ML19210A199

Abnormal Occurrence 75-25:on 750722,three Frequency Relays to Steam Generator a Found in Dropped Out State.Relays Replaced & Returned to Svc.Cause of Failure Yet to Be Determined

ML19210A199
Person / Time
Site:	Three Mile Island
Issue date:	07/22/1975
From:	Colitz J METROPOLITAN EDISON CO.
To:
Shared Package
ML19210A196	List: ML19210A195 ML19210A199
References
NUDOCS 7910240919
Download: ML19210A199 (1)

Text

.....'=*g"~N ,--. i L'"~, METC' OLITAN EDlSON COMPANY suessoraavor aweast rueucununtscomaAncu. -TELEPHONE 717 944.4.M1 M100LETOWN.PENNSYt.VANIA T7057 POSTOFf ICE GOX 480 July 22,1975 b J u Mr. J.P. O'Reilly, Director Directorate of Regulatory Region I 631 Park Avenue King of Prussia. Pa.

19406 Operating License DPR-50 Eacket 50-289

Subject:

Abnorinal Occurrence No A0 75-25

Dear Mr. O'Reilly:

This telegram is to confim the conversatibn between ftr. A.N; Fasano (Decion J-NRC) and J.J. Colitz (TMI Unit 1 Superintendent) at 0830 hours0.00961 days <br />0.231 hours <br />0.00137 weeks <br />3.15815e-4 months <br /> 22 July 1975.

The fo11cwing report is submitted in accordance with paragraph 6.7.2.a.4 (page 6-11) of the Technical Specifications.

.On 21 July. ene of the three frequency relays for the A Diesel Generator was found to be in the " dropped out" state while the Cther two free,cency relays The Diesel Generator was operating at approxicately GC0 J7M were " picked up." The Diesel (60 cycles /second) at the time this relay condition was observed.

-Generator had been started and loaded for a short period cf thm for testing.

The frequency relays serve as an interlock which only allows the breiker to close when the Utesc1 C-enerator is up to speed. The frequency reicys are connected in a two-out-of-three logic thus any one relay failuro *4111 not For this reason. it was detarminea that prevent the breaker from closing.

the A Diesel Generator was operable.

ThelThe relay was removed from service and replaced with another relay.

The suspect relay was tested and fcand to operate at the correct frequency. diesel was successfully operated wit *a the replacemant relay and the relay I functioned correctly.

Additional investigation will be snade to deterraine the cause for the relay

, 1'not being in the correct state.

Very truly yours, i W.J.J. Colitz unit i soperintenden

'l i 0910240/!f h