ML20151R882

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Rev 1 to Characterization of Intergranular Attack in TMI-1 Once-Through Steam Generator Tube Samples
ML20151R882
Person / Time
Site: Three Mile Island Constellation icon.png
Issue date: 10/03/1985
From: Croneberger D, Giacobbe F, Janiszewski J
GENERAL PUBLIC UTILITIES CORP.
To:
Shared Package
ML20151R847 List:
References
TDR-686, TDR-686-R01, TDR-686-R1, NUDOCS 8602060297
Download: ML20151R882 (57)
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Text

-

A?PENDIX C-

<0 686 I g TOR NO. REVISIEN NO.

BUDGET 123125 I 23 TECHNICAL DATA REPORT ACTIVITY NO. PAGE OF PROJECT: ESD/ Mat Eng/ Failure Analysis DEPARTMENT /SECTION TMI-I OTSG Recovery REVISION DATE 10/03/95 RELEASE DATE DOCUMENT TITLE:

Characterization of ICA in TMI-l OTSG Tube Samples ORIGINATOR SIGNATURE DATE APPROVAL (S) SIGN ATURE DATE p

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J. A. Janiszewskiy[( ( , f ll/M F.S.Giaco$e(( ja/t/f

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  • DISTRIBUTION ABSTRACT:

D. K. Croneberger This report describes the additional investigations to R. J. McCoey further characterize the intergranular attack (ICA) that S. D. Leshnoff existed in the OTSG'1 as a result of the thiosulfate intru-J. J. Colitz sion into the RCS in 1981 as well as help clarify the sensi-G. E. Von Nieda tivity and accuracy of eddy current examination for R. F. Wilson ICA/ICSAC. Unf ortunately, this investigation was unable to produce any data or conclusians regarding the detectability of ICA by eddy current testing.

Existing reports were reviewed and reported IGA areas were characterized. Tubes that had been previously removed and stored were eddy current and fiber optic inspected. Two tube sections were also cut and examined by metallography.

ICA in areas away from identified intergranular stress-assisted cracks (ICSAC) and away from stained areas were found which were approximately hemispherical and penetrating less than 40% through wall. Visible pitting was found to be less than 0.005" deep and .005" in diameter.

Stains present on the tube I.D. do not describe the geometric shape of underlying ICA. I,arge areas of staining exis t without significant ICA. These stained areas, however, may contain discrete, randomly distributed patches of ICA. ICA surrounding visible pits may exist but is not deeper than the pits and extends no further than twice the diameter of the pit.

No evidence of axial cracking was detected in the OTSC'balow the upper tubesheet.

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TDR 686 TITLE CHARACTERIZATION OF IGA IN T'tI-l OTSG II3E CAMPLES REV

SUMMARY

OF CHANGE APPROVAL DATE 1 Abstract: Abstract has been completely rewritten. y/q/g Ref. to grain disturbance has been deleted.

1 Pg. 3: Introduction has been completely rewritten.

1 Pg. 8, Table 2: Deleted "none" under stain description. ,

1 Pg. 11: Paragraphs 2, 3 & 4 rewritten for better clarity.

1 Pg. 14: Deleted statement regarding 2:1 extent to depth relationship.

1 P;. 16: Table 6: Deleted column labeled " Percent of IGA ir. thia Group" 4

1 Pg. 17: Deleted para. on Grain Boundary Separa-tions.

1 Pg. 18: Deleted Figs. 6a & 6b.  !

(Rev. 0) l 1 Pg. 18: Conclusions d1(6 deleted 1 Pg. 19: References #2, 4, 11 deleted (( -r M <e/5/p r

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TDR 686 0 m Rsv. 1 Fcgg 2 of 22 TABLE OF CONTENTS PACE Introduction 3 Methods and Sources of Dats 3 Results and Discussion .

ID 0xide Stains 5 Eddy Current Inspections 8 ,

Metallography 10 Characterization of ICA 14 Frequency of Occurrence of ICA 15 Grain Boundary Separations 17 Conclusions 20 References 21 Appendix 22 u

TDR 686

' ' R:v. 1 Pcgo 3 of 22 INTRODUCTION Indications of greater than 40% TW penetration identified during the 1934-85 EC examinations indicate that IGA /IGSAC of this depth did exist which were previously below the eddy current voltage response required for dispositioning of a defect. As a result of mechanical loadings on the actual OTSG's, these pre-existing ICA/IGSAC areas have probably been disturbed producing local grain boundary separations or loss of grains which enhanced their voltage response perm tting a signal disposition (Ref.1).

In order to attempt to describe and quantify pre-existing ICA, CPUN initiated a laboratory investigation at B&W's Lynchburg Research Center (Ref.

2). This investigation used actual OTSG tubing that had been removed from the OTSG's in late 1981 and early 1982.

The results from the LRC effort were then analyzed in conjunction with previous analyses of ICA/IGSAC in order to describe ICA/ICSAC that might exist in the OTSG's at the time of the 1984-5 EC inspections and its relationship to stains and eddy current indications.

METHODS AND SOURCES OF DATA The principal source of data used in this analysis was the investigation done by B&W's Lynchburg Research Center (LRC) from February to April, 1985 ,

(Ref. 2). As a supplement to the above analysis we used the results of additional eddy current testing done by Nuclear Energy Services (Conam) on the same group of OTSC tubes.

To increase the database on in:ergranular attack, we reviewed previous reports (Ref. 3-7) on failure analysis and long term corrosion testing of TMI-1 OTSG tubes.

For the 1985 B5W investigation, we selected OTSG tubes that were from the periphery of the A-0TSG. These tubes were renoved between late 1981 and mid-1982 for use in the TMI-1 OTSG failure analysis. They were stored at LRC since that time.

In order to make eddy current testing meaningful, the tubes had to be at least six inches long. The final set of tubes (Table 1) consisted of fourteen tube sections.

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TDR 686 Rev. 1 Page 5 of 22 B&W metallographically examined samples cut from two of the tube sections. Details of specimen selection and preparation are contained in Reference 3. >

RESULTS AND DISCUSSION I.D. Oxide Stains We examined the oxide films both directly and indirectly. Indirect examination was done on all tubes using fiberscopes as previously described.

Direct examinations using a stereo microscope were done on tubes A-lll-13, piece 1 and A-ll2-5, piece 1, af ter the pieces had been longitudinally sectioned. The direct examinations were more sensitive.

We identified three types of stains during the direct examinations.

Type 1 stains (Figure 1) consist of small (approximately .010" diameter) darkened areas that resemble oil spots. They do not have any visible internal structure and are not associated with any underlying tube defects.

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TDR 6%

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$ Type II stains are from approximately O.25" to over la irregularly shaped (Figure 2). Their internal color is a dark brown, and there is a distinct border between the stained area and the balance of the tube oxide film.

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l Type III stains are similar to Type II in extent, overall color, and in the presence of a border. However, within a Type III stain there are one or more areas which appear grey in color and are usually accompanied by grain loss which appears as small pits. (Figure 3). The pits are on the order of

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L The fiberoptics examination was not sensitive enough to detect Type I stains. We did identify several areas which could be identified as either Type II or III stains.

Table 2 compares the fiberscope observed locations of stains to the locations of eddy current indications in the tube samples. Tube A-112-5 is listed separately because of the large number of eddy current indications in it (see next section).

