ML20078J846
| ML20078J846 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 01/31/1995 |
| From: | Denton R BALTIMORE GAS & ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9502080255 | |
| Download: ML20078J846 (3) | |
Text
Rostar E. DEKrON Baltimore Gas and Electric Company Vice President Calvert Cliffs Nuclear Power Plant Nuclear Energy 1650 Calvert Cliffs Parkway Lusby, Maryland 20657 410 586-2200 Ext. 4455 Incal 410 260-4455 Baltimore January 31,1995 U. S. Nuclear Regulatory Conunission Washington, DC 20555 ATTENTION:
Document Contre! Desk
SUBJECT:
Calvert Cliffs Nt clear Power Plant Unit Nos.1 & 2: Docket Nos. 50-317 & 50-318 Westinghouse Alloy 600 Steam Generator Mechanical Plugs Corrosion Algorithm Resision
REFERENCE:
(a)
Letter from Mr. N. Liparulo (Westinghouse) to NRC Document Control Desk, dated January 25,1995, Westinghouse Steam Generator TuSc Mechanic 11 Plug Corrosion Algorithm Revision (b)
Letter from Mr. G. C. Crect (BGE) to NRC Document Control Desk, dated August 9,1991, Response to NRC Bulletin 89-01, Supplement 2. " Failure of Westinghouse Steam Generator Tube Mechanical Plugs" The following status is provided in response to the NRC staffs request at a meeting held on December 22,1994, concerning recent field experience with Westinghouse Alloy 600 Thermally Treated (TT) mechanical plugs. This letter serves to provide the staff with our intended response to this latest field data.
BACKGROUND In December 1994, Westinghouse notified us of recent field experience with Alloy 600 TT mechanical plugs that necessitated a revision to the corrosion algorithm presented in WCAP-12244, Revision 3 (Reference 4 of NRC Bulletin No. 89-01, Supplement 2, " Failure of Westinghouse Steam Generator Tube Mechanical Plugs"). Subsequent to that, Westinghouse provided us with the results of the revised algorithm which they issued as Addendum 3 to WCAP-12244, Revision 3 on January 25,1995 (Reference a). Based on these results, the emSst projected repair date for Calvert Cliffs is 2005 (see ). This projected date is unchanged from what we reported in Reference (b) for the remaining plugs. In the event that the revised algorithms reported in Reference (a) are not acceptable to the NRC, the 9502080255 950131 g-I l PDR ADOCK 05000317 00l(i
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Document Control Desk January 31,1995 Page 2.
4 ongmal basis for a Justification for Continued Operation provided in WCAP-12244 continues to apply for
- Calvert Cliffs Nuclear ' Power Plant until the issue is resolved and appropriate actions can be developed.
We believe the issue is being effectively managed by the industry, and that the issue does not pose an immediate safety concern to the health and welfare of the public.
CALVERT CLIFFS' CURRENT STATUS 8
At present, Calvert Cliffs Units 1 and 2 have a total of 138 and 104 installed Westinghouse Alloy 600 'IT mechanical plugs, respectively, that have not been repaired. These plugs are all located in the cold legs of the steam generators. Of these, a total of seven plugs (five in Unit I and two in Unit 2) are located in rows I through 4 where plug top release may lead to tube perforation. All Westinghouse Alloy 600 plugs previously installed in the hot legs of both Units I and 2 steam generators have been removed and replaced 4
with Westinghouse Alloy 690 mechanical plugs. Attachment (1) provides the installation date, heat numbers, and projected repair date (from Reference a) for the Westinghouse Alloy 600 mechanical plugs that are currently in service at Calvert Cliffs.
As we committed in Reference (b), we will continue to track Westinghouse Alloy 600 plugs installed in Calvert Cliffs steam generators for repair / replacement. In accordance with Reference (a), we will take remedial action during refueling outages to repair / replace any Alloy 600 plug prior to the end of its estimated lifetime.
i Should you have questions regarding this matter, we will be pleased to discuss them with you.
Very truly yours,
)
5 b
k RED /GT/ dim
Attachment:
(1)
Westinghouse Alloy 600 Mechanical Tube Plugs Installed in the Steam Generators at Calvert Cliffs Nuclear Power Plant j
cc:
D. A. Brune, Esquire J. E. Silberg, Esquire L. B. Marsh, NRC D. G. Mcdonald, Jr., NRC T. T. Martin, NRC P. R. Wilson, NRC R. I. McLean, DNR J. II. Walter, PSC N. Liparuto, Westinghouse I
ATTACIIMENT (1)
WESTINCIIOUSE ALLOY 600 MECilANICAL TUBE PLUGS INSTALLED IN Tile STEAM GENERATORS AT CALVERT CLIFFS NUCLEAR POWER PLANT All Westinghouse OD mechanical tube plugs previously installed in the hot legs of the Units 1 and 2 steam generators have been removed and replaced with E Alloy 690 mechanical tube plugs.
Summary of locations, installation dates, heat numbers, and projected repair date for the W Alloy 600 mechanical tube plugs that remain installed in the cold legs of the Units 1 and 2 steam generators. The projected dates are from the revised corrosion algorithm (Reference a).
Number IIeat Projected Location Installation of Plugs Number Repair Date SG11 06/82 15 2387 2072 11/83 3
1989 2073 05/85 6
1989 2075 05/85 6
2387 2075 07/85 1
2387 2075 05/88 42 5222 2008 06/90
_9 6323 2009 82 SG 12 06,82 11 2387 2072 11/23 2
1989 2073 05/85 7
2387 2075 07/85 4
2387 2075 05/88 27 5222 2008 07/89 1
6323 2009 09/89 1
6323 2009 06/90 3
6323 2009 56 SG 21 11/82 1
2387 2072 05/84 4
1989 2074 10/85 9
2387 2077 05/87 38 3513 2005 06/89 12 6323 2009 07/89
_3 6323 2009 67 SG 22 11/82 1
2387 2072 05/84 2
1989 2074 05/87 20 3513 2005 10/85 4
2387 2077 06/89
.l 0 6323 2009 37 e.
, Sh 1