CHAPTER 1
INTRODUCTIONS
Radiation-fields produced by fallout from ea nuclear detonation
oreate debilitating effects far beyond the range of its blast damage.
Information on transport and distribution of fallout and knowledge of
its physical, chemical, and radiochemical properties are prerequisite
to development of countermeasures against its radiation fields. At
Operation CASTLE the transport and distribution of fallout was prineipally the concern of Projects 2.5a and 6.43 Project 2.56 stuiled the
fallout on islands near the shot point; investigation of fallout prop-
erties was the concern of Projects 2.6a and 2.6b.
lel
OBJECTIVES AND BACKGROUND
The purpose of Project 2.6 was to investigate the chemical,
physical, and radiochemical properties of the fallout fors
a. Deducing the mechanism whereby conteminant is formed,
be Assessing radiological situationa,
c. Specifying realistic simulents of radiological contaminants
for use in contamination and decontamination tests.
d. Interpreting the data obtained in proof testing atomic
warfare countermeasures for ships,
1.1.1
Mechaniem
of Contamination
The contamination formed from surface or sub-surface detonation
of a nuclear weapon has important
TAtaryoppeeanences »
at Operations CROSSROADS,5/JANGLE,*+//and
It was found
IVY¥+</that high levels of
surface contamination were produced as a result df surface or sub-surface
detonations. Eech of these operations represented a unique condition
of detonation, but provided insufficient data to establish bases for
predicting radiological effects for a wide range of probable conditions
of detonation, An unméerstanding of the mechanism whereby contamination
is produced is necessary in saking such predictions. Data obtained in
CASTLE are applicable in answering such questions on the mechanics of
the event as:
To what extent is wet contaminant formed by condensation
Phenomena? With what type of particles do the primary particles of
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