of (c), (d), (e), (f), (g), and (h) of this section or portions thereof may be used when authorized by the Director of the Office of Nuclear Reactor Regulation. The applicant shall demonstrate that:

(i) The proposed alternatives would provide an acceptable level of quality and safety, or (ii) Compliance with the specified requirements of this section would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety."

2 The ultrasonic examination procedure requires that all suspected flaw indications are to be plotted on a cross-sectional drawing of the weld and that the plots should accurately identify the specific origin of the reflector.

to 1CAN100702 Page 14 of 14 Entergy believes that the proposed alternatives of this request provide an acceptable level of quality and safety. The proposed preemptive weld overlay will be installed using Nickel Alloy 52M filler metal that is resistant to PWSCC. While this is the case, the weld overlay will also create compressive residual stresses along the inside diameter of the original 'weld, which prevents the initiation of new PWSCC. Finally, preservice and inservice inspection of the weld overlay will be performed to ensure structural integrity is maintained. Therefore, Entergy requests that the NRC staff authorize the proposed alternative in accordance with 10 CFR 50.55a(a)(3)(i).

VII DURATION OF PROPOSED ALTERNATIVE The proposed alternative is applicable to the fourth (4 th) 10-Year ISI interval for ANO-1.

1CAN100702 Dissimilar Metal Weld Details and Figures to 1 CAN 100702 Page 1 of 2 DISSIMILAR METAL WELD DETAILS Hot Leg "A" to A-105, Grade Ill DMW 82/1822, A-403, WP316 3 12" NPS Decay Heat Piping w/SST Clad ID 17-017 1

Notes:

1.

2.

3.

Nozzle material is carbon steel (P-No. 1).

DMW includes butter and weld.

Elbow material is stainless steel (P-No. 8).

to 1CAN 100702 Page 2 of 2 FIGURE 1 I

I I

1CAN100702 Proposed Alternative for Preemptive Full Structural Weld Overlays to 1 CAN100702.

Page 1 of 6 PROPOSED ALTERNATIVE FOR PREEMPTIVEFULL STRUCTURAL WELD OVERLAYS 1.0 GENERAL REQUIREMENTS (a) Weld overlays may be applied to the 82/182 dissimilar metal welds joining the materials listed below.

Carbon steel (P-No. 1) to stainless steel (P-No. 8) materials (b)

Weld overlay filler metal shall be austenitic Nickel Alloy 52M (ERNiCrFe-7A) filler metal having a chromium content of at least 28%. The weld overlay is applied 3600 around the circumference of the item, and shall be deposited using a Welding Procedure Specification (WPS) for groove welding, qualified in accordance with the Construction Code and Owner's Requirements, and identified in the Repair/Replacement Plan. As an alternative to the post-weld heat treatment requirements of the Construction Code and Owner's requirements, the provisions for "Ambient Temperature Temperbead Welding" may be used on the ferritic nozzle as described in Attachment 3.

(c) Prior to~deposition of the weld overlay, the surface to be repairedshall be examined by the liquid penetrant method. Indications larger than 1/16 inch (1.5 mm) shall be removed, reduced in size, or corrected in accordance with the following requirements.

(1) One or more layers of weld metal-shall be applied to seal unacceptable indications in the area to be repaired with or without excavation. The thickness of these layers shall not be used in meeting weld reinforcement design thickness requirements.

Peening the unacceptable indication prior to welding is permitted.

(2) If correcting indications identified in 1.0(c) is required, the area where the weld overlay is to be deposited, including any local repairs or initial weld overlay layer, shall be examined by the liquid penetrant method. The area shall contain no indications greater than 1/16 inch (1.5 mm) prior to applying the structural layers of the weld overlay.

(d) Weld overlay'depOsits shall meet the following requirements:

The austenitic nickel alloy weld overlay shall consist of at least two weld layers deposited with a filler material such as identified in 1.0(b) above. The first layer of weld metal deposited may not be credited toward the required thickness. Alternatively, a diluted layer may be credited toward the required thickness, provided the portion of the layer over the austenitic base material, austenitic weld, and the associated dilution zone from an adjacent ferritic base material contains at least 24% chromium. The chromium content of the deposited weld metal may be determined by chemical analysis of the production weld or from a representative coupon taken from a mockup prepared in accordance with the WPS for the production weld.

(6) A new weld overlay shall not be installed on top of an existing weld overlay that has been in service.

to 1 CAN 100702 Page 2 of 6 2.0 CRACK GROWTH CONSIDERATIONS AND DESIGN (a) Crack Growth Because the full structural weld overlays are being installed preemptively, a flaw With a depth of 75% and a circumference of 360° will be assumed. The size of the assumed flaws shall be projected to the end of the design life of the overlay. Crack growth, including both stress corrosion and fatigue crack growth, shall be evaluated in the materials in accordance with IWB-3640. If the flaw is at or near the boundary of two different materials, evaluation of flaw growth in both materials will be performed.

(b) Structural Design The design of the weld overlay shall be analyzed and shown to satisfy the following, using the assumptions and flaw characterization restrictions in 2.0(a):

(1) The axial length and end slope of the weld overlay shall cover the weld and the heat affected zones (HAZs) on each side of the weld, and shall provide for load redistribution from the item into the weld overlay and back into the item without violating applicable stress limits of NB-3200. Any laminar flaws in the weld overlay shall be evaluated in the analysis to ensure that load redistribution complies with the above. These requirements will usually be satisfied if the weld overlay full thickness length extends axially beyond the projected flaw by at least 0.754Rt, where "R" is the outer radius of the item and "t" is the nominal wall thickness of the item.

(2) Unless specifically analyzed in accordance with 2.0(b)(1) above, the end transition slope of the overlay shall not exceed 450. A slope of not more than 1:3 is recommended.

(3) Because the full structural weld overlays are being installed preemptively, flaws shall be assumed to be 100% through the original wall thickness for the entire circumference.

(4) The overlay design thickness of items meeting 2.0(b)(3) above shall be based on the measured diameter using only the weld overlay thickness conforming to the deposit analysis requirements of 1.0(d) above. The combined wall thickness at the weld overlay, any planar flaws in the.weld overlay, the flaw size assumptions of 2.0(b)(3) above, and the effects of any discontinuity (e.g., another weld overlay or reinforcement for a branch connection) within a distance of 2.54/Rt from the toes of the weld overlay, shall be evaluated and shall meet the requirements of IWB-3640.

(5) The effects of any changes in applied loads, as a result of weld shrinkage from the entire overlay, on other items in the piping system (e.g., support loads and

.clearances, nozzle loads, changes in system flexibility and weight due to the weld overlay) shall be evaluated. Existing flaws previously accepted by analytical evaluation shall be evaluated in accordance with IWB-3640.

Note: Although planar flaws are considered in the IWB-3640 evaluation of the combined wall thickness in paragraph 2.0(b)(4), these planar flaws must meet the acceptance standards of IWB-3500 as required by Attachment 2, paragraphs 3.0(a) and (b) of ANO1-R&R-011.

to 1CAN100702 Page 3 of 6

\\

3.0 EXAMINATION AND INSPECTION

-In lieu of all other examination requirements, the examination requirements proposed herein shall be met. Nondestructive examination (NDE) methods shall be in accordance with IWA-2200, except as specified herein. NDE personnel shall be qualified in accordance with IWA-2300.

