ML070600237

IR 0553792-02, Drywell Structural Integrity Basis from 1R21 Inspections (Draft Before PORC Review)

ML070600237
Person / Time
Site:	Oyster Creek
Issue date:	10/24/2006
From:	Stone L - No Known Affiliation
To:	Office of Nuclear Reactor Regulation
References
IR-05-002
Download: ML070600237 (29)

Text

J IR 0553792-02, Drywell Structural Integrity Basis from 1R21 Inspections Reasons for Evaluation/Scope The purpose of this Technical Evaluation is to present current and projected (until 1R22) margin in Drywell Vessel Thicknesses and the bases to further confirm that the drywell structural integrity continues to maintain design basis requirements as established in references 1 through 3. The intent of this evaluation is to demonstrate that the Drywell Vessel thicknesses are adequate to satisfy current licensing and design bases requirements.

This Technical Evaluation was developed in accordance with CC-AA-309-101, Revision 7.

A prejob brief for this Technical Evaluation was performed by Howie Ray in accordance with HU-AA-1212 Rev 1. The risk rank of this Technical Evaluation was concluded to be a 4, since the acceptance criteria have already been established and Approved through existing design analysis.

Therefore a third party review is not required.

Background

In the 1R21 Outage a series of UT thickness measurements were performed of various elevations of the Drywell Vessel in accordance with specification OC-IS -328277-004. The purpose of these UT inspections is to measure corrosion rates of the Drywell Vessel and further confirm that the vessel meets the design basis.

This is accomplished by inspecting the same locations over time.

In the mid 1980s a s w e y was performed of the Drywell Vessel at the Sandbed elevation (1 1 3).

As a minimum at least one inspection location (also referred to as a grid) was selected in each of the 10 Drywell Bays and permanently marked. These were then selected for repeat inspection and entered into the Drywell Thickness Monitoring Program.

UT Inspection of locations with the most thinning consisted of obtaining 49 individual UT thickness readings in a 7 by 7 pattern spaced on 1 inch centers. These measurements were taken using a stainless steel template. The template was designed to ensure that the 7 by 7 grid is located in the same area with repeatability of a 1/16.

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The program then performed UT inspections over time at these same locations from 1987 to 1996.

The corrosion rates were developed using a standard regression analysis and establishment of the 95% confidence intervals to capture increasing variance depending on the projection of ongoing corrosion and the number of inspections. This methodology is based on the following references:

Applied Regression Analysis, Second Edition, N.R. Draper & H. Smith, John Wiley and Sons 1981 Statistical Concept and Methods, G.K. Bhattacharyya & R.A. Johnson, John Wiley and Sons 1977, I

IR 553792 Assignment 02 1

3) Experimental Statistics, Mary Gobbons Natrella, John Wiley and Sons 1966 (Reprint

4) Fundamental Concepts in the Design of Experiments, Charles C Hicks, Saunders College National Bureau of Standards Handbook 91)

Publishing, Fort Worth, 1982 Each time UT inspections are performed the distribution of the individual readings is checked to confirm the original distribution evaluation.

Inspections of the Drywell above the sandbed have been performed up to 2006. Corrosion rates have been calculated in calculation C-1302-187-E310-037 Reyision 2 and ECR 05-00575.

Corrosion in the sand bed region was addressed by removing sand, water, and corrosion byproduct in the sanhbed and applying a coating on the exterior of the vessel in 1992.

Comparison of UT inspections performed in 1992 and 1994 as documented in C-1302-187-5300-030 shows that the sandbed region continues to meet design basis requirements.

This Technical Evaluation will compare the 2006 UT inspection data to these earlier calculations to hrther confirm conclusion that the drywell vessel continues to meet design basis.

Detailed Evaluation Methodology C-1302-187-E310-037 Revision 2 and C-1302-187-5300-030 identify the locations which are the most critical with respect to thinning (see table 1). These are located at five different elevations 1 1 3, 50 2, 51 lo, 60 lo, and 87 5.

