ML20113H499

Rev 0 to Licensing Topical Rept Nutech Feedwater Nozzle Bypass Leakage Monitoring Sys App:Results for Browns Ferry Unit 3

ML20113H499
Person / Time
Site:	Browns Ferry
Issue date:	09/05/1986
From:	Froehlich C, Kleinsmith M, Taylor M NUTECH ENGINEERS, INC.
To:
Shared Package
ML20113H494	List: ML20113H493 ML20113H496 ML20113H499 ML20113H505
References
XTV-01-105-R00, XTV-1-105-R, NUDOCS 9208040115
Download: ML20113H499 (12)

Text

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XTV-01-105 Revision 0 i September 1906 l' I l e fi u m n e r 165.1501.0105

, LICE!1 sit 1G TOPICAL llEPOflT 11UTECil PEEDWATEll 110ZZLE DYPASS LEAKAGE M0111TORIt1G SYSTEli APPEt1 DIX: RESULTS FOft IIROWilS FEltitY Ut1IT 3 Prepared for Tennesace Vr.lley Aut.hority Prepared by 11UTECil Engineers, Inc.

San Jose, California Prepared by: Apjeroved by hktf d fkNo*x .Y A - -

W M. 10 Kleinamith C.. II . Proch11ch, P.E.

Project Engineer Engineering Manager i

Issued by:

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Date: bh / C/ 9 [> _

l Mones Tay1 r, J r. , P.E.

Project. Manager l

9200040115 920729 .

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' i REVISION CONTROL SHEET Licensing 'Ibpical Ibrort TITLE.ju11DI l'eedsater ibzzle DyinSG DOCUMENT FILE rdUMBER 165.1501.0105 Icakage obnitoring Syst.wn Appealix: Insults for Urcw n Terry Unit 3

/J. G. Cofic/ Technical 1.cader wcc INITIA U N AME / TITLE M. E. Kleinsmith/ Project Engineer Nff'/'

NAuf / TITLE ' N ' I ' I INI T I A .$

N AME / TITLE HAME / TITLE INiilA M PREPARED ACCUHACY CHITERIA "IM*""I AFFECitD DOC P AGt ts) nty BY I DAf t CllECK BY / DATE CHECK BY / DATE D

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n TADI,E OF _ cot 1TEtiTS Page t.0 I!!TitODUCTIO!1 A.I 2.0 DISCUSSIOli A.I 3.0 METilOD OF AtlALYSIS A.2 s l 4.0 ItESULTS A.4 5.0 PATIGUE USAGE PACTOil A.4 6.0 ItECOMMEllDATIOtlS A.5 7.0 ItCPERCllCES A.10 TADLE I A.6 TAllLE II A.6 TABLE III A.6 TADLE IV A.7 FIGURE 1 A.D FIGURE 2 A.9 s

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1.0 I t1 Tit 0 DUCT 10ti_

The feedwater nozzles of Tennessee Valley Authority's Browns Ferry Unit 3 nuclear power plant were modifled by installing triple thermal sleeve spargers. This d

modification was made to minimize thermal sleeva bypass leakage, which leads to rapid thermal cycling due to turbulent mixing of cold feedwater and hot reactor -

water. Rapid thermal cycling nas been identified as the major cause of observed cracking of icedwater nozzles, as discussed in itUREU-0619 (Reference 1).

140TECl! provided Tennessee Valley Authority with a leak-g age monitoring system (LMS) to monitor the effectiveness of the new thermal sleeves in preventing leakage. Data taken from the LMS during plant operation (November 15, 1984 to March 19, 1985, see Reference 2) was sent to _

tJUTECll for analysis. That analysis 10 now complete and results are presented in this report.

2.0 DISCUSSION The leakage monitoring system consists of four thermo-couples attached to the outside of each of thc six feedwater nozzles (one at the top and three at the bottom). These thermocouples monitor the nozzle's XTV-01-105 A.1 nutg_cj]

i.h outside temperature downstream of the thermal sleeve seal. The temperature at this location correlates well with the amount of bypass leakaget the greater the leakage the lower the temperalure. .

e' 3.0 METHOD OF ANALYSIS l

The first step in analyzing each nozzle for leakage is to group the data by reactor power level (or percent feedwater flow) and then average the data from the bottom three thermocouples for each nozzle. Each thermocouple data point is then expressed as a factor of the difference between reactor and feedwater tempera-tures. This' process is referred to as normalization gggg (see Reference 3).

T ~I FW Tg = T/C III T -T RX FW Where Tg = Normalized temperature

= Bottom average temperature TT/C Tpg = Feedwater temperature T gx = Peactor; temperature The Icakage rate may now be calculated from XTV-01-105 A.2

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. i

- T -T N

[ L" (To -T 1.5

} x 1.5 gpm (2) 1 Where L = Analytically determined 1 akage rate in gallons per minute el To = Analytically determined normalized temperature at 0 leakage T1.5

= Analytically determined normalized temperature at 1.5 gpm leakage To and T1 .5 were determined from finite element analysis of the Browns Perry feedwater nozzle configuration (Reference 5). Based upon Browns Perry data and analysis, 14UTEcli selected 0. 57 for T o and 0.12 for T1.5 d,'

in the Browns ,arry 3 leakage calculations.

Substituting T o and T1.5 back into equation (2) gives 0.57 - T 0.57 - T L * (0.57 - 0.12

• 1*b " 9.45 x . (3)

Therefore, equation (3) is the equation for bypass i

! leakage around the triple-sleeve spargers at Browns i

Perry 3.

