ML072770559

Oyster Creek September 2007 Evidentiary Hearing - Applicant Exhibit 17, Gpu Calculation No. C-1302-187-5320-024, Rev. 0 (24 Calc.), O.C. Drywell Exterior UT Evaluation in the Sand Bed

ML072770559
Person / Time
Site:	Oyster Creek
Issue date:	01/12/1993
From:	Yekta M GPU Nuclear Corp
To:	NRC/SECY
SECY RAS
References
50-219-LR, AmerGen-Applicant-17, RAS 14224 C-1302-187-5320-024, Rev 00
Download: ML072770559 (54)

Text

-D 5 14-ý APPLICANT'S EXH. 17

- =Nuclear PRORlLRM STATE~MENT:

The purpose of this calculation is to evaluate the UT thickness measurements taken in the sandbed region during the 14R outage in support of O.C drywell corrosion mitigation project. These measurements were taken from the outside of the shell. Access to the sandbed region was achieved by cutting ten holes completely through the shield wall from the torus room.

2.0

SUMMARY

OF RESULTS:

This calculation demonstrates that the UT thickness measurements for all bays meet the minimum uniform and local required -hicknesses.

The evaluation was performed by evaluating the UT measurements for each bay and dispositioning them relative to the uniform thickness of 0.736 inch used in GE structural analysis reports. Additional acceptance criteria was developed to address measurements below 0.736 inch. The results are summarized in Table 1.

UT measurements for bays 3, 5, 7, 9, and 19 were all above the 0.736 inches and therefore acceptable.

UT measurements for bays 11, 15, and 17 were all above 0.736 inches except for one measurement for each bay. After further evaluation of these three measurements including an examination of adjacent areas, it was determined that they were acceptable as shown on Table 1.

UT measurements for bays 1 and 13 were evaluated using detailed criteria described in this calculation and the results are summarized in Table 1 below:

U.S. NUCLEAR REGULATORY COMMISSION DOCKETED Inthe MateWof ha&EP4 WVERa( 20-> UP.

USNRC DocketNo5Q-O'29-EI '1Ewtib~it No. _____

October 1, 2007 (10:45am) OFFERED b~cnL-_____

OFFICE OF SECRETARY NR St-,if RULEMAKINGS AND ADJUDICATIONS STAFF Acton Taken: (DITTED -RJECTED WITHDRAWN Re"oe/C[ e&Aiv\

OCLRD0020687 Ieni P tali! = S E C y- 0 as-

[ Muclear Calculation Sheet 2.0 SUMM4ARY OF RESULTS ( Continued ):

Summary of UT Evaluations Table (1) jDY/LIT UT e:( )...

.Wf": .urmct Nlqm~e .&

.~..:.j..M n Dc/Vh'sUey' "1'(Epuaion):j.

1::,cat.an .*.. :":. :*.i:*..

.........  :.-:.7..:~ .*.. 3Y... ::.#* i(!)*(2 Yifi: *i~::::'. :~I>:.::i:*i:*::ii!.i:Ž:!li'~

Bay 11/ Loc. 1

• 0.705" 0.246" 0.200" 0.751' Acceptable Bay 15/ Loc. 9 0,722" 0.337" 0.200" .Acceptabl Bay 17/ Loc 9 0.720" 0.351" 0.200" 0,871" Acceptable Bay 1/ Loc, I R720" 0.228" 0.200" 0.738 Acceptable Bay 1/ Loc. 2 0.716" 0.143" 0.200" 0.659" Acceptable Bay 1/ Loc. 3 0.705" 0347" 0.200" 0.852" Acceptable Bay 1/ Loc. 5 0.710" 0313" 0.200" 0.823" Acceptable Bay 1/ Loe. 7 0.700, 0.266" 0.210" 0.766" Acceptable Bay 1/ Loc. 11 0.714" 0.212" 0.200" 0.726" Acceptable Bay 1/ Loc. 12 0.724" 0.301" 0.200" 0.825" Acceptable Bay 1/ Lor. 21 0.726" 0.211" 0.200" O.737" Acceptable Bay 13/ Loc. 1 0.672" 0.351" 0.200" 0.823' Acceptable Bay 13/ Loc. 2 0.729" 0.360" 0.200" 0.882" Acceptable Bay 13/ Loe. S 0.718" 0-217" 0.200" 0.735" Acceptable Bay 13/ Loc. 6 0.655" 0.301" 0.200" 0.756" Acceptable Bay 13/ Loc. 7 0.618" 0.25T" 0.200" 0.675' Acceptable Bay 13/ Loc. 8 0.718" 0.278" 0.200" 0.796" Acceptable Bay 13/ Loc. 10 0.728" 0.211" 0.200" 0.739" Acceptable Bay 13/ Loc. 11 0.685" 0.256" 0.200" 0.741" Acceptable Bay 13/ to. 15 0.693" 0.273" 0.200' 0.756" Acceptable 0CLR00020688

ECONuclear Calculation Sheet Subject Caic No. Rev. No. Sheet No.

O.C DrvwelIl EXt. Ut- Evaluatio i Sandbed C32-87-5320-024 I 0 3 Of Originator Dat¢ R -viewed by Date MARK YEKTA 01/12/93 S. C. Tummineili 04/I 3,0

REFERENCES:

3.1 Drywell sandbed region pictures (see Appendix C ).

3.2 An ASME Section VIII Evaluation of the Oyster Creek Drywell for Without Sand Case Performed by GE - Part 1 Stress Analysis, Revision 0 dated February, 1991 Report 9-3.

3.3 An ASME Section VIII Evaluation of the Oyster Creek Drywell for Without Sand Case Performed by GE - Part 2 Stability Analysis, Revision 2 dated November, 1992 Report 9-4.

3.4 ASME Section III Subsection NE Class MC Components 1989.

3.5 GE letter report " Sandbed Local Thinning and Raising the Fixity Height Analysis ( Line Items 1 and 2 In Contract PC-0391407 )" dated December 11, 1992.

3.6 GPUN Memo 5320-93-020 From K. Whitmore to J. C. Flynn "Inspection of Drywell Sand Bed Region and Access Hole",

Dated January 28, 1993.

4.0 ASSUMPTIONS AND BASIC DATA:

4.1 Raw UT measurements are summarized for each bay in the body of calculation.

4.2 Observations of the outside surface of the drywell shell indicate a rough surface with varying peaks and valleys.

In order to characterize an average roughness representing the depth difference of peaks and valleys, two impressions were made at the two lowest UT measurements for bay 13 using Epoxy putty Appendix A presents the calculation of the depth of surface roughness using the drywell shell impressions taken in the roughest bay. Two locations in bay 13 were selected since it is the roughest bay. Approximately 40 locations within the two impressions were measured for depth and the average plus one standard deviation was calculated. A value of 0.200 inch was used in this calculation as a conservative depth of uniform dimples for the entire outside surface of the drywell in the sandbed region .

OCLR00020689

= Nuclear Calculation Sheet Subject Cale No No. Sheet No.

O.C Drvwell Ext. Ut Evaluation tn Sandbed Q-1302-17-520-024 0 42-Originator Dale Reviewed by Date MARK YEKTA 01/12/93 S. C. Tumminelli

5.0 CALCULATION

ACCEPTANCE CRITERIA - GENERAL WALL:

The acceptance criteria used to evaluate the measured drywell thickness is based upon GE reports 9-3 and 9-4 (Ref. 3.2 &

3.3) as well as other GE studies (Ref. 3.5) plus visual observations of the drywell surface ( Ref. 3.6 and Appendix C

). The GE reports used an assumed uniform thickness of 0.736 inches in the sandbed area. This area is defined to be from the bottom to top of the sandbed, i.e., El. 8'-11i" to El.

