ML13248A348

WCAP-17549-NP, Revision 2 - Monticello Replacement Steam Dryer Structural Evaluation for High-Cycle Acoustic Loads Using ACE, Enclosure 13

ML13248A348
Person / Time
Site:	Monticello
Issue date:	08/29/2013
From:	Han Y, Plonczak G W, Rajakumar C, Salehzadeh A, Suddaby D A, Theuret R C, Wellstein L F Westinghouse
To:	Office of Nuclear Reactor Regulation
References
L-MT-13-091, TAC MD9990 WCAP-17549-NP, Rev 2
Download: ML13248A348 (88)

Text

L-MT-1 3-091 ENCLOSURE 13 WESTINGHOUSE WCAP-17549-NP (NONPROPRIETARY), REVISION 2 MONTICELLO REPLACEMENT STEAM DRYER STRUCTURAL EVALUATION FOR HIGH-CYCLE ACOUSTIC LOADS USING ACE 87 pages follow Westinghouse Non-Proprietary Class 3 WCAP-17549-NP Revision 2 Monticello Replacement Steam Dryer Structural Evaluation for High-Cycle Acoustic Loads Using ACE IWestinghouse August 2013 WESTINGHOUSE NON-PROPRIETARY CLASS 3 ii WCAP-17549-NP Revision 2 Monticello Replacement Steam Dryer Structural Evaluation for High-Cycle Acoustic Loads Using ACE Yan Han Gary Plonczak Charles Rajakumar Amir Salehzadeh David Suddaby Robert Theuret Leslie Wellstein Edited by: David Suddaby*Reviewed by Leslie Wellstein*

Acoustic and Structural Analysis August 2013 Approved: David Forsyth*, Manager Acoustic and Structural Analysis*Electronically approved records are authenticated in the electronic document management system.Westinghouse Electric Company LLC 1000 Westinghouse Drive Cranberry Township, PA 16066© 2013 Westinghouse Electric Company LLC All Rights Reserved iii Record of Revisions Rev Date Revision Description 0 May Acoustic load input developed with [ ] a.c 0 2012 (per WCAP- 17540-P Rev. 0)March Acoustic load input developed with [] ac 2013 (per WCAP-1 7716-P Rev. 0)See Acoustic load input developed with [ ]a,c EDMS (per WCAP-17716-P Rev. 1)WCAP- 17549-NP August 2013 Revision 2 iv TABLE OF CONTENTS I IN TRO D U CTIO N ........................................................................................................................

1-1 2 M ETH O D O LO G Y .......................................................................................................................

2-1 2.1 A CO U STIC LO A D A N A LY SIS .....................................................................................

2-1 2.1.1 O verview .............................................................................................................

2-1 2.1.2 D esign Requirem ents ..........................................................................................

2-1 2.1.3 D ryer G eom etry ..................................................................................................

2-2 2.2 1 p c ...........................................

2-2 3 FIN ITE ELEM EN T M O D EL D ESCRIPTIO N ............................................................................

3-1 3.1 STEA M D RY ER G EO M ETRY .......................................................................................

3-1 3.2 FINITE ELEMENT MODEL MESH AND CONNECTIVITY

......................................

3-2 3.2.1 M esh D ensity Study ............................................................................................

3-2 3.2.2 Shell-Solid Connections in the FEM ..................................................................

3-3 3.2.3 Vane Bank Representation

..................................................................................

3-3 3.2.4 Lifting Rod Representation

.................................................................................

3-4 3.2.5 Beam -Solid Connections in the FEM ...............................................................

3-4 3.2.6 D ryer Skirt Subm erged in W ater .........................................................................

3-4 4 M ATERIA L PRO PERTIES ..........................................................................................................

4-1 4.1 STRUCTURA L D A M PIN G ............................................................................................

4-1 5 M O DA L AN A LY SIS ....................................................................................................................

5-l 6 LO A D A PPLICATION

.................................................................................................................

6-1 7 STRU CTU RA L A N A LY SIS ........................................................................................................

7-1 7.1 H A RM ON IC A N A LY SIS ................................................................................................

7-1 7.1.1 ..................

[.................................................

7-1 7.1.2 O verview -Tim e-H istory Solution .....................................................................

7-1 7.1.3 Inverse Fourier Transform

..................................................................................