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TABLE 2 - Correlation of Eddy Current Indications With Stains Detected by Fiberscope Tube Sections l Other EC Indication StainDec.;(g; ion, at Stain Location? than A-112-5(1)

No 6 l Type II l Yes 0 l

l No 0 Type III Yes 5 Note 1 - Tube A-112-5 not listed because of large number of eddy current indications.

l For tube sections other than A-112-5, Type It stains did not correlate l

i with eddy current indications, and Type III did. In tube A-112-5, some Type II stains appeared at addy current indications. However, with the combined

  • imprecision of both eddy current and fiberscope measurements with respect to axial location (elevation), the stain - indications match is suspect for this tube.

Eddy Current Inspections Table 3 presents a summary of the results of both the Conam and B&W eddy current evaluations. B&W's evaluation (Ref. 2) concluded that there was no significant change in the eddy current results between 1981-82 and 1985.

Conam reported all indications that were visible above background, regardless of voltage level.

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TDR 686 Rsv. 1 Pcg2 10 of 22 The results of the eddy current inspections were consistent with both previous inspections and each other. Of the fourteen tube sections, nine had no detectable defect indications, either reported previously or by the current inspection as evaluated by Conam. Three more had previously reported indications that were confirmed by the present tests.

The two remaining tubes had previously identified indications which B&W confirmed had not changed since the previous examinations. During the Conam reevaluation of thene tubes, additional indications were identified. In tube A-112-5, piece 1, Conam was able to individually evaluate signals previously identified as " multiples". In tube A-111-13 Conam reported two additional indications in an area where B&W had previously reported a possible defect.

The reported indications were low level, less than 1 voit and their detection may be attributed to improvements in analysis equipment and techniques from 1981 to 1985.

The indications in these two tubes were further characterized by metallography. The result's of this characterization are described in the metallography section of this report.

Metallography We selected tubes A-111-13, piece 1 and A-112-5, piece 1, for metallography. We had two objectives in the metallography: First, to determine the presence and severity of intergranular attack (ICA) under stains and second, to determine if ICA was detectable by eddy current testing. We felt that these two tubes were the most likely to provide useful data, since they both contained low voltage eddy current indications (below normal reporting level).

The first part of the investigation consisted of sectioning both tube sections longitudinally. Tube A-112-5, section I had 15 visible circumferential cracks in it. It also had a large number of stains of all three types.

We selected two areas from this tube for metallographic examination.

The first was an area from 1.125 to 1.802 inches from the top of this section. This area contained a large Type III stain.

We made four transverse cuts through the stain and characterized any ICA and pitting.

We found only superficial ICA (less than 0.001") under the stains. We ground into three areas of pitting; the deepest pit was 0.005", while the other two were less than 0.002" deep.

We took another transverse section through a longitudinal stain that contained a longitudinal line of pite at shout 2.75 inches from the top of tube A-112-5. Again, only superficial ICA appeared under the stains, and pit depths were less than 0.002".

TDR 686 I Rev. 1 Pass 11 of 22-Tube A-111-13 had considerably fewer stains on the I.D. surface. No ,

cracks were visible. but we observed individual or clustered pits near the k reported eddy current locations. In order to characterize the pits and check for circumferential cracking, we took three longitudinal specimens at locations corresponding to eddy current indications. After completion of several successive grinding / polishing steps. we broke the tube sections out of their mounts and bent them slightly with the ID in tension. We also bent che unsounted sections of the tube. We found circumferential cracks at all three eddy current indications in tube A-111-13.

The results of the metallography indicate that staining is not indicative of areas of general ICA.

Both direct visual observation and metallographic examination suggest that the pits are formed by the drop out of a small number of grains in a ilmited area of IGA. The deepest pit examined was 0.005" deep, or approximately 14% through the wall. Most of the pits were less than 0.002" deep.

Finally, this metallography was not successful in determining the detectability of ICA by eddy current. Table 4 attempts to correlate eddy current indications. visual and metallographic results, however, due to the close proximity of indications to each other and the imprecision of location measurement these correlations can only be considered approximate.

TABLE 4 - Correlations of Eddy Current Indications and ICSAC EC ANALYSIS CRACK CHARACTERf2ATION LocationI "

- In. From Top 8 X 1 Result Location (3) of Piece .540" Re b #Collaof Volts (2)1n. From Topt T.W(.10) Length Tube ID .540 8X1 % T.W. Volts of Piece in.

Tube A-112-5 0.3 0.55(4)100 1.55 3 2.45 .549 100 .31 0.9 0.85(4)100 1.32 2 1.42 .754 100 .14.12(1) 1.1 .69 1 0.29 1.095 100 .09 .15(13 1.4 1.05((4) 70 ,2.58 1 0.95 1.357 100 .26 1.35(4) 1.65 4) 91 2 2.81 1.631($) 100 .15 1.701($) too ,og 1.759(5) too ,1 1.95(4) 1 0.24 1.930 100 .25 2.05(4) 2(6) 0.32 2.053 100 .19 .24(1 2.4 2.3 83 .87 2 0.44 2.301 100 .2 2.6 2 1.48 2.556 100 .23 .29(1 2.9 3.0 85 1.09 3 6.98 3.195 100 .32 3.2 83 1.22 1 2.90 Note 7 .

3.5 1 3.47 Note 7 3.8 2 10.0 3.640 100 .26

TDR 686 I e . I Rav. 1 Pcg2 12 of 22 t

TABLE 4 - Correlations of Eddy Current Indications and ICSAC (continued) ,

f EC ANALYSIS CRACK CHARACTERIZATION Location (

In. From Top 8 X 1 Result Location (3) of Piece .540" Result _ Colts Volts (2)1n. From Top % T.W(.10) Leng

  1. of Tube ID .540 8x1 % T.W. Volts of Piece in.

4.1 4.0 87 4.95 2 1.01 4.025 100 .31 Tube 112-5 4.7 84 1.71 4.9 4.9 96 0.71 1 .09 4.80 Note 8 5.8 5.7 80 2.55 3 4.32 5.380 100 .31 1.2 23 1.57 2 .45 1.0 20 0.25 Tube A-111-13 1.2 .175 1.5 1.5 96(13) .79 2 1.04 1.5 20 2.1 2.1 46 .63 2 .59 2.8 29 .037 (9)

Notes:

1- Based on interpretation of tapes w/ assumed constant pull speed.

2- Maximum coil voltage 3- Based on in-laboratory measurement 4- Locations less than 2.3 inches from top have had 0.15 inches subtracted from Conam reported locations to' account for apparent non-uniform probe motion.

5- Cracks too close to resolve by eddy current 6- Colts were not adjacent 7- Heavy pitting but no cracks observed. Specimen was not examined by bending 8- No cracking - cutting tool damage to 1.D.

Up to .148" may have been lost during cutting and mounting for l 9-metallography.

10 - Approximations only.

11 - Crack depths over 80% are administrative 1y treated as 100%.

12 - Crack only visible running to cut edge of one half. Length ranse based on measured sawblade width of 0.055 in.

13 - EC signal was alanificantly distorted

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TDR 686 R3v. 1 Pcg2 13 cf 22 Figure 4. compares the observed length of cracks with predicted ranges for the number of coils reporte<* by the 8 X 1 probe. The data show that in general the observed crack lengths are consistent with the reported number of coils, except for two one-coil defects which were longer than predicted.

