ML020910314

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Supplemental Information - NRC Bulletin 200-01, Circumferential Cracking of Reactor Vessel Head Penetration Nozzles Results of Metallurgical Investigation of Alloy 82/182 Cracking
ML020910314
Person / Time
Site: North Anna Dominion icon.png
Issue date: 03/22/2002
From: Hartz L
Virginia Electric & Power Co (VEPCO)
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
02-130, IEB-02-001, NL&OS/ETS R0 WCAP-15777
Download: ML020910314 (81)
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March 25, 2002 TO: NRC Document Control Desk Re: Vepco to NRC Letter dated 3/22/02; Serial No.02-130 Please be advised that the attachment to the above letter, "Metallurgical Investigation of Cracking of the Alloy 82/182 J-Groove Weld of the Reactor Vessel Head Penetration Joint at North Anna Unit 2 Station" (WCAP-15777) is NOT a proprietary document even though the document is marked as Westinghouse Proprietary Class 3. Westinghouse has advised us that this document is not proprietary and may be released to the public.

Maggie McClure Corporate Nuclear Licensing (804) 273-2200

VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 March 22, 2002 U.S. Nuclear Regulatory Commission Serial No.02-130 Attention: Document Control Desk NL&OS/ETS RO Washington, D.C. 20555 Docket No. 50-339 License No. NPF-7 Gentlemen:

VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNIT 2 SUPPLEMENTAL INFORMATION - NRC BULLETIN 2001-01 CIRCUMFERENTIAL CRACKING OF REACTOR VESSEL HEAD PENETRATION NOZZLES RESULTS OF METALLURGICAL INVESTIGATION OF ALLOY 821182 CRACKING In a letter dated January 11, 2002 (Serial No. 01-490E), Virginia Electric and Power Company (Dominion) provided the results of the reactor vessel head penetration nozzle inspections and associated repair activities for North Anna Unit 2. As part of the repair effort, a material sample was removed from penetration 62 for metallurgical examination by Westinghouse. WCAP-15777, "Metallurgical Investigation of Cracking of the Alloy 82/182 J-Groove Weld of the Reactor Vessel Head Penetration Joint at North Anna Unit 2 Station," contains the metallurgical results of the boat sample analysis taken from the North Anna 2 head during the Fall 2001 outage and is attached for your review.

If you have any questions or require additional information, please contact us.

Very truly yours, Leslie N. Hartz Vice President - Nuclear Engineering Attachment Commitments made in this letter: None

cc: U.S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth Street, SW Suite 23 T85 Atlanta, Georgia 30303-8931 Mr. M. J. Morgan (w/o attachment)

NRC Senior Resident Inspector North Anna Power Station Mr. J. E. Reasor, Jr. (w/o attachment)

Old Dominion Electric Cooperative Innsbrook Corporate Center, Suite 300 4201 Dominion Blvd.

Glen Allen, Virginia 23060

SN: 02-130 Docket No.: 50-339

Subject:

Supplemental Information - NRC Bulletin 01-01 COMMONWEALTH OF VIRGINIA )

)

COUNTY OF HENRICO )

The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by Leslie N. Hartz, who is Vice President - Nuclear Engineering, of Virginia Electric and Power Company. She has affirmed before me that she is duly authorized to execute and file the foregoing document in behalf of that Company, and that the statements in the document are true to the best of her knowledge and belief.

Acknowledged before me this 22nd day of March, 2002.

My Commission Expires: March 31, 2004.

Notary Public (SEAL)

Attachment WCAP-15777, "Metallurgical Investigation of Cracking of the Alloy 82/182 J-Groove Weld of the Reactor Vessel Head Penetration Joint at North Anna Unit 2 Station" Virginia Electric and Power Company (Dominion)

North Anna Unit 2

Westinghouse Proprietary Class 3 Metallurgical Investigation of Cracking of the Alloy 82/182 J-Groove Weld of the Reactor Vessel Head Penetration Joint at North Anna Unit 2 Station

,., Lo w "Alloy r/ Steel Sleeve .

Alloy 600 Penetration Tube .. Cadn+

Alloy 182 Buttering &

Location of Boat Sample i* \ Alloy 82 Attachment Weld

-- Guide Tube Funnel Westinghouse Electric Company LLC

WESTINGHOUSE PROPRIETARY CLASS 3 WCAP-15777 Metallurgical Investigation of Cracking of the Alloy 82/182 J-Groove Weld of the Reactor Vessel Head Penetration Joint at North Anna Unit 2 Station Summary of Findings of the Boat Sample Investigation Gutti V. Rao Westinghouse Materials Center of Excellence J. Bennetch Dominion Generation January 2002 Reviewer:

J. . Hail Component Integrity Approved: a.e Materials Center of Excellence This document is the property of and contains Proprietary Information owned by Westinghouse Electric Company LLC and/or its subcontractors and suppliers. It is transmitted to you in confidence and trust.

and you agree to treat this document in strict accordance with the terms and conditions of the agreement under which it was provided to you.

Westinghouse Electric Company LLC P.O. Box 355 Pittsburgh, PA 15230-0355 02002 Westinghouse Electric Company LLC All Rights Reserved 5842.doc-021902

iii TABLE OF CONTENTS LIST OFTABLES .......................................................................................................................................... iv LIST O F FIGURES ........................................................................................................................................ iv ACKNOW LEDGEM ENTS .......................................................................................................................... vii S INTRO DUCTION .............................................................................................................................. 1 2 EXAM IN ATIONS AND TESTS ................................................................................... ..................... 2 2.1 Surface exam inations ....................................................................................................... 2 2.2 Sectioning plan ............................................................................................................. 2 2.3 M etallographic exam inations ............................................................................................ 2 2.4 Fractographic Exam inations ........................................................................................... 2 2.5 Chem istry Evaluations ..................................................................................................... 2 3 RESULTS AND D ISCUSSION ................................................................................................... 4 4 M ECHAN ISTIC ASSESSM ENTS .............................................................................................. 7 5 CONCLUSIONS ................................................................................................................................ 9 6 LIST OF REFERENCES ................................................................................................................. 10 Appendix A Rotterdam Dockyard Company Manufacturing Drawings and Weld Procedures .......... A-1 Appendix B CRDM J-Groove Weld Procedures ............................................................................. B-1 WCAP- 15777 January 2002 5842.doc-021902

iv LIST OF TABLES Table 1 Summary of Chemistry Specifications for Alloy 182 and Alloy 82 Welding E lectrode and Filler M aterials ............................................................................................. 11 Table 2 Summary of Semi-Quantitative EDAX Chemistry Analysis Results of the Freshly Opened Fracture Face (Figure 23) (The results were corrected for oxygen peak) ........... 12 LIST OF FIGURES Figure 1(a) Photomacrographs illustrating Dye Penetrant Examination results of Penetration N o. 5 1 ........................................................................................................ 13 Figure 1(b) Photomacrographs illustrating Dye Penetrant Examination results of Penetration No. 62 (arrow indicates boat sample location) ............................................................. 14 Figure l(c) Photomacrographs illustrating Dye Penetrant Examination results of Penetration N o. 63 ......................................................................................................... 15 Figure 2 Schematic representation of the reactor vessel head penetration J-groove weld geometry illustrating the boat sample location at the low alloy steel to butter/clad in te rfac e ............................................................................................................................... 16 Figure 3(a) Surface Appearance of Boat EDM Face Showing the Presence of Axial and Transverse C racks (A rrow s) ........................................................................................... 17 Figure 3(b) Surface Appearance of Boat ID (Wetted) Face Illustrating the Presence of Grinding M arks and Cracks (Arrows) ........................................................................... 17 Figure 4 Appearance of Wide Crack (Figure 3a) on the EDM Surface of the Boat in the As-received C ondition .................................................................................................... 18 Figure 5 Close-up View of the Boat ID Surface Illustrating the Appearance of Transverse Cracking 19 Figure 6 Sectioning plan of the boat illustrating the identification of various specimens em ployed in the exam ination ......................................................................................... 20 Figure 7 Metallographic Examination results of the transverse section of the boat identifying the cracking locations. (M245 1) Details at areas E, F. G and H are illustrated by the higher Magnification micrographs in Figures 9 through 14.................................... 21 WCAP- 15777 5842.doc-021902 January 2002

V LIST OF FIGURES (Cont'd)

Figure 8 Metallographic Examination results of the transverse section of the boat illustrating the distribution of cracking. Arrows indicate locations of crack extension to the I.D . w etted surface of the boat .......................................................................................

