ML20040C830

Informs of Inherent Problem Discovered w/4-wire Emergency Notification Sys Telephone Circuit. Lockup Occurs If Receiver Picked Up Before Circuit Light Goes Off After Use. Preventive Measures Should Be Used Until Equipment Modified

ML20040C830
Person / Time
Site:	Rancho Seco
Issue date:	01/21/1982
From:	Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
To:	Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT
References
TAC-46265, NUDOCS 8201290285
Download: ML20040C830 (2)

Text

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y JAN 211982 Docket No. 50-312 Sacramento Municipal Utility District P. O. Box 15830 4

g Sacramento, California 95813 RECElVED l

Attention: Mr. John J. Mattimoe f

JAN 281982w S2 Assistnat General Manager 3 n eunmm my L 5:Wgamn A

l Gentlemen:

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l An inherent problem has been discovered with the new (4 w e

Notification System (ENS) telephone circuit. The problem is descr bed below along with a simple method of prevention which should be used until telephone l

engineers complete equipment modifications.

After a call has be1n established (the originator of the call makes no difference) and terminated on the ENS circuit, the telephone circuit for the facility called will " lock up" if a receiver is picked up at that facility before the circuit light is off. This results in the facility not being able to call out on the ENS circuit and the NRC Headquarters not being able to call the facility. After " lock up" occurs a telephone serviceman will be required to disconnect and reconnect the phone circuit at the Headquarters switchgear.

For example:

The NRC Headquarters calls an operating power reactor plant for daily plant status. The reactor facility answers the call and gives the necessary information, after which, both parties hang up. The facility operator, realizing that he forgot to give some item of information quickly picks up the ENS phone in an effort to catch the NRC Headquarters

!efore Headquarters hangs up their phone. This type of action results in " lock up".

To prevent " lock up" from occurring, the facilities should ensure that a second call is not established within 20 seconds after the original call has tenninated. NRC Headquarters will be monitoring all ENS phone line indicators and will inform the facility when lock up occurs and provide a consnercial phone number to use to contact NRC Headquarters.

In addition, the NRC will contact the telephone company and initiate the necessary action to release the " lock up".

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$acramento flunicipal Utility District -

Telephone company engineers have found a solution to permanently correct the " lock up" problem. Until the "fix" can be applied, we will appreciate your cooperation in helping us minimize Ef15 phone circuit " lock up" so that the integrity of the Emergency flotification System will not be jeopardized.

Sincerely, uman sicao Et R.H.iEndeNdfi Regional Administrator bcc: DMB/ Document Control Desk (RIDS)

Distributed by RV:

State; Resident Inspector; RHE J. L. Crews; G. S. Spencer; H. E. Book; D. M. Sternberg; K. Scown l

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