ULNRC-05385, Response Regarding 10 CFR 50.55a Request for Relief from ASME Section XI Repair and Replacement Requirements: Proposed Alternatives for Application of Structural Weld Overlays to Pressurizer Nozzle Welds

Response Regarding 10 CFR 50.55a Request for Relief from ASME Section XI Repair and Replacement Requirements: Proposed Alternatives for Application of Structural Weld Overlays to Pressurizer Nozzle Welds

ML070990115
Person / Time
Site:	Callaway
Issue date:	03/26/2007
From:	Fitzgerald D AmerenUE
To:	Document Control Desk, NRC/NRR/ADRO
References
ULNRC-05385
Download: ML070990115 (12)

Text

AmerenUE PO Box 620 Callaway P/ant Fulton, MO 65251 March 26, 2007 U LNRC-053S5 10 CFR 50.55a U.S. NuIclear1 Regu11ltory Comm11ission Attn: DocLumen~t C'ontrol Desk M/ail Stop PI- 137 Washingtoni, DC 20555-0001 L~adies and Gentlemen:

D)OCKET NUMBER 50-483 UNION ELECTRIC COMPANY W~mereilCALLAWAY UERESPONSE PLANT TO REQUEST FOR ADDITIONAL INFORMATION REGARDING 10 CFR 50.55ai REQUEST FOR RELIEF FRON' ASME SEKCTION XI REPAIR AND REPLACEMENT REQUIREMENTS:

PROPOSED ALTERNATIVES FOR APP~LICATION O1F STRUCTURA,-L WELD OVERLAYS TO PRESSURIZER NOZZLE WELDS Reference 1: AmerenUE letter ULNRC-05292, "RequLest For Relief fr-om ASME Section X1 Repair and Replacement Requirlemen~lts: Proposed Alternatives for Applicationi of StruIctura-l Weld Overlays to Pressurizer Nozzle Welds," dated 14 Auuu'Lst 2006.

By letter dated 14 August 2006 (Reference I), and lpursuant to 10 CFR 50.55a(a)(3),

AmerenUE (Union Electric Company) suibmitted a requeIst for relief from identified requirements of Section X1 of the American Society of Mechanical Engineers (ASME)

Boiler and Pressure Vessel Code, as needed for Support of the planned installation of full Structural weld overlays for certain pressuri'zer- nozzle wvelds at Callaway plant. The relief request, which ISCurrently under review by the NRC staff, would be applicable to Callaway Plant's Repair/Replacemnent program (as established by the ASME Section X1 Code), and inv'olves utilization of an alternate approach to ASME Section X1 requirements in connection wvith the Installation of the weld overlays.

Specifically per the 10 CFR 50.55a (rellet.) request, AmnerenijE proposes to implement alternative requirements in Hlie of requirements contained in ASME Section X1 IWA-441 0 (and its referenced original Construction Code for the reactor coolant systemn pressurizer and attached piping at Callaway), IWA-4430, IWA-4520(a),

IWA-4530, JWA-4600, and Table IWB-2500-1 (Examination Categories B-F and B-J), in order to provide for the installation and examiniation of full structural weld overlays for nozzle-to-safe end dissimilar metal and safe end-to-piping stainless steel butt welds associated wvith the pressurizer nozzles and connected piping. The overlays are a pre-emptive measure for addressing primary water stress corrosion cracking concerns that a subsidiary oflAmeren Corporation AN-7

ULNRC-05385 March 26, 2007 Page 2 of 4 have been identi fied by the industry for welds associated with Alloy 600/82/182 components exposed to pressurized waler reactor primary coolant. The proposed alternative requirements to be implemented have been determined to be appropriate for application aiid examination of the needed overlays, and will provide an acceptable level of quality and safety as required by 10 CFR 50.55a(a)(3)(i). Supporting information and the essential details, incIluding justification for the request, were provided in the relief request document itself which was submitted as an attachment to the letter of Reference

1. The wveld overlays addressed by the relief request are to be installed during the next refueling outage for Callaway, i.e., Refuiel 15 which is scheduled for April 2007.

