ML20113B095
| ML20113B095 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 06/30/1996 |
| From: | WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| To: | |
| Shared Package | |
| ML20113B091 | List: |
| References | |
| SG-96-06-006, SG-96-06-006-R01, SG-96-6-6, SG-96-6-6-R1, NUDOCS 9606260172 | |
| Download: ML20113B095 (21) | |
Text
_ -.. _ _
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SG 96 06 006 Revision 1 Byron Unit 1 Interim Plugging Criteria Return to Power Report June 1996 i
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Westinghouse Electric Corporation Nuclear Services Division Madison, PA 15663 9606260172 960619 PDR ADOCK 05000454 G
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Table of Contents i
1.0 Introduction l
2.0 Summary and Conclusions 3.0 EOC-7B Inspection Results and Voltage Growth Rates 3.1 EOC-7B Inspection Results 3.2 Voltage Growth Rates 3.3 NDE Uncertainties l
4.0 Data Base Applied for IPC Correlations 5.0 SLB Analysis Methods 6.0 SLB Leak Rate and Tube Burst Probability for EOC-7B l
7.0 References 4
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Byron Unit 1 Interim Plugging Criteria Return to Power Report 1.0 Introdudion This report provides the Byron Unit 1 steam generator tube Eddy Current (EC) inspection results at the end of Cycle 7B* together with Steam Line Break (SLB) leak rate and tube burst probability analysis results calculated using the measured voltage data, to implement a 3.0 volt Interim Plugging Criteria (IPC). SLB leak rates and tube burst probabilities were calculated considering the locked tube support plate (TSP) condition.
The results based on the actual measured EOC-7B voltage distributions are compared with those based on projected indication distributions using the EOC-7A data. The methodology used in these evaluations is in accordance with previously submitted Westinghouse reports (References 7.1 and 7.2). Projections of EC bobbin voltage distributions, and leak rate and burst probability analyses based on the 3.0 volt repair criteria for the upcoming Cycle 8 operation will be presented in the 90 day report.
2.0 Summary and Conclusions SLB leak rate and tube burst probability analyses were performed for all four steam generators (SG) based on their actual measured EOC-7B voltage distributions and the results compared with the projections performed during the last outage. The results based on the actual voltage distributions for all SGs except SG B are below those predicted using the EOC 7A EC data and a constant probability of detection (POD) value of 0.6. The SG-B leak rate calculated using the actual measured voltages is slightly (about 10 percent) higher than the projections using a POD value of 0.6.
Nevertheless, SLB leak rates and burst probabilities based on the actual EOC-7B voltage distributions for all four SGs are at least two orders of magnitude below their allowable limits. In general, the results based on the actual voltages are closer to the projections which used the EPRI POD distribution, aed those based on a constant POD value of 0.6 are conservative (i.e., higher than the actuals).
. For the actual EOC-7B bobbin voltage distributions, the largest SLB leak rate is calculated for SG B and its magnitude is 0.274 gpm. The corresponding burst probability is below 4x10 8 (only cold leg indications contribute to burst for a locked TSP condition). These values are much lower than the allowable Cycle 7B SLB leakage limit of 35.7 gpm and the NRC reporting guideline of 10' for the conditional SMee this is the second of two inspections conducted during Cycle 7, for clarity, the cycle completed before the mid-cycle inspection is referred to as Cycle 7A and the cycle just completed as Cycle 7B.
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tube burst probability. Thus, the results are well within the allowable limits, and the EOC 8 projections, to be reported in the 90 day report, can also be expected to meet the requirements. However, the SLB leak rate projections for EOC 8 will be higher than found for the actuals due to the GL 95 05 requirement to use a constant POD value of 0.6.
