ML20081E090

Dow Triga Research Reactor Annual Rept - 1990

ML20081E090
Person / Time
Site:	Dow Chemical Company
Issue date:	06/30/1990
From:	Kocher C DOW CHEMICAL CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
References
NUDOCS 9008060147
Download: ML20081E090 (5)

Text

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MICHIGAN DIYl$10N MIDLAND. MICHIGAN 48667 Director Office of Nuclear Reactor Regulation ATTN Document Control Desk U. S,' Nuclear Regulatory Commission Washington, DC 20555 DOW TRIGA REACTOR FACILITY - DOCKET NO. 50-264 The 1990 annual report for the Dow TRIGA Research Ronctor Facility la attached. ,

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C. W. Kocher Reactor Supervisor 1602 Duilding (517)636-0304 dmp Attachment

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AN OPERATING UNIT OF THE DOW CHEMICAL COMPANY "'" h A' L*

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DOW TRIGA RESEARCH REACTOR ANNUAL REPORT 1994 A. Staff, Licenses, and Training The staff consists of six persons:

C. W. Kocher -Senior Reactor Operator . Reactor Supenisor W. L. Rigot Senior Reactor Operator Assistant Reactor Supervisor T. J. Quinn Senior Reactor Operttar J. J.' Carni Senior Reactor Opera or-M. E. Buchmann-J. D. Romick Buchmann and Romick are trainees and are expected to take the Senior Reactor Operator examinations in' late 1990. Each normally operates the reactor,, under the direction of a licensed Senior Reactor Operator, at least twice each week, performing .

the routine' checkouts and irradiating samples for the analytical program, and each--

takes part in the lecture and examination schedule..

Licenses for the Senior Reactor Operators are current and the earliest renewals will be in 1993.-

The first two-year requalification program was completed in the first quarter of 1990.

Each Senior Reactor Operator took part in the eight quarterly requalification sessions, performed the appropriate operations of the reactor, took part in the annual hypothetical drills, and accumulated the required operating experience. The -

second two-year requalification program started with the second quarter of 1990.

The Reactor Operations Committee now consists of five persons:

J. J. Havel Facility director C. W. Kocher Reactor Supervisor S. W. Maxey: Radiation Safety Officer W. L. Rigot T. D. Lickly Lickly was added to the ROC in June 1990 as a person knowledgeable in the use 'of-radioactive materials and capable of providing a critical evaluation of the operation of the reactor and the associated activities.

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DOW TRIGA RESEARCH REACTOR 7

B ReactorLOperating Experience-

- During the'one yect period starting in May 1989 the reactor was operated for about-seven megawatt hours, mostly at the maximum power level of,95 kilowatts. - Duringi that time there were about 280 operations for the irradiation of samples and about c 260 operations for checkouts and training.

e Ci = Major Changes There were no major changes made to the facility;.the operation of the reactor ut.

power levels above 100 kilowatts to the newly licensed maximum of 300 kilowatts will i

not commence until late 1990 or early 1991.-

There were no new tests or experiments performed which had not been described -

in the Safety Analysis Report. -

D. Unscheduled Shutdowns From May 1989 through the end of April 1990' there were six unintentional-shutdowns.

NUMBER DATE - SCRAM REASON CIRCUIT 1, 5 30-89 rate- operator error - inattention during very

-low power operation at startup 2, 61089 linear operator error - pulled control rod instead of inserting rod when coming to power at

1. kilowatt

3. 11 6-89 rate operator error -lnattention-during _very low power operation at startup

4. 12490 linear ~ noise in the linear channel circuits during -

operation of the control rod drives at very - l

low power .

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5. 13190 linear noise in the linear channel circuits durmg -

L operation of the control rod drives at very low power

6. 1-31-90 linear noise in the linear channel circuits during.

operation of the control rod drives at very low power 2

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DOW TRIGA RESEARCH REACTOR Unintentional shutdowns #1 and #3, involving different operators, occurred during startup when the operators withdrew control rods enough to allow the reactor to come to power at periods close to the set point. This is normal operating procedure and when the power level is greater than about one watt the circuits are stable and no problem occurs. However, at power levels just above source level, where these shutdowns occurred, the random fluctuations at the low count rate of the log channel can sometimes cause the period circuit to trip. The action required to avoid these shutdowns includes the use of restraint in the initial startup from source level.

Unintentional shutdown #2 (same operator as was involved in unintentional shutdown #3) was due purely to lack of attention during establishment of stable operation at a power level of one kilowatt.

Theso unintentional shutdowns were the subjects of reports and critical discussions at the meetings of the Reactor Operations Committee, in the presence of the operators. The topic of operator attention was a part of the requalification sessions, and the reactor supervisor reported and explained these unintentional shutdowns during the semi annual reports to the Radiation Safety Committee.

There have been no unintentional shutdowns due to operator error since late 1989, including the many operations of the reactor by the trainees.

The other unintentional shutdowns, #4 6, were caused by a malfunction of the wiring in the vicinity of the reactor poch the signal from the ccnpensated ion chamber,

( used for the linear channel, was degraded by a poor comact in the coaxial cable.

This cause was identified and repaired within two days of the last occurrence.

A new control console for the reactor has been ordered and is expected to be installed in late 1990; the signal cables will be replaced at that time. No further problem is expected.

E. Major Preventive and Corrective Maintenance On July 301989 one of the reactor control and safety channels failed during an interval between operations of the reactor. This failure was discovered during a scheduled checkout and did not occur during the operation of the reactor. - The affected circuit board was sent to General Atomics for repair; there were no replacement boards. Components on the board were replaced and the system was tested and put back into service. This was not a reportable occurrence.

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On December 20,1989, and again onJanuary 1990, a portion of the circuits of the log channel failed during! operation of the reactor. - These Lwere reportable-occurrences and were duly reported. The cause was identified as poor contacts in=

a switch used to inject calibration signals to test the log channel. -The switch was inspected and tested by the electronics technician and has provided good service since that inspection. The switch is still available from General Atomics and will be ,

replaced if further problems occur.- The installation of the new console in late _1990 will eliminate any further recurrence of this failure.

F. Radioactive Effluents  :

The only radioactive material released to the environment from this facility is argon-41, which is produced from the natural argon dissolved in the water of the pool, subsequently escaping from the pool into the reactor room and from there is emitted from the ventilation system, and from the natural argon present in the air used to transport samples from a laboratory into a terminus in the core of the reactor, The average release after dilution or diffusion is estimated to be less than 25% of-the allowed or recommended concentration.

G. Radiation Exposures Radiation exposures received by facility personnel and visitors are monitored using

- film badges and thermoluminescent detectors. No persons have received exposures approaching 25% of those allowed or recommended in 10CFR20i L

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C. W. Kocher Reactor Supervisor 1 August 1990 4

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