ML20094P063
| ML20094P063 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 07/27/1984 |
| From: | Tucker H DUKE POWER CO. |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| NUDOCS 8408160517 | |
| Download: ML20094P063 (3) | |
Text
a.
t DumE Powsu GOMPANY P.O. DOX 03180 CHAMLOTTE. N.O. 28242
, Udly 270 984 Mr. James P. O'Reilly, Regional Administrator U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Re: Catawba Nuclear Station Units 1 and 2 Docket Nos. 50-413 and 50-414
Dear Mr. O'Reilly:
Pursuant to -10 CFR 50.55e, please find attached a Significant Deficiency Report No. SD 413-414/84-18.
Very truly yours,
<M /d Hal B. Tucker LTP/rbs Attachment cc: Director Mr. Robert Guild, Esq.
Office of Inspection and Enforcement Attorney-at-Law U. S. Nuclear Regulatory Commission P. O. Box 12097 Washington, D. C.
20555 Charleston, South Carolina 29412 NRC Resident.
Mr. Jesse L. Riley Catawba Nuclear Station Carolina Environmental Study Group 854 Henley Place Palmetto Alliance Charlotte, North Carolina 28207 21356 Devine Street Columbia, South Carolina 29205 INP0 Records Center Suite 1500 1100 Circle 75 Parkway Atlanta, Georgia 30339 SYYlCIAL CUI*y B408160517 840727 PDR ADOCK 05000413
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,.4 Catawba Nuclear Station laponrt Mer: SD 413-414/84-18 14ponrt Date: July 27, 1984 1%cility: Catawba Nuclear Station, Units 1&2 Identification of Deficiency: Transamerica Delaval Inc. furnished four diesels for the Catawba Nuclear Station with the possibility of residual stresses in the type AN piston skirts.
Initial Rmort:
On June 28, 1984, Mr Virgil Brownlee of the NRC Region II, Atlanta, Georgia office was notified of this deficiency by Mr L M Coggins, Mr J M Lines, Mr T L Utterback, and Mr R D Carroll of Duke Power Cmpany, Char-lotte, NC 28242.
Supplier and/or Cem:nLs:
Transamerica Delaval Inc. of Oakland, California, manufactured and supplied the type AN piston skirts that were initially in-stalled in the four Catawba diesels and are designated 1A, IB, 2A and 2B.
Description of Deficiency:
Four type AN piston skirts were found to have cracks adjacent to the piston pin bosses. Wese cracks are approximately vertical, and appear to initiate on the inside of the skirt where a circumferential rein-forcing rib intersects the piston pin boss. We largest crack, on diesel genera-tor 1A-cylinder 3L, penetrates the piston wall and is about 3 to 4 inches long on the outside. Rese cracks were visually located during an inspection, follow-ing and extended operational test of diesel generator 1A, and verified by dye penetrant and ultrasonic testing.
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Analysis of Safety Inplication:
An extensive failure analysis of the cracked
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. type AN ; piston iskirts is' now being performed by Failure Analysis Associates
-(FaAA)Jas _ part of :the 'IDI. Owners Group program. 'Ihis program includes L determi-nationt of residual and applied stresses, fractography, -and metallurgical evalua-
.tions.
t once the failure analysis is empleted, the' Analysis 'of. Safety, Inplication
~
issue can be addressai,'and this is expected to be by September 27, 1984.
Gamact.ive Action:
'Ihe cracked type AN piston skirts in the Catawba 1A diesel did not cause any operational problems, and 12 of the 16 skirts were free of cracks. However, all of the Unit 1 piston skirts will be replaced with improved design type AE skirts. 'Ihe AE skirts have been stress relieved and include improved design features such as a thicker reinforcing rib and better rib to piston boss intersection details. 'Ihese inprovenents are expected to adequately s
reduce stresses and the propensity for cracking in the area which experienced cracking at Catawba. In addition, the type AE skirts also incorporate the latest inprovements in the stud boss region, which has been a problem area in earlier piston designs at the skirt to head transition.
'Ihe decision regarding the replacement of the Unit 2 AN skirts with the AE skirts, will be made following the coupletion of the failure analysis by Failure Analysis Associates.
A final report addressing the Unit 2 piston skirts and the safety implication l
will subnitted by January 15, 1985. Unit 1 skirts are in place for diesel lA and diesel IB skirts will be in place by September 14, 1984.
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