Ultrasonic examination procedures and personnel shall be qualified in accordance with Appendix VIII of ASME Section XI.

(a) Acceptance Examination (1) The weld overlay shall have a surface finish of 250 micro-inch (6.3 micrometers)

RMS or better and a flatness that is sufficient to allow for adequate examination in accordance with procedures qualified per Appendix VIII. The weld overlay shall be examined to verify acceptable configuration.

(2) The weld overlay and the adjacent base material for at least 11/2 inch (13 mm) from each side of the weld shall be examined using the liquid penetrant method. The weld overlay shall satisfy the surface examination acceptance criteria for welds of the Construction Code or ASME Section III, NB-5300. The adjacent base metal shall satisfy the surface examination acceptance criteria for base material of the Construction Code or ASME Section III, NB-2500. If ambient temperature temperbead welding is used, liquid penetrant examination shall be conducted at least 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after completing the third layer of the weld overlay.

(3) The examination volume A-B-C-D in Figure 1 (below) shall be ultrasonically examined to assure adequate fusion (i.e., adequate bond) with the base metal and to detect welding flaws, such as inter-bead lack of fusion, inclusions, or cracks. The interface C-D shown between the overlay and the weld includes the bond and the HAZ from the overlay. If ambient temperature temperbead welding is used, the ultrasonic examination shall be conducted at least 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after completing the third layer of the weld overlay. Planar flaws shall meet the preservice examination standards of Table IWB-3514-2. In applying the acceptance standards, wall thickness "tw" shall be the thickness of the weld overlay. Laminar flaws shall meet the following:

(i)

Laminar flaws shall meet the acceptance standards of Table IWB-3514-3 with the additional limitation that the total laminar flaw shall not exceed 10% of the weld surface area and that no linear dimension of the laminar flaw area exceeds 3.0 inches (76 mm).

(ii) The reduction in coverage of the examination volume in Figure 1 due to laminar flaws shall be less than 10%. The dimensions of the un-inspectable volume are dependent on the coverage achieved with the angle beam examination of the overlay.

(iii)

Any un-inspectable volume in the weld overlay shall be assumed to contain the largest radial planar flaw that could exist within that volume. This assumed flaw shall meet the inservice examination standards of Table IWB-3514-2.

Alternately, the assumed flaw shall be evaluated and shall meet the requirements of IWB-3640. Both axial and circumferential planar flaws shall be assumed.

to 1 CAN 100702 Page 4 of 6 (4) If a weld overlay does not meet the acceptance standards specified in 3.0(a)(2) and (3) above, the weld overlay shall be corrected by a repair/replacement activity in accordance with IWA-4000.

(5) After completing welding activities, affected restraints, supports, and snubbers shall be VT-3 visually examined to verify that design tolerances are met.

(b) Preservice Inspection (1) The examination volume A-B-C-D in Figure 2 (below) shall be ultrasonically examined. The angle beam shall be directed perpendicular and parallel to the piping axis, with scanning performed in four directions to locate and size any cracks that might have propagated into the upper 25% of the base material or into the weld overlay. If ambient temperature temperbead welding is used, the ultrasonic examination shall be conducted at least 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after completing the third layer of the weld overlay.

(2) The preservice examination acceptance standards of Table IWB-3514-2 shall be met for the weld overlay. In applying the acceptance standards, wall thickness, t',

shall be the thickness of the weld overlay. Cracks in the outer 25% of the base metal shall meet the design analysis requirements of 2.0 above.

(c) Inservice Inspection (1) The weld overlay examination volume A-B-C-D in Figure 2 shall be added to the inspection plan and shall be ultrasonically examined during the first or second refueling outage following application.

(2) The weld overlay examination volume in Figure 2'shall be ultrasonically examined to determine if any new or existing cracks have propagated into the upper 25% of the base material or into the overlay. The angle beam shall be directed perpendicular and parallel to the piping axis, with scanning performed in four directions.

(3) The acceptance standards for the ultrasonic examination of the weld overlay are specified in Table IWB-3514-2.

However, if the weld overlay fails to meet the acceptance standards of Table IWB-3514-2, it can be accepted based on an analytical evaluation meeting the requirements and acceptance criteria of IWB-3600. However, flaws identified as primary water stress corrosion cracking (PWSCC) cannot be accepted by an IWB-3600 analytical evaluation. Cracks in the

• outer 25% of the base metal shall meet the design analysis requirements of 2.0 above.

(4) Weld overlay examination volumes that show no indication of crack growth or new cracking shall be placed into a population to be examined on a sample basis.

Twenty-five percent of this population shall be examined once every ten years.

to 1CAN100702" Page 5 of 6 (5) If inservice examinations reveal crack growth, or new cracking, meeting the acceptance standards, the weld overlay examination volume shall be reexamined during the first or second refueling outage following discovery of the growth or new cracking. Weld overlay. examination volumes that show no additional indication of crack growth or new cracking shall be placed into a population to be examined on a sample basis. Twenty-five percent (25%) of this population shall be examined once every ten years.

(6) For weld overlay examination volumes that fail to meet the acceptance criteria as described in 3.0(c)(3) above, the weld overlay shall be removed, including the original defective weld, and the item shall be corrected by a repair/replacement activity in accordance with IWA-4000.

(d) Additional Examinations If inservice examinations reveal an unacceptable indication, crack growth into the weld overlay design thickness, or axial crack growth beyond the specified examination volume, additional weld overlay examination volumes, equal to the number scheduled for the current inspection period, shall be examined prior to return to service. If additional unacceptable indications are found in the second sample, 50% of the total population of weld overlay examination volumes shall be examined prior to operation. If additional unacceptable indications are found, the entire remaining population of weld overlay examination volumes shall be examined prior to return to service.

4.0 PRESSURE TESTING A system leakage test shall be performed in accordance with IWA-5000.

5.0 DOCUMENTATION Use of this alternative shall be documented on Form NIS-2. Alternatively, it may be documented on Form NIS-2A as described in Code Case N-532-4 based on appropriate NRC approval.

to 1 CAN 100702 Page 6 of 6 FIGURE 1 ACCEPTANCE EXAMINATION VOLUME A

B Examination Volume A-B-C-D FIGURE 2 PRESERVICE AND INSERVICE EXAMINATION VOLUME Examination Volume A-B-C-D NOTE For axial or circumferential flaws, the axial extent of the examination volume shall extend at least 1/2 inch (13 mm) beyond the as-found flaw and at least 1/2 inch (13 mm) beyond the toes of the original weld, including weld end butter, where applied.

1CAN100702 Proposed Ambient Temperature Temperbead Technique to 1 CAN 100702 Page 1 of 4 PROPOSED AMBIENT TEMPERATURE TEMPERBEAD TECHNIQUE 1.0 GENERAL REQUIREMENTS (a) This appendix applies to dissimilar austenitic filler metal welds joining P-No. 8 material to P-No. 1 material.

(b) The maximum area of an individual weld overlay based on the finished surface over the ferritic base material shall be 500 square inches.

