ML20058M445

Shroud Repair Hardware Stress Analysis, Rev 1

ML20058M445
Person / Time
Site:	Brunswick
Issue date:	12/31/1993
From:	Fujikawa K, Pyron J, Stevens G GENERAL ELECTRIC CO.
To:
Shared Package
ML20058M441	List: BSEP-93-0227, Forwards Rev 1 to GE Rept GE-NE-523-143-1093, Brunswick Unit 1 Shroud Repair Hardware Stress Analysis, in Response to NRC Request Made at 931130 Meeting Re non-limiting Loads Resulting from Annulus Pressurization Events ML20058M445
References
GE-NE-523-143-1, GE-NE-523-143-1093R1, NUDOCS 9312200330
Download: ML20058M445 (60)

Text

., .- - -. . . .

1 GE-NE 523-143-1093 Revision 1 Class ll DRF 137-0010-6 Brunswick Unit 1 Shroud Repair Hardware Stress Analysis December,1993

• O1 Prepared by: b 8.1GN6 11/5/ O G.L.'Stevens, Senior Engineer .;

Structural Mechanics Projects  ;

k V &lw \%/93 K.K. Fujikawb, Senior Engineer Structural Mechanics Projects  ;

El Oll'u &G 12 /1/91 J.W. Pyron, incipal Engineer Reactor Des n Engineering -

Verified by: _-

I 3!73  !

/J.E. Charnley, Principal Engineer Reactor Design Engineering

_ Approved by: '

P. Mayo, Project Manager Brunswick 1 Shroud Repair Project l 1

@ GENuclearEnergy '

9312200330 931213 n PDR ADOCK 05000325 d P- PDR- i;

}

V GEN &5731GIW3, Av.1 IMPORTANTNOTICEREGARDING CONTENTS OF THIS REPORT Please Read Carefully This report was prepared by General Electric solely for the use of the Carolina Power & Light Company (CP&L). The information contained in this report is believed by General Electric to be an accurate and true representation of the facts known, obtained or provided to General Electric at the time this report was prepared.

The only undertakings of the General Electric Company respecting information in this document are contained in the contract governing this work, and nothing contained in this document shall be

^

construed as changing said contract. The use of this information except as defined bysaid contract, or for any purpose other than that for which it is intended, is not authorized; and with respect to any unauthorized use, neither General Electric Company nor any of the contributors to this document makes any representation or warranty (express or implied) as to the completeness, accuracy or usefu the information contained in this document or that such use of such information may not infringe privately owned rights; nor do they assume any responsibility l for _iability or damage of any may result from such use of such information.

i

GEN &573-1431W3, Rev.1 TABLE OF CONTENTS Page No.

. . . . . . . . . 1-1

1.0 INTRODUCTION

.. . . . . . . . . . . .2-1 2.0 APPLIED LOADS.. .. .. . .. .

........ . . . . . . 3-1 3.0 FINITE ELEMENT MODEL. ..

. . . .3-1 3.1 180 Shell and Sub-Structure Finite Element Model...

. . . 4-1 4.0 ANALYSIS AND RESULTS . .

4-2 4.1 Load Case Type #1: Evaluation of Upset Condition .. . . . . . .

4.2 Load Case Type #2: Evaluation of Emergency Condition... . . . 4-16 4.3 Load Case Type #3: Evaluation of Faulted Condition. .. . . . . . . . . 4-25

. . . .. . .4-34 4.4 Evaluation of Shroud Gross Deformation. .. . . .

. . . . . . . . . . . . 5-1 5.0

SUMMARY

AND CONCLUSIONS. . . . . . . . . . .

. . . . . . . . . . . . .6-1

6.0 REFERENCES

~-

GENE 573-143 fW3, &v.1 l LIST OF FIGURES _

Pace No._

.. . . . 2-3 Figure 1-1: Brunswick 1 Shroud Configuration. . . . . . . . .

. . .. . . .... . .... .. . . . . . 2-4 Figure 1-2: Shroud Repair Bracket Assembly . . . . .

.3-4 Figure 3-1: 180' Shell and Sub-structure Finite Element Model- Shroud Portion.

Figure 3-2: 180 Shell and Sub-structure Finite Element Model - Repair Bracket Portion 3-5

. .3-6 Figure 3-3: Boundary Conditions Used to Simulate Bolted Connection...

Figure 3-4: 180 Shell and Sub-structure Model With Boundary Conditions Applied . . 3-7 4 14 Figure 4-1: Upset Condition - Loads Applied to Model..

.4-15 Figure 4-2: Stress Intensity Distribution in Shroud Due to Upset Condition.

_. 4-23 Figure 4-3: Emergency 1 Condition - Loads Applied to Model. . . . . . . .

.4-24 Figure 4-4: Stress Intensity Distribution in Shroud Due to Emergency 1 Condition .

. . . .. . 4-32 Figure 4-5: Faulted Condition - Loads Applied to Model.. .

4-33 Figure 4-6: Stress intensity Distribution in Shroud Due to Faulted Condition..

.4-36 Figure 4-7: Gross Deformation in Shroud Due to Upset Condition.. .. ..

. .4-37 Figure 4-8: Gross Deformation in Shroud Due to Emergency Condition.. ..

. . . . .4-38 Figure 4-9: Gross Deformation in Shroud Due to Faulted Condition..

iii

GENESFS16IW3, Av.1 LIST OF TABLES Pace No.  ;

.2-2 Table 2-1: Applied Loads. . . . .

Table 3-1: Material Properties. . . . . . . . . . . 3-3

. .... . . .. . . 3-3 Table 3-2: Allowable Stress Values. . .. ..

.4-5 Table 4-1: Specified Bolt Preloads. . . . . .

Table 4-2: Relative Joint Motion Evaluation for Upset Condition . . . .. .. .., . .4-6 Table 4-3: Bolt Stress Evaluation for Upset Condition . . .. .. .. . 4-8 Table 4-4: Bolt Bearing and Thread Shear Stress Evaluation for Upset Condition. . .4-12 Table 4-5: Repair Bracket Stress Evaluation for Upset Condition. . .. .. . 4-13 Table 44: Bolt Stress Evaluation for Emergency 1 Condition. . .. .. .4-18 Table 4-7: Bolt Bearing and Tear-Out Stress Evaluation for Emergency 1 Condition.. .4-20

.4-22 Table 4-8: Repair Bracket Stress Evaluation for Emergency 1 Condition. .

. . 4-27 Tabe 9: Bolt Stress Evaluation for Faulted Condition..

Table 4-10: Bolt Bearing and Tear-Out Stress Evaluation for Faulted Condition.. . .. 4-29

. 4-31 Table 4-11: Repair Bracket Stress Evaluation for Faulted Condition.. . . . . . . .

Table 4-12: Maximum Displacement of Lower Shroud .. . . . . . . . . .. . 4-35

. 5-2 Table 5-1: Summary of Stress Analysis Results. . . . . .. .. . . . . .

Table 5-2: Summary of Other Analysis Results. . . . . . .. .. ...... 5-3 i

iv  ;

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GEN &573101W3. Rev.1

1.0 INTRODUCTION

During the current refueling and maintenance outage, the vessel in-service inspection identified crack indications on the shroud at Brunswick Steam Electric Plant, Unit 1 (BSEP-1).

Several of these indications were located in the proximity of the H2 and H3 shroud welds, which are shown in Figure 1-1. The cracking was subsequently verified by ultrasonic l

examination and metallographic examination from boat samples removed from the shroud. As a result of the extent of the cracking, a repair was designed for implementation on the shroud.

The repair fixture designed for the shroud is shown in Figure 1-2. The repair consists of a block that is bolted to the lower shroud by two stepped bolts. The lower bolts have a 3" diameter shank portion that penetrates the shroud and repair block, followed by a 2.75"-12 UN-2A threaded portion. The block is also bolted to the upper shroud by two additional stepped bolts. The upper bolts have a 2.6" diameter shank portion that penetrates the shroud and repair block, followed by a 2.50"-8 UN-2A threaded portion. The upper bolts have a 'T-shaped" head to allow installation from the outside of the shroud due to interferences present from the top guide and core spray spargers. Washers are used at each of the upper bolt locations to ensure intimate contact occurs as a result of bolt preload between the contacting ,

surfaces of the repair bracket and the shroud.

The top guide support ring is " straddled" by the "opair block fixture, and the upper and lower shroud assemblies are effectively " clamped" together. The purpose of the repair hardware is to structurally replace the H2 and H3 welds (identified in Figure 1-1). Welds H2 and H3 were required to support the core top guide and shroud head both horizontally and vertically. Twelve of the repair bracket assemblies will be equally spaced around the circumference of the shroud'(i.e., one every 30 of circumference).

This report presents the detailed stress analysis performed for the repair assembly, The stress including the stresses induced in the shroud by the repair bracket assembly.

analysis is conducted consistent with the load categorizations and stress limits specified in Reference 1.

