ML20206F903

Tube Fatigue Evaluation:Response to NRC Questions

ML20206F903
Person / Time
Site:	Point Beach
Issue date:	11/14/1988
From:	Hu M, Lagally H, Pitterle T WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
To:
Shared Package
ML19295G689	List: ML20206F878 ML20206F881 ML20206F903
References
WCAP-12043, NUDOCS 8811210386
Download: ML20206F903 (31)

Text

_ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ______ __ _

Weep Propnetary Class 3 e

t WCAP.12043 o

,e 4

e Point Beach 2  :

Tube Fatigue Evaluation : Response to NRC Ouestions AUTHORS : H. LAGALLY M. HU J. HALL i

. APPROVED: '/_'/L M [ d

. T. A.PITTERLE, MANAGER

. STEAM GENERATOR ENGINEERING WORK PERFORMED UNDER SHOP ORDER XARD 88047 t NOVEMBER 14,1988 h

l WESTINGHOUSE ELECTRIC CORPORATION SERV!CE TECHNOLOGY DEPARTMENT '

4 P. O. BOX 3377 PITTSBURGH, PENNSYLVANIA 15230  !

f l

8811210386 881117  ;

FDR ADOCK 0$000301  ;

O PDC ,

l

Westinghouse Proprietary Class 3 a

l 4

Introduction WCAP 11666 documented the first tube fatigue analysis performed for any plant after identification of flow peaking effects as a significant factor for the tube failure mechanism for the North Anna R9C51 tube. This first analysis represented a conservative assessment of the potential for tube fatigue similar to the North Anna tube, based on the plant operating data, eddy current data and the basic air model ,

flow tests available at that time. The NRC noted that the methodoiogy of fatigue analysis, as described in more recent reports for other plants, has been significantly enhanced since the first implementation for the Point Beach 2 plant, and that these enhancements should be reflected in a critical review of the Point Beach evaluations in response to the specific NRC questior,s.

All facets of the tube fatigue analyses have been enhanced in the course of performing a number of these analyses during the last year. The interpretation of eddy current data for the presence and location of AVBs in the U bend region of the tubes has become essentially routine, and capable of differentiating the AVDs in noisy signa!3. The

. projection method for determining the position of the AVBs based on the eddy current data is routinely applied with a high degree of confidence, augmenting the eddy current evaluations to determine the AVB positions between two adjacent tubes in the same column. The data base for flow peaking considerations has been significantly expanded to provide specifically applicable peaking factors or bounding values for many different AVB configurations around the tube of interest. The tube performance analyses ( eg stability ratio, stress ratio and cumulative fatigue) have been enhanced and standardized to provide the bounding conditions for any tube.

Application of the enhanced evaluation methods for Point Beach 2,in response to the NRC questions, re affirms the prior conclusions documented in WCAP 11666 in regard to the need for corrective action : No tubes have been identified in this re evaluation as potentia'ly at risk and requiring corrective action. The overallimpact of this re evaluation on the conclusions of WCAP 11666 is minimal, and is summarized following the response to the NRC questions.

The specific NRC questions are included as an appendix to this report. The responses to these questions follow.

1 Westinghouse Proprietary C! ass 3

Westinghouse Proprietary Class 3 Q1. WCAP 11666 does not specifically nJdress the subject of uncertnIntles in the A VB insettlon depth estimates. For A VB configurations leading to potentially significant penking factors (which we understand to include flowpeaking factors potentially > 1.0), AVBs in more recent Westinghouse analyses have reportedly been positioned with!n measurement uncertnIntles to maximize the flow peaking factor estimate. Were the AVBs positionedIn a similarly conservative manner during the Point Beach analyses? [11not, we believe that potentially IlmIIIng tubes should be re assessed to ensure that conservative flow peaking factors have been incorporatedinto the analysis].

Westinghouse performed a review of the original AVB position analysis to identify the regions where tubes could be subject to increased flow peaking due to changes in the AVB positions to account for uncertainties in the AVB position determination. The tubes identified in this review were in columns 2 through 12 and columns 36 through 46 in S/G A, and in columns 2 through 9 and 43 through 50 in S/G B. The flow peaking factors for all other columns were considered to be unaffected by application of reasonable uncertainties to the AVB positions.

The review included re examination of the eddy current data for the tubes in the

, columns identified as well as application of the latest AVB position projection techniques. The eddy current interpretations for the tubes with potentially increased peai<!ng factors resulting from the application of AVB position uncertainties in the column ranges noted above were separately reviewed by two analysts based on the experience accumulated in similar analyses of a number of other plants. Only a few "AVB visible" calls were revised from those shown in WCAP 11666, which were originally made during the 1987 outage, in some instances (eg column 39 in S/G A), the number of AVBs was siated only as greater than 2, because the signals could not be explicitly separated (see Figure 1).