(c) Repair/replacement activities on a dissimilar-metal weld in accordance with this attachment are limited to those along the fusion line of a nonferritic weld to ferritic base material on which 1/8 inch, or less of nonferritic weld deposit exists above the original fusion line.

(d) If a defect penetrates into the ferritic base material, repair of the base material, using a nonferritic weld filler material, may be performed in accordance with this attachment, provided the depth of repair in the base material does not exceed 3/8 inch.

(e) Prior to welding the area to be welded and a band around the area of at least 11/2 times the component thickness or 5 inches, whichever is less, shall be at least 50 OF (10 °C).

(f)

Welding materials shall meet the Owner's Requirements and the Construction Code and Cases specified in the Repair/Replacement Plan. Welding materials shall be controlled so that they are identified as acceptable until consumed.

(g) Peening may be used, except on the initial and final layers.

2.0 WELDING QUALIFICATIONS 2.1 Procedure Qualification (a) The base materials for the welding procedure qualification shall be of the same P-Number and Group Number, as the materials to be welded. The materials shall be post-weld heat treated to at least the time and temperature that was applied to the materials being welded.

(b) The root width and included angle of the cavity in the test assembly shall be no greater than the minimum specified for the repair.

(c) The maximum interpass temperature for the first three layers of the test assembly shall be 150 OF (66 °C).

• (d) The test assembly cavity depth shall be at least 1 inch (25 mm). The test assembly thickness shall be at least twice the test assembly cavity depth. The test assembly shall be large enough to permit removing the required test specimens. The test assembly dimensions surrounding the cavity shall be at least the test assembly thickness and at least 6 inches (150 mm). The qualification test plate shall be prepared in accordance with Figure 1-1.

to 1 CAN 100702 Page 2 of 4 (e) Ferritic base material for the procedure qualification test shall meet the impact test requirements of the Construction Code and Owner's Requirements. If such requirements are not in the Construction Code and Owner's Requirements, the impact properties shall be determined by Charpy V-notch impact tests of the procedure qualification base material at or below the lowest service temperature of the item to be repaired. The location and orientation of the test specimens shall be similar to those required in (f) below, but shall be in the base metal.

(f)

Charpy V-notch tests of the ferritic heat-affected zone (HAZ) shall be performed at the same temperature as the base metal test of (e) above. Number, location, and orientation of test specimens shall be as follows:

(1) The specimens shall be removed from a location as near as practical to a depth of one-half the thickness of the deposited weld metal. The coupons for HAZ impact specimens shall be taken transverse to the axis of the weld and etched to define the HAZ. The notch of the Charpy V-notch specimen shall be cut approximately normal to the material surface in such a manner as to include as much HAZ as possible in the resulting fracture. Where the material thickness permits, the axis of a specimen shall be inclined to allow the root of the notch to be aligned parallel to the fusion line.

(2) If the test material is in the form of a plate or a forging, the axis of the weld shall be oriented parallel to the principal direction of rolling or forging.

(3) The Charpy V-notch test shall be performed in accordance with SA-370.

Specimens shall be in accordance with SA-370, Figure 11, Type A. The test shall consist of a set of three full-size 10 mm X 10 mm specimens. The lateral expansion, percent shear, absorbed energy, test temperature, orientation and location of all test specimens shall be reported in the Procedure Qualification Record.

(g) The average lateral expansion value of the three HAZ Charpy V-notch specimens shall be equal to or greater than the average lateral expansion value of the three unaffected base metal specimens.

2.2 Performance Qualification Welding operators shall be qualified in accordance with ASME Section IX.

3.0 WELDING PROCEDURE REQUIREMENTS The welding procedure shall include the following requirements.

(a) The weld metal shall be deposited by the automatic or machine gas tungsten arc welding (GTAW) process.

(b) Dissimilar metal welds shall be made using F-No. 43 weld metal (QW-432) for P-No. 8 to P-No. 1 weld joints.

to 1CAN100702 Page 3 of 4 (c) The area to be welded shall be buttered with a deposit of at least three layers to achieve at least 1/8 inch (3mm) overlay thickness with the heat input for each layer controlled to within +/-10% of that used in the procedure qualification test. Particular care shall be taken in the placement of the weld layers of the austenitic overlay filler material at the toe of the overlay to ensure that the HAZ and ferritic base metal are tempered.

Subsequent layers shall be deposited with a heat input not exceeding that used for layers beyond the third layer in the procedure qualification, (d) The maximum interpass temperature for field applications shall be 350 OF (180 0C) for all weld layers regardless of the interpass temperature used during qualification.

(e) The preheat and interpass temperatures will be measured using a contact pyrometer. In the first three layers, the interpass temperature will be measured every three to five passes. After the first three layers, interpass temperature measurements will be taken every six to ten passes for the subsequent layers. Contact pyrometers will be calibrated in accordance with approved calibration and control program documents.

(f)

Particular care shall be given to ensure that the weld region is free of all potential sources of hydrogen. The surfaces to be welded, filler metal, and shielding gas shall be suitably controlled.

to 1 CAN100702 Page 4 of 4 FIGURE 1-1 QUALIFICATION TEST PLATE Discard Transverse Side Bend Reduced Section Tensile t

F Transverse Side Bend HAZ Charpy V-Notch Transverse Side Bend Reduced Section Tensile Transverse Side Bend Discard LFUION WELD METAL HEAT AFFECTED 2' ZONE (HAZ)

NOTE Base metal Charpy impact specimens are not shown.

1CAN100702 Comparison of ASME Code Case N-504-2 and Appendix Q of ASME Section Xl with the Proposed Alternative of Attachment 2 for Preemptive Full Structural Weld Overlays to 1CAN 100702 Page 1 of 7 COMPARISON OF ASME CODE CASE N-504-2 AND APPENDIX Q OF ASME SECTION XI WITH THE PROPOSED ALTERNATIVE OF ATTACHMENT 2 FOR PREEMPTIVE FULL STRUCTURAL WELD OVERLAYS Code Case N-504-2 and Appendix Q of ASME Section Xl Proposed Alternative of Attachment 2 Code Case N-504-2 provides requirements for reducing a defect to a The proposed alternative of Attachment 2 provides requirements for flaw of acceptable size by deposition of weld reinforcement (weld installing a preemptive full structural weld overlay by deposition of weld overlay) on the outside surface of the pipe using austenitic stainless reinforcement (weld overlay) on the outside surface of the item using Nickel steel filler metal as an alternative to defect removal. Code Case Alloy 52M filler metal. Attachment 2 is applicable to dissimilar metal welds N-504-2 is applicable to austenitic stainless steel piping only.

associated with ferritic, stainless steel, and nickel alloy materials. It is also According to Regulatory Guide 1.147, the provisions of Non-applicable to similar metal welds in austenitic stainless steels. The mandatory Appendix Q of ASME Section XI must also be met when proposed alternative of Attachment 2 is based on Code Case N-740.

using this Case. Therefore, the Code Case N-504-2 requirements presented below have been supplemented by Appendix Q of ASME Section XI.

General Requirements 1.0 General Requirements Code Case N-504-2 and Appendix Q are only applicable to P-No. 8 As specified in paragraph 1.0(a) of Attachment 2, the proposed alternative austenitic stainless steels.

is applicable to dissimilar metal 82/182 welds joining P-No. 1 to P-No. 8 materials.