During the NRC staff s review of the subject relief request, several questions were identified and they were electronically provided to AmerenUE as a request:for additional inform-ation (RAI). Responses to the NRC's RAI questions are hereby provided in Attachment I. It should also be noted that, subsequent to AmerenUE's submittal of the subject relief request, somne corrections were identified to be needed for the relief request documnent that was submitted. These corrections were verbally discussed with the NRC staff and also identified and provided in Attachment 1.

It may be noted that twvo new regulatory commitments are made in Attachment 1, and these commitments are identi fied and summarized in Attach-ment 2.

Please contact me at 573-676-8763 or Dave Shafer at 314-554-3104 or 573-676-4722 for any questions You may regarding these rellief requests.

Sincerely, David T. Fitzgerald Manager - Regulatory Affairs TBE/j dg Attachments: 1) Responses to NRC RAI Questions (and Correction of Information)

Regarding 10 CFR 50.5 5a(a)(3)(i) Request for Planned Installation of

.Full Structural Weld Overlays for Pressurizer Nozzle Welds

2) List of Commitments

ULNRC-05 385 March 26, 2007 Page 3 of 4 cc: U.S. Nuclear Regulatory Commission (Original and I copy)

Attn: Documnent Control Desk M/ail Stop P1-137 Washington, DC 20555-0001 N/Ir. Bruce S. NMallett Regional Administrator U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-4005 Senior Resident Inspector Callaway Resident Office U.S. Nuclear Regulatory Commission 8201 NRC Road Steedman, MO 65077 Mr. Jack N. Donohew (2 copies)

Licensing Project Manager, Callaway Plant Office of Nuclear Reactor Regul Iat]ion U. S. Nuclear Regulatory Commission Mail Stop 7E1 Washington, DC 20555-2738 Missouri Public Service Commission Governor OfficeffBiklling 200 Madison Street P0 Box 360 Jefferson City, ýMO 65 102-0360

ULNRC-05385 March 26, 2007 Page 4 of 4 bcc: D. T. Fitzgerald (w/o)

G. A. Hughes (w/a)

• D.E. Shafer (w/a) (470) (2 copies)

S. L. Gall agh er (w/o) (100)

S. L. Kiang (w/a) (NSR.B)

K. A. Mills (w/a)

D. M. Stepanovic (w/a)

M. G. Hoehn 11 (w/a)

D. J. Maxwell (w/a)

S. L. McCracken (w/a)

T. B. Elwood (w/a)

A160.0761 Chrono file The following are each provided a copy without attachments:

Ms. Diane Hooper Mr. Rodney Wilferd Supervisor, Licensing STARS RASIG WCNOC Proj ects Manager P.O. Box 411 P.O. Box 52034 Burlington, KS 66839 Mail Station 7636 Phoenix, AZ 85072-2034 Mr. Scott Bauer Mr. Dennis Buschhaurn Regulatory Affa IrS Comanche Peak SES Palo Verde NGS P.O. Box 1002 P.O. Box 52034, Glen Rose, TX 76043 Mail Station 7636 Phoenix, AZ 85072-2034 Mr. Scott Head Mr. Stan Ketelsen Supervisor, Licensing Manager, Regulatory Services South Texas Project NOC Pacific Gas & Electric MailI Code N5014 Mail Stop 104/5/536 P.O. Box 289 P.O. Box 56 Wadsworth, TX 77483 Avila Beach, CA 93424 Mr. John O'Neill Certrec Corporation Shaw, Pittman 4200 South Hulen, Suite 630 23)00 N. Street N. W. Fort Worth, TX 76109 Washington, DC 20037

Attachment I to ULNRC-05385 Page 1 of 7 Responses to NRC RAI Questions (and Correction of Information) Regarding 10 CFR 50.55a(a)(3)(i) Request for Planned Installation of Full Structural Weld Overlavs for Pressurizer Nozzle Welds Reference 1: AmnerenUE letter ULNRC-05292, "Request for Relief From ASN4E Section XI Repair and Replacement Requirements: Proposed Alternatives for Application of Structural Weld Overlays to Pressurizer Nozzle Welds," dated 14 August 2006.

The following provides AmerenUE's responses to questions identified by the NRC staff from their review of the 10 CFR 50.55a(a)(3)(i) request (i.e., relief request) submitted by AmerenUlE per Reference 1. The Subject relief request is intended to support the installation of full structural weld overlays for the pressurizer nozzle welds at Callaway Plant. The weld overlays are a planned mitigation activity to address concerns associated with dissimilar metal welds potentially Subject to primary water stress corrosion cracking (PWSCC).