22 Figure 9 Metallographic Examination results of the transverse section (M245 1) of the boat in the 'as-polished' condition illustrating the crackingmorphology at Area 'H', Figure 7... 23 Figure 10 Metallographic Examination results of the transverse section of the boat identifying the cracking locations. (Area 'F' in Figure 7) .............................................................

24 Figure 11 Metallographic Examination results of the transverse section of the boat identifying the cracking locations. ...................................................................................................

25 Figure 12 Metallographic Examination results of the transverse section of the boat in the polished and etched condition identifying the cracking locations in the polished and etched condition. (N ital etch) ......................................................................................

26 Figure 13 Metallographic Examination results of the transverse section of the boat identifying the cracking locations in the polished and etched condition. (Nital etch) ...................

27 Figure 14 Metallographic Examination results of the transverse section of the boat identifying the cracking locations in the polished and etched condition. (Area 'H' in Figure 7)

Nital etc h............................................................................................................................. 2 8 Figure 15 Metallographic Examination results of an axial section (M2452, Figure 6) of the boat illustrating the cracking morphology. (Nital etch) ......................................................

29 Figure 16 Montage of SEM Fractographs of the freshly opened crack through the boat illustrating inter-dendritic and fracture morphology. Refer to Figures 17 & 18 for details at areas A ,B and C .............................................................................................

3 0 Figure 17 Oxide covered dendritic morphology of the fracture face (Figure 15) ..........................

31 Figure 18 Overload dimpled fracture morphology seen in the boat corner .......................

32 Figure 19 Elemental mapping of approximate quantitative EDAX chemistry analysis results of the transverse section. M2451 (The white arrows identify the locations of spot analysis) .................................................................... ...................... . 33 Figure 20 Summary of Energy Dispersive X-ray Chemistry Analysis results of the transverse section illustrating the location of the butter and weld regions. (M2451) ...................

34 WCAP- 15777 W4.CAP-2157 5842.doc 021902 January 2002

vi LIST OF FIGURES (Cont'd)

Figure 21 Energy dispersive x-ray results of the axial section illustrating the location of a crack in the butter material. (M2452). White arrows identify the locations of spot a n a ly sis ................................................................................................................................ 35 Figure 22 Typical EDAX Spectrums Taken from the Freshly Opened (Wide Crack) Fracture Face (See Table No. 2 for semi-quantitative analysis results) ...................................... 36 Figure 23 Summary of Auger Electron Spectroscopy (AES) results of the freshly opened fracture face. (mating face to the right bottom fracture region in Figure 16) .............. 37 Figure 24 Auger Electron Spectrum (AES) of interdendritic fracture face near the dimpled fractu re at ID ....................................................................................................................... 38 Figure 25 Auger Electron Spectrum (AES) of the fracture region away from ID ......................... 39 15777 January 2002 WCAP- 15777 January 2002 5842.doc-021902

vii ACKNOWLEDGEMENTS The authors wish to acknowledge the assistance of R. A. Reese and C. M. McGuire of Westinghouse in conducting hot cell examinations. The assistance of A. Byers in conducting Auger analysis is appreciated.

J. A. Hoffman was helpful in co-ordinating the illustrations in the report.

The authors further acknowledge the following personnel who took time to review the draft report and provided helpful comments.

Robert Gold (Westinghouse)

Robert Phillips (TVA)

Greg Gerzen (Exelon)

Bob Hardies (BG&E)

Les Spain (Dominion)

Warren Bamford (Westinghouse)

John F. Hall (Westinghouse)

WCAP-15777 5842.doc-021902 January 2002

1 INTRODUCTION In October 2001, while conducting Generic Bulletin 2001-01 visual inspections of the reactor vessel head top surface, Dominion inspectors observed evidence of small boric acid deposits near the CRDM penetration numbers 51, 62 and 63 at North Anna Unit 2 Station. In order to disposition these three penetrations, non-destructive examination (NDE) of the J-groove partial penetration welds on the inside diameter surface of the vessel head were performed. The NDE inspections conducted by Westinghouse revealed reportable dye penetrant (PT) indications in the J-groove weld near the cladding interface of the three penetrations. In addition, surface etching was also performed on the attachment weld/butter/

cladding transition region of Penetration 62 to assess the width of the buttering layer and the relative position of the reportable indications. The results showed that the width of the buttering ranged from approximately 0.5 in. to 0.75 in. which is wider than the specified (6 mm or 0.24 in.) minimum width (see Appendix A and B). The PT examination results of the Penetrations 51, 62 and 63 are illustrated in Figure 1. In order to carry out a detailed metallurgical investigation, a 'boat' sample was removed from penetration no. 62 by Electric Discharge Machining (EDM) and shipped to Westinghouse hot cell facilities for analysis. The 'boat' sample was positioned circumferentially along the weld clad interface region and contained reportable PT indications on the uphill side but away from the previously etched region, for metallurgical investigation. Figures 1(b) and 2 illustrate the location of the boat sample relative to the penetration attachment weld, butter and clad positions. The PT indications captured in the boat sample were representative of these indications observed in penetration nos. 51 and 63. This report summarizes the findings of the hot cell examination of the boat sample from the penetration no. 62 J-groove weld.

WL4AI"-IM1112 January 2002

2 2 EXAMINATIONS AND TESTS The Westinghouse evaluations were centered on an approximately 2.5 inch long, 0.5 inch wide and 0.4 inch deep 'boat' sample oriented circumferentially along the weld-clad interface and removed by electric discharge machining (EDM) from the 'butter' region of the J-groove weld. The investigation included the following major tasks:

2.1 SURFACE EXAMINATIONS Surface examination of the boat sample were conducted in the as-received condition by light optical and scanning electron microscopy techniques for evidence of cracking, surface deposits, corrosion, pitting or mechanical distress. The results of the surface examinations are illustrated in Figures 3 through 5. The results are discussed in Section 3.

2.2 SECTIONING PLAN Based on the results of the surface examinations, a plan for destructive examination of the boat was developed. Figure 6 illustrates the sectioning lay out of the boat to obtain specimens employed in various examinations conducted during the investigation.

2.3 METALLOGRAPHIC EXAMINATIONS Metallographic examinations were conducted on axial and transverse sections of the boat sample by employing light optical and scanning electron microscopy techniques. The purpose of the metallographic examinations was to establish the depth and distribution of cracking, crack initiation locations and propagation directions, the cracking morphology and its relation to the local microstructure. The metallographic examinations were carried out both in the 'as-polished' and

'polished and etched' condition of the sections. The results of the metallographic examinations are illustrated in Figures 7 through 15. The results are discussed in Section 3.

2.4 FRACTOGRAPHIC EXAMINATIONS Fractographic examinations were conducted on freshly opened cracks in the boat by light optical and scanning electron microscopy techniques to establish the origin and depth of cracking, the fracture morphology, and the mechanism of crack progression. The results of the fractographic examinations are illustrated in Figures 16 through 18.

2.5 CHEMISTRY EVALUATIONS Chemistry evaluations were conducted by quantitative Energy Dispersive X-ray analysis (EDAX) technique by spot elemental analysis. The EDAX analysis was conducted at various locations of the polished boat sections to establish Alloy 82 weld, Alloy 182 butter, low alloy steel base metal, and stainless steel clad regions in the boat and further to identify the crack initiation and crack progression locations in relation to the buttering and filler metal regions of the J-groove weld. The results are illustrated in Figures 19 through 22.

