study the contamination-decontamination problems associated with
building construction materials subjected to wet contamination under
field conditions reasonably equivalent to those which would be
produced by the detonation of a nuclear weapon in a harbor or in
shellow coastal waters ,
While CROSSROADS yielded some information relative to the
contaminability of surfaces, no systematic study of these effects or
of specific decontamination techniques was conducted.1,2 Decontami- nation efforts were of an emergency nature only.3 On the other hand,
at Operation GREENHOUSE, some effort was made to study contamination
effects by mounting small-scale pansls of a limited variety of
construction material surfaces on the wings of drone aircraft which
were flown througn the radioactive clouds of relatively high yield
fission detonations.4
It was found that the roughest surfaces became
contaminated to the highest levels and were the least responsive to
decontamination.
Surface parameters such as porosity, contact angle,
and dye retentivity appeared to be of lesser effect.
However, due to
the high impact velocity of the contaminant on these surfaces, the
contamination effects so obtained were not too realistic and were not,
therefore, of direct value in the developrent of practical recovery |
criteria,
An extension of the GREENHOUSE studies was conducted at JANGLE
where similar panels, but of larger scale, were exposed to the fallout
from a shallow underground detonation.?
While the roughest surfaces
again became more highly contaminated, the czy, powder-like contaminant
was loosely adherent and could be removed readily with water.
Candidate RW agents of the dry particulate type, during tests
conducted at the Arny Chemical Center® have exhibited similar
decontamination chéracteristics as JANGLE contaminants. The effect of
surface slope was such that horizontal surfaces retained from five to
three hundred times the activity retained on vertical surfaces,
1.3
BASIC THEORY
At CASTLE, it was anticipated that the contaminant would.
consist of liquid droplets containing fission products, bomb debris,
and other debris depending on the detonation ground zero environment,
In the case of barge detonation over shallow water, it was believed
that iron from the barge and calcium carbonate bottom material would
be in the fallout.
From a land surface detonation, larger percentages
of calcium carbonate from the island soil would be present. It was
believed that most of this debris would arrive as calcium hydroxide
resulting from the hydration of calcium oxide which was formed by
the heat of the detonation from the original caleium carbonate, 38
These particles would have a calcium carbonate suface layer.
Subsequent wetting of deposited fallout particles by sea water was
believed to produce outer layers of precipitated magnesium hydroxide,
hydrated calcium sulfate, and calcium carbonate.‘
Experimental
evidence indicated that this form of ccntaminant would be extremely
retentive,
The Stanford Reseerch Institute, under Chemical Corps contract,
has deduced from available data that the average type of wet clay
12
CONFIDENTIAL —~ RESTRICTED DATA