a
OFFICIAL USE ONLY
From Graph Two take the mid point of intake period (74th
hour) —> 22uc (This is obviously an approximation since
the exact times of intake during the four-day period will
be unknown).
Step 2.
Determine the activity at time of intake.
From equation (2)
epeeter.Tt
SRE o
22
£
5 Ap)
2)1-2 [eyo ?
-
120
~0.27
Ao) = 0.67 ge/br
Since there is assumed a 2200 ml/day intake
0.67 x 24
2200
& 0.0073 pc/ml or gm
II.
Doses to the Thyroid
The following principal assumptions are used in calculation the
doses to the adult thyroid Promintake of activity from fallout material:
a.
The percentages of the isotopes of iodine in mixed fission
products are according to Hunter and Ballau.?
be.
Twenty percent of the ingested yi31 reaches the thyroid.
ce.
The mean energy is 0.22 Mev.
a.
The thyroid weight is 20 grams.
e.
The percentages of shorter-lived isotopes of iodine that
(See V. Discussion below)
reach the thyroid and their doses are according to
reference four.
a
The method of calculation of doses to the thyroid is illustrated by
computing that amount of intake of fission products at the 48th hour
to produce 1.0 rad.
Step 1.
Determine the dose rate on the day of intake of
131
I 3 to produce 1.0 rad to the thyroid.
OFFICIAL USE ONLY
-}.