The NRC questions addressed as follows were electronically transmitted to ArnerenUE inl October 2006. During a telephone di scussi on of AmnerenUE' s preliminary/draft responses to the NRC's RAJ. questions in February, additional comments/questions were provided at that time. All questions/commlents received constitute the NRC's request for additional information (RAT) pertaining to the subject relief request. Each RAI question below (in italics) is followed by AmerenUE's response to the question. Some questions are Subdivided Such that each part is separately addressed.

In addition to the responses provided for the NRC's RAT questions, some corrections to the relief request (provided as Attachmient 1 to IJLNRC-05292) have been identified.

These are provided after the responses to the RAI questions belowv (i.e., at the end of this attachment).

1) S5pecifj' the inservlice inspection (1Sf) interval and the begin/end datesfor the interv~al.

Response: The weld overlays will be Installed during Callaway Plant's third 1 0-Year ISI interval which began on December 19, 2004 and ends on December 18, 2014.

2a) Undcer Section 3.2 of the attachinent to the submnittal dated August 14, 2006, it is stated that the conditions imiposed on N-638-] ais given in Regulatory Guide (RG,) 1.147, Rev~ision 14, are not applicablefor the intended application. Identify the ultrasonic testing (UT) acceptance criteriatthat will be used for the comiplete full structural weld overlay (FSWOL) and heat affected zone beneath the weld ov~erlay. If the acceptance

Attachment I to ULNRC-05385 Page 2 of 7 criteria to be used are not consistent with the respective positions stated in RG 1. 147 for the applicable Code C'ases, provide the technical basesfor their use.

Response: The volUmnetric acceptance criteria for the required structural overlay weld metal and the outer 25% of the base metal Volume below the structural overlay weld metal will be per Nonmnanclatory Appendix Q, Q 41 00(c). The required structural portion of the weld overlay is defined in the pre-emptive FSWO.L design drawings.

2b) Address technically why it is appropriateto comiply; wit/h the condition in N-504-2 versus the condition in N-638-1. Also, address whether PSI!PT acceptance criteria are going to be based on the Construction Code.

Response: Both Code Case N-504-2 and Nonmnandatory Appendix Q apply specifically to repair by weld overlay. In contrast, Code Case N-63 8-1 applies to excavation to reduce a defect to an acceptable size and the subsequent repair by welding.

Because Code Case N-638-1 applies specifically to excavation to reduce a defect to an acceptable size, whereas Callaway is applying a weld overlay, Code Case N-638-1 is not appropriate. However, because Callaway will be applying a weld overlay, application of weld overlay specific Nonmnandatory Appendix Q is appropriate for Callaway and provides the appropriate technical inspection requiiirements.

In summary, Callaway Will use the weld overlay specific Nonmandatory Appendix Q for the voIlumetric acceptance criteria for the required Structural weld overlay weld metal and Outer 25% of the base metal voIlum1e. Specifically, Callaway will apply Q-4100(c) of Nonmiandatory Appendix Q.

The PSI acceptance criteria will be performed in accordance with Q-4200 of Nonmandatory Appendix Q.

3) Provide a regulatory connmitmnent to submnit, within 14 days froin comipletion of the UT examfination of tihe weld overlays, a report that snunmarizes the results of the examninations, consistent with the Septeinber 14, 2006 letterfr-oi Exelon to NRC regardingByron Station, Unit .1 Relief Request 13R-03.

Response: As noted in the cover latter and as identified in Attachment 2, a summary report of UT results will be Submitted to the NRC staff 14 days after completion of final UT examinations performed to the requirements of PD] UT-8.

4) Discuss your intentions with respect to the analyses requiredunder N-504-2 (g,)(2,)

amid (g,)( 3,) with respect to plant startup. ft is the NRC staffs intention that these analyses be conducted prior to placing the subject welds in service.

Attachment I to ULNIRC-05385 Page 3 of 7 Response: The analyses required under N-504-2 (g)( 2 ) and (g)( 3 ) will be conducted prior to placing the subject welds in service.

