whore P is the fraction ef the fission produste actually deposited,
is the energy of the explosion in kilotons, and m square miles is the
area over which the products are spread.
, “Gust what the true wilue af P will be is to some extent a
matter of speculation, However, the writer believes with som
eonfidense that P will met exceed 0.001, ‘this value is about one-.
different |
tenth that fount at Trinity. Having regard to the very
heights ef burat (600 fest or more as against 100 fect) the value 0,001
is considered a very safe maxim value to assume, Tae
“Mperbow) = 5
~
where fT is in hours.
factor 10,
'
this formila may well overestimate 3 by &
Clearly, if the products remained fixed on the mirface, it
would not be safe to venture into the central area eve for a few
mimstes until tw or three days after the explosion have passed,
There are, however, at least tw further factors that will
considerably reduce the radiation hazards, The first is the turbulent
diffusion ef the fission praixsts dom into the water, where their
effect is much reduced, or even completely removed. The second is
the carrying away of the products by the tide. The second factor is not
altogether material, because the radiation hazard will still remin
in the water, although its center will have moved,
'
‘For simplicity, eonsider enly diffusion dowmvwards from the
surface.
wilh be
The density’of radioactive products at depth Y at time T
nr) (4p any oT/aer
where R(T) is the radiation density at the surface assuming the
products have not moved, and K is the eddy soefficient of diffusion,
Let Xd be the mean free path of the -radiation in wter
(actually 1 is about 90 en), Then the radiation density above the
, Surtane af the miter ds
gemexamyt (“eh ett a
Bvaluating this expression, we get
(ae
eet ++ (GE)
RCT
whe
' ™
, COPIED/DOE §
LANL RGaft
re A (x) ae
Ye
Xe
»
/> ox
kA
and ds the probability integral.
,