WCAPJanuary 2002 5842.doc-021902

3 Limited thin film surface chemistry analysis of the freshly opened fracture faces was conducted by Auger Electron Spectroscopy (AES) to establish surface chemistry, identify the presence of boron from primary water and establish the presence of any low melting and/or detrimental elements present, to aid in the mechanistic assessments. Locations analysed are illustrated in Figure 23. The results are illustrated in Figures 24 and 25.

WCAP- 15777 January 2002 J04/.UUC-UL V VUL

4 3 RESULTS AND DISCUSSION The results of the surface examination of the boat sample in the as-received condition are illustrated in Figures 3 through 5. The surface examination resulted in several significant findings. First the boat contained several transverse and longitudinal (axial) cracks which were open on the 'back side' (EDM surface) 1 . Some of these cracks seemed to have narrowed as they approached the ID surface and appeared as tight cracks on the ID surface while several other cracks did not extend to the ID surface.

The ID face contained surface grinding and machining marks, presumably representing the original fabrication condition of the weld. No evidence of surface attack, deposits or pitting was seen on the surfaces exposed to primary water. The cracks observed at the surface likely started in the internal region of hot cracking, extending to the surface over several cycles of operation.

The results of the metallographic examinations conducted on sections taken both transverse and longitudinal (axial) to the boat are illustrated in Figures 6 through 14. The metallography results of the transverse section illustrated in Figures 7 through 14 revealed that the weld metal suffered significant cracking close to the base metal interface in the buttering layer of the J-weld away from the ID surface.

The cracking followed interdendritic morphology with significant evidence of interconnected microfissuring and voids. Although the transverse cracking appeared concentrated in the butter close to the EDM face near the base metal, as illustrated in Figure 8, in a few instances narrow, isolated single cracks extended into the boat (ID) face. Figure 15 illustrates the metallography results of an axial section of the boat. The presence of an axial crack progressing from the EDM face towards the ID face can be seen. The axial cracking is interdendritic, branched and followed serrated morphology. A clear distinction can be made between the behavior of this axial crack (near the ID wetted surface) and the cracking seen (near EDM face) on the transverse section (Figure 9). A discussion of the mechanistic assessments of the cracks seen in the transverse and longitudinal (axial) sections is included later in Section 4.

The fractographic examination results of a freshly opened crack are illustrated in Figures 16, 17 and 18.

Figure 16 is a montage of scanning electron fractographs illustrating the fracture morphology of a transverse crack through the thickness of the boat. The cracking morphology of selected areas of the fracture is shown at higher magnification in Figure 17. The fractographs illustrates oxide covered interdendritic morphology. Presence of interdendritic gaps and occasional voids are also apparent. The morphology of laboratory induced overload dimpled rupture is illustrated in Figure 18.

The results of the semi-quantitative chemical analyses by Energy Dispersive X-ray (EDAX) technique tend to confirm the fractographic conclusions. EDAX chemistry analyses of a freshly opened fracture face are illustrated in Figure 22 and in Table 2. The elemental spectrum from the fracture clearly shows a significant oxygen peak indicating that the cracking occurred at elevated temperature during fabrication, a condition that is favorable to oxidation of the fracture face. Because of the presence of the significant oxygen peak the semi-quantitative results of the chemistry in Table 2 should be considered approximate.

' The transverse boat cracks were actually circumferential flaws with respect to the J-groove weld whereas the longitutinal (axial) boat cracks were radial weld flaws.

WCAP- 15777 January 2002 WCAP- 15777 January 2002 5842.doc-021902

5 In addition, the results indicate that the fracture occurred in the Alloy 182 butter material. The Rotterdam chemistry specification requirements of Alloy 182 buttering and Alloy 82 weld deposit are provided in Table 1 for reference.

As shown, the EDAX results also confirm that the boat sample was machined primarily from the butter region. Elemental EDAX values are shown in Figure 19 for the transverse section, in Figure 21 for the axial section. No evidence of stainless steel cladding (at the ID face) or low alloy steel base material (at the top EDM face) was identified in the boat sample. Only a portion of the top region of the boat (Figure 20) contained Alloy 82 weld deposit (see Figures 20 & 21). Note that virtually all cracking seen here was confined to the Alloy 182 butter layer. Very little cracking was observed to extend into the Alloy 82 weld deposit.

The transverse section of the boat illustrated in Figure 20 showed that a portion of Alloy 82 weld deposit was trapped at the top of the boat bounded by Alloy 182 butter on either side. This configuration of the butter and weld materials is not normally expected and it is inconsistent with the specified weld fabrication procedures. This observation suggests that some type of a weld repair may have been involved at the buttering during the original fabrication of the weld. This is discussed further below.

The North Anna Unit 2 reactor vessel was fabricated by the Rotterdam Dockyard Company, Netherlands.

A detailed review of the vendor fabrication records was conducted to examine the weld procedures and any repair histories associated with the penetration 62 J-weld. The review could not identify penetration specific weld repair histories. However, general procedures employed in the repair of Alloy 182 buttering and Alloy 82 overlay weld deposits were identified. Copies of the original fabrication drawings and weld procedures including the general repair procedures of the weld are included under Appendices 'A: and 'B' of this report for reference.

There are potentially two postulated weld repair scenarios that can produce the weld configuration shown in Figure 20:

A weld repair involving cutting into the Alloy 182 butter layer at the Alloy 82 weld interface near the ID face and back filling with Alloy 82 weld metal.

An ID Alloy 82 weld repair at the butter interface employing an Alloy 182 electrode.

It may be of some interest to note that while the fabrication records (Appendix 'A') specified a minimum buttering width of 6 mm (0.24 in.), the entire boat width measuring approximately 0.5 in. consisted of Alloy 182 butter at the ID surface. This is also consistent with the surface etching results of the weld by Dominion during PT examinations (discussed in Section 1). The surface etching revealed that the width of the buttering layer ranged from 0.5 in. to 0.75 in.

The surface examination results of the boat sample in the as-received condition (Figures 3.b and 4.a) showed evidence of surface grinding and cold work on the wetted ID face.

The above sequence of observations suggests that a weld repair of the butter/weld region at the ID surface was most likely involved during fabrication of the penetration 62 J-weld. They also suggest that a surface grinding of the repaired region may have been conducted to disposition a recorded PT indication.

WCAP- 15777 January 2002 5842.doc-021902

6 The results of the surface chemistry analysis of a freshly opened fracture face by Auger Electron Spectroscopy (AES) is presented in Figures 23 through 25. The specimen employed (Figure 23) for AES analysis is taken from the bottom right corner of the mating face with the freshly opened fracture face illustrated in Figure 16. The AES analysis is a very useful technique in detecting the presence of low concentrations of detrimental elements on the surface such as grain boundary segregations or presence of low melting constituents so that their role in promoting embrittlement or failure can be assessed.

The technique analyzes an approximately 20 Angstrom (A) thick surface layer to establish the composition of a surface film on the fracture face. The results illustrated in electron energy spectra from the fracture face are summarized in Figures 24 and 25. Note the presence of boron, sulfur, zinc, copper and titanium at several locations of the fracture face including near the ID wetted face. In addition boron was detected at isolated locations on the fracture. It should be emphasized that the AES analysis effort made here was very limited, aimed only at giving a rough indication of the presence of detrimental elements. The results showed that the fracture surface contained several low melting constituents. Their significance is discussed in Section 4.