Such cases sometimos occur when the apexes of adjacent AVBs are nearly tangent to the tube being measured. For the tubes in column 39, multiple AVB signals were visible, the outside two very clearly, and the inner AVBs as large, apparently overlaid signals. Since the AVBs Inserted furthest were discernible, no additional effort was made to separate the signals of the less inserted AVBs.

The AVB position maps included in WCAP 11666, shown in Figures 2 and 3, were based primarily [

, ]a c direct eddy current readings were unavailable for smaller rows. The original '

projections were typically based en arc length data from tube rows [

2 Westinghouse Preprietary C! ass 3

Westinghouse Proprttary Class 3 i e

. ]a.c of the individual projections in a column.

As noted in paragraph 6.4.3 of WCAP 11666, projections made from (

ja.c Consequently,the AVB projections reported in WCAP 11666 were conservative from a tube support perspective, in that the AVBs were considered less inserted than the actual condition in the bundle. '

The current projection methods utilize the projection from the (  ;

ja.c as the best prediction of the actual AVB position, if  !

projection from successive rows in the same column result in good agreement with the

[ Ja.c the AVB insertion depths are well established. If the successive row projections differ significantly( Ja.c, the AVB insertion depths are evaluated in a conservative manner. To maximize the row to row consistency in the projected AVB position, the [

}a.c AVB position are generally utilized in the current projection methods,  ;

The revised AVB positions, based on ths critical review, are shown on the AVB maps, Figures 4 and 5. The areas considered and the revised AVB positions are shown  :

, inside the outlined areas on these maps. Figures 6 through 9 provide the expanded '

. detail for the revised AVB positions.

S/G A Evaluations t

The results of the evaluation of tube R10C39 in S/G A are shown in Figure 6. Although l the data for the row [ ]s.c were noisy , the position of the j outermost AVBs was visible and indicated that the row 10 tube is supported, i consistent with the data from R11C39. The data for the tubes h columns 38 and 40 r supported the column 39 projections which indicated that the R10C39 tube was  !

, supported. Further verification of this conclusion was provided by examination of the ,

j 1980 inspection dath which provided AVB locations in tube R10C39 prior to plugging of this tube. The conclusions with regard to R10C39 cro that this tube is supported by  !

AVBs on both sides; therefore, this tube is not susceptible to the fatigue mechanism.

The AVB positions between columns 41 and 40 in S/G A shown on Figure 6 are based f on the[ ]a.c available in these columns. The tubes in these columns are suppcrted by the AVBs  ;

and are not susceptible to the fatigue mechanism.

• l

\

• r j 3 Westinghouse Preprietary Class 3 t

t

W:stinghouse Proprttary Class 3 l

^

Figure 7 shows the results of the AVB position evaluations for columns 2 12. Very [

good consistency of the projections was found among the adjacent tubes in all rows, to support the final AVB positions shown. The [  ;

ja.c flow peaking factors for the tubes in these columns.  ;

WCAP 11666 Identified tube R11C4 as the limiting tube in the Point Beach steam  !

generators. The impact of the re evaluation on this, conclusion is discussed below,  :

following the response to the NRC questions. l 1

S/G B Evaluation i

The positions of AVBs in the region of plugged tubes in columns 45 48 were  !

a determined by projection in the original analysis, based on data (

Ja.c. The projections for these columns were repeated based on available data for rows [ ja.c, and are shown in Figure 8. Both the "AVB visible" data and the projections are very consistent in this region, indicating uniform alignment of the  ;

i AVBs. The positions of AVBs adjacent to column 46 are based on the projection data i from the row 13 tube. These positions are confirmed by the original projections from  !

i the row 17 and 25 tubes which were 10.2 and 10.8 respectively. Similarly, the projected position and uniformity of the AVB positions in columns 45,47 and 48 are confirmed by the eartior projections, it was concluded that the tubes in this region of

. S/G B are supported by the AVBs and are not susceptible to the fatigue mechanism.

l The results of the re evaluation of the tubes in columns 210 are presented in Figure 9.

Tubes R10 and R11 in column 5 were identified with AVB positions which could lead to flow peaking. Tube R10C5 is shown unsupported, consistent with WCAP 11666.

J Tube R11C5 is shown to be supported at the tube centerline, however at the limit of t;cceptability based on the projection techniques. ( Note that the projections are based )

on the AVB centetilne relative to the tube centerline;therefore, a [ I

]a.c support !

of that tube.] This conclusion is supported by the [ Ja.c from l

column to column, and by the [ ]a.cof the AVB visible calls. For conservatism,  ;

tube R11CS is included here for re evaluation of flow peaking , stability and stress l ratios, and cumulative fatigue usage.

l f

i Summary of AVB Position Evaluation I Re evaluation of the AVB positions in S/Gs A&B in areas where position uncertainties )

could lead to significant flow peaking factors was performed. The areas examine  !

