ML20116C987
| ML20116C987 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 04/16/1985 |
| From: | Tramm T COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| 9980N, NUDOCS 8504290241 | |
| Download: ML20116C987 (2) | |
Text
.c
'N Comreonwealth Edison
- j) one First Nitionil Plaza, Chicago, Ilknois O 7 Address Reply to: Post Office Box 767
(,/ Chicago, Illinois 60690 A'pril 16, 1985 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
Byron Generating Station Units 1 and 2 Seismic Qualification of Equipment NRC Docket Nos. 50-454 and 50-455-References (a):
October 16, 1984 letter from T. R.
Tramm to H. R. Denton (b):
March 5, 1985 letter from T. R. Tramm to H. R. Denton (c):
March 8, 1985 letter from B. J.
Youngblood to D. L. Farrar
Dear Mr. Denton:
This letter _provides additional information regarding the justification for interim operation of certain Westinghouse 7300 series instrumentation at Byron Station.
This letter is provided at the request of the NRC Staff to document information provided by telephone.
References (a) and (b) documented the justification for interim use of NTC cards in the 7300 series process instrumentation.
Seismic qualification testing disclosed that these cards contained a mercury-wetted relay with contacts which could bounce during an l
In certain applications, such contact bounce could inhibit the function of the reactor protection system.
In recent attempts to find an acceptable replacement relay, Westinghouse has confirmed that the rest of the NTC card functioned properly during seismic testing.
The mercury-wetted relay was the only component which could not be qualified.
Until seismically qualified NTC cards are available, the
. cards normally used have been modified by the installation of jumper wires in place of the relay.
This modification was done according to Wastinghouse FCN CACM 10756.
The jumper wires were soldered in placb by qualified instrumentation maintenance personnel.
There is 4
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H. R. Denton April 16, 1985 no concern that a jumper wire would separate from a card during an earthquake.
Please direct further questions regarding this matter to this office.
One signed original and fifteen copies of this letter are provided for NRC review.
Very truly yours, f}?ib&t.n+w T. R.
Tramm Nuclear Licensing Administrator 1m cc:
Byron Resident Inspector 9980N l
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