ML080100282

Presentation to NRC by Vermont Yankee Regarding Environmental Fatigue Analyses for License Renewal

ML080100282
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	01/08/2008
From:	Thayer J Entergy Operations
To:	Office of Nuclear Reactor Regulation
References
TAC MD2297
Download: ML080100282 (55)

Text

iteinteEntergy, Nuclear Presentation to NRC Staff Regarding Reactor Pressure Vessel Nozzle Environmental Fatigue Analyses for License Renewal Vermont Yankee-Nuclear Power Station- (VY-NPS)

~Enteigy NRC Public Meeting, 1/8/20081 1

1 tergy Instroduct'ilon, Jay Thayer Vice: Pres-idenat Entergy NRC Public Meeting, 1/8/20082 2

uwl~tergyAgna d-

-a

• Overview

• Technical Presentation

• Open Discussion 3* Summary/Follow-up Actions

• Closing Remarks

~Enteigy NRC Public Meeting, 1/8/20083 3

nierg T echnical,, Pres,,nr t'a ti,-o)nj il Grand Gulf

--Umýý

" Open Technical Questions

• Nomenclature

" Industry Experience

" VYNPS Fatigue Analysis Methodollogy

" Conservatisms in VYNPS Ana lysis Approach

" Basis for Acceptabil1ity of VYNPS Approach

" Confirmatory Analyses NRC Public Meeting, 1/8/20084 4

ditegj I -."'I..If I

I I

Opeinii T chinicalF" Que-,-st-fijo~ns I

I TEntergy NRC Public Meeting, 1/8/20085 5

iteigy Op e n Tie-,.c--hnicalI Qu e stilns

!d~

RAI 4. 3.3-2 Question's m Use of axisymmetric. model for vessel I

nozzles.

I m Use of component stresses in lieu of principal stresses.

I m Use of Green's Functions for thermal transients.

I Enterý NRC Public Meeting, 1/8/20086 6

1 ergy I

N~onieneia tu1-1r-e EnteW NRC Public Meeting, 1/8/20087 7

iteigy jNI om,,,/encIIa-Terminology requiring clarification 0 "21D" vs. 3D mNozzle corner contour effects E "1 D virtual stress" m Use of a single stress difference vs. using 6 stress components m Nozzle corner, blend radius & inner radius are interchangeable terms.

NRC Public Meeting, 1/8/20088 8

teigy Nv,"o-)fmiie rnon cr;I turej I i I

Z L)

W 0n Z

I I

I Z

cc I

Entfergy VYNPS Feedwater Nozzle NRC Public Meeting, 1/8/20089 9

teigy VYNPS Fatigue Analysis U

Mettho dorlogy NRC Public Meeting, 1/8/2008

Enter, 10

Ite i

I rgyY P Fatigue Analysilsr MetVoYoNNgy)

SJ M,

1`

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odag

1.

An axisym metric nozzle finite element model (FEM) is develop-ed from plant-specific drawings and material specifications.

2. Heat transfer coefficients and boundary conditions are established for the FEM based on the RPV Certified Design Specification and Stress Report.

3. The thermal stress response (i.e., Green's Function) is developed for a step change in temperature. A scalable pressure stress is separately obtained by applying a unit pressure load to the FEM.

I I

I I

Entery NRC Public Meeting, 1/8/2008 111

ntegyV/Y NIPS, Fatiue-A nralysis1

4. Thermal transients are based on appropriate Design Specification and BWR-4 thermal cycle definitions.

)<ANO, 1~

5. Thermal stress histories are obtained (using Green's Function integration) for each thermal transient. The Green's Function results are 7

reviewed for appropriateness.

IRiver Bend

-73 6. The associated pressure for each thermal stress point is determined based on linearly scaling the

-- 7 unit pressure stress response based on the transient, pressure time history.

LfEnteWg NRC Public Meeting, 1/8/2008 112

te-igy V'ryN týij gr/ý N

7, ý !')

Pow S -Frr::

ure Analysi W

/ -is N

..a t~~.ir 7.

Stresses due to attached piping loads are conservatively calculated and are scaled based-on RPV temperature for each transient.

I 8.

NB-3200 fatigue analysis is performed for the collected thermal transients stress histories, conservatively combining the thermal, pressure (with a scaling factor to 'account for'nozzle, contour effects), and attached piping stresses, and using conservative cycle projections to determine the 60-year CUF.