The main purpose of the analysis is to assess the design and performance requirements for the repair bracket assembly. The stresses in the repair bracket assembly 1-1

GEN &5731431W3, Rev. I were determined as a result of installed preload, seismic, and plant operational loads to ensure they remain below the allowable levels identified in Reference 1 for long term plant operation. In addition, stresses induced in the shroud as a result of the installed bracket assembly were compared to allowable values. The details of the analysis and the results are '

presented herein.

Revisions made to the original release of this report are marked by bars ir the right-hand margin.

?

1-2

GENESB143-IW3, Rev.1 Figure 1-1: Brunswick 1 Shroud Configuration Shroud Head Flange '*'d lik: N. Weld H1

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GENE 573401W3,&v i 'j 2.0 APPLIED LOADS i

The applied loads which the repair bracket and the adjacent shroud must be capable of withstanding are defined in Reference 1 at the H3 weld location. Those loads are defined in terms of total force, moment and pressure values for the following conditions: ,

Condition Description Upset Operating Basis Earthquake (OBE) + Upset Pressure + Weight Emergency 1 Design Basis Earthquake (DBE) + Normal Pressure + Weight j Emergency 2 Main Steam Line Loss of Coolant Accident (LOCA) + Weight Faulted DBE + LOCA + Weight The Reference 1 loads are repeated here in Table 2-1 for convenience. These loads were used to derive equivalent loads for application to the shroud model based on static equilibrium for each of the above conditions. All of the loading was applied at the shroud head interface, except for the portion of the shear loading due to the fuel and top guide, which was applied at the top guide elevation of the shroud. Annulus pressurization loads were ,

considered but were found not to be limiting with respect to the shroud repair; as a result, they i are not included in this analy ;

• The resulting loads described here were applied to the finite element model (FEM) described in Section 3.0 and used throughout the stress analysis for assessing the structural adequacy of the repair bracket assembly.

1 1

2-1 l l

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g5 y & W 143 I W 3. RCV I Table 2-1: Applied Loads (from Reference 1)

Load Upset Emergency 1 Emergency 2 Faulted Component Condition Condition Condition Condition Fs 261.8 367.7 0 367.7 .

Fy 191.2 152.0 642.0 655.5 '

M 26,260 34,610 0 34,610 AP 11.8 10.0 29.0 29.0 Note: Fn = horizontal force (kips)

Fy= vertical force (kips)

M = moment (in-kips)

AP = differential pressure across the upper shroud (psi)

(The higher pressure is inside the shroud. The vertical force due to AP is included in Fy.)

i 2-2

GEN &573-143-1W3, Rev.1 3.0 FINITE ELEMENT MODEL A detailed finite element model of the BSEP-1 shroud and repair bracket assembly was developed for stress analysis purposes to fully evaluate all of the loading conditions specified in Reference 1. The model consisted of a 180 shroud segment composed of shell, beam and spar elements. Repair bracket assemblies were also included in this model; these assemblies were modeled in detail using sub-structuring techniques. A 180 segment was necessitated by the need to evaluate the non-symmetric loads specified in Reference 1. Additionally, this model wn used to simulate and evaluate bolt preload conditions on the shroud and repair bracket. This model is described in detail in the section which follows.

3.1 180 Shell and Sub-Structure Finite Element Model The complete 180 shell and sub-structure finite element model is shown in Figures 3-1 and 3-2. This model was created using the ANSYS finite element computer program (Reference 2). Dimensions for the shroud were obtained from Reference 3, and those for the repair bracket and top guide were obtained from the Reference 4 drawings. The upper and lower shroud portions of the model are comprised of quadrilateral shell elements (STlF 63).

The shroud head support ring and the repair bracket bolts were approximated using three dimensional (3-D) beam elements (STIF 4). The top guide was approximated using 3-D beam and spar elements (STlF 8) for the cross-ties. These components of the model are shown in Figure 3-1. The block was separately modeled using 3-D brick elements with rotational degrees of freedom (STIF 73). The repair bracket portion of the model is shown in Figure 3-2.

The repair bracket model was reduced to a sub-structure (super element) and joined to the shroud model. Contact surfaces between the block, the lower shroud and the upper shroud were simulated using combination (gap) elements (STIF 40). These elements allow separation (e.g., no force transmittal) to occur as needed between the two mating surfaces, while providing force transmittal between the surfaces during contact. The gap elements were intended to prevent motion of the repair bracket beyond the shroud surface, as well as to facilitate the determination of normal forces during bolt preload conditions.

Based on previous experience with modeling bolted joints, the bolt connection points were defined by separate but coincident nodes that were coupled to the shroud and repair 3-1

GENE 52161W3. kv. I bracket. The ends of the repair bracket bolts were coupled in all directions to the appropriate f nodes in the shell (shroud) portions of the model as well as the appropriate nodes in the sub-structure (repair bracket). In addition, the bolt nodes coincident with the contacting surface of i

the repair bracket were coupled in the vertical and circumferential directions to simulate the guiding effect of the hole on the bolt, as shown in Figure 3-3.

The top guide support ring was not modeled since no structural support from the H2 and H3 welds was included per Reference 1. The top guide was coupled in the radial  !

direction from the 90 to 180 at points which corresponded to the top guide wedge locations; these were the only locations assumed to transmit load for transverse shear loading. The lower shroud was modeled long enough to ensure end effects did not influence stresses in the regions of interest.

Constant material properties evaluated at a temperature of 550 F (from References 5 and 6) were utilized in the stress analysis, as shown in Table 3-1. Material allowable stress values utilized in the stress analysis were as shown in Table 3-2. Symmetric boundary conditions were applied to the plane of symmetry of the model, and the bottom of the model was restrained from motion in all directions. For the upset event, the repair bracket and shroud mating surfaces were coupled in the shroud vertical and circumferential directions so that sliding of the two parts relative to each other would not occur. The inherent assumption made here was that the friction force resulting from bcP. preload was not overcome to allow relative motion between the repair bracket and sh oud surfaces. This assumption was checked as a part of the evaluation which follows. A plot of the model with all applied boundary conditions is shown in Figure 3-4.

Due to the relatively small difference between the coefficient of thermal expansion for each of the materials (maximum difference = 0.5x104 in/in *F), and the small temperature gradients present in the region where the repair brackets will be installed, the thermal stresses were judged to be small and were therefore not considered in this analysis.

3-2

GENF573143-IW3, &v.1 Table 3-1: Material Properties  ;

Coefficient of Young's Thermal Density 1 Poisson's Modulus 1 Expansion 1 Component Material (Ib/ft3) Ratio 1 (psi) (in/in *F)

Upper Shroud 304 SS 0.2857 0.2872 25.60x106 9.45x104 Lower Shroud 304 SS 0.2857 0.2872 25.60x106 9.45x104 Repair Bracket A182, 316L2 0.2836 0.3100 25.60x106 9.50x104 Bolts A479, XM-19 0.2857 0.2872 25.60x106 8.98x104 Top Guide 304 SS 0.2857 0.2872 25.60x106 9.45x104 Notes: 1. All values- are taken from References 5 and 6 and are evaluated at a temperature of 550 F.

2. This material possesses the minimum strength properties of the three materials considered for the repair bracket. The actual bracket material is A182 Type 304L.

Table 3-2: Allowable Stress Values ,

Sm @ 550*F Sy@ 100*F. Sy@ 550*F ,

Component Material (ksi) (ksi) (ksi}

Upper Shroud 304 SS 16.95 3_0.00 18.80 Lower Shroud 304 SS 16.95 30.00 18.80 Repair Bracket A182,316Li 13.95 25.00 15.45  ;

Bolts A479, XM-19 29.45 55.00 32.65 Notes: 1. This material possesses the minimum strength properties of the three materials l considered for the repair bracket. The actual bracket material is A182 Type 304L. ,

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BRUNSWICK SHROUD REPAIR

GENESB1431M1, Rev 1 Figure 3-3: Boundary Conditions Used to Simulate Bolted Connection Bolt (3 elements)

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GEN &5731431W3, Rcv.1 4.0 ANALYSIS AND RESULTS The loads identified in Section 2.0 were applied to the finite element model created for the repaired shroud configuration which is described in Section 3.0. In order to demonstrate structural adequacy of the repair to the requirements defined in Reference 1, three types of load cases were run. These load case types are identified below:

Load Case Type No. Applied Loadina Purpose 1 Upset Evaluate Upset Condition 2 Emergency Evaluate Emergency 1 & 2 Conditions 3 Faulted Evaluate Faulted Condition Load case #1 included the effects of bolt preload to verify that preload was maintained and no relative motion occurred during the Upset event. Load cases #2 and #3 did not consider bolt preload, so all of the primary loads transmitted between the repair bracket and the shroud were conservatively assumed to be carried entirely by the bolts, as would be the case for a bolted joint which has separated. The results of an independent investigation revealed that for this assumption, primary stresses in the shroud and repair bracket were equal to or higher than the case where bolt preload was included. Therefore, this scenario was used to determine bounding stresses since there is no requirement for no relative motion during an Emergency or Faulted event.