VCAP-15777 R42 do1rn fl9QnfJnur January 2002 5 20 84 ....... ... 0

7 4 MECHANISTIC ASSESSMENTS The results of the investigation showed that:

  • The entire ID face of the boat sample consisted of Alloy 182 butter material suggesting that the boat was located within the butter layer adjacent to the cladding.
  • The cracking observed in the boat was restricted to the Alloy 182 buttering. The majority of the crack population was situated near the EDM face, away from the ID surface exposeýt to the primary water. The cracking extended into (or connected to) a few isolated tight cracks at the ID face.
  • Two categories of cracks were identified, based on location and appearance. The majority of cracks fell into the first category. These cracks never extended to the ID wetted surface of the boat sample but were observed near the opposing EDM face away from the ID. They can be described as broad interconnected microfissures and cracks following adjacent parallel interdendritic paths, accompanied frequently by voids. This type of cracking substructure closely resembles 'Solidification Cracking' or 'Hot Cracking' generated to accommodate excessive strains or displacements induced during the solidification of the weld metal. The movement of supports (or interfaces) or thermal strains at bimetallic interfaces can induce excessive strains depending on the weld procedures followed. In addition, presence of low melting constituents in the weld metal can increase the solidification range beyond the critical solidification range and thus increases its susceptibility to hot cracking.
  • A second less frequent type of crack extended towards the ID wetted surface of the boat sample, apparently originating from some of the hot cracking seen near the EDM face (Figures 15 and 21). The latter cracks progressed along a single interdendritic path exhibiting a narrow tight branching and serrated morphology, as opposed to the appearance of the network of interconnected hot cracks. This morphology is consistent with the cracking behavior seen in Alloy 182 under exposure to primary water (Reference 1) which is commonly known as Primary Water Stress Corrosion Cracking (PWSCC). However, since not all of these narrow cracks extended to the ID surface, PWSCC did not appear to play a primary role in crack initiation and growth.

PWSCC likely contributed to crack growth once flaws broke the ID surface and became exposed to the PW environment.

0 There were at least two broad hot cracks found wide open at the rear EDM face that were connected to the ID wetted surface of the boat sample via narrow ID cracks. Fractographic examination of one crack face in a freshly opened condition at/near the ID surface showed evidence of heavily oxidized and widely separated dendrites (Figure 17). The presence of high temperature oxides indicated the crack had been open to the surface for an extended time period.

Auger Electron Spectroscopy of the fracture surface confirmed the presence of contaminants including zinc, sulfur, boron, copper and titanium (Figure 23). The evidence of boron, presumably from boric acid, seen in the AES spectra indicated the intrusion of primary water (PW). This observation backes up the conclusions reached by fractography that PWSCC played a secondary role in crack growth once cracks extended to the ID wetted surface of the weld. Sulfur and low melting point elements such as copper and zinc have been implicated in hot cracking in W4CAP- 15777 January 2002 5842.doc-021902

8 nickel-base alloys. Although the source of these elements needs to be further identified, their presence here suggest that the broad open cracks seen at the EDM face most likely occurred by a hot cracking mechanism during fabrication due to contamination of the butter weld. It is conceivable that the hot cracking was not detected at the time of fabrication because no cracks had yet extended out to the ID weld surface, resulting in no reportable linear indications. Then, during subsequent cycles of operation, ID cracks finally surfaced, only then introducing an environment conducive for PWSCC.

  • The hot cracking is seen extending through several passes of weld metal as it approached the ID (Figure 8). This is not considered an uncommon occurrence. Depending on the magnitude of strains developed during solidification, the stress (strain) concentration at the tip of initial crack in the proceeding weld layer provides a driving force for extension into the succeeding layer.

Another important contribution can come from the residual stresses from multiple repairs on the ID surface.

  • The observed cracking behavior of the buttering or weld in the North Anna boat is similar to the hot cracking reported in the penetration 62 J-weld buttering at Ringhals Unit 2 in 1992 (Reference 2). In the case of Ringhals 2, however, there was also decohesion (lack of fusion) observed at the base metal interface. The North Anna Unit 2 boat sample did not exhibit evidence of interface decohesion. However, the boat sample did not contain any base metal.
  • In summary,

- The large gaps or "open cracks" seen in the boat sample are the result of hot cracking in the Alloy 182 buttering deposit.

- The observation of (elevated temperature) oxides on the interdendritic surfaces indicate that, these regions were exposed to the air at solidification temperatures during fabrication.

- The hot cracks were not detected during manufacture and subsequent PT inspection since they apparently did not intersect the free surface at the weld stage where PTs were performed (The Rotterdam specification called for PTs every half inch after the first weld layer).

- There is very little evidence that cracking occurred in Alloy 82 - if at all, it appears that the open (hot) cracks may have been blunted when they reached the Alloy 82 weld region.

- Most of the cracking/degradation was the direct or indirect result of manufacturing.

PWSCC played a minor, secondary role.

The presence of grinding marks on the boat ID wetted surface plus the odd juxtaposition of 82 and 182 welds in the transverse and longitudinal metallographic boat sections suggest that repairs may have been performed on the J-groove weld during fabrication.

WCAP- 15777 January 2002 5842.doc-021902

9 5 CONCLUSIONS

  • The results of this investigation indicate that the cracking in the J-groove weld or buttering of the North Anna Unit 2 reactor vessel head penetration 62 most likely originated from solidification (hot) cracking of the buttering adjacent to the low alloy steel base metal. The results also showed that, once hot cracking extended to the ID surface, further crack extension most likely occurred by primary water stress corrosion cracking.

0 No significant cracking was detected in the Alloy 82 weld deposit.

  • No evidence of surface attack, deposits or pitting was seen on the wetted boat surface, implying that cracks did not originate at the weld surface. Rather, these cracks observed at the surface likely started internally in the region of hot cracking, extending to the surface over cycles of operation.

Hot cracking that extended to the ID facilitated the access of primary water and additional crack extension by PWSCC in the butter.

  • Repairs may have been made to the J-groove weld during fabrication.

Although it is plausible that the interconnected hot cracking and extension by PWSCC in the butter or weld layer could contribute to leakage through the head-to-penetration annulus, this could not be conclusively established based on the results of the current investigation.

The overall results of this investigation strongly suggested that the North Anna Unit 2 reactor vessel head penetration J-groove weld cracking originated from the original fabrication of the weld.

15777 WtJAJ- 15777 January 2002 W4AP- January 2002 5842.doc-021902

10 6 LIST OF REFERENCES

1. G V. Rao "Metallurgical Investigation of cracking in the Reactor Vessel Alpha Loop Hot Leg Nozzle to Pipe Weld at the V. C. Summer Station" Westinghouse non-proprietary class 3 report, WCAP- 15616, January 2001.
2. B. A. Bishop, G V. Rao, W. H. Bamford and S. L. Abbot " R V Closure Head Penetration Supplemental Assessment of NRC SER Issues" Westinghouse Proprietary Class 2 Report, WCAP-14219, Rev. 1, October 1995.

W(JAP- 15777 January 2002 5842.doc-021902

11 Table 1 Summary of Rotterdam Chemistry Specifications for Alloy 182 Welding Electrode (Butter) and and Alloy 82 Filler Note that the cited ASME sections have been discontinued.