A total of 5719 indications were found in the EOC-7B inspection of which 291 were inspected with a Rotating Pancake Coil (RPC) probe (including a minimum of 20 %
of hot leg indications between 1 and 3 volts and all hot leg indications above 3 volts),
and 220 were confirmed as flaws. The RPC confirmed indications included 204 above 1.0 volt. The largest number of bobbin indications, 2040 indications, were found in SG C, of which 369 were above 1.0 volt,115 of those were inspected by RPC and 84 were confirmed as flaws. Seven indications were found above 3 volts in all SGs combined, of which five were found in SG B, and all of them were confirmed by RPC.
Ten RPC signals were classified as volumetric; they all had patterns consistent with cellular patches and, hence, IPC is applicable to the TSP intersections where they were found.
An ID initiated, axial indication was reported in'a dent (expected to be a mechanical ding) at the edge of the sixth TSP on the cold leg side of tube R1-C74 in SG A. The indication starts at the top of the TSP and extends upwards 0.21" outside the TSP.
Its RPC voltage is 1.17 volts (115 mil pancake coil) and the bobbin voltage of the dent is 15.77 volts. There is also another dent of magnitude 7.13 volts at that intersection located entirely within TSP. No other ID indications at dented TSP intersections or circumferential indications at the TSP intersections or indications extending outside the TSP were found in this inspection.
3.0 EOC-7B Inspection Results and Voltage Growth Rates 3.1 EOC-7B Inspection Results In accordance with the IPC guidance provided by the NRC Generic Letter 95 05, the end of Cycle 7B inspection of the Byron Unit 1 steam generators (SG) consisted of a complete,100% EC bobbin probe fulllength examination of the tube bundles in all four SGs. A 0.610 inch diameter probe was used for all hot and cold leg TSPs where IPC was applied. Subsequently, RPC examination was performed for a minimum of 20 percent of the hot leg indications with an amplitude between 1 and 3 volts, all hot leg indications with an amplitude 3 volts and above, and all cold leg indications.
Seven hot leg indications had a bobbin voltage above 3 volts; they were all confirmed as flaws and plugged. The only cold leg indication with a bobbin voltage above 1 volt was not confirmed by RPC and, hence, it was not repaired.
In addition, an augmented RPC inspection was performed consistent with the NRC
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6 requirements. All dented intersections with a bobbin voltage greater than 5 volts and a minimum of 20 percent of the dented intersections with a bobbin voltage between 2.5 and 5 volts were inspected with RPC.
Only one flaw was reported in the augmented inspection: an ID initiated, axial indication was found in a dent at the edge of sixth TSP en the cold leg side of tube R1-C74 in SG-A. The indication starts at the top of the TSP and extends upwards 0.21 inch outside the TSP. Its RPC voltage is 1.17 volts (115 mil pancake coil) and the bobbin voltage of the dent is 15.77 volts. There is also another dent of magnitude 7.13 volts at that intersection located entirely within the TSP.
Apart from this ID indication, there was no other unexpected eddy current results in this inspection. There were no RPC circumferential indications at the TSPr>, no indications (other than R1 014) extending outside the TSPs, and no RPC indications with potential ID phase angles (except for RI C14 in SG A). Also, no mixed residual artifact signals or signalinterference from 1
copper deposits were found during this inspection.
A summary of EC indications for all four steam generators is shown on Table 1, which tabulates the number of field bobbin indications, the number of those indications that were RPC inspected, the number of RPC confirmed indications, and the number ofindications removed from service due to tube repairs. The indications that remain active for Cycle 8 operation is the difference between the observed and the ones removed from service. The steam generator repair list has not yet been finalized pending completion of the sleeving operation. The numbers shown for indications removed from service and indications returned to service are based on a preliminary repair list, and as such, they may be revised.
Overall, the combined data for all four steam generators of Byron Unit 1 shows that:
Out of a total of 5719 TSP indications identified during the inspection, a total of 291 were RPC inspected.
Of the 291 RPC inspected, a total of 220 were RPC confirmed.