Basis: Code Case N-504-2 and Appendix Q are applicable to austenitic weld overlays of P-No. 8 austenitic stainless steel materials. Based on Code Case N-740, the proposed alternative of Attachment 2 was specifically written to address the application of weld overlays over dissimilar metal welds.

According to paragraph (b) of Code Case N-504-2 as supplemented The weld filler metal and procedure requirements of Attachment 2, by Appendix Q, weld overlay filler metal shall be low carbon (0.035%

paragraph 1.0(b) are equivalent to Code Case N-504-2 and Appendix Q max.) austenitic stainless steel applied 360 degrees around the except as noted below:

circumference of the pipe, and shall be deposited using a Welding Procedure Specification for groove welding, qualified in accordance Weld overlay filler metal shall be austenitic Nickel Alloy 52M with the Construction Code and Owner's Requirements and (ERNiCrFe-7A) filler metal which has a chromium content of at least identified in the Repair/Replacement Plan.

28%.--

to 1 CAN 100702 Page 2 of 7 Code Case N-504-2 and Appendix Q of ASME Section X.

Proposed Alter ative of Attaclhrment 2 As an alternative to post~weld heat treatment, the provisions for "Ambient Temperature Temperbead Welding" may be used on the ferritic nozzle as described in Attachment 3.

Basis: The weld overlay will be deposited with ERNiCrFe-7 (Alloy 52M) filler metal. It has been included into ASME Section IX as F-No. 43 filler metals. Containing 28.0 - 31.5% chromium (roughly twice the chromium content of 82/182 filler metal), this filler metal has excellent resistance to PWSCC..This point has been clearly documented in EPRI Technical Report MRP-115, Section 2.2. Regarding the WPS, paragraph 1.0(b) of provides clarification that the WPS used for depositing weld overlays must be qualified as a groove welding procedure to ensure that mechanical properties of the WPS are appropriately established. Where welding is performed on ferritic nozzles, an ambient temperature temperbead WPS will be used. Suitability of an ambient temperature temperbead WPS is addressed in Section V.A.2 of this Request.

According to paragraph (e) of Code Case N-504-2 as supplemented by Appendix Q, the weld reinforcement shall consist of at least two weld layers having as-deposited delta ferrite content of at least 7.5 FN. The first layer of weld metal with delta ferrite content of at least 7.5 FN shall constitute the first layer of the weld reinforcement that may be credited toward the required thickness. Alternatively, first layers of at least 5 FN provided the carbon content is determined by chemical analysis to be less than 0.02%.

The weld overlay Attachment 2 is deposited using Nickel Alloy 52M filler metal instead of austenitic stainless steel filler metals. Therefore, the basis for crediting the first layer towards the required design thickness will be&'

based on the chromium content of the nickel alloy filler metal. According to paragraph 1.0(d) of Attachment 2, the first layer of Nickel Alloy 52M deposited weld metal may be credited toward the required thickness provided the portion of the layer over the austenitic base material, austenitic weld, and the associated dilution zone from an adjacent ferritic base material contains at least 24% chromium. The chromium content of the deposited weld metal may be determined by chemical analysis of the production weld or from a representative coupon taken from a mockup prepared in accordance with the WPS for the production weld.

Basis: The weld overlay will be deposited with ERNiCrFe-7 (Alloy 52M) filler metal. Credit for the first weld layer may not be taken toward the required thickness unless it has been shown to contain at least 24%

chromium. This is a sufficient amount of chromium to prevent PWSCC.

Section 2.2 of EPRI Technical Report MRP-1 15 states the following:

to 1 CAN 100702 Page 3 of 7 Code, Case N-504-2 and Appendix Q of ASMVE Section'XI

< '*Proposed Alternative of Attachment 2 "The only well explored effect of the compositional differences among the weld alloys on PWSCC is the influence of chromium. Buisine, et al.

evaluated the PWSCC resistance of nickel-based weld metals with various chromium contents ranging from about 15% to 30% chromium. Testing was performed in doped.steam and primary water. Alloy 182, with about 14.5% chromium, was the most susceptible. Alloy 82 with 18-20%

chromium took three or four times longer to crack. For chromium contents between 21 and 22%, no stress corrosion crack initiation was observed..."

Design and Crack Growth Considerations 2.0 Design and Crack Growth Considerations The design and flaw characterization provisions of Code Case The design and flaw evaluation provisions in the proposed alternative of N-504-2, paragraphs (f) and (g) as supplemented by Appendix Q are, Section 2.0 are the same as Code Case N-504-2 as summarized below:

supplemented in Appendix Q with the exceptions below. Note that the design and flaw evaluation provisions of Attachment 2 are based on founi) flaw.

Flaw chcer ation and the eval tiong flares based on tpostulated flaws insteadof as-found flaws. since the structural weld:

found flaw. Flaw evaluation of the existing flaws is based on overlays are being installed preemptively.

IWB-3640 for the design life.

For crack growth evaluations, a flaw with a depth of 75% and a Mulengthipquale t

circumferen ofl theale s o thaedindividua flaws o

circumference of 3600 will be assumed. The size of the assumed flaws length equal to the sum of the lengths of the individual flaws.

salb rjce oteedo h einlf fteoely rc shall be projected to the end of the design life of the overlay. Crack

" Circumferential flaws are postulated as 100% through-wall growth, including both stress corrosion and fatigue crack growth, shall for the entire circumference with one exception. When the be evaluated in the materials in accordance with IWB-3640. If the flaw combined length of circumferential flaws does not exceed is at or near the boundary of two different materials, evaluation of flaw 10% of the circumference, the flaws are only assumed to be growth in both materials is required.

100% through-wall for the combined length of the flaws.

For design, flaws shall be assumed to be 100% through the original wall

" For axial flaws 1.5 inches or longer, or for five or more axial thickness for the entire circumference.

flaws of any length, the flaws shall be assumed to be 100%

through-wall for the axial length of the flaw and entire Basis: Preemptive weld overlays are being installed in accordance with circumference of the pipe. to proactively address and mitigate any future PWSCC issues with the subject welds. Because these weld overlays are being (ii) For four or fewer axial flaws less than 1.5 inches in length, the installed preemptively and not as a repair, postulated flaws are being weld overlay thickness need only consist of two or more layers assumed. Regarding the crack growth analysis, a flaw originating from the of weld metal meeting the deposit analysis requirements.

inside diameter, with a depth of 75%, and a circumference of 360 degrees to 1CAN 100702 Page 4 of 7 Code Case N-504-2 and AppendixQ of ASME Section XI Proposed Alternative of Attachment 2 i

(iii)

The axial length and end slope of the weld overlay shall cover the weld and HAZs on each side of the weld, and shall provide for load redistribution from the item into the weld overlay and back into the item without violating applicable stress limits of the Construction Code. Any laminar flaws in the weld overlay shall be evaluated in the analysis to ensure that load redistribution complies with the above. These requirements, are usually met if the weld overlay extends beyond the projected

. flaw by at least 0.75 (Rt)112.

(iv) Unless specifically analyzed, the end transition slope of the overlay shall not exceed 450, and a slope of not more than 1:3 is recommended.