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4.0 RESULTS

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i The analysis of the LMS data at Browns Ferry 3 revealed that no significant bypasa lenkage is present at any of the feedwater nozzles. This result var to be expected d since these spargers are newly installed. Tables I, II, and III summarize the resu'*.s of leakage calculations done at 100%, 90%, and 80% ftedwater flew rates _

(Reference 4). t1egative values should be interpreted as zero leakage.

5.0 FATIGUE USAGE FACTOR Since there l's no leakage around the thermal sleeves, ELM 893 there is minimal contribution to the fatigue usage tactor due to rapid thermal cycling. Figure 1 is a ple ;

of fatigue usage factor vs. constant leakage over a 40-year period for the Browns Ferry 3 station (based on the Thermal Duty Map presented in Table IV, from Reference 5). As can be seen from this figure, the contribution to the fatigue usage factcc is quite small for leakaga rates of about 1.0 3pm or less. However, $

the fatigue usage factor increases rapidly for leakages above this level. The usage factor for a leakage rate of 1.5 gpm is 0.543 after 40 years, which is less than the code allowable value of 1.0.

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d.h figure 2 presents a graph of IJiS temperaturen versus leakage (Reference 4). As the temperature falls below about 390*F, the correlation 'with leakage bcsaks down.

If the temperature does fall below 390*, the leakage is 8

quite high as is the u sage factor.

6.0 RECOMMEt1DATIOtJS, The data analyzed through March 19, 1985 indicates that, up to this date, the newly installed triple sleeve spargers are not leaking. However, continued tempera-ture monitoring of the outside surface of the feedwater nozzles is important to assure that with time, any leakage that may occur is detected.

Data should be taken on an hourly basis when the plant ,

is in start-up or shut-down, and bi-weekly when the plant is at or near full power. This data should be plotted versus time, to determine trends of thermal sleeve seal performance. 5t ep changes in the calculated leakage rate may be an indication of a malfunction in the LMS.

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. I' Table I LEAKAGE CALCULATED AT POWER = 1001 (Reference 4)

NOZZLE LEAKAGE (GPM) 1

- -0.209 2 -0.107 3 -0.311 j

4 -0.470 5 -0.362 6 -0.107 Table II LEAKAGE CALCULATED AT POWER = 90% (Reference 4)

NOZZLE LEAKAGE (GPM) 1 -0.191 2 -0.056 M 3 -0.288 4 -0.456 5 -0.288 6 -0.049 Table III

' LEAKAGE CALCU,ATr.D L AT POWER = 80% (Reference 4)

NOZZLE LEAKAGE (GPM) 1

-0.247 2 -0.065 3

-0.299 4 -0.462 5 -0.306

-0.072, 6

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l Table IV

/ BROWNS PERRY PLANT SPECIFIC TiiERMAL OUTY MAP (Reference 5)

Region,  % Power flours / year Rx Temp, FW Temp.

' 372.00 I 100.00 5520.00 539.00 2 95.00 1195.00 539.00 360.00 3 80.00 373.00 539.00 350.00 4 70.00 302.00 539.00 337.00 5 50.00 94.00 539.00 315.00 6 50.00 3.00 539.00 285.00 40.00 42.00 539.00 305 00 7

8 40.00 14.00 539.00 240.00 9 32.00 14.00 539.00 185.00 10 23.00 12.00 539 00 175.00 11 23.00 8.00 539 00 120.00 12 15.00 16.0C 539.00 120.00 13 5.00 64.00 530.00 120.00 14 5.00 14.00 470.00 120.00 15 5.00 10.00 360.00 120.00

$N$$

16 5.00 40.00 240.00 120.00 17 5.00 40.00 512.00 210.00 18 5.00 29.00 298.00 210.00 19 5.00 13.00 536.00 308.00 _

20 0.00 43.00 340.00 300.00 21 1.00 .40 360.00 350.00 22 2.00 1.78 350.00 190.00 23 2.00 1.38 340.00 125.00 24 2.00 .25 330.00 'O.00 2.00 1.60 400.00 190.00 25

'6 3.00 .38 340.00 160.00 0.00 900.00 70.00 70.00 41 k

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figure 1

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(Reference 5)

' 40 YEAR USAGE FACTORS AT COHSTANT LEAKAGE d a t h

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1Fi 1.2 5 1.5 0 0.25 0.5 0.75 1 4

LEAKAGE (GPM) s XTV-01-105 A.8 nutg.g}]

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7.0 REFERENCES

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I 1. NUREG-0619, "DWR Feedwater Nozzle and Control Rod Drive Return Line Nozzle Cracking," April 1900.

2. Unit 3 Leakage Monitoring System and Main Steam / Reactor Feedwater Pressure and Temperature Data, November 1984 through March 1985,, File No.

~

165.1501 0016.

3. " Licensing Topical Report - NUTECil Feedwater Nozzle Bypass Leakage Monitoring System," Rev. O, dated October 1982, File No. 165.1501.0018.

4. NUTECli Calculation Package, " Drowns Ferry Unit 3 Leakage Monitoring System Leak Rate Prediction,"

Rev. O, File No. 165.1501.0303.

5. " Structural Integrity Assessment of Browns Ferry Peedwater Nozzles," Rev. O, Document No. XTV 008, File No. 165.1500.0017.

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