!- Included areas of uncertainty resulting from ambiguities in the 'AVB visible" calls and l 1

l l .*  ;

! (

i 4 f I

Westinghouse Preprietary Class 3 l

I -

W:stinghouse Propri:tuy Class 3 l l

l

~

resulting from clusters of plugged tubes. Areas not re evaluated were considered not affected by uncertainties in the AVB position eva!uation either because application of the uncertainty would not result in a need for corrective action, or because the AVB position was established by the "AVB visible" calls. The AVB positions within the areas considered were established by consistency of projections between adjacent columns, consistency of projections among multiple rows in the same column, and by consistency of the "AVB visible" calls from the eddy current review.

No tubes were identified in S/G A where uncertainties in the AVB positions existed which could lead to significant flow peaking factors, although the re evaluation uf the AVB positions identified that tube R11C5 is not supported, in S/G B, re evaluation of the AVB positions resulted in an AVB configuration which could lead to flow peaking at the unsupported tube R10C5 which is consistent with the WCAP 11666 evaluation.

The S/G B tube R11C5 was not identified in WCAP 11666 as unsupported, but is conservatively included here for further evaluation, even though it is shown to be supported by an AVB.

.QL.The licensee's letter dated March 25, 2988 notes that more recent estimates since issuance of WCAP 11666 Indicate a flow peaking factor of 1.47 for North Anna tube R9C51, compared to an earlier estimate of 1.36. The effect of this change is to reduce the "relative"stability ratlo

. estimates for tubes In Point Beach. The Afarch 25,1988 letter, however, does not address revised all test data for Identitled AVB configurations relative to what were considered In the WCAP 11666 report. For example, AVB configuration No. 3In Table 7 3 of WCAP 11666is now believed to have a flow peaking factor of 1.11 rather than the value of 1.0 assumedin the WCAP 11666 analyses. Do stability rallo, stress ratio, and fatigue usage factors for the limiting tube locallons continue to be acceptable If the latest peaking factor data are used?

The tubes in the Point Beach 2 steam generators were evaluated to determine the maximum permissible relative peaking factors for the row 8 12 tubes. Maximum relative flow peaking factor [

]a.c. The maximum relative flow peaking factorincludes [

]3.c forR9C51 in North Anna. The results of this analysis are shown in Figure 10. This figure is used to define bounding values of local flow peaking due to AVB configuration. For example, the bounding value of flow peaking for row 10 tubes is approximately [

, ]a.c. The allowable peaking factor for the most limiting row 9 tube is ( Ja.c peaking factor, and all 5

West.nghcuse Prept etry Cfass 3

W:stinghouse Proprbtary Chas 3

. row 12 tubes, except in columns 2 and 91, are shown to be supported. ,

The most limiting tubes in the range of columns considered in this re evaluation, in

. either S/G - A or B, are the R10 and R11 tubes in C5 in S/G B as a result of the applicable flow peaking factors for the AVB configuration adjacent to these tubes.

However, the flow peaking factors for the AVB configuration around these tubes are less than the allowable peaking factors of [ ]a,c respectively ( see the Re evaluation Summary following Ouestion 4 below). Consequently, the stability ratio, stress ratio and fatigue usage factors continue to be acceptable when the updated peaking factors (compared to those in WCAP 11666) are used.

t QL Consider tube R10C39In Figure 6 6 of WCAP. The AVB configuration pictured for this tube looks very much like the AVB configuration for tube R9C47 at North Anna (see Figure 2 C of WCAP 11799). What is the justification for considering a flow penking factor of less than 1.47 for tube R10C39 at Point Bench 2, S/G A ?

The AVB position evaluation discussed above specificallyincluded tube R10C39 in response to the NRC request for additionalinformation. This tube was shown to be supported by detailed projections from surrounding tubes, based on a detailed AVB projection analysis utilizing eddy current data from the 1987 outage. The updated "AVB visible" data and the projection data for the C38,39 and 40 tubes all indicated that the l' R10C39 tube is supported.

Tube R10C39 support was confirmed by examination of the eddy current data for this tube from the 1980 outage, prior to plugging of the tube, which indicated [

]a,c. Projections based on the AVB location data resulted in an AVB position between rows 9 and 10, consistent with the projections based on the 1987 data, t I

L i

i l

[

l i

6 l I

We@;%vse Preprietary C' ass 3 l

Westinghouse Proprietary Class 3

. Q4. During October 25,1988 telecon with the staff, Westinghouse representatives Indicated that In some Instances, flow peaking factors for a given AVB configurallon may have been estimated based on

. Interpointion of nit test data between nIr test data obtnIned for different identitled A VB conf lgurations. Please describe the methodology and validity of such an Interpointion. [ Absent adequate justification for such an approach, the statt believes that flowpeaking factors should be determined directly from nit test data foridentIIIed AVB configurations which conservatively envelope the actun! A VB configuration being assessed].

Interpolation between different cases for which air test data are available is not utilized in this evaluation to establish flow peaking factors for the limiting unsupported tubes.

The flow peaking factors for all of the AVB configurations for potentially affected tubes in Point Deach 2 have been determined directly from air tests of the AVB configurations. The configurations tested which are applicable to Point Beach 2 are shown in Figure 11.

