Intensity levels below are estimated using a ship contamination model that is
dependent on radiological decay rates and the rapidity with which hulls accumulate
contamination. The decay rate of t7!-3 that was used for Operation CROSSROADS is
applied in this report, but an estimated uncertainty in the exponent of +0.2 is also
considered. This variation is of the magnitude that thermonuclear devices can exhibit
within days after detonation.
By influencing the parameter S described in Section 2,
the steeper decay rate (t7 1-5) results in larger contamination doses for all ships. In all
cases, the variation in dose with decay rate is within a factor of two.
Also as
determined for Operation CROSSROADS, saturation of ship hulls occurred within the
order of one day. Estimated limits for the time to saturation are 0.5 and 2 days. For
all ships, these saturation times influence the contamination dose by less than a factor
of 1.5. The combined uncertainty from decay rate and saturation time, approximated
as a normal distribution, is shown for each ship below at the estimated 90-percent
level,
Ship
Ship Contamination Dose
APACHE
0.43 + .17 rem
BAIROKO
BELLE GROVE
CURTISS
EPPERSON
ESTES
AINSWORTH
GYPSY
0.20 + .09
0.24 + .12
0.17 +.10
0.12 + .06
0.16 + .07
0.27 + .13
0.31 + .12
" LST-551
LST~762
LST-825
LST-975
NICHOLAS
PHILIP
RENSHAW
:
0.21 + .08
0.16 + .07
Fe
--0.19 + .10
0.63 + .4
0.44 + 3
SIOUX
0.64 * °
155