12'-3" and extending circumferentially one full bay.

Therefore, if all the UT measurements for thickness in one bay are greater than 0.736 inches the bay is evaluated to be acceptable. In bays where measurements are below 0.736 inches, more detailed evaluation is performed.

This detailed evaluation is based, in part, on visual observations of the shell surface plus a knowledge of the inspection process. The first part of this evaluation is to arrive at a meaningful value for shell thickness for use in the structural assessment. This meaningful value is referred to as the thickness for evaluation. It is computed by accounting for the depth of the spot where the thickness measurement is taken considering the roughness of the shell surface. The surface of the shell has been characterized as being "dimpled" as in the surface of a golf ball where the dimples are about one half inch in diameter ( Appendix C )'.

Also, the surface contains some depressions 12 to 18 inches in diameter not closer than 12 inches apart, edge to edge (Ref.

3.6). Appendix A presents the calculation of the depth of surface roughness using the drywell shell impressions taken in the roughest bay. Two locations in bay 13 were selected since it is the roughest bay. Approximately 40 locations within the two impressions were measured for depth and the average plus one standard deviation was calculated to be at 0.186 inches.

A value of 0.200 inch was used in this calculation as a conservative depth of uniform dimples for the entire outside surface of the drywell in the sandbed region OCLR00020690

[ 2JNuciear Calculation Sheet

5.0 CALCULATION

ACCEPTANCE CRTTERIA - GENERAL WALL: (Continued)

The inspection focused on the thinnest portion of the drywell, even if it was very local, i.e., the inspection did not attempt to define a shell thickness suitable for structural evaluation. Observations indicate that some inspected spots are very deep. They are much deeper than the normal dimples found, and very local, not more than 1 to 2 inches in diameter. (Typically these observations were made after the spot was surface prepped for UT measurement. This results in a wide dinple to accommodate the meter and slightly deeper than originally found by 0.030 to 0.100 inches). The depth of these areas was measured and averaged with respect to the top of local areas as shown in Appendix A. These depths are referred to herein as the AVG micrometer measurements. The thickness for evaluation is then computed from the above information as:

T (evaluation) UT (measurement) + AVG (micrometer)

- 0.200 inches where:

T (evaluation) thickness for evaluation UT (measurement) thickness measurement at the area (location)

AVG (micrometer) average depth of the area relative to its immediate surroundings 0.200 inch a conservative value of depth of.typical dimple on the shell surface.

After this calculation, if the thickness for analysis is greater than 0.736 inches; the area is evaluated to be acceptable.

0CLR00020691

[ Nuclear Calculation Sheet Subject Calc No. Rev. No. Sheet No.

O.C Drvwell Ext. Ut Evaluation in Sandbed C-1302-187---5320-024 0 6 Originator Date Reviewed by Date MARK YEKICA 01/12/93 S. C Turnminelli 0

5.0 CALCULATION

ACCEPTANCE CRITERIA - LOCAL WALL:

If the thickness for evaluation is less than 0.736 inches, then the use of specific GE studies is employed (Ref. 3.5).

These studies contain analyses of the drywell using the pie slice finite element model, reducing the thickness by 0.200 inches in an area 12 x 12 inches in the sandbed region, tapering to original thickness over an additional 12 inches, located to result in the largest reduction possible. This location is selected at the point of maximum deflection of the eigenvector shape associated with the lowest buckling load.

The theoretical buckling load was reduced by 9.5%from 6.41 to 5.56. Also, the surrounding areas of thickness greater than 0.736 inches is also used to adjust the actual buckling values appropriately. Details are provided in the body of the calculation.

ACCEPTANCE CRITERIA - VERY LOCAL WALL (2-2 Inches In DIAMETER):

All UT measurements below 0.736 inches have been determined to be in isolated locations less than 2k inches in diameter.

The acceptance criteria for these measurements confined to an area less than 21/2 inches in diameter is based on the ASME Section III Subsection NE Class MC Components paragraph NE 3332.1 and NE 3335.1 titled "OPENING NOT REQUIRING REINFORCEMENT AND REINFORCEMENT OF MULTIPLE OPENINGS".

These Code provisions allow holes up to 21/2 inches in diameter in Class MC vessels without requiring reinforcement.

Therefore, thinned areas less than 21/2 inches in diameter need not be provided with reinforcement and are considered local.

Per NE 3213.10 the stresses in these regions are classified as local primary membrane stresses which are limited to an allowable value of 1.5 Sm. Local areas not exceeding 21/2 inches in diameter have no impact on the buckling margins.

Using the 1.5 Sm criteria given above, the required minimum thickness in these areas is:

T ( required ) ( 2/3 ) * ( 0.736 ) = 0.490 inches Where 2/3 is Sm/l.5Sm and is the ratio of the allowable stresses.

UT thickness measurements for all ten bays are above 0.490 inches.

OCLROO020692

BO uclear Calculation Sheet Subject Calc No. Rev. No. Sheet No.

0. Q Drywgll xt . U~t Evaluation in Sandbed C-1302-187-5320-024] 0 7 Originator Date Reviewed by Date MARK YEKTA 01/12/93 S. C Turnminelli

5.0 CALCULATION

UT EVALUATION:

BAY.# 1:

The outside surface of this bay is rough and full of dimples similar to the outside surface of golf ball.

This observation is made by the inspector who located the thinnest areas for the UT examination. This inspection focused on the thinnest areas of the drywell, even if it was very local, i.e., the inspection did not attempt to define a shell thickness suitable for structural evaluation. The shell appears to be reLatively uniform in thickness except for a band of corrosion which looks like a "bathtub" ring, located 15 to 20 inches below the vent pipe reinforcement plate, i.e, weld line as shown in Figure 1. ( Figure 1 and others like figures presented in this calculation are NOT TO SCALE). The bathtub ring is 12 to 18 inches wide and about 30 inches long located in the center of the bay. Beyond the bathtub ring on both sides, the shell appears to be uniform in thickness at a conservative value of 0.800 inches. Above the bathtub ring the shell exhibits no corrosion since the original lead primer on the vent pipe/reinforcement plate is intact. Measurements 14 and 15 confirm that the thickness above the bathtub ring is at 1.154 inches starting at elevation 11'-00". Below the bathtub ring the shell is uniform in thickness where no abrupt changes in thicknesses are present. Thickness measurements below the bathtub ring are all above 0.800 inches except location 7 which is very local area.

Therefore, a conservative mean thickness of 0.800 inches is estimated to represent the evaluation thickness for this bay. Given a uniform thickness of 0.800 inches, the buckling margin for the refueling load condition can be recalculated based on the GE report 9-4 (Ref. 3.3). The theoretical buckling strength from report 9-4 (ANSYS Load Factor) is a square function of plate thicknesses.

Therefore, a new buckling capacity for the controlling refueling load combination is calculated to be at 13%

above the ASME factor of safety of 2 as shown in Appendix B.