In some cases, detailed resolution of AVB positions or flow peaking is not necessary.

For example, Row 9 tubes in Point Beach 2 must have [

]a.c that for North Anna tube R9C51 to be susceptible to fatigue, as shown in Figure

, 10. It is clear from the AVB maps, Figures 4 and 5, that AVB patterns with very high

. flow peaking do not exist in Row 9, and that for these tubes, peaking factors can be estimated to demonstrate margins against the acceptance limit. In a similar manner for other tubes, Figure 10 is used to guide the needs for resolution of flow peaking factors.

05. Discuss basis for assuming a flowpeaking factor of 1.0 for tubes located in columns 2 and 91, rows 10,11, and 12.

The evaluations for peripheral tubes in columns 2 and 91 involve both peaking factors and effective velocity considerations. The velocity of the flow past the Row 10,11 and 12 tubes in columns 2 and 91 is catculated to be less on the outside of the tube than in the gap between columns 2 3 and 90 91. Experimental work has been performed l for fluidelastic excitation of tubes with non uniform fluid velocities, side to side (1),

although the gap velocity in these test was less than the wall velocity (ie the reverse of flow condition in the S/G). The effective velocity for fluiuelastic excitation is [

ja.c. This results in an interpretation that the [

, ]a.c the critical velocity for the case of uniform gap velocities . This interpretation is consistent with the 7

Westoghouse Prepr;etry Ctass 3

Westinghouse Proprietary Class 3 j

. experimental results. [  ;

3a. con penpheraltubes.

. Various flow peaking sensitivity tests show that AVB depth variations on only one side  :

of the tube being evaluated [ la.c. This is the condition for  !

peripheral tubes shown for Rows 10,11 and 12 in columns 2 and 91 in Figures 4 and i

5. The flow peaking factor tests shown in Figure 11, cases 6a and 6b, show the [ i' la4 for one sided AVB depth variations on the peripheral tubes. Based on the above, peripheral tubes are evaluated with ( l i

la.c, }

[

r I

1 l

1.

[

I l

t i  !

I r

i l

s  !

.- t i

{

B l,

I Westinghouse Preketry Ctass 3

Westinghouse Propetary Class 3 Re-evaluation Summary :

The AVB positions based on the application of the current methods are shown in the AVB position maps for S/Gs A and B in figures 4 and 5. Only those areas of the original maps in WCAP 11666 were re evaluated where there was the potential for significant flow peaking factors when an assumed uncertainty was applied to the AVB positions, or where there was ambiguity in the published AVB positions due to plugged tubes or otherwise Inconsistent eddy current data. The re evaluation included re analysis of the eddy current data for the tubes in the columns identified, which are shown on figures 4 and 5 within the outlined areas.

The significant changes resulting from this review were:

, a) Tube R10C39 in S/G A was shown to be supported by an AVB, based on projections utilizing 1987 data, and confirmed by direct observation of AVBs in tube R10C39 from 1980 data.

b) Tube R11C5 in S/G A was determined to be mar 0 lnally unsupported, based on

.' updated projection data.

. c) Tube R11C5 ln S/G - B was determined to be supported, however at the limit of the projection method criteria for support, and was therefore conservatively included for further evaluation for stability, stress and fatigue.

The unsupported tubes, including those in the areas not re evaluated, are summarized in Table 1.

The local flow peaking factors for the unsupported tubes weru determined from air test which simulated each configuration. The configurations tested and the resulting flow peaking factors are shown on Figure 11. The applicable peaking factors for the unsupported tubes are also given in Table 1.

The relative stability ratios of the tubes in rows 8,9,10 and 11 were calculated. The fluid velocity was based on WCAP 11666 thermal hydraulic anal /ses, including application of the effective fluid velocity for the outer tubes as the [

]a,c gap velocities calculated for these tubes.

The revised relative stability ratios, including the applicable local flow peaking factors from above, are summarized in Figure 12. A relative stability ratio of 1.0 is the reference condition, tube R9C51 of North Anna. The horizontallino en Figure 12 at 9

West:nghouse Ptcpr et.vy Class 3

s-Westin0 house Propr'ctary C' css 3 i

(0.9]a.c relative stability ratio is the acceptance guideline for tube stability ratios. The relative stability ratios for the unsupported tubos are given in Table 2. None of the unsupported tubes exceeds the stability ratio guideline.

Stress ratio is defined in WCAP 11666 as the ratio of the stress in a given tube compared to the stress in tube R9C51 of North Anna. Calculation of the stress ratio takes into account the (tube specific parameters, plant specific parameters as reflected

! in the relative stability ratio calculations local flow peaking and a 10% margin l relative)a.c to the North Anna R9C51 tube condition. A stress ratio [ la.c indicates l

that the tube will nc4 be susceptible to fatigue.

