ML20092C809

Rev 2, Shroud Repairs Program for Dresden Units 2 & 3, Back-up Calculations for RPV Stress Rept Number 25A5691, May 1995

ML20092C809
Person / Time
Site:	Dresden
Issue date:	05/12/1995
From:	Herlekar A GENERAL ELECTRIC CO.
To:
Shared Package
ML20091F935	List: ML20092C737 ML20092C771 ML20092C780 ML20092C809 ML20092C828 ML20092C845 ML20092D229
References
FOIA-95-188 GENE-771-77-119, GENE-771-77-1194-R02, GENE-771-77-1194-R2, NUDOCS 9509130144
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O GENE-77177-1194 GE PROPRIETARY INFORMATION Revision 2 DRF B13-01749 i

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SHROUD REPAIRS PROGRAM FOR i

DRESDEN UNITS 2 & 3 i

Back-up Calculations for RPV Stress Report No. 25A5691

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l May,1995 i

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Prepared By:

s ey k.T. Herlekar, Senior Engineer Mechanical Design Engineering Verified By:

b. bN B. N. Sridhar, Senior Engineer Mechanical Design Engineering

, E!/dYS Approved By:

R. P. Svarney, GE froject Manager Dresden Shroud Repairs Project 9509130144 950830 PDR FOIA IRWIN95-188 PDR Dresden 2 & 3 RPV Stress Report Backup Calculations Page 1

'O GENE-771-77-1194 GE PROPRIETARY INFORMATION Revisico 2 DRF Bl3-01749 PROPRIETARY INFORMATION NOTICE This document contains proprietary information of General Electric Company and is furnished to Commonwealth Edison in confidence solely for the purpose or purposes stated in the transmittal letter. No other use, direct or indirect of the document or the information it contains is authorized. The recipient shall not publish or otherwise disclose it or the informadon to others without written consent of General Electric, and shall return the document at the request of General Electric.

IMPORTANT NOTICE REGARDING CONTENTS OF THIS REPORT The only undertakings of General Electric Company respecting information in this document are contained in the contract between Commonwealth Edison (Comed) and General Electric Company, and nothing contained in this document shall be construed as changing the contract.

The use of this information by anyone other than Comed, or for any purpose other than that for which it is intended, is not authorized; and with respect to any unauthorized use, General Electric Company makes no representation or wananty, and assumes no liability as to the completeness, accuracy, or usefulness of the information contained in this document.

Dresden 2 & 3 RPV Stress Repon Backup Calculations Page 2 i

O GENE-77177-Il94 GE PROPRIETARY INFORMATION Revision 2 DRF B13-01749 TABLE OF CONTENTS Subsection No.

Description Page 4

Load path to RPV 9

Summary of Loads on RPV 10 2

RPV Stabilizer Brackets Analysis 13 3

Tie-Rod Loads Calculations 14 Tie-Rod Loads Summary 17 4

Shroud Support System Analysis 24 Shroud Suppon System Stress Summary 25 5

RPV Skirt Analysis 27 RPV Skirt Stress Summary 6

Evaluation for Lateral Spring Loads on RPV 28 Summary of RPV Shell Stresses due to Lateral Loads 31 Evaluation of RPV Shell Stresses due to Tie-Rod Loads32 7

Summary of RPV Shell Stresses due to Tie-Rod Loads 34 8

Evaluation of RPV Shell/Baffic Plate Junction for Tie-Rod Loads35 40 Summary of RPV Shell/ Baffle Plate Junction Stresses 9

Baffle Plate Deflection due to Tie-Rod Loads 42 f

44 10 References ATTACHMENTS (Total 7 pages) 46-52 1

Dresden 2 & 3 RPV Stress Repon Backup Calculations Page 5

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' 3 GENE-771-95-0195, Revision 1

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Dresden Units 2 & 3 - Top Ring Plate and Star Truss Stress Analysis l

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i DRESDEN UNITS 2 & 3

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TOP RING PLATE AND STAR TRUSS STRESS ANALYSIS i

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Prepared by:

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Dresdar 2 & 3 Top Rheg Plate andStar Truss Stren Kalyshr GENE 771-95-0I95, Rev.1 EXECUDVE

SUMMARY

The installation of the proposed shroud modification in Dresden 2 & 3 will result in an increase in the seismic force t ansmitted to the reactor pressure vessel (RPV) and support structure. The members of the support structure, specifically the RPV stabilizer, top ring plate and star truss, are analyzed to determine if the design is sufficient to withstand the increased load. This report presents the detailed stress analysis performed for the top ring plate, RPV stabilizer and star truss.

