ML20063G729

Dow Triga Research Reactor Annual Rept for 1993

ML20063G729
Person / Time
Site:	Dow Chemical Company
Issue date:	12/31/1993
From:	Kocher C DOW CHEMICAL CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
References
NUDOCS 9402160197
Download: ML20063G729 (4)

Text

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. Dow North America .

... -i ne now cnenecal company-February 7,1994 tedianan n gan .:acu I

P l Director, Office of Nuclear Reactor Regulation Document Control Desk US Nuclear Regulatory Commission Washington DC 20555 - ,

DOW TRIGA RESEARCll REACTOR - DOCKET 50-264 Enclosed is the Annual Report for the Dow TRIGA facility for the year 1993. .

Very truly yours, YfU i

C. W. Kocher, Reactor Supervisor The Dow Chemical Company 1602 Building Midland, MI 48867 Enclosure

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DOW 'IRIGA* RESEARCll REACIDR  :

.. - ANNUAL REPORT- 1993 There were no major changes, maintenance problems, or down time involving the reactor during 1993. Operation of the reactor continues to be plagued with an unacceptably large number of-unintentional shutdowns (SCRAMS), most of which seem to be caused by the control system itself, although there seems to be a year-to-year decrease of these.

There were no US NRC inspections in 1993. The required annual audit was conducted by an outside consultant; recommendations were made and the Reactor Operations Committee has responded to these recommendations. The normal in~ house audits of'_the radiation protection program, safety and housekeeping, and records were also performed and the recommendations acted upon. An audit by the carrier of the nuclear liability insurance was performedi there were no suggestions, open questions, or recommendations.

A. Staff, Licenses, and Training The staff consists of five Senior Reactor Operators, no changes having taken place during 1993:

C. W. Kocher Reactor Supervisor W. L. Rigot Assistant Reactor Supervisor T. J. Quinn Assistant _ Reactor Supervisor M. E. Buchmann J. D. Romick Licenses are current. Rigot and Quinn renewed licenses in 1993, Kocher's license will be up for renewal in 1995, while the Buchmann and Romick licenses will.be up for renewal in 1997. All operators took medical examinations during 1993.

The current two-year requalification program started in the second quarter of 1992 and -

seven sessions have been held. The SROs are current with operating experience and participation in hypothetical emergency drills, Reactor Operation Committee meetings, an annual operating examination, and the annual fuel inventory. Written examinations following each of the seven quarterly training sessions were passed by all operators, with no indication of any deficiencies.

Operation of the reactor is an important part of the training program, since this reactor is operated on an as-needed basis, which results in numerous operations each involving reactivity manipulations, use of the control console, placement and retrieval of samples and handling of radioactive materials. The minimum experience of an operator during 1993 was 29.4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> of actual operating time, involving.180 reactivity manipulations, and the '

maximum experience was 117.1 hours1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> of actual operating time, involving 611 reactivity manipulations. Furthermore, each licensed person performed about 1/5 of-the daily checkout procedures and at least two monthly checkout procedures; one of the monthly .

checkouts (an extensive combination of tasks involving the physical plant, the control system, and operating characteristics) was performed under the direction of another SRO as part of the annual operating examination.

• TRIGA is a registered trademark of General Atomics I

7 February 1993 Page 1 of 3

DOW TRIGA RESEARCH REACTOR

,. ANNUAL REPORT - 1993 R. A. Wolcott has replaced J. J. Havel as chairman of the Reactor Operations Committee:

R. A. Wolcott Facility Director; Chairman C. W. Kocher Reactor Supervisor E. M. Crim Radiation Safety Officer W. L. Rigot Assistant Reactor Supervisor T. D. Lickly Wolcott is the Research Manager in charge of the Dow Michigan Division Inorganic Materials Science and Environmental Analysis group of the Analytical Sciences Laboratory; Kocher and Rigot report administratively to.Wolcott; Crim is the Dow Midland location.

Radiation Safety Officer as well as the TRIGA Radiation Safety Officer and reports, as does -

Lickly, to the Dow North America Health and Environmental Servic'es department.

B. Reactor Operating Experience The reactor was operated for 1.21 Megawatt-days during 1993 for a total of 287 hours0.00332 days <br />0.0797 hours <br />4.74537e-4 weeks <br />1.092035e-4 months <br /> (an average of 14.2% of the available normal working hours) and 1,602 reactivity manipulations, including checkouts and testing as well as the irradiation.of samples.