Simplified hand calculations were also performed to determine bearing and tear-out  !

stresses in the shroud and repair bracket as a result of repair bracket installation for the l limiting loading condition. The stresses resulting from these calculations were well within allowable values, thus demonstrating structural acceptability of the shroud and repair bracket j with respect to local bolting stresses. l The finite element stress analysis details and results for each of the load cases identified above are provided in the sections which follow.

l 4-1 -l l

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. GENE 573143151, &v 1 4.1 Load Case Type #1: Evaluation of Upset Condition Two upset load cases were analyzed: (1) minimum bolt preload and (2) maximum bolt preload. The minimum preload case was used to confirm that relative movement between the upper and lower shroud will not occur during an upset event (i.e., the repair bracket will not slip). The maximum preload case was used to evaluate maximum stresses in the shroud and  ;

repair bracket assembly.

The 180 shell and sub-structure FEM provides an adequate model for applying the necessary non-symmetric load for this condition, as well as an adequate mesh for determining detailed stress distributions throughout the structure.

4.1.1 Minimum Bolt Preload Evaluation A plot of the FEM with the Upset loading applied is shown in Figure 4-1. As a first step in evaluating this condition, minimum bolt preload had to be established in the FEM. To accomplish this, a negative temperature was assigned to the 3-D beam elements simulating the four bolts in each of the repair bracket assemblies. Due to thermal expansion (or, in this case, thermal contraction) effects, the bolt elements " shrink" with the negative temperature input, thus simulating tightening of the bolts. It was not known a priori what applied bolt temperature would be necessary to induce the required minimum preload; therefore, an ,

iterative approach was taken until the resulting force in the bolt elements equated the end-of-life minimum preload of the repair bracket bolts. The end-of-life minimum preload values for the bolts were determined as follows:

Upper Bolts: Initial Minimum Preload = 88,000 lb (see Table 4-1)

Relaxation = 5% (Reference 1)

End-of-life Minimum Preload = 88,000 (0.95) = 83.600 lb Lower Bolts: Initial Minimum Preload = 120,000 lb (see Table 4-1)

Relaxation = 35% (Reference 1)

End-of-life Minimum Preload = 120,000 (0.65) = 78.000 lb After several iterations, the forces in the bolt elements converged to within 1% of these end-of-life minimum preload values. Using the appropriate temperature determined for the bolt elements to simulate preload, the model was again run including the loads for the Upset condition applied to the FEM to establish the minimum bolt preload case for evaluating 4-2 -

J

l GENESB143-1W3. Rev. I relative joint motion. Verification that relative joint motion did not occur for this loading condition is demonstrated in Table 4-2 for the limiting bracket location only. ]

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l 4.1.2 Maximum Bolt Preload Evaluation

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The same process described above for the minimum bolt preload evaluation was followed to establish the maximum bolt preload case for evaluating maximum stresses. For this case, the maximum bolt preload values shown in Table 4-1 were used without the effects ,

of relaxation. A stress intensity plot showing the stress distribution within the FEM for the Upset condition (including maximum bolt preload) is shown in Figure 4-2.

Stress Intensities in the Shroud Since the shroud was modeled using thin shell quadrilateral elements, it was difficult to separate primary membrane stresses from secondary bending and peak stresses. Therefore, the primary stresses reported for the shroud conservatively include some secondary and peak stresses.

The maximum primary local stress intensity, Pi , induced in the shroud as a result of the Upset loading condition was 6.04 ksi compared to the Pmallowable stress of Sm = 16.95 ksi.

The bending stresses in the shroud were classified as secondary, so the primary local plus bending stress intensity, Pi + P 3, was also 6.04 ksi compared to the allowable stress of 1.5S m

= 25.43 ksi.

The range of primary plus secondary stress intensity, Pi + Pb + Q, was conservatively calculated to be 49.32 ksi as compared to the allowable value of 3Sm = 50.85 ksi. These values include the gross structural discontinuity effects of the bolt holes and some peak stress.

Bolt Stresses Detailed calculation of the stresses in the bolts for this load condition is shown in Table 4-3. Bearing stresses for the bolts and the resulting shroud tear-out stresses are shown in Table 4-4.

Another case was evaluated where it was assumed that bolt preload was lost and the loads between the repair bracket assemblies and the shroud were carried entirely by the 4-3,

GENES &96IW3, Rcv.1  !

bolts. The maximum primary plus secondary membrane stress intensity, Pm + O m , in any of the bolts for this case was 18.34 ksi as compared to the allowable of 0.9Sy = 29.39 ksi. The maximum membrane plus bending stress intensity, P m + Pb + Om + 0 3, in any of the bolts for this case was 37.69 ksi as compared to the allowable of 1.2S y = 39.18 ksi. Thus, this case demonstrates that even if joint separation were to occur, the bolt allowables will not be exceeded.

Repair Bracket Stress intensities Stress intensities in the repair bracket as obtained from this run are compared to the appropriate allowables in Table 4-5. Based on a review of all bracket positions, as well as multiple locations within the limiting bracket and gross structural discontinuity effects of the bolt holes, the maximum stress intensities shown in Table 4-5 were obtained from a ,

linearization of stresses through the limiting location of the repair bracket with the maximum stresses.

Based on the collective results presented in this section, it is seen that all of the allowables for the Upset condition are fully satisfied.

l l

4-4 l

1

GENE-5& toim3, &v.1 Table 4-1: Specified Bolt Preloads Bolt Location Maximum (Ib) Minimum (Ib)

Upper 111,000 88,000 Lower 148,000 120,000 ,

4-5

d GENE 573143IW3. Rtv.1 Table 4-2: Relative Joint Motion Evaluation for Upset Condition (Minimum Preload, Limiting Block Position = 150 )

Coefficient of friction, p = 0.5 UPPER RIGHT PART OF BLOCK GAP FY FZ Minimum Bolt Preload = 88,000 lb ELEMENT F-normal NODE

-9401.71 51662 9048.85 -738.30 Relaxation = 5%

3054 1378.43 519.81 Preload

• Relaxation = 83,600 lb 3056 -454.34 51783 3055 -7116.65 51788 7213.48 1249.66 3052 0.00 51794 2326.93 431.54 FEM Bolt Loads:

3051 -11678.50 51810 4032.18 1204.18 Element Force 3047 -18496.58 51917 -3459.68 -371.84 2918 -86301.6 lb 3049 0.00 51919 935.61 817.81 2919 -86301.6 lb 3048 -6438.65 51931 -404.93 1355.13 2920 -86301.6 lb

-8378.55 51998 7178.54 -3120.00 F-average: -86,302 lb 3053 3050 -15363.23 52040 3342.47 -5257.52

-13324.16 52206 -4531.44 -4413.36 FY, FZ Vector Sum 3046 Totals: -90,652.36 27,060.45 -8,322.89 28,311 lb UPPER LEFT PART OF BLOCK GAP FZ Minimum Bolt Preload = 88,000 lb ELEMENT F-normal NODE FY

-8327.90 51623 -9343.22 2751.59 Relaxation = 5%

3036 83,600 lb 3035 -5953.98 51655 -9186.69 1525.13 Preload

• Relaxation =

3039 -10054.2.2 51719 -10818.04 -1744.88 3043 -19897.21 51761 -748.66 1797.93 FEM Bolt Loads:

3038 -1085.76 51831 -1612.06 1451.39 Element Force 3037 -6054.82 51835 -6399.31 4237.51 2921 -86013 lb 3041 0.00 51838 -906.28 1465.43 2922 -86013lb 3040 -12968.18 51851 -3903.18 5268.80 2923 -86013lb 3045 0.00 51881 951.41 1642.34 F-average: -86,013 lb 3044 -8460.14 51891 550.76 4678.80 3042 -10615.12 52178 -8320.68 -2956.86 FY, FZ Vector Sum Total Vector Sum Totals: -83,417.33 -49,735.97 20,117.17 53,650 lb 81,962 lb Check for clippage:

Sum of F-average = 172,315 lb p*F-average = 86,157 lb Vector sum < p*F-average so no relative motion.

44

GEN &5731431W3, Rev 1 Table 4-2: Relative Joint Motion Evaluation for Upset Condition (cont'd)

- (Minimum Preload, Limiting Block Position = 150*)

Coefficient of friction, p = 0.5 LOWER RIGHT PART OF BLOCK GAP ELEMENT F-normal NODE FY FZ Minimum Bolt Preload = 120.000 lb '

-3559.04 50235 518.50 5268.59 Relaxation = 35%

3182 3185 -4584.30 50362 2608.54 -4272.22 Preload

• Relaxation = 78,000 lb 3187 -13999.23 50363 8293.27 -591.31 3183 -18261.78 50368 2609.69 -4961.06 FEM Bott Loads.