The results of the stress analysis show that the RPV stabilizer, top ring plate and star truss are capable ofwithstanding the increased loads resulting from the installation of the slunud modification hardware.

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Dresder 2 &.f Top Ring Matt andStar Truss Stress Analys"3 GENE.771 95-0195. Rev.I TABLE OF CONTENTS LO INTRODUCTION I

2.0 TOP RING PLATE STRESS ANALYSIS AND RESULTS.

..2 2.1ASSUMPTlONS...................................................................................................................2 2.2 FINITE ELEMENT MODEL................................................................................................... 2 2.3 STRESS EVALUATION METHODOLOGY.......................................................................... 3 2.4 STRES S E VALUATION RES ULTS........................................................................................... 3 3.0 STAR TRUSS AND RPV STABILIZER STRESS ANALYSIS AND RESULTS 6

3.1 ASSUMPTIONS.....................................................................................................................6 3.2 STRESS C A LCULATIONS...................................................................................................... 6 3.3 STRESS EV ALUATION METHODOLOGY.............................................................................. 7 3.4 STRES S E VALU ATION RES ULTS.......................................................................................... 7 3.5 STRESS EVALUATION RESULTS FOR OTHER COMPONENTS (8)............................................. 7 4.0 CONCLOSIONS.

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5.0 REFERENCES

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1 LIST OF FIGURES FIGURE 2 1: FINITE ELEMENT MODEL FOR TOP RING PLATE STRESS ANALYSIS...................... 4 FIGURE 2-2: VON-MISES STRESS DISTRIBUTION IN TOP RING PLATE....................................... 5 LIST OF TABLES TA B L E 2-1 : M ATERI A L PROPERTIES........................................................................................ 3 I

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Dresden 2 & J Top Rhsg M andStar Tmss Stress Analysis GENE-771-95-0195, Rev. !

1.0 INTRODUCTION

The installation of the proposed shroud modification in Dresden 2 & 3 will result in an increase in the seismic force transmitted to the reactor pressure vessel (RPV) and support structure. The members of the suppon stmeture, specifically the RPV stabilizer, top ring plate and star truss, are analyzed to determine if the design is sufficient to withstand the increased load. This report presents the detailed stress analysis performed for the RPV stabilizer, top ring plate and star truss.

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Dresden 2 & 3 Top Rhet Place andStar Truss Stress A'atysh GENE-771-95-0195, Rev. l 2.0 TOP RING PLATE STRESS ANALYSIS AND RESULTS Stress analysis of the Dresden 2 & 3 reactor pressure vessel (RPV) support structure was performed to evaluate the cJects of the increased seismic loads on the RPV stabilizer, top ring plate and star tmss. The details and results of the stress analysis for the top ring plate are presented in this section.

l 2.1 Assumptions in the top ring plate stress analysis it was assumed that the RPV stabilizers behave like truss members. This assumption is conservative because the stablizers actually behave like beams. A beam structure increases the stiffness and resistance of the structure more than i

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4 2.2 Finite Element Afodel l

The purpose of this model was to perform a. stress analysis of the top ring plate when i

1 subjected to increased seismic loads due to the addition of the shroud modification hardware.

Dimensions for the model were obtained from the drawings specified in Ref. [1]. The complete finite element model is shown in Fig. 2-1.

i The finite element model of the Dresden 2 & 3 top ring plate structure was developed i

using the COSMOS /M, version 1.70 finite element program [2]. COSMOS /M is verified for accuracy by using sample problems and comparing the results with altemate calculations.

4 The sample problems included static analysis problems with similar elements.

A finite element analysis was performed on the top ring plate to evaluate the local effects of the axial and bending loads induced by the RPV stabilizer connection. The model 4

consisted of a quaner section of the structure because of the symmetry of the geometry and loading. The top ring plate was modeled with shell elements. An equivalent moment was distributed among nodes representing the stabilizer bracket. Forces representing the axial load were also applied. The long edges of the plate were fixed and vertical motion was constrained at the locations where the biological shield concrete would act to inhibit the downward vertical motion.

The maximum SSE global forces in the RPV stabilizers were determined in Ref. [3].

