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AVAILABILITY OF SAMPLES
A large number of contacts were made with people and institutions that have
been or are still involved with the analysis or utilization of nuclear debris
to ascertain the existence and location of samples. AS we expected, the
results were disappointing. A rather considerable inventory still exists of
samples collected by aircraft at the weapons laboratories. A few selected
samples are still available at LFE Environmental.
Fallout collections are few
and far between. The principal reasons are that many of these fallout collections were used up in their entirety for analysis and that a number of samples
was discarded some years ago.
Some fallout samples are now under the control of the Nevada Operations Office.
These samples are mostly from Areas 11 and 13 ("Program 57") and have been
collected at distances greater than 1 mile from GZ. Some Roller Coaster
samples on planchets are availabie at LFE Environmental. About 200 fallout
samples from Shasta, Johnie Boy, Small Boy, and Sedan are located at Camp
Parks near Livermore, California. All these samples are well documented with
regard to shot location and collection method.
This documentation is still in
the possession of the original investigators.
In addition, a few as yet
nondescript samples may be available at Battelle-Northwest in Richland, Washington, and at the Ballistics Research Laboratory in Aberdeen, Maryland.* A
complete inventory of all available and relevant samples has not been made.
DISCUSSION
A large body of data has been generated on fallout as well as on clouds from
many events of different type that have contaminated the test sites.
Projects
were conducted independently, each having its own objectives and its own
experiments. As a Tesult, there was little correlation between experiments,
and very few review articles or reports in which results were put together and
critically examined.
Even data from different projects relating to single
shots often remained uncorrelated,
The correlation of data of similar type from different tests is difficult
because sample collection methods, analytical techniques, and data presentations
differed. Sometimes sample documentation was inadequate.
Cross-calibrations
were almost nonexistent.
Subjectivity in reporting was sometimes present, for
example, in the case of shape and color.
The reasons for data acquisition and the use to which data have been put are
quite varied. Emphasis has changed over the years, in part because people
were getting smarter, in part because requirements changed,
Data acquisition for the purpose of evaluation of device performance has
always occurred.
Such data are of limited use for today's needs for fallout
characterization.
In the early days, understanding particle and fallout
formation and the formation of radiological countermeasures were the prime
objectives for most of the projects, the former objective having persisted for
a long time. This particular objective was also sought in a number of projects
involving laboratory simulation of conditions under which fission products
would be incorporated in particles.
The definition of the fallout field and its properties was also of interest
for certain military applications, and became of interest to the Plowshare
program (Peaceful Use of Nuclear Explosives) for what today would be called
Environmental Impact Assessment.
Data were also generated, particularly
during the last ten years or so, to provide inputs to fallout models for model
verification and for predictive purposes.
Estimates of soil burdens in nuclear
clouds also result from these and similar activities.
Some data not separately discussed in this review were generated for the
purpose of evaluating effects from accidents; for example, data from the
Roller Coaster and Kiwi (nuclear propulsion reactor} tests.
Studies of the modes of entry of fallout or radtonuclides into the biosphere
have always provided an important impetus to the gathering of a variety of
data.
Solubility studies were certainly directed towards this purpose.
In
recent years, fallout-particle characterization studies also have increased
for use in such studies. Thus, hazard assessment, either of already contaminated
areas or in a predictive mode, has become the prime interest.
O£ particular interest at the present time is the characterization of the
radioactive fallout particles at the Nevada Test Site, especially with regard
to theie chemical and radiochemical properties. The plutonium and americium
content of the particles, the concentration as a function of the particle
size, the distribution within the particles, the chemical form, the “soiubility,"
are all of interest for the estimation of the redistribution of fallout (by
wind or mechanical action) and modes of entry into the biosphere. Many of the
data, once they are correlated, are directly applicable to the question of
fallout characterization.
However, plutonium, being an alpha emitter, waa
more or less fgnored during the earlier work. Nevertheless, useful inferences
may be made from what has been observed generally with regard to radionuclide
fractionation and some actual data that are available.
Making inferences with regard to transuranics concentrations and distributions,
although useful, is not wholly satisfactory. Requirements that have been laid
down or that may be formulated in the near future necessitate a more definitive
characterization of the transuranica-bearing particulates and their temporal
and chemical behavior in the environments in which they exist.
Such a characterization is by no means a trivial task.
Ideally, a physical separation of
these particulates from the soil particles is required.
This is a task which
*The BRL samples have now been transferred to LFE Environmental.
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