The stress ratios for the tubes in rows 8 through 12 are shown in Figure 13. All of the l

row 11 and smaller tubes have a stress ratio less than 1.0, and the unsupported tubes in row 12 (columns 2 and 91) also have stress ratios less than 1.0. Furthermore, all of the tubes considered in this re evaluation have stress ratios less than the maximum stress ratio for the limiting tube reported in WCAP 11666.

The limiting tube resulting from the re evaluation based on current methodology is tube R11C3 in S/G A,instead of tube R1104 in S/G A originally defined in WCAP 11666,

- Figure 8 7. The difference is the result of the peaking factor applied to these tubes.

Originally, a conservative flow peaking factor was applied which was greater than defined by representative cases,6a and 6b, of Figure 11. Air tests of the detailed configuration for the tubes in row 11, columns 3,4,and 5 Indicated that the peaking factor for these tubes was negligible (see Table 1 ).

The results of the re evaluation of the Point Beach 2 tubes confirm the overall conclusion in WCAP 11666, that the tubes in Point Beach 2 are not expected to experience a fatigue n.pture at the top support plate similar to that which occurred in R9C51 tube in North Anna, and that no action is required to preclude such an event, c

References:

(1) Connors, H.J.,"Fluidelastic Vibration of Tube Arrays Excited by Non uniform Cross Flow", Flow induced Vibration of Power Plant Comoonents 1980,ASME, pp93107.

10 West.nghouse Preprietary C' ass 3

Westinghouse Proprietary Class 3 1able 1

. Flow Peaking Factors and Peaking Ratios for Point Beach 2 Steam Type of AVB Peaking l'eaking Generator Row No, Column No. Insertion Factor F atio abc i

l l

l l

I

~ ~ g 11 Westinghouse Proprietary Class 3

4 Wor.inghoves Proprietary Class 3 t

. Table 2 Summary of Stress Ratios for Unsupported Tubes for >

Point Beach 2 S/G Row No. Column No. Rel.SR*FP Stress Ratb A 9 85 a4 65 ,

10 91 t 54 16 i 15 j L

. 11 91

. S.4.3 2 i

. B 8 86 ,

68  !

20 15 14 9 89 37 9  !

l 10 91 5

2 11 91 ,

5 l 2 I i

12 91 2

l t

12 WesMghocse Preprietay 01:5.3 i

I

4 4

Figure 1 Eddy Current Trace Showing Clustered Signals Near Tube Centerline

- CH 4 NatT + - CH 8 MT + OW#E.NO - 9 SG 19 ROM 13 COL M W O!SPUW L 04Dee - 8 FE9 10 kHe SP584 29 ROTATION - 313 DED N LDT STRIP 05NT g FRES 0 988 -- 4V 100 kHz l SP584 58

_'. .;f. . ROTRTI(34 - 118 (ED 4 4

. . .. r. ;r. ~ . . . . . . .- 51. . .

3* 8 g

it!(DfT STRIP 045tT 7.g CwDe - ev

. - . - _ ._. rnEn to uHe gI.. tiP9N 29 m, g,g A0TRTICD4 - 313 DED l SWTD4 CODFICMWITICD4 i 14DE - WIS-40-871

_ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ e of N 8 9 J5:54 PM

. . . . . . . . . . . . . . . . . . . . ....._ OCTWR 91987

,i CO LO

__......l.....-- i a a 4 s 6 7 e m.

s i i a

~

,. i 5 PU447 LHIT SA) LEO DATE BUC 23e89 PO!HT BERO4 2 A_ ,,O IT1.E  !?/9947 Legend:

1a,1b - Most inserted AVB (clear signal) 2a,2b - Less inserted AVB (clear signal) 3 Overiapped AVBs e

l

- l 99999 3

. . _ O t P e9999 s -e~-OY eeOce -

99008  : - -

~O GeGOO Y

999OO  :

9999e i ___ ,,Q~,O O O O il_

99999  :

_ i 99996 OOOOO ; : -

@@G99  :

-~ 999QO  : 99000 -  !

9999@ i 90Q 3 000 -T 99999  : QO 0~ 0- G O O Ill 99990 e OO e 99 GOO -  ;;

8999@ c 09 : : 99Q00 e s 9999@c GO : 98000  :

~

l -~~

7 c OO s 9e000 : i i !J gE'@ee999@

g 999907- 000 : : 99000 =  ! lI

~

9999@ n GGO : ; 99 GOO :

• 3 lii e;N 9999G =

OGO s i ~ 99@OO ((_

5 l '

.- gdeeeee =

Oee : ! _eeeee 1 1 _ a l 1 .

999ee n GOO 1L eeeOOy I p!

[wxto 5.~9 9 6 0 G 2  % OOO e 99 Qfp 0  !

I gj j 9999G 2 OOO G e OJd O E I gg g OOOOG a s OOO s 99900 ALI l ga 99999  : Q09  : 99900 a g 3 8

9999@

s OOO a 99900 I i 5 } } ,

9999G 900  : 99900 1 9999@ s  :

__ e 4

'I f 990GO OS O G OM O  : j..

