View source for RA-09-006, Updated Information Regarding the Results of the Structural Analysis of the Oyster Creek Drywell Shell, Performed in Support of License Renewal

{{Adams
| number = ML092540596
| issue date = 09/09/2009
| title = Updated Information Regarding the Results of the Structural Analysis of the Oyster Creek Drywell Shell, Performed in Support of License Renewal
| author name = Gallagher M
| author affiliation = Exelon Generation Co, LLC, Exelon Nuclear
| addressee name = 
| addressee affiliation = NRC/Document Control Desk, NRC/NRR
| docket = 05000219
| license number = DPR-016
| contact person = 
| case reference number = RA-09-006
| document type = Letter type:RA
| page count = 32
| project = 
| stage = Other
}}

=Text=
{{#Wiki_filter:Michael P. GallagheT, PE            Telephone 610.765.5958 Exelkn. Nudcear Vice President                      www.exeloncorp.com License Renewal Projects            michaelp.gallagher@exeloncorp.com Exelon Nuclear 2o0 Exelon Way KSA/2-E Kennett Square, PA 19348 RA-09-066 September 09, 2009 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 Oyster Creek Generating Station Facility Operating License No. DPR-16 NRC Docket No. 50-219

==Subject:==
Updated Information Regarding the Results of the Structural Analysis of the Oyster Creek Drywell Shell, Performed in Support of License Renewal

==Reference:==
Letter RA-09-010 from Exelon Generation Company LLC to USNRC, 'Results of Three-Dimensional (3D) Structural Analysis of the Oyster Creek Drywell Shell, Associated with License Renewal for Oyster Creek Nuclear Generating Station (TAC No. MC7624)," dated January 22, 2009 In the referenced letter, Exelon Generation Company, LLC provided the NRC with the results of its modern three-dimensional (3-D) structural analysis of the Oyster Creek drywell shell performed by Structural Integrity Associates (SIA), fulfilling an associated license renewal commitment. As part of preparation for an upcoming briefing of an Advisory Committee on Reactor Safeguards (ACRS) subcommittee on this drywell shell analysis, Exelon contracted Dr.
Clarence Miller, a highly experienced expert in the field of structural analysis and the principal author of an ASME Code Case (N-284-1) used in the 3-D analysis, to assist with ACRS meeting preparation activities. Dr. Miller subsequently reviewed the 3-D analysis and identified two simplifying approximations used by SIA that he recommended be changed. While these changes confirm Exelon's conclusion that a significant amount of margin beyond that required by the ASME Code remains for all areas of the drywell shell, Exelon is providing this information to ensure the NRC staff and ACRS have the latest relevant information.
In the area of interest (i.e., the drywell sand bed region), the use of the more precise information identified by Dr. Miller increases the margin between the ASME Code limits and the current drywell shell condition, above that reported in the referenced letter. However, for the upper spherical region of the drywell shell, these changes cause a decrease in the calculated safety factors. Regardless, a significant amount of margin beyond that required by the ASME Code remains for both the sand bed and upper spherical regions of the drywell shell. These conclusions are documented in Addenda to the 3-D Structural Analysis, which are transmitted with this letter.

M. P. Gallagher to USNRC September 9, 2009 Page 2 of 2 Since these simplifying approximations resulted in more margin to the ASME code limits in the sand bed region, we have concluded that the original analysis represents a satisfactory analysis of the margin above the Code required minimum for buckling. Accordingly, Exelon is not revising the 3-D Structural Analysis report it submitted on January 22, 2009.
If you have any questions regarding this update, please contact Mr. John O'Rourke of my staff, at 610-765-5089.
Respectfully, Michael P. Gallagher Vice President, License Renewal Exelon Generation Company

==Attachment:==
Structural Integrity Associates Letter to Exelon, "Oyster Creek Drywell Analysis:
Incorporation of Dr. Miller's Review Comments," dated September 1, 2009 cc:    Regional Administrator, USNRC Region I USNRC Senior Project Manager, NRR - License Renewal USNRC Project Manager, NRR - Project Manager, OCGS USNRC Senior Resident Inspector, OCNGS Bureau of Nuclear Engineering, NJDEP File No. 05040

StructuralIntegrityAssociates, Inc.
3315 Almaden Expressway Suite 24 San Jose, CA 95118-1557 Phone:        408-978-8200 Fax: 408-978-8964 www.structint.com bsmith@structnt.com September 1, 2009 Report No 0006004.407, Rev. 0 Mr. John O'Rourke Exelon Nuclear 300 Exelon Way Kennett Square, PA 19348

==Subject:==
Oyster Creek Drywell Analysis: Incorporation of Dr. Miller's Review Comments

==References:==
: 1. Miller C. D., "Review of Structural Integrity Associates Report 0006004.401, Revision 1, Structural Evaluation of the Oyster Creek Drywell."
: 2. SI Report 0006004.403, Rev. 0, "Structural Evaluation of the Oyster Creek Drywell Summary Report."
: 3. SI Report 0006004.404, Rev. 0, "Oyster Creek Drywell Sandbed Region Wall Thinning Sensitivity Analyses Summary Report."

==Dear Mr. O'Rourke:==

Dr. Miller's review of the Structural Integrity Associates Report on the structural evaluation of the Oyster Creek Drywell (Reference 1) recommended that two simplifying approximations used in the analysis be modified:
: 1. L, the length between supports, used in the calculation of the capacity reduction factor for the spherical shell be based on the arc lengths versus elevation differences.
: 2. The inclusion of the lower beam support as a contributing stiffener for the calculation of the safety factors for the lower spherical shell and the sandbed region.
As these recommendations affect both the SI Reports 0006004.403, Rev. 0 (Reference 2) and 0006004.404, Rev. 0 (Reference 3), the proposed modifications have been applied to both analyses. Addenda to these reports are included in the attachments to this letter.
In summary, the implementation of Dr. Miller's recommendations has resulted in an increase in safety factors in the sandbed region, which is the area of interest. The minimum sandbed region safety factors and the magnitude of the increase are summarized as follows:
Annapolis, MD     Austin, TX   Centennial, CO Cerritos, CA Chattanooga, TN Huntersville, NC Ontario, Canada South Jordon, UT     Stonington, CT    Uniontown, OH 410-571-0861     512-533-9191  303-792-0077   562-402-3076  423-553-1180    704-597-5554     905-829-9817    801-676-0216          860-536-3982      330-899-9753