These defects were probably either misaligned such that a second coil would pick them up at a level too low to be reported, or manufacturing tolerances in the 8 X 1 probe caused one-coil coverage to be larger than predicted. By CPUN plugging criteria, these indications would have been combined with adjacent indications and the tube dispositioned conservatively.

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  1. of Coils Detected by 8 X 1 Probe Figure 4 Measured ICSAC length vs. number of coils by 9 X 1 probe.

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. . TOR 686 Rsv. 1 Pcg3 14 of 22 Distribution and Characterization of_ ICA Data Base Data on the size, shape and frequency of occurrence of ICA have been generated from several previous investigations as well as the 1985 program at f.9C . As part of the present data analysis effort. we compiled available data f rom metallography samples reported in the following investigations:

1) First and second round failure analysis at B&W and Battelle -

References 3 and 4

2) Third round f ailure analyses at B&W and Battelle - References 5 and 6.
3) Long term corrosion test at Westinghouse - Reference 7.

We have reviewed each of these references and extracted reported data on the amount of tube surf ace metallographically examined and any ICA detected.

Relevant data from each reference are contained in Appendix A.

Characterization._of ICA A total of twenty areas of TCA have been detected (Table A-1). Nine of these areas were within 0.5 inches of an identified ICSAC. while eleven were more than 0.5 inches away. The bulk of this discussion is based on ICA away from ICSAC, since this should be representative of the ICA which could potentially have remained in service in the OTSC's. .

The ICA areas away from ICSAC generally appear bowl-shaped. Figure 5 shows the extent (axial or circumferential length) to depth ration for the ICA. The ICA areas near ICSAC tend to be deeper for the rame axial length.

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  • TDA 686 Rsv. 1 Page 15 of 22 The maximum depth of ICA detected away from ICSAC was 0.013 inches, or 38% of minimum wall. The mean depth was 0.0061 inches, with a standard deviation of 0.0036 inches. The mean depth of this ICA was 0.011 inches, standard deviation was 0.039, and maximum depth was 0.020 inches.

The mean axial and circumferential lengths of ICA away from ICSAC are the same: 014 in. This is approximately twice the mean depth of 0.0061 in.

This confirms the bowl-type geometry of the ICA away f rom IGSAC.

Frequency of Occurrence of ICA In Table 5, we have summarized the frequency of occurrence of ICA. The frequency figures are based on the total length of examined surfaces.

TABLE 5 - Occurrence of ICA in Meta 11ography Samples Longitudinal C ircumf erential Samples Samples Total Met. Sample Length, Within 0.5" of ICSAC 3.053 in. 4.347 in.

Away from ICSAC 1.278 in. 81.508 in.

Total 4.331 in. 85.855 in.

Length of ICA Areas, Within 0.5" of ICSAC 0.106 in. 0.048 in.

Away from ICSAC 0.019 in. 0.150 in.

Tot.s1 0.125 in. 0.198 in.

Percent of Sample Length Occupied by ICA Within 0.5" of ICSAC 3.4 % 1.1 t Away from ICSAC 1.5 % 0.2 %

Average - all samples 2.8 % 0.2 %

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  • TDR 686 R:v. 1 Pcg3 16 of 22 Both overall and in the specimens more than 0.5 inches away from identified ICSAC, approximately 0.2% of the transverse specimens' surface contained ICA. Near IGSAC, the ICA-occupied length increased te 0.9%. For longitudinal specimens, the % of ICA was approximately 3% overall, 3.6% near IGSAC and 1.5% away from ICSAC.

The logic for sampling the transverse and longitudinal specimens was different. Most longitudinal specimens were selected based on mounting a surface feature of interest, such as an ICSAC, stain, or pit. The vast majority of the transverse specimens, on the other hand, were C-ring specimens from the long term corrosion test. As such, they were selected to represent a sample of tubes, heats, and elevations, and thus should constitute a more representative sample of actual tube conditions. The transverse specimens also constitute a larger sample than the longitudinal ones; approximately 20 times more tube surface was examined in transverse mounts.

In Table 6, we present the analysis of ICA distribution by height. The percentage of sample length exhibiting IGA ranges only from 0 to 0.6% - this is a relatively narrow range. Therefore, within the limited data base the It f requency of ICA does not appear to be strongly dependent. on axial height.

should be noted, however, that we have removed no tubes below the 9th tube support plate.

TABLE 6 - Distribution of IGA by Height in Transverse Samples Distance From Percent of Total Percent of Met. Sample Sample Primary Face Exhibiting ICA of UTS, In._ Length 0-11 36.9 0.2 11-16 3.1 0.6 16-24 15.4 0.0 24-70 44.5 0.3 70+ 0.1 0.0 The C-ring samples examined in the long term corrosion test form a subset of particular interest. These samples were selected to represent a variety of tubes, heats, and elevations, away f rom IGSAC. As a consequence of the post-test examinations (Ref. 7), these tube sections were thoroughly examined for ICA and IGSAC.

Table 7 summarizes the results from tubes used for C-ring samples.

Except for tube A-24-94, all ICA was found in the upper tubesheet area in tubes which also contained rejectable eddy current defects.

TDR 686 Rav. 1 Pcg2 17 of 22 Table 7 - C-Ring Sample Examinations from Long Term Corrosion Test Examination No. of Elevation, In. No. of C-Rings  % of Transverse from Primary C-Rings C on taining Length Occupied Tube Face of UTS Examined IGA by ICA(2)

A-62-8 5-8 5 1 0.05 49.5-52.5 5 0 0.0 A-37-29 A-88-7 10-13 3 0 0.0 A-24-9's 25.5-29 5 4 0.8 A-13-63 20-21 2 0 0.3(1)

B-16-22 60-63 3 0 0.0 A-16-69 2-3.5, 9 4 1 0.2 B-94-27 18.5-21.5 2 0 0.0 534-19 6.5-7.5 2 0 0.0 Total 31 6 (1) Includes 1 area of ICA found on full tube specimen taken from tube next to C-rings.-

(2) IGA occupied 0.2% of the total C-ring length examined.

Tube A-24-94 has been previously recognized as a tube with an inordinately large amount of both ICA and ICSAC (Ref. 9). No reason has been identified why this tube should be the worst of the 29 tubes removed from the OTSG's. It should be noted, however, that this tube would have been removed from service because it contained ICSAC of greater than 40% thru wall

' penetration.

TDR 686 Rsv. 1 Pega 18 of 22 CONCLUSIONS

1. ID tube stains do not represent areas of significant IGA. IGA observed under stains is typically less than .001". Some IGA exists near visible pits, but it is usually less than 0.005 in. deep.
2. Visible pitting is small, less than 0.005 inches deep and wide. Pits of this size are below the expected detectability for eddy current testing. 'They are

- visible by fiberscope inspection.

3. IGA areas occupy, on the average, 0.2% of the examined sample length. Within the limited sample examined, there appears to be a uniform axial distribution of the localized ICA.
4. No conclusion can be drawn from the available data presented in this report regarding the E.C.

detectability of ICA not associated with ICSAC.

5. No axial cracks have been detected below the upper tubesheet region.
6. Measured circumferential length of ICSAC correlates well with the number of 8 X 1 coils on which the signal appears.