These calculations developed corrosion rate projections for these critical locations. The mean of the 2006 inspection of the same critical locations plotted on the earlier projections to determine if those projections are still valid and bound the current inspection results.

Elevation 1 1 3 Refer to the data in attachment 3 and the projection curve for location 19A in attachment 2.

Calculation C-1302-187-5300-030 identified location 19A as the most critical since it was the thinnest area in the sandbed. However the calculation concluded with 95% confidence that this location and the other sandbed region locations were not experiencing corrosion. Figure 1 provides a trend of the mean values for this location. Figure 1 also provides curves showing the calculated standard error of plus or minus 0.0034 inches for the means. The 2006 mean is also plotted on figure 1 and shows that this value is well within the standard error band.

Table 1 provides a breakdown of the mean thickness measured in 2006 and associated current margin.

IR 553792 Assignment 02 2

Elevation 50 2 I

Refer to the data in attachment 3 and the projection curves for locations 5-5 and 13-23 in attachment 2.

The 2004 calculation identified locations 5-5HI and 15-23HI as the most critical since they were the thinnest at this elevation. The calculation concluded that these locations are experiencing corrosion rates of 0.0003 and 0.0004 inches per year with 95% confidence. Figure 2 and Figure 3, provide trends of the means of data collected from 1987 through 2004 for these locations taken from calculation C-1302-187-E310-037 Revision 2. The 2006 means for each location are plotted on these figures. These show that the 2006 means are consistent with and are bounded by the 2004 projections. Therefore the margins and projections from 2004 remain valid and bounding. Table 1 provides the means and margin calculated in 2004.

I Table 1 provides a breakdown of the mean thickness measured in 2004 and associated cbrrent margin for these two locations.

I Elevation 5 1 10 Refer to the data in attachment 3 and the projection curve for location 13-32 in attachment 2.

The 2004 calculation identified location 13-32 as the most critical since it was the thinnest at this elevation. However the calculation concluded with 95% confidence that the location was not experiencing corrosion. Figure 4 provides a trend of the means of data collected from 1987 through 2004 for this location taken from calculation C-1302-187-E3 10-037 Revision 2. The 2006 mean for this location is plotted on this figure. Figure 4 also provides curves showing the 2004 calculated standard error of -/+ 0.0053 inches for the data from 1987 to 2004. The 2006 mean is well within the 2004 standard error band.

This shows that the 2006 mean is consistent with and bounded by the 2004 projection, which concluded that this location is not corroding. Therefore the margin and projection from 2004 remains valid and bounding. Table 1 provides the means and margin calculated in 2004.

Table 1 provides a breakdown of the mean thickness measured in 2004 and associated current margin.

I Elevation 60 10 Refer to the data in attachment 3 and the projection curve for location 5-22 in attachment 2.

The 2004calculation identified location 5-22 as the most critical since it was the thinnest at this elevation. However the calculation concluded with 95% confidence that the location was not experiencing corrosion. Figure 5 provides a trend of the means of data collected from 1992 through 2004 for these locations taken from calculation C-1302-187-E310-037 Revision 2. The IR 553792 Assignment 02 3

2006 mean for this location is plotted on this figure and shows that this value has virtually not changed since 2004.

Figure 4 also provides curves showing the 2004 calculated standard error of the data from 1987 to 2004. The 2006 mean is well within the 2004 standard error band.

Table 1 provides a breakdown of the mean thickness measured in 2004 and associated current margin Elevation 87 5 Refer to the data in attachment 3 and the projection curve for location 9-20 in attachment 2.

The 2004 calculation identified location 9-20 as the most critical since it was the thinnest at this elevation. The calculation concluded that this location was experiencing a corrosion rate of 0.00075 inches, per year with 95% confidence. Figure 6 provides the trend of the means of data collected from 1987 through 2004 for these locations taken from calculation C-1302-1 87-E3 10-037 Revision 2. The 2006 mean for this location is plotted on this figure. This shows that the 2006 mean is consistent with and is bounded by the 2004 projection. Therefore the margin and projection from 2004 remain valid and bounding. Table 1 provides the means and margin calculated in 2004.

