ML20135E531
| ML20135E531 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 11/30/1995 |
| From: | NORTH ATLANTIC ENERGY SERVICE CORP. (NAESCO) |
| To: | |
| Shared Package | |
| ML20135E522 | List: |
| References | |
| NUDOCS 9612110332 | |
| Download: ML20135E531 (28) | |
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J NORTH ATLANTIC ENERGY SERVICE CORPORATION SEABROOK STATION l
l STEAM GENERATORS A AND D INSERVICE INSPECTION i NOVEMBER 1995 1
t 9612110332 961127 PDR ADOCK 05000443 G PDR
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l TABLE OF CONTENTS :
i Section Page i
1.0 Introduction 2 l l
2.0 Discussion 3 ;
3.0 Conclusion 9 f
4.0 References 10 l Tables No.1 through 10 11 -20 .
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Attachment 1 21 Attachment 2 24 I
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1.0 Introduction !
An examination of the Seabrook steam generator (SG) tubes was performed ,
on steam generators A and D during Refueling Outage No. 4 (RFO 4). The examination began on November 23,1995 and was completed on November >
27,1995. The examination was performed by Westinghouse Nuclear Service {
Division, with oversight by Northeast Utilities (NU) Nuclear Water Chemistry ,
(NWC). This was accomplished in accordance with Seabrook Station j l
Technic 6 Specification 4.4.5. This report presents results of the inspection i pursuani to Technical Specification 4.4.5.5.b. The following results are l presented: i
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. Tne number and extent of tubes inspected. !
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. The location and percent of wall-thickness penetration for each indication j of an impelfection. !
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. Identification of tubes plugged.
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Seabrook Station is a Westinghouse four-loop pressurized water reactor with Model F steam generators. The generators are U-bend heat exchangers with j l tube bundles fabricated using thermally treated inconel 600 tubing. Each l' tube is identified by a row and column number; there are 59 rows and 122 i columns in each steam generator for a total of 5,626 tubes. Nominal tube l OD is 0.688" with a 0.040" nominal wall. l The Technical Specifications require a tube to be plugged when tube wall-loss equals or exceeds 40% of nominal wall. A total of 12 tubes (8 in SG A and 4 in SG D) were plugged as a result of eddy current inspection. One cold leg Inconel 600 mechanical plug was removed and replaced with an inconel l 690 plug, pursuant to NRC Bulletin No. 89-01 and Westinghouse WCAP-12244.
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2.0 Discussion l
A full length bobbin coil eddy current examination was performed on a total of l 4,867 tubes in S/G A and S/G D. The inspection practice at Seabrook has been to inspect two of the four steam generators on a rotating basis each i refueling outage. The inspection workscope represented approximately 43 percent of the tubes in each of the steam generators examined.
The inspection was performed in four SG channel heads in parallel using D4 probe pushers, ROSA manipulators and bobbin coil probes manufactured by i Westinghouse. The eddy current examination data was recorded directly onto optical disks and transmitted to Pittsburgh via a T1 phone line. On-line l data analysis was performed in Pittsburgh by two independent analysis ;
teams (Primary and Secondary). The preliminary inspection results were l transmitted back to the Seabrook site via the T1 phone line. The results were compared, reviewed by the lead analyst, and finalized.
Prior to performing data analysis, all data analysts were required to successfully complete a NU developed ECT Data Analyst Training and i Performance Demonstration program. This program was based upon the Millstone 3 / Seabrook Steam Generator Eddy Current Data Analysis Guidelines manual, Reference 1, which is intended to ensure that the most appropriate data analysis practices are used and that the data is analyzed in a consistent manner. Prior to this inspection, a revision to this manual included an update of the rotating probe data analysis guidelines for the newly designed plus-point coil, along with a new section on analysis of Cecco probe data. Over and above the Technical Specification bobbin coil l examination requirements, both Cecco and RPC probes were used to gain an !
increased understanding of the condition of the Seabrook steam generators. !
I Seabrook NDE Program Improvements l
A proactive approach has been applied to the Seabrook steam generator inspection program. New inspection methods are continuously incorporated into the NDE program to address unique conditions which are or may be present in the Seabrook steam generators. The following improvements were introduced into the Seabrook NDE program for the first time during i RFO 4:
. A new tester unit allowed data to be acquired at faster test speeds.