Q990-O - 9 0 0~ 0~ O 1 QQ9Ge a 99900  : : 999e0 _ 1 __

9999G  :

99990 1: _.gpOOOO i t 99GGG 99999 L O 1 1 i OGOOO n !

_ 99990 s 3 O i P

.. OOOOO s -

99999 i__nt, O G 99990 s O a e

,, a : e - - 3  : 3 .. ~

i , j $  :

i - i c : i m '1 i

,- - - . . . . , - - . , . - - - - - . , , - , - , - ,.n, ,,_-_,--.n. , . _ _ -

k l

~

Weeee =

e -

. GOGGG  : GeGOG : 89 8G ~

i' 88898  :: eeee@ i__eBe@@ ~

GG898 :s eeeGe  : GOG -

~eeeGG :s GOOee  : GGG -  ;:

Geeee  :: eeeee : : eee -

eteeG 311 8890@  : eeeGG -

Ge888  :: G G GB G : 8889@ -  :

@@@@@ : R SG@@@  : @@@@@

e88Ge c  : 9888G s  : EGG @e e  : --

m  : s GO8eG : @@@GG  :

@GOGGG OGGeG : : 99GG@  :  : GGGGG

{

3

@.$$ GOGGO  :  : GOGGO : : 99888  :  ;

I 3

eeeee = = See t ; : -eesee = 2 l i i o%b eeee  :

e e e e e.

eeeee =

el e * = = = ... ; eeeee -

1 2 3

~ _

35' m

.O : : eeGee *

{.!

e E.GGe@@

eeeee n :

^

ee : eeeee s

1 51 s

eeeee G8GGG s : W8 ee 2  : eeeee -  !

it ]i  !

s GeGee s OGeee  : 1 e eeeGe l__ GeeGO  : eeee9 j j a a GGGGO s GOG.G a 80880 a =

eeee& eeeee  : eeeee n

, j g } ,

80808 __ GeeGG n Geese  :

i

'W888G  : - GeeGO  : G88e6  :

'GGGGG i i GGGGO : 0 88989  :

GeGee  : GGGGG : ee.eG n 1g

'88098 }:

GGGGG : : GeeGG .: __ f !} l Oe@GG : GGG8- s 9888@ : '

8t g

' EGG- LU8 O@@GG i i - s s eeGe@  :

e . __ eeeeG  : : : GGGGG 1 1 880 _

e - - e e .. e  : e . .

, , , } i-; } i -~ i }

O 8(JFO OI:III O= .-

E' Me =

sae9Oe IR G~o ~6F6~- ~

e9eee 99996

_soeGe

~O0088 wesee 4 O~ O O O O

=- -

999G@ : : ~gT-ygTdrT-'t . O O O O Ge99O : 9900  : ~OOO -

999GO : 9090  : ~~OOO ~

le l "e ~~-SOO GO9GO l_-[ -@e900 $

99999 1 __ .--O@ l ,,,~,,,- G O O ;_ j e99998  : ~~OO s ! - Q O O 'e-3999GO

99999 7 7 "e .OOO

• e99ee E~_~_ eOcOO i . . . 00 i "

p*o.9.e s _ .000e 1 , m yrr -

j i 999G@ c 09GO@ c il GOO  : 1

' i 15 $ 9999@ i-~ ~~~O@ i il @OO e I i s j,3 8999GO - ~ ~ G"O'. WI GOO  : 5 3

p 9999@ n @~ ~ O O S : B .l66800 : a f l

}j@9OOO  :  : 0~ 0~ O O O  : 198860 I

(( !

g99999 :a : 9900@ s 166800 e I g{ j 5 99999 s QGOOO a IMO O 1_1 !

99999  : 99000  : 19 8 Q O O a l -

999QO a OOO I99800  :  : 1 I 999Q@  : 998  : 199900 i-- ! l 99999 s  : OOO s 199990  :  !

d

• 999GO Q9999  : 199890  :

ll 9999@ : : 99908  : :199999  :

99998  : T-3 9 9 9 0 : 190090  :

999QO : 99998  : 1600  :  : f GGOOO : ~

9999@ 3 IOOOOO : i l .

OOOOO 5_._ 999Q9 s 199990 a f G 99998  : le6999 s e e : e - -

, g ~-...

3 3

.. s

, , , 3 r s , , , 3 1; i-i lls l

C")@ @ 9 @ "

6-:~ .. .

@@@@@ : : GeeGG i_ ll e c e @ G ~_ s

@eOSO  :: OG88G i_lI,,Q,@ 9 G G 2 .  :'

eGee@  :: eeeee teseee 2 s

@@@@@ s  ; OOGee s_l1.,~ Q- G G G I i eeeee  :; 68808  :

-- 3 "0-GG@ l ~

9080e  : : : 889eG 1 i@,.(16GG 2 a 88888  :: OGOOG 2 808e8 e : GGGGG i__.lQ.@h,D.ees

Ll_8 C _G O 2 eeeeGe: ~

_4OGGG i_liL G a & R G _1 ..