Table 1 in attachment 1 provides a breakdown of the mean thickness measured in 2004 and associated current margin for these two locations.

Bay 15 Grid at Elevation 71 6 In 1 R2 1, Oyster Creek performed first time inspections of two 6 by 6 areas above the transition weld at elevation 71 6. The results of the 6 by 6 area in bay 15 showed several local readings less than the inspection specification acceptance criteria (ref. 4). The intent of the criteria in the specification was to provide a low threshold for inspection results so that unexpected readings would be evaluated. As a result IR 00556049 was issued. Review of the inspection results showed that the thinnest local reading was 0.449 inches.

The inspection specification criteria were purposefully set well above the design basis criteria. The minimum required design basis local thickness for this elevation is 0.300 inches (reference 2).

Therefore the as found thickness at this location meets the design basis requirements. In addition even when assuming a 1 mil per year corrosion rate, this location will continue to meet design basis until well past 2008. Comparison of this new location to an existing monitored location that has been determined to be the most critical for the plates at this elevation (location 9-20) shows that the projections for the previously monitored location are bounding (refer to attachment 3 page 11).

Bay 17 Grid at Elevation 23 76 In 1R21 Oyster Creek performed first time inspections of two 6 by 6 areas above the transition weld at elevation 23 6. The results of the 6 by 6 area in bay 17 showed several local readings IR 553792 Assignment 02 4

less than the inspection specification acceptance criteria (ref. 4). The intent of the criteria in the specification was to provide a low threshold for the inspection results so that unexpected readings would be evaluated. As a result IR 00548459 was issued. Review of the inspection results showed that the thinnest local reading was 0.628 inches.

The inspection specification criteria were purposefully set well above the design basis criteria. The minimum required design basis local thickness for this elevation is 0.360 inches (reference 23.

Therefore the as found thickness at this location meets the design basis requirements. In additiori, even when assuming a 1 mil per year corrosion rate, this location will continue to meet design basis until well past 2008. Comparison of this new location to an existing monitored location that has been determined to be the most critical for the plates at this elevation (location 15-23) shows that the projections for the previously monitored location are bounding (refer to attachment 3 page 14).

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Conclusions I

Table 1 demonstrates that current and projected margin in critical Drywell Vessel locations based on the comparison of recently obtained 2006 UT data and previously approved calculations remain adequate to continue to satisfy design bases requirements until 1R22. Comparison of the 2006 data to previously approved calculations, demonstrates that the conclusions in the previous calculations are still bounding the current data.

I References

1) C-1302-1 87-E3 10-037 Revision 1

3) C-1302-187-5300-030 Revision 1

4) Specification IS-328227-004 Rev. 13

2) ECR 05-00575 Attachments

1) Margin Table - 1 page

2) Review of 2006 means value to previous projections - 6 pages

3) Drywell UT Inspection Data - 16 pages IR 553792 Assignment 02 5

Prepared by Pete Tamburro I have performed an independent technical review of this technical evaluation in accordance with Section 413 of CC-AA-309-101, Revision 7. I have confirmed the correctness of the inputs, mathematics, and outputs. I have verified the methodology and compliance with design bases criteria are appropriate. The results accomplish the stated purpose.

Independent Review By Frank Stulb Manager Comments:

This technical evaluation was prepared and reviewed by qualiked personnel to pro ride a summar]

of the 1 R2 1 Drywell Inspection results performed in 2006. The conclusions demonstrate that the structural' integrity of the drywell shell, based on its measured thickness at representative locations, remains acceptable based on the previously approved methodologies and acceptance criteria.

Date: 11/06/06 Approved for Use: Ray, F.H. 11/6/2006.