(v)

The overlay design thickness of items shall be based on the measured diameter, using only the weld overlay thickness conforming to the deposit analysis requirements. The combined wall thickness at the weld overlay, any planar flaws in the weld overlay, and the effects of any discontinuity (e.g.,

another weld overlay or reinforcement for a branch connection) within a distance of 0.75 (Rt)112 from the toes of the weld overlay, shall be evaluated and meet the requirements of IWB-,

IWC-, or IWD-3640.

(vi)

The effects of any changes in applied loads, as a result of weld shrinkage or existing flaws previously accepted by analytical evaluation shall be evaluated in accordance with IWB-3640, IWC-3640, or IWD-3640, as applicable.

will be assumed. A 75% through-wall flaw is the largest flaw that could remain undetected.."A preservice volumetric examination will be performed after application of the weld overlay using an ASME Section Xl, Appendix VIII [as implemented through PDI] examination procedure. This examination will verify that there is no cracking in the upper 25% of the original weld and base material. The preservice examination will also demonstrate that the assumption of a 75% through-wall crack is conservative. However, if any crack-like flaws are identified in the upper 25% of the original weld or base material by the preservice examination, then the as-found flaw (postulated 75% through-wall flaw plus the portion of the flaw in the upper 25%) will be used for the crack growth analysis. With regard to design, flaws are considered -to be 100% through the original weld and no structural credit-is taken for the weld. All other requirements are equivalent to Code Case N-504-2 assupplemented by Appendix Q.

Examination and Inspection 3.0 Examination and Inspection Code Case N-504-2 does not include requirements for acceptance, Section 3.0 of the proposed alternative specifies examination or inservice examination of weld overlays. Preservice requirements applicable to weld acceptance examinations, preservice examination is addressed. However, Appendix Q, Article Q-4000 examinations, and inservice examinations.

doesspecify requirements applicable to weld acceptance examinations, preservice examinations, and inservice examinations.

to 1 CAN 100702 Page 5 of 7 Code Case N-504-2 and Appendix Q of ASME Section XI PrpsdAtraieo ttachment 2 Acceptance Examination 3.0(a) Acceptance Examination Acceptance Examination The acceptance standards in paragraph 3.0(a)(3) of Attachment 2 are Q-41 00(c) states that the examination volume in Figure Q-4100-1 identical to those of paragraph Q-4100(c) except that paragraph 3.0(a)(3) includescrequirementstandeclarificationsothat areFnotrincluded-i shall be ultrasonically examined to assure adequate fusion (i.e.,

includes requirements and clarifications that are not included in adequate bond) with the base metal and to detect welding flaws, Appendix Q. First, it specifies that the ultrasonic examination shall be suchasinterbead) lack the fsion, metluon, tor d ack.

w ldna flaws, conducted at least 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after completing the third layer of the weld such as inter-bead lack of fusion, inclusions, or cracks. Planar flaws overlay when ambient temperature temperbead welding is used. Secondly, shall meet the preservice examination standards of Table it provides the following clarifications:

IWB-3514-2. Laminar flaws shall meet the following:

The interface C-D between the weld overlay and the weld includes the bond and the HAZ from the weld overlay.

In applying the acceptance standards, wall thickness "t," shall be the thickness of the weld overlay.

Basis: Appendix Q isapplicable to austenitic stainless steel materials only; therefore, ambient temperature temperbead welding would not be applicable. It is applicable to welding performed in the proposed alternative. When ambient temperature temperbead welding is performed, nondestructive examinations must be performed at least 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after completing the third layer of the weld overlay to allow sufficient time for hydrogen cracking to occur (if it is to occur). Technical justification for starting the 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after completion of the third layer of the weld overlay is provided in paragraph V.A.3.f of the Request. The other two changes are simply clarifications that were added to ensure that the examination requirements were appropriately performed.

Q-41 00(c)(1) states that laminar flaws shall meet the acceptance The acceptance standards in paragraph 3.0(a)(3)(i) of Attachment 2 are standards of Table IWB-3514-3.

identical to paragraph Q-4100(c)(1) except that paragraph 3.0 (a) (3) (i) includes the additional limitation that the total laminar flaw shall not exceed 10% of the weld surface area and that no linear dimension of the laminar flaw area exceeds 3.0 in.

to 1 CAN 100702 Page 6 of 7

~Code Cas6N-504-2 and Appendix Q of ASME Section Xl-

~,

Proposed Alternative of Attachment 2

+

Basis: These changes were made to provide additional conservatism to -

the weld overlay examination and to reduce the size of the un-inspectable volume beneath a laminar flaw. See paragraph V.A.3.c of the Request for additional information.

.Q-4100(c)(4) allows the performance of radiography in accordance The acceptance standards in paragraph 3.0(a)(3) of Attachment 2 do not with the Construction Code as an alternative to Q-4100(c) (3).

include the radiographic alternative of paragraph Q-4100(c)(4).

Basis: The UT examinations performed in accordance with the proposed alternative are in accordance with ASME Section Xl, Appendix VIII, Supplement 11 as implemented through the PDI. These examinations are considered more sensitive for detection of defects, either from fabrication or service-induced, than either ASME Section III radiographic or ultrasonic methods. Furthermore, construction type flaws have been included in the PDI qualification sample sets for evaluating procedures and personnel.

See Section V.A.3 of this Request for additional justification.

Preservice Inspection 3.0(b) Preservice Inspection Q-4200(b) states that the preservice examination acceptance The acceptance standards in paragraph 3.0(b)(2) of Attachment 2'are' standards of Table IWB-3514-2 shall be met for the weld overlay, identical to paragraph Q-4200(b) except paragraph 3.0(b)(2) includes the Cracks in the outer 25% of the base metal shall meet the design following statement: "In applying the acceptance standards, wall thickness, analysis requirements of Q-3000.

tw, shall be the thickness of the weld overlay."

Basis: This provision is actually a clarification that the nominal wall thickness of Table IWB-3514-2 shall be considered the thickness of the weld overlay. It must be remembered that the acceptance standards were originally written for the welds identified in IWB-2500. Because IWB-2500 does not address weld overlays, this clarification was provided to avoid any potential confusion. However, defining the weld overlay thickness as the nominal wall thickness of Table IWB-3514-2 has always been the practice since it literally becomes thenew design wall of the piping or component nozzle.

to lCAN 100702 Page 7 of 7 Code Case N-5O4-2 andAppendix Q0of ASME SectionXI ProposeI-d Alternative ofi ttachm*nt2'.

Pressure Testing 4.0 Pressure Testing (h) The completed repair shall be pressure tested in accordance The pressure testing requirements of Section 4.0 of Attachment 1 are with IWA-5000. A system hydrostatic test is required if the flaw similar to paragraph (h) of Code Case N-504-2 except that only a system penetrated the pressure boundary. A system leakage test may be leakage test per IWA-5000 is required.

performed if pressure boundary is not penetrated.

1CAN100702 Technical Basis for Alternatives to ASME Code Case N-638-1, Ambient Temperature Temperbead Welding to 1 CAN 100702 Page 1 of 3 TECHNICAL-BASIS FOR PROPOSED ALTERNATIVES TO ASME CODE CASE N-638-1 AMBIENT TEMPERATURE TEMPERBEAD WELDING

1.