0CLR00020693

SHuclear Calculation Sheet Subject Calc No. IRev. No. Sheet No.

o.C Qrvkwe11EXt, Ut E va~uato in anabeg -Q41-ot-Dz

-uz u V U Da Originator Date Reviewed by Date MARK YEK.TA 01/12/93 S. C. Tumminelli 04/16/93

5.0 CALCULATION

UT EVALUATION:

BAY # 1 ( Continued):

Locations 1, 2, 3, 4, 5, 10, 11, 12, 13, 20, and 21 are confined to the bathtub ring as shown in Figure 1. An average value of these measurements is an evaluation thickness for this band as follows; Location Evaluation Thickness 1 0.738" 2 0.659" 3 0.852" 4 0.760" 5 0. 823" 10 0.839" 11 0.726" 12 0.825" 13 0.79211 20 0.965" 21 0.737" Average = 0.792" An average evaluation thickness of 0.792 inches for the bathtub ring may raise concern given that the bathtub ring is noticeable and that the difference between its average evaluation thickness (0.792 inches) and the average thickness taken for the entire region (0.800 inches) is only 0.008 inches. This results from the fact that average micrometer readings were generally not taken for the remainder of the shell since each reading was greater than 0.736 inches. In reality, the remainder of the shell is much thicker than 0.800 inches. The appropriate evaluation thickness can not be quantified since no micrometer readings were taken.

The individual measured thicknesses must also be evaluated for structural compliance. Table l-a identifies 23 locations of UT measurements that were selected to represent the thinnest areas, except locations 14 and 15, based on visual examination. These locations are a deliberate attempt to produce a minimum measurement. Locations 14 and 15 were selected to confirm that no corrosion had taken place in the area above the bathtub ring.

0CLR00020694

= Nuclear Calculation.Sheet Subject Caic No. Re. No, Sheet No.

.C TDr'vtwell RXt U~t Evaluation in Sandbed C-1302-187-5520-024 0 9 Origi;iator Date Revimc d by Date MARK YEKrA 01/12/93 S. C. Tumminelli 0

5.0 CALCULATION

UT EVALUATION:

BAY # 1 ( Continued):

Eight locations shown in Table 1-a (1, 2, 3, 5, 7, 11, 12, and 21) have measurements below 0.736 inches.

Observations indicate that these locations were very deep and not more than 1 to 2 inches in diameter. The depth of each of these areas relative to its immediate surroundings was measured at 8 locations around the spot and the average is shown in Table 1-a. Using the general wall thickness acceptance criteria described earlier, the evaluation thickness for all measurements below 0.736 inches were found to be above 0.736 inches except for two locations, 2 and 11, as shown in Table 1-b. Locations 2 and 11 are in the bathtub ring and are about 4 inches apart. This area is characterized as a local area 4 x 4 inches located at about 15 to 20 inches below the vent pipe reinforcement plate with an average thickness of 0.692 inches. This thickness of 0.692 inches is 0.108 inches reduction from the conservative estimate of 0.800 inches evaluation thickness for the entire bay. In order to quantify the effect of this local region and to address structural compliance, the GE study on local effects is used (Ref. 3.5).

This study contains an analysis of the drywell shell using the pie slice finite element model, reducing the thickness by 0.200 inches (from 0.736 to 0.536 inches) in an. area 12 x 12 inches in the sandbed region located to result in the largest reduction possible. This location is selected at the point of maximum deflection of the eigenvector shape associated with the lowest buckling load. The theoretical buckling load was reduced by 9.5%.

The 4 x 4 inches local region is not at the point of maximum deflection. The area of 4 x 4 inches is only 11%

of the 12 x 12 inches area used in, the analysis.

Therefore, this small 4 x 4 inches area has a negligible effect on the buckling capacity of the structure.

In summary, using a conservative estimate of 0.800 inches for evaluation thickness for the entire bay and the presence of a bathtub ring with an evaluation thickness of 0.792 inches plus the acceptance of a local area of 4 x 4 inches based on the GE study, it is concluded that the bay is acceptable.

OCLROO020695

Nuclear Calculation Sheet

5.0 CALCULATION

UT EVALUATION:

DAY # 1 (Continued):

Bay # 1 UT Data Table 1-a Lo~ton UT M-a~ureirontj Average.

S.....*(incheq),

1 0.720 0.218 2 0.716 0.143 3 0.705 0.347 4 0.760 ---

5 0.710 0.313 6 0.760___

7 0.700 0.266 8 0.805 ---

9 0.805 10 0.839 ---

11 0.714 0.212 12 0.724 0.301 13 0.792 ---

14 1.147 15 1.156 16 0.796 ---

17 0.860 18 0.917 19 0.890 20 0.965 ---

21 0.726 0.211 22 0.852 23 0.850 OCLROO020696

EOHuclear Calculation Sheet

5.0 CALCULATION

UT EVALUATION:

BAY # 1:(Continued)

SUMMARY

OF Measurements BELOW 0.7 Table 1-b

____(3)___(41) 1 0.720" 0.218" 0.200" 0.738" Acceptable 2 0.716" 0.143" 0.200" 0.659" Acceptable 3 0.705" 0.347" 0.200" 0.852" Acceptable 5 _ 0.710" 0.313" 0.200" 0.823" Acceptable 7 0.700" 0.266" 0.200" 0.766" Acceptable 11 0,714' 0.212" 0.200" 0.726" Acceptable 32 0.724" 0301" 0.200" 0.825" Acceptable 21 0.726" 0.211" 0.200" 0.737"_ Acceptable 0CLR00020697

uclear Calculation Sheet BAY #1 DATA NOTES:

1. All 'Location" measurements from intersection of the DW shell and vent collar fillet welds.

2. Pit depts are average of four readings taken at 0/450190'0i350 within 1"band surrounding ground spots. Only measured where remaining wall thk.

was below 0.736".

14 9

15 0

MM U

S11'ELL 9

V .19 7 "I 66 23,.4,& 17 ,

FIGURE. (1) 0CLR00020698

=Nuclear Calculation Sheet Subject CaIc No. Rev. No. Sheet No.

O.C Drywell Ext. Ut Evaluation in Sandbed C-1302-187-5320-024 ] 0- 13 of 54 Originator Date Revicwed by Date MARK YEKTA 01/12/93 S. C Tumminelli 04/16/93

5.0 CALCULATION

UT EVALUATION:

BAY # 3:

The outside surface of this bay is rough, similar to bay one, full of dimples comparable to the outside surface of golf ball. This observation is made by the inspector who located the thinnest areas for the UT examination. The shell appears to be relatively uniform in thickness except for a bathtub ring 8 to 10 inches wide approximately 6 inches below the vert header reinforcement plate. The upper portion of the shell beyond the band exhibits no corrosion where the original red lead primer is still intact. Eight locations were selected to represent the thinnest areas based on the visual observations of the shell surface (Fig. 3). These locations are a deliberate attempt to produce a minimum measurement. Table 3.shows measurements taken to measure the thicknesses of the drywell shell using a D-meter.

The results indicate that all of the areas have thickness greater than the 0.736 inches.

Given the UT measurements, a conservative mean evaluation thickness of 0.850. inches is estimated for this bay and therefore, it is concluded that the bay is acceptable.

Bay.# 3 UT Data Table 3 IiLocation Tvezag

...

..Measurement: .. MicrObreter 1 0.795 ---

2 1.000 3 0.857 ---

4 0.898 ---

5 0.823 ---

6 0.968 7 0.826 8 0.780 OCLROO020699

Nuclear Calculation Sheet BAY #3-D"I ATA NOTES:

1. All "Location" measurements from Intersection of the DW shell and vent collar fillet welds.

I 6 5 3S S S4

.7 SHEW SHELL FIGURE (3)

OCLROOD20700

Nuclear Calculation Sheet

5.0 CALCULATION

UT EVALUATION:

BAY # 5:

The outside surface of this bay is rough and very similar to bay 3 except that the local areas are clustered at the junction of bays 3 and 5, at about 30 inches above the floor. The shell surface is full of dimples comparable to the outside surface of golf ball. This observation is made by the inspector who located the thinnest areas for the UT examination. The shell appears to be relatively uniform in thickness. Eight locations were selected to represent the thinnest arpas based on the visual observations of the shell surface 'see Fig. 5). These locations are a deliberate attempt to produce a minimum measurement. Table 5 shows readings taken to measure the thicknesses of the drywell shell using a D-meter. The results indicate that all of the areas have thickness greater than the 0.736 inches.

