ML20084D141

AO 50-237/75-39:on 750612,diesel Generator Failed to Start During Surveillance Run.Cause Not Known.Suitable Action to Be Taken When Cause Determined

ML20084D141
Person / Time
Site:	Dresden
Issue date:	06/18/1975
From:	Stephenson B COMMONWEALTH EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20084D121	List: ML20084D119 ML20084D141
References
378-75, 8883, AO-50-237-75-39, NUDOCS 8304080479
Download: ML20084D141 (3)

Text

s Commonwe:lth Edison I. One Firs;^$ional Plata. Chicago, Illinois

. * * . , ~

( / AddrEsk jly to Post Office Box 767 x )

(_ / Chicago. tilinois 60390 BBS Ltr. #378-75 Dresden Nuclear Power Station R. R. #1 Morris, Illinois 60450 T l June 18, 1975 gf' ~ ']?N '

/O.9y.. ,

w to . .

4, Mr. James G. Keppler, Regional Director  ; c,- .T .

Directorate of Reguletory Operation-Region III iQ p, .

U. S. Nuclear Regulatory Co:anission {-"., ~ *M v-799 Roosevelt Road T p. , s Glen Ellyn, Illinois 60137 N' 9x/ly~.

s SUBJET: REPORT OF AB';0RMAL OCCURRENCE PER SECTION 6.6.A 0F THE'TERNICAL SPECIFICATIONS FAILURE OF THE UNIT-2 DIESEL GENERATOR TO START

References:

1) Regulatory Guide 1.16 Rev. 1 Appendix A

2) Notification of Region III of U. S. Nuclear Regulatory Comission Telephone: Mr. Knopf, 1700 hours0.0197 days <br />0.472 hours <br />0.00281 weeks <br />6.4685e-4 months <br /> on June 12, 1975 Telegram: Mr. J. Keppler, 1245 hours0.0144 days <br />0.346 hours <br />0.00206 weeks <br />4.737225e-4 months <br /> on June 13, 1975

3) Drawing Number M173

4) Letter from B. B. Stephenson to J. G. Keppler on June 13, 1975

~

i (Report No. 50-237/1975-37) i Report Number 50-237/1973-39 j Report Date: June 18, 1975 Occurrence Date: June 12, 1975 Facility: Dresden Nuclear Power Station, Morris, Illinois IDD4TIFICATION OF OCCURRB;CE The Unit-2 diesel generator failed to start during a surveillance run.

CONDWIONS PRIOR TO OCCURRDICE Unit-2 was at a steady-state power level of 1127 MWt and 346 MWe, f

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• frv',e I 4 aco3 0479 760413 S DCK 05000237 PDR COPY SIMl'ItEGION_ _

Mr. Jan'a G, K:ppl q Juns 18, 1975 O p) 1 DESCRIPTION OF OCCURRD;CE At approximately 0119 hours0.00138 days <br />0.0331 hours <br />1.967593e-4 weeks <br />4.52795e-5 months <br /> on June 12, 1975 ths Unit-2 diesel generator failed to start twice in the four times it was tested.

DESIGNATION OF APPARENT CAUSE OF OCCURRDiCE The exact cause for the Unit-2 diesel generator starting failures is not known at this time. Several attempts were made to locate.the source of the failures with a factory representative on hand. Problems have been encountered with the air start motors; consequently, they have been closely observed during numerous start-up tests. .

One possible cause of failure is the time delay' relay (TD-2) which trips the diesel if it has not attained 200 rpn within 15 seconds. Although this relay has functioned properly during testing, an intermittent failure could account for l

the starting problems. _

Another problem with the diesel has been high crankcase pressure trips during testing. A' factory representative has attributed this high pressure to the nu=erous starts and low-load runs conducted while attempting to locate the starting problems. Loose gaskets on the top deck covers were found to be causing the trips. Although high crankcase pressure is not a reportable incident, there is no doubt that excessive starting of the. diesel generator.should be avoided.

In any event, the proper personnel will be on hand during normal surveillance rune to evaluate any further problems.

ANALYSIE OF OCCURREJCE The Unit 2/3 diesel generator, LPCI, and Core Spray were immediately determined to be operable as required in the Technical Specifications. The health and safety of the public were not jeopardized by this occurrence.

CORREX'TIVE ACTION This incident is a recurrence of a previously reported problem (Report No.

50-237/1975-37) and is still under investigation.

When the cause has been determined, suitable action will be taken and a follow-up letter sutraitted.

FAILURE DATA The Unit-2 diesel generator has had several recent starting failures of a similar nature. Previous failures occurred on June 4, 1975 (Report No. 50-237/1975-37),

April 15, 1975 (Report No. 50-237/1975-26), and on March 17, 1975 (Report No.

50-237/1975-16).

• - n . Jadas G; Keppi Juna 20, 1975

- The diesel gene.ator was manufactured by Electro-Fotive Division, General Votors Corporation. It is rated at 2500 KW, 4160 V and 900 arm.

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B. G. Itephenson Superintendent BBS:JE4:s=p .

File /NRC e

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