ML050270083

CFR 50.55A Review to Request RR-89-50 Alternative Temper Bead Welding Requirements for Pressurizer Pad Deposits

ML050270083
Person / Time
Site:	Millstone
Issue date:	01/26/2005
From:	Hartz L Dominion Nuclear Connecticut
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
04-279A, RG-1.147, Rev 13
Download: ML050270083 (29)

Text

Dominion Nuclear Connecticut, Inc.

~Miill\\toiw Power Station Kopc f,crry Rocid Wircrliird, C I. 06385 January 26, 2005 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 Ik Y borninion.

Serial No.:

04-279A Docket No.:

50-336 License No.:

DPR-65 NL&OS/PRW Rev 0 DOMINION NUCLEAR CONNECTICUT. INC. (DNC)

MILLSTONE POWER STATION, UNIT 2 10 CFR 50.55A REVISION TO REQUEST RR-89-50 ALTERNATIVE TEMPER BEAD WELDING REQUIREMENTS FOR PRESSURIZER WELD PAD DEPOSITS In a letter dated June 14, 2004, Dominion Nuclear Connecticut, Inc. (DNC), requested approval to use alternatives to the requirements of the American Society of Mechanical Engineers (ASME) Code,Section XI, 1998 Edition, Alternative Welding Requirements of IWA-4600.

Specifically, DNC proposed the use of temper bead welding requirements similar to those of ASME Code Case N-638, which is currently approved for use in accordance with U.S. NRC Regulatory Guide 1.147, Revision 13. In a phone conference with the NRC on January 5, 2005, it was determined that minor revisions to Request RR-89-50 were necessary. Accordingly, Attachment 1 has been revised to reflect the revisions discussed. This alternative will be used to apply a weld pad deposit should any half-nozzle repair/replacements be applied to the instrumentation nozzles of the Millstone Power Station Unit 2 (MPS2) pressurizer. DNC has determined pursuant to 10 CFR 50.55a(a)(3)(i) that the alternatives specified in Attachment 1 provide an acceptable level of quality and safety.

MPS2 is currently in the third 10-year inservice inspection (61) interval, which started on April 1, 1999. The 1989 Edition of Section XI with no Addenda applies to the IS1 program and the 1998 Edition of Section XI with no Addenda is used as the primary ASME Code Edition for Section XI Repair/Replacement program activities. These ASME Code requirements contain no provisions to address the application of a temper bead weld pad required for a half-nozzle repair/replacement activity on the pressurizer at MPS2 nor would these requirements allow this type of weld pad deposit without full postweld heat treatment. To perform this application, provisions of the ASME Code Section I l l, the 1992 Edition will also be used as part of the alternatives contained in this request.

During the spring 2005 refueling outage, bare metal boric acid examinations will be performed on pressurizer Alloy 182/600 instrumentation nozzles that are potentially subject to Primary Water Stress Corrosion Cracking (PWSCC). In order to address the potential need to apply a half-nozzle repair/replacement to the pressurizer for any identified leakage at these small bore nozzles, DNC plans to apply a temper bead weld pad deposit using the alternatives in this request.

As part of this type of repairh-eplacement activity, a temper bead weld pad of F-No. 43 material will need to be deposited on the outside surface of the pressurizer using an automatic or machine type

Serial No. 04-279A Request RR-89-50 Alternative Temper Bead Welding Requirements Page 2 of 2 Gas Tungsten Arc Welding (GTAW) process based on the alternatives provided in.

This request is being submitted for review and approval to provide for contingencies in support of potential pressurizer instrumentation nozzle repair/replacements that may be needed in future refueling outages for the remainder of the third 10-year IS1 interval or until the planned replacement of the pressurizer, which is presently scheduled for the fall 2006 refueling outage. The next refueling outage is scheduled for the Spring 2005.

Accordingly, DNC requests review and approval of this request by March 1, 2005.

If you should have any questions regarding this submittal, please contact Mr. Paul R.

Willoughby at (804) 273-3572.

Very truly yours, Vice President - Nuclear Engineering Attachment (1)

Request RR-89-50 Alternative Temper Bead Welding Requirements for Pressurizer Weld Pad Deposits Commitments contained within this letter: None cc:

U. S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406-1 41 5 Mr. V. Nerses Senior Project Manager U. S. Nuclear Regulatory Commission One White Flint North 1 1555 Rockville Pike Mail Stop 8C2 Rockville, MD 20852-2738 Mr. S. M. Schneider NRC Senior Resident Inspector Millstone Power Station

Serial No. 04-279A Docket No. 50-336 ATTACHMENT 1 ALTERNATIVE TEMPER BEAD WELDING REQUIREMENTS FOR PRESSURIZER WELD PAD DEPOSITS RELIEF REQUEST RR-89-50 DOMINION NUCLEAR CONNECTICUT, INC. (DNC)

MILLSTONE POWER STATION, UNIT 2

Serial No. 04-279A I Relief Request RR-89-50 Page 1 of 26 I 1. 0 2.0 3.0 4.0 5.0 6.0 7.0 1. 0 2.0 3.0 4.0 5.0 RELIEF REQUEST RR-89-50 ALTERNATIVE TEMPER BEAD WELDING REQUIREMENTS FOR PRESSURIZER WELD PAD DEPOSITS CONTENTS COMPONENT IDENTIFICATION...................................................................

2 CODE REQUIREMENTS................................................................................

3 CODE REQUIREMENTS FOR WHICH ALTERNATIVES ARE REQUESTED.........................................................................................

3 BASIS FOR THE REQUESTED ALTERNATIVES..........................................

9 ALTERNATIVE REQUIREMENTS..................................................................

13 DURATION OF THE PROPOSED ALTERNATIVE........................................

18 PRECEDENTS...............................................................................................

18 ENCLOSURE 1 :

Dissimilar Metal Welding Using Ambient Temperature GENERAL REQUIREMENTS......................................................................

19 WELDING QUALIFICATIONS.....................................................................

19 2.1 Procedure Qualification.....................................................................

20 2.2 Performance Qualification.................................................................

21 WELDING PROCEDURE REQUIREMENTS..............................................

21 EXAM I N AT1 ON............................................................................................

21 DOCUMENTATION.....................................................................................

22 Machine GTAW Temper Bead Technique FIGURE 1 TYPICAL HALF-NOZZLE REPAIWREPLACEMENT WITH A WELD PAD DEPOSIT.................................................................

23 FIGURE 2:

QUALIFICATION TEST PLATE.....................................................

24 FIGURE 3: AUTOMATIC OR MACHINE (GTAW) TEMPER BEAD WELDING............................................................................