Given the UT measurements, a conservative mean evaluation thickness of 0.950 inches is estimated for this bay and therefore, it is concluded that the bay is acceptable.

Bay # 5 UT Data Table 5

'Localtionr  :,JAveragg,

'~asti ement, -- micrometer 1 0.970 2 1.040 ---

3 1.020 ---

4 0 . 910 ---

5 0.890 ---

6 1.060 7 0.990 8 I .010--

OCLROO0207O1

EMMmuclear BAY #5 DATA NOTES:

1. Inthis bay DW shell (butt) weld is about 8"to the right of CIL of vent tube. Therefore - all measurements were taken from a linedrawn on shell which approx.

coincide with vent tube CIL DW SHELL 6 4 2 1 9

42 !3 FIGURE (5)

OCLRO0020702

EONuclear Calculation Sheet

5.0 CALCULATION

UT EVALUATION:

The observation of the drywell surface for this bay showed uniform dimples in the corroded area, but they are shallow compared to those in bay 1. The bathtub ring seen in the other bays, was not very prominent in this bay. This observation is made by the inspector who located the thinnest areas for the UT examination. The shell appears to be relatively uniform in thickness.

Seven locations were selected to represent the thinnest areas based on the visual observations of the shell surface (Fig. 7). These locations are a deliberate attempt to produce a minimum measurement. Table 7 shows readings taken to measure the thicknesses of the drywell shell using a D-meter. The results indicate that all of the areas have thickness greater than the 0.736 inches.

Given the UT measurements, a conservative mean evaluation thickness of 1.00 inches is estimated for this bay and therefore, it is concluded that the bay is acceptable.

Table 7 Location" V :TAv~erage

....... eri -IMicrom~ter 1 0.920 ---

2 1.016 ---

3 0.954 ---

4 1.040 ---

5 1.030 ---

6 1.045 ---

7 1.000 ---

OCLRO0020703

=Nuclear Calculation Sheet Subject Calc No. Rev. No. Sheet No.

OC Drvwell Ext. Ut Evaluation in Sandbe C-130- 7-5320-024 0 18o-4 Originator Date Reviewed by Date MARK YEKTA 01/12/93 S. C. Tumminelli 04/16/93 E34AY #7 DATA NOTES:.

1. All measurements from the Intersection of DW shell (butt) and vent collar (fillet) welds.

6 4 DW 7

0 5 2.1 SHELL FIGURE (7)

OCLR00020704

= Nuclear Calculation Sheet

5.0 CALCULATION

UT EVALUATION:

BAY # 9:

The observation of the drywell shell for this bay was very similar to bay 7 except that the bathtub ring was more evident in this bay. The shell appears to be relatively uniform in thickness except for a bathtub ring 6 to 9 inches wide approximately 6 to 8 inches below the vent header reinforcement plate. The upper po*rtion of the shell beyond the band exhibits no corrosioon where the original red Lead primer is still intact. Eight locations were selected to represent the thinnest areas based on the visual observations or the shell surface (Fig. 9). These locations are a deliberate attempt to produce a minimum measurement. Table 9 shows readings taken to measure the thicknesses of the drywell shell using a D-meter. The results indicate that all of the areas have thickness greater than the 0.736 inches.

Given the UT measurements, a conservative mean evaluation thickness of 0.900 inches is estimated for this bay and therefore, it is concluded that the bay is acceptable.

Bay # 9 UT Data Table 9 ILocat~on UT)veraqe Measurement Microm~eter

(,ixiehes) (inches) 1 0.960 ---

2 0.940 3 0.994 4 1.020 5 0.985 ---

6 0.820 7 0.825 8 0.791 ___

9 0.832 ---

10 0.980 OCLR00020705

[7ri a] imuclear six Calculation Sheet BAY #9 DATA NOTES:

1. Al muurements from Interasetlon of the OW Mhell (butt) and vent collar (fillet) welds.

3 .

8 7

• SMELL 10 0

FIGURE (9)

OCLROD020706

[M Nuclear Calculation Sheet Subject Ca*cNo. Rev. No. Sheet No.

O.C Dr~vwQll Ext. Ut Evaluatio i Sandbed C-1302-187-5320-024 [ 21 Orginator Date Reviewed by Date MARK YEKTA 01/12/93 S. C Tumminelfi 0

5.0 CALCULATION

UT EVALUATION:

BAY # 11:

The outside surface of this bay is rough, similar to bay 1, full of uniform dimples comparable to the outside surface of a golf ball. The shell appears to be relatively uniform in thickness except for local areas at the upper right corner of Figure 11, located it -.bout 10 to 12 inches below the vent pipe reinforcement plate.

Eight locations were selected to represent tae thinnest areas based on the visual observations of the shell surface (Fig. 11). These locations are a deliberate attempt to produce a minimum measurement. Table 11-a shows readings taken to measure the thicknesses of the drywell shell using a D-meter. The results indicate that all of the areas have thickness greater than the 0.736 inches, except one location. Location 1 as shown in Table 11-a, has a reading below 0.736 inches.

Observations indicate that this location was very deep and not more than 1 to 2 inches in diameter. The depth of area relative to its immediate surroundings was measured at 8 locations around the spot and the average is shown in Table 11-a. Using the general wall thickness acceptance criteria described earlier, the evaluation thickness for location. 1 was found to be above 0.736 inches as shown in Table 11-b.

Given the UT measurements, a conservative mean evaluation thickness of 0.790 inches is estimated for this bay and therefore, it is concluded that the bay is acceptable.

0CLR000207077

Nuclear Calculation Sheet

5.0 CALCULATION

UT EVALUATION:

BAY # 11 (Continued):

Bay # 11 UT Data Table 11-a

• Locat~ion - T Aveirage

'Z~eu~rfleit Micromef-er

______ .(.inches) (inches) 1 0.705 0.246 2 0.770 ---

3 0.832 ---

4 0.755 5 0.831 ---

6 0.800 ---

7 0.831 8 0.815 Summary of Measurements Below 0.736 Inches Table 11-b 0CLR00020708

EONuclear Calculation Sheet BAY #11 DATA NOTES:

1. All measurements from Interw4,tion of the DW sh"ll (butt) and vent collar (illlet) welds.

2. Pit depths are average of four readings taken at 4,45"/901 35" within V band surrounding the ground spots. Thl measurment wet only taken when wall thickness wC- below 0.736'.

SEW 3

6 "4

16 SHkzELL 6 92 "5 .7 FIGURE ( 11 )

OCLRkOO020709

Tl uclear Calculation Sheet Subject CaIc No. Rev. No. Sheet No.

O.C Drvwell Ext. Ut Evaluation in Sandb*d C-1302-187-5320-024 Q 24 Originator Date Reviewed by Date MARK YEkTA 01/12/93 S. C Tumminelli 04

5.0 CALCULATION

UT EVALUATION:

BAY # 13:

The outside surface of this bay is rough and full of dimples similar to bay 1 as shown in Appendix C. This observation is made by the inspector who located the thinnest areas in deep valleys thereby biasing the remaining wall measurements to the conservative side.