Mr. John O'Rourke                                                                  September 1, 2009 0006004.407, Rev. 0                                                                        Page 2 of 2 Base Case
* Refueling:       From 3.54 to      3.83; increase of 8.2%
* Flooding:        From 2.02 to      2.12; increase of 5.0%/o Sensitivity Case 1
* Refueling:       From   3.21   to  3'75; increase of 16.8%
* Flooding:        From   2.01   to  2.10; increase of 4.5%
Sensitivity Case 2
* Refueling:       From 3.46     to  3.81; increase of 10.1%
* Flooding:        From 1.98     to  2.07; increase of 4.5%
If you have any questions or comments regarding this letter, please contact one of the undersigned.
Prepared by:                                        Verified by:
09/01/09                                           09/01/09 Soo Bee Kok                     Date               S. S. Tang, P.E.                Date Associate                                          Associate Approved by:
09/01/09 Marcos Legaspi Herrera, P.E. Date Senior Associate Attachments: A. Addenda to SI Report 0006004.403, Rev. 0, "Structural Evaluation of the Oyster Creek Drywell Summary Report."
B. Addenda to SI Report 0006004.404, Rev. 0, "Oyster Creek Drywell Sandbed Region Wall Thinning Sensitivity Analyses Summary Report."
cc: Project File: OC-15Q V     StructuralIntegrity Associates, Inc.

Attachment A Addenda to SI Report 0006004.403, Rev. 0 Structural Evaluation of the Oyster Creek Drywell Summary Report Addenda to Report 0006004.403.RO                            V  StructuralIntegrity Associates, Inc.
Page Al / Al I

==1.0    INTRODUCTION==

As part of the preparation associated with upcoming briefing for the Advisory Committee on Reactor Safeguards (ACRS) on the Oyster Creek Nuclear Power Plant drywell shell analysis, Exelon contracted Dr. Clarence Miller, a highly experienced expert in the field of structural buckling analysis and the author of the ASME Code Case N-284-1, to assist with ACRS meeting preparation activities. In Dr. Miller's review of the analysis, he recommended that two simplifying approximations used in the analysis be modified:
: 1. L, the length between supports, used in the calculation of the capacity reduction factor for the spherical shell be based on the arc lengths versus elevation differences.
: 2. The inclusion of the lower beam support as a contributing stiffener for the calculation of the safety factors for the lower spherical shell and the sandbed regions.
The above recommendations represent a more precise approach of calculating the length L, which is used for the calculation of the capacity reduction factors, and subsequently the safety factors. All these calculations pertain to the buckling evaluations of the drywell shell.
Dr. Miller's recommendations are fully implemented in this addenda to Structural Integrity (SI)
Report 0006004.403.RO. This addenda addresses the Base Case drywell shell buckling analysis.
The contents of this addenda consist of the following sections:
* Section 2.0 consists of the executive summary that provides the results summary and conclusions.
* Section 3.0 provides the detailed calculations of length L, capacity reduction factors, and safety factors.
StructuralIntegrity Associates, Inc.
Page A2 / Al11

2.0    EXECUTIVE 

==SUMMARY==

2.1    RESULT 

==SUMMARY==

The comparison of the safety factors are provided in Table 1.
Table 1: Safety Factor Comparison Refueling Level A/B Original      Revised     Difference     Lloab Region                                                      Allowable Cylindrical             3.39         3.39          0.0%          2.00 Upper         4.27         3.45        -19.2%          2.00 Spherical      Middle         3.60         3.84         6.7%           2.00 Lower          3.60         4.44         23.3%          2.00 Sandbed                3.54          3.83         8.2%          2.00 Flooding Region              Original      Revised     Difference     Level C Allowable Cylindrical             3.46          3.46         0.0%          1.67 Upper         7.57          6.60       -12.8%          1.67 Spherical      Middle         4.76         4.82          1.3%          1.67 Lower          2.22         2.34          5.4%          1.67 Sandbed                2.02         2.12          5.0%          1.67 StructuralIntegrity Associates, Inc.
Addenda to Report 0006004.403.RO Page A3 / A1I

==2.2    CONCLUSION==
S With reference to the safety factor comparison in Table 1, it can be concluded that:
* In the area of interest (i.e., the drywell sandbed region), the use of Dr. Miller's recommendations increases the reported margin between the ASME Code limits and the current drywell shell conditions. The margins are increased by 8.2% and 5.0% for the refueling and the flooding load cases, respectively.
* The recalculation has no effect on the cylindrical shell region. The reported safety factor for the cylindrical shell region remains unchanged.
* The spherical upper shell region is the only region that shows a decrease in the safety factor margin. However, the safety factor for this region is not the lowest, and therefore, is not limiting.
* For all regions, a significant margin beyond that required by the ASME Code remains.
Addenda to Report 0006004.403.RO                                  V     StructuralIntegrity Associates, Inc.
Page A4 /A11

3.0     CALCULATIONS AND RESULTS 3.1     Length L Calculation Cylindrical Shell Center line of star truss insert plate: Elevation 82' 9" [Ref. 3a of SI Report 0006004.403.R0]
Insert Plate O.D.: 5' 3" [Ref. 3p of SI Report 0006004.403.RO]
Bottom of Stiffener: 4-3/8" from the bottom of Insert Plate [Ref. 3p of SI Report 0006004.403 .RO]
Top of the Knuckle: Elevation 71' 10-25/32" [Ref. 3z of SI Report 0006004.403.RO]
Bottom of Stiffener: Elevation 82' 9" - (5' 3")/2 + 4-3/8"  =  80.49' Length L between stiffener (star truss to top of knuckle): 80.49' - 71' 10-25/32" =8.59'= 103" Upper Spherical Shell Bottom of Knuckle : Elevation 65' 2-7/16" [Ref. 3a of SI Report 0006004.403.R0]
Top of upper beam support: Elevation 49' 3" [Ref. 3w of SI Report 0006004.403.R0]
Shell radius, R = 35'-= 420" [Ref. 3ab of SI Report 0006004.403.RO]
Included angle, 0  =  33.00 Arc Length L (bottom of knuckle to upper beam support) = nRRO/180 = 242" Middle Spherical Shell Bottom of upper beam support : Elevation 44' 8" [Ref. 3w of SI Report 0006004.403.RO]
Top of lower beam support : Elevation 21' 5-7/8" [Ref. 3x of SI Report 0006004.403.RO]
Shell radius, R = 35'= 420" [Ref. 3ab of SI Report 0006004.403.RO]
Include angle, 0 = 45.3' (adjusted to include the largest inscribed circle between supports)
Arc Length L (upper beam support to lower beam support) 7rRO/1 80 = 332" Addenda to Report 0006004.403.RO                                          Structural Integrity Associates, Inc.
Page A5 / All

