Therefore the interior intensity at any time t after the detonation is given by:
I(t) = Fosr i? E - exp} ao D,, (t) | :
(7)
Since detailed radiological data for the waters of Bikini Lagoon are not available
for Operation CASTLE, several assumptions are made in order to apply the CROSSROADS ship contamination mode! to the ships at CASTLE. It is documented that the
anchorage areas in the lagoon became contaminated to varying degrees following Shots
BRAVO, UNION and YANKEE. The assumption is made that ships entering the lagoon
after each of these shots would reach the saturation level of contamination if they
remained in the lagoon.
The rate and level at which hulls become saturated is
dependent on the intensity of the water surrounding the ship.
was found
that
ships
remaining
saturation within one or two days.
in
radioactive
lagoon
At CROSSROADS, it
water generally
reached
Based on these observations, this analysis assumes
that the ships’ hulls approached saturation linearly over a one-day period, i.e., any ship
remaining in the lagoon for 24 hours becarne saturated. This assumption allows (high-
sided) exposure estimates to be calculated without detailed knowledge of the water
environment, leading to:
I(t) = Fst
-1.3
.
(8)
It is further assumed that, upon departing the contaminated lagoon water, hull
and piping intensities were reduced by one-half, and that subsequent decay while out
1.3
decay rate.
of the lagoon followed the t°~
With these assumptions, the model developed for CROSSROADS ships is used to
estimate the personnel exposure at Operation CASTLE due to contaminated lagoon
water. Values of S and F(from Reference 6) for pertinent ship types are given below.
Ship Type
CVE
TAP, LSD, AV
AGC
LST
ATF, ARSD
DDE
5 (mR-day 2*4)
1570
1570
1570
1570
1570
1800
F.
0.10
0.15
0.29
0.33
0.39
0.39
30
FS
160
240
310
520
610
700