This inspection focused on the thinnest areas, even if very local, i.e., the inspection did not attermot to define a shell thickness suitable for structural evaluation. The variation in shell thickness is greater in this bay than in the other bays. The bathtub ring below the Vent pipe reinforcement plate was less prominent than was seen in other bays. The corroded areas are about 12 to 18 inches in diameter and are at 12 inches apart, located .- the middle of the sandbed.

Beyond the corroded areas on both sides, the shell appears to be uniform in thickness at a conservative value of 0.800 inches. Near the vent pipe and reinforcement plate the shell exhibits no corrosion since the original lead primer on the vent pipe/reinforcement plate is intact. Measurement 20 confirms that the thickness above the bathtub ring is at 1.154 inches.

Below the bathtub ring the shell appears to be fairly uniform in thickness where no abrupt changes in thickness are present. Thickness measurements below the bathtub ring are all 0.800 inches or better.

Therefore, a conservative mean thickness of 0.800 inches is estimated to represent the evaluation thickness for this bay. Given a uniform thickness of 0.800 inches, the buckling margin for the refueling load condition is recalculated based on the GE report 9-4 (Ref. 3.3). The theoretical buckling strength from report 9-4 (ANSYS Load Factor) is a square function of plate thicknesses.

Therefore, a new buckling capacity for the controlling refueling load combination is calculated to be at 13%

above the ASME factor of safety of 2 as shown in Appendix B.

OCLROO02071 0

shn EMINuclear Calculation Sheet

5.0 CALCULATION

UT EVALUATION:

BAY # 13 ( Continued ):

Locations 5, 6, 7, 8, 10, 11, 14, and 15 are confined to the bathtub ring as shown in Figure 13. An average value of these measurements is an evaluation thickness for this band as follows; Location Evaluation Thickness 5 0.735" 6 0.75615 7 0.675" 8 0.796" 10 0.739"1 11 0.741" 12 0.885" 14 0.868" 15 0.756" 16 0.829" Average = 0.778" The inspector suspected that some of the above locations in the bathtub ring were over ground. Subsequent locations with suffix A, e.g. 5A, 6A, were located close to the spots in question and were ground carefully to remove the minimum amount of metal but adequate enough for UT examination as shown in Table 13-a. The results indicate that all subsequent measurements were above 0.736 inches. The average micrometer measurements taken for these locations confirm the depth measurements at these locations. In spite of the fact that the original measurements were taken at heavily ground locations they are the ones used in the evaluation.

The individual measurements must also be evaluated for structural compliance. Table 13-a identifies 20 locations of UT measurements that were selected to represent the thinnest areas, except location 20, based on visual examination. These locations are a deliberate attempt to produce a minimum measurement. Location 20 was selected to confirm that no corrosion had taken place in the area above the bathtub ring.

OCLR00020711

ý Huclear Calculation Sheet Subject CaIc No. Rev. No. Sheet No.

O.C Drvwell Ext. Ut Evaluation in Sandbed C-1302-187-5320-024'1 0 _2rI Originator Date Reviewed by Date MARK YEKTA 01/12/93 S. C. Tumminelli 0

5.0 CALCULATION

UT EVALUATION:

BAY # 13 ( Continued ):

Nine locations-shown in Table 13-a (1, 2, 5, 6, 7, 8, 10, 11, and 15) have measurements below 0.736 inches.

Observations indicate that these locations were very deep, overly ground, and not more than 1 to 2 inches in diameter. The depth of each of these areas relative to its immediate surroundings was measured at 8 locations around the spot and the average is shown in Table 13-a.

Using the general wall thickness acceptance criteria described earlier, the evaluation thickness for all measurements below 0.736 inches were found to be above 0.736 inches except for two locations, 5 and 7, as shown in Table 13-b. In addition, subsequent measurements close to the locations identified above, were taken and they were all above 0.736 inches. Locations 5 and 7 are in the bathtub ring and are about 30 inches apart. These locations are characterized as local areas located at about 15 to 20 inches below the vent pipe reinforcement plate with an evaluation thicknesses of 0.735 inches and 0.677 inches. The location 5 is near to location 14 for an average value of 0.801 inches and therefore acceptable. Location 7 could conservatively exist over an area of 6 x 6 inches for a thickness of 0.677 inches.

This thickness of 0.677 inches is a full 0.123 inches reduction from the conservative estimate of 0.800 inches evaluation thickness for the entire bay. In order to quantify the effect of this local region and to address structural compliance, the GE study on local effects is used (Ref. 3.5).

This study contains an analysis of the drywell shell using the pie slice finite element model, reducing the thickness by 0.200 inches (from 0.736 to 0.536 inches) in an area 12 x 12 inches in the sandbed region located to result in the largest reduction possible. This location is selected at the point of maximum deflection of the eigenvector shape associated with the lowest buckling load. The theoretical buckling load was reduced by 9.5%.

The 6 x 6 inch local region is not at the point of maximum deflection. The area of 6 x 6 inches is only 25%

of the 12 x 12 inches area used in the analysis.

Therefore, this small 6 x 6 inch area has a negligible effect on the buckling capacity of the structure.

OCLR00020712

Iwo EMINsuclear Calculation Sheet Subject Calc No. Rev. No. Sheet No.

O.C Drywell Ext. Ut Evaluiation in Sandbed C-1302.187-5320-024[ 0- 27 of S*

Originator Date Reviewcd by Date MARK YEKrA 01/12/93 S. C. Tumminelli 04/16/93

5.0 CALCULATION

UT EVALUATION:

DAY # 13 ( Continued ):

In summary, using a conservative estimate of 0.800 inches for evaluation thickness for the entire bay and the presence of a bathtub ring with a evaluation thickness of 0.778 inches plus the acceptance of a local area of 6 x 6 inches based on the GE study, it is concluded that the bay is acceptable.

Bay # 13 UT Data Table 13-a

-Locatioa UT' ZMeasiarenent Average 1/1A 0.672/0.890 0.351 2/2A 0.722/0.943 0.360 3 0.941 ----

4 0.915 ---

5/5A 0.718/0.851 0.217 6/6A 0.655/0.976 0.301 7/7A 0.618/0.752 0.257 8/8A 0.718/0.900 0.278 9 0.924 ---

10/10A 0.728/0.810 0.211 11/11A 0.685/0.854 0.256 12 0.885 ---

13 0.932 ---

14 0.868 ---

15/15A 0.683/0.859 0.273 16 0.829 ---

17 0.807 ---

18 0.825 ---

19 0.912 ---

.20 1-170 ---

OCLROO020713

Nuclear Calculation Sheet

5.0 CALCULATION

UT EVALUATION:

BAY # 13 ( Continued Summary of Measurements Below 0.736 Inches Table 13-b

• * *;*:*.:**............,*e*

'Locaion Ut.Mc.5iieiicn AVGv.Mifmntcr~% ýMea.Ii:Depthi/Vally, T<1(Evh Idion) Remarks~j 1 0.672" 0.351' 0.200' 0.823' Acceptable 2 0.722" 0.360' 0.200" 0882" Acceptable 5 0.718" 0.217" 0200" 0.735" Acceptable 6 0.655" 0.301" 0.200" 0.756" Acceptable 7 0.618" 0.257" 0.200" 0.675" Acceptable 8 0.718" 0.278" 0.200' 0.796" Acceptable 10 0.728" 0.211" 0.200" 0.739" Acceptable 11 0.685" 0.256" 0.200" 0.741" Acceptable 15 0.683' 0.273" 0.200" 0.756" Acceptable OCLRO0020714

Wo 023nuclear Calculation Sheet FIGURE ( 13 )

OCLROO020715

ý Huclear Calculation Sheet Subject Cale No. Rev. No. Sheet No.

