DNA 1240H-2
Certain analyses indicate that the transit dose should be about 10-30
percent of the deposit dose during the period of deposition, the percentage increasing with increasing distance from surface zero,"
An idealized theoretical model for predicting peak dose rates and
doses for underwater bursts its presented in Chapter 7 of Ref&rence 47,
whereas & more generolized model for calculating such histories is
given in Reference 48.
The model of Ref. 47 is briefly described,
followed by a summary of the model presented in Reference 48.
THE MODEL OF REFERENCE 47
In this model, let
t; = time in hours of initial arrival of activity (leading
edge of base surge)
t, = time in hours of final arrival (trailing edge )
dose rate corrected for decay to reference time of 1 hr
™
"
= dose rate from airborne activity at any time t
after buret
= at28, assumed radioactive decay
&
¢
d
«= O for t & t; and for t>tr
dy = do (R,@) for ty t Cty, where R and © are polar
coordinates of the point with reference to surface zero.
In Ref. 47, for the specific shots under discussion, estimates of dp,
ty and ty are plotted as functions of distance R.
transit dose, D, may be expressed by
te
Then the total
tr
ol
1
1
and evaluated by
pe}
0.2
ty
2. ” lt
{ft os
(17-2)
For convenience in calculating, the quantity in brackets is also
plotted in Ref. 47.
In this simple model, d, may be thought of as resulting from an
average amount of active material distributed through that portion of
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