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  • Rev. 1 Page 19 of 22 REFERENCES 1- J. A. Janiszewski, " Evaluation of Eddy Current Indications Detected During the 1984 Tech. Spec. Inspection," GPUN Technical Data Report 638, Rev. O, Jan. 11, 1985.

2- S. C. Inman " Investigation of ICA in TMI-l OTSG Tubes," B&W Report RDD:

85:5046-03:01, June 1985. (Attached) 3- M. A. Rigdon and E. B. S. Pardue, " Evaluation of Tube Samples from

' TMI-1," B&W Report No. 77-1135317, July 7, 1982.

4- A. K. Agrawal, W. N. Stiegelmeyer, and W. E. Berry, " Final Report on Failure Analysis of Inconel 600 Tubes From OTSG A and B of Three Mile Island Unit 1," Battelle Columbus Laboratories, June 30, 1982.

5- S. C. Inman, " Examination of OTSG Tubes f rom IMI-l Third Pulling Sequence," B&W Report RDD: 83: 5068-03-03, December 1982.

6- A. K. Agrawal, W. N. Steigelmeyer, and W. E. Berry, " Final Report on Failure Analysis of Inconel 600 Tubes from OTSC A and B of Three Mile Island Unit 1, Battelle Columbus Laboratories, " June 30, 1982.

7- "Long Term Corrosion Test Program of Nuclear Steam Generator Tubing Samples from Three Mile Island Unit 1 - Final Report," Westinghouse Electric Corp., May, 1985.

8- G. E. Rhedrick, "Tr.sk IV Report on Eddy Current Indications Found l

Subsequent to' Kinetic Expansion of TMI-1 Steam Generator Tubes," GPUN Technical Data Report No. 401, Rev. O, April 8, 1983.

4 4

- , . , , _ - _ . - - -y,, y -- _ _ - - - - - -,m, , , , - - -

  • TDR 686 R;v. 1 Page 20 of 22 Appendix A Sumary of Meta 11ographic Samples From Laboratory Investigations

. TDR 686 .

Rev. 1

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Page 21 of 22

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TABLE Al - ICA Detected During Meta 11ographic Examinations Type Length of ICA Extent, mils Elevation Specimen of Documentation Sample Length Elevation of Depth Nearest IGSAC Ref. Page/ Figure Note OTSC Tube In. From Top Specimen (l) Examined, In. Axial Circum

.041 .014 .019 1.21 4 F 17 B 8-25 1.25 L

.012 .015 1.25 4 F 24 (2) 8 11-23 1.25 L -

.027 X .036 .011 .025 10.5. 4 F 37 (3)

A 146-6 10.5 SEM

.035 .020 .020 10.5 4 F 38 (4) 10.5 L

.008 X .006 .004 .004 3.75 4 F 49 (3)

A 146-8 7.0 'SEM

.035 .015 .004 3.75 4 F 50 8.5 L

.016 .003 .0014 5.5 5 F2-32 (3)

A 24-94 5.5 T

.028 .004 Top 5 F2-44 B 16-22 .125 L .105

.030 .010 32 7 F7-59 A 24-94' 28 T 2.63

.007 .004

.015 .002

.005 .003 32 7 F7-59 28 T 1.46

.035 .009 32 7 F7-67 26 T 2.63

.009 .004 32 7 F7-69 29 T 2.63

.006 .008 32 7 F7-78 27 T 2.63

.006 .004 4 7 F7-84 A 62-8 8 T 2.63

.020 .016 9 7 F7-105 A 16-69 9 T 1.46

.020 .013 16 7 F7-120 A 13-63 11-20 T .87

.013 .013 .005 3.6 2 P 15 A 111-13 3.6 1. 1.0

.008 .010 4.8 2 P 15 4.8 L 1.0 Notes:

1- L - Longitudinal, T - Transverse, SEM - SEM exam. of surface 2- ICA at end of ICSAC 3- Measurement taken on surface pit with ICA morphology

TDR 686 Rev. 1 Pega 22 of 22 TABLE A2 - Meta 11ography Ssmples Not Containing ICA Specimen Type Length of Surface Elevation Examined, In. of Do:umentation Elevation of Ref. Page/ Figure OTSG Tube In. From Top Specimen Axial Circumferential Nearest IGSAC .

.085 8 3/16 3 P63 A 12-62 8 3/16 L P64, 65 13-63 1 T, L .060 .080 1.125 3

.075 .060 8 5/8 3 P66, 67 B 33-30 8 5/8 T, L 3 FG1-6

.055 .060 27 A 13-63 26 5/16 T, L 3 FG7 62-8 11 7/8 T, L .060 .060 NDD

.060 .060 9/16, 1 1/2 3 FG8 133-74 1 T, L 10 5/16 T, L .060 .060 10 11/16 3 FG9

.060 .060 -23 5/16 3 FC10-12 23 5/16 T, L

.060 .060 33 3 FG13 32 3/4 T, L FG14, 15 35 3/4 L .060 .060 33 3 B 33-30 32 1/4 L, T .060 .060 8 5/8 3 FG19 L .020 3 4 F30 A 71-126 53.5 4 F31 L .015 3 54 A 146-6 8.5 L .130 8.5 4 F35 L .008 3.75 4 F42b A 146-9 1.0 4 4.0 L .040 3.75 F47

.012 3.75 4 F51 0.5 L 4

.038 3.75 F52 0.25 T T, T .028 112 5 F2-31 A 37-29 110 T .160 Top 5 F2-37 B 34-19 Top

.075 .140 5 F2-42 B 16-22 .140 T

.110 T .192 Top 5 F2-43a

.128 Top 5 F2-43b

.110 T

.125 L .105 Top 5 F2-47 L .055 Top 5 F2-45 B 16-22 Top 2.63 3 7 F7-24 A 62-8 5 T 49.5 T 2.63 112 7 F7-25 A 37-29 10.5 T 2.63 6 7 F7-26 A 88-7 2.63 34 7 F7-27 24-94 25.5 T T 2.63 16 7 F7-28 13-63 21 T 2.63 NDD 7 F7-29 B 16-22 60 62 T 2.63 NDD 7 F7-30 T 2.63 4 7 F7-32 A 16-69 3 T 2.63 6 7 F7-38 A 88-7 13 18.5 T 2.63 14 7 F7-40 B 94-27 2.63 112 7 F7-42 A 37-29 50 T 51 T 2.63 112 7 F7-44 2.63 NDD 7 F7-46 B 34-19 6.5 T 7 T 2.63 NDD 7 F7-48 2.63 14 7 F7-50 94-27 21.5 T 2.63 3 7 F7-52 A 62-8 6 T F7-54 7 T 2.63 3 7 T 2.63 NDD 7 F7-56 B 16-22 61 T 2.63 112 7 F7-57 A 37-29 52 T 2.63 4 7 F7-58 16-69 2 2.63 6 7 F7-65 88-7 10 T 2.63 16 7 F7-71 13-63 20.5 T T 2.63 4 7 F7-73 16-69 2 2.63 3 7 F7-86 62-8 8 T 2.63 112 7 F7-88 37-29 52.5 T P14 A 112-5 4.75 T 0.090 4.6 7 3.2 T 1.75 3.1, 3.35 2 P14 1.0 3.3 2 P14 A 111-13 3.3 L

AC U4 a -cae m = ~ito m Babcock G.Wilczx a McDermott comomy Lynchtweg Roemereh Center Lynchimeg, Virgin,ie 24506 1166 To J. F. CUVELIER - SPIS

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S.C. IPNAN - NUCLEAR MATERIALS, LRC

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  • RDO:86: 5046-04:01 GPUN Date Subl.

