Evening star., 1952-04-07
Atom Waste Products
May SteriIize Foods
Two Such Isotopes Seem
To Have SpecioI Value
By Thomos R. Henry

10 HoVe SPeCIoI VuIue
By Thomos R. Henry
Waste products from the production
Of plutonium. basic material of atom
bombs. may have vital roles in purify
ing foods and medicines.
At present they are dangerous wastes,
the disposal Of which Is q major prob.
lem In the atomic energy program.
An extensive study carried out at the
Stanford Research Institute in Cali
fornia, an Atomic Energy Commission
project. indicates that these present-day
nuisances may become valuable assets.
These products are the exploding
atoms Of a variety Of elements produced
in the splitting of uranium 235 atoms,
the start of the plutonium- making pro-
cess. Some remain explosive. or radio
active, only fractions of seconds while
some remain alive for millions Of years.
A few have found limited application
in medicine.
Two With Special Significance.
The new uses. which may call eventu-
ally for enormous quantities, are pri-
marily in sterilization Of products and
in the production Of phosphors, the
luminous materials on the dials Of radi-
ant watches and on road signs. Two Of
the now waste products seem to have a
special significance, strontium 80 and
cesium 1877. Both are rare, light, silvery
metals. The strontium emits beta par
ticles, or electrons, with energy OF
slightly over half million volts. 1t has
q half-life-the period during which half
the atoms Of any given mass will have
disintegrated-of Is years. Cesium 1877
also emits half -million-volt beta par
ticles. 1t has half-life Of 33 years. The
half-life time is Of particular impor-
tance for it determines the time the
materials can be kept in storage and
remain available for industrial pro-
cesseS. Obviously a radioactive material
whose half-life was only few minutes,
or hours, could neither be stored or
transported.
Everything depends, the Stanford
scientists report on the price at which
these isotopes can be separated and
sold to industry, in competition with
X-ray machines, heat and other means
of sterilization.
Would Sterilize Ham.
Cesium 1877, for example, emits at one
stage in its disintegration half-million-
volt gamma rays. that Is, extremely
short and penetrating X-rays. A con-
siderable part of the cost Of penicillin
production is due to the necessity OF
sterilization with X-rays. This could
be done about as well with the cesium
iSotope If the price can be cut to about
81 per curie "a curie is the amount Of
radiation obtained from a gram OF
radium). A demand for about 100000
curies a year Is estimated.
Sterilization of canned ham also would
be commercially feasible, the report
says. If the cost Of cesium 1877 could be
cut to 20 cents q curie-a goal which
seems attainable. Perhaps the biggest
demand of all, it Is reported, would be
for the sterilization of canned peaS-in
excess of 400,000,000 curies a year.
Strontium 80 now sells for $500 per
curie and is used primarily to activate
phosphorescent substances for watch
dials and the like. If the price could
be reduced to $50, it was found, there
would be a probable demand for the
equivalent of 10000 CT. les year.
Others of the SO or more radioactive
by-products of plutoAium production,
it is pointed out, probably have uses
which are not so obvious at present.
A fool-proof "dog-tag" detector Of
killing radiation, such as would attend
an atomic bomb explosion, has been de-
vised at the Naval Medical Research
Institute here.
It is worn around the neck like q
dog-tag, weighs only about an ounce,
hoc ov,ie n%
be read by anybody.
This detector is baSically q specially
treated crystal of potassium bromide
one Of the so-called alkali halides,
another example Of which is table salt.
Such a crystal changes color when
gamma rays or X-rays fall on it. Com
mon salt, for example, would tend to
become amber.
A potassium bromide crystal turns
blue. The greater the radiation to which
it is exposed the bluer it becomes These
particular crystals, however, are given
a special treatment with metallic
potassium vapor and hydrogen which
increases their sensitivity about forty
fold.
Arranged around the tiny crystal are
equally tiny squares Of different blue
matches that Of one of these squares
it indicates that q certain degree Of
radiation has been received
Some Devices Intricate.
Many radiation detection devices have
been reported in the past few years
but most of them are somewhat COM
plicated. Some require counting the
clicks" of the Geiger counter. Others
require electric Set-ups which are COM
plicated and likely to be too heavy for
comfort. They also are likely to be out
of order in an emergency. Some require
an expert to read.
The Navy researchers both at the
Medical Research Institute, Bethesda.
and Research Laboratory Anacostia.
recognized from the first that adding
to the ever-increasing burden which a
sailor or soldier must carry is especially
to be avoided. These devices weigh
hardly as much as a dog tag.
Research is continuing on this type
of detector with the object of decreas-
ing both weight and cost so that the
instruments can be distributed to every
body in any danger Of being exposed
to radiation.
Once one of these tiny crystals has
been activated 1t will remain effective