25

Serial No. 04-279A I Relief Request RR-89-50 Page 2 of 26 I RELIEF REQUEST RR-89-50 ALTERNATIVE TEMPER BEAD WELDING REQUIREMENTS FOR PRESSURIZER WELD PAD DEPOSITS Proposed Alternative In Accordance with 10 CFR 50.55a(a)(3)(i)

- Alternative Provides Acceptable Level of Quality and Safety -

1.O COMPONENT IDENTIFICATION:

Pressurizer Instrumentation Nozzles (8) - Potential Weld Pad Deposits For The Following Nozzles:

Level Nozzles (4): Four 1-inch, schedule 160 level nozzles, two in the upper head and two in the lower head, all fabricated from SB-166 Ni-Cr-Fe alloy with SA-182 (F-316) stainless steel socket weld safe ends.

Pressure Nozzles (2): Two 1-inch, schedule 160 pressure nozzles in the upper head, all fabricated from SB-166 Ni-Cr-Fe alloy with SA-182 (F-316) stainless steel socket weld safe ends.

Temperature Nozzles (2): Two 1 -inch, schedule 160 temperature nozzles, one in the top head (steam space) and one in the lower shell (heater area),

both fabricated from SB-166 Ni-Cr-Fe alloy with SA-182 (F-316) stainless steel socket weld safe ends.

Code Class:

1 System:

Reactor Coolant System (RCS)

Code Category:

B-P, All Pressure Retaining Components Code Item Nos.:

Pressurizer:

B15.20, Pressure Retaining Boundary [system leakage test & visual, VT-2 examination each refueling outage]

B15.21, Pressure Retaining Boundary [system hydrostatic test (system leakage test per code case N-498-1) & visual, VT-2 examination one test per interval]

Serial No. 04-279A 1 Relief Request RR-89-50 Page 3 of 26 I

References:

1.

Pressurizer - 1968 Edition, American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code), Section Ill, Class A Vessels, with Addenda through Summer 1969.

2.

1989 Edition, ASME Code,Section XI, No Addenda

3.

1998 Edition, ASME Code,Section XI, No Addenda

4. 1992 Edition, ASME Code, Section Ill, and the 1992 Edition with the 1992 Addenda of Section II for materials.

2.0 CODE REQUIREMENTS:

The Construction Code of record for the Millstone Power Station Unit 2 (MPS2) pressurizer is the 1968 Edition of ASME Section Ill with Addenda through the Summer of 1969 (reference 1). MPS2 is currently in its third 10-year inservice inspection (ISI) interval using the ASME Section XI, 1989 Edition, No Addenda (reference 2) for the IS1 program and the ASME Section XI, 1998 Edition, No Addenda (reference 3) for the Section XI RepaidReplacement program.

For repairheplacement activities associated with welding, brazing, metal removal, and installation associated with Construction Code and Owner's Requirements paragraph IWA-4421 (a), states the following:

"Welding, brazing, metal removal, and installation activities shall be performed in accordance with the Owner's Requirements and the Construction Code of the component or system, except as provided in (b) and (c) below. lJ...

For the repairs to the pressurizer instrumentation nozzles, paragraph N-528.2 of reference 1 requires repairs be postweld heat treated (PWHT) in accordance with paragraph N-532 for the pressurizer. The PWHT requirements set forth therein would be difficult if not impossible to attain on a pressurizer in containment without distortion of the component. In addition, the existing instrumentation nozzle welds were not qualified with PWHT and cannot be so qualified at this time.

Consequently, the proposed repairs will be conducted in accordance with the 1998 Edition of ASME Section XI (reference 3) as applicable, the 1992 Edition of Section I I I (reference 4) as applicable, and alternative requirements discussed below.

3.0 CODE REQUIREMENTS FOR WHICH ALTERNATIVES ARE REQUESTED:

Dominion Nuclear Connecticut, Inc. (DNC) will be performing boric acid inspections on the pressurizer instrumentation nozzles during the refueling outage. If any of these nozzles show evidence of leakage, repairheplacement activities will be performed using a half-nozzle repairheplacement method. Per subparagraph IWA-

Serial No. 04-279A I Relief Request RR-89-50 Page 4 of 26 I 4421(a) of Section XI (reference 3), welding must be done in accordance with the Owners Requirements and the Construction Code. Therefore, for any repair to the ferritic material of the pressurizer, paragraph N-532 of ASME Section Ill (reference

1) PWHT would be required for the repair welding. As pointed out above, the PWHT parameters required by N-532 would be difficult to achieve on a pressurizer in containment and would pose a significant risk of distortion to the geometry of the vessel and its nozzles. In addition, application of paragraph N-532 could expose the existing inside diameter J-groove welds to PWHT for which they were not originally qualified.

Because of the inability to comply with the requirements of the original Construction Code, the rules of ASME Section Ill, 1992 Edition (reference 4) will apply to the repairs. Therefore, for any pressurizer instrumentation nozzles where boric acid deposits identify evidence of leakage, the assumption will be made that flaws are present in the area of the internal J-groove weld that attaches these nozzles to the inside surface of the vessel, and a repairheplacement will be performed. The repairheplacement will consist of a half-nozzle repairheplacement with a weld pad deposit made of F-No. 43 material to be welded to the vessel outside surface prior to attaching a new external J-groove partial penetration weld using a half-nozzle repairheplacement design. (See Figure 1 : Typical Half-Nozzle Repair/Replacement With A Weld Pad Deposit).

For this type of repair/

replacement, welding to the vessel external surface, paragraph NB-4622 of Section Ill would require a postweld stress relief heat treatment for the repair weld or alternatively, use of the temper bead weld technique.

The temper bead procedure requirements, including preheat and postweld heat soaks contained in NB-4622, would be difficult to achieve in containment and are not necessary to produce a sound repair weld given the capabilities of the proposed alternative temper bead procedure below. Therefore, pursuant to 10 CFR 50.55a(a)(3)(i),

DNC requests to use an ambient temperature temper bead method of welding in accordance with the requirements of the 1992 Edition of ASME Section Ill, NB-4622 and alternatives to these requirements contained in this request.

The requirements of paragraphs NB-4622 and NB-5244 of the 1992 Edition of ASME Section Ill (reference 4), and IWA-4540 of the 1998 Edition of ASME Section XI (reference 3) are also applicable to the repairs. As an alternative to these requirements, the requirements of, Dissimilar Metal Welding Using Ambient Temperature Machine GTAW Temper Bead Technique, identified in Enclosure 1 of this attachment will be used. The requirements in Enclosure 1 are similar to the those contained in ASME Code Case N-638, Similar and Dissimilar Metal Welding Using Ambient Temperature Machine GTAW Temper Bead Technique Section XI, Division 1, which is currently approved for use in U. S. NRC Regulatory Guide 1.147, Revision 13. One of the conditions for the use of Code Case N-638 is that it is impractical, for operational or radiological reasons, to drain the component.

Because it is possible to drain the MPS2 pressurizer, Code Case N-638 cannot be used directly. Specifically, alternatives in this request are being proposed for the following articles, subarticles, paragraphs, and subparagraphs of ASME Section Ill.

Serial No. 04-279A I Relief Request RR-89-50 Page 5 of 26 I NB-4622.1 establishes the requirement for postweld heat treatment of welds including repair welds. In lieu of the requirements of this subparagraph, DNC proposes to utilize a temper bead weld procedure obviating the need for preheat and postweld stress relief.