During previous examinations, bobbin coil data was collected at probe ,
speeds of 24 inches per second (ips). The new TECRAD 6700 tester unit, used by Westinghouse, allowed increased data sampling rates. NWC had
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previously qualified bobbin coil test speeds of up to 40 ips based on both laboratory and field comparisons between 24 ips and 40 ips which i showed the data from both test speeds to be identical, Reference 2.
l Based on this qualification program, the Seabrook ANil approved the use of the 40 ips test speed. The faster test speed resulted in an increase in the data acquisition rate, thereby shortening the inspection duration. ,
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e The use of a Cecco-5 probe resulted in a quick, reliable means to inspect :
for the presence of cracking. This probe, which contains 8 transmit- )
i receive coil pairs along with a bobbin coil, is capable of detecting cracks j regardless of their orientation. 1
- . Probe sizes and test speeds were optimized to ensure good quality data was collected and the need to retest due to inner row U-bend restrictions was minimized. The bobbin probe sizes and test speeds used were as l follows:
1 e Rows 3 - 59: 0.560" dia, full length,40 ips e Row 1 - 2 : 0.560" dia, hot leg and cold leg straight length,24 ips
- 0.520" dia, U-bend,24 ips e A rotating plus-point coil was used to examine the U-bend region of selected Row 1 tubes. The plus-point coil design reduced the interfering tube noise typically encountered in this region by standard pancake coils.
l The quality of the plus-point data was excellent and allowed for an accurate assessment of the condition of the inner row U-bends.
l e Measurements of top-of-tubesheet tube deposit heights were made from l the bobbin coil data for all tubes examined. So as not to impact the examination schedule, an automated data analysis program was written to perform this measurement in the background.
Examination Workscope and Results Bobbin Coil Exam Table 1 identifies the initial inspection workscope and tube selection criteria.
Since tube wear at AVB locations represents the only active tube degradation mechanism identified, the bobbin coil sample was selected to include those tubes where AVB wear has or would not likely be expected to occur. All !
tubes in Rows >25, which were not examined in RFO 2, were selected for ,
- examination.
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Table 2 provides a summary of the eddy curren' '.ests actually performed during RFO 4. Full length bobbin coil tests were performed on 2,424 tubes in ,
SG A and 2,443 tubes in SG D. To optimize the inspection schedule, some :
tubes were examined part length from both hot and cold legs to achieve the !
full length test.
l A summary of the RFO 4 steam generator examination results is provided in j l
Table 3. All identified service induced tube flaws >20% thrcughwall was :
caused by wear at the tube /antivibration bar contact points The twelve - i
>20% throughwall flaws not caused by AVB wear, were introduced into the tubing during the steam generator manufacturing process and have not !
l increased in depth since the 1985 baseline eddy current examination. A complete listing of all >20% throughwall flaws identified during the RFO 4 :
steam generator examination is provided in Attachments 1 and 2. I l Abnormal signal indications were also noted at the tube tangent point, where the U-bend meets the straight tube length. Previous reviews of 1985 baseline ECT data for a sample of the tubes with " tangential flag signals" ;
confirmed that the indications were present and had not changed during operation. The indications are believed to be caused by geometry variations ,
l introduced by the bending process. Rotating probe testing, performed during -
i previ ous inspec tions, con firmed the tangent point signals to be non-flaws. .
Nonquantifiable bobbin coil signals were identified at 24 tube locations. - A review of the 1985 baseline data for 21 of these tubes indicated that the signal indications were unchanged. The three tubes, with indications that could not be confirmed on the baseline data, were inspected by the 3-coil ,
rotating probe. No tube degradation was identified.
Top-of-tubesheet tube deposit height measurements were performed for the first time at Seabrook during RFO 4. The measurements were made from the bobbin coil data for all 4,867 tubes examined. Measurements were made ;
following sludge lancing at both hot leg and cold leg top-of-tubesheet !
locations. The measured " deposit" height could represent either a pile of sludge between the tubes or a deposit accumulation on the tubes. The ECT measurement cannot differentiate between these two conditions. However, with fewer than one percent of the tested tubes having measurable deposit heights, it is clear that the above tubesheet area is in a relatively clean "
condition. Those tubes in which deposits were reported were located in the l center of the SG in the lower tube rows, as is typical in most SG designs. ,
j Table 4 provides a summary of the tube deposit height measurements in ;
each of the four SG channel heads which were examined.
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Cecco Probe Exam '
i Prior to the April 1995 Callaway steam generator inspection, the only tube degradation mechanism observed in domestic Model F steam generators had :
been AVD wear. During the Callaway inspection, tubes were identified which !
contained cracks near the hot leg top-of-tubesheet expansion transition I region. The small rotating probe inspection originally planned was increased ;
to 100 percent of the mill annealed tubes (rows > 10) and 10 percent of the l thermally treated tubes (rows 1 through 10) in all four steam generators. The l extent of test was from 3 inches above to 3 inches below the hot leg top-of- >
tubesheet locations. This inspection identified a total of 23 tubes with cracks which included: 10 tubes with circumferential cracks and 15 tubes with axial cracks, including two tubes with both axial and circumferential cracks.
The cause of the Callaway cracking is unknown, although it appears to be ,
associated with both the hot leg expansion region and the hot leg above '
tubesheet sludge pile region. The only tubes which contained cracks were those tubes which were mill annealed. No cracking occurred in any of the thermally treated inconel 600 (1600) tubing.
