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Therefore:
(11) (0.05) (0.25) = 0.14 uc, to the bones.
Step 2.
Determine the dose rate to the bones.
With an assumed effective energy of 0.55 Mev (reference 5)
(0.14) (2.2 x 10°) (60 x 2h) (1.6 x 10°)(0.55) » 5.6 x 10%
(100) (7,000)
rads/day
or 0.56 millirads/day
Step 3.
Determine total dose
D total » R
e
where: Raw
initial dose rate
Ae « effective decay constant
D total = 0.56 = 42 miliirads
5.0133
IV.
Methods For Estimating Doses For Prolonged Periods
Of Intake
As suggested above, the thyroid receives greater doses than do the
gastrointestinal tract or bones for periods of intake out to about 20
days after a detonation (except for the first day).
If permissible. in-
takes were based on the thyroid dose only, then Graph Four indicates that
there could be an increasing intake of fission product activity afterabout
the 10th day.
This could be undesirable from the point of view of the
increasing exposures to the gastrointestinal tract and bones, eas well as
leading to possible confusion in interpreting the resultant criteria.
Therefore, Graph Four wes used in constructing the curve for thyroid doses
in Graph Five, except (p) after about the 10th day the intake of fallout
material was held ‘to about 11 microcuries, and (b) the first day's
cf
fissior~ pruduct activity intake was arbitrarily reduced (as shown in
ff
A
a
4
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