O.C Drvwnell Ext. Ut Evatluation in Sandbed tC-1109-187-53-2-0-024 [ 0 30 Originator Date Reviewed by . Date MARK YEKTA 01/12/93 S. C.Tumminel

5.0 CALCULATION

UT EVALUATION:

BAY # 15:

The outside surface of this bay is rough, similar to bay 1, full of uniform dimples comparable to the outside surface of golf ball (Appendix C ). The bathtub ring seen in the other bays, was not very prominent in this bay. This observation is made by the in-pector who located the thinnest areas for the UT examination. The upper portion of the shell beyond the ring exhibits no corrosion where the original red lead primer is still intact. The shell *-ppears to be relatively uniform in thickness.

Eleven locations were selected to represent the thinnest areas based on the visual observations of the shell surface (Fig. 15). These locations are a deliberate attempt to produce a minimum measurement. Table 15-a shows readings taken to measure the thicknesses of the drywell shell using a D-meter. The results indicate that all of the areas have thickness greater than the 0.736 inches, except one location. Location 9 as shown in Table 15-a, has a reading below 0.736 inches.

Observations indicate that this location was very deep and not more than 1 to 2 inches in diameter. The depth of area relative to its immediate surrounding was measured at 8 locations around the spot and the average is shown in Table 15-a. Using the general wall thickness acceptance criteria described earlier, the evaluation thickness for location 9 was found to be above 0.736 inches as shown in Table 15-b.

Given the UT measurements, a conservative mean evaluation thickness of 0.800 inches is estimated for this bay and therefore, it is concluded that the bay is acceptable.

0CLR00020716

MMuclear Calculation Sheet

5.0 CALCULATION

UT EVALUATION:

BAY # 15:

Bay #15 UT Data Table 15-a Docat.ion'. U Average Mea snltenent mi~cromfetnrs

-(inches.) (nfeý)

1 0.786 ---

2 0.829 3 0.932 ---

4 0.795 5 0.850 ---

6 0.794 ---

7 0.808 ---

8 0.770 ---

9 0.722 0.337 10 0.860 ---

11 0.825 Summary of Measurements Below 0.736 Inches Table 15-b Ldac~to UT (Jmcasur~mcnt AV6,,Micitmeie~r MeaQ Dqi/ap e ý(Evaluafiu) n.tark 9 0.722" 0.337" Olm"O 0.959, Atceptable OCLROO020717

uclear

.BAY#15 DATA NOTES:

1. All measurements from Intersection of the DW shell and vent collar (fillet) welds.

2. Pit depths are average of four readings taken at 01450/90011350 within 1' distance around ground spots. Taken only when remaining wall thickness shown below 0.736".

6 1 DW 5

0 2 a

SHELL 11 10 8 ",

4 4 4 3 4 3 4 0 "9

FIGURE ( 15 )

OCLR0020718

S Nuclear Calcuation Sheet Subject Calc No. Rev. No. Sheet No.

OQ& Drvwell Ext. Ot Evaluatio inSandbed C-1302-187-5320-024 0 33 of 54 Originator Date Reviewed by Date MARK YEKTA 01/12/93 S. C Tumminelli 04/16/93

5.0 CALCULATION

UT EVALUATION:

BAY # 17:

The outside surface of this bay is rough, similar to bay 1, full of uniform dimples comparable to the outside surface of golf ball. The shell appears to be relatively uniform in thickness except for a band 8 to 10 inches wide approximately 6 inches below the vent header reinforcement plate. The upper portion of the shell beyond the band exhibits no corrosion where the criginal red lead primer is still intact.

Eleven locations were selected to represent the thinnest areas based on the visual observations of the shell surface (Fig. 17). These locations are a deliberate attempt to produce a minimum measurement. Table 17-a shows readings taken to measure the thicknesses of the dry-well shell using a D-meter. The results indicate that all of the areas have thickness greater than the 0.736 inches, except one location. Location 9 as shown in Table 17-a, has a reading below 0.736 inches.

Observations indicate that this location is very deep and not more than 1 to 2 inches in diameter. The depth of area relative to its immediate surroundings was measured at 8 locations around the spot and the average is shown in Table 17-a. Using the general wall thickness acceptance criteria described earlier, the evaluation thickness for location 9 was found to be above 0.736 inches as shown in Table 17-b.

Given the UT measurements, a conservative mean evaluation thickness of 0.900 inches is estimated for this bay and therefore, it is concluded that the bay is acceptable.

OCLR00020719

uclear Calculation Sheet

5.0 CALCULATION

UT EVALUATION:

BAY # 17 (Continued):

Bay #17 UT Data Table 17-a Location UTAverage -

Measuremlent Micrometer 1 0.926 2 1.150--

3 0.898 ---

4 0.951 ---

5 0.913 ---

6 0.992 ---

7 0.970 ---

8 0.990 ---

9 0.720 0.351 10 0.830 ---

I1 0.770 ---

Summary of Measurements Below 0.736 Inches Table 17-b f

tca~~ T M~uremn M~win:(2.)U E 9 0.722O" O.351-OCLR00020720

MNuclear Calculation Sheet NOTES:

I -W1 Tnwasursments ihor in1taf Isitio of IhN DW 2- P~t depth&are averaoe of lour reading a taksn atI O/45"WUM'35bwithin V dlutianv wround gruund spots. rakan cmiy when~ romm.in~fg whil th1Ctkr~se wfll NoOW 0.736.

.2 DW 11 10 i,

SHELL I °1 41 4

4 1, FIGURE ( 17 )

O0CLR00020721

Mj EMINuclear Calculation Sheet 510 CALCULATION:

UT EVALUATION:

BAY # 19:

The outside surface of this bay is rough and very similar to bay 17. Locations 1 through 7 as shown in Table 19, were ground carefully to minimize loss of good metal.

The shell surface is full of dimples comparable to the outside surface of a golf ball. This observation is made by the inspector who located the thinnest areas for the UT examination. The shell appears to be relatively uniform in thickness. Ten locations were selected to represent the thinnest areas based on the visual observations of the shell surface (Fig. 19). These locations are a deliberate attempt to produce a minimum measurement. Table 19 shows readings taken to measure the thicknesses of the drywell shell using a D-meter.

Theresults indicate that all of the areas have thickness greater than the 0.736 inches.

Given the UT measurements, a conservative mean evaluation thickness of 0.850 inches is estimated for this bay and therefore, it is concluded that the bay is acceptable.

Bay #19 UT Data Table 19 Location' 'UTAvag

.l~ea~rerent Microme~ter, (Inches) (Iriche'a 1 0.932 2 0.924 ---

3 0.955 ---

4 0.940 ---

5 0.950 ---

6 0.860 7 0.969 8 0.753 ---

9 0.776 ---

10 0.790 OCLROO020722

EM) uclear Calculation Sheet NOTES:

1. All WSMMeur4MI5 from Iitesrevclion of the OIW aIiaI (butt) and vent coII& it~iIie) Weldsa.

DW I

g

SHELL

.1 7o .4 .3 I1-pb 1*W'ca ,IY 6 w ! D j'1

.-UP_ c iL FIGURE ( 19 )

OCLROO020723

APPENDIX A

SUMMARY

OF MEASUREMENTS OF IMPRESSIONS TAKEN FROM BAY #13 OCLR00020724

= Nuclear Cakcylation Sheet Subject Calc No. Rev. No. Sheet No.