In response to the Callaway findings and to NRC Generic Letter 95-03, l Reference 3, the scope of the Seabrook steam generator tube inspection i program included a sample of tubes in the region where Callaway had i identified tube cracking. Approximately five hundred tubes each from SG A l and SG D were inspected, from 12 inches above the top of the hot leg j tubesheet to the tube end, using the Cecco-5 probe. The Cecco-5 probe has been qualified for detection of circumferential and axial cracking per Appendix H of the EPRI PWR Steam Generator Examination Guidelines, Reference 4.
The location of the tubes selected for Cecco-5 probe testing corresponded to I the region where all of Callaway's circumferential cracks had been located.
The results of the inspection program confirmed that tube cracking had not occurred at Seabrook in the region where Callaway had observed circumferential cracking.
Unlike Callaway, all tubes in the Seabrook steam generators are thermally treated. The inspection results from the Seabrook steam generators are ,
consistent with industry experience which has shown that no cracking of i thermally treated 1600 tubing has ever occurred in a domestic steam j generator.
I Hatating Plus-Point Exam
! Prior to the Seabrook refueling outage, the NRC requested information regarding circumferential cracking of steam generator tubes at small radius U-bend locations, Reference 5. In responding to the NRC's request, i Seabrook made a commitment to examine the U-bend region of 20 percent of the Row 1 tubes in each of the two steam generators being examined,
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- j Reference 6. NWC selected the ZETEC rotating plus-point probe as the best method of inspecting the Row 1 U-bend region for cracks.
The first time inspection of the Row 1 U-bend region at Seabrook, using the l l
rotating plus-point probe, provided excellent quality data. A total of 50 Row 1 U-bends were examined and were found to be free of degradation. The :
results of this inspection is expected to effectively address NRC concerns <
about circumferential cracking in small radius U-bends of the Seabrook steam generators. ,
Botating 3-Coll Probe Exam l
The rotating 3-coil probe, used in the Seabrook steam generators, consisted I of a plus-point coil, a 0.115" diameter coil and a 0.080" diameter, high frequency coil. This probe has become the industry standard for characterizing steam generator tube degradation. Three of the tubes examined contained non-quantifiable indications (NQl) by the bobbin coil probe. Since the 1985 baseline data did not provide definitive information on whether these indications existed prior to operation, they were examined by the rotating 3-coil probe. The results of the examination confirmed that no tube degradation was present.
Prior to the refueling outage, the NRC requested that Seabrook provide information regarding circumferential cracking of steam generator tubes at dented locations, Reference 5. The Seabrook response to the NRC request, stated that the Seabrook dents were small, were introduced during the steam generator manufacturing process and were not susceptible to cracking after anly four cycles of operation. The small nature of the dents was evidenced
' ' the lack of any probe restrictions in the fulllength bobbin coilinspection cogram. Although Seabrook did not commit to inspecting dented tube scations,24 dented locations examined represented a sample of the largest bobbin dents, based on signal voltage. The results of the examination confirmed that cracking has not occurred at dented locations. Table 2 provides a summary of the rotating 3-coil tests performed.
Technical Specification Evaluation An evaluation of the steam generator results from RFO4 showed both SG A and SG D to be in Category C-2 as defined by Plant Technical Specifications.
l Table 5 provides a summary of the Technical Specification evaluation performed on each steam generator. SG A and SG D were classified as being in Category C-2 as a result of having "one or more tubes, but not more than 1% of the total tubes inspected being defective (>40% TW flaw)". Only those tubes which exhibited >10% TW growth since the last examination l were considered in determining the Technical Specification inspection category. In order to determine the most accurate flaw growth, reanalysis of previous ECT data was performed for all AVB flaws >20% TW identified
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during RFO 4. Seven tubes in SG A and three tubes in SG D met the criteria !
for being considered defective. One of the eight plugged tubes in SG A did !
not exhibit >10% TW growth and was not considered to be defective. I Tube Repair Summary and Defect Trending l
The RFO 4 steam generator tube plugging summary is provided in Table 6. i A total of 12 tubes (8 in SG A and 4 in SG D) were plugged as a result of !
containing defects which met or exceeded the 40 percent throughwall l
Technical Specification plugging criteria. Allidentified defects were caused i by anti-vibration bar wear. The largest defect identified measured 55%
throughwall. Following the RFO 4 tube plugging operation, a cumulative total of 36 tubes had been plugged in all four steam generators. This represents j 0.16 percent of the total 22,504 tubes, Table 7. A complete listing of all tubes l plugged to date is provided in Table 8. !
Prior to RFO 4, a total of six tubes had hot leg 1600 plugs removed and replaced with 1690 plugs. The six removed plugs were of a heat which was ;
susceptible to stress corrosion cracking and represented 100 percent of the susceptible population. A recent addendum to a Westinghouse Steam Generator Tube Plug Integrity Summary Report, Reference 7, identified the i need to also replace cold leg plugs which were made of susceptible heats. !