NB-4622.2 establishes requirements for time at temperature recording of the PWHT and their availability for review by the Inspector. The requirement of this subparagraph will not apply because the proposed alternative does not involve PW HT.

NB-4622.3 discusses the definition of nominal thickness as it pertains to time at temperature for PWHT. The subparagraph is not applicable in this case because the proposed alternative involves no PWHT.

NB-4622.4 establishes the holding times at temperature for PWHT.

The subparagraph is not applicable in this case because the proposed alternative involves no PWHT.

NB-4622.5 establishes PW HT requirements when different P-number materials are joined. The subparagraph is not applicable because the proposed alternative involves no PWHT.

NB-4622.6 establishes PW HT requirements for non-pressure retaining parts. The subparagraph is not applicable in this case because the repairs in question will be to pressure retaining parts. Furthermore, the proposed alternative involves no PW H i.

NB-4622.7 establishes exemptions from mandatory PWHT requirements.

Subparagraphs NB-4622.7(a) through NB-4622.7(f) are not applicable in this case because they pertain to conditions that do not exist for the proposed repairs.

Subparagraph NB-4622.7(g) discusses exemptions to weld repairs to dissimilar metal welds if the requirements of subparagraph NB-4622.11 are met.

The ambient temperature temper bead repair is being proposed as an alternative to the requirements of subparagraph NB-4622.11.

NB-4622.8 establishes exemptions from PW HT for nozzle to component welds and branch connection to run piping welds. Subparagraph NB-4622.8(a) establishes criteria for exemption of PWHT for partial penetration welds. NB-4622.8(a)( 1) is applicable to the proposed repairs because the exemption criteria involves a requirement for buttering layers at least 1/4-inch thick and is applicable to the weld pad deposit made of F-No. 43 material, which will be applied to the pressurizer.

For the new partial penetration J-groove weld between the new half-nozzle and the pad, this exemption criteria will permit not having to PWHT the new J-groove weld.

Subparagraph 4622.8(b) does not apply because it discusses full penetration welds and the welds in question are partial penetration welds.

Serial No. 04-279A I Relief Request RR-89-50 Page 6 of 26 I NB-4622.9 establishes requirements for temper bead repairs to P-No. 1 and P-No.

3 materials and A-Nos. 1, 2, 10, or 11 filler metals. The subparagraph does not apply in this case because the proposed repairs will involve application of a weld pad deposit of F-No. 43 filler metals using an automatic or machine Gas Tungsten Arc Welding (GTAW) process instead of a shielded metal arc welding (SMAW) process.

NB-4622.10 establishes requirements for repair welding to cladding after PWHT.

The subparagraph does not apply in this case because the proposed repair alternative does not involve repairs to cladding.

NB-4622.11 discusses temper bead weld repair to dissimilar metal welds or buttering and would apply to the proposed repairdweld pad deposit.

Subparagraph NB-4622.11 (a) requires surface examination prior to repair in accordance with NB-5000. Prior to applying a weld pad deposit an ultrasonic examination in accordance with NB-5244 and a liquid penetrant examination will be performed including the area to be welded and a band around the area of at least 1-1/2 times the component thickness or 5-inches, whichever is less.

Subparagraph NB-4622.11 (b) contains requirements for the maximum extent of repair including a requirement that the depth of excavation for defect removal not exceed 3/8-inch in the base metal and the surface of the completed repair shall not exceed 100 square inches. The weld pad deposit proposed in the alternative will not require any excavation into the base metal and will be less than 100 square inches.

Subparagraph NB-4622.11 (c) discusses the repair welding procedure and requires procedure and welder qualification in accordance with ASME Section IX and the additional requirements of Article NB-4000.

The proposed alternative will satisfy this requirement. In addition, NB-4622.11 (c) requires that the Welding Procedure Specification include the following requirements:

P NB-4622.11(c)(l) requires the area to be welded be suitably prepared for welding in accordance with the written procedure to be used for the repair. The proposed alternative will satisfy this requirement.

P NB-4622.1 l(c)(2) requires the use of the shielded metal arc welding process with covered electrodes meeting either the A-No. 8 or F-No. 43 classifications.

The proposed alternative utilizes an automatic or machine applied GTAW process with bare non-consumable electrodes and bare filler wire meeting F-No. 43 classifications.

P NB-4622.11 (c)(3) discusses requirements for covered electrodes pertaining to hermetically sealed containers or storage in heated ovens.

These requirements do not apply because the proposed alternative uses

Serial No. 04-279A I Relief Request RR-89-50 Page 7 of 26 I bare non-consumable electrodes and bare filler wire that do not require storage in heated ovens to prevent pick up of moisture from the atmosphere.

P NB-4622.11 (c)(4) discusses requirements for storage of covered electrodes during repair welding. These requirements do not apply because the proposed alternative utilizes bare non-consumable electrodes and bare filler wire, which do not require any special storage conditions to prevent the pick up of moisture from the atmosphere.

P NB-4622.11 (c)(5) requires preheat to a minimum temperature of 350°F prior to repair welding. The proposed ambient temperature temper bead alternative does not require an elevated temperature preheat.

P NB-4622.11 (c)(6) establishes requirements for electrode diameters for the first, second, and subsequent layers of the repair welds and requires removal of the weld bead crown before deposition of the second layer.

Because the proposed alternative controls the tempering process by precise control of heat input and bead placement, the 3/32, 1/8 and 5/32-inch electrodes that are required by NB-4622.11 (c)(6) and the requirement to remove the weld crown of the first layer, are unnecessary. Accordingly, the proposed alternative does not include these requirements.

P NB-4622.1 l(c)(7) requires a hydrogen bake out be performed on the preheated area by heating to 450°F to 550°F for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> after a minimum of 3/16-inch of weld metal has been deposited. The proposed alternative does not require this bake out because the use of the extremely low hydrogen GTAW temper bead procedure does not require the hydrogen bake out.

"u NB-4622.11 (c)(8) requires welding subsequent to the hydrogen bake out of NB-4622.11(~)(7) be done with a minimum preheat of 100°F and maximum interpass temperature of 350°F. The proposed alternative limits the interpass temperature to a maximum of 350°F and requires the area to be welded be at least 50°F prior to welding. These limitations have been demonstrated to be adequate for the production of sound welds with acceptable properties in both the weld and heat affected zone (HAZ).

Serial No. 04-279A I Relief Request RR-89-50 Page 8 of 26 I NB-4622.11 (d)(l) requires a liquid penetrant examination after the hydrogen bake out described in NB-4622.11 (c)(7).

The proposed alternative does not require the hydrogen bake because it is unnecessary for the very low hydrogen automatic or machine applied GTAW temper bead welding process. However, an ultrasonic I examination will be performed on the finished weld pad deposit in accordance with NB-5244 along with a liquid penetrant examination that will include a band around the area of the pad at least 1-1/2 times the component thickness or 5-inches, whichever is less, no sooner than 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after the weld pad has cooled to ambient temperature.