Based on the preliminary repair list, it is expected that at least 269 indications would be removed from service. Only 7 ODSCC indications require repair based on exceeding 3 volts. No cold leg TSP indications require repair.
Consistent with the 3 volt IPC, hot leg indications with bobbin amplitude less than or equal 3.0 volts and cold leg indications less than or equal to 1 volt are not considered for removal from service, regardless of RPC data.
A review of Table 1 indicates that more indications (a quantity of 1971, with 348 indications above 1.0 volt) would be returned to service in SG-C than the other SGs, per preliminary repair list, thereby it potentially will be the limiting SG at EOC-8.
However, it is also noted that SG B had the largest indication (4.5 volts) found in the
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EOC 7B inspection. Figure 1 shows the actual bobbin voltage distribution from the EOC 7B EC inspection Figure 2 shows the population distribution of those EOC 7B indications removed from service due to tube repairs; Figure 3 shows the indications which could be returned to service for Cycle 8, per preliminary tube repair list. Of the 269 indications to be removed from service, only 7 indications exceeding 3 volts and 19 indications located in the wedge region (where IPC does not apply) are repaired due to ODSCC at TSPs. The rest of the indications are in tubes plugged for degradation mechanisms other than ODSCC at TSPs.
3.2 Voltage Growth Rates Table 2 shows the cumulative probability distribution function for growth rate of each Byron Unit I steam generator during the last two operating periods (Cycles 7A and 7B). The growth rates are presented on an EFPY basis to account for the difference in the length of the two operating periods. Figure 4 provides a comparison of the composite voltage growth from all four steam generators for the last three operating periods. For Cycle 7B operation, SG-B has a slightly larger average voltage growth among the four steam generators, and it also has the indication with the largest voltage growth.
The composite growth rates from all SGs for Cycle 7B shown in Figure 4 appear to be higher than those for the two prior operating periods. However, since Cycle 7B was a very short cycle (only 87.8 EFPDs), the differences between the current and last inspection bobbin voltages were multiplied by a factor of about 4 to convert them to the growth rate / EFPY values shown in Table 2 and Figure 4.
Some of the differences noted in the growth rates for the various cycles is attributable to the uncertainties associated with the measured bobbin voltages, which gets exaggerated when the voltage differences are multiplied by a factor as high as 4 to convert the growth rates to an EFPY basis. Thus, some of the larger EFPY growtn values for Cycle 7B in Table 2 and Figure 4, both positive and negative values, are likely to be overestimated.
3.3 NDE Uncertainties The NDE uncertainties applied for the Cycle 7B voltage distributions in the Monte Carlo analyses for leak rate and burst probability are the same as those described in the Braidwood Unit 1 IPC report of Reference 7.1. The probe wear standard used in the analyses has a standard deviation of 7.0 % about a mean of zero and a cutoff at 15 % for voltage response variability, which is consistent with the alternate probe sTapcNeae96%cyde7B rty
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wear measurement approach used during the EOC-7B inspection. The analyst variability uncertainty has a standard deviation of 10.3% about a mean of zero with no cutoff.
i 4.0 Database Applied for IPC Correlations Consistent with the RAI responses provided in Reference 7.4, IPC correlations based on the up to date database available for 3/4" diameter tubes were applied in the analyses presented in this report. The database is in compliance with the NRC GL 95 05 guidelines for application of leak rate versus voltage correlations and for removal of data outliers in the 3/4 inch tubing burst and leak rate correlations.
5.0 SLB Analysis Methods Monte Carlo analyses are used to calculate the SLB leak rates and tube burst probabilities for actual voltage distributions. The methodology used complies with the Byron Unit 1 SER and is described in Reference 7.1, and also in the Westinghouse generic methods report of Reference 7.2.
Monte Carlo analyses for leak rates and tube burst probabilities for the actual distributions include NDE uncertainties.
