ACE? 4
OFTIStAL USE ONLY
UCRL-12378
ESTIMATE OF RADIATION DOSE TO THYROIDS OF THE RONGELAP
Ralph A. James
UNIVERSITY OF CALIFORNIA
Lawrence Radiation Laboratory
Lawrence Radiation Laboratory, University of California
Livermore, California
ar rary
CHILDREN FOLLOWING THE BRAVO EVENT
Livermore, California
Contract No. W-7405-eng-48
December 16,
1964
ABSTRACT
An estimate is made of the radiation dose to the ithyrcids of Rongelap
children following the Bravo event of March 1, 1954. The available expertmental data are used to estimate the dose under two alternate assumptions of
ESTIMATE OF RADIATION DOSE TO THYROIDS OF THE RONGELAP
CHILDREN FOLLOWING THE BRAVO EVENT
~
Ralph A. James
mode of intake:
(a) all of the intake was by inhalation, and (b) all of the
intake was by oral ingestion.
GENERAL INFORMATION
December 16, 1964
s-
It is concluded that the most probable dose to
the thyreid of a 3- to 4-year-old girl is in the range 700 to 1400 rad,
The cloud arrival time ia given! as H+4to6 hours.
The duration of
the cloud passage is less well known, but probably lies in the range of 8 to
16 hours.
In all calculations we will assumethat cloud passage was in the
interval H + 6 to H + 18.
ns.
The residents of Rongelap were evacuated at H +51 hours.
Reliable
\ Ouax
t ydou
dose-rate measurements were not obtained at that time, but the gamma dose
rate 3 feet above the ground was measured as 375 mR/hour 7 days after the
detonation.
3.8 R/hour.
Assuming i? decay, the H + 24 hour dose rate was then about
.
:
-
The sources of exposure to the thyroid which must be considered are:
{1} Whole-body gamma dose,
(2) Internal deposition of iodine isotopes,
{
Whole-Body Gamma Dose
.
cloud but only from fallout.
Sask}
OFFICIAL USE ONLY
See PS sagt UES
In particular, it appears that this estimate does not include the dose from the
ertiaea
The whole-body dose was eatimated! to be 175-R. The exact method of
making this estimate is not given, #0 an independent entimate isitade below.