3186 -7885.37 50390 4230.07 -2028.81 Element Force '

3180 -15428.88 50664 -5308.37 -2101.36 2924 -80453.5 lb 3178 -899.12 50665 -462.42 -1944.69 2925 -80453.5 lb 3179 -3501.35 50671 -1028.52 -3747.89 2926 -80453.6 lb 3188 0.00 51047 922.76 1155.83 F-average: -80,454 lb 3181 -539.52 51146 534.25 22.31 [

3184 -15715.15 51196 4274.01 2265.87 FY, FZ Vector Sum  ;

Totals: -84,373.72 17,191.78 -21,471.91 27,506 lb LOWER LEFT PART OF BLOCK t GAP FY FZ Minimum Bolt Preload = 120,000 lb ELEMENT F-normal NODE

-7003.24 2811.04 Relaxation = 35% .

3169 -7577.96 50522

-1325.74 50525 236.40 -3366.96 Preload

• Relaxation = 78,000 lb 3171 3167 0.00 50526 -733.22 -278.60 3172 -21544.27 50543 -1973.82 -3014.53 FEM Bolt Loads:

3168 -917.23 50545 -2791.25 272.09 Element Force i

-18692.41 50620 10408.15 -1532.08 2927 -82025 lb 3176 3174 -1419.60 50621 2061.58 -2829.30 2928 -82025 lb

-5828.05 50627 5187.08 -3496.36 2929 -82025 lb 3175 0.00 50746 -2634.15 4811.25 F-average: -82,025 lb 3170 3173 -14835.06 50872 -1236.04 5726.38 3177 -4209.33 51044 5803.46 170.53 FY, FZ Vector Sum Total Vector Sum  ;

Totals: -76,349.65 7,324.95 -726.55 7,361 lb 34,867 lb Check for slippage:

Sum of F-average = 162,478 lb p*F-average = 81,239 lb Vector sum < p*F-average so no relative motion.

t t

I J

4-7 ,

1 1

GENE 573143-1W3, Rev.1 i

)

Table 4-3: Bolt Stress Evaluation for Upset Condition j (Maximum Preload) .j MEMBRANE (Pm + Qm) l Upper Bolts Basic Ecuation:

Stress intensity (SI) = SQRT { (Faxial/Ashank)2 + 4*(Flat'+Fvert')/Ashank' }

Sy = 32,650 psi Faxial = Axial Tensile Bolt Force Allowable = 0.9'Sy = 29,385 psi Flat = Lateral Shear Bolt Force (Sm = 29,450 psi) Fvert = Vertical Shear Bolt Force My & Mr = Bolt Applied Moments  !

Shank Ashank = 4.685 in' Location Faxial (Ibs) Flat (ibs) Fvert (Ibs) My (Ib-in) Mz (It> in) SI/ Allowable 0*+ 112535 3394 -5843 5409 7871 0.823 30*+ 112231 -684 -4357 4386 1813 0.818 0.832  !

30'- 112891 -6805 -6835 5962 -13247 60*+ 112094 -4500 -1829 2215 -3657 0.817 ,

60*- 113235 -8696 -6483 5262 -16758 0.837 90*+ 113032 -3049 2693 -1641 -2263 -0.823

-14229 0.829  :

90* - 113263 -5339 -4123 2620 120'+ 113778 -1713 6062 -4612 -47 0.832 120*- 113475 -2078 -497 -864 -10594 0.825 150*+ 114227 -1249 7638 -6339 2185 0.837 150*- 113936 -393 3696 -4248 -7896 0.829 180*- 114290 615 6878 -6303 -5028 0.836 Maximums: 114,290 -8,696 l 7,638 -6,339 -16,758 0.837 Thread Relief Thread Relief Dia. = 2.313 in. Athread = 4.202 in' Location Faxial (Ibs) Flat (Ibs) Fvert (Ibs) My (Ib-in) Mz (Ib-in) ' SI/ Allowable 0*+ 112535 1197 452 -701 1674 0.912 30*+ 112231 603 95 -609 1529 0.909 30*- 112891 -1843 757 -771 -1834 0.915 60*+ 112094 143 -300 -499 1422 0.908 60*- 113235 -2455 901 -793 -1990 0.918 -l 90*+ 113032 -17 -1022 -301 1384 0.916 i 90*- 113263 -3159 835 -755 -2165 0.919 120'+ 113778 287 -1508 -158 1463 0.922 120'- 113475 -3270 450 -637 -2197 0.921 150*+ 114227 1104 -1568 -125 1665 0.926 150*- 113936 -2931 -313 -432 -2114 0.924 180*- 114290 -2119 -1144 -222 -1914 0.926 Maximums: 114.290 -3,270 -1',568 -793 -2,197 0.926 4-8 i

GEN &573-16IW3, &v.1 Table 4-3: Bolt Stress Evaluation for Upset Condition (cont'd)

(Maximum Preload)

MEMBRANE + BENDING (Pm + Qm + Pb + Qb)

+

Upper Bolts Basic Eaustion:

Stress Intensity (SI) = SQRT { ( Faxial/Ashank + SQRT[My'+Mz')/Zmin )2 + 4(TAUmax')/Ashank2 )

Sy = 32,650 psi Faxial = Axial Tensile Bolt Force Allowable = 1.2*Sy = 39,180 psi Flat = Lateral Shear Bolt Force Fvert = Vertical Shear Bolt Force My & Mz = Bolt Applied Moments Zmin = Minimum Bolt Section Modulus TAUmax = 4/3

• SQRT (Flat' + Fvert')

Shank 4.685 in' Zmin = 1,403 in' Ashank =

Location Faxial (Ibs) Flat (Ibs) Fvert (Ibs) My (Ib-in) Mz (ib-in) SI/ Allowable l 3394 -5843 5409 7871 0.793 0*+ 112535 I

-684 -4357 4386 1813 0.701 30*+ 112231 112891 -6805 -6835 5962 -13247 0.890 30'- '

-4500 -1829 2215 -3657 0.692 60*+ 112094

-8696 -6483 5262 -16758 0.950 60*- 113235

-3049 2693 -1641 -2263 0.669 90*+ 113032

-5339 -4123 2620 -14229 0.886 90*- 113263

-1713 6062 -4612 -47 0.710 120'+ 113778 *

-2078 -497 -864 -10594 0.812 120*- 113475

-1249 7638 --6339 2185 0.753 150'+ 114227

-393 3696 -4248 -7896 0.786 -

150*- 113936 114290 615 6878 -6303 -5028 0.776 180*-

114,290 -8,696 7,638 -6,339 -16,758 0.950 Maximums:

Thread Relief Thread Relief Dia. = 2.313 in. Athread = 4.202 in' Zmin = 1.215 in' Flat (Ibs) Fvert (Ibs) My (Ib-in) Mz (ib-in) SI/Aflowable Location Faxial (Ibs) 112535 1197 452 -701 1674 0.722 0+

112231 603 95 -609 1529 0.716 30+

112891 -1843 757 -771 -1834 0.728 30-112094 143 -300 -499 1422 0.713 60+

113235 -2455 901 -793 -1990 0.734 60-113032 -17 -1022 -301 1384 0.717 90+

113263 -3159 835 -755 -2165 0.738 90-113778 287 -1508 -158 1463 0.722 120+

113475 -3270 450 -637 -2197 0.739 ,

120-114227 1104 -1568 -125 1665 0.730 150+

113936 -2931 -313 -432 -2114 0.739 150-114290 -2119 -1144 -222 -1914 0.736 180-114,290 -3,270 -1,568 -793 -2,197- 0.739 Maximums:

4-9 1

4 GENE 573143IW3 Rev.1 Table 4-3: Bolt Stress Evaluation for Upset Condition (cont'd)

(Maximum Preload)

MEMBRANE (Pm + Qm)

Lower Bolts Basic Eauation:

Stress Intensity (SI) = SQRT { (Faxial/Ashank)' + 4*(Flat'+Fvert')/Ashank' }

Sy = 32,650 psi Faxial = Axial Tensile Bolt Force Allowable = 0.9'Sy = 29,385 psi Flat = Lateral Shear Bolt Force (Sm = 29,450 psi) Fvert = Vertical Shear Bolt Force My & Mz = Bolt Applied Moments Shank Shank Diameter = 2.995 in. Ashank = 7.045 in' Flat (Ibs) Fvert (Ibs) My (Ib-in) Mz (Ib-in) SI/ Allowable Location Faxial (Ibs)

O'+ 149323 -3460 3966 5492 2944 0.723 30*+ 148735 -2609 2199 6613 4566 0.719 4077 5011 4616 -1847 0.729 30*- 150352 149143 -2182 -17 7033 4787 0.721 60*+