Based on the 3/4" diameter tubing database, the NRC requirement that the p value obtained from the regression analysis be less than or equal to 5% to apply the SLB leak rate versus voltage correlation is satisfied and the correlation is applied for the leak rate analyses of this report.
SLB leak rates and tube burst probabilities are calculated considering the locked TSP condition. With TSPs locked (by tube expansion), indications in the hot leg side are restrained from bursting so the burst probability calculations are based only on indications found on the cold side. Since only a small fraction of the indication population is on the cold leg side, the burst probabilities are expected to be substantially smaller th
. hose estimated with the usual IPC/APC methodology (which includes the entir adication population). Leak rate analyses for the hot leg indications include indications restrained from burst (IRBs) based on a 6.0 gpm leak rate for IRBs. Leak rates for cold leg indications are calculated using the methods of GL 95-05 and Reference 7.2.
Leak rates and PoB calculated using the actual voltage distributions are compared with the corresponding prior projections for EOC-7B.
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6.0 SLB Leak Rate and Tube Burst Probability for EOC-7B Using the methodology described above, analyses were performed to calculate EOC-7B SLB leak rate and tube burst probabilities for the actual bobbin voltage distribution presented in Table 1. The results are summarized on Table 3.
The corresponding results from the calculations performed during the last outage to project EOC 7B leak rates and tube burst probabilities are shown in Table 4. A comparison of the EOC 7B actuals with the corresponding predictions indicates the following:
a)
SG-B was projected to be the limiting steam generator for EOC 7B based on EOC-7A EC data and SG B was also determined to have the highest SLB leak rate based on actual EC bobbin measurements for EOC-7B. The leak rate based on the actual voltages is slightly (about 10 percent) higher than the projections with a POD of 0.6 and only 0.11 gpm higher than calculated with the EPRI POD. However, the calculated SG-B leak rate (0.274 gpm) is still two orders of magnitude below the acceptance limit (35.7 gpm).
b)
As evident from Figures 5 and 6, the projected EOC-7B voltage distributions are conservative in comparison to the actual measured voltage distributions over most of the voltage range. Except SG-B, the actual peak voltages for all SGs are well below their projected values. SG B had one indication with a voltage greater than the predicted peak voltage (4.5 actual vs 4.0 predicted).
Without this indication the SLB leak rate based on the actual voltages would be below that projected.
c)
The PoB values from the projections as well as the actuals are much lower than the allowable limiting value of 10'. The PoB values are very low because of prevention of hot side indication from bursting due to TSP locking by tube expansion.
d)
Except for the small difference in the SG-B leak rate, the results based on the actual measured voltage distributions are closer to the projections based on the EPRI POD distribution than the projections using the NRC mandated POD value of 0.6.
e)
The leak rate and PoB predictions for all four SG's based on EOC-7B bobbin measurements are two orders of magnitude below the allowable limits.
In summary, the limiting SLB leak rate (0.274 gpm) and tube burst probability 4
(below 4x10 ) calculated using the actual measured EOC-7B bobbin voltage a \\ ape \\cae96%cyde78 rto
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distributions are wellbelow the corresponding limits (35.7 gpm and 10 2, respectively).
The SG B leak rate based on the actual voltages is slightly (about 10 percent) higher than projected using a constant POD value of 0.6 and it is due to one indication with a voltage 0.5 volts above the peak voltage in the projections. The results meet the IPC requirement for continued operation. Predictions for EOC 8 will be presented in the 90 day report, and it can also be expected to be well below allowable leak and burst limits.
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1 7.0 References 7.1 WCAP 14046, Rev.1, "Braidwood Unit 1 Technical Support for Cycle 5 Steam Generator Interim Plugging Criteria", Westinghouse Nuclear Service Division.
7.2 WCAP-14277, "SLB Leak Rate and Tube Burst Probability Analysis Methods for ODSCC at TSP Intersections", Westinghouse Nuclear Services Division, Jan.1995.
