ML20074A147

Final Deficiency Rept Re Failure of Rocker Arm Assembly Holddown Capscrew on Transamerica Delaval Emergency Standby Diesel Generators.Initially Reported on 830330.Capscrews Replaced.Changeouts Completed Per E&Dcr F-45462

ML20074A147
Person / Time
Site:	Shoreham File:Long Island Lighting Company icon.png
Issue date:	05/04/1983
From:	James Smith LONG ISLAND LIGHTING CO.
To:	Allan J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
10CFR-50.55E, SNRC-873, SNRC-883, NUDOCS 8305120328
Download: ML20074A147 (4)

Text

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, fig LONG ISLAND LIGHTING COM PANY

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17 5 EAST OLO COUNTRY ROAD

• H IC K SVI LLE, NEW YORK 11809 Direct Dial Number May 4, 1983 SNRC-873 Mr. James M. A .an Acting Regional Administrator Office of Inspection & Enforcement, Region 1 U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406 Long Island Lighting Company Shoreham Nuclear Power Station - Unit 1 Docket No. 50-322

Dear Mr. Allan:

On March 30, 1983, in accordance with 10CFR50.55 (e) , we reported verbally to Region 1 a potential deficiency concerning the failure of a rocker arm assembly holddown capscrew on the Shoreham Emergency Standby Diesel Generators. This letter serves as our 30-day written report on this potential deficiency.

Description of the Potential Deficiency The three diesel generators which are affected were manufactured by the Transamerica Delaval Company of Oakland, California. These diesel generators, 1R43*G-101, 1R43*G-102, and 1R43*G-103, in the Diesel Emergency Power System are designed to provide standby emergency power for multiple plant safety related systems.

The problem was discovered during testing of Diesel Generator 103 (lR43*G-103) when a sudden change in the sound of the running engine was detected by the operator. The operator shut down the engine and an attempt was made to determine the source of the noise. Upon removing the valve cover of the #1 cylinder, it was discovered that the intermediate-intake rocker arm assembly hold-down capscrew had failed.

Subsequent to the failure, a preliminary field inspection of the failed capscrew was performed by a LILCO metallurgy specialist in conjunction with an onsite engineering representative of 8305120328 830504 PDR ADDCK 05000322 S PDR L

SNRC-873 May 4, 1983 Page 2 Transamerica Delaval. On the basis of the preliminary field in-spection, ic appeared that the failure was due to fatigue lotding with cracking found to be initiated at the bolt thread root. As a result of the findings of this field inspection, magnetic particle inspection was conducted on all rocker arm assembly holddown cap-screwa and linear indications were noted on 46 of them. The failed capscrew and its associated rocker arm assembly and sub-cover were then returned in their "as found" condition to Transamerica Delaval for a formal failure analysis, as were the 46 capscrews with linear indications. Although the Transamerica Delaval fail-ure analysis report has not yet been received, verbal discussions e

with Transamerica Delaval have indicated that their examination results to date have not revealed significant indications on the balance of the capscrews which would have been indicative of incipient failures.

Corrective Action & Action to Prevent Reoccurrence Although Transamerica Delaval has advised, as described above, that the capscrew failure was an isolated instance, LILCO has elected to change out all original capscrews in this application and replace them with a modified Transamerica Delaval, design cap-screw with improved fatigue characteristics.

This redesign is based on a rocker shaft bolt developed for Delaval's HV-A series engine. The modified rocker shaft bolts are designed to reduce fatigue sensitivity in the bolt by transferring the regions of highest stress away from the stress concentrations in the root of the threads and reducing the cyclic loading on the bolt. The reduction in cyclic loading is achieved by decreasing the diameter of the shank, thereby increasing the elongation / stress relationship of the bolt. This effectively transfers more of the cyclic load to the stiffer rocker arm shaft, which is loaded in compression.

The rocker arm capscrew changeouts have been completed via E&DCR F-45462, therefore, our corrective action has been completed. Any further replacements for these capscrews will be of the improved design.

e SNRC-873 May 4, 1983 Page 3 If you have any questions relative to this matter, please do not hesitate to contact us.

Very truly yours, J. L. Smith Manager, Special Projects Shoreham Nuclear Power Station WMJ/ laws 3 cc: Mr. Richard DeYoung, Director NRC Office of Inspection & Enforceaent Division of Reactor Operating Inspection Washington, D.C. 20555 Mr. J. Higgins, Site NRC All Parties - Attachment i n.

ATTACl! MENT 1 em

-1,awrence Brenner, Esq. IIerbert 11. Brosin, Esq.

Administrative Judge Lawrence Coe Lanpher, Esq.

Atomic Safety and Licensing Karla J. Letsche, Esq.

Board Panel Kirkpatrick, Lockhart, Ilill U.S. Nuclear Regulatory Cc.amission Christopher & Phillips Washington, D.C. 20555 8th Floor 1900 M Street, N.W.

Dr. Peter A. Morris Washington, D.C. 20036 Administrative Judge Atomic Safety and Licensing Mr. Marc W. Goldsmith Board Panel Energy Roscarch Group U.S. Nuclear Regulatory Commission 4001 Totten Pond Road Washington, D.C. 20555 Waltham, Massachusetts 02154 Dr. James H. Carpenter MllB Technical Associates Administrative Judge i 1723 IIamilton Avenue Atomic Safety and Licensing Suite K Board Panel San Jose, California 95125 U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Stephen B. Latham, Esq.

Twomey, Latham & Shea Daniel F. Brown, Esq 33 West Second Street Attorney P.O. Box 398 Atomic Safety and Licensing Riverhead, New York 11901 S Board Panel s,J.S. Nuclear Regulatory Commission Ralph Shapiro, Esq.

Washington, D.C. 20555 '

Cammer and shapiro, P.C.

9 East 40th Street Bernard M. Bordonick, Esq. New York, New York 10016 David A. Repka, Esq.

U.S. Nuclear Regulatory Commission Matthew J. Kelly, Esq.

Washington, D.C. 20555 State of New York Department of Public Service James Dougherty Three Empirc State Plaza 3045 Porter Street Albany, New York 12223 Washington, D.C. 20008 i

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