Of the six cold leg 1600 plugs recommended for replacement, one was replaced during RFO 4 (SG A R7/C56) with an 1690 plug. The other five, !
which are in SG B and SG C, are scheduled to be replaced during a future -
outage in which these steam generators are opened. Table 9 provides a summary of the Seabrook steam generator tube plug replacement history. !
A study was performed to assess the growth rate of AVB flaws from September 1992 (RFO 2) to November 1995 (RFO 4). The study included !
172 AVB flaws >20 percent TW in RFO 4. ECT data from RFO 2 (September .
1992) was reanalyzed at each of the RFO 4 flaw locations to determine the precise flaw depth. The study, which is summarized in Table 10, determined that:
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- 1. AVB flaws can initiate at any time.
- 2. The growth rate of AVB flaws is highest during the first cycle in which a flaw initiates.
, 3. For flaws >10 percent TW in RFO 2, the average growth rate during j subsequent cycles was 4.5 percent TW per cycle.
i 4. The maximum growth rate observed over the two cycle period was 37 l percent TW (or 19 percent per cycle). This maximum growth rate was observed at both a newly initiated and a pre-existing flaw location.
3.0 Conclusions l - A state of the art eddy current examination of Seabrook SG A and SG D was ,
performed during RFO 4. The overall condition of the steam generator tubes remains excellent. No primary or secondary side tube corrosion (i.e. pitting, i cracking, IGA or wastage) was observed. The only' service induced tube .
degradation identified was AVB wear, which is a common degradation q mechanism for Model F steam generators. ;
i Concerns about tube cracking, based on NRC Generic Letter 95-03 and 5 Callaway experience, are considered to be addressed by the examination of expansion transitions, small radius U-bends and dent locations with EPRI -
NDE Guidelines Appendix H qualified NDE techniques.
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':l 4.0 References
- 1) " Millstone Point Unit 3 and Seabrook Steam Generator Eddy Current Data Analysis Guidelines Manual, Revision 2", ES-WC-94-033, November 1995.
- 2) "MP3 and Seabrook Qualification of 40 Inches /Second Data Acquisition ,
Speed for Steam Generator Tubes", ES-WC-95-096, April 27,1995. l
- 3) NRC Generic Letter 95-03, "Circumferential Cracking of Steam Generator Tubes", April 28,1995. i
- 4) EPRI PWR Steam Generator Examination Guidelines: Revision 4, Draft, i September 26,1995.
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- 5) A.W. DeAgazio (NRC) to T.C. Feigenbaum, " Request for Additional !
Information Related to Generic Letter 95-03", September 12,1995.
- 6) T.C. Feigenbaum to U.S. Nuclear Regulatory Commission, " Response to Request for Additional Information Related to Generic Letter 95-03",
NYN-95083, October 23,1995. l l
- 7) WCAP-12245 Revision 3, Addendum 4," Steam Generator Tube Plug Integrity Summary Report", May 1995.
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TABLE 1 CRITERIA FOR INITIAL SAMPLE SELECTION SEABROOK STEAM GENERATOR EXAMINATION l
FULL LENGTH BOBBIN COIL EXAMINATION INSPECTION CRITERIA NUMBER OF TESTS SG A SG D Previous Flaws 120% TW RFO2 19 25 Previous Flaws 10 - 19% TW RFO2 19 25 All Known Tubes with AVB Flaws from 313 289 MP3 and SBK Steam Generators Rows 2 25 Not inspected in RFO2 1062 1073 50% Row 1 (Tubes inspected in RFO2 63 61 Not included)
Perimeter Tubes 110 111 !
Random Sample (Rows 2 - 24 Not 834 836 Inspected in RFO2)
Totals 2420 2420 NOTE: Tubes which met more than one criteria are included in the first category only.
CECCO PROBE EXAMINATION INSPECTION CRITERIA NUMBER OF TESTS SG A SG D Random Samples of 500 Tubes from 500 500 Callaway Hot Leg Top-of-Tubesheet Cracking Region 1 1
I ROTATING PLUS-POINT PROBE EXAMINATION {
INSPECTION CRITERIA NUMBER OF TESTS SG A SG D 20% Sample of Row 1 U-bends 25 l
25 ROTATING 3-COIL PROBE EXAMINATION INSPECTION CRITERIA l NUMBER OF TESTS SG A SG D Tubes susceptible to PWSCC due to 12 12 geometry variations
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TABLE 2
SUMMARY
OF TESTS PERFORMED SEABROOK STEAM GENERATOR EXAMINATION-RFO 4 ;
i SG A SG D L TEST METHOD AREA EXAMINED HOT COLD HOT COLD TOTAL Bobbin Full Length (*) l 439 2161 435 2194 4867 Cecco 12" Above TS to 501 0 504 0 1005 i Tube End U-bend RPC Row 1 U-bend l 24 0 26 0 50 3-Coil RPC Dents & Dings l 12 0 12 0 24 ,
NOl by Bobbin l 1 0 1 3 1
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- Several tubes were examined partiallength from both hot and cold legs. !