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These SSE loads were used to produce the maximum, and therefore most conservative, stress results for the top ring plate. Thejet force from a main steam line break (MSLB) was shown to yield a greater resultant force than a reactor recirculation line break (RRLB) at the location of the support structure [7]. T'aus, the appropriate MSLB jet force was applied to the support I

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Dresden 8 & J Top RJeg nnes and.nwr Tmst Sanns Analysb GENE-771-95.G195, Rev. I structure to yield the most conservative results. The axial load in the RPV stabilizer was taken as half of the faulted condition global force given for the RPV stabilizer,1120 kaps, m addition to half of the main steam line break (MSLB) jet force of 184 kips (7], resulting in a i

load of 652 kips. The stabilizer pretension load of260 kips was subtracted as this load is taken by the sleeve. To determine the effects of the stabilizer eccentric loading, the maximum stabilizer load acting on each stabilizer bracket,392 kips [6], was converted into l

an equivalent moment by using the appropriate lever length, 7 inches. The equivalent i

moment was effectively represented by distributing vertical forces among nodes representing the stabilizer bracket.

Constant material properties evaluated at an operating temperature of 150'F, as shown in Table 2-1, [5], were utilized in the stress analysis.

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Table 2-1 Material Properties i

Symbol Description

-Top Ring Plate j~

-SA 36 p

Density 0.283 lb/in' E

Modulus of Elasticity 29.65 x10' psi v

Poisson's Ratio 0.326 a

Mean Coefficient of 6.57x10'in/in *F Thermal Expansion 2.3 Stress Evalunden Medradology The loads described in Section 2.2 were applied as specified. The stress in the top 1

ring plate was obtained by taking the maximum average stress of the elements in the area of the stabilizer bracket.

2.4 Stress Evaluadon Results The primary finite element analysis indicated the maximum average stress in the top ring plate for the SSE + JET loading condition is 16,052 psi. This stress is below the seismic allowable stress,0.95*F,, of 34,200 psi. The stress distribution in the top ring plate is depicted in Fig. 2-2.

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r Dresden 2 & 3 Top Rheg Plate andStar Truss Stress Acalysis GENE-771-95-0!95. Rev. I 3.0 STAR TRUSS AND RPV STABILIZER STRESS ANALYSIS AND RESULTS Stress analysis of the Dresden 2 & 3 reactor pressure vessel (RPV) support stmeture was performed to evaluate the effects of the increased seismic loads on the RPV stabilizer, top ring plate and star truss. The details and results of the stress analysis for the star truss members, RPV stabilizer and RPV stabilizer bracket welds are presented in this section, 3.1 Assumptions In the star truss, RPV stabilizer and bracket weld stress analysis, it was assumed that the RPV stabilizers and star truss members behave like truss elements. This assumption is conservative.

3.2 Stress Calculations The purpose of this calculation was to perform a stress analysis of the star truss, RPV stabilizer and RPV stabilizer bracket welds when subjected to increased seismic loads due to the addition of the shroud modification hardware. Member properties for the analysis were obtained from drawings specified in Ref. [1]. The complete calculation is given in Ref. [6].

The maximum SSE global force in the star truss was determined in Ref. [3]. This SSE load was distributed according to Ref. [7] to determine the most severely loaded member. This member was analyzed to produce the maximum, and therefore most conservative, stress results for the star truss members. The global force for the star truss was taken as the global force for the faulted condition given in Ref. [3],1610 kips, in addition to j

the MSLB jet force of 229 kips [7] resulting in a load of I839 kips. This load was then distributed in accordance with Ref. [7] to obtain the maximum star truss member axial load of 382.6 kips.

The maximum SSE global forces in the RPV stabilizer were determined in Ref. [3].

These SSE loads were used to produce the maximum, and therefore most conservative, stress results for the stabilizer. The maximum axial load in the RPV stabilizer was taken as half of the global force given for the RPV stabilizer,1120 kips, in addition to half of the MSLB jet force of 184 kips [7], resulting in a load of 652 kips. The pretension load of 260 kips was subtracted from the seismic + jet load to yield a total stabilizer load of 392 kips [6].

The maximum SSE global forces in the RPV stabilizer brackets were determined in Ref. [3]. These SSE loads were used to produce the maximum, and therefore most conservative, stress results for the bracket welds. The maximum axial load in one RPV stabilizer bracket was 392 ki s [6]. The moment induced by the eccentric axial load was p

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Dresden 2 & 3 Top Ring Maar and. Der Tranas.Drens Analysis GENE-771-95-0195. Rev. i calculated by using the appropriate lever length,7 inches, resulting in a moment of 2744 kips-in.