NB-4622.11 (d)(2) requires liquid penetrant and radiographic examinations of the repair welds after a minimum time of 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> at ambient temperature. Ultrasonic inspection is required if practical. The proposed alternative includes the requirement to inspect after a minimum of 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> at ambient temperature. Because the proposed weld pad deposit configuration is not practical to radiograph and examination requirements are provided for weld buildup in NB-5244, final inspection will be by the ultrasonic method coupled with an additional liquid penetrant examination.

I NB-4622.11 (d)(3) requires that all nondestructive examination be in accordance with NB-5000. The proposed alternative will comply with NB-5000 requirements. NDE personnel qualifications will meet either IWA-2300 or NB-5000 as these requirements are equivalent for this alternative.

NB-4622.11 (e) establishes the requirements for documentation of the weld repairs in accordance with NB-4130. The proposed alternative will comply with these requirements.

NB-4622.11 (f) establishes requirements for the procedure qualification test plate relative to the P-No. and Group No. and the postweld heat treatment of the materials to be welded.

The proposed alternative complies with these requirements, and with the additional requirements of the alternative that the root width and included angle of the cavity are stipulated to be no greater than the minimum specified for the repair. In addition, the location of the V-notch for the Charpy test is more stringently controlled in the proposed alternative than in NB-4622.1 l(9.

NB-4622.1l(g) establishes requirements for welder performance qualification relating to physical obstructions that might impair the welders ability to make sound welds, which is particularly pertinent to the SMAW manual welding process. The proposed alternative involves an automatic or machine GTAW process and requires welding operators be qualified in accordance with ASME Section IX. The use of a machine

Serial No. 04-279A 1 Relief Request RR-89-50 Page 9 of 26 I process eliminates concern about obstructions, which might interfere with the welders abilities since these obstructions will have to be eliminated to accommodate the welding machine. Obstructions in close proximity but not blocking the movements of the machine will have no effect on the ability of the operator or the machine to make sound and good quality welds.

Subparagraph NB-4453.4 of Section Ill requires examination of the repair weld in accordance with the requirements for the original weld. The welds being made per the proposed alternative will be in the form of a weld pad deposit as described by NB-4244(c) and will meet the weld design requirements of NB-3352.4(c). For these weld pad deposits, ultrasonic examination is required in accordance with NB-5244.

For the proposed alternative, the weld pad deposit will be examined by an ultrasonic method in accordance with NB-5244 and with a liquid penetrant examination that will include a band around the area of the pad at least 1-1/2 times the component thickness or 5-inches, whichever is less.

These examinations will be performed no sooner than 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after the weld pad has cooled to ambient temperature.

Subsubarticle IWA-4540 of ASME Section XI 1998 Edition (reference 3) requires a system hydrostatic test in accordance with IWA-5000 for welded repairs to the pressure retaining boundary. As discussed in more detail in Section 4.0 BASIS FOR THE REQUESTED ALTERNATIVES, item 4.8 below, the proposed alternative will utilize a system leakage test per IWA-5211 (a) in accordance with Code Case N-416-2 with one exception: radiographic examination is replaced with ultrasonic examination under the Section Ill requirements of this Case.

4.0 BASIS FOR THE REQUESTED ALTERNATIVES:

The alternative to NB-4622 requirements being proposed involves the use of an ambient temperature temper bead welding technique that avoids the necessity of traditional PWHT, preheat and postweld heat soaks.

The features of the alternative that make it applicable and acceptable for the contemplated repairs are enumerated below:

4.1. The proposed alternative will require the use of an automatic or machine GTAW temper bead technique without the specified preheat or postweld heat treatment of the Construction Code. The proposed alternative will include the requirements of paragraphs 1.O through 5.0 of Enclosure 1, Dissimilar Metal Welding Using Ambient Temperature Machine GTAW Temper Bead Technique. The alternative will be used to make a weld pad deposit to P-No. 3, pressurizer base material A-533, Gr. B Class 1 with F-No. 43, Alloy 52 weld filler material.

Serial No. 04-279A I Relief Request RR-89-50 Page 10 of 26 I 4.2. The use of an automatic or machine GTAW temper bead welding technique to avoid the need for postweld heat treatment is based on research that has been performed by EPRI and other organizations. (Reference, EPRI Report GC-111050, Ambient Temperature Preheat for Machine GTAW Temper Bead Applications, dated November 1998.) The research demonstrates that carefully controlled heat input and bead placement allow subsequent welding passes to relieve stress and temper the HAZ of the base material and preceding weld passes. Data presented in Tables 4-1 and 4-2 of the report show the results of procedure qualifications performed with 300°F preheats and 500°F post-heats, as well as with no preheat and post-heat. From that data, it is clear that equivalent toughness is achieved in base metal and heat affected zones in both cases. The temper bead process has been shown effective by research, successful procedure qualifications, and many successful repairs performed since the technique was developed. Many acceptable Procedure Qualification Records (PQRs) and Welding Procedure Specifications (WPSs) presently exist and have been used to perform numerous successful repairs.

These repairs have included all of the Construction Book Sections of the ASME Code, as well as the National Board Inspection Code (NBIC). The use of the automatic or machine GTAW process utilized for temper bead welding allows more precise control of heat input, bead placement, and bead size and contour than the manual SMAW process required by NB-4622. The very precise control over these factors afforded by the alternative provides more consistent and effective tempering and eliminates the need to grind or machine the first layer of the repair.

4.3. The NB-4622 temper bead procedure requires a 350°F preheat and a postweld soak at 450°F to 550°F for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> for P-No. 3 materials. Typically, these kinds of restrictions are used to mitigate the effects of the solution of monatomic hydrogen in ferritic materials prone to hydrogen embrittlement cracking. The susceptibility of ferritic steels is directly related to three factors:

1) the propensity of the material to transform to a crack susceptible microstructure; 2) the level of monatomic hydrogen present; and 3) the level of tensile stress. The P-No. 3 material of the pressurizer is able to produce martensite from the heating and cooling cycles associated with welding.

However, the proposed alternative mitigates all three factors without the use of elevated preheat and postweld hydrogen bake out by closely controlling the welding heat input, bead placement and minimizing the introduction of hydrogen in the welding process.

The 1\\18-4622 temper bead procedure requires the use of the SMAW welding process with covered electrodes. The low hydrogen electrodes, which are required by NB-4622, are a source of hydrogen even when very stringent electrode baking and storage procedures are followed.

Even ultra low hydrogen (H4) SMAW electrodes can introduce up to 4 ml of monatomic hydrogen (H) per 100 grams of deposited weld metal. The only shielding of the molten weld puddle and surrounding metal from moisture in the atmosphere (a source of hydrogen) is the evolution of gases from the flux and

Serial No. 04-279A 1 Relief Request RR-89-50 Page 11 of 26 I the slag that forms from the flux and covers the molten weld metal. As a consequence of the possibility for contamination of the weld with hydrogen, NB-4622 temper bead procedures require preheat and postweld hydrogen bake-out. However, the proposed alternative temper bead procedure utilizes an automatic or machine GTAW process, which is essentially free of hydrogen. The GTAW process relies on bare welding non-consumable electrodes and bare filler wire with no flux to trap moisture. An inert gas blanket positively shields the weld and surrounding material from the atmosphere and moisture it may contain. It produces by far the lowest hydrogen levels of any of the commonly used arc welding processes.