1 7.3 NRC Generic Letter 95 05, " Voltage Based Repair Criteria for the Repair of Westinghouse Steam Generator Tubes Affected by Outside Diameter Stress Corrosion Cracking", USNRC Office of Nuclear Reactor Regulation, August 3, 1995.
7.4 Letter from Commonwealth Edison Co. to NRC, " Responses to RAI for Questions 58 to 65," dated September 19,1995.
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7.5 WCAP-14273, " Technical Support for Alternate Plugging Criteria with Tube Expansion at the Support Plate Intersections for Braidwood-1 and Byron-1 Model D Steam Generators," Westinghouse Nuclear Service Divi.aion, February 1995.
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Table 2 Byron Unit-1 April 1994 Signal Growth Statistics For Cycle 78 on an EFPY Basis Seeses Generseer A Semen Generseer B Steen Generator C Steam Genersoor D Canelaeve Deles Cycle 7A Cycle 75 Cycle 7A Cycle 75 Cycle 7A Cycle 75 Cycle 7A Cycle 75 Cycle 7A Cycle 7B CPDF CPDF CPDF CPDF CPDF CPDF CPDF CPDF CPDF CPDF
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40 0.092 0.0012 50 0.062 0
70 0.102 0.0011 35 0.096 0.0006 195 0.0t7
-0.2 0.002 100 0.190 0.00$0 98 0.119 0.003 120 0.162 0.0023 75 0.189 0.0034 393 0.157 0.1 0 018 60 0.249 0.0206 84 0.167 0.021 107 0.215 0.0158 68 0.274 0.01 %
319 0.214 0
0.081 145 0.391 0.1149 16l 0.259 0.125 188 0307 0.0948 90 0.386 0.1085 582 0.319 0.1 0305 95 0.484 0.3702 124 0.330 0 381 123 0368 0.3262 63 0.464 0.3536 405 0.391 0.2 0.501 100 0.582 0.5743 128 0.403 0.563 153 0.444 0.5327 67 0.547 0.5499 447 0.471 0.3 06%
90 0.671 0.7291 207 0.522 0.716 185 0.535 0.6919 84 0.652 0.7123 566 0.572 0.4 0.831 56 0.725 0.8227 110 0.585 0.831 ll7 0.593 0.7901 54 0.719 0.8210 337 0.633 0.5 0 897 61 0.785 0.8752 126 0.657 0.884 130 0.657 0.8533 53 0.785 0.8781 370 0.699 0.6 0 938 37 0.822 0.9182 79 0.702 0.924 87 0.700 0.9120 27 0.818 0.7227 230 0.740 0.7 0 961 36 0.857 0.9438 65 0.739 0 951 70 0.735 0.9402 21 0.845 0.9487 192 0.774 0.4 0 975 33 0.889 0.9563 88 0.790 0.%8 95 0.782 0.9582 39 0.893 0 9638 255 0.820 0.9 0 988 26 0.915 0.9682 34 0.809 0.981 50 0.807 0.9673 16 0.913 0.9756 126 0.842 1
0.992 14 0.932 0.9775 56 0.841 0.986 61 0.837 0.9786 19 0.937 0.9830 154 0.870 1.1 0.092 14 0.946 0 9850 32 0.860 0.990 45 0.859 0.9842 8
0.947 0.9878 99 0.888 1.2 0 996 7
0.953 0.9875 25 0.874 0.994 32 0.875 0.9876 9
0.958 0.9910 73 0.901 13 0.997 7
0.960 0.9931 40 0.897 0.997 48 0.899 0.9932 7
0.966 0.9950 102 0.919 t.4 0.998 11 0.971 0.9950 19 0.908 0.997 26 0.912 0.9944 4