I

2 The VYNPS methodology is the same as the approach used for most CLB BWR RPV nozzle fatigue analyses..

NRC Public Meeting, 1/8/2008 113

,t~VYPSFaigjue Analsis Gra?~d Gulf' 9.

I Maximum fatigue life correction factors (F en multipliers) are calculated for water chemistry conditions (including power uprate effects) expected to occur over the 60-year operating period.

I

10. Environmental fatigue effects are calculated by multiplying the CUF for 60 years by the Fen, I

I I

~Entiegy NRC Public Meeting, 1/8/2008 114

1 tergy F

F V/YNPSAnalysi A p_-p r oach I

F

ý:EnteriW NRC Public Meeting, 1/8/2008 115

• Constant (bound ing) material properties are used.

• The FEM mesh is much finer than that used in the CLB stress analyses for VYN PS, which results in h Iigher peak stresses. [1,2,4,11,14]

• Thermal stresses are calculated using

-'41 '61conservative heat transfer coefficients based on bounding flow rates. [4,11,14]

Attached piping stresses are always combined with thermal stresses with like signs., such that C.'yc"ýthey always maximize alternating stress ranges.

NRC Public Meeting, 1/8/2008 116

ditegy

.Conservlatlis,.,m,,s Mn VYNPS Anal~i k E~

FO%

ht I

I I. - -

I, - I,,

11

• Bounding values for pressure' and temperature (at power uprate conditions) are assumed for the entire 6,O-year period of plant operation. [9,- 13, 161 I

• The entire stress time history for each transient is generated, compared to selected transient points generated in the CLB stress analysis. This ensures that maximum peak stresses are used.

I

• Ke is calculated consistent with current ASMVE Code methodology, which ensures alternating stresses are maximizend. Ke was not required for the VYNPS CLB vessel fatigue analys-is.

[1, 2, 5,9,10,13,16]

[ygI NRC Public Meeting, 1/8/2008 117

tergy Co-)n js e ýrva-,tji s-,ms min VYN,,P-jS)

A na is AW noaI I

ran Glf I

The number of transient cycles for 60 years used in the analysis is conservative relative to the number of transients experienced to-date and expected through 60 years of operation (to be monitored). 1191 I

• Design basis transient, severity definitions were used.

I 0

Bounding F en multipliers were values for temperature, strain content that were selected to multiplier. [10]

calculated using rate and sulfur maximize the F en I

11 Entergy NRC Public Meeting, 1/8/2008 118

i tergy io 1-11.1-1 i 91 tr e

rt du jrv El' i, e-Fj '--,,

--,; r-in -m I ýEntergy NRC Public Meeting, 1/8/2008 119

itergy Ind'st ry Exerience K

m VYNPS considered methodology I

previous license renewal applican used by its (used by:

m VYNPS selected the methodolog)

I m Dresden/Quad Cities m Nine Mile Point Unit 1 I

m Oyster Creek I

m Ginna m Point Beach m Farley I Palisades I

~EnteqVy m Millstone 2/3 NRC Public Meeting, 1/8/2008 220

Enteigy NRC Public Meeting, 1/8/2008 221

tergy Basirs.frAcptblt of It ulf

• The nozzle FEM techniques and analysis methods used to establish stress histories are consistent with the current design and licensing bases (CLB) for V/YNPS.

I

• The use of Green's Functions for calculating thermal transient stresses is well established throughout the industry (since 1986). [6]

0 The multiple conservatisms in the analysis methods.

I

• The comparisons performed between the VYNPS approach and the-classical ASMVE NB-3200 approach show that the VYNPS approach provides equal or higher alternating stresses and fatigue usage. [18, 20]

ýEnteW~

I NRC Public Meeting, 1/8/2008 222

teigy I

GadGulf UJs-e of AxsymnrcMoe I

~EnteWg I

NRC Public Meeting, 1/8/2008 223

I

~Generalul

• The CLB RPV nozzle fatigue analyses for VYNPS are based on the use of axisymmetric modelS. [1, 2]

This approach has been. an industry standard for many years and is the basi~s for most existing I-nozzle fatigue analyses in U.S. operating reactors.

• The approach VYNPS used for environmental Ifatigue calculations is consistent with the VYNPS

-Ltegy NRC Public Meeting, 1/8/2008 24

itergy U~se of Axis0 -,ymmetri

-~

.,2-,

1 4

Technical Considerations

• Nozzle contour effects have been accounted for in the VYNPS axisymmetric models.

