ML20081F149
| ML20081F149 | |
| Person / Time | |
|---|---|
| Site: | Dow Chemical Company |
| Issue date: | 12/31/1994 |
| From: | Rigot W DOW CHEMICAL CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9503220011 | |
| Download: ML20081F149 (5) | |
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.k' y., i The Dow Chemical Corns.h 1 March 17,1995 Meand, Mchigan 48ce7 A
Director, Office of Nuclear Reactor Regulation '
Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555 To Whom This May Concern, Please find enclosed the Annual Report for the Dow TRIGA facility for the year 1994.
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Ward L. Rigot 9 hm Reactor Supervisor 1602 Building ,
Enclosure i
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DOW TRIGA* RESEARCH REACTOR ANNUAL REPORT - 1994 There were no major changes, maintenance problems, or down time involving the reactor during 1994. Operation of the reactor continues to be plagued with an unacceptably large number of 1 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 1994. The required annual audit was conducted by an l
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 record.s were also performed and the recommendations acted upon.
A. Staff, Licenses, and Training The staff consists of four Senior Reactor Operators, C. W. Kocher, former Reactor Supervisor retired from The Dow Chemical Company in 1994 and no longer serves as a staff member. W. L. Rigot has assumed his duties as Reactor Supervisor and J. D. Romick has been appointed Assistant Reactor Supervisor.
W. L. Rigot Reactor Supervisor T. J. Quinn Assistant Reactor Supervisor J. D. Romick Assistant Reactor Supervisor M. E. Buchmann Licenses are current. Rigot and Quinn licenses will be up for iemwal in 1999, while the Buchmann and Romick licenses will be up for renewal in 1997. All aperators took medical examinations during 1993.
The current two-year requalification program started in the second quarter 1992 and has been completed; all operators have sucessfully completed the compiahensive examination which was given at the end of the eighth quarterly requalification s:ssion. The,new two- '
year requalification program has started with three quarterly sessions held during 1994; all operators have participated and successfully completed the regirements for these sessions.
The SROs are current with operating experience and participcion in hypothetical emergency drills, Reactor Operation Committee meetings, an annual operating examination, and the annual fuel inventory.
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 1994 was 25.7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> of actual operating time, involving 183 reactivity manipulations, and the maximum experience was 168.1 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 840 reactivity manipulations. Furthermore, each licensed person performed about 1/4 of the daily j 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.
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- TRIGA is a registered trademark of General Atomics 9 March 1995- Page 1 of 4 f
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W' DOW TRIGA RESEARCH REACI'OR ;
l ANNUAL REPORT- 1994 l S. B. Butts has replaced R. A. Wolcott as Facility Director and sits as chairpersonor the i Reactor Operations Committee, R. M. A. Hahne has replaced E. M. Crim as the Radiation l Safety Officer and T. J. Quinn has replaced C. W. Kocher as a member of the committee, i Facility Director; Chairman j S. B. Butts W. L'. Rigot Reactor Supervisor :
Radiation Safety Officer l R. M. A. Hahne T. J. Quinn Assistant Reactor Supervisor
,; T. D. Lickly.
. S. B. Butts is the Research Manager in charge of the Dow Michigan Division Inorganic, .
Environmental and Thermal Analysis group of the Analytical Sciences Laboratory; Rigot !
and Quinn report administratively to Butts; Hahne is the Dow Midland location Radiation J Safety Officer as well as the TRIGA Radiation Safety Officer and reports, as does Lickly, to ,
the Dow North America Health and Environmental Services department. l 1
B. Reactor Operating Experience 1
The reactor was operated for 1.27 Megawatt-days during 1994 for a total of 301 hours0.00348 days <br />0.0836 hours <br />4.976852e-4 weeks <br />1.145305e-4 months <br /> (an average of 15.1% of the available normal working hours) and 1,592 reactivity manipulations, including checkouts and testing as well as the irradiation of samples.
C. Major Changes ,
During 1994 there were no major changes in the facility and there were no authorizations of new tests or experiments significantly different than those performed previously.
D. Unscheduled Shutdowns There were 42 unscheduled shutdowns (SCRAMS) during 1994, down from 47 during 1993, 59 during 1992 and 72 during 1991. During the almost ten years following 1-1-8f 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 installation of the new console there.
were 4 SCRAMS during installation and startup in the last two weeks of December,1990, 72 during 1991,59 during 1992,47 during 1993 and 42 during 1994. Some of these were related 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. ,
About 83% of the SCRAMS were associated with the operation of the console: the digital smoothing process (about 45 %), computer crashes (about 21%), period SCRAMS at the count-rate / Campbell crossover (about 5%), and others (about 7%).
The difference in the total number of SCRAMS between 1993 and 1994 can be attributed to a better understanding by the operators of the algorithm used for generating the digital input to the safety channel and a-better overall understanding of the operation of the console.
9 March 1995. Page 2 of 4
DOW TRIGA RESEARCH REACTOR
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ANNUAL REPORT - 1994 E. Major Preventive and Corrective Maintenance of Safety Significance There have been no maintenance items of safety significance.
F. Radioactive Effluents The only radioactive material normally released to the environment from the facility is argon-41, which is produced from activation of the natural argon dissolved in the pool water and subsequently escapes from the pool into the reactor room and from there to the outside of the building, and from the natural argon present in the air used to transport samples from a laboratory into a terminus in the com of the reactor.
During 1993 the reactor room air particulate monitor sporadically indicated very slight increases of air-borne radioactivity over the natural background levels. These increases were of the order of the background level and the sum of background plus the anomalous radioactivity was never more than about one-fourth the level required to trip the alarm on the air particulate monitor. At times during the year, especially during the late summer or early autumn or during conditions of thermal inversion, the normal background radioactivity level, due to radon daughters, often exceeds the maximum (background plus anomalous radioactivity) observed during the 1993 episodes. Although this effect was closely correlated with operation of the reactor at power levels above 100 kilowatts there were many more operations at those power levels throughout that time which did not lead to the anomalous radioactivity. Months passed between some episodes. It was observed that the anomalous radioactivity seemed to have a half-life o'f about 15 minutes; given this, the known flow of air through the particulate monitor, the air flow from the reactor room, and an approximate efficiency of the G-M detector in the air particulate monitor it was possible to estimate the maximum concentration of radioactive materials in the air and the total radioactive material released during these episodes. There was not enough material 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 fraj; ment th'en the releases can be compared with values for maximum concentrations listed in 10CFR20.
Overall the average release after dilution or diffusion is estimated to be less than 25% of the allowed or recommended maximum concentration.
There was one three day period when the continuous air monitored was measuring significantly higher than normal levels of radioactivity. The highest was on a monday morning when the recorded level was ~900 cpm; the normal background is ~100-200 cpm.
The filter was removed from the holder and the isotopes identified as radon daughters from naturally occurring radioactive material 238U and 232Th. No other radioisotopes were identified. We feel that the increased background was due to a weather inversion, coupled with a slight southerly wind. We beleive that the radon source is from the gas-fired electrical generating facility located just south of the Dow manufacturing division.
9 March 1995- Page 3 of 4
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DOW TRIGA RESEARCII REACTOR ANNUAL REPORT- 1994 G. adiation 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 10CFR20.
W. L. Rigot Reactor Supervisor 2 February 1994 l
9 March 1995. Page 4 of 4 I