found in ae #3 and #4 indicates - the radexes prepared
using the actual winds three hours.before shot time, delineate the
general fall-out area adequately.
In Mygures 1 through 9 the radex
plots based on the H-3 and H-< hour actual winds are superimposed on
the actual fall-out area.
A study of these figures shows clearly that
radex plots based on the actual winds near shot time delineate the fall-
out area adequately.
The area of maximum intensity of fall-out could
be located by this method within an averages angular displacement of
roll
plus or minus five degrees,
The angular displacement of the center of
the maximimfall-out area does not show a displacement greater than 15
degrees.
Considering that the :inds are four hours old in these radex
plots, it becomes at once evident that there is considerable persistence
to the winds.
Certainly if the decision to fire a potentially contamin-
ating shot is delayed until the last two or three hours, it is difficult
to see how larce errors could be made in the radex plots,
Fortunately
onan i
it appears that the simple Stokes’ Law assumptions are valid for 70 to
150 micron particles, which are the main cause of the radioactive con-
cinattaeeittinatmriat ination, tpilbeesinateinies
tamination within 200 miles of the domestic test site at the Nevada
Proving Grounds,
B,
Verification of Radioactive Fall-out Forecasts
After the writer had analyzed the fall-out from TUMBLER/
SNAPPER (R) tower shots it was possible to forecast tha‘: 10 to 15 XT
bombs detonated from 300 ft towers would produce § to 2 roentgen life
time doses within the populated areas in the periphery of the Nevada
Test Site,
This information was made a matter of record and called to
,eo4
UNCLASSIFIED
nal ae
tae
C3-3
~~
- anole
>
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