"Thermal transient stresses were shown in BWRVIP-108 to be azimuthally uniform in the nozzle/RPV contour region for a variety of RPV nozzles using full 3D (non-axisymmetric) finite element models

• For example, refer to the next slide. [3]

• Therefore, no adjustment for nozzle contour effects is required for thermal stresses.

" Pressure stresses were accounted for by increasing the radius of the reactor vessel in the axisym'Metric model (to be consistent with the CLB analysis) and/or application of an additional multiplier to fully account for nozzle contour pressure stress effects in the nozzle/RPV contour region..

NRC Public Meeting, 1/8/2008 225

UJse o xsymti iteWg Mo iderl Technical Considerations (typical example of results from BWRVIP-1 08)

AN

'c0pz EA OPK 0JZ Core Spray Nozzle. Blend Radius. Inside Surface ZLE. THERMAL 35000O 30C-00 25000 220000 10000 5D200 NRC Public Meeting, 1/8/2008 02 Auirnutti (degreei 26

Use of A xis ymm erric iteWg Mdel,1 GrndLffITechnical Considerations - Pressure Stress

• Multipliers on vessel radius have traditionally been used for CLB analyses to account for nozzle contour effects.

I

• The multipliers applied to environmental fatigue calculations are consistent with the maximum values used historically in the VYNPS CLB. [2, 4, 51

.1 "a

• The VYNPS nozzle analyses appropriately considered nozzle contour effects on stress..

• The finite element model accounts for material and geometric discontinuities of the nozzle corner.

I I En~itelgy

• A multiplier of 2.0 was used to account for the spherical modeling effect.

NRC Public Meeting, 1/8/2008 227

d erg3(

R Use of Component St,,r-e--sse.s.-

NRC Public Meeting, 1/8/2008 228

~tegyUse of Component Stres-es General Case (3D stress) [21]

(--ad 6411f L_

.'r-It can be shown that the complete state of stress can be determined by knowledge of Y

stress vectors on any three perpendicular CTY planes.

• It is conventional to consider the three mutually dI::ý perpendicular planes as faces of a cube of PRE_

infinitesimal size, a stress element.

T ZY The state of stress can be conveniently written CFX as a matrix or a tensor:

dtz TCzy T

• nysxcmoetsaeidpnet

~T~60p C/X'X TXZ Z,~

I~S YEntY yZ NRC Public Meeting, 1/8/2008 229

Uý ulterg Ue of C, -mp-.onen Stre-,sses

• There exists an orthogonal set of axes 1, 2, 3 called principal axes with Gul respect to which the stress state elements are all zero except for those in the principal diagonal:

[Gl 01

-0 0 73 L~i In other words, there always exists a set of mutually perpendicular planes with zero shear stress.

• The stress intensity, SI is defined as:

SI =MAXIMUM (cyl -

2, G2 3 1 ~31)

• Thus, if a stress difference based on component stresses (i.e., cy -CTX) equals SI, then shear stresses are negligible.

EnteTgý NRC Public Meeting, 1/8/2008 330

iieigy Us-e of ComponetSrs s

• The NSSS vendor practice for BWR CLB nozzle analyses has traditional~ly been to use component (Sx, Sy, Sz) stresses, for two reasons:

• ASMVE Code Section 111, NB-3215(d) states, "nmn

-7 1pressure component calculations, the t,, and r directions may be so chosen that the shear stress components are zero and a,, G2, and Cy are identical to at, cy1,'and oyr-"

• Experience indicated that shear stresses were negligible.

I The VYNPS CLB analyses used component stresses, since shear stresses are negligible. [2,4,5]

I

Entergy NRC Public Meeting, 1/8/2008 331

-Technical Considerations

-Feedwater Nozzle

• The impact of using component stresses was evaluated for the nozzle corner and safe end locations for all three nozzles analyzed for VYNPS.[7, 17]

• The feedwater nozzle has the highest environmentally 77_

adjusted CUE (0.639 at the nozzle corner and 0.256 at the safe end).

• The thermal stress response to a 400OF step-change in temperature for the to nozzle locations evaluated is shown on the next 2 slides. [7, 17]

• For both feedwater nozzle locations, excellent agreement exists between SI and the maximum component stress difference for the Green's Function.

• Based on this close agreement, using SI would not change

-~

the calculated CUF.

EnteWg NRC Public Meeting, 1/8/2008 332

I t er1Y.