7-2 7.1.4 Frequency Scaling (Shifting)

..............................................................................

7-3 7.2 PO ST-PRO CESSIN G ......................................................................................................

7-4 7.2.1 Prim ary Stress Evaluation

...................................................................................

7-4 7.2.2 A lternating Stress ................................................................................................

7-4 7.3 CALCULATION AND EVALUATION OF WELD STRESSES ....................................

7-5 7.4 SU BM O D ELIN G TECHN IQ U ES ..................................................................................

7-8 7.5 [ ]ac ...................

7-9 8 A N A LY SIS RESU LTS .................................................................................................................

8-1 8.1 G LO BA L M O D EL ..........................................................................................................

8-1 8.2 SU BM O D ELIN G ............................................................................................................

8-1 WCAP- 17549-NP August 2013 Revision 2 V 8.2.1 [c .............

.......................

1........

-8.2.2 Subm odel M esh D ensity .....................................................................................

8-1 8.3 A SM E A lternating Stress Calculations

............................................................................

8-2 9

SUMMARY

OF RESULTS AND CONCLUSIONS

...................................................................

9-1 10 R E FE R E N C E S ...........................................................................................................................

10-1 APPENDIX A SKIRT SLOT SUBMODEL MESH DENSITY STUDY .............................

A-i WCAP- 17549-NP August 2013 Revision 2 vi LIST OF TABLES Table 2-1 Table 2-2-2 Table 4-1 Table 4-2 Table 8-1 Table 8-2 Table A-I Table A-2 Vane Passing Frequency

[ ]C ....................................

2-3 Summary of Maximum Vane Passing Frequency Stress at EPU .....................................

2-3 Sum m ary of M aterial Properties

......................................................................................

4-2 Summary of Vane Bank [ ]a.b,. .....................................

4-2 Summary of Results at EPU: Components

[]a,c ...................

8-3 Summary of Results at EPU: Components

[ ]a,c ..........................

8-4 Submodel Cut Boundary Stress Comparison

..................................................................

A-2 Submodel Cut Boundary Stress Comparison

..................................................................

A-2 WCAP- 17549-NP August 2013 Revision 2 vii LIST OF FIGURES Figure 1-1 Schem atic of M onticello Replacem ent Steam D ryer ..............................................................

1-2 Figure 2-1 G eom etry Plot: [ ]a3C ........................................................................................

2-4 Figure 2-2 G eom etry Plot: [ ]a. .............................................................................................

2-5 Figure 2-3 G eom etry Plot: [ ]a,c ............................................................................

2-6 Figure 2-4 G eom etry Plot: [ ]a,c ..................................................................................

2-7 Figure 2-5 G eom etry Plot: [ ]afc .........................................................................

2-8 Figure 2-6 G eom etry Plot: [ ]a ..............................................................

2-9 Figure 2-7 G eom etry Plot: [ ], .......................................................

2-10 Figure 3-1 M onticello Replacem ent Steam D ryer Finite Elem ent M odel ................................................

3-5 Figure 3-2 Low er [ ]a,c .......................................................................................................

3-6 Figure 3-3 Low er [ ...C ............................................................................................

3-7 Figure 3-4 Vane Bank Structural Com ponents ..........................................................................................

3-8 Figure 3-5 Vane Bank G eom etry ..............................................................................................................

3-9 Figure 3-6 D ryer H ood G eom etry ...........................................................................................................

3-10 Figure 3-7 Skirt G eom etry ......................................................................................................................

3-11 Figure 3-8 [ ]ax ...............................................

3-12 Figure 3-9 [ ja] c .........................................................................

3-13 Figure 3-10 [], ................................................................

3-14 Figure 3-11 Lifting Rod G eom etry .........................................................................................................

3-15 Figure 3-12 [ ]a3 ............................................................................................

3-16 Figure 3-13 [ ]a.&. ...............................................................................................

3-17 Figure 3-14 [ ]a.c. .............................

3-18 Figure 3-15 [ ]a'c ...............................................

3-19 Figure 3-16 [ ]a'c .........................................................

3-20 Figure 3-17 Structural Com ponents of Vane Bank .................................................................................

3-21 Figure 3-18 Structural and N on-Structural Com ponents of Vane Bank ..................................................