$eee@@

_::: GGeeG I@@@@e  :  :

• [eeeGO ::  :

'"G'W'G'G~G'"'"""! O e e e G f.

en'eeeee Gleeeee c  :

eeeGO eseGe leee@e 188800 I

3 1

jii - e e e e e 5 r: eteet i: i

!GeeGG  :  : 5 3

ej8eeeee  :  :: Getee  ? le888e

• a f I

'31 eeeee _eeeee i: ?leesee

: 5

}!  !

'aE eeees l e : Q_O S,G O *188888 -

I v{ j

) 'G88G9 m

GOGGe 2 !O8GOG  ! if alt-

%eeeGe a '~G'GiFG'O'Y'""'I e e e e @ R l jj

~eeee n seeee 2 :le e e e e a y qp

.eeee  : GeeeG  : leeese = .

GeeGO : GeeGO  : :l e 8 0 e G j"s{f>i

~

, l {

Geeee: OGOGG  : leGeeO  :

eeeeO  : : GGGee s qLe e e G O GGGGe : : GGGGG  : Ol e s e G e GeGGO : GGeeG  : leeGGG  :

OGGGG : GGGGG  : :leGee@  :

)fj{

Oe@@G s :

OGGGG s GG88G GGGGG 3 :

s :

Ise@eO 198889 x c

{!!g h:

,- 4 : GGGGG  : " "'

e s e e O  :  : eO@

e ~;e - - , s ~

e - -

i , i l }i i - i S l i - i $ }i

i l

I Figure 6 Point Beach - 2; S! cam Generator A C38 - 41 Detail i

46 45 44 43 42 4. 4. 39 38 37 36 1 -g

" m .

Ea o o 2

','g, ,i3; n' n. ,g

,, ., g . y g .

g - - g ...

, # 3 .. .

g ..

jm e gg .

g ..:: # ... .. m m ..

.. s g - - - g ..; .. ... ... m m ..

1.

I m 89 m

9.7 m

99 m

98 9.7 m

94 9.4 m

9.7 y 4 1.

5

,A u ^ ^ "

, e e m at i > m m 9

'Q t. ..ca t.u O Nurrber d AVDs Vasele ag Prgeded AVB Posdon (based on AVB and stee center.res)

u. 5 I inness n.i

% ,,g % gyg g Unstmoded i T6tw Ourtne is Crosstutded

Figurc 7 Point Beach - 2; Steam Generator A Column 2 - 12 Detail 12 11 to 9 8 7 6 5 4 3 2 14 l 14 4 2 - - 2 m o e lp 10 3 10 8 10 7 10.5 11.3 11 2 11. 11. II. 11.6 11.7 11.7 I 13 I2 '

10 2 10.7 10 7 10 4 11 2 11.1 10.7 to 8 10 8 11 2 112 11.7 11.7 L 1 = 1.1 4 4 3 1 0 11 11 10 2 to 7 10.7 to 4 to 4 to 9 10 8 {

_ t 12 8 L1 =3 2 L1=17 i s

j Of 10 t !D ," f f '

&& ] (O) I

&]()

e - *=va , , _ _

ag 3 Prosecert AVB Posson (based on AVB and hbe oratertmes) 1 15 Length of Sogle AVB Segnal Unuworsed i T@e Outano is Csosshatched l

Figure B Point Beach - 2; Steam Generator B Column 43 - 50 Detail 50 49 48 47 46 45 44 43 14 MA NA 10.3 MA gA 9.7 i

b N '

D l; " 10.1 98 10 2 .? I S.7 99 99 33 9.8 9.8 l

L g Q G l 12 97 3o 4 99 95 9.6 97 97 j g3 l 12 l

11 -

97 II l m o e o m to 96 96 95 gg 95 to L 5 l

Numberef AVDs Valdo COnganalinsegretataan 89 Prgeded ..VP ' .dian (based on AVB and abe centerknes)

' Lt.15 Sangas AVO Arc Lor.gth i Unsagported a Tibe Oiano is Crosshanded iese n.s i

Figure 9 Point Beach - 2; Steam Generator B Column 2-10 Detail 10 9 8 7 6 5 4 3 2 14 ,1 14 3 4 3 4 2 4 2 13 g9 go3 30, 10.3 10.3 11.3 11 2 11.1 10.1 10 3  ;

13 1

4 3 4 3 2 4 3 10.1 12 12 96 10 2 96 10.1 11 2 11.1 11.2 10.1 10 .0 i

l

@ 4 4 3 2

! 11 94 10 9 10.0 94 98 97 10.4 30.3 11 Lt.2 2 L1 1.1 4 @ @ ' 2 1 93 99 g 10 10 93 96 L1 3.9 L t .3.3 Nurrber c4 AVDs VatAo O Onginal keerpretata j 9.3 AVB Psogeded Posamn (based on AVB & hee certerEnes) 1M M 1 22 - Sangle AVB Inecaten Length

• t.kuumorted 8 Tdae Chene is C--++M a

Figure 10 WiS -

hl AX ALLOW REL FLOW PEAKING "

m 8,C O

E b

m N

9 m

m E

N .