OC Drywell Ext. Ot Evaluation un Sandbed C-1302-187-5320-024 32 Originator Date Reviewed by Date MARK YEKTA 01/12/93 S. C. Tummincili The purpose of this appendix is to characterize the depth of typical uniform dimples on the shell surface. This depth is used in acceptance criteria to quantify the evaluation thickness for an area where the micrometer readings are available.

Two locations in bay 13 were selected since bay 13 is the roughest bay. Impressions of drywell shell surface using DMR 503 Epoxy Replication Putty manufactured by Dyna Mold Inc were made. These impressions were about 10 inches in diameter and about 1 inch thick. The UT locations 7 and 10 in bay 13 were identified in each of -hese impression as the reference points. This is a positive impression of the drywell shell surface. The depth of the typical dimples were measuied as follows; READING DEPTH # 10 DEPTH # 7 (Location) (inches) (inches) 1 0.150 0.075 2 0.000 0.110 3 0.200 0.135 4 0.140 0.200 5 0.150 0.000 6 0.040 0.000 7 0.150 0.170 8 0.010 0.205 9 0.134 10 0.145 0.145 11 0.118 0.064 12 0.105 0.200 13 0.125 0.045 14 0.200 0.180 15 0.135 0.105 16 0.100 17 0.175 0.035 18 0.175 0.015 19 0.155 0.190 20 0.175 0.055 21 0.175 0.305 22 0.135 OCLROO020725

OMHuclear Calculation Sheet Subject Calc No. Rlev. No. Sheet No.

O.C Drvwell 8xt. Ut Evaluation in Sandbed C-1302-187-5320-024 4 f5 Originator Date Reviewed by Date MARK YEKTA 01/12/93 S. C. Tumminelli 04/16/93 Location # 10:

Mean Value = 0.131 Standard Deviation = 0.055 Mean Value + One S.D = 0.186 Location # 7:

Mean Value = 0.118 Standard Deviation = 0.082 Mean Value + One S.D = 0.200 Therefore, a value of 0.200 inches was used as the depth of uniform dimples for the entire outside surface of the drywell in the sandbed region.

0CILROD020725

Calculation Sheet APPENDIX B BUCKLING CAPACITY EVALUATION FOR VARYING UNIFORM THICKNESS OCLRO0020727

EMNuclear Calculation Sheet CALCULATION OF BUCKLING MARGIN - REFUELING CASE, NO SAND -

GE OYCR1S&T - UNIFORM THICKNESS t- 0.736 Inch LOAD ITEM PARAMETER UNITS VALUE FACTOR

• • • DRYWELL GEOMETRY AND MATERIALS 1 Sphere Radius, R (in.) 420 2 Sphere Thickness, t (in.) 0.736 3 Material Yield Strength, Sy (ksi) 38 4 Material Modolus of Elasticity, E (ksi) 29600 5 Factor of Safety,. FS 2

• • • BUCKLING ANALYSIS RESULTS 6 Theoretical Elastic Instability Stress, Ste (ksi) 46.590 6.140

• • • STRESS ANALYSIS RESULTS 7 Applied Meridional Compressive Stress, Sm (ksi) 7.588 5.588 (ksi) 4.510 3.300 8 Applied Circumferential Tensile Stress, Sc

• • • CAPACITY REDUCTION FACTOR CALCULATION 9 Capacity Reduction Factor, ALPHAI 0.207 10 Circumferential Stress Equivalent Pressure, Peq (psi) 15.806 11 'X' Parameter, X= (Peq/8E) (d/t)^2 0.087 12 Delta C (From Figure - ) 0.072 13 Modified Capacity Reduction Factor, ALPHA,i,mod 0.326 14 Reduced Elastic Instability Stress, Se (ksi) 15.182 2.001

• • • PLASTICITY REDUCTION FACTOR CALCULATION 0 15 Yield Stress Ratio, DELTA=Se/Sy 0.400 0 16 Plasticity Reduction Factor, NUi 1.000 C- 17 Inelastic Instability Stress, Si = NUi x Se (ksi) 15.182 2.001 C) 0

• ALLOWABLE COMPRESSIVE STRESS CALCULATION C) 18 Allowable Compressive Stress, Sall= SI/FS (ksi) 7.591 1.000 19 Compressive Stress Margin, M=(Sall/Sm -1) x 100% 0(.) 0.0 co

E M Nuclear Calculation Sheet Subject Ca*cNo. Rev. No. Sheet No.

O.C Drywall Ext.-Ut Evaluation rinadbed- C-1n02-187-5320-024_ 0 3 o~f 54 Olginator Date Reviewed by Date MARK YEKTA 01/12/93 S. c. Tumminelli 04/16/93 CALCULATION OF BUCKLING MARGIN - REFUELING CASE, NO SAND GE OCRFSTO1 - UNIFORM THICKNESS t=0.776 Inch LOAD ITEM PARAMETER UNITS VALUE FACTOR

• • • DRYWELL GEOMETRY AND MATERIALS I Sphere Radius, R (in.) 420 2 Sphere Thickness, t (in.) 0.776 3 Material Yield Strength, Sy (ksi) 38 4 Material Modolus of Elasticity, E (ksi) 29600 5 Factor of Safety, FS 2

• BUCKLING ANALYSIS RESULTS 6 Theoretical Elastic Instability Stress, Ste (ksi) 49.357 6.857

• • • STRESS ANALYSIS RESULTS 7 Applied meridional Compressive Stress, Sm (ksi) 7.198 5.588 8 Applied Circumferential Tensile Stress, Sc (ksi) 4.248 3.300

• CAPACITY REDUCTION FACTOR CALCULATION 9 Capacity Reduction Factor, ALPHAI 0.207 10 Circumferential Stress Equivalent Pressure, Peq (psi) 15.697 11 'X' Parameter, X= (Peq/8E) (d/t)A2 0.078 12 Delta C (From Figure - ) 0.066 13 Modified Capacity Reduction Factor, ALPHAi,mod 0.316 14 Reduced Elastic Instability Stress, Se (ksi) 15.583 2.165

• • • PLASTICITY REDUCTION FACTOR CALCULATION 0 15 Yield Stress Ratio, DELTA=Se/Sy 0.410 0

r- 16 Plasticity Reduction Factor, NUi 1.000 17 Inelastic Instability Stress, Si = NUi x Se (ksi) 15.583 2.165 0

0o ALLOWABLE COMPRESSIVE STRESS CALCULATION NJ 18 Allowable Compressive Stress, Sall= SI/FS (ksi) 7.792 1.082

-1 19 Compressive Stress Margin, M=(Sall/Sm -1)x 100% 8.2 (0o

1EJNuclear Calculation Sheet CALCULATION OF BUCKLING MARGIN - REFUELING CASE, NO SAND GPUN EVALUATION FOR UNIFORM THICKNESS t=0.800 Inch USING THICKNESS RATIO LOAD ITEM PARAMETER UNITS VALUE FACTOR

• • • DRYWELL GEOMETRY AND MATERIALS 1 Sphere Radius, R (in.) 420 2 Sphere Thickness, t (in.) 0.800 3 Material Yield Strength, Sy (ksi) 38 4 Material Modolus of Elasticity, E (ksi) 29600 5 Factor of Safety, FS 2

• • • BUCKLING ANALYSIS RESULTS 6 Theoretical Elastic Instability Stress, Ste (ksi) 50.884 7.288 6.857 * (0.800/0.776)^2 = 7.288

• • • STRESS ANALYSIS RESULTS 7 Applied meridional Compressive Stress, Sm (ksi) 6.982 5.588 8 Applied Circumferential Tensile Stress, Sc (ksi) 4.120 3.300

