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36
RADIOLOGICAL CLEANUP OF ENEWETAK ATOLL
OPERATION CROSSROADS: JUNE-JULY 1946
Bikini Atoll was the one chosen as the site of Operation Crossroads,
which wasto be the occasion of the first peacetime detonations of nuclear
weapons.Theclimatic, wind, current, and harbor size requirements could
be met. The selection was influenced by the fact that the population of the
atoll was small and could be relocated easily and that Bikini was close to
Kwajalein and Enewetak Atolls, both of which held military support
facilities. Under the Presidential authority, the Navy also relocated the
people of Enewetak to Meik Island in Kwajalein Atoll while the Bikini tests
were being conducted.°4.55
Three tests were planned for Operation Crossroads, two of which— Able
and Baker—were eventually carried out. The first of these was an aerial
drop, and the second an underwater shot. The bombsweresimilar to those
which had been used against the Japanesecities and which had produced
yields of 13 KT at Hiroshima and 23 KT at Nagasaki.
The yield, stated in KT (thousands of tons), expresses the explosive
equivalent of a weight of TNT. For example, a nuclear bomb havinga yield
of 25 KT would have the same explosive force as a single explosion of
25,000 tons of TNT. A ‘‘nominal”’ yield was one approximately equivalent
to that of the bombs used against the Japanesecities.
Test Able occurred on 30 June 1946. The bomb was dropped from a B-29
aircraft and exploded about 500 feet above the lagoon surface. The bomb
detonated 1,500 feet west of the center target vessel. The vessel did not
sink, but five other vessels were sunk and others were burned or
damaged. The sunken ships were two attack transports, two destroyers,
and a Japaneselight cruiser.°® The yield of the nuclear device of Test Able
was 23 KT.
Test Baker was performed with a nuclear device suspended 90 feet
below a landing ship in the center of another array of ships in the lagoon.
At detonation, a hollow column of water rose to a height of a mile above
the surface of the lagoon. The U.S. battleship ARKANSAS, theaircraft
carrier Saratoga, and the Japanese battleship Nagato were sunk, as well as
other surface vessels and submarines. Some sank immediately and others
took from 7-1/2 hours to 5 days to sink.°’ Test Baker also yielded the
equivalent of 23 KT of TNT.58
Although these tests were successful, Bikini ifself demonstrated a
numberof deficiencies as a test site. One was the lack of land area, which
necessitated the use of surface vessels for planning, administration,
scientific laboratory work, and for life support. A second was the
combinationofisland orientation and wind direction, which prevented the
installation of an adequate airstrip.
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