3-22 Figure 3-19 Vane Bank M ass Blocks ......................................................................................................

3-23 Figure 3-20 [ ]jac ..........................................

3-24 Figure 5-1 M odal A nalysis: [ ]a.c. .........................................................................................

5-2 Figure 5-2 M odal A nalysis: [ ],. c ...........................................................................

5-3 Figure 5-3 M odal A nalysis: [ ]., ........................................................................

5-4 WCAP-17549-NP August 2013 Revision 2 viii Figure 5-4 Figure 6-1 Figure 6-2 Figure 6-3 Figure 6-4 Figure 8-1 Figure 8-2 Figure 8-3 Figure 8-4 Figure 8-5 Figure 8-6 Figure A-I Figure A-2 Figure A-3 Figure A-4 Figure A-5 M odal Analysis:

[]a,c .............................................................................

5-5[ ]a c .......................................................................

6 -3[ ] c.p ...............................................................................

6 -4[ ]a ..............................

6-5[]a' .............

6-6[ ]a~c ..........................................................................................

8 -5[] , ...................................................................................

8 -6[]"' ...................................................

8-7[] ,c .....................................................................

8 -8]a,c ..........................................................

8 -9[31C,...............

8-10 Submodel [],c ...................................................

A-3 Submodel M esh Densities

.....................................................................................................

A-4[ ]8' Submodel Results ......................................................................................

A-5[ ]plc Submodel Results ............................................................................................

A-6[ ]ax Submodel Results ................................................................................................

A-7 WCAP- 17549-NP August 2013 Revision 2 ix EXECUTIVE

SUMMARY

A high-cycle fatigue evaluation of the Westinghouse replacement steam dryer for the Monticello plant has been completed with loads generated using the Acoustic Circuit Enhanced (ACE) Revision 2.0 []a c Acoustic loads and stresses for extended power uprate (EPU) conditions have been evaluated for high-cycle fatigue and have been determined to meet the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code Section III, Subsection NG criteria.]a,,. These results account for all the biases and uncertainties in the acoustic loads models and finite element analyses.

To account for uncertainties in the modal frequency predictions of the finite element model (FEM), the stresses are also computed for loads that are shifted in the frequency domain by [ ]"'. These results also include a conservative estimate of the high cycle fatigue stress caused by vane passing frequency (VPF) of the recirculation pumps.WCAP- 17549-NP August 2013 WCAP- I17549-NP August 2013 Revision 2 x LIST OF ABBREVIATIONS Abbreviation ACE ASME B&PV BWR CLTP EPU FEM FSRF IFT MPC MSL MWt SCF I VB VPF 2-D 3-D Description acoustic circuit enhanced American Society of Mechanical Engineers boiler and pressure vessel boiling water reactor current licensed thermal power extended power uprate finite element model fatigue strength reduction factor inverse Fourier transform multi-point constraint main steam line megawatts thermal stress concentration factor]a,c vane bank vane passing frequency two-dimensional three-dimensional Trademark Note: ANSYS, ANSYS Workbench, CFX, AUTODYN, and any and all ANSYS, Inc. product and service names are registered trademarks or trademarks of ANSYS, Inc. or its subsidiaries located in the United States or other countries.

WCAP- 1 7549-NP August 2013 WCAP-17549-NP August 2013 Revision 2 1-1 1 INTRODUCTION In 2002, after increasing power to 117% of the original licensed thermal power, the steam dryer in a boiling water reactor (BWR) had a significant reduction in its structural integrity.

After extensive evaluation by various industry experts, the root cause of the dryer degradation was determined to be acoustic fluctuating pressure loads on the dryer, resulting from resonances produced by steam flow in the main steam lines (MSLs) across safety and relief valve inlets. The degradation experienced in the steam dryer of a BWR led to changes to Regulatory Guide 1.20, requiring plants to evaluate their steam dryer before any planned increase in power level.The Monticello power plant has contracted Westinghouse for a replacement steam dryer, and is also planning a power uprate. In conjunction with the component replacement by Monticello and the planned power uprate, an analysis has been performed to qualify the replacement steam dryer, shown in Figure I-1, for acoustic pressure loads and vibratory loads caused by vane passing frequency of the recirculation pumps. The process used to perform the analysis involves []" Acoustic loads applicable to EPU conditions are evaluated.

A dynamic analysis is performed using []a,c WCAP- 17549-NP August 2013 Revision 2 1-2 ac Figure 1-1 Schematic of Monticello Replacement Steam Dryer WCAP- I 7549-NP August 2013 Revision 2 2-1 2 METHODOLOGY

2.1 ACOUSTIC

LOAD ANALYSIS 2.1.1 Overview An analysis has been performed to assess the structural integrity of the replacement dryer for the Monticello plant subject to acoustic loads. []a,c 2.1.2 Design Requirements 2.1.2.1 [a,c The replacement dryer is analyzed according to the 2004 Edition of the ASME B&PV Code, Subsection NG (Reference 1). This report documents the suitability of the replacement dryer for high-cycle fatigue loads resulting from acoustic loads and vane passing frequency loads due to the recirculation pumps. The governing criterion for the analysis is in terms of the allowable component fatigue usage.The objective of this analysis is to show that the maximum alternating stress intensity anywhere in the dryer is less than the material endurance strength at 10"l cycles. The applicable fatigue curve for stainless steel (the dryer is manufactured from SS316L), is shown in Figure 1-9.2.2 in Appendix I of the ASME Code.[pac 2.1.2.2 Young's Modulus Correction Before comparing the maximum alternating stress intensity to the ASME Code endurance strength, it is necessary to account for the Young's modulus correction.

The analysis uses a Young's modulus of 25.425 x 106 psi, compared to the value to construct the fatigue curves of 28.3 x 106 psi. The ratio that is applied to the calculated alternating stress intensities is 1.113 (28.3 / 25.425).WCAP-17549-NP August 2013 Revision 2 2-2 2.1.2.3 1 I aC[2.1.3 Dryer Geometry Plots showing various aspects of the dryer configuration are provided in Figures 2-1 through 2-7.2.2 [ a,c I WCAP- 17549-NP August 2013 Revision 2 2-3 abc I Table 2-1 Vane Passing Frequency

[ ]C Table 2-2-2 Summary of Maximum Vane Passing Frequency Stress at EPU ab,c WCAP- 17549-NP August 2013 Revision 2 2-4 a,c Figure 2-1 Geometry Plot: I Ia,c WCAP- 1 7549-NP August 2013 Revision 2 2-5 a,c Figure 2-2 Geometry Plot:[I axc WCAP-17549-NP August 2013 Revision 2 2-6 a,c Figure 2-3 Geometry Plot: I I 8,C WCAP- I 7549-NP August 2013 Revision 2 2-7 a,c 1 Figure 2-4 Geometry Plot: [WCAP-1 7549-NP August 2013 WCAP-17549-NP August 2013 Revision 2 2-8 a,c Figure 2-5 Geometry Plot: [I a, WCAP-1 7549-NP August 2013 Revision 2 2-9 ac Figure 2-6 Geometry Plot: [121C WCAP-1 7549-NP August 2013 Revision 2 2-10 a,c Figure 2-7 Geometry Plot: I I a,c WCAP-17549-NP August 2013 Revision 2 3-1 3 FINITE ELEMENT MODEL DESCRIPTION

