ML20092K233
| ML20092K233 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 09/19/1995 |
| From: | Tuckman M DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-95-03, GL-95-3, NUDOCS 9509250289 | |
| Download: ML20092K233 (5) | |
Text
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P.O. Bat 2006 Senior VicePresiaent Darlane,NC282011006 NuclearGeneration (704)3822200 DMice (704)382-4360 Fax.
DUKEPOWER September 19,1995 -
U.S. NuclearRegulatory Commission ATTN: Document ControlDesk Washington, D.C. 20555
Subject:
Catawba Nuclear Station Units 1 & 2 Docket Nos. 50-413,414 Response to Request for Additional Information Concerning Generic Letter 95-03 Gentlemen:
By letter dated June 27,1995, Duke Power Company submitted a response for Catawba, McGuire and Oconee Nuclear Stations to Generic Letter 95-03, Circumferential Cracking of Steam Generator Tubes. The NRC staffissued a request for additional information (RAI), dated September 1,1995, for Catawba Nuclear Station. Attached are the responses to the questions posed in the RAI for Catawba Nuclear Station.
I declare under penalty of perjury that these statements are tme and correct to th best ofmy knowledge.
Should you have any questions regarding this submittal, please contact D.B. Mayes at (704) 382-4211.
Very truly yours bd
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M.S. Tuckman Senior Vice President Nuclear Generation Attachment
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ATTACHMENT CATAWBA NUCLEAR STATION RESPONSE TO RAI FOR GL 95-03 1
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Attachment U.S. NRC
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September 19,1995 THE FOLLOWING RESPONSE IS PROVIDED FOR CATAWBA NUCLEAR STATION:
- 1. Catawba Unit 2 has thermally treated Alloy 600 tubing and stainless steel broached tube support plates. Catawba Unit 2 has not observed denting at tube support plate locations. Catawba Unit 2 has not observed cracking at any location.
2.
Rows 1,2,3, and 4 at Catawba Unit I were inspected at the last refueling outage (2/95, EOC-8).
3.
If one circumferential crack is observed in an area susceptible to circumferential cracking, then,100% of the susceptible area will be inspected. The Row I and 2 U-bends will be inspected with a rotating pancake coil.
4.
Catawba Unit 2 has 141 tubes expanded at two locations into the tube support plate to prevent vibration in the preheater section of all steam generators. These tubes are located in the cold leg of the steam generators. Catawba Unit 2 has thermally treated Alloy 600 tubing. Catawba Unit 2 has not observed cracking at any location. Other Locations are more susceptible to cracking than the expanded locations due to temperature and residual stress. The area is not currently believed to be susceptible to cracking.
5.
A 100% full length bobbin preservice inspection is planned for Catawba Unit I replacement steam generators prior to their installation into containment. Please reference the letter to the U.S. NRC from M.S. Tuckman, dated September 30, 1994, Replacement Steam Generator Proposed Tech Spec Amendment.
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( m FORll#0RMATl0N ONLY 8
I Request for Additional Information L
Catawba Units 1 and 2 1.
It was indicated that Catawba Unit 1 is susceptible to circumferential cracking at dented locations; however, this region is not cited as a susceptible location for Catawba Unit 2.
Please clarify.
If susceptible, please submit the information requested in Generic Letter (GL) 95-03 per the guidance contained in the GL.
2.
Please clarify the outage during which the rotating pancake coil (RPC) examination of the U-bend portion of the tubes in Rows I, 2, 3, and 4 at Catawba Unit I were performed.
3.
Discuss the expansion criteria to be used during the Unit 2 inspections if circumferential. indications are. detected in the areas susceptible to l
circumferential cracking. Clarify the probe to be used for the-inspection of the row I and 2 U-bend tubes in Unit 2.
l 4.
Several plants with preheater model steam generators expanded tubes into i
the tube support plate in the preheater region to minimize the potential i
for vibration induced wear. Since these expansions contain similarities to other expanded regions which have experienced circumferential j
cracking, discuss whether or not this area is susceptible to circumferential cracking.
If this area is susceptible to circumferential cracking, please submit the information requested in Generic Letter (GL) 95-03 per the guidance contained in the GL.
5.
It is indicated that no tube inspections are planned for Unit I since.
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the steam generators are to be replaced. The staff notes that the technical specifications contain requirements pertaining to preservice l
inspections which may apply to the replacement steam generators.
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