ML20236F835

Ro:On 870814,governor Hunting Observed Following Diesel Generator Startup.Caused by Intermittent Operation of 4EX3 Relay.Diesel Generator 1B Will Remain on Monthly Testing Schedule Per Tech Spec 4.8.1.1.2

ML20236F835
Person / Time
Site:	Byron
Issue date:	10/27/1987
From:	Querio R COMMONWEALTH EDISON CO.
To:	Davis A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
BYRON-87-1017, NUDOCS 8711020312
Download: ML20236F835 (2)

Text

,_

? ,<*

J/~.m , .N C:mmonw2lth Edison' ON. a

'" z: 1 Byron Nuclear Stition ' .  ;

J

-l

\ Q7 4450 North Garrnan Church Rold j '

pg

, .(  : Byron, Illinois 61010 :

,,, I WW 1 l &

October 27,' 1987' / 8' ~

i

-., J l

LTR:' BYRON 87-1017 f2L /J

' i Mr.'A. Bert Davis Regional, Administrator

' Region.3 .

1 799 Roosevelt Poad l Glen-Ellyn,-Illinois 60137 l

'i i

Dear Sir:

This report is . submitted in accordance with Byron Station Unit 1 Operating y

-License NPF-37 Appendix A', Technical Specification 4.8.1.1.3, reporting of j Diesel Generator Failures, j

This report addresses one valid t'st e and failure experienced on the 1B Diesel

' Generator. : The criteria t.o d:termine valid tests and failures is in accordance with Section C.2.e of Regulatory Guide 1.108.

On August 14,'1987, the IB diesel generator was started per the quarterly

-slave relay surveillance, IBOS 3.2.1-816. Following the start, the system test engineer noticed that the. governor was hunting. The diesel was then taken to manual test mode and again, governor hunting was observed. The IB diesel generator was shutdown at 1505 and Limiting Condition for Operation

-Action Requirement (LCOAR) 8.1.1-la was entered., Following two maintenance ~

runs, it.was decidad to replace the 4EX3 relay. The 4EX3 relay provides an  ;

electric signal to the engine electronic governor for spced droop mode during t i

. testing and for isochronous mode during emergency operation. Intermittent i operation of this relay can cause the governor to' loose its speed reference, I which in turn'causes the instability. Following installation of the new 4EX3 j relay the diesel was started for a maintenance run. All parameters were normal. At 2036 on 8/14/87, the IB diesel generator started per the monthly operability surveillance, IBOS 8.1..l.2.a-2. At 2356 the surveillance was successfully completed and the LCOAR was exited.

The root cause for this event was intermittent operation of the 4EX3 rel: (.

Byron Station is currently investigating the possibility of replacing the relay with a more reliable relay. This investigation will be tracked by Action Item Record (AIR 454-512-87-0257).

[0CT 2 91987 M

9

• • i?E E k iC ,

M *y 1

I

N ' ,

, , .~. ~

.i' i* 4 i yt. ,

tes >

^ -

ja -

Byron 87-1017 :

JT ..s

.Page'2-L s.

> 4

.:p ,

.; . 1 The s1B 'dieself generatdr 'was ' inoperable - for .8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> 'and 51' minutes as a resulti?

-of~thisTevent. This--failure was the.first-failure during.the'last twenty.

' valid tests,- therefore the::1B diesel generator willi remain on a monvaly

testing' schedule per.. Table'4,8-1.of Technical Specification 4'8.1'.1.2.

i;

) -

1

R..E. Querio; . .

. Station Manager-  ;[

Byron Nuclear Power Station-REQ /MMR/JC/bf (0036z). -4

+ ;cc: P. Brochman, NRC Senior Resident' Inspector

U.S. NRC Document Control Desk, Washington, D.C.

'INPO Record Centier'.

CECO Distribution List-R. : Willia:as .

-J. Cook i~ .

'I i

l r \

i

~!

t i

1:

f _;

h-m______E__i. _ _ _ _ _ _ _ . _ _