3.1 STEAM

DRYER GEOMETRY The Monticello replacement steam dryer FEM, generated using the ANSYS computer code', is shown in Figure 3-1. The model consists primarily of [P.C.I]a,c.The dryer structure includes []a..The [I'll The analysis qualification of the Monticello replacement steam dryer was performed using the]a.c WCAP-17549-NP August 2013 Revision 2 3-2 Figure 3-11 shows the []a,c 3.2 FINITE ELEMENT MODEL MESH AND CONNECTIVITY The dryer plates are all modeled]a.c The vane bank []a,c.I]a" are shown in Figure 3-16.3.2.1 Mesh Density Study A mesh density study was performed using]31c WCAP-1 7549-NP August 2013 Revision 2 3-3 3.2.2 Shell-Solid Connections in the FEM A study was performed to investigate the load transfer between shells and solids using]a,c 3.2.3 Vane Bank Representation The vane bank modules are box-like structures with many internal hanging chevrons.]"c and are shown in more detail in Figure 3-17.The perforated plates []"' are shown in Figure 3-18.Also shown in Figure 3-18 are the []ac.The vane bank []a' are shown in Figure 3-14.WCAP- 17549-NP August 2013 Revision 2 3-4 3.2.4 Lifting Rod Representation The lifting rod is modeled are shown in Figure 3-16.3.2.5 Beam -Solid Connections in the FEM A study was performed to evaluate the moment transfer and adequacy of the []a,c 3.2.6 Dryer Skirt Submerged in Water The dryer skirt is partially submerged in water.Ia,c WCAP- 17549-NP August 2013 Revision 2 3-5 ac Figure 3-1 Monticello Replacement Steam Dryer Finite Element Model WCAP- I 7549-NP August 2013 WCAP- 17549-NP August 2013 Revision 2 3-6 a,c Figure 3-2 Lower I ac WCAP-17549-NP August 2013 Revision 2 3-7 a,c Figure 3-3 Lower I] 2,c WCAP-17549-NP August 2013 Revision 2 3-8 a,c Figure 3-4 Vane Bank Structural Components WCAP- 1 7549-NP August 2013 WCAP- 17549-NP August 2013 Revision 2 3-9 a,c Figure 3-5 Vane Bank Geometry WCAP-17549-NP August 2013 Revision 2 3-10 a,c Figure 3-6 Dryer Hood Geometry WCAP-17549-NP August 2013 Revision 2 3-11 a,c Figure 3-7 Skirt Geometry WCAP- 17549-NP August 2013 Revision 2 3-12 a,c Figure 3-8 [I a,c WCAP- 1 7549-NP August 2013 Revision 2 3-13 a,c Figure 3-9 []a, C WCAP-17549-NP August 2013 Revision 2 3-14 ac Figure 3-10 [I a,c WCAP-17549-NP August 2013 Revision 2 3-15 a,c Figure 3-11 Lifting Rod Geometry WCAP-17549-NP August 2013 Revision 2 3-16 a,c Figure 3-12 [a, C WCAP-17549-NP August 2013 Revision 2 3-17 a,c Figure 3-13 1 la,c WCAP-17549-NP August 2013 Revision 2 3-18 a,c Figure 3-14 ]a,1C WCAP- 17549-NP August 2013 Revision 2 3-19 a,c Figure 3-15 [I a,c WCAP- 17549-NP August 2013 Revision 2 3-20 a,c Figure 3-16 [I a,c WCAP- 17549-NP August 2013 Revision 2 3-21 a,c Figure 3-17 Structural Components of Vane Bank WCAP- I 7549-NP August 2013 Revision 2 3-22 a,c 1 Figure 3-18 Structural and Non-Structural Components of Vane Bank WCAP- 1 7549-NP August 2013 Revision 2 3-23 a,c Figure 3-19 Vane Bank Mass Blocks WCAP- 17549-NP August 2013 Revision 2 3-24 ac Figure 3-20 [12,C WCAP- 17549-NP August 2013 Revision 2 4-1 4 MATERIAL PROPERTIES The material properties used in the structural analysis are summarized in Table 4-1. Material properties are taken from the ASME Code, Reference 2, for []a are summarized in Table 4-2.4.1 STRUCTURAL DAMPING Structural damping is defined as 1% of critical damping for all frequencies.

This damping is consistent with guidance given on page 10 of NRC RG-1.20 (Reference 3). Using the harmonic analysis approach, a consistent damping level is used across the frequency domain.WCAP-17549-NP August 2013 Revision 2 4-2 Table 4-1 Summary of Material Properties a,b,c Table 4-2 Summary of Vane Bank r ja~bxc ab,c WCAP- 17549-NP August 2013 Revision 2 5-1 5 MODAL ANALYSIS As a precursor to performing the transient analysis, a modal analysis of the dryer was performed.

The modal analysis was performed for modes between 0 Hz and 140 Hz. Some modes for the hood and skirt are shown in Figure 5-1 through Figure 5-4. The fundamental modes for the [],*, respectively.

