ML20210L466
| ML20210L466 | |
| Person / Time | |
|---|---|
| Issue date: | 03/14/1986 |
| From: | Hebdon F NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| To: | Vollmer R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| Shared Package | |
| ML20210L468 | List: |
| References | |
| NUDOCS 8604290345 | |
| Download: ML20210L466 (1) | |
Text
r FPR MAR 141986 MEMORANDUM FOR: Richard H. Vollmer, Deputy Director Office of Inspection and Enforcement FROM: Frederick J. Hebdon, Deputy Director Office for Analysis and Evaluation of Operational Data
SUBJECT:
SPURIOUS SYSTEM ISOLATIONS CAUSED BY THE PANALARM MODEL 86 THERM 0 COUPLE MONITOR Enclosed is an AE0D engineering evaluation report concerning system isolations commonly caused by spurious trips of the Panalarm Model 86 thennoccuple monitor.
The study found that elevated sensitivity of the thermocouple monitor makes the instrument highly susceptible to spurious trips caused by momentary electrical disturbances. 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 at the Duane Arnold Energy Center appears to have proven successful in preventing spurious system isolations caused by the thermocouple ,
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.
Recently, we have become aware that IE has also initiated a limited investi-gation into spurious isolations caused by the Model 86 thermocouple monitor ,
and is considering issuing an information notice on this subject. We believe -
that the enclosed engineering evaluation report contains information which would be of significant assistance in developing the information notice. We ,
would suggest, therefore, that IE go foward with its plans for an information notice and use the information contained in the engineering evaluation for its development.
If you or your staff have any questions concerning the enclosed engineering evaluation report, please contact Eric Leeds of my staff on extension 24445.
/d/
Frederick J. Hebdon, Deputy Director Office for Analysis and Evaluation of Operational Data
Enclosure:
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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 commonly 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.
S er d Eric . Leeds, Reactor Systems Engineer Reactor Systems Section 1 Reactor Operations Analysis Branch Office for Analysis and Evaluation of Operational Data
Enclosure:
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0FFICIAL RECORD COPY
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