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 rueucununts TELEPHONE 717 944.4.M1 POSTOFf ICE GOX 480 M100LETOWN.PENNSYt.VANIA T7057 July 22,1975 J u b 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

- were " picked up." The Diesel Generator was operating at approxicately GC0 J7M 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 prevent the breaker from closing. For this reason. it was detarminea that the A Diesel Generator was operable.

The l The relay was removed from service and replaced with another relay. The suspect relay was tested and fcand to operate at the correct f I functioned correctly.

1 Additional investigation will be snade to deterraine the cause for the relay not being in the correct state.

Very truly yours, i

W J.J. Colitz

'l unit i soperintenden i

0910240 /  !

f h