Ni C Fe S Si Cu Ti P (Min.) (Max.) Mn (Max.) (Max.) (Max.) (Max.) Cr (Max.) Nb (Max.) Others Inconel 182 balance 0.11 5.0 -9.5 15.0 0.015 1.0 0.50 12.5-17.0 1.0 1.0-2.50 0.12 0.5 Electrode (max) Nb + Ta (max)

ASME SB-295 EMoCRFe-3 (SFA-5.1 1)

Inconel 82 balance 0.07 3.0-5.0 2.0-5.0 0.015 0.75 0.50 13.0- 17.0 1.0 2.0-3.0 0.1 1.0-2.5 Filler Rod Nb only Mo ASME SB-304 ERNiCR-3 (SFA-5.14)

Reference:

Rotterdam specifications (see appendix) v.rn1II D XX1IrA I r77-7 5842.doc-021902 January 2002

12 Table 2 Summary of Semi-Quantitative EDAX Chemistry Analysis Results of the Freshly Opened Fracture Face (Figure 22)

(The results were corrected for oxygen peak) The high Mn and Fe peaks show that the crack propogated in 182 weld Ni Mn Fe Si Cr Ti Nb Total Area 1 67.22 9.06 7.16 0.60 12.54 1.26 2.16 100.00 Figure 22(a)

Area 2 57.53 10.79 7.05 1.56 16.40 3.29 3.38 100.00 Figure 22(b)

WflAP- 1577-7 5842.doc-021902 January 2002

13 (i) (ii)

(iii) (iv)

Figure 1(a) Photomacrographs illustrating Dye Penetrant Examination results of Penetration No. 51 WCAP-15777 January 2002 5842,dc-021902

14 (i) (ii)

(iii)

Figure l(b) Photomacrographs illustrating Dye Penetrant Examination results of Penetration No. 62 (arrow indicates boat sample location)

January 2002 5842.doc-021902

15

A (i) (ii)

(iii) (iv)

Figure 1(c) Photomacrographs illustrating Dye Penetrant Examination results of Penetration No. 63 WCAP-15777 January 2002 5842 do,-021902

16 Low Alloy Steel Thermal EDM Face Sleeve Alloy 600 S.S. Cladding Penetration Tube

/

II Wetted i.D.

Alloy 182 Buttering Surface

& Location of Boat Sample Alloy 82 Guide Tube Funnel Figure 2 Schematic representation of the reactor vessel head penetration J-groove weld geometry illustrating the boat sample location at the low alloy steel to butter/clad interface. Note that the long transeverse axis of the boat is oriented parallel to the 182/S.S. cladding interface, whereas the short longitudinal axis is in the radial direction with respect to the J-groove weld WCAP-15777 5842.doc-021902 WCAP-5777January 2002 L Lf

17 Wide].Crack 10 mm I I I I r 5I 3 "'

cit Figure 3(a) Surface Appearance of Boat EDM Face Showing the Presence of Axial and Transverse Cracks (Arrows) Note that the long axis of the boat is oriented parallel to the Alloy 182 butter/stainless steel cladding interface "10 mm 04 6 7 8 9 1.

5 4 Figure 3(b) Surface Appearance of Boat ID (Wetted) Face Illustrating the Presence of Grinding Marks and Cracks (Arrows). Note that the long axis of the boat is oriented parallel to the Alloy 182 butter/stainless steel cladding interface WCAP-15777 5842.doc-021902 January 2002

18

  • , .*"
  • r' A e'.'2 * -.
  1. as 18 EDM SURFACE Figure 4 Appearance of Wide Crack (Figure 3a) on the EDM Surface of the Boat in the As-received Condition Alr n17 JI VO A.rD1 5842'.do--2 9III 5842.doc-021902 January 2002

19 I

11120,2001 (7 X)

(a)

(13X)

(b)

Figure 5 Close-up View of the Boat ID Surface Illustrating the Appearance of Transverse Cracking WCAP-15777 January 2002 5842 doc-021902

20

" 1B

"~i*PC.

PC. 2A  ! .. C A (M2451)P (M2452)

PC. 2B M ) PC. ID I

/

7 8 1 3 4 6 7 8 9 1 2 4 r v 6 1 2 34",

11/20/2001 Figure 6 Sectioning plan of the boat illustrating the identification of various specimens employed in the examination WCAP- 15777 5842.doc-021902 January 2002

21

.. EDM Cut Face Closerto.

,Low Alloy Steer Interface .,

" .. . . .. *d " . -A Opf to r-y Water'_3 s', .~-. 4>: *'."

S, .' Operto pnmasyWatr  :."4:

S. ~ ~ ~.*41;.CZ .... *;.

(5x)

(a) Polished Condition (reversed light)

(lOx)

(b) Polished and Etched Condition Figure 7 Metallographic Examination results of the transverse section of the boat identifying the cracking locations. (M2451) Details at areas E, F, G and H are illustrated by the higher Magnification micrographs in Figures 9 through 14.

WL-A'-I:I I//

January 2002 5842.doc-021902

22 EDM Face Z

(2X)

(I I.D. Wetted Surface Figure 8 Metallographic Examination results of the transverse section of the boat illustrating the distribution of cracking. Arrows indicate locations of crack extension to the I.D.

wetted surface of the boat. (Mirror image of Figure 7)

WCAP- 15777 January 2002 5842.doc-021902

23 0.010 in

-'qMM 1EDM Face z .

q S4 (a)

-J 0.005 in 4

10 (b)

Higher Magnification of (a)

Figure 9 Metallographic Examination results of the transverse section (M2451) of the boat in the 'as-polished' condition illustrating the cracking morphology at Area 'H', Figure 7.

WCA2- 15777 January 2002 5842.doc-021902

24 0.005 in A

.-A I

U, 7 p

  1. IF -. S.

0 A-AC

°* 2i 6

0.010 in EV

-I.

a 4

S vP 0 0

-I

.1

-PIP Figure 10 Metallographic Examination results of the transverse section of the boat identifying the cracking locations. (Area 'F' in Figure 7)

WL5A'-D19/ / /

January 2002

25 "4"C' 0.005 in

-N422f Area T-ir Area 'F' in Figure 7 0.010 In

-41 I

V

  • S

'V.. p Area 'G' in Figure 7 Figure 11 Metallographic Examination results of the transverse section of the boat identifying the cracking locations.

WCAP- 15777 5842.doc-021902 January 2002

26

-4'.

- 2' - -'-----

- -. - -ar A

-- A-,

-.- -1 Area 'H' in Figure 7 0.05 in

9. "'A-

. S"

., o -S-.

    • *-f, rr Area 'E' in Figure 7 Figure 12 Metallographic Examination results of the transverse section of the boat in the polished and etched condition identifying the cracking locations.

(Nital etch)

WCAP- 15777 5842.doc-021902 January 2002

27 S 0.020 in Area 'H' in Figure 7 S 0.005 in

-4w- - ,

SR4I~1rfl91Q0 Figure 13 Metallographic Examination results of the transverse section of the boat identifying the cracking locations in the polished and etched condition. (Nital etch)

"WCAP- 15777 January 2002 5842 doc-021902

28 28 I I ..- . .. . = -. -.. .- .*  ; .. - -.j **.. .

0.010 in - -

S- -" °. * ' .". .* * .*- - "/ -* , * ,' l

_-7

. ,*...,. ,..1G - ..

' ,- ./ * ** .**, i...-* . f -_ '* a"=*

.p-,- -.- * '* - . -... ,.

  • P--7 "e " .* - . .*- -. **.*,.  !.,,*: L (a) -,

4 1 1* " .--.- . '"-*lr-"

2' -  :,**"-*- , , . S.-

  • ...' - * .k° . .. . - ).* j~ - .-- " *- * .

Figure 14 Metallographic Examination results of the transverse section of the boat ietfing the cracking locations in the polished and etched condition. (Area 'H' in Figure 7,

Nital etch)

WCAP-15777 January 2002 5842.doc-02 1902

29 EDM surface

  • 1

-  ?'.}' :- -

If-,

'K.,

Figure 15 Metallographic Examination results of an axial section (M2452, Figure 6) of the boat illustrating the cracking morphology. (Nital etch)

WLAA'-IJ/ II January,.2002 January 2002 5842. doc-02 1902

30 30 EDM

/Face Overload Dimples Figure 16 Montage of SEM Fractographs of the freshly opened transverse crack through the boat, radial to the J-weld, illustrating inter-dendritic and fracture morphology. Refer to Figures 17 & 18 for details at areas A, B and C 11 T¢'* A VV.k- '- 15 / / January 2002 5842.doc-021902

31

  • ' £r,

- , :9A*' 'W * (350x)

Area 'A' in Figure 16 (20oX)

Area 'B' in Figure 16 Figure 17 Oxide covered dendritic morphology of the fracture face January 2002 WCAP- 15777 WCAP-15777 January 2002 5842.doc-021902

32 32 (560X)

Area 'C' in Figure 16 Figure 18 Overload dimpled fracture morphology seen in the boat corner Wr A D I IZ777 5842.doc-021902 January 2002

33 (12X)

Figure 19 Elemental mapping of approximate quantitative EDAX chemistry analysis results of the transverse section. M2451 (The white arrows identify the locations of spot analysis)

WCAP- 15777 January 2002 5842.doc-021902

34 (lox)

Figure 20 Summary of Energy Dispersive X-ray Chemistry Analysis results of the transverse section illustrating the location of the butter and weld regions. (M2451)

WCAP- 15777 5842.doc-02 1902 J n a y2 0

35 Figure 21 Energy dispersive x-ray results of the axial section illustrating the location of a crack in the butter material. (M2452). White arrows identify the locations of spot analysis.