UJ/ s-e aof C o, mn p) on len t' S-ttr e s,- s-,es-I Feedwater Nozzle, Corner Stress Difference Comparison Total Stress Intensity 30000

... ~w

+

25000 20000 15000 Sz-s 0

100 200 300 400 500

'EnteriW Time (sec)

NRC Public Meeting, 1/8/2008 333

tergy U s e o)f C om,,-tp )o, n-,lent S tr e.ss e-s m

~AJ Si Feedwater Nozzle Safe End Stress Difference Cornparison Total Stress Intensity 7a0000 60000 50000 40000 30000 20000

'A U)

I)

- sz-sx I;

-Sz-SY I

-S1 A1 0

-10000 TEnteWg NRC Public Mee 0

ting, 1/8/2008 100 200 300 400 500 Time (sec) 34

U tergy Us,ýe i -,of Comrrponre.,nt Strfes se s

-7 Technical Considerations - Core Spray Nozzle

" The core spray nozzle has the next highest environmentally adjusted CUE (0. 167 for the nozzle corner and 0.059 for the safe end). [16]

The thermal stress response to a 400OF step change in temperature for the two nozzle locations evaluated is shown on the next 2 slides. [7, 17]

There is very close agreement between SI and the maximum component stress difference at the nozzle corner.

• Based on this close agreement for the nozzle corner, using SI would not change the calculated CUF.

The safe end also has very good agreement at the peak value for the Green's Function. However, there was a difference (up to 50%) at decay stress values.

.0 Due to the difference in stresses for the safe end, a confirmatory evaluation was performed using SI. This resulted in a calculated increase in environmentally adjusted CUE of 0.003

" The total environmentally adjusted CUE increased from 0.059 to 0.062, or 5%. [-9

" This increase is small, is within the accuracy of the analysis, and is enveloped by conservatisms in the analysis.

a This small difference is a result of the Green's Function process, where the key comparison is the peak stress value.

" A significant margin of 0.833 exists with respect to the ASMVE Code limit of 1.0.

NRC Public Meeting, 1/8/2008 335

i teigy Use of Comonent, Stresses Core Spray Nozzle Corner Stress Difference Cornparison Total Stress Intensity 30000 25000 20000 15000 10000 5000 U) 0 U)

-5000

-10000

-15000

-20000

-25000

-30000 SNRC Public Meeting, 1/8/2008 100 200 300 400 Time (see) 500 36

iteigy Uiis-e o 0f,Ca'0 i"m-f(

p'-

ojne l..,nt, S tr-e s-ý sje--,s r

Core Spray Nozzle Safe End Stress Difference.

Cornparison Total Stress Intensity I

I I.

i-80000 70000 60000 50000 40000 30000 20000 10000 0

-10000

-20000

-30000

-40000

-50000

-60000

-70000

-80000 I

I I

Entergy Time (sec)

NRC Public Meeting, 1/8/2008 337

riergY Use of Compo_,nrent Strsses Technical Considerations

-Recirculation Outlet Nozzle

" The recirculation outlet nozzle has a environmentally adjusted CUE of 0.084 for the nozzle corner and 0.018 for the safe end. [13]

" The thermal stress response to a 400OF step change in temperature for the two nozzle locations evaluated is shown on the 2 follow-on slides. [7, 17]

" For the safe end location, there was excellent agreement between SI and the maximum component stress difference for the Green's Function.

• Based on this close agreement for the safe end, using SI would not change the calculated CUF.

I EnteW~

NRC Public Meeting, 1/8/2008 338

-Recirculation Outlet Nozzle Safe End Stress Difference Comparison 120000 10000 80000 6000 f

i- -

- SZ-Sx 20000___________________

-4000

-100000-

-1 20000

~-~Eterg

-14000Time (sec)

NRC Public Meeting, 1/8/2008 339

itergY. U~se of Co-mfp-oinient Stresses Technical Considerations

- Recirculation Outlet Nozzle

• For the nozzle corner loc 'ation, there was a difference of 10% between the peak values of SI and the maximum component stress difference for the Green's Function.

The difference between SI and the maximum component stress difference has a negligible effect because:

• The most significant thermal transient (Improper Start causing reverse flow) was modeled directly in the FEM due to its unique characteristics.

• In. the nozzle corner, the thermal stresses are small compared to the pressure stresses. [13]

• Due to the difference in stresses for the nozzle corner, a confirmatory evaluation was performed using SI. This resulted in a calculated increase in environmentally adjusted CUF of 0.003.

• The total environmentally adjusted CUF increased from.0.084 to 0.087, or 3.5%. [7]

• This increase is small, is within the accuracy of the analysis, and is enveloped by conservatisms in the analysis.