Typically, deposits are less than 1 mL per 100 grams of deposited weld metal.

To further reduce the likelihood of any hydrogen evolution or absorption, the alternative procedure requires particular care to ensure the weld region is free of all sources of hydrogen. The automatic or machine GTAW process will be shielded with welding grade argon (99.997% pure), which typically produces welds essentially free of hydrogen. A typical argon flow rate would be about 15 to 50 CFH and would be adjusted to assure adequate shielding of the weld without creating a venturi affect that might draw oxygen or water vapor from the ambient atmosphere into the weld.

4.4. The weld pad deposits used for the repairh-eplacements will not be subject to hydrogen embrittlement cracking due to the controlled nature of the automatic or machine GTAW process and the use of the F-No. 43 ERNiCrFe-7 filler metal with the temper bead technique that has been described above.

4.5. Final examination of the repair welds, that is the weld pad deposits, would receive an ultrasonic examination in accordance with NB-5244 and a liquid penetrant examination that will include a band around the area of the pad at least 1-1/2 times the component thickness or 5-inches, whichever is less.

These examinations will be performed no sooner than 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after the weld pad has cooled to ambient temperature and before final welding and machining of the new half-nozzle repairheplacement weld. Given the 3/8-inch limit on repair depth in the ferritic material that will not occur with the weld pad deposit, the delay before final examination would provide ample time for any hydrogen that did inadvertently dissolve in the ferritic material to diffuse into the atmosphere or into the nonferritic weld material, which has a higher solubility for hydrogen and is not susceptible to hydrogen embrittlement cracking. Thus, in the unlikely event that hydrogen induced cracking did occur while hydrogen was still present, it would be detected by the 48-hour delay in examinations.

4.6. Results of procedure qualification work undertaken to date indicate that the process produces sound and tough welds. Typical tensile test results have been ductile breaks in the weld metal and the base metal.

As shown below, Procedure Qualification Record (FRA-ANP PQR 7164) using P-No. 3, Group No. 3 base material exhibited improved Charpy V-notch

Serial No. 04-279A I Relief Request RR-89-50 Page 12 of 26 I 4.7.

properties in the HAZ from all three measures. Absorbed energy, lateral expansion and % shear area were all improved, compared to the unaffected base material.

PQR 7164 Unaffected Base Material (avg)

HAZ (avg) 50°F absorbed energy (ft-lbs.)

69, 55, 77 (67) 109, 98, 141 (1 16) 50°F lateral expansion (mils) 50, 39, 51 (47) 59, 50, 56 (55) 50°F shear fracture (YO) 30,25, 30 (28) 40, 40, 65 (48) 80°F absorbed energy (ft-lbs.)

78, 83, 89 (83) 189, 165, 127 (1 60) 80°F lateral expansion (mils) 55, 55, 63 (58) 75, 69, 60 (68) 80°F shear fracture (YO) 35,35,55 (42) 100,90,80 (90)

The absorbed energy, lateral expansion, and percent shear fracture were significantly greater for the HAZ than the unaffected base material at both test temperatures.

Welding procedure qualification fully supports the welding procedure specification. The Welding Procedure Qualification supporting the applicable Welding Procedure Specification (WPS) to be used for the repair weld that is the weld pad deposit is for P-No. 3 Group No. 3 base material welded with F-No. 43 filler metal. Using the WPS, the proposed alternative (Enclosure 1) provides a technique for applying a weld deposited pad to the external surface of the pressurizer that will produce

sound, permanent repair/replacements with an acceptable level of quality and safety.

4.8. IWA-4540 requires a system hydrostatic test in accordance with IWA-5000 for welded repairs to the pressure-retaining boundary.

In lieu of a system hydrostatic test, which must be conducted at pressures exceeding normal operating pressure, the proposed alternative relies on a system leak test in accordance with the provisions N-416-2 which is acceptable for use in accordance with U.S. NRC Regulatory Guide 1.147, Revision 13 with a condition for acceptance that the Provisions of IWA-5213, Test Condition Holding Times, 1989 Edition, are to be used, and which has been incorporated into the Millstone Power Station ASME Section XI Repair and Replacement Program WC 3. One exception to Code Case N-416-2 will be taken under this alternative to replace the Section Ill radiographic examination requirements with ultrasonic examination requirements under NB-5244. This exception is being taken because the proposed weld pad deposit configuration is not practical to radiograph and the requirements of NB-5244 provided for weld buildup are the most appropriate examination requirements for this configuration. This system leak test will be performed at nominal operating pressure and nominal operating temperature coupled with nondestructive testing of the proposed weld pad deposit that offers an

Serial No. 04-279A I Relief Request RR-89-50 Page 13 of 26 I equivalent or higher confidence of the soundness of the weld. As discussed previously, the weld pad deposit will be ultrasonically examined in accordance with NB-5244 and with a liquid penetrant examination method prior to final machining and welding of the new half-nozzle repaidreplacement weld that will include a band around the area of the pad at least 1-1/2 times the component thickness or 5-inches, whichever is less. These examinations will be performed no sooner than 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after the weld pad has cooled to ambient temperature and these examinations will provide added assurance of sound welds when done in conjunction with the planned system leak test.

Since the proposed system leakage test requirements and nondestructive examinations are in accordance with an NRC approved version of Section I l l and Code Case N-416-2 with one exception: radiographic examination is replaced with ultrasonic examination under the Section Ill requirements of this Case, it is concluded that the proposed alternative provides an acceptable level of quality and safety.

4.9. To produce good, solid, quality welds control of the welding process is essential. The welding head that will be used for the weld pad deposits that will be made with the alternatives provided in this request has video capability for torch positioning and monitoring during welding. The operator observes the welding operation as well as observing each bead deposited prior to welding the next bead. The video clarity and resolution is such that the welding operator can observe a 1/2 mil diameter color contrast wire.

5.0 ALTER N AT1 V E R EQU I R EM ENTS :

Weld pad deposits needed to support half-nozzle repair/replacements that are planned as a contingency for the pressurizer instrumentation nozzles will be made in accordance with the requirements of IWA-4110, 4120, 4130, 4140, 4150, 4160, 4170, 4180, 4220, 4311, 4410, 4421, 4430, 4440, 4500, and 4600 of the 1998 Edition of ASME Section XI with the alternative requirements identified below.