• • • CAPACITY REDUCTION FACTOR CALCULATION 9 Capacity Reduction Factor, ALPHAI 0.207 10 Circumferential Stress Equivalent Pressure, Peq (psi) 15.697 11 'X' Parameter, X= (Peq/8E) (d/t)A2 0.073 12 Delta C (From Figure -) 0.063 13 Modified Capacity Reduction Factor, ALPHA,i,mod 0.311 14 Reduced Elastic Instability Stress, Se (ksi) 15.824 2.266

• • • PLASTICITY REDUCTION FACTOR CALCULATION 0 15 Yield Stress Ratio, DELTA=Se/Sy 0.416 X- 16 Plasticity Reduction Factor, NUi 1.000 17 Inelastic Instability Stress, Si = NUi x Se (ksi) 15.824 2.266 0

0 0 ALLOWABLE COMPRESSIVE STRESS CALCULATION 18 Allowable Compressive Stress, Sall = SI/FS (ksi) 7.912 1.133 19 Compressive Stress Margin, M=(SalI/Sm -1) x 100% 13.3 CD

EEO] uc lear Calculation Sheet Subject Cale No. Rev. No. Sheet No, 0.Q.C )r1well Ext. Ut .Evalu ation In Sandbed C-1302-187-5320-0241 0 4.5 of 54 Odginator Date Reviewed by Date MARK YEKTA 01/12/93 S. C. Tummine!li 04/16/93 CALCULATION OF BUCKLING MARGIN - REFUELING CASE, NO SAND GPUN EVALUATION FOR UNIFORM THICKNESS t=0.850 Inch USING THICKNESS RATIO LOAD ITEM PARAMETER UNITS VALUE FACTOR

• DRYWELL GEOMETRY AND MATERIALS I Sphere Radius, R (in.) 420 2 Sphere Thickness, t (in.) 0.850 3 Material Yield Strength, Sy (ksi) 38 4 Material Modolus of Elasticity, E (ksi) 29600 5 Factor of Safety, FS 2

• • • BUCKLING ANALYSIS RESULTS 6 Theoretical Elastic Instability Stress, Ste (ksi) 54.063 8.227 6.857 * (0.800/0.776)A2 = 7.288

• • • STRESS ANALYSIS RESULTS 7 Applied meridional Compressive Stress, Sm (ksi) 6.571 5.588 8 Applied Circumferential Tensile Stress, Sc (ksi) 3.878 3.300

• • • CAPACITY REDUCTION FACTOR CALCULATION 9 Capacity Reduction Factor, ALPHAI 0.207 10 Circumferential Stress Equivalent Pressure, Peq (psi) 15.697 11 'X' Parameter, X= (Peq/8E) (d/t)^2 0.065 12 Delta C (From Figure - ) 0.057 13 Modified Capacity Reduction Factor,. ALPHA,i,mod 0.300 14 Reduced Elastic Instability Stress, Se (ksi) 16.257 2.474

• • • -PLASTICITY REDUCTION FACTOR CALCULATION 0 15 Yield Stress Ratio, DELTA=Se/Sy 0.428 o

r-16 Plasticity Reduction Factor, NUi 1.000 17 Inelastic Instability Stress, Si = NUi x Se (ksi) 16.257 2.474 0C 0 ALLOWABLE COMPRESSIVE STRESS CALCULATION N) 18 Allowable Compressive Stress, Sall = SI/FS (ksi) 8.128 1.237 19 Compressive Stress Margin, M=(Sall/Sm -1) x 100% 23.7

I

ýNuclear Calculation Sheet APPENDIX C PICTURES SHOWING CONDITION OF THE DRYWELL IN THE SANDBED REGION 0CLR00020732

F1Nuclear W-1 I

Sand Bed Region - Typical condition found on initia' entry 74 C.Z-. ,

Corrosion product on drywell vessel OCLRO0020733

NM uclear Calculation Sheet QC- OrvwelI Ex. Tit Evaluat~ion in S-andbed C-1302-187-5320-024ý Calc %o. Re,,. No. 0 41fS ShodC No.

Subject Orig[i_ lor DateI ' R- wi cd b . , Date MARK YIFKTA 01/1-2/9)3 S. C. rumrnminefli 04/16/91 Bay #13 - D.NW shell showing plug, The plug is located in the middle of the worst cor-roded area ci tne shell The plug showed no sign of corrosion.

Bay #13 - D.N shell showed less prominent "Tub Rinq" than what was seen in other OCLROO0'20-734

Nuclear Calculation Sheet

.4 - .. '~*'

Bay #1 - L~ooking at the worst comiaded area on shell near jent lube collar/ring. The ground spots seen here correspond It UT spoi 20.,21 23 Bay #13 - Lower Mid portion of the DA%,, shell showing UT spot 5.6 and 10. This close up photo shows the roughness of the corruded surface and how each UT spot has been picked up in the deep valleys thereby biasing the rerr aining wall readings to the con-Senzitiv ýidlp OCLROO020735

.1 *~'

t '

z 0

01 Cn A.

00 CD I*

S ay #13 -Looking towards Bay#h1I Upper right corner of 0/W shell. Note 01)-Grinding depth

'13a[ irub Ring' as delineated by marking and 03 locations of UT spots 3,4,13 & 17. The photo on UT spot d11& 2,Q) - A part ol on right (although blurred by flashý shows 1/8 projection of plug.

• reflection)

C)

=Nuclear Calculation Sheet CaIc Nc'. Rcv. N,). N".

SThCCI O0. Drrqoll Ext. Ut Evaluation in 8ade C 7- ý-040 5 of 4 Orgimao~r D~eRevicw~cd by Date MARK YUMAr~

S. , I'n~mVLC~

-~ - - .4

~'. '-~

p Bay #15 Looking towards Bay#17 which has been closed with foam for coating work

Bay #17. Note the typical s irface of the D'W shpl' :-9r I i:al1z7.¢ corroded spot

\'*' '~\

-~

Bay #13 - Looking toward Bay #15 - Lower left corner showing UT spot #7.12 & 16.

This close up has captured the peaks and valleys of the corroded shell in vivid detail.

Later ND _insoTertnr re,,eId n*r!h belv,,een peaks and valleys in the 0.25" - 0.40" 0CLR00020737

'0 -

C)i O ~~Bay #15 Looking t,-,ward Bz. #/13 showing portions of _

r"- ~Bay #15 - Note (fie original lead primer on vent tube OD

0 ~surface. The "Tub Ring" was less prominent on the shell in DM/hl n oceefor fe eoa floedbi O yIbes cbe pt a p rti n i l o w r l ft orn e . A s o ol e/ s a n d / ru s t. T h e c o n c re te flo o r in th is b a y is o n e o f tl it!e oti exces. aoee poto int lower lef Alannenotd bette betr.is o ee dcoinege oe(- od-iigPcanlai . '-

C)presence of lead primer orn vent collar./ring plate, m (ý cratered holes near shell cornier. ., *

"-4 Co.

Nuclear 3.

4 1 '4

~- -.- .. *1~

.1-'- W A

• .7'.

Bay #13 - Looking toward Bay #11 - Lower right corner of D/W shell showing UT spots 9, 10. 18 & 19 Note the location of these spots - all are located in the valleys of the cor-roded surface This ohoto also shows the condition of the concrete floor. It appears Bay #13 - Looking toward Bay #15 - This photo captures the concrete floor condition and a nortion of lower shell corroded surface in very great detail. The floor in this area OCLR00020739

Nuclear Calculation Sheet Finished floor, vessel with two top coats - caulking material applied.

Drain after floor has been refurbished OCLROD020740