Basis for Area Limitation Change to 500 Square Inches IWA-4600 and versions of ASME Code Case N-638 prior to Revision 3 contained a limit of 100 square inches for the surface area of a temperbead weld over ferritic base metal. The area limitation in Attachment 3 is 500 square inches. It is anticipated that some overlays applied under this alternative will be greater than 100 square inches but less than 500 square inches.

Technical justification for allowing weld overlays on ferritic materials with surface areas up to 500 square inches is provided in the white paper supporting the changes in ASME Code Case N-638-3 and EPRI Report 1011898 (Ref. 6). The ASME white paper notes that the original limit of 100 square inches in Code Case N-638-1 was arbitrary. It cites evaluations of a 12-inch diameter nozzle weld overlay to demonstrate adequate tempering of the weld heat affected zone (HAZ) (Section 2a of the white paper), residual stress evaluations demonstrating acceptable residual stresses in weld overlays ranging from 100 to 500 square inches (Section 2b of the white paper), and service history in which weld repairs exceeding 100 square inches were NRC approved and applied to DMW nozzles in several BWR and PWR (Section 3c of the white paper) applications. Some of the cited repairs are greater than 15 years old, and have been inspected several times with no evidence of any continued degradation.

It is important to note that the above theoretical arguments and empirical data have been verified in practice by extensive field experience with temperbead weld overlays, with ferritic material coverage ranging from less than 10 square inches up to and including 325 square inches. The table below provides a partial list of such applications.

Nozzle Diameter Approx..LAS Date

~

Plant Copoen (i n)oeae(n2 November 2006 SONGS Unit 3 PZR spray nozzle 5.1875 40 Safety/relief nozzles 8

60 PZR surge nozzle 12.75 110 November 2006 Catawba Unit 1 PZR spray nozzle 4

30 Safety/relief nozzles 6

50 PZR surge nozzle 14 120 November 2006 Oconee Unit 1 PZR spray nozzle 4.5 30-Safety/relief nozzles 4.5 30 PZR surge nozzle 10.875 105 HL Surge Nozzle 10.75 70 October 2006 McGuire Unit 2 PZR spray nozzle 4

30 Safety/relief nozzles 6

50 PZR surge nozzle 14 120 April 2006 Davis-Besse Hot leg drain nozzle 4

16 to 1 CAN 100702 Page 2 of 3 February 2006 SONGS Unit 2 PZR spray nozzle Safety/relief nozzles 8

6 50 28 November 2005 Kuosheng Unit 2 Recirc. outlet nozzle 22 250 April 2004 Susquehanna Unit 1 Recirc; inlet nozzle 12 100 Recirc. outlet nozzle 28 325 November 2003 TMI Unit 1 Surge line nozzle 11.5 75 October 2003 Pilgrim.

Core spray nozzle 10 50 CRD return nozzle 5

20 October 2002 Peach Bottom Core spray nozzle 10 50 Recirc. outlet nozzle 28 325 Units 2 & 3 CRD return nozzle 5

20 October 2002 Oyster Creek Recirc. outlet nozzle 26 285 December 1999 Duane Arnold Recirc. inlet nozzle 12 100 June 1999 Perry Feedwater nozzle 12 100 June 1998 Nine Mile Point Unit 2 Feedwater nozzle 12 100 March 1996 Brunswick Units 1 & 2 Feedwater nozzle 12 100 February 1996 Hatch Unit 1 Recirc. inlet nozzle 12 100 January 1991 River Bend Feedwater nozzle 12

100, March 1986 Vermont Yankee Core spray nozzle 10 50 It can be seen from the information above that the original DMW weld overlay was applied over 20 years ago, and weld overlays with low alloy steel coverage in the 100-square inch range have been in service for 5 to 15 years. Several overlays have been applied with low alloy steel coverage significantly greater than the 100 square inches. These overlays have been examined with PDI qualified techniques, in some cases multiple times, and none have shown any signs of new cracking or growth of existing cracks.

2.

Clarification of Charpy V-Notch Acceptance Criteria Paragraph 2.1() of Code Case N-638-1 states, "The average of the three HAZ impact tests shall be equal to or greater than the average values of the three unaffected base metal tests." However, the Charpy V-notch test acceptance criteria in Code Case N-638-1 is misleading and inconsistent with the specified acceptance criteria in Section XI applicable to other Class 1 components, since it implies that all three parameters - lateral expansion, absorbed energy, and percent shear fracture - must be equal to or exceed the base material values.

to 1 CAN 100702 Page 3 of 3 Code Case N-638-2 corrected paragraph 2.1) to state that Charpy V-notch acceptance criteria is based on the average lateral expansion values rather than the average of all three values. This change clarified the intent of the code case and aligned its Charpy V-notch acceptance criteria with that of Sections III and XI as demonstrated in the Code references provided below.

" ASME-Section III - NB-4330, Impact Test Requirements

• ASME Section XI - IWA-4620, Temperbead Welding of Similar Materials

• ASME Section XI - IWA-4630, Temperbead Welding of Dissimilar Materials The Attachment 3 acceptance criteria for Charpy V-notch testing of the weld HAZ is as specified in Code Case N-638-2. The ASME Section XI basis for this change is documented in the White Paper in ASME C&S Connect for Code Case N-638-2.

1CAN100702 Comparison of ASME Section XI Appendix VIII, Supplement 11 to Performance Demonstration Initiative (PDI) to 1 CAN 100702 Page 1 of 8 COMPARISON OF ASME SECTION XI APPENDIX VIII, SUPPLEMENT 11 TO PERFORMANCE DEMONSTRATION INITIATIVE (PDI) 1.0 SPECIMEN REQUIREMENTS 1.1 General.

The specimen set shall conform to the following No Change requirements.

(b) The specimen set shall consist of at least three specimens (b) The specimen set shall consist of at least three specimens having having different nominal pipe diameters and overlay thicknesses.

different nominal pipe diameters and overlay thicknesses. They shall They shall include the minimum and maximum nominal pipe include the minimum and maximum nominal pipe diameters for which the diameters for which the examination procedure is applicable. Pipe examination procedure is applicable. Pipe diameters within a range of 0.9 diameters within a range of 0.9 to 1.5 times a nominal diameter to 1.5 times a nominal diameter shall be considered equivalent. If the shall be considered equivalent. If the procedure is applicable to procedure is applicable to pipe diameters of 24 in. or larger, the specimen pipe diameters of 24 in. or larger, the specimen set must include at set must include at least one specimen 24 in. or larger but need not include least one specimen 24 in. or larger but need not include the the maximum diameter. The specimen set shall include specimens with maximum diameter. The specimen set must include at least one overlays not thicker than 0.1 in. more than the minimum thickness, nor specimen with overlay thickness within -0.1 in. to +0.25 in. of the thinner than 0.25 in. of the maximum nominal overlay thickness for which maximum nominal overlay thickness for which the procedure is the examination procedure is applicable.

applicable.

Basis: To avoid confusion, the overlay thickness tolerance contained in the last sentence was reworded.