The requirements of paragraphs NB-4622 and NB-5244 of the 1992 Edition of ASME Section Ill (reference 4), and IWA-4540 of the 1989 Edition of ASME Section XI (reference 2) are also applicable to the contemplated repairs. As an alternative to these requirements, the requirements of, Dissimilar Metal Welding Using Ambient Temperature Machine GTAW Temper Bead Technique, (Enclosure 1) will be used. Specifically, alternatives are being proposed for the following portions of ASME Section Ill and Section XI with the use of Enclosure 1.

I NB-4622.1 establishes the requirement for postweld heat treatment of welds including repair welds. In lieu of the requirements of this subparagraph, DNC proposes to utilize a temper bead weld procedure obviating the need for postweld stress relief.

NB-4622.2 establishes requirements for time at temperature recording of the PWHT and their availability for review by the Inspector. This requirement of this

Serial No. 04-279A I Relief Request RR-89-50 Page 14 of 26 1 subparagraph does not apply because the proposed alternative does not involve PWHT.

NB-4622.3 discusses the definition of nominal thickness as it pertains to time at temperature for PWHT. The subparagraph is not applicable in this case because the proposed alternative involves no PWHT.

NB-4622.4 establishes the holding times at temperature for PWHT.

The subparagraph is not applicable in this case because the proposed alternative involves no PWHT.

NB-4622.5 establishes PW HT requirements when different P-number materials are joined. This subparagraph is not applicable because the proposed alternative involves no PWHT.

NB-4622.6 establishes PW HT requirements for non-pressure retaining parts. The subparagraph is not applicable in this case because the repairs in question will be to pressure retaining parts. Furthermore, the proposed alternative involves no PWHT.

NB-4622.7 establishes exemptions from mandatory PWHT requirements. NB-4622.7(a) through NB-4622.7(f) are not applicable in this case because they pertain to conditions that do not exist for the proposed repairs. Subparagraph NB-4622.7(g) discusses exemptions to weld repairs to dissimilar metal welds if the requirements of subparagraph NB-4622.11 are met. The ambient temperature temper bead repair is being proposed as an alternative to the requirements of subparagraph NB-4622.11.

NB-4622.8 establishes exemptions from PWHT for nozzle to component welds and branch connections to run piping welds. Subparagraph NB-4622.8(a) establishes criteria for exemption of PWHT for partial penetration welds. NB-4622.8(a)( 1) is applicable to the proposed repairs because the exemption criteria involves a requirement for buttering layers at least 1/4 inch thick and is applicable to the weld pad deposit made of F-No. 43 material, which will be applied to the pressurizer, and then for the new partial penetration J-groove weld between the new half-nozzle and the pad. This exemption criteria will permit not having to PWHT the new J-groove weld. Subparagraph 4622.8(b) does not apply because it discusses full penetration welds and the welds in question are partial penetration welds.

NB-4622.9 establishes requirements for temper bead repairs to P-No. 1 and P-No. 3 materials and A-Nos. 1, 2, 10, or 11 filler metals. The subparagraph does not apply in this case because the proposed repairs will involve application of a weld pad deposit of F-No. 43 filler metals using an automatic or machine GTAW process instead of a shielded metal arc welding (SMAW) process.

Serial No. 04-279A I Relief Request RR-89-50 Page 15 of 26 I NB-4622.10 establishes requirements for repair welding to cladding after PWHT.

The subparagraph does not apply in this case because the proposed repair alternative does not involve repairs to cladding.

NB-4622.11 discusses temper bead weld repair to dissimilar metal welds or buttering and would apply to the proposed repairdweld pad deposits as follows:

0 Subparagraph NB-4622.11 (a) requires surface examination prior to repair in accordance with NB-5000. Prior to applying a weld pad deposit an ultrasonic examination in accordance with NB-5244 and a liquid penetrant examination will be performed including the area to be welded and a band around the area of at least 1-1/2 times the component thickness or 5-inches, whichever is less.

Subparagraph NB-4622.11 (b) contains requirements for the maximum extent of repair including a requirement that the depth of excavation for defect removal not exceed 3/8-inch in the base metal and the surface of the completed repair shall not exceed 100 square inches. The weld pad deposit proposed in the alternative will not require any excavation into the base metal and will be less than 100 square inches.

Subparagraph NB-4622.11 (c) discusses the repair welding procedure and requires procedure and welder qualification in accordance with ASME Section IX and the additional requirements of Article NB-4000.

The proposed alternative will satisfy this requirement. In addition, NB-4622.11 (c) requires that the Welding Procedure Specification include the following requirements:

NB-4622.11(c)(l) requires the area to be welded be suitably prepared for welding in accordance with the written procedure to be used for the repair. The proposed alternative will satisfy this requirement.

P NB-4622.1 l(c)(2) requires the use of the SMAW process with covered electrodes meeting either the A-No. 8 or F-No. 43 classifications. The proposed alternative utilizes GTAW with bare electrodes meeting the F-No. 43 classification.

NB-4622.11 (c)(3) discusses requirements for covered electrodes pertaining to hermetically sealed containers or storage in heated ovens.

These requirements do not apply because the proposed alternative uses bare non-consumable electrodes and bare filler wire that do not require storage in heated ovens because they will not pick up moisture from the atmosphere.

NB-4622.11 (c)(4) discusses requirements for storage of covered electrodes during repair welding. These requirements do not apply because the proposed alternative utilizes bare electrodes, which do not

Serial No. 04-279A Relief Request RR-89-50 Page 16 of 26 require any special storage conditions to prevent the pick up of moisture from the atmosphere.

NB-4622.11 (c)(5) requires preheat to a minimum temperature of 350°F prior to repair welding. The proposed ambient temperature temper bead alternative does not require an elevated temperature preheat.

NB-4622.11 (c)(6) establishes requirements for electrode diameters for the first, second, and subsequent layers of the repair weld and requires removal of the weld bead crown before deposition of the second layer.

Because the proposed alternative controls the tempering process by precisely controlling heat input and bead placement instead of the electrode diameter and removal of the weld crown, the 3/32, 1/8 and 5/32-inch electrodes required by NB-4622.11 (c)(6) and the requirement to remove the weld crown of the first layer are unnecessary. The proposed alternative does not include these requirements.

NB-4622.1 l(c)(7) requires a hydrogen bake out be performed on the preheated area by heating to 450°F to 550°F for four hours after a minimum of 3/16-inch of weld metal has been deposited. The proposed alternative does not require this hydrogen bake out because the use of the extremely low hydrogen GTAW temper bead procedure does not require the hydrogen bake out.

NB-4622.11 (c)(8) requires welding subsequent to the hydrogen bake out of NB-4622.11(~)(7) be done with a minimum preheat of 100°F and maximum interpass temperature of 350°F. The proposed alternative limits the interpass temperature to 350°F (maximum) and requires the area to be welded be at least 50°F prior to welding. This approach has been demonstrated to be adequate to produce sound welds with acceptable properties in both the weld and ferritic HAZ.

NB-4622.11 (d)(l) requires a liquid penetrant examination after the hydrogen bake out described in NB-4622.11 (c)(7).