MAY 7, 1985 TMI-1 OTSG TUBE RETEST This lettee to cove < one customer and one s.abiect only.

SlNMARY Eddy current defect indications were recently observed in the unexpanded portion of a number of 0TSG tubes at TMI-1. As part of an investigation to determine their origin, fourteen sections of removed TMI-1 tubing in storage

- at the LRC were retrieved, eddy current tested, and inspected on the inner surface using fiber optics. The inner. surfaces of two tube sections were further examined using photography and metallography. Scattered darkened .

areas appearing as stains were visually observed on the surface. Metallo-graphic inspections showed some of these stained areas to contain patches of shallow intergranular attack (~0.008-inch maximum depth) and isolated pits

(~ 0.005-inch maximum depth).

Results showed no significant difference between eddy current signals observed during previous testing and those observed during this work. It could not be determined from this investigation whether the mechanism which caused damage to the tubes in situ at TMI-1 was active or inactive during the storage peri od.

DISTRIBUTION: Company Limited This information is freely available to all Company personnel. Written approval by sponsoring unit's R&D coordinator is required only if release outside of the Company is requested.

NPD-SPIS ARC LRC Bohn, LH Bhada, RK Ayers, PS Markert, W Davis, HH MD Fahland, FR Gmach, JA Sarver, LW Engelder, TC Southards, WT Hayner, G0 Gutzwiller, JE Hellman, SP CIC Library (2)

Holt, AE Latham, WM Post, RC Library (2) Stanek, LJ Zeh, TJ 4

B&W makes no warranty or representation, expressed or implied:

e with request to the accuracy, completeness, or usefulness of the f iformation contained in this report e that the use of any information, apparatus, method, or process disclosed in this report may not infrige privately owned rights. I B&W assumes no liability with respect to the use of, or for dam-ages resulting from the use of:

e any informaion, apparatus, method, or process disclosed in this report e experimental apparatus furnished wi. this report.

i

BABC0CK & WILC0X RDD:86:5046-04:01 PAGE 1

1.0 INTRODUCTION

In late 1984 and early 1985, in situ eddy current testing of the Three Mile Island Unit 1 (TMI-1) once-through steam generators-(0TSGs) revealed new defect indications in the unexpanded region of many tubes. These indications had not been observed during previous inspections performed immediately after the tube expansion operation.

This project was initiated to investigate possible origins of these new indications. Sections of tubes which had been removed from the OTSGs and were in storage at the Bebcock and Wilcox Lynchburg Research Center (LRC) were retrieved for re-examination. Laboratory eddy current testing, fiber optics and visual inspections of the tube inner surf aces, and ..etallography T were utilized in this examination, results of which are presented in this report.

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BABC0CK & WILCOX RDO:86: 5046'-04: 01 PAGE 2 2.0 METHODS AND RESULTS 2.1 Eddy Current Testing Personnel from both B&W and GPUN participated in an inspection using the same equipment and similar test parameters as that used during inspections performed in June 1982 at the LRC and in situ at TMI-1. A total of fourte:

(14) sections of sir (6) different peripheral tubes from the A-0TSG were examined using two (2) dif ferent probes. The 0.500-inch diameter annular differential probe (manufactured by B&W) was used at frequencies of 200, 400, 600, and 800 kHz. The 0.540-inch diameter annular differential probe (manufactured by Zetec) was used at 200, 400, and 800 kHz frequencies (all dif ferential) and 200 kHz absolute. The Zetec MIZ-12 system was used to drive the probes at the selected frequencies. The frequencies, phase angle, and gain settings used duplicated those used in the 1982 inspections and in situ at TMI-1. ,

Prior to inspecting the tube sections, the techniques were calibrated using the same standard as was used in 1982. The standard was rotated at four 90' increments, giving a total of four scans for each method. Using the 0.540-inch probe, the amplitude of the signal response to the 0.052-inch diameter through-wall hole in the calibration standard was set at 15 volts peak-to-peak (400 kHz). During calibration, the maximum amplitude variation was 15.3 to 14.6 volts using the 0.540-inch probe and 10 to 4.2 volts with the 0.500-inch probe. Since the standard was not rotated during the 1982 inspections and amplitude will vary depending on relative circumferential location of the defect, direct comparisons between voltage responses from one inspection to another should be avoided.

The inspection data were recorded on magnetic tape and later analyzed using the digital data analysis system (DDA-4). Table 1. lists results of the 1985

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and 1982 inspections performed at B&W. Two tube sections, A112-5 Piece 1 and A23-93 Piece 1, were not inspected at B&W in 1982. Therefore, results of

R00: 86: 5046-04:01 PAGE 3 BABC0CK & WILC0X inspections performed by Battelle and Conam in 1981 are listed for comparison.

No indications were observed in the 1985 inspection which were not observed previously. Slight differences in the axial location of indications exist between the two inspections and are attributed to different means of measuring location on the tube at which the indication was observed.

2.2 Fiber Optics Inspection Each tube section exhibiting eddy current-indication (s) was inspected on the inner surface using an 8 mm Olympus Fiberscope with a 90' head. The tube was rotated to permit inspection of the entire surface. Results were recorded on videotape while monitoring them on a high resolution CRT. A sunmary of observations made during the inspection is listed in Table 2. Results showed that an anomaly of some type, i.e. pits, stains, and/or cutter tool damage, was present at each location where an eddy current indication was observed.

2.3 Visual Inspections and Photography Two tube sections were selected for destructive examinations based on results of the nondestructive inspections. Piece 1 of tube A112-5 was selected since it contained multiple eddy current defect indications over a small length of the tube. Piece 1 of tube A111-13 was selected to investigate a small voltage indication. The sections were split longitudinally in half along pre-deter-mined axes using both a diamond saw and jeweler's saw. The appearance of the

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inner surf aces was documented at various magnifications between approximately 7x and 30x using the stereomicroscpoe and 35 mm color photography, while landmark areas were noted. Photomontages were assembled to reconstruct the tube sample appearance. Comments made during the visual inspections and from the photographs are listed in Tables 3 and 4. Selected photographs of the tube samples are shown in Figures 1 through 4. The following is a description of the samples.

BABC0CK & WILC0X RDO:86: 5046-04:01 PAGE 4 Tube A112-5 Piece 1 This 10-inch tube section was transversely cut at 7 inches and both pieces then split along the 120-300* axes. As noted in Table 3, the upper 6 inches of the sample contained numerous pits, cracks, and stains. Except for darker brown stained regions, the color of the inner surface was typical of that observed during the previous examinations (1,2). In many cases, cracks and scattered pits were associated with the darker brown stained regions, but many stains were observed without defects. The stains were observed in a variety of shapes, from single spots to large " patches" with branches in many directions. All cracks were circumferentially oriented and longitudinal sectioning had intersected nearly each one, so the crack lengths listed are approximate. The pits were approximately 0.005-inch or less in diameter.