5155 4099 -1769 0.736 60*- 151695 4311 150086 -510 -1682 6899 4929 0.725 90* +

3409 4610 3990 -2511 0.739 90*- 152625 103 -2795 6457 4891 0.732 120'+ 151516 2638 2706 5240 -3281 0.743 120*- 153666 150'+ 152722 509 -2566 5853 4909 1738 1136 578 5957 -3980 0.744 150*- 154062

-88 -1274 5806 -4433 0.743 180*- 153697 Maximums: 154,062 4,311 5,155 7,033 4,929 0.744 Thread Relief Thread Relief Dia. = 2.630 in. Athread = 5.433 in' Flat (Ibs) Fvert (Ibs) My (Ib-in) Mz (Ib-in) Sl/ Allowable Location Faxial (Ibs) 0*+ 149323 -136 -1092 855 3532 0.936 30*+ 148735 221 -1342 914 3629 0 932 30*- 150352 383 -899 802 -3477 0.942 60*+ 149143 265 -1437 926 3662 0 934 60*- 151695 405 -787 761 -3494 0 950 90*+ 150086 296 -1412 899 3671 0 940 90*- 152625 240 -767 735 -3535 0 956 120'+ 151516 283 -1318 854 3687 0 949 74 -1050 783 -3596 0.963 120*- 153666 150'+ 152722 287 -1188 803 3691 0.957-150*- 154062 -81 -1212 807 -3638 0 965

-179 -1179 794 -3671 0.963 180*- 153697 Maximums: 154,062 405 -1,437 926 l 3,691 0.965 4-10

- - - - - - . _ . _ s

GE-NE5731431W3, &v.1.

Table 4-3: Bolt Stress Evaluation for Upset Condition (cont'd) ,

(Maximum Preload)

MEMBRANE + BENDING (Pm + Om + Pb + Ob)

Lower Bolts Basic Ecuation:

Stress Intensity (SI) = SQRT { ( Faxial/Ashank + SQRT[My'+Mz2 ]/Zmin )' + 4(TAUmax')/Ashank' }

Sy = 32,650 psi Faxial = Axial Tensile Bolt Force Allowable = 1.2*Sy = 39,180 psi Flat = Lateral Shear Bolt Force Fvert = Vertical Shear Bolt Force My & Mz = Bolt Applied Moments Zmin = Minimum Bolt Section Modulus TAUmax = 4/3

• SQRT (Flat' + Fvert')

Shank Shank Diameter = 2.995 in. Ashank = 7.045 in' Zmin = 2.637 in' Flat (Ibs) Fvert (lbs) My (Ib-in) Mz (Ib-in) SI/ Allowable Location Faxial (Ibs) 149323 -3460 3966 5492 2944 0.603 0*+

148735 -2609 2199 6613 4566 0.617 30*+

4077 5011 4616 -1847 0.596 30*- 150352 149143 -2182 -17 7033 4787 0.623 60*+

4311 5155 4099 -1769 0.596 60* - 151695 150086 -510 -1682 6899 4929 0.626 90*+

3409 4610 3990 -2511 0.601 90*- 152625 103 -2795 6457 4891 0.628 120'+ 151516 153666 2638 2706 5240 -3281 0.618 120*-

152722 509 -2566 5853 4909 0.628 150*+

1136 578 5957 -3980 0.628 150'- 154062 153697 -88 -1274 5806 -4433 0.628 180*-

154,062 4,311 5,155 7,033 4,929 0.628 Maximums:

Thread Relief Thread Relief Dia. = 2.630 in. Athread = 5.433 in' Zmin = 1.786 in' Location Faxial (Ibs) Flat (Ibs) Fvert (Ibs) My (Itrin) Mz (Ib-in) lSI/ Allowable

-138 -1092 855 3532 0.754 0+ 149323 148735 221 -1342 914 3629 0.752 30+

150352 383 -899 802 -3477 0.757 30-265 -1437 926 3662 0.755 60+ 149143 405 -787 761 -3494 0.764 60- 151695 296 -1412 899 3671 0.759 90+ 150086 240 -767 735 -3535 0.769 90- 152625 283 -1318 854 3687 0.766 120+ 151516 74 -1050 783 -3596 0.775 120- 153666 287 -1188 803 3691 0.772 150+ 152722

-81 -1212 807 -3638 0.777 150- 154062

-179 -1179 794 -3671 0.776 180- 153697 154,062 405 -1,437 926 3,691 0.777 Maximums:

4-11

GENE 55143-1(B3, Rw 1 Table 4-4: Bolt Bearing and Thread Shear Stress Evaluation for Upset Condition (Maxirnum Preload)'

Upper Bolts Maximum Axial Bolt Loads (@ shank): Faxial = 114,290 lbs Bearina Stresses:

@ Bolt Head (Tee):

Sigma (bearing) = Faxial/ Ahead Ahead = 2.288 in' Sigma (bearing) = 49,952 psi Sy = 18,800 psi (304 SS)

Allowable = 2.7*Sy = 50,760 psi > Sigma (bearing) so O.K.

Thread Shear Stresses:

@ Threads:

Tau (shear) = Faxial/Athread Athread = 8.223 in' Tau (shear) = 13,899 psi Sy = 32,650 psi (XM-19)

Allowable = 0.6*Sy = 19,590 psi > Tau (shear) so O.K.

Lower Bolts -

Faxial = 154,062 lbs Maximum Axial Bolt Loads (@ shank):

Bearina Stresses:

@ Bolt Head:

Sigma (bearing) = Faxial/ Ahead Ahead = 3.531 in' Sigma (bearing) = 43,631 psi Sy = 18,803 psi (304 SS)

Allowable = 2.7*Sy = 50,760 psi > Sigma (bearing) so O.K.

Thread Shear Stresses:

@ Threads:

Tau (shear) = Faxial/Athread Athread = 10.352 in' Tau (shear) = 14,882 psi Sy = 32,650 psi (XM-19)

Allowable = 0.6*Sy = 19,590 psi > Tau (shear) so O.K.

NOTE: Since the bolted joint prevents relative motbn for Upset loadings, there are no bearing or tearout stresses due to shear loading for t is case.

l 4-12 i

GENE 573143IW3, Rev.1 Table 4-5: Repair Bracket Stress Evaluation for Upset Condition (Maximum Preload)

Stress Classification Stress Intensity (ksi) Allowable (ksi)

Pm 6.24 1.0Sm = 13.95 Pm+Ps 10.41 1.5Sm = 20.93 Pm + Ps + Qa 27.74 3.0Sm = 41.85 Notes: a. The value reported here is the total stress range.

1 4-13

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GENE 573461W3, &v.1 l l

4.2 Load Case Type #2: Evaluation of Emergency Condition Both the Emergency 1 and Emergency 2 conditions were evaluated for acceptability.

However, only the results for the F nergency 1 condition are reported here since that condition provided the most limiting stresses. There are no requirements for the bolts to prevent relative motion during this condition. Therefore, bolt preload was not established for evaluating this condition, and relative joint motion was assumed to occur. As a result, all of the load transmitted between the shroud and the repair bracket was conservatively assumed to be carried entirely by the bolts. As stated earlier, this assumption provides bounding results.

A plot of the FEM with the Emergency 1 loading applied is shown in Figure 4-3. A FEM run was made for this case, and the resulting stress intensity distribution is shown in Figure 4-4 for the shroud.

Stress intensities in the Shroud Since the shroud was modeled using thin shell quadrilateral elements, it was difficult to separate primary stresses from secondary bending and peak stresses. Therefore, the primary stresses reported for the shroud conservatively include some secondary and peak stresses.

The maximum primary local stress intensity, Pi , induced in the shroud as a result of the Emergency 1 loading condition was 16.6 ksi compared to the Pmallowable stress of 1.5Sm=

25.43 ksi. The bending stresses in the shroud were classified as secondary, so the primary local plus bending stress intensity, Pi + Pb , was also 16.6 ksi compared to the allowable stress of 2.25Sm = 38.14 ksi.

Per Reference 1, secondary stress intensities are not limited during an Emergency event. To assure that the shroud deflection due to the Emergency event does not exceed the deflection limits specified in Reference 1, an analysis was performed to show that the gross  ;

deformation limits were not exceeded. Section 4.4 contains a description of the evaluation of the deflection of the shroud.

. Bolt Stresses Detailed calculation of the primary stresses in the bolts for this load condition is shown in Table 4-6. Since bolt bending stresses are secondary in nature, they are not reported since 4-16

GFNE5731431W3, Rev.1 there are no limits on secondary stress for this condition per Reference 1. Bearing and shear stresses for the bolts and the resulting bracket tear-out stresses are shown in Table 4-7.

Repair Bracket Stress Intensities Stress intensities in the repair bracket as obtained from the Emergency condition are compared to the appropriate allowables in Table 4-8. The stress intensities shown in Table 4-8 were obtained from a linearization of the maximum stresses through the repair bracket.

Based on the collective results presented in this section, it is seen that an of the allowables for the Emergency 1 condition are fully satisfied. Since these results bound the Emergency 2 condition, the allowables for the Emergency 2 condition are also satisfied.