The proposed alternative does not require the hydrogen bake because it is unnecessary for the very low hydrogen automatic or machine applied GTAW temper bead welding process. However, an ultrasonic examination will be performed on the finished weld pad deposit in accordance with NB-5244 along with a liquid penetrant examination that will include a band around the area of the pad at least 1-1/2 times the component thickness or 5-inches, whichever is less, which will be conducted no sooner than 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after the weld pad has cooled to ambient temperature.

NB-4622.11 (d)(2) requires liquid penetrant and radiographic examinations of the repair welds after a minimum time of 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> at ambient temperature. Ultrasonic inspection is required if practical. The

Serial No. 04-279A I Relief Request RR-89-50 Page 17 of 26 I proposed alternative includes the requirement to inspect after a minimum of 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> at ambient temperature. Because the proposed weld pad deposit configuration is not practical to radiograph and examination requirements are provided for weld buildup in NB-5244, final inspection will be by the ultrasonic method coupled with an additional liquid penetrant examination.

NB-4622.11 (d)(3) requires that all nondestructive examination be in accordance with NB-5000. The proposed alternative will comply with NB-5000 requirements. NDE personnel qualifications will meet either IWA-2300 or NB-5000 because these requirements are equivalent for this alternative.

NB-4622.11 (e) establishes the requirements for documentation of the weld repairs in accordance with NB-4130. The proposed alternative will comply with that requirement.

0 NB-4622.11 (f) establishes requirements for the procedure qualification test plate relative to the P-No. and Group No. and the postweld heat treatment of the materials to be welded. The proposed alternative complies with those requirements, and with the additional requirements of this alternative that the root width and included angle of the cavity are stipulated to be no greater than the minimum specified for the repair. In addition, the location of the V-notch for the Charpy test is more stringently controlled in the proposed alternative than in NB-4622.11 (f).

0 NB-4622.11(9) establishes requirements for welder performance qualification relating to physical obstructions that might impair the welders ability to make sound repairs, which is pertinent to the SMAW manual welding process. The proposed alternative involves a machine GTAW process and requires welding operators be qualified in accordance with ASME Section IX. The use of a machine process eliminates any concern about obstructions which might interfere with the welders abilities, because all such obstructions will have to be eliminated to accommodate the welding machine. Obstructions in close proximity, but not blocking the movements of the machine, will have no effect on the ability of the operator or the machine to make sound welds.

Serial No. 04-279A I Relief Request RR-89-50 Page 18 of 26 I Subparagraph NB-4453.4 of Section Ill requires examination of the repair weld in accordance with the requirements for the original weld. The welds being made per the proposed alternative will be in the form of a weld pad deposit as described by NB-4244(c) and will meet the weld design requirements of NB-3352.4(c).

For these weld pad deposits, ultrasonic examination is required in accordance with NB-5244. For the proposed alternative, the weld pad deposit will be examined by an ultrasonic method in accordance with NB-5244 and with a liquid penetrant examination that will include a band around the area of the pad at least 1-1/2 times the component thickness or 5-inches, whichever is less.

These examinations will be performed no sooner than 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after the weld pad has cooled to ambient temperature.

0 Subarticle IWA-4540 of ASME Section XI, 1998 Edition (reference 3),

requires a system hydrostatic test in accordance with IWA-5000 for welded repairs to the pressure-retaining boundary. As discussed in Section 4.0, BASIS FOR THE REQUESTED ALTERNATIVES, item 4.8, the proposed alternative will utilize a system leakage test in lieu of the system hydrostatic test in accordance with Code Case N-416-2 with one exception: radiographic examination is replaced with ultrasonic examination under the Section Ill requirements of this Case.

Per the 1989 Edition of ASME Section XI, paragraph IWB-2200(a), no preservice examination is required for weld pad deposits or instrumentation nozzles on the pressurizer, which are included under (Examination Category B-P). However, the NDE performed after welding will serve as a preservice examination record if needed in the future.

Furthermore, the inservice inspection requirement from Table IWB-2500-1, Examination Category B-P, is a Visual, VT-2 examination during a system leakage test that is conducted each refueling outage and the system hydrostatic test performed each 10-year interval. A system leakage test in lieu of the system hydrostatic test is currently being addressed by the use of Code Case N-498-1. Additionally, bare metal boric acid inspections are performed each refueling outage for 100% of the pressurizer instrumentation nozzles that are the subject of this alternative request. Currently, the ASME Code Committees are working on requirements for future examinations related to boric acid and RCS Alloy 182/600 cracking issues. DNC will continue to monitor ASMEs developing activities and determine the necessity of performing any additional or augmented inspections.

Based on the above information, DNC has concluded that the alternatives provided in this request will result in an acceptable level of quality and safety. Therefore, use of the proposed alternative ambient temperature temper bead weld technique in Enclosure 1 is an acceptable alternative in accordance with 10 CFR 50.55 a( a) (3) (i).

6.0 DURATION OF THE PROPOSED ALTERNATIVE:

Serial No.04-279 Relief Request RR-89-50 Page 19 of 25 The alternatives in this request will be applied for the remainder of the current third 10-year IS1 interval, which started on April 1, 1999 or until the planned replacement of the pressurizer that is scheduled for the Fall 2006 refueling outage.

7.0 PRECEDENTS

A similar request for the use of an alternative to temper bead welding requirements for pressurizer heater sleeve weld deposited pads was provided by Palo Verde Nuclear Generating Station, Units 1, 2, and 3 and was approved by the NRC on July 30, 2003 under TAC NOS. MB8973, MB8974, and MB8975, and Docket Nos.

STN 50-528, STN 50-529, and STN 50-530. Additionally, DNC has provided a similar request to allow the use of the automatic or machine GTAW alternative temper bead welding requirements for reactor vessel head penetration nozzle repairs at North Anna that was approved by the NRC on October 2, 2002 under TAC NO.MB4223 and Docket No. 50-336.

Serial No. 04-279A I Relief Request RR-89-50 Page 20 of 26 I ENCLOSURE 1 Dissimilar Metal Welding Using Ambient Temperature Machine GTAW Temper Bead Technique Dominion Nuclear Connecticut, Inc. (DNC) plans to perform as needed weld pad deposits on the pressurizer Instrumentation nozzles as part of a half-nozzle repairheplacement activity by welding to the pressurizer base material (P-No. 3 base material) with weld filler material F-No. 43, in accordance with the following:

1.O GENERAL REQUIREMENTS:

a.

The maximum area of the weld pad deposit on the finished surface will be less than 100 square inches, and the depth of the weld will not be greater than one-half of the ferritic base metal thickness.

b.

Repairheplacement activities on a dissimilar-metal weld 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.

c.

If a defect penetrates into the ferritic base material, repair of the base material, using a nonferritic weld filler material, may be performed provided the depth of repair in the base material does not exceed 3/8-inch.

d.

Prior to welding, the area to be welded and a band around the area of at least 1-1/2 times the component thickness or 5-inches, whichever is less, will be at least 50°F. This temperature shall be measured and recorded as part of the repairheplacement activity.

e.