WCAP-15777January 5842.doc-021902 2002

36 (a)

(b)

Figure 22 Typical EDAX Spectrums Taken from the Freshly Opened (Wide Crack) Fracture Face (See Table No. 2 for semi-quantitative analysis results). The square windows indicate the selected area for analysis.

WCAP- 15777 5842.doc-021902 January 2002

37 Intergranular Fracture:

Cu, Fe, Zn, S, Ti (after etch)

Intergranular Fracture:

Intergranular B, S, Zn Fracture:

Ca, Fe, Zn, S, Ti (after etch)

Intergranular fracture near ductile fracture: S I.D.

Surface Fracture Face (Inter-dendritic)

Fracture: Zn Figure 23 Summary of Auger Electron Spectroscopy (AES) results of the freshly opened fracture face. (Area 'C' in Figure 16)

X111rAfl'.,i~-iiI vvLPILr- I.j/ / /

.5842.doc-021902 January 2002

38 40097?,DAT Region 1 1 2 L1eQeel I Point 2 / o QV Region: r 5UR' EY 10 counts 27 mm from center of specimen, IGfailur k

.45 C

U 125

~115 105 200 400 600 800 1000 1200 1400 1500 Kinetic Energy /?

4009.,SDCAT Region ; 1 2LHy01 2 1/1 Point 2 2 eY Regions : IURYEY Lo Counts 27? mmfr cQnter of specimen, IGfailur Lo 600 pn O Zn u*0 n s 440 I I I I I I 60 80 100 120 140 160 180 200 Kinetic Energy ) Q'i Figure 24 Auger Electron Spectrum (AES) of interdendritic fracture face near the dimpled fracture at ID. (Area 'C' in Figure 16)

WCAP- 15777 January 2002 5842.doc-021902

39

ý0093SD,OA Region I1 2 LeOeY 1 ,' I Point I / I Fegions: SURVEY Lo Cut edge of spoc:men 2 min etch Counts F SURYEY C

00 U

t

60 400 600 Kinetic 800 S00 1000 En~ergy /' eVl 1200 1400 1600 0095', D.T Region 2 2 Le@e I I1 / Point I / I Regon: SURVEY 0V Lo Count:

edge of specimen 2 min etch 32"0 K300 C 280 0

n U 140 60 so 100 120 140 Kine*tic Energy i eV 180 200 Figure 25 Auger Electron Spectrum (AES) of the fracture region away from ID.

(Area 'C'in Figure 16)

WCAP-15777 5

842.doc-02 1902 January J n a y 2002 2 0

A-1 APPENDIX A ROTTERDAM DOCKYARD COMPANY MANUFACTURING DRAWINGS AND WELD PROCEDURES W.AP- 13 / /5/

5842-App.doc-02 1902 January 2002

A-2 IID Ll .

L IS

%I

  • _i .
  • I _ ' _. . . .

"JL " i-4Ii>..... -

'-App4 58 doc-2 190241

+. . . . . . _. .. .

'- @i--*

-@=-.-@ -f-- ._i_ ,(.

IbI L ._ @, ..: -_@ . .. ... @ , _

0. @ --. * /"

WCAP

[577.Jauary200 Figure A1I Reactor Vessel Closure Head Showing the CRDM Penetration Layout and J-Groov e Weld Geometry 5842-App.doc-021902 January 200-2

Zooz ýlunuuf Z061 zo-'x)pddV-Zt-gg LLL9 I -dV DAý IV ain2iA ul.,ff-ffU01PaSj0j!vla(j ZVoin2iji J-no nH 31MINAMIN *Giv VN *nw )100000VG 3H--$SWVGH3ilOS 3CI F-:-ý i v vgcý -. 99 0 q (03.1,C) ý, 'a.

0ý3. WDWWUd CERMWý.va'i cpw

,/s.j -. 91)oq " I "ON t4% QAHs)ljvsj -r'- A j VmOlwk Am3nogCenG U" I-Mw,ýM 3M %11COVIý Z

'"C 2)w 0j'sic svdwD cvj. .101

-flim 0

Ed

A-4 Z

~W

!:~l I II "

-I

~' H ~ . +I,,.IJJj~ I*r l, 1\1 ~=)le j\ U r S

1-+

- . . L, I

Figure A3 Reactor Vessel Closure Head Showing Penetration J-Groove Weld Joint WCAP 15777 .

January 2002 5842-App.doc-ON 902

rlj C) iu 35MMOEr.- -

Ld 9z dt oil r- C:?

B-I APPENDIX B CRDM J-GROOVE WELD PROCEDURES

1. Specification 37.02: Procedure for manual shielded metal arc weld overlay cladding with Inconel (F-Number 43) of low alloy steel (P-Number 12B).
2. Specification 34.06: Procedure for a combination of manual gas tungsten arc welding and manual shielded metal arc welding of solid Inconel (P-Number
43) to solid Inconel (P-Number 43) or to Inconel weld overlay cladding.
3. Specification 34.08: Procedure for a combination of manual gas tungsten arc welding and manual gas metal arc welding of solid Inconel (P-Number
43) to solid Inconel (P-Number 43) or to Inconel weld overlay cladding.
4. Specification 39.04: Procedure for repair welding in Inconel (P-Number 43) and Inconel weldments.

WCAP-15777 5 84 2

-App.doe-021902 January 2002

B-2 Speif,'-t Section Spec: !-,,I N'.:3 0 9

_________( 1')72- 2 P RO JEC fl D.M. O-&ý.- No.

e R-%;rz r.jer, SsuCJC  :?roceclre for n.~~1~~dirt~ r claddin.it witli Inc~onej ft~~ '5 of 1".."Lo steel (P-Ru'-r 12Dl),

I.

QuElif~icati 012o Qu;ýJific-atior date Spc' e. - rev, UNo,

'J"hn c Iz 1- -r;-s ý rnpe our_CI . (Ir.. m Par, 0!. 1.',-is~ -Ž

1. b-C' ?a:.:.ctaj I

VVl/l-ir-1J / [/

5842-App.doc-02 1902 JanUary 2002

B-3 Fn Za~ 72  :

tflt'1 A&LI ht' 14 t'!JiL la 3 '4.v - ~

!A'S'oiLfu~-V*.W~t~~.-6a..r~ u-~

0h

'T'1: 0:zt >2- .K; 0~Ia~7j2 2... C I'.'%

r-t+/-z

.2 -- . -.-

- - -. - ----. *--.-*----. -- .4.--

4.1 -T 1% - . 1 A3. r ~~f~  : T~J~ ,

4.).-

o: -n-1273 o ~0.1 1 -5 'Dnix Co 04 '1 aS 01ý ~ . I z1 ITU WCAP- 15777 5842-App.doc-02 1902 January 2002

B-4 9 4

- - ?A *~~o' a ~"' - C -~r~VVs~r "'~'

4 212 NK-M1 Imp. TiY~'v ~.

