ML20077J490

Advises of Diesel Generator Condition in Light of Pending Contention.Wl Mchugh to Nm Rudikoff Describing Cracks in Bridges Encl

ML20077J490
Person / Time
Site:	Shoreham File:Long Island Lighting Company icon.png
Issue date:	08/10/1983
From:	Reveley W HUNTON & WILLIAMS, LONG ISLAND LIGHTING CO.
To:	Brenner L, Ferguson G, Morris P Atomic Safety and Licensing Board Panel
References
ISSUANCES-OL, NUDOCS 8308160452
Download: ML20077J490 (5)

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6 7 5 50~3B.Eot I 000KETED Huwrow 6e WILLIAMS USNRC 707 EAsf MAIN sTRECT P. o. Box 1535 O 0 6 v .ustoimo DCPEMOND, VIMI.NIA 23 212 a T3 AW 15. m o.e.on.%.aao n o. .oa so. a mattion, NoRTM Camouma av.oa ******'*"*" "'** **

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m .o=3... 00CKEIING BRANC9tc& SER.vl:.24566.000003 NOIFoLR, vimof Nia an.te co .a.... ' a c' *' "* * ' '.. 8 3 5 9 August 10, 1983 Lawrence Brenner Dr. Peter A. Morris Administrative Judge Administrative Judge Atomic Safety and Licensing Atomic Safety and Licensing Board Panel Board Panel U.S. Nuclear Regulatory U.S. Nuclear Regulatory Commission Commission Washington, D.C. 20555 Washington, D.C. 20555 Dr. George A. Ferguson Administrative Judge Atomic Safety and Licensing Board Panel School of Engineering Howard University 2300 6 th Street, N.W.

Washington, D.C. 20059

Dear Judges:

I write to advise the Board of a condit. ion observed recently on the Shoreham diesel generators. LILCO and Delaval have concluded that this condition is not reportable under 10 CFR S 50.55 (e) and does not present a safety concern or affect the operability of the diesels. Nevertheless, and even though the matter is not within the scope of the pending contention, LILCO is advising the Board of the matter in light of the pending contention. i Attached is a copy of'.a letter dated August 3,19 83 from William Lanny McHugh to.Neal M. Rudikoff describing this condition and assessing I'ts sign'ificance. In essence, LILCO personnel, in the course of replacing the old cylinder heads with the new ones, observed and reported cracks in the web of the bridge between the two sides of the subcover assembly at i

8308160452 B30810 PDR ADOCK 05000322 '

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I llUNTON & WILLIAMS

, a Lawrence Brenner Dr. Peter A. Morris Dr. George A. Ferguson August 10, 1983 Page 2 the fuel injector indentation. These cracks were observed in 5 of the 24 bridges. As the attached letter from Delaval reflects ,

the purposes served by the bridge are such that the cracks do not affect the function or operability of the diesels. Indeed, as the letter also reflects, the engine can operate and meet its requirements and functions even if the bridge is entirely removed.

Respectfully, V

79/869 W. T y Re eley, III Attachment cc: All Parties l

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1.ona Island Lightinu Cc:cpany Shorohotn Nuclear Power Station I

p. O. Box 610 l 1; 192 l Wading itiver, New Yozk Attentient.,,,y C leal M. Itudikoff Subirsti Diosal Generators TDI S/N 74010-12 Subcover, Cylinder lland P/N 1h 2780 Itoforonce: Lolt 1541 ,-

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Ouring the curront planned cylinder head change, -

crnoks were observed in fivo of the cylinder hood sub-covors. These cracka oxtonded into the web uridging the two sidwu of thu subcover et the fuel in.lootor indentation, originating at the trunwition between the web und the boss for the internal subcover hold down bolt on the vertical piene through crankshaft centurlina.

Thora are two different subcover casting reviulons on the St1PS Diesels. The original or old Mtylu CQSting had a flat unreinforcod wob, approxiniatuly 5/16 inch thick (nominol), bridging the two niden ut t.tm subcover.

The new style costing had a web 1/2 inch thiok (nominul) with two 1/2 3neh ribs. This change wac inade to the costings in 1974. The tuo casting revisions uore considered * ,

functionally idontical and interchangonble, hence the LILCO enoines had 14 old ,ctyle subcover castings, and 10 new style castings inutulled.

The crochs all occurred on old style nuncovers uith unreinforced webs. Tho inost extensivo crack, which l

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W Mr. Neal M. Rud2kott August 4, 1983 oxtonded completely through the bridge web neparating the two sides of the subcover, occurrod on the thinnest .

subcover web (3/16 inch thick, from DG-102 cylinder 2) .

. Three of the seven 1/4 inch thick webs were cracked -

and one of the three webu more than 1/4 inch thick had a small crack. None of the ton how stylo reinforced bridge webs were cracked.

The functions of the subcover bridge are:

. (1) to provido additional c]emping forces to r.he

- gasitet between the subcover and head at .

the base of the fuel injoctor indantation, and .

.. . .- (2)'to provide rigidity und provent distortion .

- - of the nubcover castino during the foundry's

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- core shukoout and coolina operation und for "

machining of the subcover. e

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7- The. bridge does not' provide any. additional support for ,

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the rocker shafts. .

f These' cracks ofton' originate from Hhrink Cracks in f,.' -

the easting. and ur.o..propaga,%ed,':through .cyc.lio J.onding ot* ,

'" the subcovor bridge veb resulting from ongine firing prosauro. The cracks propagate duwn und across the sub-

. cover at approximately a ,45 , angle until they reach the *

,,, . heavy wall.of the injector' indentation. They then propagate down.'the web' alona the subcover wall to the base of the

'., web. At this point, the stresses nre relieved and no

. addftionoL" cracking occura. ' TDI's provious experience with

. cracked old; style subcovers hau. demonstrated that the

. clamping forces providud' by the subcover wall nione, without .

q are. sufficient to prevent lobo oi!

'.:y , the bridge'. web support, leaks from the pool of" oil at the top of the cylindor head. ,

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.0 S This has been verified at tho SNPS by the subcover un .

T cylindor 2.of UG102 which was cracked completely through the bridgo web, ,thereby eliminuting any possible nupport to tho

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, fuel injector indentation from the opposito wall of the '

subcover, and was not leaking lubu oil around the fuci --

U* Injector indentation. .

Based on the facts that the bridge web does not provide addit;1onal support for the rocker erm shaf ts, that tho  :

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Mr. Noni ti. Rudikoff .

August 4, 1983 additional clamping force at the fuel injector; indentation-is not required for proper gaskot sealing. and that once tho stresses uru relieved by the separation of t.he subcover -

sides no additional degradution of the subcover occura; the structural support provided by the bridge web .is not required for Diesel 6peration. Thersfore, the cracked subcovera present: no safety or operability problems. The ongines may be run with crackod subcover bridge wobs, or the subcover bridgo web Iws y be removed in its entirety. .

If you huvo any further questions regarding this

. Inntter, please do not healtht.e to contact me.

, . Vory truly yours, ,

ajuAm *# '

I'*'[. e Wm. Lunny McHugh Engineer, Customur Sorvice

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