The acoustic fatigue evaluation includes loads in the range from 0 Hz to 250 Hz. This modal analysis is not intended to be complete but only a check of the finite element model.WCAP-17549-NP August 2013 Revision 2 5-2 ac Figure 5-1 Modal Analysis:

[Sa,c WCAP- 17549-NP August 2013 Revision 2 5-3 a,c Figure 5-2 Modal Analysis:

I I.o WCAP-17549-NP August 2013 Revision 2 5-4 ac Figure 5-3 Modal Analysis:

I Ia,c WCAP- 17549-NP August 2013 Revision 2 5-5 a~c 7 Figure 5-4 Modal Analysis:

[I a,c WCAP- 17549-NP August 2013 Revision 2 6-1 6 LOAD APPLICATION The frequency-dependent acoustic loads were developed using a three-dimensional (3-D) acoustic model representation of the dryer assembly.

The acoustic pressure (P) loads on the steam dryer structure were calculated by [WCAP-17549-NP August 2013 Revision 2 6-2]a,c WCAP-17549-NP August 2013 Revision 2 6-3 a,b,c Figure 6-1 [la,c WCAP- 17549-NP August 2013 Revision 2 6-4 a,x Figure 6-2 [I a,C WCAP-17549-NP August 2013 Revision 2 6-5 a,c Figure 6-3 [Ia,c WCAP- I 7549-NP August 2013 Revision 2 6-6 a,c 7 Figure 6-4 f I a,C WCAP-17549-NP August 2013 Revision 2 7-1 7 STRUCTURAL ANALYSIS 7.1 HARMONIC ANALYSIS 7.1.1 1 ] 2C Harmonic solutions are obtained using the ANSYS Monticello replacement FEM for the following sets of conditions:

Model Support (Boundary)

Conditions The model is supported

[]a.c Operating Conditions EPU operating conditions are evaluated.

Frequency Shifts[]a,c.7.1.2 Overview -Time-History Solution The harmonic analysis begins with the [],c. As discussed above, separate solutions are obtained for [WCAP-17549-NP August 2013 Revision 2 7-2 a,c.I]a,c.I]a,c.It was found to be inefficient to process the results]ac" I I]a.c.[]a.c.7.1.3 Inverse Fourier Transform I WCAP- 17549-NP August 2013 Revision 2 7-3 pac 7.1.4 Frequency Scaling (Shifting)

As a result of approximations of the structural interactions used in developing the FEM, small errors can result in the prediction of the component natural frequencies.

Varying degrees of mesh discretization can also introduce small errors in the FEM results. To account for these effects, frequency scaling is applied to the applied load history.If frequency scaling is applied,]a,c WCAP- 17549-NP August 2013 Revision 2 7-4 7.2 POST-PROCESSING

7.2.1 Primary

Stress Evaluation Once the time-history has been calculated

[ an evaluation is performed to calculate the maximum alternating stress intensity.

The stress intensities for the]a,c.For a two-dimensional stress field, the principal stresses are calculated as follows (the X-Y plane is used as an example. The same algorithms are also applicable to other planes.)G5x +GOy --___y a + T+x_ Y )C7,2 2 -- 2 +)G3 = 0.0 Stress Intensity

= Maximum ac 2 -a 3 1 ao 3 -oI For a general 3-D state of stress, the resulting principal stresses correspond to the roots of the following cubic equation as: ("3 -_ a 2 o2 + ai -ao = 0 where, a 2 = a. + ay + ayz a, = ayýa + ay T + az~a -a\,) -a)yz2 -2a ao = aya(3y -z + 2a7XYCTyzCT

-Ocyz 2 -aayzx 2 -cyzyxy2 7.2.2 Alternating Stress The calculation of the alternating stress intensity, following the ASME B&PV Code,Section III, Division I -NG process, is performed as follows: 1. Apply the stress concentration factors (geometric or FSRF), as applicable, to the component stresses.2. Calculate the range of stress for each component of stress for two time points.3. Calculate the stress intensity of the component ranges.WCAP-17549-NP August 2013 Revision 2 7-5]a,c.7.3 CALCULATION AND EVALUATION OF WELD STRESSES Due to the nature of the dynamic analysis, detailed modeling of the welds is not practical in the global dryer FEM. Calculation of weld stresses requires a different approach.

For the Monticello replacement steam dryer, []a,c.As discussed above, detailed weld stresses are not directly available from the finite element analysis.[]a,c.WCAP-17549-NP August 2013 Revision 2 7-6[I a,c WCAP-1 7549-NP August 2013 Revision 2 7-7[I a,c WCAP- 17549-NP August 2013 Revision 2 7-8 ac 7.4 SUBMODELING TECHNIQUES Due to the nature of the acoustic analysis and the large number of unit solutions that are required, it is not practical to use a fine mesh for the acoustic structural analysis.