3.3 Stress Evaluadon niethodology he loads described in Section 3.2 were applied as specified. The stress in the star 4

truss was evaluated by dividing the maximum axial load by the area of the member.

He stress in the stabiliar was conservatively calculated by dividing the maximum force in the stabiliar by the area of the tension rod.-

The stress transmitted to the bracket plate and weld was determined from the bending moment, axial load, and the section properties of the plate and weld. The maximum stress in i

the weld was then calculated from the resulting shear and bending stresses as detailed in Ref.

[6].

3.4 Stress Evaluadon Results i

The stress analysis indicated the maximum stress in the star truss for the SSE + JET loading condition is 12,491 psi. This stress is below both the seismic allowable tensile stress of 34,200 psi and the seismic allowable compressive stress of 33,954 psi.

't The stress analysis indicated the maximum stress in the RPV stabiliar for the SSE +

JET loading condition is 47.2 ksi. This stress is below the AISC seismic allowable stress of i

90.0 ksi.

l The stress analysis indicated the maximum stress in the stabiliar bracket plate for the SSE + JET loading condition is 15,7% psi. This stress is below the seismic allowable stress i-of 34,200 psi. The stress analysis indicated the maximum stress in the stabilizer bracket weld for the SSE + JET loading condition is 13,816 psi. This stress is below the AISC i

seismic allowable stress of 28,800 psi.

3.5 Stress Evaluadon Results for Other Components [8]

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The connection of the star truss members to the drywell shear lug was also evaluated in a supplementary calculation.

i The results indicated that the stresses in the stiffener bolting are below the allowable stress limits for the bolting. Thus the stiffener bolts are acceptable.

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. g Dresden 2 & 3 Top Ring Place andStar Truss Stress Acalysk GENE 771-95-0195, Rev.1 The weld and base metal stresses in the stabilizer female shear lug are less than the allowable values and therefore they are acceptable.

The stresses in the stabilizer embedment reinforcement bars are less than the allowable values and thus are acceptable.

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4.0 CONCLUSION

S The results of the stress analysis show that the RPV stabilizer, top ring plate and star truss are capable of with<tanding the increased loads resulting from the installation of the shroud modification hardware.

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5.0 REFERENCES

[1]

Drawings:

a. B-709, Rev. C, " Reactor Drywell Framing Plans El. 575'-2" & 589'-2 1/2","

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Sargent & Lundy Incorporated Engineers, Chicago, IL.

b. B-279, Rev. G, " Reactor Drywell Framing Plans El. 575'-2" & 589'-21/2","

Sargent & Lundy Incorporated Engineers, Chicago, IL.

c. B-706, Rev. D, Sargent & Lundy Incorporated Engineers, Chicago, IL.

d. B-276, Rev. O, Sargent & Lundy Incorporated Engineers, Chicago, IL.

e. I 12C3568, Rev. 2, " Reactor Vessel Stabilizer," GE Nuclear Energy, San Jose, CA.

f.153F765, Rev. 3, " Vessel Stabilizer Erection," GE Nuclear Energy, San Jose, CA.

g. 718E692, Rev. 3, " Biological Shield Wall," GE Nuclear Energy, San Jose, CA.

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[2]

Structural Research and Analysis Corporation, COSMOS /M Version 1.70, Santa f

Monica, CA,1993.

[3]

GE Report GENE-771-85-1194,"Dresden Units 2 & 3 Shroud Repair Seismic Analysis Backup Calculations", GE Nuclear Energy, San Jose, November 1994.

[4]

Commonwealth Edison Company, Updated Final Safety Analysis Report, Dresden i

Station, Section 3.6.2.3.2, Vol.1.

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[5]

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

[6]

GE Report GENE-771-96-0195,"Dresden Units 2 & 3 Top Ring Plate and Star Truss Stress Analysis Backup Calculations," GE Nuclear ~ Energy, San Jose, CA, January 1995.

[7]

Comrnonwealth Edison Company, Updated Final Safety Analysis Report, Dresden Station, Appendix 5A, Vol. 3.

[8]

GENE DRF B13-01749," Comed Shroud Fix for Dresden," May 1995.

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' 4 GENE-771-96-0195, Revision 1 Dresden Units 2 & 3, Top Ring Plate and Star Truss Analysis Backup Calculations General Electric Nuclear Company Proprietary Information A

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