I IR 553792 Assignment 02 6

Plate with Inches) 11 3 (1.1 54) 50 2 (0.770) 50 2 (0.770) 51 10 (0.772) 60 10 (0.722) 87 5 (0.640)

Summary of Oyster Creek Drywell Corrosion Monitoring Program Controlling Locations 19A Bay 5 Location Bay 15 Location Bay 13 Location 32 Lo Bay5 Location 22 Bay 9 location 20 5-HI 23-HI 0.7573 0.6872 0.6928 Measur ement (inches) 10/2004 10/2004 10/2004 When 0.6123 1 10/2004 Criteria 1 Margin in 2006 0.736 0.541 0.541 0.518 0.518 0.452 0.0706 0.2 146 0.2 163 0.1692 0.1748 0.1603 Percent 9.6%

39.7%

40%

32.7%

33.7%

3 5.4%

0 f Measured Corrosion Rate.

Inches/

year None 0.0003 0.0004 None None 0.00075 D

L Preliminary Projected margin in 2029 based on 95%

confidence interval around the corrosion rate 9.6%

36.5%

36.4%

32.7%

33.7%

33.6% -

Reference C-1302-187-5300-030 C-1302-1 87-E3 10-037 Rev 2

C-1302-187-E310-037 Rev 2

C-1302-1 87-E3 10-037 Rev 2

C-1302-187-E3 10-037 Rev 2

C-1302-187-E3 10-037 Rev 2

AmerGen Calculation Sheet Appendix 10 System No.

Sheet No.

Subject:

Calc. No.

Rev. No.

187 11 of 15 Drywell Corrosion C-l301-187-E31 O--

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MSR F actaul :=E CI :=0.05 F critical := qF( 1 - a, DegreeFree reg, DegreeFree ss)

F actaul F ratio I F critical 8 -

-3 Fratio = 1.715010 Therefore the curve fit of the means does not have a slope and the grandmean is an accurate measure of the thickness at this location i :=O.. Total 1

lWand measuredi := mean(y measured)

'Band measured := Stdev(p measured)

GrandStandad error,.-._ 'Band measured i-The minimum required thickness at this elevation is Tmin-gen SB :=736 (Ref. Calc. SE-000243-002) 1 Plot of the grand mean and the actual means over time Mrmd measured Tminxen SB

'g medown

'g meup -

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I X

~...................................................................................................................................................

x\\

t P 1

1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 Dates

AmerGen Calculation Sheet Bay 5 Area 5 f

maK( upper ) + 30 r

Subject:

Drywell Corrosion I

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I oC4 230 6 sc$

&=4 f

Q-------------O------------..............................................................

rco

-#w v

o n

-c upperf :=Thick predictf..

Appendix 2 System No.

Sheet No.

Calc. No.

I C-l302-187-E3lO-037 2

)

187 A2-27of 32 I

z (year predictf-Thick actualmean) sum lowerf :=Thick predictf...

year predictf-Thick actualmean sum General area Tmin for this elevation in the Drywell Tmin-gen I :=541 f

(Ref. Calc. SE-000243-002) m = -0.246 700 Thick predict upper lower 650 measured 0

Tminsen 5 1 50 600

AmerGen Calculation Sheet Thick highpredict '0° Fhigh measured D O 0 lower upper Tminxen 5 1 650 600 00 550 Bay 15 Area 23

Subject:

Drywell Corrosion For the thicker points Appendix 4 Sheet No.

C-l301-187-E310-037 187 A4-28of 32 2

(year predictf-Thick actualmean) sum lowerf := Thick highpredictf...

.Standard higherror' sum I

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Appendix 5 Sheet No.

AmerGen Calculation Sheet Bay 13 Area 32

Subject:

Drywell Corrosion A5 -24 Of 31 Standard error mean(cr1ow measured) = 5.291 690 plow measured 685 Og medown 672 67(

X X

>)<..X X

X X

1 I

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1990 1995 2000 2005 Dates

Appendix 6 AmerGen Calculation Sheet Bay 1 Area 50-22 r

Subject:

Drywell Corrosion

.-_c-----

Sheet No.