Lower Spherical Shell and Sandbed Top of lower beam support: Elevation 21' 5-7/8" [Ref. 3x of SI Report 0006004.403.RO]
Bottom of Sandbed : Elevation 8' 11-1/4" [Figure 6-2 of SI Report 0006004.403.RO]
Shell radius, R = 35' = 420" [Ref. 3ab of SI Report 0006004.403.RO]
Included angle, 0 = 32.10 (adjusted to include the largest inscribed circle between supports)
Arc length L (lower beam support to concrete floor) = 7rRO/180 = 235"
                                                                 %     StructuralIntegrity Associates, Inc.
Addenda to Report 0006004.403.RO Page A6 / Al l

3.2    Capacity Reduction Factor Results Table 2: Capacity Reduction Factor ReinR                        t          1                        /        C(l Region(in)                 (in)                     M(in)aal Cylindrical         198          0.604        103         9.42      327.81      0.330 Upper       420          0.676       242         14.36         --       0.278 Spherical    Middle      420          0.678       332         19.67         --       0.230 Lower       420          1.160       235         10.65         --       0.333 Above I1V     420          0.826       235         12.62         --       0.301 ByI Below I1'      420          0.826       235         12.62         --       0.301 Above I1V     420          1.180       235         10.56         --       0.335 By3 Below 11'      420          0.950       235         11.76         --       0.314 By5 Above I1V      420          1.185       235         10.53                  0.335 Below I1'     420          1.074       235         11.06         --       0.325 Above I1'     420          1.133       235         10.77         --       0.331 By7 Below I1V      420          1.034       235         11.28         --       0.322 Above I1V     420          1.074       235         11.06         --       0.325 By9 Below I1'      420          0.993       235         11.51         --       0.318 Above 11F     420          0.860       235         12.36         --       0.304 ByII Below I1V     420          0.860       235         12.36         --       0.304 Above I1F     420          0.907       235         12.04         --       0.309 Ba 3   Below I1F     420          0.907       235         12.04         --       0.309 Above 11V     420          1.062       235         11.13         --       0.324 Ba 5   Below 11F     420          0.935       235         11.86         --       0.312 Above 11F     420          0.863       235         12.34         --       0.305 Ba 7   Below I1V     420          0.963       235     111.69            --       0.315 Above 11V     420          0.826       235         12.62         --       0.301 Ba 9   Below I1F     420          0.826       235         12.62         --       0.301 1
Bay I     Local~       420          0.696       235         13.74         --       0.286 Bay 13     Local  ()    420          0.658       235         14.14         --       0.281 1
Bay 15     Local~       420          0.711       235         13.60         --       0.288 Local ()     420          0.663       235         14.08         --       0.282 Bay 17     Local~1      420          0.850       235         12.44         --       0.303 Bay 19     Local~'      420          0.720       235         13.51         --       0.289 Note: (1) The local regions refer to the thinned areas within the individual bays.
Addenda to Report 0006004.403.RO                                             10 Structural Integrity Associates, Inc.
Page A7 / AlI

3.3       Safety Factor Results Table 3: Refueling Buckling Evaluation (except Sandbed Region)
Spherical Region                      Cylindrical Upper      Middle     Lower R, Shell Radius (in)                                     198        420        420        420 t, Wall Thickness (in)                                  0.604      0.676      0.678      1.160 Gy, Yield Strength (ksi)                                 36.3      36.3       36.3       36.3 E, Young's Modulus (ksi)                               29,000     29,000     29,000     29,000 X, Load Factor                                          7.229      9.800     10.652     11.150 a/alL, Capacity Reduction Factor                        0.330      0.278      0.230     0.333 M, Meridional Compressive Stress (ksi)                   3.41       3.91      4.78       4.52 M,Hoop Tension Stress (ksi)                             9.41      2.29       4.61       4.22 Pbar                                                    0.106      0.049      0.098      0.053 ap, Capacity Reduction Factor (due to tensile effect)   0.139      0.074      0.131      0.079 Cm, Modified Capacity Reduction Factor                  0.469      0.352      0.361      0.412 A, Parameter( = amL     Xo/    a)                       0.318      0.372      0.506      0.572
        , Plasticity Reduction Factor                         1.000      1.000      1.000     0.967 Oje, Theoretical Buckling Stress (ksi)                  11.55      13.49      18.37     20.07 SF, Safety Factor                                        3.39      3.45       3.84       4.44 q     StructuralIntegrity Associates, Inc.
Addenda to Report 0006004.403.RO Page A8 / A11

Table 4: Flooding Buckling Evaluation (except Sandbed Region)
Spherical Region                      Cylindrical Upper       Middle    Lower R, Shell Radius (in)                                     198        420         420       420 t, Wall Thickness (in)                                  0.604      0.676      0.678      1.160 Cry, Yield Strength (ksi)                               36.3       36.3        36.3      36.3 E, Young's Modulus (ksi)                               29,000     29,000      29,000    29,000 X, Load Factor                                          9.148     14.704      14.704     7.344 a/alL, Capacity Reduction Factor                        0.330      0.278      0.230      0.333 oM,Meridional Compressive Stress (ksi)                  2.61       2.65        4.73      10.48 M2,Hoop Tension Stress (ksi)                            2.65       6.66        16.15     22.59 Pbar                                                    0.030     0.143       0.345      0.282 ap, Capacity Reduction Factor (due to tensile effect)   0.048     0.171       0.285      0.258 om, Modified Capacity Reduction Factor                  0.378     0.449       0.515      0.591 A, Parameter ( = am X o,/ ay)                           0.249     0.482       0.987      1.253
       , Plasticity Reduction Factor                         1.000      1.000      0.636      0.539 Oe,  Theoretical Buckling Stress (ksi)                  9.02       17.49      22.79      24.53 SF, Safety Factor                                       3.46       6.60        4.82      2.34 Addenda to Report 0006004.403.RO                                              StructuralIntegrity Associates, Inc.
Page A9 / A11

