ML20084E063

AO 50-237/75-16:on 750317,diesel Generator Failed to Start. Caused by Failure of Pinion Gears to Engage Ring Gear. Problem Appears to Be in Gear Mfg

ML20084E063
Person / Time
Site:	Dresden
Issue date:	03/27/1975
From:	Stephenson B COMMONWEALTH EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
195-75, 3438, AO-50-237-75-16, NUDOCS 8304140045
Download: ML20084E063 (2)

Text

r ,

I Crmm:nwealth Edis:n

[N l'Q- {, O'de F( llational Plata. Chicago, Illinois sC// XddrE.jeply to P55i6fEce BE757

' vf'

-~

Chicago, Ilknois 60S90 V

1 BBS Ltr. #195-75 Dresden Nuclear Power Station , l R. R. #1 .e ' <

Morris, Illinois 60450 's March 27, 1975  :'

~ '

Mr. James G. Koppler, Regional Director ,

Directorato of Regulatory Operation-Region III i .'? -

U. S. Nuclear Regulatory Co.: mission 799 Roocovelt Road Glen Ellyn, Illinois 60137

SUBJECT:

REPORT O? fPl!ORMAL OCCURPJECE PER SECTION 6.6.A OF THE TECETICAL SPTIFICATIO:!S FAILURE OF UilIT 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: P. Johnson,1430 hours0.0166 days <br />0.397 hours <br />0.00236 weeks <br />5.44115e-4 months <br /> on March 18, 1975 Telegram: J. Koppler, 1430 hours0.0166 days <br />0.397 hours <br />0.00236 weeks <br />5.44115e-4 months <br /> on March 18, 1975

3) Drawing Number M173 Ecport Number 50-237/1975-16 Report Dates March 27, 1975 Occurrence Dates March 17, 1975 Facility: Dresden Nuclear Power Station, Morris, Illinois IDEt7PIPICATION OF OCCURRENCE Unit 2 was in the cold shutdown mode during an extended refueling outage.

The calibration of various pressure gauges had just been completed when the diesel generator failed to start.

DESCRIPPION OP OCCURRECE On March 17, 1975 at approximately 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br />, the Unit 2 diesel generator failed to start. The operator thcn struck the air start solenoid and the diesel conerator started.

lt$ 0Il38 pmmm, PDR i _ _ ___ . . _ _ . - . .

Mr. James G. Kappler March 27,.1975..

DESIGNATION OF APPARa77 CAUSE OP OCCURRE;CE (Fabrication Error)

The mintenance performed just prior to the failure was not related in any way to the starting problem. The air start solenoid also did not appear to be the problem but was disassembled, cleaned and reinstalled. The diesel generator was then started several times and some additional failures were experienced. The problem was traced to the air start motors where it was found that the pinion gears were not properly engaging the ring gear.

Another problem with the diesel generator bocaraevident when it failed to come up to voltsge during some of the test runs. This matter will be discussed in subsequent report number 50-237/1975-18.

ANAINSIS OF OCCURRDiCE Public health and safety were not jeopardized due to this occurrence because the redundant Unit 2/3 diesel generator was operable and could have been employed if necessary.

CORRECTIVE ACTION

• The unit 2 diesel generator was imediately taken out of service and an investiga-tion began the morning of March 18, 1975. A series of startup tests were conduct-ed which indicated that the air start motors may have been the problem. The two air start notors were then replaced ani cent back to the factory for inspec-tion to determine the exact cause of failure. Based on the results of a report to be written by the factory, additional corrective action may be initiated.

FAILURE DATA d Many of the previous starting problems encountered with the diesel generators at Dresden have been attributed to faulty air start systems. These problems were primarily due to excess airt and oil in the system'or solenoid valve failure. Periodic cleaning and replacement of the various components in a the air system has been effective in reducing these problems. Worn pinion

gears have caused this type of failure in the past, but since the air start

{ motors involved here were relatively new (installed January 18, 1975) it would appear the problem was in manufacturing.

• The unit 2 diesel generator was manufactured by Electro-motive division, General Motors Corporation. It is rated at 2500kw, 4160 y and 900 REi.

The air start motors were manufactured by Ingersoll-Rand. .

. B. Stephenson Superintendent BBS smp Pilo /MRC N"4"-wa- - ___ m __ _ --