Rather a mesh density that can accurately predict the dynamic characteristics of the structure is used, but may require some additional analysis for localized regions of high stress. For areas where additional analysis is necessary using a more refined element mesh, a technique known as submodeling is used. The submodeling method [ac.WCAP-17549-NP August 2013 Revision 2 7-9 7.5 ] 1]a,c.WCAP- 17549-NP August 2013 Revision 2 8-1 8 ANALYSIS RESULTS 8.1 GLOBAL MODEL As discussed previously, jaG,.A summary []a,c 8.2 SUBMODELING Based on the results for the global model, jax.8.2.1 [I a,c[1a3c 8.2.2 Submodel Mesh Density To demonstrate that the [ ]a,c submodel results are appropriate,]ac The comparison and results are documented in Appendix A of this report.WCAP-17549-NP August 2013 Revision 2 8-2 8.3 ASME ALTERNATING STRESS CALCULATIONS Section 7.2.2 discusses the jac WCAP- 17549-NP August 2013 Revision 2 8-3 Table 8-1 Summary of Results at EPU: Components

]a,b,c WCAP-17549-NP August 2013 Revision 2 8-4 Table 8-2 Summary of Results at EPU: Components

[ Ia.c a,b,c Table 8-3ASME Alternating Stress Calculation Summary a,b,c+i i.4--I-WCAP- I 7549-NP August 2013 Revision 2 8-5 a,c Figure 8-1 [Sa,c WCAP- 17549-NP August 2013 Revision 2 8-6 ac Figure 8-2 [] a.c WCAP-17549-NP August 2013 Revision 2 8-7 a,b,c Figure 8-3 1 ]WCAP- 17549-NP August 2013 Revision 2 8-8 a,b,c Figure 8-4 [I a,c WCAP- I 7549-NP August 2013 Revision 2 8-9 I a,b,c Figure 8-5 [I a,c WCAP-17549-NP August 2013 Revision 2 8-10 a,b,c Figure 8-6 1 Saxc WCAP- 17549-NP August 2013 Revision 2 9-1 9

SUMMARY

OF RESULTS AND CONCLUSIONS I I I]a,c.]a,c.WCAP- 1 7549-NP August 2013 WCAP- 17549-NP August 2013 Revision 2 10-1 10 REFERENCES

1. ASME Boiler and Pressure Vessel Code, 2004 Edition,Section III, Division 1.2. ASME Boiler and Pressure Vessel Code, 2004 Edition,Section II, Part D.3. U.S. Nuclear Regulatory Commission, Regulatory Guide 1.20, Rev. 3, "Comprehensive Vibration Assessment Program for Reactor Internals During Preoperational and Initial Startup Testing," March 2007.4. [pac 5. [axc 6. []axc 7. BWR Vessel and Internals Project, Guidance for Demonstration of Steam Dryer Integrity for Power Uprate. Electric Power Research Institute, Palo Alto, CA: May 2010. BWR-182-A.

WCAP- 17549-NP August 2013 Revision 2 A-1 APPENDIX A SKIRT SLOT SUBMODEL MESH DENSITY STUDY To illustrate that the submodel results used are appropriate,]a,c WCAP-17549-NP August 2013 Revision 2 A-2 Table A-i Submodel Cut Boundary Stress Comparison Table A-2 Submodel Cut Boundary Stress Comparison a,b,c a,b,c WCAP-1 7549-NP August 2013 WCAP- 17549-NP August 2013 Revision'-'

A-3 a,b,c Figure A-1 Submodel [] a.c WCAP- 1 7549-NP August 2013 Revision 2 A-4 a,b,c Figure A-2 Submodel Mesh Densities WCAP-1 7549-NP August 2013 Revision 2 A-5 a,b,c Figure A-3 [jaIc Submodel Results WCAP-1 7549-NP August 2013 WCAP- 17549-NP August 2013 Revision 2 A-6 a,b,c Figure A-4 ILC Submodel Results WCAP- 17549-NP August 2013 Revision 2 A-7-- a,b,c Figure A-5 []C Submodel Results WCAP-17549-NP August 2013 Revision 2