ML19305C759
| ML19305C759 | |
| Person / Time | |
|---|---|
| Issue date: | 02/11/1980 |
| From: | Gammill W Office of Nuclear Reactor Regulation |
| To: | Jordan E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| References | |
| NUDOCS 8004080233 | |
| Download: ML19305C759 (2) | |
Text
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UNITED STATES NUCLEAR REGULATORY COMMISSION 3
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W ASHINGTON. D. C. 20555 g
o FEB 111960 MEMORANDUM FOR:
E. J. Jordan, Assistant Director for Technical Programs, I&E FROM:
W. Gamill, Acting Assistant Director for Operating Reactor Projects, DOR
SUBJECT:
IE DRAFT CIRCULAR - LOSS OF CONTROL ROOM ANNUNCIATORS DUE TO FAILED POWER SUPPLIES (RIS MODULAR DC CONVERTER AN-159)
We have reviewed the sub.i~.t draft and our coments are enclosed.
Ww=
W. Ga=ill, Acting Assistant Director for Operating Reactors Projects Division of Operating Reactors
Contact:
R. Senoll, X27162
Enclosure:
Coments 1Th&R-LLR 2
8004080
ENCLOSURE COMMENTS ON IE DRAFT CIRCULAR LOSS OF CONTROL ROOM ANNUNCIATORS DUE TO FAILED POWER SUPPLIES 1.
Description of Circumstances a.
An important fact that seems to have been forgotten is that Northeast Utilities has stated:
"During the evening of Friday, December 28, 1979, an anomally occuared in the Annunciator System in that certain alarm windows (one or two) began to flash without any audible alarm.
The flashing windows would extinguish (return to normal) upon depressing the annunciator reset pushbutton. This occurrence was not considered to require immediate attention and the Operators on shift submitted a maintenance request to the Instrument and Control Department."
Accordingly, the preceeding statement should be the first paragraph of the description of the circumstances.
b.
The second paragraph on page two states that the designed current is approximately 0.5 amps and that loads of up to two amps were observed.
It is recommended that, for clarity, the next-to-last line of this paracranh be modified by inserting the following phrase between "ote. ved" and the period, "because of the failure of some of the parai sel power supplies."
c.
The descriptions of the circumstances should also describe what is being done to reduce the likelihood of a reoccurrence.
Specifically, the licensee is checking the individual output voltages from each power supply on a weekly basis.
If future experience shows an acceptably low failure rate, the surveillance frequency will be reduced to bi-weekly.
2.
Recomended Action for Licensees' Consideration a.
The first reconsnendation should be that the licensees investigate any and all indications of improper alarm system operation, b.
Modify the reco:rrnendation that is presently number two to require that the checks of parallel power supplies be conducted in a manner such that individual power supply output. voltages are monitored.
.