Table 5: Refueling Buckling Evaluation, Sandbed Region Bay l(')    Bay3       Bay5    Bay7  Bay9   Bay 11 Bay 13(1) Bay 15(l) Bay l70) Bay 9(1)
R, Shell Radius (in)                                    420         420       420     420    420    420     420       420      420       420 t, Wall Thickness (in)                                 0.696      0.950      1.074   1.034 0.993   0.860   0.658     0.711    0.663     0.720 Oy, Yield Strength (ksi)                                36.3       36.3       36.3   36.3   36.3    36.3   36.3      36.3      36.3     36.3 E, Youngs Modulus (ksi)                                29,000     29,000    29,000  29,000 29,000 29,000  29,000    29,000    29,000   29,000 k, Load Factor                                         11.584     11.584     11.584 11.584 11.584 11.584  11.584    11.584    11.584   11.584 a/alL, Capacity Reduction Factor                       0.286      0.314      0.325   0.322 0.318   0.304   0.281     0.288    0.282     0.289 o-, Meridional Compressive Stress (ksi)                 5.03       4.74       4.38   4.37   4.13   4.42    4.72      4.76      5.51     5.24 c;2, Hoop Tension Stress (ksi)                          3.82       3.33       3.38   3.45   3.44   3.93    3.96      3.81      4.60     4.02 Pbar                                                   0.079      0.051      0.046   0.048 0.050   0.066   0.087     0.078    0.100     0.081 ap, Capacity Reduction Factor (due to tensile effect)  0.111      0.076      0.070   0.073 0.076   0.095   0.119     0.109    0.133     0.112 xm, Modified Capacity Reduction Factor                0.397      0.390      0.395   0.395 0.394   0.399   0.400     0.397    0.415     0.401 A, Parameter( =cm ko 1 /y)                             0.637      0.590      0.552   0.551 0.519   0.563  0.603      0.603    0.729     0.671
 ,n,Plasticity Reduction Factor                         0.887      0.942      0.996  0.997   1.000  0.979  0.927      0.927    0.797     0.851 Ole, Theoretical Buckling Stress (ksi)                 20.50      20.19      19.94   19.94  18.83  20.02  20.27      20.27    21.10     20.72 SF, Safety Factor                                       4.07       4.26       4.55   4.56   4.56   4.53    4.30      4.26      3.83     3.95 Note: (1) The thickness for these bays corresponds to the localized thinned area.
Addenda to Report 0006004.403.RO                                                                              Structural IntegrityAssociates, Inc.
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Table 6: Flooding Buckling Evaluation, Sandbed Region 1.
Ba-yl_7' . Bay 3.. .[Ba
                                                                      -  -
Bay5              [
4--------------1---------I----.
ay7 Bay9-1 Bay ll Bay 13(1) Bay 15"') Bay 17(1) Bay 19(1) 4-------------------        .........
                                                                                                                                                         .....
                                                                                                                                                           ...-
R, Shell Radius (in)                                     420        420              420                    420    420       420          420        420         420    420 t, Wall Thickness (in)                                  0.696      0.950            1.074                  1.034  0.993     0.860        0.658      0.711       0.663  0.720 Gy, Yield Strength (ksi)                                 36.3      36.3              36.3                   36.3  36.3      36.3          36.3       36.3       36.3    36.3 E, Youngs Modulus (ksi)                                29,000     29,000          29,000                  29,000 29,000    29,000       29,000     29,000      29,000 29,000 X,Load Factor                                           7.162      7.162           7.162                   7.162  7.162     7.162        7.162      7.162       7.162  7.162 ct/alL,  Capacity Reduction Factor                      0.286      0.314           0.325                   0.322  0.318     0.304        0.281      0.288       0.282  0.289 M,MeridionalCompressiveStress(ksi)                      11.78      9.45              9.95                  10.04  10.20     11.18        11.33      10.13       11.43  12.23 o2 , Hoop Tension Stress (ksi)                          23.26      19.15            17.54                  18.09  18.81     21.38        20.85      21.09       25.50  21.94 Pbar                                                    0.484      0.292           0.237                   0.253  0.274     0.360        0.459      0.430       0.557  0.441 Up, Capacity Reduction Factor (due to tensile effect)   0.330      0.263           0.235                   0.244  0.254     0.291        0.323      0.315       0.348  0.318 am, Modified Capacity Reduction Factor                  0.616      0.577           0.560                   0.566  0.572     0.595        0.604      0.603       0.630  0.607 A,Parameter(=comXa,/oy)                                 1.432      1.076            1.099                  1.121  1.152     1.313        1.351      1.205       1.421  1.465 1, Plasticity Reduction Factor                          0.494      0.598           0.590                   0.582 0.571      0.523        0.513      0.554       0.497  0.487 Oe,  Theoretical Buckling Stress (ksi)                  25.69     23.36            23.51                   23.66 23.86      24.91        25.16      24.21       25.62  25.91 SF, Safety Factor                                       2.18       2.47             2.36                   2.36   2.34      2.23          2.22       2.39       2.24    2.12 Note: (1) The thickness for these bays corresponds to the localized thinned area.
Addenda to Report 0006004.403.RO                                                                                                      V       StructuralIntegrity Associates, Inc.
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Attachment B Addenda to SI Report 0006004.404, Rev. 0 Oyster Creek Drywell Sandbed Region Wall Thinning Sensitivity Analyses Summary Report Addenda to Report 0006004.404.RO                          C   StructuralIntegrity Associates, Inc.
Page BI /B17

==1.0     INTRODUCTION==

As part of the preparation associated with upcoming briefing for the Advisory Committee on Reactor Safeguards (ACRS) on the Oyster Creek Nuclear Power Plant drywell shell analysis, Exelon contracted Dr. Clarence Miller, a highly experienced expert in the field of structural buckling analysis and the author of the ASME Code Case N-284-1, to assist with ACRS meeting preparation activities. In Dr. Miller's review of the analysis, he recommended that two simplifying approximations used in the analysis be modified:
: 1. L, the length between supports, used in the calculation of the capacity reduction factor for the spherical shell be based on the arc lengths versus elevation differences.
: 2. The inclusion of the lower beam support as a contributing stiffener for the calculation of the safety factors for the lower spherical shell and the sandbed regions.
The above recommendations represent a more precise approach of calculating the length L, which is used for the calculation of the capacity reduction factors, and subsequently the safety factors. All these calculations pertain to the buckling evaluations of the drywell shell.
Dr. Miller's recommendations are fully implemented in this addenda to Structural Integrity (SI)
Report 0006004.404.RO. This addenda addresses the Sensitivity Case 1 and Sensitivity Case 2 drywell shell buckling analyses. The contents of this addenda consist of the following sections:
* Section 2.0 consists of the executive summary that provides the results summary and conclusions.
* Section 3.0 provides the detailed calculations of length L, capacity reduction factors, and safety factors.
Addenda to Report 0006004 .404.RO                                       StructuralIntegrity Associates, Inc.
Page B2 / B 17

2.0    EXECUTIVE 

==SUMMARY==

2.1     RESULT 

==SUMMARY==

The comparison of the Sensitivity Case 1 and Sensitivity Case 2 safety factors are provided in Table 1 and Table 2, respectively.
Table 1: Sensitivity Case 1 Safety Factor Comparison Refueling Region               Original     Revised    Difference    Level A/B
(%)       Allowable Cylindrical             3.34         3.34         0.0%          2.00 Upper         4.27         3.45       -19.2%          2.00 Spherical      Middle         3.60         3.84         6.7%          2.00 Lower          3.39         4.33        27.7%          2.00 Sandbed                3.21         3.75        16.8%          2.00 Flooding Original     Revised    Difference     Level C Region
(%)       Allowable Cylindrical             3.45         3.45         0.0%          1.67 Upper         7.58         6.58       -13.2%          1.67 Spherical      Middle         4.75         4.81         1.3%          1.67 Lower          2.19         2.31         5.5%          1.67 Sandbed                2.01         2.10         4.5%          1.67 Addenda to Report 0006004.404.RO                               V    StructuralIntegrity Associates, Inc.
Page B3 / B 17

