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UCRL- 12273
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OFFICIAL USE ONLY
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December 16, 1964
Ralph A. James
ESTIMATE OF RADIATION DOSE TO THYROIDS OF THE RONGELAP
CHILDREN FOLLOWING THE BRAVO EVENT
Contract No. W-7405-eng-48
Livermore, California
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UNIVERSITY OF CALIFORNIA
Lawrence Radiation Laboratory
OFFS!AL USE ONLY
ee NR.
410817
An estimate is made of the radiation dose to the thyrolds of Rongelap
ABSTRACT
December 16, 1964
Lawrence Radiation Laboratory, University of California
Livermore, California
Ralph A. James
ESTIMATE OF RADIATION DOSE TO THYROIDS OF THE RONGELAP
CHILDREN FOLLOWING THE BRAVO EVENT
cn as ees
Reliable
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The whole-body dose was estimated! to be 175-R. The exact method of
making this estimate ig not given, so an independent eatimate iarhade below.
In particular, it appears that this estimate does not include the dose from the
cloud but only from fallout.
Whole-Body Gamma Dose
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(2) Internal deposition of iodine isotopes.
(1) Whole-body gamma dose.
The sources of exposure to the thyroid which must be considered are:
detonation. Assuming t''*? decay, the H + 24 hour dose rate was then about
3.8 R/hour.
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rate 3 feet above the ground was measured as 375 mR/hour 7 days after the
dose-rate measurements were not obtained at that time, but the gamma dose
The residents of Rongelap were evacuated at H +51 hours.
The cloud arrival time is given! as H +4to6 hours. The duration of
the cloud pasgage is less well known, but probably lies in the range of 8 to
16 hours. In all calculations we will assume that cloud passage was in the
interval H + 6 to H + 18.
GENERAL INFORMATION
the thyroid of a 3- to 4-year-old girl ia in the range 700 to 1400 rad.
mental data are used to estimate the dose under two alternate assumptiona of
mode of intake: (a) all of the intake was by inhalation, and (b) all of the
intake was by oral ingestion. It ia concluded that the most probable dose to
children following the Bravo event of March 1, 1954. The available experi-
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