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Tube A111-13 Piece 1  ;

I The upper 4 inches of this 22.6-inch long tube section was longitudinally split in half along the 0-180* axes. Table 4 lists the observations made from the A111-13 samples. The inner surfaces were relatively clean when compared to the A112-5 samples, i .e. very few stained regions and scattered pits. When pits were observed, they were also very small (0.005-inch maximum diameter) and located within stained regions. No cracks'were visible in the A111-13 tube samples. Figures 3 and 4 are typical photographs showing some of the minor anomalies present.

The inner surface of both sample halves from tube A111-13 was placed in tension in the hoop direction by placing the samples concave side down on a flat surface and applying a 185-pound load to the tube outer surface. This was done to determine whether any non-visible anomalies on the inner surf ace would open and become visible. The photographs of the samples after stressing showed no visible change in the appearance of the tube surface.

BABC0CK & WILC0X RDO:86: 5046-04:01 PAGE 5 2.4 Metallography Tables 5 and 6 contain details of the metallography performed during this investigation. Figures 5 and 10 are the cutting diagrams for the samples from tubes A112-5 and A111-13, respectively, which indicate specimen origination. The specimens are described below according to tube number.

Tube A112-5 Samples Four small half-ring specimens were sectioned from the region of the 300-120*

sample containing a " tree-like" stained and pitted region on the inner surface at 1 to 1.5 inches from the top of the piece. All four specimens were mounted together so that transverse edges could be examined. Three individual grind increments of approximately 0.005, 0.010 and 0.015-inch were taken into the specimens, with inspection and photography at each increment. Results showed that stained regions of each specimen corresponded to areas of superficial intergranular attack (IGA) of 10.001-inch in depth. In fact, this corrosion was barely distinguishable from the as-manufactured pickling corrosion on the inner surface. Typical photomicrographs of this observation are shown in Figure 6. A number of shallow pits and depressed areas were observed, examples of which are shown in Figures 7 and 8. Maximum observed depth of these regions was scaled to be 0.005-inch, or approximately 13 percent of the tube wall thickness. Maximum observed surface cpening or mouth of a pit was approximately 0.010-inch. One pit (shown 1.n Figure 8) had intergranular penetrations extending from its base. In all cases, the anomalies observed on these four specimens were adjacent to or within regions of superficial IGA.

A 0.145-inch long half-ring specimen was sectioned from an axially oriented stain containing pits in the 120-300* sample. Incremental grinding steps were also taken through this specimen, with inspection of the transverse edge at each increment. Again, the stained region corresponded to superficial IGA 10.001-inch in depth on the inner surface. A depressed region, possibly several overlapping pits, was observed at the location where a pit was observed during the visual inspections. Maximum observed depth of_this defect

BABC0CK & WILC0X RDO:86:5046-04:01 PAGE 6 was 0.002-inch. S lected photomicrographs of this specimen showing the depressed region and the superficial IGA are shown in Figure 9.

Tube A111-13 Two strip specimens were sectioned from 1 to 2 inches from the top and mounted longitudinally in attempt to intersect the single pits at 1.2 and 1.6 inches.

These specimens are shown in Figure 10 as specimens "A" and "B", respectively.

Successive grind increments were taken into both specimens as indicated in '

Table 6.

Nothing anomalous was observed on the inner surface of specimen "A". Figurs 11 is a typical photomicrograph of the inner surface and reveals the as-manufactured pickling corrosion observed.

Figure 12 contains photomicrographs which reveal the " patch" of IGA observed on the third and fourth grind increment of specimen "B". Maximum depth of the I IGA was determined to be 0.005-inch, with a mouth of 0.013-inch. Also on the fourth increment, an area of shallow surface corrosion (<0.001-inch deep) was observed at a location 0.040-inch down the tube from the IGA. A final grind increment of 0.013-inch revealed the typical tube inner surface appearance, with no anomalies.

Longitudinal specimens "A" and "B" were then removed from the metallographic mounts and reverse bent about a plane normal to the tube axis (inner surface in tension) to open any cracks present. Inspection of each specimen under the stereomicroscope revealed no cracks in specimen "A", while a circumferential crack did open at approximately 1.6 inches in specimen "B". The crack was approximately 0.135-inch long and intersected a cut edge (approximately the 70* axis). While the crack was not 100 percent through-wall, maximum depth was not determined. Figure 13 contains photographs of this crack.

a R00:86: 5046-04:01 PAGE 7 BABC0CK & WILC0X Specimen "C" shown in' Figure 10 was sectioned from 2.5 to 3.25 inches and 3

mounted so that a longitudinal edge could be viewed in the regions of pitting at 2.8 inches from the top. The first and second grind increments revealed a circumferentially oriented intergranular crack penetrating a mar.imum of 0.010-inch into the tubewall. Photomicrographs in Figure 14 stow this crack and the " cap" of material on the tube inner surface protuting inward toward the tube center. A single pit just above an area of superficial corrosion was observed on the third increment. The pit was appreximately 0.002-inch ceep on this plane of polish, which did not intersect the mouth of the pit. This indicates the pit was somewhat spherical in shape wi'h an overall diameter greater than it's mouth diameter. Photomicrographs of the specimen on the third and forth grind increments are shown in Figure .5. Tre fourth grinding increment revealed only very shallow superficial corrosion

(<0.001-inch deep), indicating the pit was less than 0.014-inch in diameter (most likely well less).

Strip specimens "D" and "E" shown in Figure 10 were reverse bent in the same fashion as were specimens "A" and "B". A circumferential crack opened at 1 inch from the top of specimen "D" and extended from the 180* cut edge approximately 0.240-inch toward the 270' axis. The photographs of this crack

-50wn in Figure 16 indicate it was less than 100 percent through-wall in mum depth, however maximum depth was not determined. No cracks were observed in specimen "E" after bending.

J

BABC0CK & WILC0X RDO:86: 5046-04: 01 PAGE 8 3.0 DISCUSSION Fourteen tube sections were re-eddy current inspected using similar parameters and the 0.500 and 0.540-inch probes during this project. As seen in Table 1 amazingly small differences exist between the depth estlmated and voltages of the indications detected during the present and previous eddy current inspec-tions. These differences are well within those expected due to process varia-tion and are deemed insignificant. With the differences between location of indication due to method of measurement, it must be concluded that no change occurred to the eddy current indications as a result of the tubes being in dry storage in plastic bags for several years.

Subsequent additional eddy current testing was performed at the LRC which utilized the more sensitive 8x1 probe. In addition to the crack indications detected in piece 1 of tubes A112-5 and A111-13 using the differential prot the 8x1 inspection detected more defect indications (results reported in a GPUN document). Destructive examination of these tube. sections during this I

project confirmed that the crack-like indications were caused by circumfer-ential cracks and/or patches of IGA. Since these tube sections were not destructively examined during the previous tube examinations (1,2), it could not be determined whether the dry storage conditions played any role in form-ing the currently observed defects. It seems doubtful however, that any growth or propagation had occurred since no change occurred to the eddy cur-rent indications.