= ,

9 -

) i i

~

COLUMN NUMBER i ROW 8 + ROW 9 0 ROW 10 a ROW 11 X ROW 12

~

. .. womashame Prepassary cens s i

Figure 11.

. Final Peaking Factors for Point' Beach 2 TYPE OF AVB PEAKING TYPE OF AVB PEAKING INSERTION FACTOR - INSERTION FACTOR a,b,c I ( -

l h

i l

m 6

i l

• l W96f W ePrcCMeJVFCWS3 E_________

Figura 12 WIS -

REL STAB RATIO

• REL FP

&,C i

i O

k r

b

a I

I

~

! 3 ,

l IJ i E 1

• ~ ,

l 4

1 _

l l ROW 8 ~~ + ROW 9 o ROW 10 A ROW 11 X ROW 12 I

Figuro 13 WIS -

STRESS RATIO WITH DENTING \

d..c i

'i

9 1

h

, c 6

fh ii l

1 i

I

~_ . . - - -

COLUMN NUMBER ROW 8 + ROW 9 o ROW 10 A ROW 11 'X ROW 12 1

1

Westinghouse Proprietary Class 3

• e m

('

O APPENDIX NRC QUESTIONS (AS TRANSMITTED BY WISCONSIN ELECTRIC)

'O e

e I

I

.A r

< E f

1

?

l

[

• WISCONSIN Electric ro.ns cov w 231W Vich 0AN.P O BCx2046. MILWAUKEE.W153201 O

TELECOPY

. MESSAGE SENT T0: ICA T6 Elf FROM: O d , AI2ouadd

• - ~-

. DATE: 10/2*6fB8 PAGES FOLLOWING THIS COVER LETTER: Z-IF YOU HAVE A PROBLEM RECElVING, PLEASE CALL: 414- __

AND ASK FOR l

4 l

-- g y -- M W "WW BBYW FUZ REQUEST FOR ADDITIONAL INFORMATION l

Wisconsin Electric Power Company Point Beach Unit 2 IMPLEMENTATION OF BULLETIN 88-02 P Materials Engineering Branch Division of Engineering and systems Technology CCMMENT Since issuance of WCAP-il666 for Point Beach 2, the Westinghouse generic methodology has undergone a number of refinements. The staff believes that these refinements should be critically reviewed to ensure that the results and conclusions reported in WCAP-11166

. continue to be conservative. This review should address, but not necessarily be limited to, the following questions.

+

l Question 1 -

l WCAP-11666 does not specifically address the subject of uncertainties in the AVB insertion depth estimates. For AVB configurations leading to potentially significant ficw peaking factors (which we understand to include flow peaking factors potentially > 1.0), AVBs in more recent Westinghouse analyses have reportedly been positioned within measurement uncertainties to maximize the flow peaking factor estimate. Were the AVBs positioned in a similarily conservative manner during the Point Beach analyses? [If not, we believe that potentially limiting tubes shculd be reassessed to ensure that conservative flow peaking factors have been incorporated into the analysis).

Question 2 The licensee 's *.e :er dated .v.a:ch 25, 1958 notes that more recent estimates since issuance of WCAP 11666 indicate a flew peaking fact:r of 1.47 for North Anna tube RC351, :mpared to an earlier esta..ase cf j 1.36. The effect of this change is to reduce the "relative" stability t ratio estimates for tubes at Poin: Beach. The March 25, 1988 letter, however, does not address revised air test data for identified AVB configurations relative to what were considered in the WCAP 11666 report. For example, AVB configuration No. 3 in Table 7-3 of WCAP-ll666 is now believed to have a flow peaking factor of 1.11 rather than the value of 1.0 assumed in the WCAP-ll666 analyses. Do stability ratio, stress ratio, and fatigue usage factors for the limiting tube locations continue :: be acceptable if the latese.

peaking factor data are used?

guestion 3

. Consider tube R10-C39 in Figure 6-6 of WCAP. The AVB configuration pictured for this tube looks very much like the AVB configuration for tube R9-C47 at North Anna (See Figure 2-C of WCAP 11799). WP.a t is t!.e justification for considering a flow peaking factor of less than 1.47 for tube R10-C39 at Point Beach 2, SGA?

Question 4 During October 25, 1988 telecon with the staff, the Westinghouse representative indicated that in seme instancos, flow peaking factors for a given AVB configuration may have been estimated based on interpolation of air test data between air test data obtained for different identified AVB configurations. Please describe the l methodology and validity of such an interpolation. (Absent adequate l justification for such an approach, the staff believes that flow packing factors should be determined directly from air test data for identified AVB configurations which conservatively envelop the actual Ava configurations being assessed).

I l

l Question 5

?

l Discuss basis for assuming a flow peaking factor of 1.0 for tubes located in eclumns 2 and 91, rows 10, 11, and 12.

l l

_ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ____