ML20210L475
| ML20210L475 | |
| Person / Time | |
|---|---|
| Issue date: | 03/14/1986 |
| From: | Leeds E NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| To: | Rubin S NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| Shared Package | |
| ML20210L468 | List: |
| References | |
| NUDOCS 8604290348 | |
| Download: ML20210L475 (1) | |
Text
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MEMORANDUM FOR: Stuart D. Rubin, Acting Chief Reactor Operations Analysis Branch Office for Analysis and Evaluation of Operational Data FROM: Eric J. Leeds, Reactor Systems Engineer Reactor Systems Section 1 Reactor Operations Analysis Branch Office for Analysis and Evaluation of Operational Data
SUBJECT:
SPURIOUS SYSTEM ISOLATIONS CAUSED BY THE PANALARM MODEL 86 THERM 0 COUPLE MONITOR The enclosed engineering evaluation report is forwarded for your information and consideration. The study found that system isolations of various BWRs were coninonly caused by spurious trips of the Model 86 thermocouple monitor manufactured by the Panalarm Division of the Ametek Company. The study found that the elevated sensitivity of the thermocouple monitor makes the instrument highly susceptible to spurious trips caused by any momentary disturbance to its electrical circuitry. The spurious system isolations caused by the instru-ments are undesirable because of the potentially adverse impacts on system reliability, isolation valve operability, and the distractions presented to the plant operating personnel. A design modification to the leak detection system trip circuitry and the Duane Arnold Energy Center has proven successful in preventing system isolations caused by the spurious actuations of the thermo-couple monitor. The study suggests that the Office of Inspection and Enforcement consider issuing an information notice which discusses the spurious system isolations caused by the Model 86 thermocouple monitor and describes the design modification implemented at Duane Arnold as a possible corrective action. We have recently been informed that IE is conducting an investigation into spurious system isolations caused by the thermocouple monitor and is considering issuing an information notice on the subject. This engineering evaluation report contains very useful information which would be of assistance in evaluating the need and/or contents of such an information notice.
fi Eric . Leeds, Reactor Systems Engineer Reactor Systems Section 1 Reactor Operations Analysis Branch Office for Analysis and Evaluation of Operational Data
Enclosure:
As Stated Distribution PDR Eleeds WLanning AE0D CF SRubin FHebdon AEOD KBlack CHeltemes 0FC :ROAB :AC:ROAB :DD:AEOD : -
_____:____ ______:_ __ __:. __________: ____.. __ g4]O348860314O NAME :EL .ds:ks :SRubin :FHebdon :
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_____:____________:.___________: ___________: .. _______.... __ y. _______
DATE:03/t//86 :03/l3/86 :03/ /8S : : : :
OFFICIAL RECORD COPY