P h

3 T

t 5

l l

4-17

GENESB16IW3. Av.1 Table 4-6: Bolt Stress Evaluation for Emergency 1 Condition PRIMARY MEMBRANE (Pm)

Upper Bolts .

Basic Eauation:

Stress Intensity (SI) = SQRT { (Faxial/Ashank)* + 4*(Flat'+Fvert')/Ashank' }

Sm= 29,450 psi Faxial = Axial Tensile Bolt Force Allowable = 1.5*Sm = 44,175 psi Flat = Lateral Shear Bolt Force Fvert = Vertical Shear Bolt Force Fmax = SQRT ( Flat' + Fvort')

= Maximum bolt shear force Shank Ashank = 4.685 in' Flat (Ibs) Fvert (Ibs) Fmax (Ibs) SI/ Allowable Location Faxial (Ibs) 1 0*+ 12,391 -12.067 -35,355 37,357 0.360 30*+ 9,545 -24,383 -45,228 51,382 0.499 30'- 13,337 -1,355 -18,231 18,281 0.188 60*+ 5,977 -32,842 -44,055 54,949 0.532 60* - 13,127 -13,647 3,011 13,975 0.149 90*+ 2,819 -31,083 -40,145 50,772 0.491 90*- 11,188 -30,619 25,940 40,130 0.392 120*+ 7,888 -18,626 -21,569 28,499 0.278

-37,560 37,632 53,169 0.515 120*- 6.698 150*+ 14,046 104 -7,047 7,048 0.096 150'- 11,041 -34.210 37,737 50,935 0.495 180*- 15,145 -20,326 23,199 30,844 0.307 Maximums: 15,145 -37,560 -45,228 54,949 0.532 Thread Relief 2.313 in. Athread = 4.202 in" ,

Thread Relief Dia. =

Flat (Ibs) Fvert (Ibs) Fmax (Ibs) SI/ Allowable j Location Faxial (Ibs)

• 0*+ 12,391 1,954 9,339 9.541 0.123 30*+ 9,545 1,186 8,198 8,284 0.103 30*- 13,337 -2,159 8,776 9,037 0.121 60*+ 5,977 238 5,663 5,668 0.069 60* - 13,127 -1,429 6,430 6,587 0.100 90*+ 2,819 -1,698 2,133 2,726 0.033 90*- 11,188 -138 3,353 3,356 0.070 120'+ 7,888 -1,418 -2,872 3.203 0.055 120'- 6.698 -1,118 -2,617 2,846 0.047 150*+ 14,046 104 -7,047 7,04 8 0.107 150*- 11.041 -2,389 -7,368 7.746 0.102 180*- 15.145 -1,464 -8,711 8,833 0.125 Maximums: 15,145 -2,389 9,339 9,541 0.125 l

4-18 i

GENE 573-143-1W3, hv,1 i Table 4-6: Bolt Stress Evaluation for Emergency 1 Condition (cont'd)

PRIMARY MEMBRANE (Pm) l Lower Bolts ,

Basic E_q. uation:

Stress intensity (SI) = SORT { (Faxial/Ashank)' + 4*(Flat'+Fvert')/Ashank' }

Sm = 29,450 psi Faxial = Axial Tensile Bolt Force Allowable = 1.5*Sm = 44,175 psi Flat = Lateral Shear Bolt Force l Fvert = Vertical Shear Bolt Force i

Fmax = SQRT ( Flat' + Fvert')

= Maximum bolt shear force Shank Shank Diametcr = 2.995 in. Ashank = 7.045 in' Location Faxial (Ibs) Flat (Ibs) Fvert (Ibs) Fmax (lbs) SI/ Allowable 0*+ 32,059 -3.863 35,354 35,565 0.251 30*+ 23,171 9,419 11.441 14,820 0.121 30*- 35,487 16,320 52,017 54,517 0.368 60*+ 11,421 19,535 -16,837 25,789 0.170 60* 32,594 26,952 57,881 63,848 0.423 90*

• 5,367 32,057 -41,054 52,088 0.335 90*- 25,821 29,646 55,259 62,709 0.411 120 7,296 31,890 -52,389 61,332 0.395-120*- 22,930 24,295 36,327 43,703 0.290 150*+ 19.678 21,447 -46,286 51,013 0.334 150*- 27,248 12,852 7,482 14,872 0.130 180*- 26,399 -5,179 -23,200 23,771 0.175 Maximums: 35,487 32,057 57,881 63,848 0.423 f

Thread Relief Thread Relief Dia. = 2.630 in. Athread = 5.433 in' Location Faxial (Ibs) Flat (Ibs) Fvert (Ibs) Fmax (Ibs) SI/ Allowable 0*+ 32.059 -921 13,358 13,389 0.174 '

30*+ 23,171 1,950 9,282 9,484 0.125 30*- 35,487- 3,614 15,078 15,505 0.196 60*+ 11,421 3,500 3.297 4,809 0.062 60*- 32,594 0,31;S 13,381 14,831 0.184 90*+ 5,367 3,4t l -1,785 3,926 0.040 t 90*- 25,821 8,813 8,915 12,536 0.150 120"+ 7,296 2,811 -5,081 5,807 0.057 ,

120*- 22,930 8,601 883 8,647 0.120 ,

?

150'+ 19,678 548 -7,743 7,762 0,104 150*- 27,248 5,738 -4,783 7,470 0.129  ;

180*- 26,399 2.537 -7,688 8,096 0.129  !

Maximums: 35,487 8,813 15,078 15,505 0.196 4-19

GENF573143-1W3, kv.1 Table 4-7: Bolt Bearing and Tear-Out Stress Evaluation for Emergency 1 Condition Upper Bolts Maximum Bolt Loads t@ shank): Faxial = 15,145 lbs '

Fmax = 54,949 lbs .

Fiat = 37,560 lbs ,

Bearina Stresses:

@ Bolt Head (Tee): l Sigma (bearing) = Faxial/ Ahead Ahead = 2.288 in" Sigma (bearing) = 6,619 psi ,

Sy = 18,800 psi (304 SS)

Allowable = 1.5*2.7*Sy = 76,140 psi > Sigma (bearing) so O.K.

@ Shroud Hole:

Sigma (bearing) = Fmax/Ashroud Ashroud = 3.938 in' Sigma (bearing) = 13,954 psi Sy = 15,450 psi (316L SS)

Allowable = 1.5*1.5*Sy = 34,763 psi > Sigma (bearing) so O.K.

@ Bracket:

Sigma (bearing) = Fmax/Abracket Abracket = 2.917 in' Sigma (bearing) = 18,838 psi Sy = 15,450 psi (316L SS)

Allowable = 1.5*Sy = 23,175 psi > Sigma (bearing) so O.K.

Tearout Stresses:

@ Bracket (Hole):

Tau (tearout) = Flat /Abracket Abracket = 7.079 in' Tau (tearout) = 5,306 psl Sm = 13,950 psi (316L SS)

Allowable = 1.5*0.6*Sm = 12,555 psi > Tau (tearout) so O.K.

NOTE: The bearing and shear stress allowables are as defined in Section lll of the ASME Code, ,

Sunsection NG,1992 Edition.

t 9

4-20

GEN &S73143-1W3, Rev.1 Table 4-7: Bolt Bearing and Tear-Out Stress Evaluation for Emergency 1 Condition (cont'd)

Lower Bolts Maximum Bolt Loads (@ shank): Faxial = 35,487 lbs Fmax = 63,848 lbs Flat = 32,057 lbs Bearina Stresses:

@ Bolt Head:

Sigma (bearing) = Faxial/ Ahead Ahead = 3.531 in' Sigma (bearing) = 10,050 psi j Sy = 18,800 psi (304 SS)-- i Allowable = 1.5*2.7'Sy = 76,140 psi > Sigma (bearing) so O.K.

@ Shroud Hole:

Sigma (bearing) = Fmax/ Ashroud l 4.493 in' j Ashroud =

Sigma (bearing) = 14,211 psi l Sy = 18,800 psi (334 SS)

Allowable = 1.5*1.5*Sy = 42,300 psi > Soma (bearing) so O.K.

@ Bracket:

Sigma (bearing) = Fmax/Aor';cket ,

I Abracket = 11.95 in' Sigma (bearing) = 5,343 psi 1 Sy = 15,450 psi (316L SS)  !

Allowable = 1.5*Sy = 23,175 psi > Sigma (bearing) so O.K.

Tearout Stresses:

@ Bracket (Hole):

Tau (tearout) = Flat /Abracket Abracket = 26.66 in' Tau (tearout) = 1,202 psi Sm= 13,950 psi (316L SS)

Allowable = 1.5*0.6*Sm = 12,555 psi > Tau (tearout) so O.K.

NOTE: The bearing and shear stress allowables are as defined in Section ill of the ASME Code, Subsection NG,1992 Edition.