0.971 0.9962 60 0.930 1.5 0.999 7
0.977 0.9969 19 0.919 0.998 23 0.923 0.9955 7
0.980 0.9974 56 0.940 l.6 0.999 I
0.978 0.9969 17 0.928 0.999 18 0.932 0.9955 2
0.983 0.9976 38 0.947 t.7 1.000 3
0.981 0.9975 13 0.936 0.999 17 0.940 0.9955
'4 0.988 0.9980 37 0.953 l.8 2
0.983 0.9988 16 0.945 0.999 20 0.950 0.9977 4
0.993 0.9990 42 0.961 l.9 4
0.987 0 9988 7
0.949 0 999 I5 0.957 0.9977 1
0.994 0.9990 27 0.965 2
2 0.989 0.9988 13 0.956 0.999 10 0.962 09989 0
0.994 0.9992 25 0.970 2.1 1
0.990 0.9994 10 0.%2 1.000 7
0.966 0.9989 0
0.994 0.9996 18 0.973 2.2 2
0.992 0 9994 7
0.966 Il 0.971 1.000 2
0.996 0.9998 22 0.977 2.3 3
0.995 0 9994 9
0.971 13 0.978 0
0.996 0.9998 25 0.982 2.4 2
0.997 0.9994 4
0.974 7
0.981 0
0.996 0.9998 13 0.944 2.5 0
0.997 1.000 9
0.979 4
0.983 0
0.996 1.000 13 0.986 2.6 0
0.997 4
0.981 3
0.985 0
0.996 7
0.987 2.7 0
0.997 1
0.982 l
0.985 1
0.998 3
0.988 Y
l 0.998 6
0.985 4
0.987 1
0.999 12 0.990 2.9 0
0.998 4
0.987 1
0 988 0
0.999 5
0.991 3
0 0.998 5
0.990 3
0.990 0
0.999 to 0.993 31 0
0.998 2
0.991 1
0.991 0
0.999 3
0 993 3.2 0
0.998 3
0.993 3
0.992 0
0.999 6
0.994 3.3 0
0.998 1
0.994 2
0.993 1
1.000 4
0.995 34 0
0.998 0
0.994 2
0.994 2
0.996 3.5 0
0.998 0
0.994 2
0.995 2
0.996 3.6 0
0.998 2
0.995 2
0.996 4
0.997 3.8 0
0.998 2
0.996 0
C 996 2
0.997 4
0 0.998 0
0.996 2
0.997 2
0.997 4.5 1
0.999 3
0.998 1
0.998 5
0.998 5
0 0.999 1
0.998 1
0.998 2
0.999 5.5 t
1.000 0
0.998 1
0 999 2
0.999 6.5 1
0.999 2
0.9995 3
0.999 7
1 0.999 0
0.9995 1
1.000 7.5 0
0.999 1
1.000
~ '
8 I
l.000 Total 1020 1746 l2023 804 5590 1.000
.om - -..ma
,n,
Table 3 Byron Unit 1 1995 EOC-7B Outage Summary of Calculations dTube Leak Rate and Burst Probability Based on Adual Bobbin Voltage Burst Probability SLB Steam Number Max.
Leak Generator POD of Volts ("
Rate 1 Tube 2 Tubes India-gym mtions EOC - 7B ACTUAIS Hot Side 1
1014 3.9 Negligible"' Negligible'*)
0.064 A
Cold side 1
9 1.1
< 4 x 10' '
< 4 x 10- *
< 0.001 1023 3.9
< 4 x 10' '
< 4 x 10' '
O.064 Combined Hot Side 1
1779 4.9 Negligible"'
Negligible"'
O.274 B
Cold Side 1
12 1.2
< 4 x 10- *
< 4 x 10' '
< 0.001 Combined 1791 3.5
< 4 x 10' '
< 4 x 10' '
O.274 Hot Side 1
2035 3.5 Negligible"'
Negligible"'
O.132 C
Cold Side 1
5 1.6
< 4 x 10' '
< 4 x 10' '
< 0.001 Combined 2040 3.2
< 4 x 10' '
< 4 x 10' '
O.132 Hot Side 1
859 3.5 Negligible"'
Negligible")
0.041 D
Cold Side 1
6 1.0
< 4 x10' '
< 4 x 10' '
< 0.001 865 3.5
< 4 x 10' '
< 4 x 10' '
O.041 Combined douta 1 Voltages include NDE uncertainties from Monte Carlo analyses and exceed measured voltages.
