CHAPTER 17
The final report, "Mechanism and Extent of the Early Dispersion of
Radioactive Products in the Water,"® which was not issued until March
1962, states that it "ie the result of painstaking analysis of measuremente obtained,” but "for a mumber of reasons the measurements left
something to be desired." According to this analysis, 32% of the total
activity in the water was found in the thermocline (at 110 meters) and
above, and 68% at depths of 200 to 300 meters.
The deep activity was
found to be complexly distributed in laminae that moved more or less
independently of the surface and other waters. It was concluded that
the mechanism that gave rise to this distribution was an emergence of a
deep colum of water at early times following the detonation and a subsequent mixing of these deeper waters with the surface layers and their
sinking to an intermediate depth as a result of instability.
It is
postulated that the emergence of the colum gave rise to a mass of water
moving from east to west on the surface, perhaps due to the earth's
rotation.
Values given in Ref. 8 of early-time maximum radioactivity at the
water surface, as determined by survey aircraft, are higher by factors
of 3 to 7 than those given in Ref. 31.
According to Ref. &, the 27
min, 33 min, and 130 min maximm surface dose rates over the radioactive
c™
pool of 550 r/hr, 230 r/hr, and & r/hr, respectively, were derived by
arbitrarily doubling aircraft results thet had been corrected to 3 ft
above water. This doubling was done to roughly reduce these measure-
ments to in-situ measurements made by the probe.
The area of surface
activity at H + 30 min is tabulated as 5.5 sq. mi.
According to Ref.
31, the earliest aerial survey at H + 19 min established that the
principal contaminated zone of water was about 2.5 miles in diameter,
with an area of about 5.3 square miles, and at that time dose rates
varied between 32 and 70 r/hr at 3 ft above the water.
Several sets of
radiac data-telemetering transmitters were dropped into the water by
eircraft at various times from H + 2 min to D +1 day.
It was planned
for these instruments to measure the dose rates in about the top 6
inches of water and transmit the information to the primary radar room
aboard the CVL-49.
Of the original 5 sets dropped, telemetering pulses
were received from only four. Of these, two units were of too high a
range to produce data, and one unit transmitted intermittently. One
unit produced consistent and apparently reliable data (although no range
and bearing information was obtainable) that compared satisfactorily
with information obtained from another unit dropped at D+ 5.3 hrs.
Available telemetered data indicate that dose rates in the top few inches
of water somewhere in the area of the original circular upwelling were
about 40 r/hr at about 1 hr after burst, and decreased to about 1.5 r/hr
at 6.67 hr (400 min).
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