1952 to generate the very powerful detonation of the MIKE device in Operation
IVY, but MIKE was not a deliverable nuclear weapon.

In BRAVO, the first

CASTLE test, a device more powerful than MIKE was exploded that, although not
a weapon, was capable of delivery by an aircraft (13: 26).
CASTLE also was the first Pacific series in which the Lawrence Livermore
National Laboratory (LLNL) provided a nuclear device for testing, detonated as
Shot KOON.

All previous nuclear test devices had been designed at the Los

Alamos National Laboratory (13: 26).
4.10.2

CASTLE Test Operations.

Numerous technical experiments were carried out in conjunction with each
of the six detonations.

These experiments measured the yield and efficiency

of the devices and attempted to gauge the military effects of the explosions.
The approximately 12,700 DOD participants in this series had duty stations at
the AEC design laboratories or were members of units performing separate
experiments or various support roles.

Almost all of the Navy support person-

nel were at Bikini, where Navy ships provided living quarters for participants
who were evacuated from the islands for the first test and then could not
return to live there because of the potential radiation exposure (13: 2).
4.10.3

Dose Summary for Operation CASTLE.

Among the CASTLE detonations, only BRAVO produced significant, unexpected
personnel radiation exposures.

This first shot of the series, which signif-

icantly exceeded its expected yield, released large quantities of radioactive
materials into the atmosphere.

These materials were caught up in winds that

spread the particles over a much larger area than had been anticipated.

This

resulted in contamination and exposure of Marshall Island residents, Japanese
fishermen, and U.S. personnel on distant atolls or aboard various vessels.

Acute radiation effects were observed among some of these people (13: 3).
Some DOD personnel exceeded the maximum permissible limit of 3.9 rem of
gamma radiation within any 13-week period of the operation.

BRAVO fallout on

some Navy ships resulted in personnel who had doses approaching or exceeding
this limit.

To allow for completion of the CASTLE tests, it became necessary

to issue a number of waiver authorizations permitting doses of as much as

105

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