2 Below 10(Refereace 7 5)
.%,evu u vyci.7s.n, 12-
Table 4 Byron Unit-1 Summary of Projected Tube Leak Rate and Burst Probability for EOC-7B Burst Probability SLB Steam Na of Max.
Leak Generator POD Indio.
Volts"'
1 Tube 2 Tubes Rate ations")
gpm EOC - 7B PROJECTIONS BASED ON EOC-7A DATA ")
Hot Side 0.6 1436 3.9 Negligible (')
Negligible (3) 0.11 A
4 4
4 Cold Side 0.6 5
0.8
< 4.0x10
< 4.0x10 1x10 4
4 Total 0.6 1441
< 4.0x10
< 4.0x10 0.11 Hot Side EPRI 1321 3.6 Negligible (2)
Negligible (3) 0.07 A
4 4
Cold Side EPRI 5
0.8
< 4.0x10
< 4.0x10 1x104 4
4 Total EPRI 1326
< 4.0x10
< 4.0x10 0.07 Hot Side 0.6 2513 4.0 Negligible (2)
Negligible ( )
0.25 B
4 4
4 Cold Side 0.6 4
1.5
< 4.0x10
< 4.0x10 1x10 4
4 Total 0.6 2517
< 4.0x10
< 4.0x10 0.25 Hot Side EPRI 2285 3.9 Negligible ( )
Negligible (')
0.16 B
4 4
4 Cold Side EPRI 3
1.4
< 4.0x10
< 4.0x10 1x10 4
4 Total EPRI 2288
< 4.0x10
< 4.0x10 0.16 Hot Side 0.6 2606 3.9 Negligible (3)
Negligible (')
0.21 C
4 4
Cold Side 0.6 2
~1
< 4.0x10
< 4.0x10 1x 10-'
4 4
Total 0.6 2608
< 4.0x10
< 4.0x10 0.21 Hot Side EPRI 2360 3.8 Negligible (3)
Negligible (8) 0.14 C
4 4
Cold Side EPRI 2
~1
< 4.0x10
< 4.0x10 1x 10
4 4
Total EPRI 2362
< 4.0x10
< 4.0x10 0.14 Hot Side 0.6 1245 3.9 Negligible (')
Negligible (3) 0.14 D
4 4
Cold Side 0.6 1
~0.5
< 4.0x10
< 4.0x10 1x10*
4 4
Total 0.6 1246
< 4.0x10
< 4.0x10 0.14 Hot Side EPRI 1186 3.7 Negligible (2)
Negligible ( )
0.01 Cold Side EPRI 2
0.5
< 4.0x10
< 4.0x10 1x 10-'
4 4
4 Total EPRI 1188
< 4.0x10
< 4.0x10 0.01 Notes
.(1) Number ofindications adjusted for POD.
(2) Voltages include NDE uncertainties from Monte Carlo analyses and exceed measured voltages.