'4'C il D.>Tu

-q tp ýA t t 6~ ~ arb4igrs dr*~ atena z. til-n 6-71 Q-~a 400Ao II5 C-fic 7o A-,ie m-to taL, t-d AuvrcOi-tl cl~diný a4 t-%ipn c:,aird-g tilto' o waterals,a7or Thllat layertcjor iadzeltat eRange:15 1757 (I t.

i-ý In aocordaneit  ;'th l rqi cm.nts Uzi~ Z I t~

7isual3 aMb - - q-feetate WCP1777< January.Ine 2r002 fl 8r4cccodlttntig LlowdifrcrAre, Ath e-'

B-5 aft I sec 06.,.S popt- .:~*.2~~

F-8.1 6t'.

8.2~ifie o wldb~pzl to bc Co~i~n n ~ C,-3 L.7~

Acoor'~-oc ~c -u~rc7cic nee-,'e inX t-or p: c fice t end/rd..:i

'C No. 24.QG- P.nid in Ftdc'i-Ujon (0~ 77 cojre ~ijp~t )

by i~o OO~t~l-t .

12. rt Ac~rn~to in!ic'Un

-ýT) 3.

- te. o &.-

WCLAP-'-15177 5842 Appdix.-02 902January 2002

B -6 FLO.M. Order Hlo o -

IBV, w'Or Riferoncs:

sIM&Jct Prb64dure for a c'orubination of m-anual gas tuntatenx are ueolding end manual shieldel ipeta1 ard wrelding of E-olid Inconci (N-NITilibe~r 43) to solid trnconel (7-Murtber 45) or to Inconel weld overlay cladding.

'Qiif5.citor, No. K 541 K 565 ft~i~iicai~ond~te 70-05-01 70-00-05

-cv1V

- oe rpnjge qur1. (:)j-4.4 4.7-305 ____

70 "xX~j, 1%~

n 5842-App.doc-02 1902 January 2002

B-7

'Weldling of Incon.01 to Inconal (ASTO, SB-166, 167 or 168) eri Inconal 'weld overlay cladding in accordance with uic;.-,

of ASýME III and IX.

2. WeldinKF1,-t(rOuO..

No use of bac~king strip.

2.1 Yanmal st'm.rn.en arc weldlng7 (for first and last la~

String and/or weave travel.

Weaving widthi lim~ited to 3 mm.

vI~i~;iidth limited to 2 tiznc- electi~cda d 4 U,~r 3f Weld in!. no-it !inn.

3G (inc. o~f axis~ 300 + 150)..

4.1 lMr~lja c t~ntn arcw'1ll' F-Numiber 43: barc colid filler rod according to ASM7, SP-304 ER INiCr - 3 (SPA-5.14).

roci diamieter 1.0, 1.6, 2.0 and 2.4 Lwn.

shiclding gas : aran 099.99.

58VCApp b7-0197 January 2002

B-8 A.......iC Pt - (p...s.ji o cov~ed&Thtroe rini 7, eheiioalraige; C 0.07 % :.

Fe 3.0 - .0  %

OX 0.5 mw~ax.

C0.75 %max..

Ti 1. I Gr 13.0 - 17.0 5 Erb 2,0 - 3.c 5 M~O 1.0 - 2.

CO 0.1 5 s:

Ni bcrlaice

t. No_5._

flviane 15 -175DC.

7. Prenrr--atjon for weln.

.. In ft~o-vrcla with - 40rdnents of ASIO Ir and:IX WCAP-15777 January 2002 5842-App doc O21902

B-9 j:7'V2. 1 fly~~~ m~hn~~ma~ vnulyPreceded by All discoloration, fuSred t ermel cit 4tj 4*

odr.ea or~ cut 3u~rfaceo rea~ 119 ater* end l; thier~mal cu-ttin- slhell bc rem~oved.b or~rndin; the dOPth tu be Mltohincd Or ground iha!!

~

Visually and by liquxid pelletr.ar rjna,

  • to gpe"ification Ila.2.6 7.2.3 By rsuL f a c, C t dfF?* o ~ we L A e " ~ r d i h~

Wt~l~ngaccrl& to Cpccificatj 0,,,- )'.5.L

-.7,3 Nri,~ 1at ~ ~v~cd As ars eedcifor Correct. asrcepv.,y.

2lY tack Aycldz deposited in the Cldo~e 7.5 ~ dce n t) k__ r BY grinding, wire bruCh,'Ij s

2 xwith ut~j rless Stee subsequent wipitnC Nwitth a Clothl ooale Iai~

il bctoe WCAP-15 777 5 84 2App~o> 02 190 2J an u ar y 2 0 0 2

B-10 4- '-'n 1.0z . 1.

  • t.6 * * .7 -1<

5 r

I i2~;

A~ter

)d ~.c~: ccc . at 4ac by ~r ct -

  • WC ~ m 5 7 7 7J i842-App.doc02 1902 a n ua ry 2002

B-11 Tit- layer -Aid 'Ofo-~o Weld thie-knes&.

If back 0t1PP-i. n OT .&r~indig i&; perfO~ed on the, ro o -6paz tthat area shall also ~oliquid rpenetrtant exam~ined.

.3.2 Sncifio.

lds b&Wtea. 1T 6 7i ins t~~on tubree a-nd bottii he6ad each laver awltrolZad dri.va hounings first layer and and toT) 1'x'ca'd each Alt of wald vent pipe and top .1 , 1,0(7.3 1 . c' _

Acco x'nLg to thijs specification, No reql.idroxrnents.

10. Surfai--o ondtitonirg.

Smooth'mincg of Wolded joints by Mechanical meanL as ~

needed for exami~nation anid/or QesiGxi.

ii.-aton ofvil odints.

-,By liquid. penetra4it, Czalairation accord~ing to 'a OPii 0.atiC, No, 24.0,6.

'Aic ov 1ngr o sP<ifcaillb. 39.04.

5 WCAP-15777 5842-App. doc-02 [02 January 2002

Cl Cl C

C C]

-- - I C.--,- I

- -rf ,"

I /

I.

I I

K<

/ j'jF

/

-1I I I '<

1 It

-F----- j:z Ni C

fj 4, I 4

Q 1

Q¶OAJ r4 Z\ '*

Nd a' A

St "'3/4 \G. C' C-ri

- N Na' - C--C an C- -.-,- - -

-ýI (41 CD~

B- 14 Icoi to Inconej (AS.-IB

-66 167 or i~)b "10 1113V o backiag ItixIp.

Strin "Vr.e and.o~

Ar~G b c:.~.nc I g~ 3~a 1 -9~ usedj 'Or bUtt ueldo h y~ t ci'~ ~~ snt~eossibla

_a rh c~1 for CgrcU*

n nd 2.2 ViAn t2 z ... 3 ___

-~ st~i 1 tro~z n veave tra-:el.

ngeaj width limited to 25

!azi 1G and 35 (upward)

F-N'umbo43o4E:b soi ir ra 1)toS~5 rodr 0.81, 1.0, 1.6, 2.0 dr 2.4 z shielolin; gas ar- I- nq..jq W CAP -15777 J n ay2 0 5842-App~doc O'21902 a ua y 2 O

B-15 6-.

-~$rDaration.for ie'ldig 4

'6j u ifcat en,.

I- acodnc vtl equiremen-ts olAS I1and I1Ž 6.2 Wefd ee.

e 6.2.1 Prennrcti oa.

By mechanical means evontually, preceded by theral cuti'Lp, All discolorntion, fused cdgos of out aurffaeas and qjtin reiir.ig after ther-ma] cutting rhall be removed -by meachining or grinitng: the depth to be machihed or g.04' shall be at least 0.8 r-n.

6.2.2 37amIrat1C 1M,2rc Visually anA by liquid pcnetr-nt CXAIin...n rceor-ir4 to Mocfiaia

i. 24'.06.