(d) Flaw Conditions (1) Base metal flaws. All flaws must be cracks in. or near the butt (1) Base metal flaws. All flaws must be in or near the butt weld heat-weld heat-affected zone, open to the inside surface, and extending affected zone, open to the inside surface, and extending at least 75%

at least 75% through the base metal wall. Flaws may extend 100%

through the base metal wall. Intentional overlay fabrication flaws shall not through the base metal and into the overlay material; in this case, interfere with ultrasonic detection or characterization of the base metal intentional overlay fabrication flaws shall not interfere with flaws. Specimens containing IGSCC shall be used when available. At ultrasonic detection or characterization of the cracking. Specimens least 70 percent of the flaws in the detection and sizing tests shall be containing IGSCC shall be used when available, cracks and the remainder shall be alternative flaws. Alternative flaw mechanisms, if used, shall provide crack-like reflective characteristics and shall be limited by the following:

to 1 CAN 100702 Page 2 of 8 AppendixVill Supplement 11 :Qualfication Requirements forVIK PDI Program:

Full Structural OverlaidWrought Austenitic Piping Welds

'l'The Proposed Alternative to Supplement 11 Requirements (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-ellipticalmwith a tip width of less than or equal to 0.002 inches.

Basis: Paragraph 1.1(d)(1) 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 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.

The statement "intentional overlay fabrication flaws shall not interfere with ultrasonic detection or characterization of the base metal flaws" was included into paragraph 1.1(d)(1). Additionally, to avoid confusion, the phrase "and the remainder shall be alternate flaws" was added to the second to last sentence of this paragraph.

to 1CAN 100702 Page 3 of 8 (e) Detection Specimens (1) At least 20% but less than 40% of the flaws shall be oriented within +/- 20 deg. of the pipe axial direction. The remainder shall be oriented circumferentially. Flaws shall not be open to any surface to which the candidate has physical or visual access. The rules of IWA-3300 shall be used to determine whether closely spaced flaws should be treated as single or multiple flaws.

(1) At least 20% but less than 40% of the base metal flaws shall be oriented within +/- 20 deg. of the pipe axial direction. The remainder shall be oriented circumferentially. Flaws shall not be open to any surface to which the candidate has physical or visual access.

Basis: The requirement for axially oriented overlay fabrication flaws in paragraph 1.1 (e)(1) was excluded from the PDI Program as an improbable scenario. Weld overlays are typically applied using automated Gas Tungsten Arc Welding techniques with the filler metal being applied in a circumferential direction. Because resultant fabrication induced discontinuities would also be expected to have major dimensions oriented in the circumferential direction axial overlay fabrication flaws are unrealistic.

The requirement for using IWA-3300 for proximity flaw evaluation in paragraph 1.1(e)(1) was excluded, instead, indications will be sized based on their individual merits.

(2) Specimens shall be divided into base and overlay grading units.

Each specimen shall contain one or both types of grading units.

(2) Specimens shall be divided into base metal and-overlay fabrication grading units. Each specimen shall contain one or both types of grading units. Flaws shall not interfere with ultrasonic detection or characterization of other flaws.

(a)(1) A base grading unit shall include at least 3 in. of the length of (a)(1) A base metal grading unit includes the overlay material and the outer the overlaid weld. The base grading unit includes the outer 25% of 25% of the original overlaid weld. The base metal grading unit shall extend the overlaid weld and base metal on both sides. The base grading circumferentially for at least 1. inch and shall start at the weld centerline and unit shall not include the inner 75% of the overlaid weld and base be wide enough in the axial direction to encompass one half of the original metal overlay material, or base metal-to-overlay interface, weld crown and a minimum of 0.50" of the adjacent base material.

Basis: The phrase "and base metal on both sides", was inadvertently included in the description of a base metal grading unit. The PDI program intentionally excludes this requirement because some of the qualification samples include flaws on both sides of the weld. This paragraph was also 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.

to 1 CAN 100702 Page 4 of 8 (a)(2) When base metal cracking penetrates into the overlay material, the base grading unit shall include the overlay metal within 1 in. of the crack location. This portion of the overlay material shall not be used as part of any overlay grading unit.

(a)(2) When base metal flaws penetrate into the overlay material, the base metal grading unit shall not be used as part of any overlay fabrication grading unit.

(a)(3) When a base grading unit is designed to be unflawed, at (a)(3) Sufficient unflawed overlaid weld and base metal shall exist on all least 1 in. of unflawed overlaid weld and base metal shall exist on sides of the grading unit to preclude interfering reflections from adjacent either side of the base grading unit. The segment of weld length flaws.

used in one base grading unit shall not be used in another base Basis: This paragraph was modified to require sufficient unflawed overlaid grading unit. Base grading units need not be uniformly spaced weld and base metal to exist on all sides of the grading unit to preclude around the specimen.

interfering reflections from adjacent flaws, rather than the 1 inch requirement.

(b)(1) An overlay grading unit shall include the overlay material and (b)(1) An overlay fabrication grading unit shall include the overlay material the base metal-to-overlay interface of at least 6 square inch. The and the base metal-to-overlay interface for a length of at least 1 inch.

overlay grading unit shall be rectangular, with minimum dimensions Basis: This paragraph was modified to define an overlay fabrication of 2 inches.Bai:Tipaarpwamoiidtdeieaovrafbicin grading unit as including the overlay material and the base metal-to-overlay interface for a length of at least 1 inch, rather than the 6 square inch requirement.

(b)(2) An overlay grading unit designed to be unflawed shall be (b)(2) Overlay fabrication grading units designed to be unflawed shall be surrounded by unflawed overlay material and unflawed base metal-separated by unflawed overlay material and unflawed base metal-to-overlay to-overlay interface for at least 1 in. around its entire perimeter, interface for at least 1 inch at both ends. Sufficient unflawed overlaid weld The specific area used in one overlay grading unit shall not be used and base metal shall exist on both sides of the overlay fabrication grading in another overlay grading unit. Overlay grading units need not be unit to preclude interfering reflections from adjacent flaws. The specific spaced uniformly about the specimen.

area used in one overlay fabrication grading unit shall not be used in another overlay fabrication grading unit. Overlay fabrication grading units need not be spaced uniformly about the specimen.

Basis: This paragraph 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.

-7 to 1 CAN 100702 Page 5 of 8 (b)(3) Detection sets shall be selected from Table VII1-S2-1. The minimum detection sample set is five flawed base grading units, ten unflawed base grading units, five flawed overlay grading units, and ten unflawed overlay grading units. For each type of grading unit, the set shall contain at least twice as many unflawed as flawed grading units.

(b)(3) Detection sets shall be selected from Table VIII-S2-1. The minimum detection sample set is five flawed base metal grading units, ten unflawed base metal grading units, five flawed overlay fabrication grading units, and ten unflawed overlay fabrication grading units. For each type of grading unit, the set shall contain at least twice as many unflawed as flawed grading units. For initial procedure qualification, 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.

Basis: This paragraph 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.

(f Sizing Specimen (1) The minimum number of flaws shall be ten. At least 30% of the (1) The minimum number of flaws shall be ten. At least 30% of the flaws flaws shall be overlay fabrication flaws. At least 40% of the flaws shall be overlay fabrication flaws. At least 40% of the flaws shall be open to shall be cracks open to the inside surface.

the inside surface. Sizing sets shall 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 for length sizing demonstrations shall (3) Base metal flaws used for length sizing demonstrations shall be be oriented circumferentially.

oriented circumferentially.

