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RESULTS
Approximately 90% of all project instrumentation functioned properly,
and no significant demage to any station other than the one located on Namu
Island was reported.
Even in this case the protective cone remained upright
even though crushed and a useful semple was collected.
All island, barge
and raft stations received fallout, as well as about half of the skiff
stations; and activity levels were in general high, the highest being
observed on Aomoen and Namu Islands, the YFNB-29, raft #3 and the skiffs in
the northwest quadrant.
Surface readings of samples collected on island,
reft and barge stetions everaged 2.0 r/hr et 1200 on D+l with some as high as 5.0
r/hr at 0900 on D+2,.
The time of arrivel of fallout was sbout 7 minutes at the
YFNB-29 and 37 minutes at the YFNB~13,
All project ships received significant fallout, the approximate time of
arrival being H+2 hours for the YAG-39, H+4.5 hours for the YAG-4O and H+7.2
hours for the LST-611.
The highest activity level measured was approximately
41,0 r/hr at Ht+5.2 on the deck of the YAG-39, while the maximum deck intensity
observed on the YAG-40 was about 7.0 r/hr at H+6.9 hours.
Extrapolated to a
deck condition without washdown the maximum intensity level observed on the
LST-611 wes approximately 1.0 rfnr.
Activity measurements, decay and gamma
spectra measurements, and physical observations of fallout material were
performed at eerly times in the shielded laboratory aboard the YAG-4O.
great majority of thesfithta are being reduced at the present time.
The
It is
evident, however, thethife active fallout particles were very similer to those
ae
observed following na shot of Operation Castle.
These were of three
general types: (1) unchenged coral particles, (2) particles with CaO or Ca(OH)5
interiors and a thin Cal03 exterior shell, end (3) branch clusters, resembling
agelomerated snowflakes.
Early examinetion of a limited number of particles
e
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SPIED,
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