Associated with the greater yield of Mike, which was dozens of times
greater than previously experienced, was a corresponding increase in the
fallout radiation.
Contrary to expectations, the winds prevailing at the time
were from the south
or southeast ,> and so most of the radioactive debris fell
on the open seas to the north and northwest.
on the northern islands of the Atoll.
Nevertheless, fallout did occur
Since these islands continued to be
“uninhabited, no harm resulted to humans from this local fallout.
U.S. tests were conducted only at the Nevada Proving Grounds in 1953,
thereupon starting the pattern of tests entirely at the Nevada Proving Crounds
or the Pacific Proving Grounds, each on alternate years.
The next series of
tests in the Pacific was in 1954 under the name Operation Castle.
It involved
a task force, which retained the number Task Force Seven of the 1947 force.
- Five out.of the six tests in this series were at Bikini Atoll, which had
‘not been used for nuclear tests since 1946.
The I5+megaton thermonuclear
tests Bravo in this series was conducted on the surface in Bikini Atoll on 1 March
1954.4.10 The radioactivity of this Bravo event was particularly troublesome by
unexpectedly being carried to the east, rather than to the north as had been foreseen.
Harmful amounts of radioactivity fell out on the inhabitedatells of Rongelar
Ailinginae, and Rongerik and on the Japanese fishing ship Fukuryu Maru.
These
events resultedsharply renewed interest in radiological consequences, with
principal focus on the Bikini series of tests.
The Atomic Bomb Effect Research
Commission. which had been established after the atomic bombing of Japan,
;
became involved.
The Shunkotsu Maru of the Japanese Fisheries Training
'
.
;
Institute cruised the Marshall Island area for sur-ey purposes; this was
followed by a U.S. cruise on the Coast Guard Cutter Roger B. Taney under the name
Operation Troll. .
9.
10.
Nelvin P> Klein. "Fall-Out Gamma Ray Intensity"
Report, UCRI-5125, (1958) °
Reference 1, p 165.
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