(4) Depth sizing specimen sets shall include at least two distinct (4) Depth sizing specimen sets shall include at least two distinct locations locations where cracking in the base metal extends into the overlay where a base metal flaw extends into the overlay material by at least material by at least 0.1 in. in the through-wall direction.

0.1 inch in the through-wall direction.

to 1 CAN 100702 Page 6 of 8 2.0 CONDUCT OF PERFORMANCE DEMONSTRATION The specimen inside surface and identification shall be concealed The specimen inside surface and identification shall be concealed from the from the candidate. All examinations shall be completed prior to candidate. All examinations shall be completed prior to grading the results grading the results and presenting the results to the candidate.

and presenting the results to the candidate. Divulgence of particular Divulgence of particular specimen results or candidate viewing of specimen results or candidate viewing of unmasked specimens after the unmasked specimens after the performance demonstration is performance demonstration is prohibited. The overlay fabrication flaw test prohibited.

and the base metal flaw test may be performed separately.

Basis: The PDI Program revised paragraph 2.0 allowing the overlay fabrication and base metal flaw tests to be performed separately.

2.1 Detection Test.

Flawed and unflawed grading units shall be randomly mixed.

Flawed and unflawed grading units shall be randomly mixed. Although the Although the boundaries of specific grading units shall not be boundaries of specific grading units shall not be revealed to the candidate, revealed to the candidate, the candidate shall be made aware of the candidate shall be made aware of the type or types of grading units the type or types of grading units (base or overlay) that are present (base metal or overlay fabrication) that are present for each specimen.

for each specimen.

2.2 Length Sizing Test (d) For flaws in base grading units, the candidate shall estimate the (d) For flaws in base metal grading units, the candidate shall estimate the length of that part of the flaw that is in the outer 25% of the base length of that part of the flaw that is in the outer 25% of the base metal wall wall thickness.

thickness.

to 1iCAN 100702 Page 7 of 8 ApniVIISujpplement 11: ~Qualification Requiremnits for PDI Pr~ogram:

Full Structural Overlaid Wrought Austenltic. Piping Welds The Proposed Alter~native to Sup~plemnent 11 Requirements 2.3 Depth Sizing Test.

For the depth sizing test, 80% of the flaws shall be sized at a (a) The depth sizing test may be conducted separately or in conjunction specific location on the surface of the specimen identified to the with the detection test.

candidate. For the remaining flaws, the regions of each specimen continig afla to~e szedshal beidetifed o th cadidte.

(b) When the depth sizing' test is conducted in conjunction with the continig afla to szed hal beidetifed of the flawdinae detection test and the detected flaws do not satisfy the requirements of The candidate shall determine the maximum depth 1o1f) addtina specmen shiepoiddtnh aniae h

each rgion.regions containing a flaw to be sized shall be identified to the candidate.

The candidate shall determine the maximum depth of the flaw in each region.

(c) For a separate depth sizing test, the regions of each specimen containing a flaw to be sized shall be identified to the candidate. The candidate shall determine the maximum depth of the flaw in each region.

3.0 ACCEPTANCE CRITERIA 3.1 Detection Acceptance Criteria.

Examination procedures, equipment, and personnel are qualified (a) Examination procedures are qualified for detection when; for detection when the results of the performance demonstration

()Alfaswti h cp ftepoeueaedtce n h satsfytheaccptncecrieri ofTale 111S2 fo b thdeteto results of the performance demonstration satisfy the acceptance criteria and false calls. The criteria shall be satisfied separately by te.

of Table ViII-S2-1 for false calls.

demonstration results for base grading units and for overlay grading units.

(2) At least one successful personnel demonstration has been performed meeting the acceptance criteria defined in (3b)..

(3) 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 callIs.

(4) The criteria in (2), (3) shall be satisfied separately by the demonstration results for base metal grading units and for overlay fabrication grading units.

to 1CAN100702 Page 8 of 8 Appendix Vill Supplement 11: Qua~lification Requirements for F~ull Structural Overlaid Wruh ustenitic Piping Welds PDI Program The Proposed Alternative to SupplIement 11 Requirements 1-Basis: The PDI Program allows procedure qualification to be performed separately from personnel and equipment qualification. Historical data indicate that, if ultrasonic detection or sizing procedures are thoroughly tested, personnel and equipment using those procedures have a higher probability of successfully passing a qualification test. In an effort to-increase the passing rate, PDI has elected to perform procedure qualifications separately in order to assess and modify essential variables that may affect overall system capabilities. For a procedure to be qualified, the PDI program requires three times as many flaws to be detected (or-sized) as shown in Supplement 11 for the entire ultrasonic system. The personnel and equipment are still required to meet Supplement 11.

3.2 Sizing Acceptance Criteria.

(a) The RMS error of the flaw length measurements, as compared (a) The RMS error of the flaw length measuremrents,.as Compared to the to the true flaw lengths, is less than or equal to 0.75 inch. The true flaw lengths, is less than or equal to 0.75 inch. The length of base length of base metal cracking is measured at the 75% through-metal flaws is measured at the 75% through-base-metal position.

base-metal position.

(b) All extensions of base metal cracking into the overlay material This requirement is omitted.

by at least 0.1 inch. are reported as being intrusions into the overlay material.

Basis: The requirement for reporting all extensions of cracking into the o y roverlay is omitted from the PDI Program because it is redundant to the RMS calculations performed in paragraph 3.2(c), and its presence adds confusion and ambiguity to depth sizing as required by paragraph 3.2(c).

This also makes the weld overlay program consistent with the Supplement 2 depth sizing criteria.

(c) The RMS error of the flaw depth measurements, as compared (b) The RMS error of the flaw depth measurements, as compared to the to.the true flaw depths, is less than or equal to 0.125 inch.

true flaw depths, is less than or equal to 0.125 inch.

1 CAN100702 List of Regulatory Commitments to 1 CAN 100702 Page 1 of 1 List of Regulatory Commitments The following table identifies those actions committed to by Entergy in this document. Any other statements in this submittal are provided for information purposes and are not considered to be regulatory commitments.

TYPE (Check one)

SCHEDULED COMPLETION COMMITMENT DATE (If Required)

ONE-TIME CONTINUING ACTION COMPLIANCE Entergy will submit the following information to X

Within fourteen the NRC:

(14) days from Weld overlay examination results including completing the final ultrasonic a listing of indications detected, examinations of Disposition of indications using the the completed standards of ASME Section XI, Subsection weld overlays IWB-3514-2 and/or IWB-3514-3 criteria and, if possible, the type and nature of the indications, and A discussion of any repairs to the weld overlay material and/or base metal and the reason for the repairs Entergy will submit to the NRC a stress X

Prior to entry analysis summary demonstrating that the hot into Mode 4 leg piping nozzle will perform its intended following the design function after weld overlay installation.

ANO-1 refueling The stress analysis report will include results outage 1 R21 showing that the requirements of NB-3200 and NB-3600 of the ASME Code,Section III are satisfied. The stress analysis will also include results showing that the requirements of Subsection IWB-3000 of the ASME Code,Section XI, are satisfied. The results will show that the postulated crack including its growth in the nozzles will not adversely affect the integrity of the overlaid welds.