C-l301-187-E310-037 A6-120f 16 720 710 F measured xxx 700 rad measured Og medown Og meup 690 680 670 ~

Standard error I

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I ri3-11 L O O C X

mecr G P I X

X a

X X

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mean(' measured) = 11.865 j-mean(' measured)

'g medown :=Wand measured - I

Appendix 7 AmerGen Calculation Sheet Bay 9 Area 20

Subject:

System No.

Sheet No.

Drywell Corrosion 187 A7-23 of 23 The minimum requi (Ref. Calc. SE-000243-002)

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i m = -0.754 Location Curve Fit Projected to Plant End Of Life measured 0

TminJen 86 -

00 500.

'Ikick predict I

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I 2010 2015 2020 2025 2030 2030 1985 1990 1995 2000 2005 422 I 1.985403 year predict. Year predict, Year predict9Dafes I Year predict, 2006.8 year predictl2 = 2.009.10 3 Thick

= 604.1 15 Therefore the regression model shows that even at the lower 95% confidence band this location will not corrode to below Drywell Vessel Minimum required thickness by the plant end of life.

No Pits have been identified for this location

4 Template aligned to V Stamps.

COMMENTS: File Specific Comments located to right of readings.

Location ID 11C: The following template holes were painted onto the plate using the template. The readings were then taken with the template removed. This was done due to the Drywell Vent Attachment weld obstructing the template. Row 1 A through G, Row 2 A through C, Row 7 C through 0.

Thickness readings taken at holes located in template.

ST3772 0 - 0 2, v

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A B

C D

E F

G 1oroooooo 0 0 0 0 2oj818 3

0 0 0 0 0 1 4 0 0 0 o o o o 5 0 0 0 0 0 0 0

~ 0 0 0 0 0 0 0 7

0 o o o o o o

+-s-

+---------a I Reviewed by: Lee Stone Level II Date 1011 8/2008

14.-76 4b Level II Date 1011 812006 Level II Date 1011 8/2008 Level II Date loll 8/2006

General Electric File Name:

NIA Refueling Outage - 11 R21 Oyster Creek Ultrasonic Thickness Measurement Date:

1011812008 UT Procedure:

ER-AA-335404 SpeCifiCatiOn:

18328227-004 Data Sheet Page 3 of 15 Core Plug located at DO4, w5, and G04.

%$qf 10 06 Level II Date 1011 8/2006 Level II Date 1011 812006 Level II Date 1011 8/2006 Examined by Matt Wilson

General Electric File Name:

NIA Refueling Outage - 11 R21 Oyster Creek Ultrasonic Thickness Measurement Date:

1011812006 UT Proced~m: ER-AA Specifiption:

15328227-0011 Data Sheet Page 4 of IS I

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I HM' /O.24-06 Level II Date 10/18/2006 Level II Date loll 8M006 Examined by Matt Wilson Examined by Leslie Richter Reviewed by: L e e Stone z

Level II Date 1 011 8/2006

4 ieneral Electric vster Creek ieheling outage - 11~21 Page 5 of 15 4

I File Name:

NIA UT Pn>ced~~: ER-AA-335004 Ultrasonic Thickness Measurement Date:

10~18noo6 Specification:

18328227-004 Data Sheet

[

A B

I C

1 11.146 1.148 I 1.148 D

E F

I G

1.149 1.144 1.128 I 1.134 Location ID 13C Bay 13 Elev. I 11'3" Examined by Matt Wilson Level II Date 1 011 812006 Reviewed by: Lee Stone Level It Date 1011 812006 Examined by Leslie Richter Level II Date 1011 812006 Calibration Check: 13:M 1 Tscr.

I AVO.