Table 2: Sensitivity Case 2 Safety Factor Comparison Refueling Region             Original      Revised     Difference     Level A/B
(%)        Allowable Cylindrical            3.34          3.34         0.0%           2.00 Upper         4.27          3.45       -19.2%           2.00 Spherical      Middle        3.60          3.84         6.7%           2.00 Lower         3.60         4.41         22.5%           2.00 Sandbed               3.46          3.81        10.1%           2.00 Flooding Region             Original      Revised     Difference      Level C
(%)        Allowable Cylindrical            3.45          3.45         0.0%           1.67 Upper          7.56         6.56       -13.2%           1.67 Spherical      Middle        4.75          4.81         1.3%           1.67 Lower         2.19          2.31         5.5%           1.67 Sandbed                1.98         2.07         4.5%           1.67 3     StructuralIntegrity Associates, Inc.
Addenda to Report 0006004.404.RO Page B4 / B 17

==2.2    CONCLUSION==
S With reference to the safety factor comparisons in Table 1 and Table 2, it can be concluded that:
* In the area of interest (i.e., the drywell sandbed region), the use of Dr. Miller's recommendations increases the reported margin between the ASME Code limits and the analyzed drywell shell conditions. The margins are increased by no less than 10.1% and 4.5% for the refueling and the flooding load cases, respectively.
* The recalculation has no effect on the cylindrical shell region. The reported safety factor for the cylindrical shell region remains unchanged.
* The spherical upper shell region is the only region that shows a decrease in the safety factor margin. However, the safety factor for this region is not the lowest, and therefore, is not limiting.
       " For all regions, a significant margin beyond that required by the ASME Code remains.
Addenda to Report 0006004.404.RO                                  V     StructuralIntegrity Associates, Inc.
Page B5 / B17

3.0     CALCULATIONS AND RESULTS 3.1     Length L Calculation Cylindrical Shell Center line of star truss insert plate: Elevation 82' 9" [Ref. 3a of SI Report 0006004.403.R0]
Insert Plate O.D.: 5' 3" [Ref. 3p of SI Report 0006004.403.RO]
Bottom of Stiffener: 4-3/8" from the bottom of Insert Plate [Ref. 3p of SI Report 0006004.403.RO]
Top of the Knuckle: Elevation 71' 10-25/32" [Ref. 3z of SI Report 0006004.403.RO]
Bottom of Stiffener: Elevation 82' 9" - (5' 3")/2 + 4-3/8" = 80.49' Length L between stiffener (star truss to top of knuckle): 80.49' - 71' 10-25/32" =8.59'       103" Upper Spherical Shell Bottom of Knuckle : Elevation 65' 2-7/16" [Ref. 3a of SI Report 0006004.403.RO]
Top of upper beam support: Elevation 49' 3" [Ref. 3w of SI Report 0006004.403.RO]
Shell radius, R = 35'= 420" [Ref. 3ab of SI Report 0006004.403.RO]
Included angle, 0 = 33.00 Arc Length L (bottom of knuckle to upper beam support) = irRO/l180 = 242" Middle Spherical Shell Bottom of upper beam support : Elevation 44' 8" [Ref. 3w of SI Report 0006004.403.RO]
Top of lower beam support : Elevation 21' 5-7/8" [Ref. 3x of SI Report 0006004.403.RO]
Shell radius, R = 35' = 420" [Ref. 3ab of SI Report 0006004.403.RO]
Include angle, 0 = 45.3' (adjusted to include the largest inscribed circle between supports)
Arc Length L (upper beam support to lower beam support)= 7R0/1 80 = 332" Addenda to Report 0006004.404.RO                                    V    StructuralIntegrity Associates, Inc.
Page B6/B17

Lower Spherical Shell and Sandbed Top of lower beam support: Elevation 21' 5-7/8" [Ref. 3x of SI Report 0006004.403.RO]
Bottom of Sandbed : Elevation 8' 11-1/4" [Figure 6-2 of SI Report 0006004.403.RO]
Shell radius, R = 35'= 420" [Ref. 3ab of SI Report 0006004.403.RO]
Included angle, 0 = 32.10 (adjusted to include the largest inscribed circle between supports)
Arc length L (lower beam support to concrete floor) = 7rRO/180 = 235" Addenda to Report 0006004.404.RO                                  V   StructuralIntegrity Associates, Inc.
Page B7 / B17

3.2    Capacity Reduction Factor Results Table 3: Capacity Reduction Factor, Sensitivity Case 1 R              t1 Region             R            (            I          M           R/t      X/(x1L Cylindrical         198         0.604         103        9.42       327.81    0.330 Upper       420         0.676        242         14.36         ---    0.278 Spherical    Middle      420         0.678         332        19.67         ---    0.230 Lower       420          1.160       235         10.65         ---    0.333 Bay 1     Above 11'     420         0.826        235         12.62         ---    0.301 Below 11'     420         0.826        235         12.62         ---    0.301 Bay 3     Above 11'     420          1.180       235         10.56         ---    0.335 Below 11'     420          0.950        235        11.76                0.314 Bay 5     Above 11'     420          1.185        235        10.53         ---    0.335 Below I1'     420          1.074        235        11.06         ---    0.325 Bay 7     Above 11'     420          1.133        235        10.77         ---    0.331 Below 11'     420          1.034        235        11.28         ---    0.322 Above 11'     420          1.074        235        11.06         ---    0.325 Bay 9     Below 11'     420          0.993        235        11.51         ---     0.318 Bay 11    Above ItV 420             0.860         235        12.36         ---    0.304 Below 11'     420          0.860        235        12.36         ---    0.304 Bay 13    Above 11'     420         0.907         235        12.04         ---    0.309 Below 11'     420          0.907        235        12.04         ---    0.309 Bay 15    Above 11'     420          1.062        235        11.13      ___
                                                                                     ---    0.324 Below 11'     420          0.935        235        11.86         ---    0.312 Bay 17    Above 11'     420         0.863         235        12.34      ___
                                                                                     ---    0.305 Below 11'     420          0.963        235        11.69         ---    0.315 Bay 19    Above 11'     420         0.826         235        12.62         ---    0.301 Below 11'     420          0.826        235        12.62         ---    0.301 Bay I      Local(1)     420         0.596         235        14.85         ---    0.273 1
Bay 13     Local( 1     420          0.658        235        14.14         ---     0.281 Bay 15     Local(1)     420          0.711        235        13.60         ---     0.288 Local (1)    420          0.663        235        14.08         ---     0.282 Local 1*)    420          0.850        235        12.44         ---     0.303 Bay 19     Local( 1  f  420          0.720        235        13.51         ---     0.289 Note: (1) The local regions refer to the thinned areas within the individual bays.
Z    StructuralIntegrity Associates, Inc.
Addenda to Report 0006004.404.RO Page B8 / B17