5a) Discuss your plans regarding,the comnpletion of the 1ST7area UT of the overlay under N-638-1.

,Final UT examination will include examination Of the Structural overlay weld metal and the Outer 25% of the base metal volume below the structural overlay weld metal. The UT examnination will not include base metal at 1ST distance beyond the overlay weld as specified in N-638-1. A PT Surface examination will be perform-ed V2 in1. from each side of the overlay weld per Nonmandatory Appendix Q, Q-41 00(b).

5b) The 1.5T area is a requiremnen~t that the licensee is required to mneet tinder N-63 8-I.

Withi respect to the licensee 's proposedalternative, the licef isee nieeds to ask for relief and provide ci technical bcasis ais to wvhy'1 the proposed alternativeprovides aii acceptable lev~el of qua~lity anidsa-fety;. Neither the suibmittal nor the licensee 's prelimfinary;RAI response demionstrates wýihY 10 CFR SO.55a('a,)(3,)(1,) or (3,1(ii) is mnet.

Response: The following in formation fromn Cal laway Plant Relief Request, document ULNRC-05292, Table 3, "Modifications to Code Case N-638-1," with corrections identifie beow ioffered to fuirther demonstrate the acceptability of not performing the UT exam-inations of the felritic nozzle material band around the area to be welded of at least 1.5 times the component thickness or 5", which ever is less. For additional Technical Basis to Table 3, reference ASN4E approved Code Case N-638-3 and EPRI Technical Report 1003616, "Additional Evaluations to Expand Repair Limits for Pressure Vessels and Nozzles."

Examination of a band width 1.5 times the component thickness or 5 in., which ever i.s less, around the repair area after 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> at ambient temperature is for detection of delayed HAZ cracking that may Occur due to inadvertent introduction of deleterious monatomic hydrogen into a hardened base metal HAZ rnicrostructure that was not adequately tempered. The ferritic nozzle base material HAZ of thle first Alloy 52M layer is the only region susceptible to potential hydrogen delayed cracking. The volume and area requiring examination by Code Case N-504-2 and Appendix Q are therefore adequate for detection of hydrogen delayed cracking that occurs in vicinity of the First layer HAZ, and the excessive examination band region specified by Paragraph 4.0(b) is not necessary.

Hydrogen contamiination to deleterious levels fromn Outside Sources ISunlikely when applying the ambient temperature ternperbead mnachine GTAW process with thle associated methodologies speci fled for welding control, cleanliness, and examination. As compared to flux-type welding processes, machine GTAW with argon shielding is an inherently low-hydrogen process that provides optimlum temperbead welding controls to ensure adequately temnpered base metal HAZ with

Attachment 1 to ULNRC-05385 Page 4 of 7 high fracture toughness. The low hydrogeni and tempering characteristics of the machine GTAW process are well documented in EPRI GC-1 11050, "Ambient Temperature Preheat for fyiach inc GTA W Temperbead Applications."

Code Case N-504-2 and Appendix Q require liquid penetrant examination (PT) prior to installationi of the FSWOL. Cleaning the base metal for PT provides assurance, iMaddition- to typical welding process controls, that deleterious hydrogen from Surface contamination is not Introduced rinthe first layer of the FSWOL.

The high affinity of fuilly aulStenitic Alloy 52M filler metal for monatomic hydrogen combined with a low diffusion coefficient keeps diffusionl of deleterious hydrogen into the low alloy ferritic base material to negligible levels. Furthermore, only welding in contact with the low alloy ferritic base material has potential of introducing deleterious moniatomnic hydrogen into a hardened untempered HAZ region. Each successive temperbead layer has a decreasing propensity for introducing hydrogen into the ferritic base material due to ]Increasing distance from the Susceptible base metal HAZ. After three layers the temiperbead process adequately tempers the martenisite formed in the ferritic base material by the first layer. Adequate tempering by the third weld layer decreases the hardness and increases the fracture toughness in the potentially Susceptible ferritic base material

.HAZ thus mitigating Susceptibility to delayed hydrogeni cracking.