.628 I 1.142 Level II Date 1 011 812006 Reviewed by: Lee Stone Level It Date 1011 812006 Examined by Leslie Richter Level II Date 1011 812006 Location Ir) 1 SA I

A B

I C 1

11.180 1.129 1 1.136 Bay 15 Elev.

Callbratlon Check 14:OO I D

E F

0 1.129 1.146 1.077 1.049

Ultrasonic Thickness Measurement Data Sheet IDamping:

ct I

NIA Template aligned to V Stamps.

Thickness readings taken at holes located in template.

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A B

C D

E F

G 1oroooooo 0 0 0 0 3

0

~ 0 0 0 0 0 0 0 6

0 0 0 0 0 0 0

'Oi2,g 0 0 0 0 '

4 0 0 0 0 0 0 0 '=

7 0 0 0 0 0 0 0 I

+-e-wM&L L @ / 0 - t 4 - ~ 0 Reviewed by: Lee Stone Level II Date lOl23l2006

Y Ultrasonic Thickness Measurement Data Sheet Reject:

Filter.

Template aligned to V Stamps.

Thickness readings taken at holes A

B C

D E

F G

~ o r o 0 0 0 0 0 d Q 9 0 0 0 0 L

1 located in template.

e COMMENTS:

Readings found below the minimum acceptance criteria, see page 2 (50 - 22).

L S

• w?o( &e i d - Z J - 0 6 3 0 0 1 0 0 0 0 0 Reviewed by: Lee Stone Level ll Date 10/23/2006

General Electric File Name:

Date:

Grid Procedure:

Oyster Creek Ultrasonic Thickness Measurement Refueling Outage - 11 R21 Data Sheet UT Pr~ced~re:

Dsnn 7 nf I7 I

wM&L L

z r

/i3-zq-ccp Examined by Level II Date 10/23/2006 Examined by Level II Date 10/23/2006 Reviewed by:

Level I1 Date 10/23QOO6 NIA 10/18/2006 ER-AA-335001 18328227-004

4 i

- L 1 General Electric File Name:

FUA Oyster Creek UI trason ic Thickness Measurement Date:

10118/2006 Data Sheet Coarse Range:

2.0" 14:30 I

See Data I

See Data I

1750 Delay Calib:

MA Thermometer:

246534 I

Comp.Temp:

72' IBiock Temp:

79" Range Calib:

NIA WIO Number.

R2091258 I

Coarse Delay:

NIA Calibrated h p

Range =

0.300" Inches to 1.500 Inches I

Instrument Freq.

N/A Total Crew Dose Drywell Containment Vessel Thickness Examination.

Gain:

58 db 20.2 mr Internal UT inspections.

Damping:

NIA Reject NIA Filter:

NIA l

Thickness readings taken at holes 3 0 0 0 0 0 0 0 I

0 0 0 O o 0 1 0 0 0 Plug.

L COMMENTS: File Specific Comments located to right of readings.

General Electric File Name:

NIA Refueling Outage - 11 R21 Oyster Creek Ultrasonic Thickness Measurement Date:

1011 !I2006 UT Procedure:

ER-AA-335-ocu Grid Procedure:

15328227-00)

Page 2 of 12 Data Sheet I

Examined by Lee Stone L-Level II Examined by NIA Level NIA Reviewed by: Kimberly Wert

,&V A 3

Level It fY Date 1011 8/2006 Date NIA Date 1 OM 812006

AmerGen 450 422 Bay 9 Area 20

Subject:

Drywell Corrosion I

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I Calculation Sheet

~

Appendix 7 System No.

Sheet No.

Calc. No.

Rev. No.

C-l301-187-E310-037 1

,187 A7-230f23 I

(Ref, Calc. SE-000243-002)

The minimum required thickness at this elevation is Tminsen 86 :=452 f

0 C

W 95- 'L m = -0.754 Location Curve Fit Projected to Plant End Of Life 650 650(

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I "Pper lower a

550 I

measured Tminsen g,j 0

Therefore the regression model shows that even at the lower 95% confidence band this location will not corrode to below Drywell Vessel Minimum required thickness by the plant end of life.

