ML19305C363
| ML19305C363 | |
| Person / Time | |
|---|---|
| Site: | University of Michigan |
| Issue date: | 03/13/1980 |
| From: | Kerr W MICHIGAN, UNIV. OF, ANN ARBOR, MI |
| To: | |
| References | |
| NUDOCS 8003260614 | |
| Download: ML19305C363 (2) | |
Text
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THE UNIVERSITY OF MICHIGAN PHOENIX MEMORIAL LABORATORY l
l FORD NUCLEAR REACTOR ANN ARBOR, MICHIGAN 48105 j
Reportable Occurrence No. 9 March 13, 1980 U.
S.
Nuclear Regulatory Commission Region III Attention:
Mr. James G.
Keppler 799 Roosevelt Road Glen Ellyn, Illinois 60137 Gentlemen:
The purpose of this letter is to provide a written report of the reportable occurrence at the Ford Nuclear Reactor (FNR) on March 3,
1980.
At 0908 on Monday, March 3,
1980, approximately 45 mci of Br-82 35 hours4.050926e-4 days <br />0.00972 hours <br />5.787037e-5 weeks <br />1.33175e-5 months <br />) was inadvertently released through Stack No. 2 (Tl/2
=
during a routine hot cave preparation of a bromine-motor oil sample.
At approximately 0919, the Stack Mobile Air Particulate Monitor (MAP) reached a maximum reading of 35,000 cpm (alarm point setting
=
10,000 cpm) and the Stack #2 Gaseous Activity Detector (GAD) indicated a slight increase from 40 cpm to 150 cpm (alarm point setting
=
650 cpm).
The reactor was shut down at the time of the release.
Br-82 was identified as the isotope causing the Stack MAP alarm after a strip of filter tape which had passed in fron: of the MAP detector was removed, sealed in a plastic bag, and analyzed on the GELI detector.
Approximately, 0.5 Ci of Br-82 were discovered on the filter tape.
The Stack #2 charcoal filter (and its pre-filter) and isokinetic filter were removed, sealad individually in plastic bags and analyzed quantitatively on the GELI detector.
All filters which were removed were immediately replaced with new filters.
The total sample collection time between 0908 and 1335 was 267 minutes.
The total sample volume was approximately 9.91E6cc and the total effluent volume out Stack #2 was approximately 8.62E10cc.
The GELI detector analysis indicated that approximately 4.75 pCi of Br-82 (corrected to T=0, assuming some decay) was impregnated in the 0
h04R 1 71880 8 0032 606A4
e charcoal. filter cartridge, 0.026 uCi on the charcoal filter cartridge pre-filter, and approximately 0.0023 pCi on the Stack #2 isokinetic filter.
The calculated Br-82 release was based upon the activity measured in the charcoal filter martridge.
The approximate collection ef-ficiency of the charcoal filter cartridge is 90%.
Past experience has shown that the membrane isokinetic and pre-filter collection efficiency for gaseous halogens (bromine and iodine) is approximately 10%.
For the 267 minute stack e f fluent sample collection period, the average Br-82 concentration was approximately 5.23E-7 uCi/cc.
Most of the bromine was released within the.267 minute time span because the Stack MAP and GAD monitors indicated near-background levels after that time.
Further readings on the monitors which were slightly above background levels can be attributable to the bromine plating-out on surfaces of the G-M tubes.
Therefore, calculations indicate that approximately 45.08 mci of Br-82 were released through Stack 42.
The average concentration of the total release over a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period is approximately 9.69E-8 uCi/cc.
Applying the allowed dilution factor of 400, calculations indicate that the concentration over a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period was 2.42E-10 uCi/cc (10 CFR 20.601; Table II, Column #1); therefore, the total estimated; bromine release was approximately 0.61% MPC.
The bromine release occurred in the preparation procedure.
The radio-active bromine encased in quartz is frozen in liquid nitrogen.
The quartz is broken and the frozen bromine is dropped into a solution of 1-octadecene carbontetrachloride.
The bromine chemically binds to the octadecene thus eliminating the possibility of free gaseous release.
Before the bromine had dissolved and reached chemical equilibrium with the solution, the operator bumped the solution beaker and spilled the small amount which was released as free bromine.
In order to decrease the likelihood of a recurrence the steps in the procedure are being clarified so that the operator is instructed to make immediate use of a protective solution.
Sincerely,
%D William Kerr, Director l
Michigan Memorial-Phoenix Project I
WK/z l
xc:
R.
Burn J.
Jones M.
Driscoll i
3 L