ML20203N902
| ML20203N902 | |
| Person / Time | |
|---|---|
| Site: | Breazeale Nuclear Reactor |
| Issue date: | 04/28/1986 |
| From: | Hosler C PENNSYLVANIA STATE UNIV., UNIVERSITY PARK, PA |
| To: | NRC OFFICE OF ADMINISTRATION (ADM), Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8605060196 | |
| Download: ML20203N902 (2) | |
Text
O THE PEN NSY LVA NI A STATE UNIVERSITY VICE PRISIDENT FOR RESEARCH AND DEAN OF Tile GRADUATE SCIIOOL 114 Kl.RN GRADUATE BUILDING UNIVERSITY PARK, PA lhM2 C. L. Ilosler Teicihe:
Vece Preudent aiki Dean 814 865-2$16 814-865-6331 April 28,1986 Director Dffice of Nuclear Reactor Regulations Office of Nuclear Regulatory Ccnmission Washington, D.C. 20555 ATTN: Document Centrol Desk Dear Sir er Madame On Friday, April 18, 1986 at approximately 4:00 p.m., an experiment was being perf ormed to check the operation of a new instrumented f uel element with one thermocouple connected to either a recorder or a new temperature controller device. The temperature controller also initiates the temperature scram. The temperature measurements made during this experiment required interchanging thermocouples with the various temperature readout instruments af ter each measurement. The first set of measurements was perfcrmed at steady state power. The remaining set of measurements was performed by pulsing the TRIGA ccre with three separate $2.5 pulses. All instruments performed normally for the first pulse after which the connections were transferred.
During the last two pulses, the console temperature readout connected to the temperature scram gave readings that were icw by approximately 60* C. Further examination of these readings showed that one leg of the T.C. was shorted in the connector. Thus, during the last two pulses, the temperature scram system could not have perfcrmed its intended safety function. The NRC Region I Office was notified of this by telephone and telex on Monday, April 21, 1986.
The Technical Specifications require that the temperature scram be operable during both steady state and pulse operations. H owe ver , it should be mentioned that the temperatare scram does not have a safety function during the pulse. This is because the pulse time is short compared to the time response of the T.C.
This problem occurred because the standard operating procedure, SOP-2, was not followed. This procedure requires an electrical checkout of the temperature scram prior to reactor operation when the thermocouple connections are changed. The temperature scram system is new; therefore, all operators have been rcminded of this procedure requirement to prevent recurrence of this 9605060196 860428 PDR ADOCK 05000005 I
3 g PDR t 0 AN I: QUAL. OPPOR IUNITY UNIVI RSITY k
evSi:t . Emphasis will be placed on this procedure compliance during the annual requalification review of PSBR procedures. In addition, the mechanical integrity of the thermocouple connections has been improved so that a short of
'this type is not likely to occur again.
.)
Sincerely,
$~
Charles L. Hosler, Jr.
Vice 'esident for Research and Dean of the Graduate School CLH/skr cc: Thomas C. Elsasser, Region I j'g&L h /L clMU MARY A. ! "T::AM:R, Nctory PubMe Univer.ity Pcrk, Centre Co., Pa.
My Com:tdssion Dpires May 8,1989
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