ML20098B098
| ML20098B098 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 09/26/1995 |
| From: | Dennis Morey SOUTHERN NUCLEAR OPERATING CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-95-03, GL-95-3, NUDOCS 9510020152 | |
| Download: ML20098B098 (3) | |
Text
1 Southern Nucl:tr Operating Company
- g Post Offico Box 1295 Birminghtm. Alabama 35201
+
Telephone (205) 868 5131
'o.ve worey Southem Nudear Operating Company
' Vice President I**
September 26, 1995 Docket Nos.
50-348 50-364 U. S. Nuclear Regulatory Commission ATfN.: Document Control Desk Washington, D. C. 20555 Joseph M. Farley Nuclear Plant I r auest for Additional Information Concerninn Generic Letter 95-03 Ladies and Gentlemen:
By letter dated Septanber 6,1995, the NRC requested additional information relative to Southern Nuclear's response to Generic Letter 95-03 for Farley Nuclear Plant. Subsequent to the receipt of the September 6,1995 letter, an additional request for information on the use of terrain mapping for rotating pancake coil inspections was reeived. Responses to the Staffs questions are provided below:
1.
RAI Question: In several instances (e.g., preventively plugging, recovering tubes, future inspection plans), references to "small radius U-bend tubes" were made. Clarify what is meant by small radius (i.e., Row 1, Row 2, etc.).
SNC Response: At Faricy Nuclear Plant, "small radius U-bends" refers to the U-bends of rows 1 and 2.
RAI Question: Clarify the expansion criteria to be used if an indication is detected in a small radius U-bend tube in the one steam generator inspected in Unit 2.
SNC Response: If a flaw u detected in a small radius U-bend of the steam generator inspected in Unit 2, the inspection will be expanded to include all row I and 2 U-bends in all three steam generators.
2.
RAI Question: Clarify what is meant by "no field calls" if circumferential indications exceeding 181* have been found.
SNC Response: A sentence in Section 4.0, Summary, of the response states, 4
"Since the initial 100% RPC inspections in 1990 (Unit 1) of the hot leg tube sheet expansions, no field calls for circumferential indications exc:cding are lengths of 181' have been found." The intent of this passage was to state that following the first inspections at which the RPC probe was available, no circumferential flaws
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i have been detected which exceed 181* in circumferential extent. However, the i
1990 date is in error. As reported in Section 2.1.c of the response, the initial 100% RPC iw-h occurred in March 1991, not 1990. Followmg the Spring 1991 inspection, the 181* flaw discovered in Unit 1 in October 1992 is the largest circumferential flaw #W De largest flaw found in Unit 2 is 122* found in i
October 1993.
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3.
RAI Question: Clarify the inspection results from the sleeved tubes (i.e., were other forms of degradation other than from corrosion found during the inspections).
SNC Response: As reported in Unit 2 LER 95-001-00, one tube was plugged j
due to the inability to inspect the sleeved portion of the tube. A bulge in the wall of the tubesheet sleeve prevented passing a probe through the sleeve.
l 4.
During the Maine Yankee outage in July / August 1994, several weaknesses 1
were identified in their eddy current program as detailed in NRC Information Notice 94-88, " Inservice Inspection Deficiencies Result in Severely Degraded i
Steam Generator Tubes". In Information Notice 94-88, the staff observed that several circumferential indications could be traced back to earlier inspections when the data was remnalyzed uring terrain plots. These terrain plots had not been generated as pad of the original field analysis for these tubes. For the rotating pancake coil (RPC) examinations performed at your plant at locations susceptible to circumferential cracking during the previous inspection (i.e., previous inspection per your Generic Letter 95-03 response),
i discuss the extent to which terrain plots were used to analyze the eddy current data. If terrain plots were not routinely used at locations susceptible to circumferential cracking, discuss whether or not the RPC eddy current data l
has been reanalyzed using terrain mapping of the data. If terrain plots were not routinely used during the outage and your data has not been reanalyzed with terrain mapping of the data, discuss your basis for not reanalyzing your previous RPC data in light of the findings at Maine Yankee.
l Discuss whether terrain plots will be used to analyze the RPC eddy current j
data at locations susceptible to circumferential cracking during your next i
steam generator tube inspection (i.e., the next inspection per your Generic Letter 95-03 response).
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Y U. S. Nuclear PP *w C-minaion Page 3 SNC Response: Terrain plots were routinely used to analyze eddy current data from RPC inspectens during the Farley steam generator inspections discussed in our response to Generic Letter 95-03 dated June 26,1995. Terrain plots will be used to analyac the RPC eddy current data at locations susceptible to circumferential cracking at the next Unit I and 2 steam generator inspections.
If there are any questions, please advise.
Respectfully submitted, SOUTHERN NUCLEAR OPERATING COMPANY
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Dave Morey REM /maf:CCGLRAI. DOC 1
SWORN TO AND SUBSCRIBED BEFORE ME cc:
Mr. S. D. Ebneter THIS db DAY OF Am/4.1995
. Ross d
- 7/Ev i
Mr. T. A. Reed
" Notary Public l'
My Commission Expir mea /977 4
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