.- j TABLE 3
SUMMARY
OF EXAMINATION RESULTS l
SEABROOK STEAM GENERATOR EXAMINATION-RFO 4 l I
ANTI VIBRATION BAR WEAR MAXIMUM FLAW DEPTH PER TUBE l l
% TW SG A SG D TOTAL l 10-19% 32 54 86 20 29% 21 30 51 30-39% 8 11 19 l !
2 40% % 8 4 12 l NON-AVB FLAWS MAXIMUM FLAW DEPTH PER TUBE l
%TW SG A SG D TOTAL 10-19% 14 11 25 l 20-29% 8 4 12 l 3 30-39 % 0 0 0 l 2 40% 0 0 0 l )
NON-FLAW INDICATIONS '
NUMBER OF TUBES !
INDICATION SG A SG D TOTAL Manufacturing Buff Mark 70 98 168 Tangential Flag Signal 69 52 121 Non-Quantifiable Signal
- 11 13 24 (NOS, DTS, DSS)
- Non-Flaw by RPC or No Change from Baseline Exam
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TABLE 4 -
SUMMARY
OF TOP-OF TUBESHEET TUBE I DEPOSIT HEIGHT MEASUREMENTS i
1 SEABROOK REFUELING OUTAGE NO. 4 l
1 Sludge SGA SGD Height
- Hot Cold Hot Cold i 1-1.99" 8 1 6 26 :
2-2.99" 8 6 5 7 i 3-3.99" 1 0 0 3 4 4-4.99" 0 0 0 0 l 1 5.00" 3 0 6 0 !
Values less than 1" can not be accurately measured by ECT and should be considered to have no reportable deposit accumulation. !
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TECHNICAL SPECIFICATION EVALUATION ;
SEABROOK STEAM GENERATOR EXAMINATION RFO 4 :
l INITIAL SAMPLE f i
- TUBES EXAMINED 2424 2443 !
- TUBES DEGRADED 31 28 !
% TUBES DEGRADED 1.28 % 1.15% !
- TUBES DEFECTIVE 7 3 .
% TUBES DEFECTIVE 0.29% 0.12 % ,
TECH SPEC CATEGORY C-2 C-2 l NOTE: 1) This table includes only those tube flaws which exhibited >10%
further wall penetration since the previous examination, based on reanalysis of previous ECT data. (Example: One of the 8 plugged tubes in SGA did not exhibit > 10% flow growth and was ;
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- 2) The number of tubes examined includes the S (6%),2S (12%) :
and 4S (24%) Technical Specification samples.
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i TABLE 6 l
STEAM GENERATOR TUBE PLUGGING
SUMMARY
I SEABROOK REFUELING OUTAGE NO. 4 TUBES PLUGGED DUE TO DEFECTS > 40% TW i ECT SG ROW COL %TW DEFECT LOCATION SIGNAL AMPL. :
A 46 62 40% AV3 3.0V A 46 64 52 %,43 % AV3, AV4 4.3V, 2.2V A 54 65 47%, 40% - AV3, AV4 4.3v, 3.0V A 46 66 50 % AV2 4.7V !
A 54 67 42 %,47 % AV2, AV3 3.3V, 4.3V l
A 56 82 55 % AV5 5.3V A 51 92 44 % AV5 3.6V A 49 96 51 % AV5 4.6V D 42 53 42 % AV4 3.3V D 47 55 41 %,49 % AV2, AV4 3.1V, 4.7V !
D 47 56 45% AV2 3.8V I D 49 64 43% AV4 3.4V i
COLD LEG TUBE PLUG REMOVAL AND REPLACEMENT
A 7 56 l
- Inconel 600 plugs replaced with inconel 690 plugs l
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TABLE 7 l
i CUMULATIVE SEABROOK STEAM GENERATOR TUBE PLUGGING
SUMMARY
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FOLLOWING REFUELING OUTAGE NO. 4 j SG A SG B SG C SG D TOTAL :
- Tubes Plugged (RFO 4) 8 - - 4 12 !
Cumulative # Tubes Plugged 12 6 13 5 36 l t
% of Tubes Plugged 0.21% 0.11 % 0.23% 0.09 % 0.16 % ;
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STEAM GENERATOR TUBE PLUGGING HISTORY l SEABROOK UNIT 1 l
SG Row Col % TW (Field Call) Location Volts Reason Dsc 1979 - Fabrication A 42 101 Unknown l B 8 107 Bare Hole B 8 115 Bare Hole l
C 24 20 Unknown !