• A significant margin of 0.913 exists to the ASME Code limit of 1.0.

~EnteiTy NRC Public Meeting, 1/8/2008 440

tergY. Use-of Cmoent Streses I -I 7-Recircul Differeni 50000 30000 I

20000 30000

-10000

-20000-

-30000

-50000

-60000

-70000 NRC Public Meeting, 1/8/2008 ation Outlet Nozzle Corner Stress r~e Comparison Total Stress Intensity

'Entei 41

h ter~y I

I A -.

If I

I

Use, of Green $1ýs F~u-n~ct'io)n-, A-pproach I

I

~Eter~y I NRC Public Meeting, 1/8/2008 442

itergy Ue of Green's, Function, Ap pwr o-a-,,c;h HiI

• The use of integration functions, such as Green's Functions, are a well-established mathematical technique. [6]

m This approach is used to establish the correlation, or stress response, to a unit step change thermal transient.

m From the stress response to the unit step transient, a stress history can be easily integrated for any thermal transient.

• The method is accurate and reliable, and has proven mathematics behind it.

0 "Duhamel's Formulas" in most college engineering text books.

m Similar to integrating' the area under a curve, the only limitation is the size of the integration time step.

m The VYNPS Green's Functions utilize time steps as small as 0.01 second.

~EnterWg NRC Public Meeting, 1/8/2008 443

UsA

--e of Green's Function iteWg Approach I,

Green's Functions Grand-Gu If OL 450 400 350 300 250 200 Q, -

C,)

Time (sec) 92825r0 i

Note: A typical set of two Green's Functions is shown, each for a different set of heat transfer coefficients (representing different flow rate conditions).

Enterg NRC Public Meeting, 1/8/2008 444

Use. of Green's Function terg A /,A1ppro.ac-hF Green's Function Integration Process I

• 1 0

a I

I I

I 0o0 zoo Wo Mo I= Im 0 1400 1500 I=0 2000 M0 4W NO0 800 1000 1200 1IM IM010 I

2000 ft

=

• To compute the thermnal stress response for an arbitrary transient, the local fluid temperature is deconstructed into a series of step-loadings.

• By using the Green's Function, the response to each step can be quickly determined.

• By the principle of superposition, these can be added (algebraically) to determine the response to the original load history.

The result is demonstrated in the figure on the right.

The input transient temperature history contains five step-changes of varying size, as shown in the figure on the left.

These five step changes produce the five successive stress responses in the figure on the right. By adding all five response curves, the real-time stress response for the input thermal transient is computed.

• The Green's Function methodology produces identical results compared to running the input transient through the finite element model.

• The advantage of using Green's Functions is that many individual transients can be run with a significant reduction of effort compared to running all transients through the finite element model.

I

_`EnteWg NRC Public Meeting, 1/8/2008 445

i tergy rwul Gulf I,

ii Addtioal-onfr tory Rive

/o r

kd-7Entclgy NRC Public Meeting, 1/8/2008 46

nte_)n Cofr atoiry A nalyi Le;W'GadifiA benchmarking calculation will be performed of the limiting component (feedwater nozzle) as further confirmation of the VYNPS fatigue analysis i approach.

• The feedwater nozzle was chosen because:

• It has the largest number and the most severe Ruerlkndtransients.

• It has the largest fatigue usage.

• Results will be bounding for the core spray and 71-recirculation outlet nozzles.

• The analysis will be performed using the existing axisymmetric model.

NRC Public Meeting, 1/8/2008 7

W ntergy.

Con fim oyA ayi Grad ul

• All defined-transients will be eval'uated using the finite element model.

[

• -d All six stress components will be used to compute fatigue usage via ASMVE Section'1II NB-3200 methods.

• The CUF results will be compared to CUF results from the previous environmental fatigue calculations.

I EnleWg NRC Public Meeting, 1/8/2008 448

d ergy I

Op en DisC-ussion EnfeWg NRC Public Meeting, 1/8/2008 449

otergy I

I 01 9;

olait

,.5, ck 1/0 vs,-,' to)i nu I

I I

I "EnterVy NRC Public Meeting, 1/8/2008 550

E in tegtovlson

• VYNPS nozzle fatigue analyses were performed using modeling techniques (axisymmetric) and methodologies that are consistent with the CLB.

• The methods used in the. VYNPS nozzl e fatigue analyses

INO are consistent with classical ASMVE Code Section III NB-3200 methodology.