&.2.3 Reanaret nt"

.. d eees By surface Conditioning, followed, if required, welding accordil::g to sncoifi cation Nlo. 390,.N.

6.3 M-iarkinr of rcrts to be w.lded.

As fur as roodud for correct arscrl,-..

6.4 Taski.- "

By tack -celds deposited in the weld groove.

S6.5 Clermin, of *eel* -.e *rand tan..

'-By gr'inding, w,*re brufshiinG v'it-h welda.

stainless AU, artd sube~quett w ~ng uwith a olath. sjoakted:j-in a m WCAP 15777 January 2002 584'- App.do*-02t902

B- 16

' 1 C T!iýg I -

V.

-r

&4 7.

a rgon dc, £TL Ow ra to i-,l l/L-i a~.70-1 0 6-&

2.0Q 100 -1 5 6-2.4 0 In r -dc.,ria d ia!'z fe-lsotrZ 0.0ldll 90 - 4 13 11 72 Surface of v-rld b.eada to be co~t4Q for Coo a,;. C' Alter each -.Kl] paso removal. of oy:ide by wire b-.',;rin:w iyith stail1e.ns aiteel brizshe-,s.

flyra- ~irjon -iudp~~rn a COT6)I l

- . v l ý- - _

5842-App.d~ic02 1902 January 2002

B-17

.)4 I

K zbt 1sIkýer a9n4,:6iCh-.1 of we]A thiokneoan Iftbbaok ih~ippiing .or.grinding is' 'peiformad. on tk rc ý

"'thet o:ab iuiq.d 'ent'!a exane0.

7ý32 Sipecifie..

weed a betw"cn ~4 ~ *

ins-triTmen4to ao o t':be- ac 1,e

'4 and botto= head control rod drive hoizln~s first layer r-nd.

of' ul a

  • 7-4 Inte=r.Rdiatr- rarxr.

AcedidIn~g to t~i~s specificatio~n. .

Smnoot hcnin~g of w~elde'd .jointzn b, a~~c~ fJen~a needed for examination and/or d~niin.

  • xO.inratSon of wpidee ji C nt-.

My liquiq panetrant exp-inationa ocording to sý i~~'r No 2406_________________

_ _ __ _ __ _ _ _ _ _ _ _ _ 0 WCAP'-15777I 5842-App. doc-02 1902 January 2002

22 cI C-i CD

B- 19

  • 1* -.

~.~fnaa~anwaý.

.- 11 a 1 13 r -, . 74 T"

';t: ý;,.j F

C ii I.

V a. -.

NA

- an..

V

- 'VP, A 4P VXJ- ADA 1;777 5842-App. doc-02 1902 January 2002.

B-20 dv 4

4~b I

verae Is (L

lo.~l~refor repair weldingofTcnx(-hme4)

~ax01. weldmonts.,

II 44 '1CMA V $

r

  • ~ APPROVED.

4 CAPR~i AS NOTED 0l RESTURHtD) FORPgCrQ 1 Li4

_)CAT BY _ _ _ _ _ _ _

1' 5ý9.04-5390 6 MA 6 T+/-

WC-'App o 015777 5842App~oco21902January 2002

B-21I

-in eccomdance with ra'quii-r~emLerXts Of ASMM III aa~d IX.

TWtI.4,jVIr: :t-aftgl! qac...

.2.1 Manrnnl 22-2 tunzrten arc weldinn.

String and/or weave travel.

ntavin, width-lim~it-ed to ,3 mm.

2.21anual chielded rteta io i&din.

String and/or wreav~e travel.

VWeavirg width limited tor 2 timies electrode diametex'.

2.3 Comrn'Anation of 2.1 and-2.2.

0 3. Vfaidinf! i~ositjo 1 1 s*

IG and 2G- for par. 2.2.

3G- (mdc. *of axis 30* + 150) for par. 2.3.

4.1 Dfanv~l aas tunrzv.ten P.zc weldling.0 P-lu~mnber 43. bare solid filler rod according to ASTO SB-304 ER 2NiCr -3 (S1-A-5.14).

rod diametler 1.0, 1.6, 2.0 and 2.4 mm.

shielding gas: argon 99.99 ~

4.2 Manuai1 shie~lded nietal arc ureldlnq'.

I ----

Repairý welding olf Inconeli., 39-Z4" -6 n4Wtfrr WLAY-1 /I / January 2002 January 2002 5842-App.dtjc-02 1902

B-22 4*.. J +

ode to

-AM;:~ 60465 B .TifC F-e. - I (S*.,.

  • 1').

- *:*+,++++ i~z~iim't-ft.l- za Ve weld&=m4.a-alme

-2;, .£ Inco=n.l weld oevrlaý Cladding 0..-11 -Ymax, 5.0 - 9.5 5%

r 15 % max.

  • S. 0.015 % max.

.Si 1..0 % max.

0.50 % max.

1.0 % max.

12.5 - 17.0'%

-b + Ta 1.0 - 2.5 %

0.12 % max.

others 0.b5 %max.

Ni balance

5. Dr.rii aand storage of welding materials.

Covered electrodes according to specification No. 54.01.

6. Preheat and interrass temnerature.

6.1 Range  : 15 - 175" C.

~9.Q4 I 6.2 For repair welding of first p~f~ 6 4 o(

layer of Inconel w'eld overlay cladding (clad thiokness up to 2.5 mm) on P-12 B mnaterials;

-RInge,: 100- 175' C.

To be .maintained &uxiag welding and subs~eqaent to weldi~ng

-1 0

wldiigof tnconel.

R~~~i' WCAP-15777 January 2002 5842-App.doc-021902

B-23 I~~.ti~torat on. for weldlitu.i Ou,1allf ~tios F

'in accozrdamce with requiTsewnts -of kSIM.1flI -and I-I.'

i,.

7 .2 Arzn to be re-airyd.

7.2.1 Lprea.:at'on.

By mechanical. means a.z far as needed for removal of defects and correct repair wel&ing.

7.2.2 Exeninaticn -r-repared .-L'asz Visually and by liquil penetrant examination according to specification. No. 24.06.

0 7.2.3 Ole--.ning -rerared areas.

UWith a cloth soaked in acetone.

S. 'Welding.

8.1 Data.

8.1.1 Marnil0 rtas tuni~sten are wa2.dinal.

diaractei' tu~n~zten

(,eý thoriated),

Iwelding. ctirrent in amups, d.o.0 argon flow ra~te electrode in mm., electrode' - in 1/min.

1.0 <'80 6 - 8 1.6 TO - 140 6 - 8 2.0 Ia-156 -8, 2.4. 0I - 250 6 - S.

0 ninnaaa

ý9.04-Ropair vielding of Incozzel.-

WCAP- 15777 January 2002 5 84-2-App. doc 021902

B-24 g:, *oz l repair welding of firat l~ayer of Inc onel weld overlay Ig OC~ad~d~hg on P~-,12B 'mate l2..

<' 4 mm atd 90 - 110 .amp.only.1

8.2 Surface of we-id beads to be conditioned for go od appe*a.'ancc.

After each weld pass removal of eventual slag by grindingI

<* *and wrire brushing with stainless steel Wire'brusbes.

0'__,; Examination du.ring repair welding as specified for the oriinal. weld.

9. Posthoatinr.

No In requirements.

case of use par. 6.2: subsequent to weldLng temperature to be raised to 205 0C and held for two hours, after which

~cooling down to room temperature is permitted.

10. S1rface condwion njr.

Smoothening by mechanical means as far as needed for

.,. ~ examination

~Rep~air and/or design.

weld.goficoe

'9. Po ' ca9.04 '

WCtAoP- 15777 January 2002 5842-App.doc-021902

Z061ZO-,x)pddV-Zt-,gý

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-- aaooUj To DUTPILWA CTUdad VO ýIlv-cýýauadl apctij @Ct P-20 01ýj so juaoaof: OL Z70 -0

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