ML17334A546
| ML17334A546 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 11/20/1997 |
| From: | Fitzpatrick E INDIANA MICHIGAN POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| AEP:NRC:1166AJ, NUDOCS 9711260075 | |
| Download: ML17334A546 (9) | |
Text
CATEGORY 1 I
REGULA'1 Y INFORMATION DISTRIBUTIO'A.
YSTEM (RIDS)
ACCESSION NBR:9711260075 DOC.DATE: 97/11/20 NOTARIZED: NO FACIL:50-316 Donald C.
Cook Nuclear Power Plant, Unit 2, Indiana M
AUTH.NAME AUTHOR AFFILIATION FITZPATRICK,E.
RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)
DOCKET ¹ 05000316
SUBJECT:
Informs NRC of results of SG eddy current tube insp subsequent tube repair activities performed during 1997 Unit 2 refueling outage.
D1STR1BUTTON CODE:
A001D CORTES RECETVED:LTR / ENCL I
STRE:
TITLE: OR Submittal:
General Distribution NOTES:
RECIPIENT ID CODE/NAME PD3-3 LA HICKMAN,J COPIES LTTR ENCL 1
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1 RECIPIENT ID CODE/NAME PD3-3 PD COPIES LTTR ENCL 1
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INTERNA DE NRR/DSSA/SCSB NRR/DSSA/SRXB OGC/HDS2 01 1
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0 1
1 1
0 NRR/DE/ECGB/A NRR/DRCH/HICB NRR/DSSA/SPLB NUDOCS-ABSTRACT 1
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EXTERNAL: NOAC 1
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0 NOTE TO ALL'"RIDS" RECIPIENTS:
PLEASE HELP US TO REDUCE WASTE. TO HAVE YOUR NAME OR ORGANIZATION REMOVED FROM DISTRIBUTION LISTS OR REDUCE THE NUMBER OF COPIES RECEIVED BY YOU OR YOUR ORGANIZATION, CONTACT THE DOCUMENT CONTROL DESK (DCD)
ON EXTENSION 415-2083 TOTAL NUMBER OF COPIES REQUIRED:
LTTR 14 ENCL 12
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indiana Michigan Power Company 500 Circle Drive Buchanan, Mi 491071395 N
IHOIANA NICNISAItI PQWM'ovember 20, 1997 Docket No.:
50-316 AEP:NRC:1166AJ U.
S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D. C.
20555
, Gentlemen:
II Donald C.
Cook Nuclear Plant Unit 2 STEAM GENERATOR 15 DAY INSPECTION REPORT Pursuant to the requirements of Cook Nuclear Plant Technical Specification 4.4.5.5a, this letter is to inform you of the results of our steam generator" eddy current tube inspection and the subsequent tube repair activities performed during the 1997 unit 2 refueling outage.
Eddy current inspections on the unit 2 steam generators tubes began on October 31, 1997.
All inspections and repairs were completed by November 5,
1997.
Inspections included a
50 0
bobbin coil examination of all inservice tubes in all four steam generators.
Additionally, a
20% top of the tubesheet rotating pancake coil inspection was conducted in one steam generator in compliance with our submittal letter AEP:NRC:1166T, dated June 27, 1995.
Repair activities were limited to plugging a total of five tubes.
The attachment to this letter provides the inspection
- findings, indication dispositions and the steam generator tube repair actions taken during the 1997 unit 2 refueling outage.
Sincerely, E.
E. Fitzp trick Vice President jen Attachment A. A. Blind A. B. Beach MDEQ -
DW & RPD NRC Resident Inspector J. A. Abramson 97li260075 97ll20 PDR
'ADOCK 050003ih P
PDR IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII.
ATTACHMENT TO AEP:NRC: 1166AJ 1997 UNIT 2 REFUELING OUTAGE STEAM GENERATOR EDDY CURRENT INSPECTION RESULTS AND TUBE REPAIR ACTIVITIES
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Attachment to AAEP:NRC:1166AJ Page 1
The table provides a summary of the 1997 unit 2 refueling outage (U2R97) steam generator (SG) inspection findings.
The results are presented for each SG, by degradation
- location, based upon technical specification plugging criteria.
Locations SG 21 SG 22 Ind Def Plg Ind Def Plg SG 23 Ind Def Plg SG 24 Ind Def Plg CLTSP HLTSP AVB U-Bend CLTS HLTS Misc.
Totals 1
1 1
4 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
5' 1
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
6 4
4 Table Acronym List CLTS CLTSP anti-vibration bar intersection cold leg tubesheet cold leg support plate intersection HLTSP Ind Misc.
hot leg support plate intersection indication miscellaneous Def HLTS defect hot leg tubesheet Plg pluggable indication U-Bend tight radius (row 1-2) u-bends As noted above, SG 21 had one pluggable indication.
The indication was located at Rl/C70, at the first cold leg support plate, and was estimated at 28% throughwall.
The indication is believed to have been caused by a burr or small foreign object located near the center of the quatrefoil support plate.
Previous inspections were last performed on this tube in
- 1988, during
'the original manufacturing baseline.
The tube was classified as having no detectable degradation in the baseline examination.
As a result of the lack of inspection history and unknown indication growth rate, this tube was conservatively plugged.
As a preventive measure, the surrounding tubes were inspected using both'obbin coil and rotating pancake coil inspection probes.
No additional indications were found.
SG 21 also was found to have four indications, contained within two tubes, of hot leg support plate wear.
These indications were sized using qualified techniques and found to have wear indications ranging from 4% to 11% throughwall.
As allowed by our technical specifications, these indications were left inservice.
No indications were detected in either SG 22 or SG 23 during the scheduled inspection.
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Attachment to AEP:NRC:1166AJ Page 2
In SG 24, tubes R33/C15, R33/C16, R33/C17 and R38/72 contained a
total of six single volumetric indications, all located near the top of the hot leg tubesheet.
The indications were characteristic of foreign object wear.
A data history search found that the tubes were last examined during the original baseline inspection (1988) at which time that were classified as having no detectable degradation.
The four tubes involved were subsequently plugged due to the lack of a qualified sizing technique.
As a result of the foreign object
- concern, the eddy current inspection scope was expanded to include the tubes surrounding the indications as well as 100% of the tubes (two rows in) around the periphery.
Eddy current testing did not produce evidence of a loose part near the four tubes in question.
- However, a possible loose part signal was reported in tubes R39/C69, R38/C70 and R38/C71.
During an expanded secondary side visual inspection, a foreign object (weld wire) was removed from this area of the tube bundle.
Throughout the inspection program, all tubes with manufacturing burnish marks (MBMs) were reviewed against the 1988 baseline inspection.
No changes were noted in any of these indications in any of the SGs.
A total of 90 dent indications, ranging in voltage from 3.0 to 16.24 volts, were reviewed in the four SGs.
The vast majority of these signals fell into the 3 to 6 volt range, with only two dents exceeding 10 volts.
Similar to our approach for MBMs, all dents reported during the,U2R97 inspection were to be reviewed against the 1988 data.
- However, three dent signals could not be reviewed in this fashion as the baseline data would not duplicate from the digital tape to optical disc.
These three dents were all believed to have been present during the baseline examination.
This confidence is based upon the successful matchup of the remaining (87) dent signals and the des'gn of our quatrefoil support plates which preclude inservice denting.
All three of the subject dents were recorded as being less than four volts during the U2R97 inspection and, therefore, not believed to be significant.
All of the remaining dent signals were confirmed to have been present in the baseline data.
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