• Conservatisms exist in the analysis approach that bound any uncertainties, which are small when compared to the analysis results.

Bounding design basis transient definitions

• Bounding 60-year cycle counts

-*Bounding heat transfer coefficients

• Significant margin (0.36) remains to the ASME Code allowable value of 1.0 (maximum CUF is 0.64).

I

~EnteW NRC Public Meeting, 1/8/2008 551

d ergy G' "-I 60f,

)References NRC Public Meeting, 1/8/2008 552

ztergy Reoe 0e

-:A e

- r

,l e-.,

I1.

Chicago Bridge & Iron Company, Reactor Vessel Stress Report,

-1GW6ý-YnkeReactor, cnrt9-6201, October 1969.

2.

Teledyne Engineering Services Technical Report TR-6400-1, Fatigue Analysis Summary of Vermont Yankee Reactor Vessel,

1NO VYC 378, October 1985.

S3.

EPRI BWRVIP-1.08: BWR Vessel and Internals Project, "Technical Basis for the Reduction of Inspection Requirements for the Boiling Water Reactor Nozzle-to-Vessel Shell Welds and Nozzle Blend Radii, Report 1003557, October 2002.

14.

Calculation VY-1OQ-301, Rev'. 0, "Feedwater Nozzle Finite Element Model and Heat Transfer Coefficients", March 2004.

5.

Calculation VY-1OQ-303, Rev. 0, "Feedwater Nozzle Stress and Fatigue Analysis", March 2.004.

6.

Kuo, Tang & Riccardella ASME PVP Paper, "An On-Line Fatigue Monitoring System for Power Plants", presented at the 1986 Pressure Vessels and Piping Conference and Exhibition, Chicago, I

~ IL.

NRC Public Meeting, 1/8/2008 553

itergy R-eferences-.

772

7.

Letter, Entergy to USNRC, "Vermont Yankee Nuclear Power Station, License No. DPR-28, License Renewal Application, Amendment 33, BVY 07-082, dated December 11, 2007.

8.

Calculation VY-1 6Q-301, Rev. 0, "Feedwater Nozzle Stress History Development for Green's Functions",3 July 2007.

9.

Calculation VY-16Q-302, Rev. 0, "Fatigue Analysis of Feedwater Nozzle" July 2007.

10.

Calculation VY-16Q-303, Rev. 0, "Environmental Fatigue Evaluation of Reactor Recirculation Inlet Nozzle and Vessel Shell/Bottom Head"19, July 2007.

11.

Calculation VY-1 6Q-304, Rev. 0, "Recirculation Outlet Nozzle Finite Element Model"11, July 2007.

12.

Calculation VY-16Q-305, Rev. 0, "Recirculation Outlet Stress History Development for Nozzle Green Functions"11, July 2007.

13.

Calculation VY-16Q-306, Rev. 0, "Fatigue Analysis of Recirculation Outlet Nozzle", July 2007.

1.Calculation VY-16Q-308, Rev. 0, "Core Spray Nozzle Finite Element Model"3), July 2007.

~Enteigy NRC Public Meeting, 1/8/2008 554

>itergy R-,eferene

15.

Calculation VY-1 6Q-309, Rev. 1, "Core Spray Nozzle Green's Functions" G~dG~dfDecember 2007.

16.

Calculation VY-1 6Q-31 0, Rev. 1, "Fatigue Analysis of Core Spray Nozzle",

December 2007.

17.

Report SIR-07-438-NPS, Rev. 0, "Comparison of Component Stress Difference to Total Stress Intensity for Recirculation Outlet and Core Spray Nozzles", December 2007.

18.

Calculation QA-2000-1 02, rev. 0, "Evaluation of Turbine Roll Event:

ANSYS, vs. FatiguePro", May 1995.

19.

"Reactor Thermal Cycles for 60 Years of Operation," Attachment 1 of Entergy Design Input Record (DIR) EC No. 1773, Revision 0, "Environmental Fatigue Analysis for Vermont Yankee Nuclear Power Station," July 2007.

i:;'zý20.

EPRI Materials Reliability Program: Second International Conference on

_____Fatigue of Reactor Components (MRP-84), "Fatigue Evaluation of a BWR Feedwater Nozzle using an On-Line Fatigue Monitoring System", March 2003.

21.

Shigley, Joseph E., "Mechanical Engineering Design," Third Edition, McGraw-Hill Book Company, New York, 1977.

7='-Entertgy NRC Public Meeting, 1/8/2008 555