(3) Below 10(Reference 7-5)
(4) Based on a projected cycle 7B length of 116.1 EFPD (Actual Cycle 7B duration is 87.7 EFPD) s \\apcWe96Wcle7B.rt, 13-
i1l l
ll
- 9n
- Mm A
B C
D G
G G
G S
S S
S
- mm E
O G
E B
- hn 7
e l
y L
c C
- 9n g
n i
r J
D
- 9n u
A ec i
v G
e
- 9n r
e gS
^
a n t i
- d u
s Oe
- S.-
e b
g d
a 6 u t
99 T o
l r pB
=: NV 1
r 1
l o
if n
e r ib b
u 4*
gA7 o
14 F1 C 9B i
O t
iE nt
=
U a s
n
,9-n o
r o i
yt B u b
,~-
ir ts i
D W
e g
,S.o a
t loV n
No i
bbo B
- 9o
, 9o
]
o 1
3_
ig F
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
C 0
8 6
4 2
0 8
6 4
2 0
8 6
4 2
f 1
1 1
1 1
Y 3
2 2
2 2
2 F
R
,E=8jCo h N
B OB i
Figure 2 Byron Unit-1 April 1996 Outage Bobbin Voltage Distribution for Tubes Plugged After Cycle 7B Service 20 l
i ESG-A l
15 -
l OSG-B EO t
j sSG-C l
- s
'O' ESG-D e
.c E
sZ 5-0 c!
v.
'o ci et M
9 v.
et M
9
~
e4 e4 e4 m
m o
o o
o Bobbin Voltage ;
BOBNRPC.XLSFig. 3-2 l
Figure 3 Byron Unit -1 April 1996 Outage Bobbin Voltage Distributions for Tubes Returned to Service for Cycle 8 300
]
i 280 -
l t
260 -
240 -
l ESG-A 220 -
200 -
OSG-B f
oj 180 -
u j
- E 160 -
B SG -C C
o 140 -
.j 120-ESG-D l
=
100 -
Z 80 -
l l
l 60 -
l l
40 -
l 20 -
- = l':I ':I
- ^:d:
- ':";-lR: -:-l 0
i t
1 0.1 0.2030.40.50.60.70.80.9 1 1.1 1.2 13 1.4 1.5 1.6 1.7 1.8 1.9 2 2.12.2232.42.52.62.72.8 i
Bobbin Voltage
! l noemuc.nsn.u s
Figure 4 Comparison of Byron-1 Growth Rates Cumulative Probability Distributions on EFPY Basis Composite of All Four Steam Generators 1.0 go0u000000
-x-x-x-i-1-a-a-x-x s s-x-x-x-x - x + x x-x-x-x+--
E 0.9-
.C.
/*
Y_:'
0.8 -
I4 a
f 0.7 -
D*
oa g-g f
- - + - - Cycle 6 I
0.6 -
..t a.
5
^
l j 0.5 ~
- o-- Cycle 7A 5
.E 0.4 3
3
-x-Cycle 7B E
0.3 -
a P
U t
0.2 -
_I O.1-
- 1 0.0 n-x-x-x-x-mee-Y-Y-
- ; yi$g;ya3 3 5 S 5 5 2 A 3 2 3 2 0 0 2 2 2
Voltage Growth mo-m ae
Figure 5 Byron Unit-1 Comparison of Predicted and Actual Bobbin Voltage Distributions for Cycle 7B Combined Data for Hot and Cold Leg Indications Steam Generator A 250 200 0 Actual E
$50 s Prediction, POD =0.8 b
1 100 2
50 I 3 rl r14.m_.
0 Bobbin Voltage Steam Generator B seo 320 280 0 Actual 240 m Prodlction. POD =0.8 I
160 2
120 80 40 fr
_ _E,a rn 2. - rt __. _ - - -
0 a
Bobbin Voltage a:Napevaeosvycle18. sty
- 18
- socaw as w enes n rr am
Figure 6 Byron Unit-1 Comparison of Predicted and Actual Bobbin Voltage Distributions for Cycle 7B Combined Data for Hot and Cold Leg Indications Steam Generator C mo 3so soo OActual 250 a W pod =e.e 2co 150 10o 50 0
' * " ^ - ~ ^ ^ ' - ^ ^ ^ - - - -
sown vomme.
i st
- o..rator n
~
200 P
100 om
~
mer.monon,poo e.e 1
so
- e. --.-
0 N#'"--^-----
I-sown von.e.
. w w w.rs.
19
-......