No Pits have been identified for this location

Ultrasonic Thickness Measurement Data Sheet I

I COMMENTS:

Forty nine (49) readings were taken using the 8"x 8" template to determine the average reading.

A 100% scan within the 8"x 8" area to determine the minimum and the maximum thickness.

A scan of the uppermost 1" of horizonal weld was performed, the minimum reading on the weld was 0.700" the maximum reading on the weld was 0.893". Unable to obtain readings on the lower part of weld due to rough and non-parallel surfaces.

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• w.uA.L L is 1 0 - 2 7 - 0 6 1012612008 Reviewed by: L e e Stone L ---

Level II Date

Ultrasonic Thickness Measurement 71' 6" Weld Scan Forty nine (49) readings were taken using the 8% 8" template to determine the average reading.

A 100% scan within the 8"x 8" area to determine the minimum and the maximum thickness.

A scan of the uppermost 1" of horizonal weld was performed, the minimum reading on the weld was 0.717" the maximum reading on the weld was 0.91 1". Unable to obtain readings on the lower part of weld due to rough and non-parallel surfaces.

spection area centered 4" left of vertical seam weld between plate 71-2 and plate 71-3, looking outward. Reference rawing 2E-187-29-001 RO.

?4M -&fd L gi /@-J7-006 Reviewed by: Lee Stone Level II Date 10/26/2006

AmerGen C

a l

c u

l a

t i

o n

S h

e g

t Appendix 4 Bay 15 Area 23

Subject:

Drywell Corrosion For the overall mean Calc. No.

Rev. No.

System No.

Sheet No.

C-l301-187-E310-037 1

1 87 A4-270f 32 Upperf := Thick predictf...

I 2

ipar predictf-n i c k qctuatmem)

S U m I

I lowerf := Thick predictf...

(year predictf-actualmean)

Total meatlS-2.Standard error. 1 +-

I

+

i (d+ 1)

S U m I

I General area Tmin for this elevation in the Drywell Tminsen 51 :=541 (Ref. Calc. SE-000243-002) f m = -0.777 min (Trnin-gen 51) - 30 I

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pr&ict*yea' predict.Fw p r e d i c t ~ D a t ~ ~ W prdia*2m.8 2.029.10 3 I.985.10 3

23' 6" Weld Scan Forty nine (49) readings were taken using the 8 x 8" template to determine the average reading.

100% scan of the weld and 100% scan within the 8"x 8" area to determine the minimum and the maximum thickness.

Minimum reading on weld was 0.689", Maximum reading on weld was 0.918".

nspection area centered 55" left of vertical seam weld between plate 23-1 9 and plate 23-20, looking outward. Reference drawing 2E-187-29-001 RO.

Level II Date 1 O/23/2006

% M W / Lfl / b - Z G U b Reviewed by: Lee Stone

Ultrasonic Thickness Measurement I

n I

I1 Damping:

WA Reject:

NIA 23,' 6" Weld Scan Fitter:

NIA I

Av$.

I 0.795 M d B 6 0 0 0 0 I

A B

C D

E F

G Min. c 1.141" 1 0 0 0 0 0 0 0 2

0 0 0 0 0 0 0 I

1 3 0 0 0 0 0 0 0 rn Max. 1.186" Forty nine (49) readings were taken using the 8% 8" template to determine the average reading.

100% scan of the weld and 100% scan within the 8"x 8" area to determine the minimum and the maximum thickness.

Minimum reading on weld was 0.865", Maximum reading on weld was 1.029" I

pection area centered 15" left of vertical seam weld between plate 23-1 8 and plate 23-1 9, looking outward. Reference

%R&$ic.L L 9 io-ZS-Ob awing 2E-187-29-001 RO.

I Level II Date 10/24/2006 Reviewed by: Lee Stone