Table 4: Capacity Reduction Factor, Sensitivity Case 2 (hain
                                     ,Region       in)           n         M            R/t         CLX/QlL Cylindrical         1   198        0.604     103         9.42       327.81_        0.330
[Upper 14201                 0.676     242        14.36        --            0.278 Spherical       Middle        420        0.678     332        19.67                      0.230 Lower         420    I   1.160     235        10.65    1     ---         0.333 BAbove 11         420        0.826     235        12.621         ---         0.3011 BaylI        eol'            2                    3 BelowlI'
                       'Abovel' V 420        0.826     235     1 12.62     1     ---     I 0.301 420        1.180     235        10.56                      0.335 Bay 3{
BelowlV         420    i0.950        235        11.76     1---
I   0.314 Bay I
AbovelI'F 1
420        1.185     235    1   10.53          ---         0 o.335
_Below   ll       420        1.074     235        11.06                      0.325 Bay 7      AbovelI1 yBelow I F        420 420 I' 1.133      235 235        10.77 11.28 1      --
                                                                                        ---     1 0.31 0.3 0.322 iBelow
[Above   11' IF      42 420        1.7 0.993     235        11.51    1     --      I032 10.32 AbveIF!         420        0.860     2          12.36           --         0.304 B ay 9 I              I  --------
oBelow I       420        0.860     235        12.36                      0.304 Abovelol'       420        0.907 I   235        12.04          ---     1 0.309 By131 Below 11'       420        0.907     235        12.04    i                 0.309 Bay 15 Abovel'V        420    1 1.062   i   235        11.13          ---         0.324 701 iBelowll'         420    I 0.935   1 235          11.86              1       0.312    1 Ab              420        0.863  " 235         12.34                      0.0 Bay17                                                         _.             "'"   i 0.30517
                        &#xfd;Belowll'        420    1 0.963       235       111.69                      0.315 BAbove l'I        420    i 0.776       235        13.02    I     ---     1   0.295 Bay19       ___
Below
__      eow1V Il'     420 4        O 0.776 I   235 23__1.7    13.02                      0.2865 0.295 1
Bay 1       Local1         420        0.696     235        13.74                  I0.286 Bay 13       Local(1        420        0.658     235        14.14          ---     1 0.281 Bay 15       Local('*       420    1   0711  1   235        13.60                      0.288 Bay l7 Local Loca235 420 420.04T[
0.663 1   235        14.08            ---   10.282
                                                                                        --          01303 Local          420        0.850 1   235        12.44          --
_ Bayl9        Local( 11  1420           0.720     235    113.51                _---  _0.289 Note: (1) The local regions refer to the thinned areas within the individual bays.,
Addenda to Report 0006004.404.RO                                            U StructuralIntegrity Associates, Inc.
Page B9 / B17

3.3       Safety Factor Results Table 5: Refueling Buckling Evaluation (except Sandbed Region), Sensitivity Case 1 Spherical Region                       Cylindrical Upper       Middle    Lower R, Shell Radius (in)                                     198         420         420       420 t, Wall Thickness (in)                                  0.604       0.676       0.678     1.160 oy, Yield Strength (ksi)                                36.3        36.3        36.3       36.3 E, Young's Modulus (ksi)                               29,000      29,000      29,000    29,000 X, Load Factor                                         7.227       9.798      10.651    10.506 ca/a   L, Capacity Reduction Factor                     0.330       0.278      0.230      0.333 oC, Meridional Compressive Stress (ksi)                 3.41        3.91        4.78       4.52
         ;2, Hoop Tension Stress (ksi)                          8.86       2.29        4.61       4.22 Pbar                                                    0.100      0.049       0.098      0.053 ap, Capacity Reduction Factor (due to tensile effect)   0.133      0.074       0.131      0.079 am, Modified Capacity Reduction Factor                  0.463      0.352       0.361      0.412 A IParameter ( = am Xoal/a )                            0.314      0.372       0.507      0.539 m Plasticity Reduction Factor                           1.000       1.000       1.000     1.000 ole, Theoretical Buckling Stress (ksi)                  11.40       13.50       18.39     19.56 SF, Safety Factor                                      3.34        3.45        3.84      4.33 Addenda to Report 0006004.404.RO                                         V     StructuralIntegrity Associates, Inc.
Page B10 /B17

Table 6: Flooding Buckling Evaluation (except Sandbed Region), Sensitivity Case I Spherical Region                       Cylindrical Upper       Middle    Lower R, Shell Radius (in)                                     198         420         420       420 t, Wall Thickness (in)                                 0.604        0.676       0.678     1.160 Gy, Yield Strength (ksi)                                36.3         36.3       36.3      36.3 E, Youngs Modulus (ksi)                                29,000      29,000      29,000    29,000 X, Load Factor                                          9.139      14.664      14.664     7.054 c/M/ L, Capacity Reduction Factor                       0.330       0.278       0.230     0.333 mi, Meridional Compressive Stress (ksi)                 2.61         2.65       4.73      10.50 o, Hoop Tension Stress (ksi)                            2.66         6.66       16.15     22.61 Pbar                                                    0.030       0.143       0.345     0.282 ap, Capacity Reduction Factor (due to tensile effect)   0.048       0.171       0.285     0.258 Qm,  Modified Capacity Reduction Factor                 0.378       0.449       0.515     0.591 A , Parameter ( = am ?, ac / oa)                        0.248       0.480       0.985     1.206 rm Plasticity Reduction Factor                          1.000       1.000       0.637     0.553 (je, Theoretical Buckling Stress (ksi)                  9.02        17.43       22.77     24.22 SF, Safety Factor                                       3.45         6.58       4.81      2.31 Addenda to Report 0006004.404.RO                                         V     StructuralIntegrity Associates, Inc.
Page Bll /B17