C 26 84 Unknown May 1984 - Preservice C 54 51 Overexpansion ;
C 55 54 Overexpansion j C 55 59 Overexpansion :
Mar 1985 - Preservice A 49 39 Hydro Leak !
A 39 49 Hydro Leak i May 1985 - Preservice A 7 56 84 % 03H + 1.9' 1.9V Freespan Defect Bsseline B 40 63 95% AV4 + 11.5" 1.8V U-bend Defect B 36 79 72 % TSH + 11.4" 0.8V Freespan Defect Aug 1991 - RFO 1 B 27 24 37 % 06H + 4.1" 4.8V MBM*
C 31 12 N/A N/A N/A Loose Part '
C 32 12 N/A N/A N/A Loose Part i C 31 13 N/A N/A N/A Loose Part C 32 13 N/A N/A N/A Loose Part l C 51 50 36 % AV6 1.7V Wear
- C 50 95 37 % AV5 1.8V Wear
- C 48 98~ 36 % AV4 1.7V Wear
- C 11 120 38 % 07C + 27.3" 0.4V Freespan Flaw
- l D 47 54 35% AV2 1.8V Wear
- May 1994 RFO 3 B 51 61 40 %,50 % AV3,AV4 2.9V, 6.5V Wear Nov 1995 - RFO 4 A 46 62 40% AV3 3.0V Wear l A 46 64 52 %,43 % AV3,AV4 4.3V, 2.2V Wear l A 54 65 47%,40% AV3,AV4 4.3V, 3.0V Wear A 46 66 50 % AV2 4.7V Wear A 54 67 42%,47% AV2, AV3 3.3V, 4.3V Wear A 56 82 55% AV5 5.3V Wear A 51 92 44% AV5 3.6V Wear A 49 96 51 % AVS 4.6V Wear j D 42 53 42% AV4 3.3V Wear l D 47 55 41 %,49 % AV2, AV4 3.1 V, 4.7V Wear l D 47 56 45% AV2 3.8V Wear D 49 64 43% AV4 3.4V Wear
- Plugged Preventatively l l
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TABLE 9 l STEAM GENERATOR TUBE PLUG REPLACEMENT HISTORY SEABROOK UNIT 1 j 1
Plug Replacement 1600 1690 l Date SG Row Col Side Old Heat New Heat !
Sep 1992 - RFO 2 A 7 56 Hot Leg NX2337 NX6977 May 1994 - RFO 3 8 36 79 Hot Leg NX2387 NX7252 8 40 63 Hot Leg NX2387 NX7252 C 54 51 Hot Leg NX2387 NX7252 C 55 54 Hot Leg NX2387 NX7252 !
C 55 59 Hot Leg NX2387 NX7252 Nov 1995 - RFO 4 A 7 56 Cold Leg NX2387 NX7252 1
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TABLE 10 l
SUMMARY
OF AVB FLAW GROWTH RATES !
SEABilOOK STEAM GENERATOR EXAMINATION i (SEPTEMBER 1992 - NOVEMBER 1995) l l
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%TW SGA SGD Total i
Sept 1992 Avg. Growth Avg. Growth Avg. Growth
- Flaws (1992-1995) # Flaws (1992-1995) # Flaws (1992-1995) j
< 10% 31 24% TW 28 24% TW 59 24% TW 10-19 % 20 14% TW 37 9% TW 57 11% TW !
20-29% 15 12% TW 36 6% TW 51 8% TW i 30-39% 3 8% TW 2 11% TW 5 9% TW NOTE: September 1992 ECT data was reanalyzed using the same sizing method as used in i 1995.
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! ATTACHMENT 1 1
LISTING OF ALL FLAWS > 20% TW DURING RFO 4 SEABROOK - SG A l
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'Date: 12/12'/95 !
Component: S/G A i
Outage: 95-1 SEABROOK !
Page: 1 ?
INDICATIONS 20 TO 100% THROUGHWALL i
ROW COL VOLTS PERCENT LOCATION 1 99 l 0.6 21 01C 12.7~ !
18 70 0.6 26 TSH 16.7 19 40 l 1.3 24 AV1 0.0 :
26 26 0.2 27 02C 6.2 !
! 27 80 0.7 25 01C 13.5 '
l 28 59 0.3 25 03H 10.1 28 87' O.3 22 03C 0.0 31 12 1.8 31 AV5 0.0 i 34 12 0.3 28 04C 17.6 i l 36 61 1.3 24 AV3 0.0 i i
36 81 0.9 21 AV2 0.0 t 40 90 1.0 21 AV3 0.0 i 40 90 1.1 23 AV2 0.0 i l 41 41 0.9 21 AV4 0.0-l 41 68 0.9 20 AV3 0.0 3
l 41 103 1.2 25 AV5 0.0 l 42 72 2.0 34 AV3 0.0 }
, 43 77 1.7 31 AV4 0.0 l
! 43 77 1.0 23 AV3 0.0 4
! 43 77 1.4 28 AV5 0.0 !