Inadditiontothecracks,manyisolatedandclusteredpitswerepresent within stained areas in tube A112-5. These pits were very shallow

(<0.005-inch in depth) and insignificant when compared to the severe pitting corrosion which has been observed in steam generator tubing removed from other nuclear plants.(3)

Due to the small volume of material removed, it is doubtful that the pits present in the TMI-1 tubes would be observed'as defects using conventional eddy current testing methods. Determining the origin of the pits and stains in the TMI-1 tubes was not within the scope of this project.

RDO:86: 5046-04: 01 PAGE 9 BABC0CK & WILC0X

4.0 CONCLUSION

S The following have been concluded based on the results of this examination of TMI-1 OTSG tube sections:

a Using the 0.500 and 0.540-inch differential probes, no increase in size of the existing eddy current defect indications in the TMI-1 A-0TSG peripheral tubes was observed as a result of being in dry storage for several years. Also, no defect indications were observed which had not been observed during the 1982 inspections, e Crack-like defect indications were caused by the presence of circumferential cracks and/or patches of IGA on the tube inner surface.

I R00:86:5046-04:01 PAGE 10 BABC0CK & WILCOX

5.0 REFERENCES

1. M.A. Rigdon and E.B.S. Pardue. " Evaluation of Tube Samples from TMI-1."

Babcock and Wilcox Document Number 77-1135317, 1981.

2. S.C. Inman. " Examination Of 0TSG Tubes from TMI-1 Third Pulling Sequence

- Final Report." Babcock and Wilcox R00:83:5068-03:03, December 1982.

3. S.C. Inman. " Examination of Steam Generator Tube Sections from the Millstone Point Unit 2 Nuclear Power Plant." Project 5304-6, Electric Power Research Institute, Palo Alto, California (to be published).

t

T cz3 n

R n

so E*

IABLE I g p 100Y CultR(h! IE51thG RESULTS n

1995------------------- o M

--.----....----------.--1932----------------------

P r obe - ------

Probe--------

82 - 85

-l catlon og 0.500* 0.540' Comparison 0*S00' 0*$4O' Ind kation Depth / Voltage (1/V) Cannents Antal L*Ii*" "f Septh/ Voltage (1/V) Comnents 015G Yube 10 Ptece e loc ation 2 Ind 6 cat ion _.3 h00 NGO N ltiple Dents no Change

- targe Dent 31 38 1.5 (Comments) he Change A 13 63 ^ 3 4.8 86/2.2 84/ 3.2 Indication on 90-100/1.5 - 50 Defect 00 Plane 4.3 - 12.3 4.3 ho Change A 112 9 1 2.5 62/4.6 78/2.4 ladication on 3.0 90-100/1.4 90-100/2 3 10 DefMt 00 Plane A 24 94 3 13.3 - 19.8 80 0 Itultiple Gents les Change N00 he Change N00 -

$100 000 8 41.8 - 48.9 N00 -

NGO 3 Selges no Change 9 48.9 - 55.8 hu0 :x3 NGO 10 55.0 - 67.8 Initially toestified (near h00 89/0.8 Possible Oe-fect, 10 Plane no Change @

1 2 - 24.6 1.0 -/0.5 -

using 00 pencil probe top) No Change ao a 111 13 N00 000 @

No Change **

h00 NDO 10 0 3 50.7 - 57.5 huo -

800 abo he Change 4 16.3 - 89.0 hu0 -

800 h00 small Otng he Change o F E51.3 - 576.4 no Change &

800 0 -

h00 80 0 2 Dents @

  • 8 176.4 - 201.6 NUD - 8 204.6 - 213.8 no Change 9
1. 8 95/1 -

2.0 92/3.) 81/2.7 Indications on 00 Plane, h A 112 5 4 1 2 - 12 87/5.1 stultiple Small fio change

3. 8 85/1.8 y 3.1 95/2 -

Indications hot Reported Ito Change 6.2 62/0.7 79/2.8

5. 8 95/1 No Change (Comnents) 10 0 Possible In-
0. 6 alof ' -

4tcation 80 ear A 23 93 I I 2 -12 Top of Tube i M iphen ladicates not inspected using that techasque NGO - No Detectaele Otscontinettes 2 Inches f rom 015G UTS Prnaary f ace 3 laches f rom tw of tube p6Ee 4 1962 results f ra Conaa inspection g 1962 results f rom Battelle inspection 6 Voltage not available M

b W

PAGE 12 RDO:86: 5046-04:01 BABC0CK & WILC0X TABLE 2 FIBER OPTICS INSPECTION

SUMMARY

Axial I Location Remarks Tube Piece Orientation A13-63 3 0* 6 Stained area 180* 1.5 Scattered pits, cutter tool damage 2-2.5 Scattered pits 3-3.5 Possible pits (Scattered pits along length of section) 240* 1.5-2 Possible pits, cutter tool damage 4.5 Scattered pits (Scattered pits along length of section) 300* 4-4.5 Possible pits 0* 6.5-7 Possible pits A112-9 1 180* 4 Stained areas 270* 4 Axially oriented staining 3 180* 2.25 Possible raised area .

A24-94 Pits ,

2.75 3 Stained areas 270* 0.5-1 Pits 2-2.5 Pits 2.25 Possible raised area 2.75 Pits 90* 1.75 Single pit A111-13 1 Possible pits, stains 180* 1 Pits, stains 270* 1 340* 1 Pits, stains 30* 2 Possible pits, stains A112-5 1 Pits and stains 4-4.5 90* 2.5 Pits

' 4-4.5 Pits and stains 190* 5.75-6 Stains 260-360* 4.5 Cutter tool damage 8-8.5 Pits and spots 270*

350' 3.75 Pits 0* 0.75 Pits A23-93 1 Pits 200-270* 0.5-0.75 250* 5.5 Stains I Inches from top of piece i

RDD:86:5046-04:01 PAGE 13 BABC0CK & WILCOX TABLE 3 VISUAL INSPECTION RESULTS FOR TUBE SAMPLE A112-5 Axial Location, in. from top of tube section Comments 0.05-0.6 Axial lines of stain containing pits 0-0.2 Tube removal damage 0-0.8 Serpentine stains 0.35-0.9 Patch of stain III 0.55 Ci rcumferential crack, 0.258-inch 0.64 Pits within stains 0.75 Circumferential crack, 0.144-inch (2) 1.0-1.6 Tree-like stain containing pits 1.1 Ci rcumferential crack, 0.092-inch 1.4 Circumferential crack, 0.210-inch 1.5 Pits within stains )

1.6 Circumferential Circumferential crack,crack. 0.123-inch ((2) 0.060-inch ,

1.7 1

pits within stains 1.8 Ci rcumferential crack, 0.072-inch ((3) 1.9 Circumferential crack, 0.196-inch (;)}

2. 0 Ci rcumferential crack, 0.185-inch 2.2-3.6 Axial line of stain containing numerous single pits Circumferential crack, 0.143-inch (g) 2.3 III Circumferential crack, 0.205-inch II) 2.6 3.2 Circumferential crack, 0.263-inch 3.6 Circumferential crack, 0.232-inch 4.0 Circumferential crack, 0.252-inch 4.3 Pits within stains 4.6-5.9 Pits within stains
4. 9 Patch of stain 5.4 Circumferential crack, 0.255-inch (g) 5.4-5.9 Pits within stains 7.4-9.3 Tube removal damage 8.0-8.5 Pits within stains III Crack observed on both halves after sectioning; crack length obtained by adding dimensions from both halves.

