ML20099C778

Final Significant Deficiency Repts SD-413/84-18 & SD-414/84-18 Re Four Tdi Diesels W/Possible Residual Stresses in Type an Piston Skirts.Initially Reported on 840628.Unit 1 Piston Skirts Replaced

ML20099C778
Person / Time
Site:	Catawba
Issue date:	09/27/1984
From:	Tucker H DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
SD-413-84-18, SD-414-84-18, NUDOCS 8411200064
Download: ML20099C778 (3)

Text

N V,. _4 ,

.3 p.

DUKE POWER GOMPANY ~ l

. P.O.190X 33189 l CHAllLOTTE, N.C. 28242 l

- HAL B. TUCKER - ' ygtgpuoy, N 0c7 2 ""*""~*"

- ;;--, , _ e l: 2n-September 27, 1984 Mr. James P. O'Reilly, Regiorm1 Administrator U. S. Nuclear Regulatory Commission Regiort II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30303 Re: Catawba Nuclear Station Units 1 and 2 Docket Nos. 50-413 and 50-414 Significant Defis iency 413-414/84-18

Dear Mr. 0'Reilly:

Please find attached a final report on the subject Deficiency which was

~

identified in my letter of July 27, 1984. All corrective action has been completed for the Unit 1 diesels.

Very truly yours, Hal B. Tucker LTP/mjf 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 Inspector Mr. Jesse L. Riley i Catawba Nuclear Station Carolina Environmental Study Group 854 Henley Place Palmetto Alliance Charlotte, North Carolina 28207 2135 Devine Street Columbia, South Carolina 29205 INPO Records Center Suite 1500 1100 circle 75 Parkway Atlanta, Georgia 30339 1ho O s OFFICIAL copy SE Rf NI ._ _ _

=. -

a .. .

.o:

Final Report Catawba Nuclear Station-IkYnrt Number: SD 413-414/84-18 Report Date: September 27, 1984 Facility: 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 Report: On June 28, 1984, Mr Virgil Brownlee of the NRC Region II, At-lanta, Georgia office was notified of this deficiency by Mr L M Coggins, Mr e M Lines, Mr T L Utterback, and Mr R D Carroll of Duke Power Cmpany, Charlotte, NC 28242.

Supplier and/or Quponents: Transamerica Delaval Inc. of Q1kland, California, manufactured and supplied the type AN piston skirts that were initially installed in the four Catawba diesels and are designated 1A, 1B, 2A and 2B.

W Description of Deficiency: Four type AN piston skirts' were found to have cracks adjacent to the piston pin bosses. These cracks are approximately vertical, and appear to initiate on the inside of the skirt where a circumferential reinforcing rib intersects the piston pin boss. We largest crack, on diesel generator 1A-cylinder 3L, penetrates the piston wall and is about 3 to 4 inches long on the outside. Wese cracks were visually located during an inspection, following an extended operational test of diesel generator 1A, and verified by dye penetrant

n

-(*

4 '

\ .PageL2

'and ultrasonic testing.

p

- Analysis $f' Safety Implication: We cracking of ~ the AN type piston skirt was attributed' to high cycle fatigue. %e Catawba unit 1 ' diesels _ operated approxi-mately 800 hours0.00926 days <br />0.222 hours <br />0.00132 weeks <br />3.044e-4 months <br /> without the operability of the diesel being cmprmised. .Were-fore, it is reasonable to expect continued operation _ of the diesel, using an AN type piston skirt, without a piston failure. However, since 4 AN type piston skirts. cracked, this situation is evaluated to be a potentially generic problem.

As a result, the AN type piston skirts in the Catawba unit 1 diesels have been replaced with the inproved AE type piston skirt, .and the Catawba unit 2 diesels are expected to have the AE type piston skirts installed by August, 1985.

CbuccLive Action: The . cracked type AN piston skirts in the Catawba IA diesel did - not cause any operational probims, and 12 of the 16 skirts were free of cracks. However, all' of the unit 1 piston skirts have been replaced with improved i

design AE type skirts. We AE skirts have been stress relieved and include im-

, proved design features such as a thicker reinforcing rib and better rib to' piston 1

/

j boss intersection details. Wese improvements are expected to adequately reduce stresses and the propensity for cracking in the area which experienced cracking l .at Catawba. In addition, the type AE skirts also incorporate the latest improve-ments in the stud boss region, which has been a probim area in earlier piston designs at the skirt to head transition.

We Catawba unit 2 diesels are expected to have the type AE piston skirts installed l by August, 1985.

i

. - - c- - - , .- , . . .

,-+--,,-,-,,3-.--.

- - , - ,,r,m..-,--.-r-. , - , , , - - - - - - - . - . . , - , - - - , - . . , - , . , . - - - , - , - - ,