Additionally, the initerpass temperature controls of Code Case N-63)8-1 maintain the temperature near or at ambienit temperature betweeni the relatively short and infrequent localized welding heat cycles. N-638-1 requires a 350'F interpass temperature for the first three layers to ensure adequately high cooling rates to promote a base mi-etal [-AZ microstructure with high fracture toughness. A 350'F initerpass temperature is required for the fourth and Subsequent layers to protect against sensitization of the auisteniitic groove weld and austenitic base materials and to maintain an acceptable mnicrostructure ini the Alloy 52M overlay weld metal. The 350OF interpass temperature controls maintain the ferritic base metal HAZ at relatively low temperatures, which effectively contributes to time at or near ambient temperature. For time during the welding process where temiperatures are above ambient, the elevated temperatures are beneficial and enhance diffusion of hydrogen out of the ferritic base material HAZ. It is therefore, both reasonable and conservative, to include the teirperbead welding time following completion of the third layer in the total 48-h1our hold time required prior to performing final examiniation- of the feiritic base material and of the FSWOL on the fenritic base material.

InI Summary, the inherent low hydrogeni nature of the prescribed ambient temperature temperbead mnachine GTAW process and methodology, the relatively low Susceptibility of hydrogeni induced cracking in ferritic base material HAZ when using nickel alloy filler metals, and performance of the Appendix Q and N-504-2 final examination- (as modified) 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 over the

Attachment I to ULNRC-05 385 Page 5 of 7 ferritic base material provides substantial assurance against the potential for delayed hydrogen cracking in the ferritic base mnaterial HAZ.

Additionally, ASME published Code Case N-638-3, which does not requnire examination of the band around the repair area, InI Supplement 9 to the 2004 Edition of ASME Section X1.

Therefore, based upon the technical information provided above, as taken from Table 3 of the Callaway Relief Request (with the corrections identified below) and the referenced EPRI Technical Report 1003616, final UT examination will Include examination of the structural overlay weld metal and the outer 25% of the base metal volume below the structural overlay weld mretal. The UT examination will not include base metal at 1.5T distance beyond the overlay weld as specified in N-638-1. This modification from N-638-1, is part of the overall approach that constitutes the proposed alternative to the Code requirements as described in Reference 1.

6) The staff has not previously granted relieffor the 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />sfrom ambibent timiefor (lie commencement of non-destructive examination ('NDE,) after the overla); to anly licensee.

Therefore, the licensee is requested to modify5 the reliefrequest accordingly. This issue remains open, however, until afterfurther discussions betwveen NRC and ASME staff anld/or submnittal of the applicableEPRI document addressing this provision.

Response: EPRI Report 1013558, "48-Hour Hold Requirement for Ambient Temperature Temperbead Welding", which is in the possession of the NRC staff, provides Justification for deviation from the 48-h1our hold requirements of Code Case N-638-1. This document has been evaluated by the Callaway staff, and it has been deemned applicable for installation of the preemptive full Structural weld overlays at Callaway. An additional copy of the EPRI report can be submitted if needed.

7) In your submittal dated August 14, 2006, it is indicated that the overlay (s,) may be up to 500 sq. in. and later Code Cases, not approved in R G 1. 14 7, are quoted as the basis.

The NRC staff has approved up t~o 300 sq. in. Provide the estinmated actual surface areas on the ferritic miiaterials and why the configuration is similar to those previously approved by the staff. Areas in excess of 300 sq. in. will require a plant-specific stress analysis and supporting argument.

Response: Weld overlays will not exceed 300 sq. in. surface area on the ferritic nozzle base material.

The NRC acceptance of previously approved relief from the 100 square-inches limitation tip to and Including 300 square inches was based upon industry leading work demonstrating acceptable larger areas of ambient temperature temper bead welding. That industry leading work, reported in EPRI Technical Report 1003616, "Additional Evaluations to Expand Repair Limits for Pressure Vessels and Nozzles" and the ASME approved Code Case N-638-3, increased the 100 square-inch limitation to 500 square

Attachment I to ULNRC-05385 Page 6 of 7 inches, and the technical basis accompanying those documenC1ts provides an expanded basis For the change in limritation.

Iii addition to [EPRI Technical Report 1003616 aiid ASME Code Case N-638-3, Wolf Creek applied Structural weld overlays with limitations in excess of 100 squlare inches.

Both Callaway aiid Wolf Creek are SNIJPPS designs, (lemronstrating the simrillarities between Wolf Creek and Cal laway.