! 46 61 10.7 22 AV4 0.0 l 46 61 1.0 20 AV3 0.0 :
1 46 61 1.7 29 AV2 0.0 1
46 62 2.3 34 AV4 0.0 i
46 62 3.0 40 AV3 0.0 46 64 4.3 52 AV3 0.0 46 64 1.1 21 AV2 0.0 t 46 64 2.2 43 AV4 0.0 46 66 l 2.2 34 AV3 0.0 l 46 66 1.8 29 AV4 0.0 :
46 66 1.2 22 AV5 0.0 46 66 i 4.7 50 AV2 0.0 47 61 2.0 31 AV4 0.0 !
47 85 1.1 23 AV5 -0.2 47 96 1.2 26 AV6 0.2 47 96 2.3 37 AV3 0.0 47 96 2.2 36 AV4 0.0 !
48 60 1.3 24 AV6 0.0 t 48 95 0.S 22 AV6 0.2 49 64 1.1 21 AV1 0.0 49 67 1. 2 ' 23 AV3 0.0 49 69 1.2 23 AV4 0.0 '
49 69 1.5 26 AV3 0.0 l
49 88 1.6 28 AVS 0.0 49 88 0.9 20 AV4 0.0 l
. , . , . - . . . _ _..__i_ _ . . - _ .
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Date: 12/12/95 -
Component: S/G A Outage: 95-1
- SEABROOK I Page: 2 '
INDICATIONS 20 TO 100% THROUGHWALL i i
ROW COL VOLTS PERCENT LOCATION !
49 93 1.3 28 AV4 0.0 i 49 93 2.2 36 AV5 0.0 i 49 96 2.6 38 AV3 -0.2 49 96 1.0 12 4 AV4 0.0 :
l 49 96 4.6 51 AV5 0.0 '
50 85 1.1 24 AV4 0.0 i 50 85' 1.3 26 AV3 0.0 50 88 1.0 22 AV6 0.0 50 95 1.7 31 AV5 0.0 !
50 95 1.3 28 AV6 0.0 '
50 95 1.0 23 AV4 0.0 51 87 0.4 24 08C 1.0 51 90 1.1- 22 AV5 0.0 !
- 51. 92 3.6 44 AV5 0.0 !
51 92 1.0 21 AV4 0.0 :
52 87 1.4 26 AV3 0.0 !
52 87- 1.1 22 AV6 0.0 52 87 1.8 31 AV4 0.0 52 88 1.0 21 AVS 0.0 :
52 88 1.5 28 AV4 0.0 i 52 89 1.2 24 AV6 0.0 i 52 89 1.0 21 AV5 0.0 ,
53 87 0.9 20 AV5 0.0 i 54 65 1.9 30 AV2 0.0 l 54 65 4.3 47 AV3 0.0 54 65 {
3.0 40 AV4 0.0 54 67 2.2 34 AV4 0.0 :
54 67 1.4 25 AV5 0.0 l 54 67 3.3 42 AV2 0.0 l 54 67 4.3 47 AV3 0.0 l 54 67 2.0 32 .AV1 0.0 i 56 82 5.3 55 AV5 0.0 Number of Indications : 77 Number of Tubes : 45 i
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- - ~ . -.-n.. ..n.---,...--..s .as-1 a a .-..-n..-. s _. . ~ -_- a-.e-..+a - . -.n ..a~. .- u .n. . . -,,...a-- -.s-... --- . - - -,. . - ---
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ATTACHMENT 2 LISTING OF ALL FLAWS > 20% TW DURING RFO 4 1
I SEABROOK - SG D
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f Date: 1*2/12/95 i Component: S/G D :
Outage: 95-1 I SEABROOK ;
Page: 'l .i INDICATIONS 20 TO 100% THROUGHWALL ROW COL VOLTS PERCENT LOCATION i 27 8 1.0 22 AV6- 0.0 28 8 1.9 32 AV6 0.0 L 32 12 0.9 '21 AV5 0.0 35 73 0.4 22 01C 2.4 36 82 1.1 23 AV2 0.0 l
- 37 70 0.8 21 AV2 0.0 1 37 70 1.9 33 AV3 0.0 t 37 70 1.0 24 AV1 0.0 !
37 70 0.9 22 AVS 0.0 i 37 70 0.9 22 AV4 0.0 l 37 77 1.0 22 AV4 0.0 ;
37 77 0. 9 - 21 AV3 0.0 j 39 17 1.6 30 AV4 0.0 !
40 66 1.1 23 AV2 0.0 :
40 '75 1.5 29 AV3 0.0 i 40 75 1.1 23 AV2 0.0 40 76 1.6 29 AV4 0.0 40 76 0.9 20 AV5 0.0 t 40 76 1.9 33 AV2 0.0 '
40 76 2.0 34 AV3 0.0 !