C. Major Changes During 1993 there were no major changes in the facility and there were no authorizations of new tests or experiments significantly different than those performed previously.

1 D. Unscheduled Shutdowns l There were 47 unscheduled shutdowns (SCRAMS) during 1993, down from 59 during 1992 ..

and 72 during 1991. During the almost ten years following 1-1-81 the yearly average was 6 SCRAMS, with a high of 9 (1983) and a low of 3 (1989), using the control instrumentation installed in 1971 and 1973. After insta!!ation of the new console there were 4 SCRAMS during installation and startup in the last two weeks of December, 1990,72 during 1991,59 1 during 1992, and 47 during 1993. Some of these were celated to hardware problems which have since been fixed, but a large majority seem to be due to two aspects of the control system: computer crashes and noise in the digital smoothing process which produces the period signal.

i About 77% of the SCRAMS were associated with the operation'of the' console: the digital smoothing process (about -34%), computer crashes (about 26%), period SCRAMS at the.

count-rate / Campbell crossover (about 13%), and others (about 4%).

About 15% of the SCRAMS were caused by a malfunctioning board in the control panel; this board was replaced in October 1993 and no further such SCRAMS have occurred.

4 The difference in the total number of SCRAMS between 1992 and 1993 was caused entirely-by the difference in the number of events caused by the digital smoothing process: 29 in-1992 and 16 in 1993. The 1992 experience paralleled the 1991 experience in both number _

(31 in 1991) and in the rate of events.1993 was different but there is no known cause that -

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can be correlated with the SCRAM experience; there were no significant changes made in) +

the software, the hardware, or the operating procedures!

E. Major Preventive and Corrective Maintenance of Safety Significance? g y IC '"

, There have been no maintenance items of safety significance.

l F. Radioactive Effluents 4 U

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The only_ radioactive.materialfnormally released to the environment fromithe facilitytis[ . 1 argon-41, which is produced from actiYation of the natural argon _ dissolved inlthelpool waterW j and subsequently escapes from the pool.into' the reactor room and from there to the outside ,

l of the building,'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. -.

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'During 1993 the reactor room air particulate monitor (sporadically?indichtedlveryjsliflit; i increases of- air-borne radioactivity over'the natural' background:levelsSThese increases - - <

were of the order of the' background leveliand the sum of background plus the' anomalous) '

y radioactivity was' never more than about one-fourth the le. v el requiredito trip the alarm:on: ,

the ~ air particulate monitor.f At times during the year?especially during' the late summer or; d early autumn or during' conditions of thermal inversion, the normal background Fadioactivity M l

level, due to radon daughters, often exceeds the maximum!(background plus: anomalous; .

radioactivity) observed ~ during the 19931 episodes? JAlthough;this effect was closely?

correlated with operation lof the reactor at powerLlevels above?l00 kilowattithereiwere -

many more operations at those power levels throughout that time _'which 'did not: lead to the E anomalous radioactivity, iMonths passed between some episodes! fit was observed that  !

0 the anomalous radioactivity seemed to have a' half-life of about 1.5 minutes; given this,; thel known flow'of air through the particulate monitor, the air flow fro.m the reactor room, and an -

approximate efficienc'y of the G-M detector in the air particula _te monitor it wa's possible'to i. ~q estimate the ,1aximum concentration of radioactive materialsLin- thlairL andithe: total; y '

radioactive material released"during these? episodes? There3was not!enough ;materiali _ ,

deposited _on the filters or in the reactor pool water to allow an_ identification ~ by gamma-ray -

spectroscopy. . If, however, a tentative identification of the radionuclide is made' based on" ' '

the half-life and on the assumption that the nuclide ~is a uranium-235 fission' fragment then" the mleases can be compared with values for_ maximum concentrations listed in '10CFR20.-

Overall the average release after dilution or diffusion is estimhted toYless than 25(ofl '

the allowed or recommende'd maximum concentrationo ,

O. Radiation Exposures 1 l

L Radiation exposures received by facility personnel andLvisitors' are monitored using(filni -

badges and thermoluminesce_nt. detectors. _ -NoL persons have _ receivedlexposures

,- approaching 25% of those allowed or recommended in 10CFR20. '

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C. W. Kocher h) 49N Reactor Supervisor l.

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