ML20118B027
| ML20118B027 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 09/23/1992 |
| From: | Tuckman M DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9209290264 | |
| Download: ML20118B027 (10) | |
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{pngy 0u10:Powtn September 23,1992 U, S, Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 C
Subject:
Catawba Nuclear Station, Unit 1 Docket No. 50-413 Supplement to TS Amendraent Steam Generator Repair Criteria On August 24, 1992, Catawba Nuclear Station submitted a proposed Technical Specification amendment, This proposed amendment was supplemented on Septtmber 2, 4, and 17,1992, The proposed revisions change the. Steam Generatar repair criteria for Catawba Unit 1 Cycle 7 operation.
Per conversation with your staff, additional information is attached including:
The SLB leak rate basco.. LOC voltage distributicas and the nurerical average of the leak rate correlation for leakage thresholds as low as !.0 volt, and The results for voltage measurements between two inspections of the same indication using the same probe.
Catawba has not had any unforseen findings relauve to the characteristics of the Daws at the TSPs. Dents at the TSPs have been inspected using RPC and no flaws were found to have been masked by the dents.
5 The following corrections to the September 17,1992 abmittal are being provided:
The cover letter to the submittal should state that " Duke Power will evaluate the usefulness of pursuing an analysis for tube support plate displacemenc during a L.OCA
+ SSE."
9209290264 920923 PDR ADOCK 03000413 P
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U. S. Nuclear Regulatory Commission September 23,1992 Page 2 in the last paragraph on page 4 of the Duke summary of the WCAPs "non-repairable" e
should be changed to " acceptable", and the last sentence of this paragraph should be deleted.
On page 11 of the Duke summary of the WCAPs SLB leakage at EOC7 was stated to o
be 0.54 gpm. This leakage should be 0.0 gpm for the Monte Carlo or 0.01 gpm using the deterministic assessment (WCAP-13494, Table 10-5).
Catawba also wishes to clarify that a mid-cycle inspection of the SGs will be performed beginning on May 1,1993, unless specific relief has been granted by the NRC.
Very truly yours, K. 5.Fdm i
M. S. Tuckman SG4/mhh Attachment F
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U. S. Nuclear Regula'ory Commission September 23,1992 Page 3 M. S. Tuckman, being duly sworn, states that he is Vice President of Duke Power Company, Catawba Nuclear Site; that he is authorized on the part of s ~ l Company to sign and Ole with the Nuclear Regulatory Commiss on this revision to the Catawba Nuclear i
Station License No. NPF-35, and that all the statements and matters set forth therein are true and coirect to the best of his knowledge.
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M. S. Tuckman, Vice President Catawba Nuclear Site Subscribed and sworn to before me the M'd day of Se pt
,1992.
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My Commission expires:
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U. S. Nuclear Regulatory Commission September 23,1992 Page 4 xc: Mr. S. D. Ebneter Regional Administrator, Region II Mr. Heywood Shealy, Chief Bureau of Radiological Health South Carolina Department of Health Mr. Robert E. Martin, Project Manager Mr. J. Stang, Project Manager Mr. W. T. Orders NRC Senior Resident Inspector American Nuclear Insurers c/o Dottie Sherman, ANI Library The Exchange, Suite 245 270 Farmington Avenue Farmington, CT 06032 M&M' Nuclear Consultants 1221 Avenue of the Americas New Ycrk, IIcw York 10020 L
INPO Records Center Suite 1500 1100 Circle 75 Parkway Atlanta, Georgia 30339 l
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4 Attachment Supplemental SLB Leakage and EC Voltage Variability Between Inspections Sillieak Ra_1LSALqLon Numatic_qLAyfraJe for Leth_ Bate -Correlatipn Section 10 of WCAP-13494 provides estimated SLB leak rates at EOC-7 based on Monte Carlo methods and a deterministic method. The SLB leak rate at EOC-7-can also be conservatively estimated using the E0C-7 voltage distribution together with the numerical average of the SLB leak rate vs bobbin voltage correlation.
This note provides leak rates for this method as.a function of the threshold voltage between 1.0 and 2.0 volts applied for SLB leakage.
This analysis uses the reference analysis conditions of Section 10 based on RPC confirmed plus no; RPC inspected indications 11.0 volt left in service. The projected EOC-7 voltages for this case are 'given in Figure 10-1 of_ the WCAP. The reference SLB leakage correlation of Figure 7-16 is applied for this analysis. This Figure shows the numerical average leak-rate for the correlation as a function of bobbin voltage.
The EOC-7 data leading to Figure 10-1 were grouped by number of indications per 0.05 volt interval for voltages abvve 1.0 volt. Above 1.8 volts, the intervals are
-0.2 volt intervals as only one indichtion is projected in each of these
-0.2 volt intervals (Figure 10-1).
For the leakage calculations, the SLB leak rate per voltage interval is evaluated as the number of indications-in the interval times the numerical average leak rate of Figure 7-16 evaluated at the mid-point of'the voltage interval. The total SLB leak rato is then obtained as the sum of leak rates per interval for all intervals above-the voltage threshold for leakage.
Table 1 and Figure i show the total SLB leak rate as a function of the leakag9. threshold voltage between 1.0 and 2.0 volts.
For the recommended.
leakage threshold of 2.0 volts, the Table 1 leak i *te of 0.009 gpm is essenti lly the same as the deterministic analysis of Table 10-5 of WCAP-13494.