41 45 1.3 25 AV3 0.0 l 41 45 1.7 29 AV5- 0.0 !
41 45 1.4 27 AV4 0.0 :
41 56 1.2 24 AV5 0.0 !
41 56 1.6 29 AV2 0.0 i 42 24 1.1 23 AV4 0.0 ;
42 46 0.9 20 AV3 0.0 I 42 50 1.6 29 AV2 0.0 i 42 52 0.9 20 AV6 0.0 ;
42 52 1.3 25 AV5 0.0 :
42 52 1.1 23 AV2 0.0 l 42 53 3.3 42 AV4 0.0 ;
42 53 1.0 21 AV3 0.0 i 42 76 1.0 22 AV2 0.0 !
42 76 2.1 34 AV5 0.0 l 42 76 1.5 29 AV4 0.0 ,
42 76 0.9 20 AV3 0.0 i 43 51 1.0 21 AV5 0.0 i 46 30 1.2 25 AV4 0.0 '
46 30 1.0 23 AV5 0.0 !
46 56 1.2 24 AV1 0.0 i 46 56 1.4 27 AV4 0.0 l 46 59 1.1 23 AV2 0.0 !
46 59 1.3 25 AV3 0.0 '
46 59 1.8 31 AV4 0.0 j l
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4 Date: 12/12/95. I Component: S/G D l Outage: 95-1 SEABROOK ,
Page: 2 INDICATIONS 20 TO 100% THROUGHWALL ROW COL VOLTS PERCENT LOCATION !
46 59 2.0 33 AV5 0.0
-46 59 1.0 21 AV6 0.0 )
46 -78 0.9 20 AV4 0.0 46 78 1.5 28 AV5 0.0 47 26 0.9 21 AV3 0.0 47 26 1.3 26 AV4 0.0 47 44 1.7 30 AV6 -0.0 i 47 47 1.9 34 AV2 0.0 47 47 1.2 27 AV5 0.0 47 47 1.7 32 AV4 0.0 47 47 1.2 27 AV3 0.0 l 47 48 0.7 20 AV4 0.0 1 47 48 1.0 25 AV3 0.0 i 47 55 1.0 21 AV1 0.0 '
47 55 3.1 41 AV2 0.0 47 55 2.8 39 AV3 0.0 47 55 4.7 49 AV4 0.0 i 47 55 2.2 34 AV5 0.0 1 47 56 3.8 45 AV2 0.0 l 47 56 2.6 37 AV3 0.0 48 28 1.3 26 AV4 0.0 48 28 0.9 20 AVS 0.0 1 48 28 1.5 29 AV3 0.0 l 48 45 0.4 23 02C 26.6 i 49 50 1.6 29 AV5 0.0 l 49 58 1.3 25 AV2 0.0 49 58 1.5 28 AV3 0.0 49 64 1.5 28 AV3 0.0 49 64 1.0 21 AV1 0.0 49 64 1.1 23 AV2 -0.1 49 64 3.4 43 AV4 0.0 49 64 1.6 29 AV5 0.0 49 68 1.0 22 AV3 -0.4 49 68 2.2 34 AV4 -0.1 49 69 0.7 20 AV6 0.0 49 69 0.8 21 AV1 0.0 49 69 1.0 23 AV5 0.0 49 69 1.0 23 AV4 0.0 o49 69 1.0 23 AV3 0.0 49 69 0.8 21 AV2 0.0
-49 70 0.8 20 AV4 0.0 49 70 0.8 21 AV5 0.0 49 70 1.0 24 AV2 0.0 49 85 1.8 31 AV2 0.0 49 85 2.3 36 AV3 0.0 l
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- l Date: 12/12/95 l Component: S/G D Outage: 95-1 l SEAEROOK
( Page: 3 l
! INDICATIONS 20 TO 100% THROUGHWALL l ROW COL VOLTS PERCENT LOCATION 49 85 0.9 20 AV4 0.0 49 85 1.4 27 AV5 0.0 l 51 35 1.0 25 TSC 4.3 l 51 36 1.8 29 AV6 21.7 l l 52 33 1.5 28 AV4 0.0 l 52 35 1.0 23 AV5 0.0 )
l 52 37 0.8 20 AV6 0.0 52 37 1.4 27 AV5 0.0 l 52 37 1.5 29 AV4 0.0 :
52 57 1.1 23 AV5 0.0 l 52 57 1.2 24 AV4 0.0 l 56 41 1.1 22 AVS 0.0 l 56 43 0.4 26 04C -1.2 i 56 46 0.9 23 AV5 0.0 56 46 2.1 36 AV4 0.0 56 76 1.2 25 AV4 0.0 56 76 0.9 21 AV5 0.0 l 56 76 1.0 22 AV6 0.0 {
i l
Number of Indications : 108 l Number of Tubes : 49 l
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