Table 7: Refueling Buckling Evaluation (except Sandbed Region), Sensitivity Case 2 Spherical Region                        Cylindrical Upper       Middle    Lower R, Shell Radius (in)                                      198         420         420       420 t, Wall Thickness (in)                                   0.604       0.676       0.678     1.160 oy, Yield Strength (ksi)                                 36.3         36.3       36.3      36.3 E, Youngs Modulus (ksi)                                 29,000      29,000      29,000    29,000 k, Load Factor                                           7.224       9.795      10.649    11.146 a/alL, Capacity Reduction Factor                         0.330       0.278       0.230     0.333 on, Meridional Compressive Stress (ksi)                  3.41         3.91       4.79      4.56 02,  Hoop Tension Stress (ksi)                           8.86         2.29       4.61      4.23 Pbar                                                     0.100       0.049       0.098     0.053 cip, Capacity Reduction Factor (due to tensile effect)   0.133       0.074       0.131     0.079 am,  Modified Capacity Reduction Factor                  0.463       0.352       0.361     0.412 A, Parameter(= am ?o 1 /oy)                              0.314       0.372       0.507     0.577 m Plasticity Reduction Factor                            1.000       1.000       1.000     0.960 Ole, Theoretical Buckling Stress (ksi)                   11.40       13.50       18.39    20.10 SF, Safety Factor                                        3.34         3.45       3.84      4.41 Addenda to Report 0006004.404.RO                                          C     StructuralIntegrityAssociates, Inc.
Page B12 /B17

Table 8: Flooding Buckling Evaluation (except Sandbed Region), Sensitivity Case 2 Spherical Region                       Cylindrical Upper       Middle    Lower R, Shell Radius (in)                                       198       420         420       420 t, Wall Thickness (in)                                   0.604      0.676       0.678     1.160 oTy, Yield Strength (ksi)                                 36.3      36.3        36.3      36.3 E, Young~s Modulus (ksi)                                29,000     29,000      29,000    29,000 X,Load Factor(1)                                         9.127     14.617      14.617     6.992 cL/alL, Capacity Reduction Factor                        0.330      0.278       0.230     0.333 on, Meridional Compressive Stress (ksi)                   2.61      2.65        4.73      10.46 oM,Hoop Tension Stress (ksi)                              2.66       6.66       16.15     22.62 Pbar                                                     0.030      0.143       0.345     0.282 cap, Capacity Reduction Factor (due to tensile effect)   0.048      0.171       0.285     0.258 otto, Modified Capacity Reduction Factor                 0.378      0.449       0.515     0.591 A, Parameter ( = am (x o / oy)                           0.248      0.480       0.982     1.192
         , Plasticity Reduction Factor                          1.000      1.000       0.638    0.558 Ole,  Theoretical Buckling Stress (ksi)                   9.00      17.41       22.75    24.12 SF, Safety Factor                                         3.45       6.56       4.81      2.31 StructuralIntegrity Associates, Inc.
Addenda to Report 0006004.404.RO Page B13 /B17

Table 9: Refueling Buckling Evaluation, Sandbed Region, Sensitivity Case 1 Bay 1(')    Bay 3     Bay5   Bay 7  Bay 9 Bay 11  Bay 13(1) Bay 15(1) Bay 17(') Bay 19(')
R, Shell Radius (in)                                     420         420      420    420    420    420      420       420       420      420 t, Wall Thickness (in)                                  0.596      0.950     1.074  1.034  0.993 0.860     0.658     0.711     0.663    0.720 oy, Yield Strength (ksi)                                36.3        36.3      36.3  36.3   36.3   36.3     36.3      36.3      36.3      36.3 E, Youngs Modulus (ksi)                                29,000      29,000   29,000 29,000 29,000 29,000   29,000    29,000    29,000    29,000 X, Load Factor                                         10.506      10.506   10.506 10.506 10.506 10.506   10.506    10.506    10.506    10.506 a/a lL, Capacity Reduction Factor                       0.273      0.314     0.325 0.322   0.318 0.304     0.281    0.288      0.282    0.289 Ma,Meridional Compressive Stress (ksi                  5.20        4.76      4.38  4.37   4.13   4.42     4.73      4.76      5.51      5.24 02,   Hoop Tension Stress (ksi)                         3.80        3.33      3.38  3.45   3.44   3.93     3.96      3.82      4.60      4.03 Pbar                                                    0.092      0.051     0.046 0.048   0.050 0.066     0.087    0.078      0.100    0.081 Cap, Capacity Reduction Factor (due to tensile effect)  0.124      0.076     0.070 0.073   0.076 0.096     0.119     0.109     0.133    0.112 am, Modified Capacity Reduction Factor                  0.397      0.390     0.395 0.395   0.394 0.400     0.400    0.397      0.415    0.401 A, Parameter (=cm X*o / oy)                             0.598      0.537     0.500 0.500   0.471 0.511    0.547     0.547      0.661    0.609 r1, Plasticity Reduction Factor                         0.932    -  1.000    1.000  1.000  1.000  1.000    1.000     1.000     0.861    0.919
    ,e, Theoretical Buckling Stress (ksi                 20.24       19.50    18.17  18.15  17.09  18.56    19.86     19.86     20.66    20.31 SF, Safety Factor                                       3.89        4.10      4.15  4.15   4.13   4.20     4.20      4.17      3.75      3.88 Note: (1) The thickness for these bays corresponds to the localized thinned area.
V StructuralIntegrity Associates, Inc.
Addenda to Report 0006004.404.RO Page B14/B17