1 4-21

GENE 573143Kfi Rev. 9 Table 4-8: Repair Bracket Stress Evaluation for Emergency 1 Condition Stress Classification Stress intensity (ksi) Allowable (ksi)

Pm 10.74 1.5Sm = 20.93 Pm+Ps 19.24 2.25Sm = 31.39 4-22

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GEN &573461W3 &v.1 l

4.3 Load Case Type #3: Evaluation of Faulted Condition 1

As with the Emergency condition, there are no requirements for the bolts to prevent 1 1

relative motion during this condition. Therefore, bolt preload was not established for j

[

evaluating this condition, so relative joint motion was assumed to occur. As a result, all of the load transmitted between the shroud and the repair bracket was conservatively assumed to be carried entirely by the bolts. ,

A plot of the FEM with the Faulted loading applied is shown in Figure 4-5. A FEM run was made for this case, and the resulting stress intensity distribution is shown in Figure 4-6 for the shroud.

Stress intensities in the Shroud Since the shroud was modeled using thin shell quadrilateral elements, it was difficult to separate primary stresses from secondary bending and peak stresses. Therefore, the primary stresses reported for the shroud conservatively include some secondary and peak stresses. ,

i The maximum primary local stress intensity, Pi , induced in the shroud as a result of the ,

Faulted loading condition was 21.26 ksi compared to the Pm allowable stress of 2.0Sm=  !

33.90 ksi. The bending stresses in the shroud were classified as secondary, so the primary local plus bending stress intensity, Pi + Pb, was also 21.26 ksi compared to the allowable stress of 3.0Sm = 50.85 ksi.

Per Reference 1, secondary stress intensities are not limited during a Faulted event.

To assure that the shroud deflection due to the Faulted event does not exceed the deflection limits specified in Reference 1, an analysis was performed to show that the gross deformation limits were not exceeded. Section 4.4 contains a descriptic,n of the evaluation of the deflection of the shroud.

Bolt Stresses Detailed calculation of the stresses in the bolts for this load condition is shown in Table 4-9. Since bolt bending stresses are secondary in nature, they are not reported since there are no limits on secondary stress for this condition per Reference 1. Bearing and shear stresses for the bolts and the resulting shroud tear-cut stresses are shown in Table 4-10.

l l

4-25 j i

GENE 573-16IW3, Rev.1 Repair Bracket Stress Intensities Stress intensities in the repair bracket as obtained from this run are compared to the appropriate allowables in Table 4-11. The stress intensities shown in Table 4-11 were obtained from a linearization of the maximum stresses through the repair bracket.

Based on the collective results presented in this section, it is seen that all of the allowables for the Faulted condition are fully satisfied.

P I

4-26

GENE 573143-1L&7, &v.1 Table 4-9: Bolt Stress Evaluation for Faulted Condition PRIMARY MEMBRANE (Pm)

Upper Bolts Basic Emation:

Stress : tensity (SI) = SORT { (Faxial/Ashank)2 + 4*(Flat'+Fvert')/Ashank' }

Sm = 29,450 psi Faxial = Axial Tensile Bolt Force Allowable = 2.0*Sm = 58,900 psi Flat = Lateral Shear Bolt Force Fvert = Vertical Shear Bolt Force Fmax = SQRT ( Flat' + Fvert')

Maximum bolt shear force Shank Ashank = 4.685 in' Location Faxial (Ibs) Flat (lbs) Fvert (Ibs) Fmax (Ibs) SI/ Allowable 0*+ 15,662 -9,930 -56,420 57,287 0.419 30*+ 13,207 -22,501 -66,559 70,259 0.511 30*- 16,275 -3,621 -39,017 39,184 0.290 60*+ 9,715 -31,280 -65,304 72,409 0.526 60*- 14,772 -15,850 -17,550 23,648 0.180 90*+ 4,707 -29,047 -61,383 67,909 0.492 90*- 12.026 32,763 4,799 33,113 0.244 120'+ 4,250 15,858 -42,303 45,177 0.328 120*- 4,428 -40,121 16,779 43.488 0.316 150'+ 8.244 2,631 -19,861 20.035 0.148 150*- 4.665 -37,028 16,728 40,632 0.295 180*- 9.073 -23,126 2,345 23,244 0.172 Maximums: 16,275 -40,121 -66,559 72,409 0.526 Thread Relief 2.313 in. Athread = 4,202 in' Thread Relief Dia.

Location Faxial (Ibs) Flat (Ibs) Fvert (Ibs) Fmax (Ibs) SI/ Allowable 0*+ 15,662 3.286 12.660 13,080 0.123 30*+ 13,207 2,334 11,644 11,876 0.110 30'- 16,275 -3,626 12,035 12,569 0,121 60*+ 9,715 804 9,208 9,243 0.084 _

60*- 14,772 -3,404 9,738 10,316 0.103 90*+ 4,707 -844 5,119 5,188 0.046 90*- 12.026 -2,082 6,543 6,867 0.074 120'+ 4,250 -1,227 1,366 1,836 0.023 120*- 4,428 2,163 1,772 2,797 0.029 150*+ 8,244 -118 -2,987 2,990 0.041 150* - 4.665 -2,443 -3,159 3,994 0.037 180*- 9,073 -1,457 -4,625 4,849 0.054 Maximums: 16,275 -3,626 12,660 13,080 0.123 4-27

l GENELS143-1W3, Rev.1 Table 4-9: Bolt Stress Evaluation for Faulted Condition (cont'd)

PRIMARY MEMBRANE (Pm)

Lower Bolts Basic Ecuation:

Stress intensity (SI) = SQRT { (Faxial/Ashank)* + 4*(Flat'+Fvert')/Ashank' }

Sm = 29,450 psi Faxial = Axial Tensile Bolt Force Allowable = 2.0*Sm = 58,900 psi Flat = Lateral Shear Bolt Force Fvert = Vertical Shear Bolt Force Fmax = SORT ( Flat' + Fvert')

= Maximum bolt shear force Shank Shank Diameter = 2.995 in. Ashank = 7.045 in' Location Faxial (ibs) Flat (Ibs) Fvert (Ibs) Fmax (Ibs) SI/ Allowable 0*+ 46,133 -4,366 56.420 56.589 0.295 30*+ 37,267 9,169 32,253 33,531 0.185 30*- 49.710 16,954 73,322 75,257 0.382 60*+ 22.270 19,051 3,577 19,384 0.108 60*- 46,232 28.083 79,276 84,103 0.420 90*+ 8,874 30,916 -19,906 36,771 0.179 90*- 36,937 30,894 76,490 82,494 0.407 120*+ 2,768 31,567 -31,316 44,466 0.214 120*- 26,725 24.409 56,841 61,860 0.305 150'+ 11,860 21,594 -25,452 33,378- 0.163 150*- 23,016 12,802 28,585 31,320 0.161 180*- 20,364 2,807 -4,935 5,678 0,056 Maximums: 49,710 31,567 79,276 84,103 0.420 Thread Relief Thread Relief Dia. = 2.630 in. Athread = 5.433 in' Location Faxial (Ibs) Flat (Ibs) Fvert (Ibs) Fmax (Ibs) SI/ Allowable 0*+ 46.133 -1,802 19,698 19,760 0.190 ,

30*+ 37,267 1,117 15,613 15,653 0.152 30*- 49,710 4,524 21.481 21,952 0.207 60*+ 22,270 3.531 9,070 - 9,734 0.092 60*- 46,232 7.111 19,753 20,994 0.195 90*+ 8,874 4,010 2,593 4,775 0.041 90*- 36,937 9,472 15,262- 17,962 0.161 120'+ 2.768 2,798 2,086 3,490 0.023 120*- 26,725 9,895 6,751 11,979 0.112 150'+ 11,860 543 -4,991 5,020 0.049 150*- 23,016 6,835 -1,420 6,981 0.084 -

180*- 20,364 2,807 -4,935 -5.678 0.073 Maximums: 49,710 9,895 21,481 21,952 0.207 4-28

GEN &55143-1W3, &v.1 Table 4-10: Bolt Bearing and Tear-Out Stress Evaluation for Faulted Condition l Upper Bolts Maximum Bolt Loads (@ shank): Faxial = 16,275 lbs Fmax = 72.409 lbs Flat = 40,121 lbs Bearina Stresses: ,

@ Bolt Head (Tee):

Sigma (bearing) = Faxial/ Ahead Ahead = 2.288 in' Sigma (bearing) = 7,113 psi Sy = 18,800 psi (304 SS)

Allowable = 2.0*2.7*Sy = 101,520 psi > Sigma (bearing) so O.K.

@ Shroud Hole:

Sigma (bearing) = Fmax/Ashroud Ashroud = 3.938 in' Sigma (bearing) = 18,387 psi Sy = 15,450 psi (316L SS)

Allowable = 2.0*1.5*Sy = 46,350 psi > Sigma (bearing) so O.K.

