Gong
9 to 94 hour flight plan which included surveys over the atoll as well
as flights out to the end of the isodose plot (150 to 300 miles),
Samples
of contaminated water were obtained from Project 2,62 to measure the decay
time of the radioactivity in order to extrapolate the measurements back
to the fallout time,
One aircraft was to be flown over the Bikini Atoll area, and the
downwind contaminated area delineated,
The survey was scheduled for
(Tewa) minus 2,
RESULTS
The preshot survey found downwind contamination, as expected, with
a peak intensity around 0,4 mrfhr,
See attached Fig. 2.64-1,
The D-day survey was started late on D-day to avoid contamination
of the aircraft,
The lower outside boundary was carefully delineated,
See Fig. 2.64~2 attached,
On D +1 and D + 2, two aircraft were used to survey the contaminated
area,
This enclosed approximately 36,000 square miles,
On D + 3 and D + 4, one aircraft was used to follow the contaminated
area in the vicinity of the hot line,
imately 2500 squsre miles,
This enclosed an area of approx-
See Fig, 2,64-3 attached,
In surmary, the aerial survey flights delineated the background
contamination prior to the shot, surveyed the total contaminated area
on D + 1 and D + 2, and delineated the hot area not only on D + 1 and
D+ 2 but followed this area on D + 3 and D+ 4,
The prelirinary results
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show that this area remained relatively stable throughout this time interval,
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