To ensure the expanded surface area of limitation provides an acceptable level of quality and safety, a final NDE of the weld overlay will be performed, detecting any cracking that may occur.

In Summary, based upon the referenced EPRI Technical Report 1003616 and ASME Approved Code Case N-638-3, weld overlays will not exceed 300 square inches Surface area on the ferritic nozzle base m-aterial.

8a) Discuss the r-epairstr-ategy if the PWOL PSI NDE reveals indications that exiceed the acceptance criteria stated under-App en dix Q of the ASME Code,Section XI.

Response: PSI ultrasonic indications characterized as weld flaws in the overlay weld metal that exceed the acceptance stanidards of IWB-35 14-2 shall be removed or reduced to an acceptable size. Indications located in the outer 25% of the base metal that are characterized as cracks must meet the design analysis requirements as specified inl Nonniandatory Appendix Q, Q-3000.

8b) Address PSI PT and ivhat acceptance criter-ia wtill be used.

All NDE wvill be performed V/2 inch from each side o~fthe overlay weld in accordance with Nonmandatory Appendix Q, Q-4100. The PSI acceptance criteria to be applied will be in accordance with Nonimandatory Appendix Q, Q-4200. (See response to RAI Question 2b.)

Attachment I to UJLNRC-05385 Page 7 of 7 Corrections to Relief Request Table 3 The following are corrections to text/inform-ation that was provided in Table 3 of the relief request (Attachment 1 to ULN-RC-05292)...

Table 3 Correction (Paue 14 of 31:. I" section: 2 "(1column111; last paragraph)

Code Case N-638-1 requires 35O-k--OW'F interpass, temperature for the first three temiperbead layers and 3-z54'F intcrpavss temperature for all Subsequent layers. The 350-l-5-00 F interpass on the first three layers provides adequate control to ensure tempered martensite with adequate tou~ghness in the low alloy fer-ritic nozzle material, and the 350'F interpass for all Subsequent layers ensures the SS weld and base material are not sensitized. The interpass temperature controls of N-638-1 are therefore adequate to ensure acceptable mechanical properties and structural integrity of the overlay weldment.

Table 3 Correction (Paae I. of3l; J."section; 2 "'1columrn; 1 st ~ar-aaraph)

Additionally, the interpass temperature controls of Code Case N-638-1 maintain the temperature near or at amrbient temperature between the relatively short and infrequent localized welding heat cycles. N-638-1 requires a 3504-50".1 interpass temperature for the first three layers to ensure adequately high cooling rates to promote a base metal HAZ m'licrostructure with high fr-acture toughness. The 350'F interpass temperature Is required for the fourth and Subsequent layers to protect against sensitization of the austenitic groove weld and austenitic base materials and to maintain an acceptable microstructuire in the Alloy 52M' overlay weld metal. The -l--5-0~f'-.a*-350'F interpass temperature controls maintain the ferritic base metal HAZ at relatively low temperatures, which effectively contributes to time at or near ambient temperature. For timre during the welding process where temperatures are above ambient, the elevated temperatures are beneficial and enhiance dliffusion of hydrogen out of the ferritic base material HAL. It is therefore, both reasonable and conservative, to include the terrperbead welding time following completion of the third layer in the total 48-hour hold time required prior to performning final examination of the ferritic base material and of the FSWOL on the ferritic base mi-aterial.

Attachment 2 to ULNRC-05385 Page I of 1 LIST OF COMMVITMENTS The followingc. table idenitiFies actions committed to by AmnereiU.E iii- this document (letter anid/or Attachment 1). Any other statements in this document are provided for iniformationl purposes aiid are not considered commitments. Please direct questions regarding this commitment to David E. Shafer, Superintendent, Licenisinig. at either 314-554-3 104 or 573-676-4722.

COMMITMENT Due Date/Event A summary report of UT results will be Submitted to the NRC Fourteen days after staff 14 days after comnpletion of final UT examinations performed completion of final to the requirements of PD[ UT-8. UT examinations performed to the requirements of PD]

UT 8 In Refuel 15.

Comipletioni of the analyses required under N-504-2 (g)(2) and Prior to placing the (g)(3)Subject welds in I service.