Welding materials will meet the Owners Requirements and the Construction Code and will be reconciled to meet at least the 1992 Edition of Section II with the 1992 Addenda (reference 4) and any Code Cases specified in the repairheplacement plan. Welding materials will be controlled so that they are identified as acceptable until consumed.

f.

Peening will not be used.

2.0 WELDING QUALIFICATIONS:

The welding procedures and the welding operators shall be qualified in accordance with Section IX and the requirements of paragraphs 2.1 and 2.2.

Serial No. 04-279A Relief Request RR-89-50 Page 21 of 26 2.1 Procedure Qualification

a.

b.

C.

d.

e.

f.

The base materials for the welding procedure qualification will be P-No.

3 and Group No. 3, which is the same P-No. and Group No. as the low alloy steel pressurizer shell material to be welded. The base material will be postweld heat treated to at least the time and temperature that was applied to the materials being welded.

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

The maximum interpass temperature for the first three layers of the test assembly will be 150°F.

The ferritic steel P-No. 3 Group No. 3 base material test assembly cavity depth will be at least one-half the depth of the weld to be installed during the repair/t-eplacement activity, and at least 1 -inch. The test assembly thickness will be at least twice the test assembly cavity depth. The test assembly will be large enough to permit removal of the required test specimens. The test assembly dimensions surrounding the cavity will be at least the test assembly thickness, and at least 6-inches.

The qualification test plate will be prepared in accordance with Figure 2.

Ferritic base material for the procedure qualification test will meet the impact test requirements of the Construction Code and Owners Requirements.

Charpy V-notch tests of the ferritic heat-affected zone (HAZ) will be performed at the same temperature as the base metal test of subparagraph (e) above.

Number, location, and orientation of test specimens will be as follows:

(1) The specimens will be removed from a location as near as practical to a depth of one-half the thickness of the deposited weld metal.

The test coupons for HAZ impact specimens will be taken transverse to the axis of the weld and etched to define the HAZ.

The notch of the Charpy V-notch specimens will be cut approximately normal to the material surface in such a manner as to include as much HAZ as possible in the resulting fracture. When the material thickness permits, the axis of a specimen will 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 will be oriented parallel to the principal direction of rolling or forging.

Serial No. 04-279A Relief Request RR-89-50 Page 22 of 26 (3) The Charpy V-notch test will be performed in accordance with SA-370. Specimens will be in accordance with SA-370, Fig. 11, Type A. The test will consist of a set of three full-sized 10-mm x 10-mm specimens.

The lateral expansion, percent shear, absorbed energy, test temperature, orientation and location of all test specimens will be reported in the Procedure Qualification Record.

g.

The average values of the three HAZ impact tests will be equal to or greater than the average values of the three unaffected base metal tests.

2.2 Performance Qualification Welding operators will 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 will be deposited by the automatic or machine GTAW process.

b.

Dissimilar metal weld pad deposits shall be made using F-No. 43 ERNiCrFe-7 weld filler metal to P-No. 3 base metal.

c.

The ferritic steel area to be welded will be buttered with a deposit of at least three layers to achieve at least 1/8-inch overlay thickness as shown in Figure 3, steps 1 through 3, with the heat input for each layer controlled to within +lo% of that used in the procedure qualification test. Particular care will be taken in placement of the weld layers at the weld toe area of the ferritic material to ensure that the HAZ is tempered. Subsequent layers will 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 will be 350°F regardless of the interpass temperature during qualification with an ambient preheat temperature of at least 50°F. The interpass temperature for field applications shall be monitored and recorded using a contact pyrometer and I the preheat temperature shall be measured and recorded as part of the repaidreplacement activity.

4.0 EXAMINATION

a.

The final weld pad deposit surface and adjacent HAZ will be examined using the liquid penetrant and ultrasonic methods to the extent specified in Section 1.O, item d, when the completed weld has been at ambient temperature for at least 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />. The ultrasonic volume and liquid penetrant examination area I

Serial No. 04-279A Relief Request RR-89-50 Page 23 of 26 will include a band around the area of the pad at least 1-1/2 times the component thickness or 5-inches, whichever is less.

b.

Ultrasonic testing (UT) will be performed with scans from the outside surface of the pressurizer. UT coverage will include the weld pad deposit/weld metal buildup, the fusion zone, and the parent metal beneath the weld metal buildup to ensure freedom from lack of fusion and laminar defects per NB-5244 including a band around the area of the pad at least 1-1/2 times the component thickness or 5-inches, whichever is less.

c.

Areas from which weld-attached thermocouples have been removed will be ground and examined using a surface examination method. Thermocouples are not planned to be used as part of this alternative.

d.

NDE personnel will be qualified in accordance with either NB-5000 of (reference 4) or IWA-2300 of (reference 3) as these requirements are equivalent for this alternative.

Surface examination acceptance criteria will be in accordance with NB-5340 or NB-5350, as applicable. Ultrasonic examination acceptance criteria will be in accordance with NB-5330.

e.

5.O DOCUMENTATION :

Use of this alternative will be documented on a Form NIS-2A.

Serial No. 04-279A 1 Relief Request RR-89-50 Page 24 of 26 I i

Nozzle Remnant 1

1 FIGURE 1 :

A WELD PAD DEPOSIT TYPICAL HALF-NOZZLE REPAIWREPLACEMENT WITH

Serial No. 04-279A I Relief Request RR-89-50 Page 25 of 26 I Discard W A Z C harpy Reduced Section Tensile Discard Fusion line Wekl Matenal

/-.

F-No.43 GENERAL NOTE: Rase metal Chafpy impact specimens are not shown. This figure ikstrates a Dissimilar MsM WeM FIGURE 2: QUALIFICATION TEST PLATE

Serial No. 04-279A I Relief Request RR-89-50 Page 26 of 26 I Step 1: Deposit Inyer one with first tayar wald parameters used in qualification.

Stbp 2: Deposit layer two with second knyycr wdd parameters uscd in qualification. NOTE:

Particular care shall be raken in application of the second layer at tha wold toe to mwre that tho wold rnatal and HA2 of tho base motol arc k m p W d

• Step 3: Ooposit layor thraa wirh third layer wold parametfirs used in qualificletion. NOTE Particular caw shell be taken in application of d layer at ihe weld toe to ansura that thc weld mctol and HAZ aT the b b ~ e metal are tcrnpcrod.

Slep 4: Subseqitent layom to be deposited as qunlificd, with heat input Iws than or aquai to that qualified in tho tcst assembly. NOTE:

Penicuier care shall bc taken in application of the fill layers to preserve the temper of the weld metal and HA;L.

GENERAL NOTE: The illustrotion uhuve is for dissimita metal welcliiig using Q F-No. 43 Filler material, For dissirniler-moral welding, only the fctritic bas@ rnclal is required to be welded using steps I through 3 of the temperbead welding technique.

FIGURE 3:

AUTOMATIC OR MACHINE (GTAW) TEMPER BEAD WELDING