Even with a voltage threshold assumed to be as low as 1.0 volt, the projected SLB leak is only 0.049 gpm, s---2
$e-
..c.,
These results support the WCAP-13494 results chowing stb leak rates well below the 1.0 gpm allowable limit.
f_olpatHRrt of Bobbin hlign_3e_ tween Repfg1_ln_Syections for about 123 intersections, tobbin voltage data were collt.cted to compare single analyst voltage calls to the voltage calls resulting from the analyst resolution process.
This analysis comparison was performed for voltage calls made from the same data tape (single inspection).
This evaluation is documented in Section 5.8.2 of WCAP-13494.
These data were collected for indications which also had a econd im pection. The second inspection was generally performed to verify the location of the
)
indication and often was done with a smaller probe (0.590") compared to the original inspection (0.610").
For 26 of the intersections, hawever, the probe diameters were the same for both inspections. These 26 indications can be used to compare the voltage differences between the resolution pr:: css and a single analyst for the same data tape (same probing or inspection) to the differer. es between the resolution process on one tape and a singie analyst from another tape (second probing or inspection).
Table 2 proviaes the data for the 26 TSP intersections having two inspections with the samo. probe diameter.
C:lumns 3 and 4 in the Table are the single analyst and resolution process voltages as obtained from one tape.
Column 5 is the sin'ile analyst voltage call from the second tape or inspection.
The resolution process was not usually appliad to-the repeat inspection tape. The last 2 columns prcvide the difference of the sig s analyst calls f rom the resolved voltage calls for both data from the same tape (Column 4-Column 3) and from the two different tapes (Column 4 - Column 5).
In general, the voltage differences for the same tape show about the same differe"ces as obtained between taprs.
For 5
example,18 voltage differences are <0.1 volt for the analysis from the same tape compared to 16 for analysis (ifferences between the +wo taper.
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Overall, the data of Table 2 show that voltage differences obtained between separate inspections of the same irdication are of the same magnitude as voltage differences between separate af.11yses of the same data.
As shown in figure 5-10 of WCAP-13494, the voltage differences between analysts are <20% for voltage indelations above about 0.8 volts.
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9 Tabic 1 CATAWBA UNIT 1 E00-7 SLB LEAK RATE - REFERENCE CASE SENSITIVITY TO SLB 1.EAKAGE THRE$ii3LD THRESH 01.0 1.EAK RATE VOLTAGE (GPM) 1.00 0.049 1.05 0.045 1.10 0.041 1.15 0.037 1.20 0.034 1.25 0.031 1.30 0.028 1.35 0.025 1.40 0.023 1,43 0.021 1.50 0.019
~
1,F' O.017 1.60 0.016 1.65 0.015 1.70 0.014 1.75 0.012 1.80 0,011 2.00 0.009 t-
TABLE 2 Catawba-1 Comparison of Bobbin voltages Between Analyses of Same Data and Between Repeat Inspections (Common Probe Olan:eter)
Volts Volt 51_SAmg.lapa
?nd 1Ap3 Differgnces ciagle Single Same Second Re}_o].y.es Analyst Jape Taoe TS2 Analyst S
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R2C83 6
0.26 0.19 0.13
-0.07 0.06 R36C93 2
2.00 2.00 1.92 0,0 0.08 3
0.34 0.38 0.se 0.04 0.02 R9C91 2
3.51 3.51 3.69 0.0
-0.18 3
1.13 1.12 1.08
-0.01 0.04 4
0.41 0.42 0.39 0.01 0.03 RiEC20 3
0.42 0.37 0.38
-0.05
-0.01 5
0.53 0.77 0.76 0.24 0.01 6
0.26 0.22-0.18 0.04 0.04 R5C58 2
0.44 0.42 0.50
-0.02
-0.08 I
R47.17 2
0.33 0.24 0.50
-0.09
~0.26 R6C9 2
0.45 0.45 0.43 0.0 0.02 3
1.07 1.07 1.10 0.0
-0.03 R12C76' 2
0.10 0.29 0.13 0.19-0.-16 R44C40 4
0.18 0.20 0.16 0.02 0.04 R12086 2
0.38 0.39 0.27 0.01 0.12 3
0.25 0.54 0.36 0.29 0.18 5
0.23 0.62 0.18 0.39 0.44 R23C77 2
0.15 0.18 0.04 0.03-0.14 3
0.35 0.77 0.24 0.42 0.53 R31C89 2
1.38 1.57 1.35 0.19 0.22 4
0.24 0.44 0.38 0.20 0.06 R4C104 2
0.44 0.49 0.29 0.05 0.20 3
0,51 0.54 0.52 0.03 0.02 4
0.80 0.92 0.83 0.lc 0.09 RSC68 2
0.29 0.23 0.18
-0.06 0.05
g.
FIGURE 1 CATAWBA UNIT 1 EOC-7 SLB LEAK RATE SENSITIVITY 10 SLB :.EAKAGE THRESHOLD O.05 7
y 0.04-
- - - - ~ ~ ~ ~ ~ - - -
D uJ Ft L
e 0.03- - - ' ~ ~ " - ~ ~ ~ ~
- - - - - - - ~ ~ - - - - - - ~ ~ - - - ~ ~ ~ ~ ~ ~ -
\\
b l
k U
0.02-
- - - - - - - - ~ ~ ~ - - - - - ~ ~ - - - - - -
P gN
~~~~~
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g
.t CC O.01- ~ ~ - - ~ ~ ~ ~ ~ ~ ~ - -
- - - ~ ~ ~ ~ ~ - ~ ~ ~ - ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
- ~ ~ "
]
0-i
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i 1
1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2
SLB LEAKAG5 THRESHOLD, VOLTS 3
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