1. INTRODUCTION
The considerable work on the mechanism of formation and properties
of fallout has used data from Pacific Ocean events (coral island or sea
water emplacement) and from excavation exper iments (Fr70, K164).
However, about 90% of the Nevada and Utah population's exposure to
radioactive fallout from nuclear weapons testing in Nevada during the
years 1951 through 1957 was due to 16 devices (An81) detonated on steel
towers 300-700 feet above the ground.
No data from shots emplaced on
steel towers at the Nevada Test Site have been compared to the accepted
model because the only data extant were taken for another reason, i.e.,
to study the uptake of radionuclides by animals living in the fallout
pattern (La66).
Only some of the data were reported, thus preventing
their use in checking the fallout model or these calculations.
The
Nevada Operations Office of the U.S. Department of Energy has recently
acquired the laboratory notebooks containing more of the data.
This
work describes the comparison of all these data with results derived
from the fallout composition model.
In this work I have developed a method to calculate the ground
concentration (uCi/m?) of each radionuclide from the external gamma
exposure rate given by the fallout pattern.
fractionation are included.
The effects of
The results are compared with field data
and interpreted according to the accepted model of fallout formation
(Ad60).
The calculations agree in detail with the field data; thus,
the fractionation behavior of offsite fallout from tower shots within
160 miles of ground zero is well characterized.
Uranium and plutonium