@ Bracket:

Sigma (bearing) = Fmax/Abracket Abracket = 2.917 in' Sigma (bearing) = 24,823 psi Sy = 15,450 psi (316L SS)  ;

Allowable = 2.0*Sy = 30,900 psi > Sigma (bearing) so O.K.

Tearout Stresses:

@ Bracket (Hole):

Tau (tearout) = Flat /Abracket Abracket = 7.079- in' Tau (tearout) = 5,668 psi ,

Sm= 13,950 psi (316L SS)

Allowable = 2.0*0.6*Sm = 16,740 psi > Tau (tearout) so O.K.

I NOTE: The bearing and shear stress allowables are as defined in Section 111 of the ASME Code.

Subsection NG,1992 Edition.

4-29

= , -

GEN &573143IW3, &v.1 i l

Table 4-10: Bolt Bearing and Tear-Out Stress Evaluation for Faulted Condition (cont'd) l Lower Bolts Maximum Bolt Loads (@ shank): Faxial = 49,710 lbs Fmax = 84,103 lbs Flat = 31,567 lbs Bearina Stresses:

@ Bolt Head:

Sigma (bearing) = Faxial/ Ahead Ahead = 3.531 in' Sigma (bearing) = 14,078 psi Sy = 18,800 psi (304 SS)

Allowable = 2.0*2.7*Sy = 101,520 psi > Sigma (bearing) so O.K.

@ Shroud Hole:

Sigma (bearing) = Fmax/Ashroud Ashroud = 4.493 in' Sigma (bearing) = 18,719 psi Sy = 18,800 psi (304 SS)

Allowable = 2.0*1.5*Sy = 56,400 psi > Sigma (bearing) so O.K.

@ Bracket:

Sigma (bearing) = Fmax/Abracket Abracket = 11.95 in' Sigma (bearing) = 7,038 psi ,

Sy = 15,450 psi (316L SS)

Allowable = 2.0*Sy = 30,900 psi > Sigma (bearing) so O.K.

Tearout Stresses:

@ Bracket (Hole):

Tau (tearout) = Flat /Abracket Abracket = 26.66 in' Tau (tearout) = 1,184 psi Sm = 13,950 psi (316L SS)

Allowable = 2.0*0.6*Sm = 16,740 psi > Tau (tearout) so O.K.

NOTE: The bearing and shear stress allowables are as defined in Section 111 of the ASME Code,-

Subsection NG,1992 Edition.

4-30

GFNES731431M1. Rev.1 Tabic 4-11: Repair Bracket Stress Evaluation for Faulted Condition Stress Classification Stress Intensity (ksi) Allowable (ksi)

Pm 17.14 2.0Sm = 27.90 P ,,, + P ,, 28.15 3.0S,,, = 41.85 l

l I

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_ _ _ _ _ _ - - - - - - - - *^ - * -- - * ' - - - - - - - - - - - ----- - - - - -

GENE 5731431W3, &v 1 c

i 4.4 Evaluation of Shroud Gross Deformation i

The FEM results from each of the three types of loading conditions evaluated were reviewed to evaluate gross deformation of the shroud and repair bracket assembly during the Upset, Emergency, and Faulted loading conditions. The gross deformation was obtained by adding the maximum shroud deflection to the appropriate relative movement of the shroud due to the seismic event. Table 4-12 shows the maximum allowable shroud deflections for the different loading conditions per Reference 1.

Upset Condition The deformation resulting from the Upset load condition is shown in Figure 4-7. From Figure 4-7, it is seen that the maximum deflection at the top guide elevation of the shroud _;

structure is 0.03 inch plus the relative shroud seismic displacement of 0.31 inch for a total of O.34 inch. This value is below the permitted deflection of 0.93 inch.

Emeroency Conditions The deformation resulting from the worst case Emergency 1 load condition is shown in Figure 4-8. From Figure 4-8, it is seen that the maximum deflection at the top guide elevation of the shroud structure is 0.05 inch plus the relative shroud seismic displacement of 0.51 inch for a total of 0.56 inch. This is below the permitted deflection of 1.40 inches.

Faulted Condition The deformation resulting from the Faulted load condition is shown in Figure 4-9. From Figure 4-9, it is seen that the maximum deflection at the top guide elevation of the shroud structure is 0.05 inch plus the relative shroud seismic displacement of 0.51 inches for a total of 0.56 inch. This is below the permitted deflection of 1.87 inches.

The radial growth of the shroud due to thermal expansion between room temperature and reactor operating temperature is not included as part of the shroud displacements reported here since the entire control rod drive line is also displaced radially. The RPV bottom head, core plate and top guide all move approximately the same amount as a result of thermal growth; therefore, there is no significant differential displacement of the shroud due to thermal expansion.

4-34

I l

GENE-573161W3, &v.1 ^l 1

)

Based on the collective results presented in this section, it is seen that all of the allowables for the deformation are fully satisfied.

l Table 4-12: Maximum Displacement of Lower Shroud Actual Maximum Allowable Maximum Loading Condition Displacement Displacement (inches) (inches)

Upset 0.34 0.93 Emergency 0.56 1.40 Faulted 0.56 1.87 1

4-35

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GENE 551431W3, Rev 1 5.0

SUMMARY

AND CONCLUSIONS l

l A summary of the stress analysis results for the BSEP-1 shroud repair configuration for i the three load cases studied is provided in Tables 5-1 and 5-2. The results show that the repair design is structurally adequate to withstand the loads imposed during planned and projected operating load conditions. It is therefore concluded that the repair design satisfies all of the requirements of Reference 1 and is adequate for permanent, long-term reactor operation as a structural replacement of the shroud H2 and H3 welds.

I r

2 t

5-1 l

4

GENF573-143-tm3, Rw 1 Table 5-1: Summary of Stress Analysis Results Loading Stress Calculated Allowable Condition Component Category Stress (ksi) Stress (ksi)

Upset Shroud Pm 6.04 1.0Sm = 16.95 Pi 6.04 1.5Sm = 25.43 P, + Pb 6.04 1.5Sm = 25.43 P, + Ps + Q 49.32a 3.0Sm = 50.85 Repair Bracket Pm 6.24 1.0Sm= 13.95 Pm+Pe 10.41 1.5Sm = 20.93 Pm + Ps + Q 27.74a 3.0Sm = 41.85 Bolts Pm < 28.36 1.0Sm = 29.45 Pm+O m 28.36 0.9Sy= 29.39 Pm + Ps + Om + On 37.22 1.2Sy = 39.18 Emergency Shroud Pm 16.6 1.5Sm = 25.43 Pi 16.6 2.25Sm = 38.14 P+Ps i 16.6 2.25Sm = 38.14 Repair Bracket Pm 10.74 1.5Sm = 20.93 Pm+Ps 19.24 2.25Sm = 31.39 Bolts Pm 23.50 1.5Sm = 44.18 Faulted Shroud Pm 21.26 2.0Sm = 33.90 Pi 21.26 3.0Sm= 50.85 P, + Ps 21.26 3.0Sm = 50.85 .

Repair Bracket Pm 17.14 2.0Sm = 27.90 Pm+Ps 28.15 3.0Sm = 41.85 Bolts P- 30.98 2.0S ,, = 58.90 Notes: a. The value reported here is the total stress range.

i 5-2 ,

GENE 57J 1G1W3. &v.1 Table 5-2: Summary of Other Analysis Results Requirement Load Condition Calculated Value Allowable Value Relative Joint Motion Upset No motion No motion Shroud Lateral Upset 0.34 0.93 Displacement Emergency 0.56 1.40 Faulted 0.56 1.87 l

l l

f 1

l 5-3 l

1 i

A ** ' GENE 573161m3, Rev.1 -

i

6.0 REFERENCES

l l

[1] GE Design Specification No. 24A5111, Revision 2," Shroud Repair Clamp," GE Nuclear I

Energy, San Jose.

[2] G.J. DeSalvo and R.W. Gorman, ANSYS Engineering Analysis System User's Manual, Swanson Analysis Systems, Inc., Houston, PA, Revision 4.4a, May 1,1989.

[3] Sun Shipbuilding & D.D. Company Drawing No. 42360-3, Revision 2, " Shroud -- Top Section Core Structure, Fabrication Drawing."

[4] GE Drawings:

a. 112D6238, Rev. O, " Bracket," GE Nuclear Energy, San Jose.

b. 137C9909, Rev. O, " Bolt," GE Nuclear Energy, San Jose.

c. 137C9908, Rev. O, " Nut, Hex Head," GE Nuclear Energy, San Jose.

d. 137C9910, Rev. O, " Washer," GE Nuclear Energy, San Jose.

e. 761E769, Rev. 3, " Top Guide," GE Nuclear Energy, San Jose.

[5] ASME Boiler and Pressure Vessel Code, Section ll, Part D, " Material Specifications,"

1992 Edition, ASME, New York.

[6] "GE BWR Plant Materials Handbook," GE Nuclear Energy, San Jose,1993.

6-1