(2) Crack observed on 120-300* half.

I Crack observed on 300-120' half.

BABC0CK & WILCOX RDO:86:5046-04:01 PAGE 14 TABLE 4 ,

VISUAL IhSPECTION RESULTS FOR TtBE SAMPLE A111-13 l

-Axial Location, in, from top of tube section Comnents 0-1.0 Tube removal mandrel marks 0.84 Isolated pits 1.0 Isolated pits 1.29 Isolated pits 1.6 Stains containing pits 2.88 Stains containing pits 3.5-3.8 Scattered single pits 4

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R00:86: 5046-04:01 PAGE 15 BABC0CK & WILC0X TABLE 5 METALL0 GRAPHY RESULTS FOR TUBE A112-5 Specimen Axial g Designatjon- Grind 3

Half, cw Location Type Increment Observations 300-120* 1-1.2 Al-T ~ 0.005 Surface IGA in stains,

<0.001" max. depth

~ 0.010 Surface IGA in stains,

<0.001" max. depth

~0.015 Surface IGA in stains,

<0.001" max. depth 1.2-1.3 A2-T ~0.005 Surf ace IGA in stains ,

<0.001" max. depth; intersucted crack at 1.2"

~0.010 Surface IGA in stains,

<0.001" max. depth

~ 0. 015 Two single pits, 0.002" max.

depth; surface IGA adjacent -

to cits, <0.001" max. depth 1.3-1.4 A3-T ~0.005 Two adjacent pits, 0.001" mar. depth; surface IGA adjacent to pits, <0.001" max. depth

~ 0.010 Surface IGA in stains,

<0.001" max. depth

,w ~0.015 Single pit, 0.005" max.

depth, IGA at base of pit; surface IGA adjacent to pit 1.4-1.5 A4-T ~0.005 Surface IGA in stains,

<0.001" max. depth

~ 0.010 Surface IGA in stains,

<0.001" max. depth

~0.015 Surface general corrosion, 0.002" max. depth; two single pits, 0.002" max.

depth fMeasuredfromtopofpiece 3

T: Transverse views Incremental amount of material removed, in inches

RDO:86:5046-04:01 PAGE 16 BABC0CK & WILC0X TABLE 5, cont'd.

METALL0 GRAPHY RESULTS FOR TUDE A112-5 Specimen Axial y Designatjon- Grind 3 Half, cw Location Type Increment Observations 120*-300* 2 7/16- B-T 0.035 Surface IGA in stain,

<0.001" max. depth 2 3/4 Several overlapping pits, 0.005 0.002" max. depth; surface IGA in stain adjacent to pits, <0.001" max. depth 0.002 Surface IGA in stain,

<0.001" max. depth 0.014 Surface IGA in stain,

<0.001" max. depth 0.012 Surface IGA in stain,

<0.001" max. depth; intersected crack at 2.3" i

fMaasuredfromtopofpiece 7: Transverse views 3 Incremental amount of material removed, in inches

BABCOCK & WILCOX RDO:86:5046-04: 01 PAGE 17 TABLE 6 METALL0 GRAPHY RESULTS FOR TUBE A111-13 Specimen Axial g Designat{on Grind 3 Half, cw location Type Increment Observations 0-180' 1-2 A-L (1.2") 0.019" Typical ID surf ace appearance 0.023" Typical ID surface appearance 0.015" Typical 10 surface appearance 1-2 B-L (1.6") 0.013" Typical ID surf ace appearance 0.014" Typical 10 surface appearance 0.011" " Patch" of IGA, 0.005" max.

depth, 0.013" mouth 0.0059 " Patch" of IGA, 0.005" max.

depth. 0.010 mouth; surface corrosion 0.040" below IGA,

<0.001-inch deep 0.0117 Typical ID surface appearance 2 1/2 - C-L (2.8") 0.093 IG Crack, 0.010" max. depth; 3 1/4 surface IGA adjacent to crack,

<0.001" max. depth 0.023" " Paten" of IGA, 0.008" max.

deptn, 0.005" mouth; surf ace IGA adjacent to crack, 0.002" max. depth 0.014" Single pit, 0.002" max. depth, 0.002" mouth; surface corrosion 0.030" below pit, 0.002" max.

depth; surface IGA between pit and general corrosion, 0.003" max. deptn 0.013" Surf ace general corrosion, 0.002" max. depth i

fMeasuredfromtopofpiece 3

L: Longitudinal views Incremental amount of material removed, in inches

BABC0CK & WILC0X R00: 86: 5046-04: 01 PAGE 18 4

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RDO: 36: 5046-04: 01 PAGE 21 BABC0CK & WILC0X g r.7 K' ~. . ., .u ,5

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BABC0CK & WILC0X R00:86: 5046-04: 01 PAGE 22 A 112-5 Piece i 12 0 ' 300* 120' UTS-2 g 4 1.0" 4

- A 0. 5 "

2. 5,, ,g Specimen List 9

B A: 4 Transverse specimens ,

9 through tree-like stain 7" 01- and pits B: Transverse speciren through pit string

(

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, 3" UTS -12" "

l Figure 5. Section Diagram for Tube 112-5 Sample

BABC0CK & WILC0X RDO: 86: 5046-04: 01 PAGE 23

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i Specimen A3 - Grind 1 Typical ID

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Specimen A1 - Grind 1 Shallow IGA Figure 6. Transverse Photomicrographs Tnrough Tree-like Stain in Tube 112-5 Specimens

- - - , - - - . - - - - - - , - , _ , - - - - - - - , - - - - - - - - , ~ - -,---w-,

l R00: 86: 5046-04: 01 PAGri 24

BABC0CK & WILC0X l

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in Tube 112-5 Specimens d

i

h h a l BABCGCK & WII.00X RDD: 86: 5046-04: 01 PAGE 25

.A___._._.______'

O.01-inch l I i

Specimen A3 - Grind 3 Single Pit

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R00:86: 5046-04: 01 PAGE 26 BABC0CK & WILC0X r L

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l l

RDD: 86: 5046-04: 01 PAGE 27 BABC0CK & WILC0X A. lli-13 Piece i O' 18 0' 360' I I I 4 Il Specimen List A B A: Longitudinal Specimen to I" examine pit at 1.2", reverse bend n '

D E B: Longitudinal specimen to 4 examine pit at 1.6", reverse.

0. 5,, bend ll C: Longitudinal specimen to

,, examine pits at 2.8" 4 D&E: Reverse bend specimens

-t l

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H Figure 10. Section Diagram for Tube 111-13 Sample

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RDD: 86: 5046-04: 01 PAGE 28 BABC0CK & WILC0X 1

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BABC0CK & WILC0X RDD: 86: 5046-04: 01 PAGE 29

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PAGE 30 BABC0CK & WILCOX RDO: 86: 5046-04: 01 l

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RDO: 86: 5046-04: 01 PAGE 31 BABC0CK & WILC0X l

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l RDO: 86: 5046-04: 01 PAGE 32 l

BABC0CK & WILCOX i

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RDO:86: 5046-04: 01 PAGE 33 BABC0CK & WILC0X s .k '.1' i

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Figure 16. Photographs of Tube 111-13 Specimen 0 - Af ter Bend

- _ _ _ _ .

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