Table 10: Flooding Buckling Evaluation, Sandbed Region, Sensitivity Case I Bay 1(1)         Bay 3                Bay 5             Bay 7        Bay 9      Bayll1 Bay13(l) Bay 150) 1Bayl7IV) Bay               ]9(1)
R, Shell Radius (in)                                               420            420                   420              420          420         420            420        420       420          420 t, Wall Thickness (in)                                           0.596           0.950                1.074             1.034        0.993       0.860         0.658       0.711     0.663        0.720 Oy, Yield Strength (ksi)                                          36.3            36.3                 36.3              36.3         36.3        36.3           36.3       36.3      36.3        36.3 E, Youngs Modulus (ksi)                                         29,000         29,000                29,000            29,000       29,000      29,000        29,000     29,000     29,000       29,000 k, Load Factor                                                   7.054           7.054                7.054             7.054        7.054       7.054         7.054       7.054     7.054        7.054 C/Ac IL, Capacity Reduction Factor                              0.273           0.314                0.325             0.322        0.318       0.304         0.281       0.288     0.282        0.289 M, Meridional Compressive Stress (ksj)                           11.80            9.45                 9.95             10.04        10.20       11.18         11.34       10.13     11.44        12.25 M2,Hoop Tension Stress (ksi)                                    26.08           19.18                17.55             18.10        18.82      21.38          20.85      21.10      25.52        21.96 Pbar                                                             0.634           0.292                0.237             0.253        0.274       0.360         0.459      0.430      0.557        0.442 cXp, Capacity Reduction Factor (due to tensile effect)           0.364           0.263                0.235            0.244         0.255       0.291         0.323       0.315     0.348        0.318 crm, Modified Capacity Reduction Factor                         0.637           0.577                0.560            0.566         0.573       0.595         0.604      0.603      0.630        0.607 A, Parameter (=axm k a,/cr)                                      1.460           1.060                1.083             1.104        1.135       1.293         1.331       1.187     1.401        1.446 i1, Plasticity Reduction Factor                                  0.488           0.605                0.596            0.587         0.577      0.528          0.518      0.559      0.501       0.491 Oe,  Theoretical Buckling Stress (ksi)                           25.88          23.26                 23.41            23.55         23.75      24.78          25.03      24.09      25.49       25.78
                 ......................
SF, Safety Factor            ..................................  --
2.19.-.                             . . . .....--
                                                                           ......----..-.....-......................--.
2.46                 2.35             ......
2.34   ..... . . .2..
2.33             22. .
                                                                                                                                               ._....2.22    J...   .
2.21  ._ ..
2.38
                                                                                                                                                                                  ...
2.23
                                                                                                                                                                                            ... i  2 1
                                                                                                                                                                                                     .10 Note: (1) The thickness for these bays corresponds to the localized thinned area.
Addenda to Report 0006004.404.RO                                                                                                                             V      StructuralIntegrity Associates, Inc.
Page B15 / B17

Table 11 : Refueling Buckling Evaluation, Sandbed Region, Sensitivity Case 2 Bay 1(1)    Bay 3      Bay 5     Bay 7   Bay9   1 Bay ll   Bay 13(1) Bay 15(1) Bay 170')j Bay 19(1)
R, Shell Radius (in)                                    420         420       420       420     420       420       420       420       420    j  420 t, Wall Thickness (in)                                 0.696      0.950      1.074     1.034   0.993     0.860    0.658      0.711     0.663     0.720
   ., Yield Strength (ksi)                               36.3       36.3       36.3      36.3    36.3      36.3     36.3      36.3       36.3      36.3 E, Young's Modulus (ksi)                               29,000     29,000    29,000    29,000  29,000    29,000    29,000    29,000    29,000     29,000 k, Load Factor                                         11.345     11.345    11.345    11.345   11.345   11.345    11.345    11.345    11.345     11.345 cL/aIL,  Capacity Reduction Factor                     0.286      0.314      0.325     0.322   0.318     0.304    0.281      0.288     0.282     0.289 Mn,Meridional Compressive Stress (ksi)                  5.03       4.75       4.38     4.37     4.14      4.42     4.73      4.77       5.51      5.42 M, Hoop Tension Stress (ksi)                           3.82       3.33       3.38      3.45    3.44      3.93     3.96      3.82       4.60      4.13 Pbar                                                   0.079      0.051      0.046     0.048   0.050     0.066     0.087     0.078     0.101     0.083 UP, Capacity Reduction Factor (due to tensile effect)  0.111      0.076      0.070     0.073   0.076     0.096     0.119     0.109     0.133     0.115 Qrn, Modified Capacity Reduction Factor                0.397      0.390      0.395     0.395   0.394     0.400     0.400     0.397     0.415     0.404 A ,Pammeter(=xmk o 1 /oy)                              0.623      0.579      0.541     0.540   0.509     0.552    0.591      0.591     0.715     0.685 11,Plasticity Reduction Factor                         0.902      0.957      1.000000     00o 1.000      0.995     0.941     0.941     0.810     0.837 oje, Theoretical Buckling Stress (ksi)                 20.41      20.12      19.62     19.60    18.47    19.94     20.20     20.20     21.00     20.81 SF, Safety Factor                                       4.06       4.24       4.48     4.48     4.46     4.51      4.27      4.24       3.81      3.84 Note: (1) The thickness for these bays corresponds to the localized thinned area.
I      StructuralIntegrity Associates, Inc.
Addenda to Report 0006004.404.RO Page B16 /B17

I Table 12: Flooding Buckling Evaluation, Sandbed Region, Sensitivity Case 2 Bay 1(1)    Bay3      BayI Bay7 I Bay9          Bayll  lBayl3(') Bay  15(1) Bay 17(1) Bay 19(1)
R, Shell Radius (in)                                     420        420       420    420   1 420         420      420      420        420       420 t, WallThickness (in)                                   0.696      0.950     1.074  1.034     0.993     0.860   0.658     0.711      0.663     0.720 oy, Yield Strength (ksi)                                 36.3      36.3       36.3   36.3     36.3      36.3     36.3     36.3        36.3     36.3 E, Young's Modulus (ksi)                               29,000     29,000    29,000 29,000    29,000    29,000   29,000   29,000     29,000    29,000
 ?,, Load Factor                                         6.965      6.965     6.965  6.965     6.965    6.965    6.965     6.965      6.965     6.965 Capacity Reduction Factor OcL/IL,                                             0.286      0.314     0.325  0.322     0.318     0.304   0.281     0.288      0.282     0.289
   -, MeridionalCompressive Stress (ksi)                 11.79      9.46       9.96  10.05     10.21  . 11.19     11.34    10.14      11.44     12.52 MHoop Tension Stress (ks.                               23.33      19.18     17.55  18.10     18.82    21.38    20.86     21.10      25.53     23.15 Pbar                                                    0.485     0.292      0.237  0.254     0.275    0.360    0.459     0.430      0.558     0.466 Up,  Capacity Reduction Factor (due to tensile effect)  0.331     0.263      0.235  0.244     0.255    0.291    0.323     0.315      0.348    0.325 Cxm, Modified Capacity Reduction Factor                 0.617     0.577      0.560  0.566     0.573    0.595    0.604     0.603      0.630    0.614 A, Parameter (=m X c1 / Oy)                             1.394      1.047     1.070  1.091     1.121     1.278    1.315    1.172      1.384     1.475 TI,Plasticity Reduction Factor                          0.503     0.610      0.601  0.592     0.581  1 0.532    0.522     0.564      0.505    0.485 Oe,  TheoreticalBuckling Stress (ksi)                   25.45     23.18      23.32  23.46     23.66    24.68    24.93     24.00      25.38    25.97
                                     ........ ~~~.......                                 .....    -----
SF, Safety Factor                                       2.16       2.45      2.34    2.33     2.32   1.2.21      2.20     2.37       2.22      2.07 Note: (1) The thickness for these bays corresponds to the localized thinned area.
Addenda to Report 0006004.404.RO                                                                               V    StructuralIntegrity Associates, Inc.
Page B17 /B17}}