ML20245D103
| ML20245D103 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 06/14/1989 |
| From: | Cruse C BALTIMORE GAS & ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| IEB-89-001, IEB-89-1, NUDOCS 8906260396 | |
| Download: ML20245D103 (3) | |
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BALTIMORE
' GAS AND ELECTRIC CHARLES CENTER. P.O. BOX 1475 '. CALTIMORE, MARYLAND 21203 l
. d CHARLES H. CRUSE j-MANAGER NUCLEAR ENGINEERING SEfMCES DEPARTMENT l
June 14,1989 h
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U. S. Nuclear Regulatory Commission Washington, DC 20555 l
ATTENTION:
Document Control Desk 1
SUBJECT:
Calvert Cliffs Nuclear Power Plant i
Unit Nos.1 & 2; Docket' Nos. 50-317 & 50-318 j
l Response to NRC Bulletin 89-01,- " Failure of Westinghouse Steam Generator Tube Mechanical Plues 1
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Gentlemen:
As requested, we are providing information that describes our. response to ' NRC Bulletin 89-01.
The Bulletin requires that licensees, (a) -determine if.Leertain mechanical plugs supplied by Westinghouse are installed in our Steam Generators ' and, j
(b) implement an action plan to ensure that these ' plugs will continue-to perform their intended design function. We are' committed to take the actions " described in th:
Attachment which meet the requirements of Bulletin 89-01.
Should you have any further questions regarding this matter, we' will be pleased to discuss them with you.
Very truly yours, r
! '>?tig V r+t4 d
./
l CHC/ PSF / dim Attachment cc:
' D. A. Brune, Esquire J. E.
Silberg, Esquire R. 'A. Capra, NRC fjb/7-S. A.McNeil, NRC W. T. Russell, NRC II. Eichenholz/V. L. Pritchett, NRC
. T. Magette, DNR
.g 8906260396 890614
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ATTACHMENT m RESPONSE TO NRC BULLETIN 89-01 i
" FAILURE OF WESTINGIlOUSE STEAM GENERATOR TUEE MECHANICAL PLUGS" i
The following information provides our response to NRC Bulletin 89-01. The items -are numbered to match the Actions Requested in the Bulletin.
1.
We have not installed any' Westinghouse mechani;:al plugs from the suspect heats
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J (3279,.3513, 3962 and 4523) in ' the Calvert Cliffs Unit 1 Steam Generators (SG).
However, Calvert Cliffs Unit 2 has 122 plugs from heat No. 3513 installed in its SGs. These plugs were installed on both the hot and cold leg tubes' in May 1987, i
We have verified that the information contained in References I and 2 of ~ NRC i
Bulletin 89-01 is correct for _ Calvert Cliffs Unit 2.
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2.
Calvert Cliffs Unit 2 is currently in a refueling outage and the actions required 1
under this item will be compleLd as described. below before the refueling octage
'j ends.
(a)
Steam ' Generator tube plug lifetimes have been estimated using ~ the~
methodology given in Reference 1: of NRC Bulletin 89-01. The. estimated lifetime for the plugs from heat 3513 ~ installed in Unit 2's SGs are as follows; 668 effective full power days (EFPD) for the hot leg plugs, and 3393 EFPD for the cold leg plugs. These plugs have been in place for I
approximately / 553 EFPD to date.
i (b)
We will repair or replace all the hot leg plugs from ' the affected heat prior to returning Unit 2 to service. The cold leg plugs will be - repaired and/or replaced before their estimated lifetimes expire.
(c)
We have reviewed the various repair methods available for ALARA considerations, We will use robotic manipulators for the repair or replacement of the SG plugs where possible.
(d)
Installation of Westinghouse tube plugs from heats 3279, 3513, 3962 and 4523 has been discontinued.
(e)
Westinghouse mechanical tube plugs removed from Calvert Cliffs' SGs regardless of heat number will be examined for the presence of primary water stress corrosion cracking on a sample basis for each heat. The results of these examinations will be provided to Westinghouse.
During our current Unit 2 refueling outage, we discovered three plugs, from heat No. 3513 on the cold leg side of No. 21 SG, with possible signs of leakage. We have thus far made attempts to remove two of these plugs for metallurgical examination using the Westinghouse i moval technique. Both attempts were unsuccessful The bottom threaded ' skirt of the first-plug sheared off. - This portion of the plug was. sent to Westinghouse for examination. The second removal attempt resulted in the plug threads being 1
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ATTACHMENT (1)
RESPONSE TO NRC BULLETIN ' 89-01
" FAILURE OF WESTINGilOUSE STEAM GENERATOR
. TUBE MECHANICAL PLUGS"
. stripped from the plug. We are presently making preparations to remove 'the third plug utilizing
.a. different vendor. If this plug is successfully
- removed, it will be sent. to Westinghouse for detailed metallurgical analysis.
3.
The SG tubes at Calvert Cliffs have full depth expansion. Therefore, this item does not apply.
4.
We have no " sentinel ~ related" mechanical plugs installed in the Calvert. Cliffs i
SGs. Therefore, this item does not apply.
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