ATOMIC ENERGY IN INDUSTRY—WINNE 
INDUSTRIAL USE OF RADIOACTIVITY 
The prime characteristics of radio- 
active tracers which make them of 
value are two. First, extremely small 
quantities can be detected by register- 
ing the particles or radiations emitted 
at each disintegration on a suitable 
radiation-detection instrument. Sec- 
ond, by the same means it is possible 
to detect and to measure the amount 
of tracer present quite accurately 
without removing it from the com- 
pound by chemical separation or even 
without removing or sampling the 
compound from its process container. 
Perhaps the surest widespread in- 
dustrial uses are in the chemical 
laboratories. Because chemically and 
physically the radioactive isotope of 
an element acts exactly the same as the 
stable isotope of the same element, 
analytical techniques can determine 
the amount of a given element in the 
final product or at an intermediate 
stage if a known amount of radio- 
active isotope of that element is added 
to the bulk at the start. This can be 
of value when quantitative analysis or 
spectrographic methods cannot be 
used. 
Some of the scientific advice given 
to the United Nations Atomic Energy 
Commission by the Office of the 
United States Representative, which 
has not received wide national circu- 
lation, is quoted (3): 
The availability of a variety of radioactive 
tracer elements will afford possibilities for 
answering questions hitherto difficult to 
answer. By the use of instruments sensitive 
to radioactivity, the radioactive atoms of a 
given element, which always travel with 
their nonradioactive brothers, may be used 
as indicators of the travel of the latter, a 
phenomenon often difficult to follow by ordi- 
nary methods. Particularly important are 
questions as to how, and how fast, atoms 
transfer from one molecule to another or 
from one place to another in the course of a 
chemical process, including such processes as 
corrosion, diffusion, absorption of molecules 
on surfaces, and formation and destruction 
of colloids. 
The use of radioactive tracer atoms holds 
much promise for the study of the composi- 
tion of liquids and vapors in equilibrium 
with each other, and for studying the per- 
185 
formance of distillation columns and other 
equipment used in chemical engineering, for 
example, in the oil industry. Particularly 
important as a tracer in the oil industry and 
wherever carbon compounds are concerned 
will be the carbon isotope C14. 
The radiations from the fission chain re- 
action are capable of inducing chemical 
reactions which cannot ordinarily be carried 
out, since one effect of radiation is a sort of 
catalysis of thermodynamically possible 
reactions. 
METALLURGY 
In metallurgy, the use of radioactive tracers 
has many possible applications. Some of 
these are as follows: 
1. Diffusion of an element into itself and 
into alloys in which it is a component could 
be followed if the diffusing atoms are radio- 
active. 
2. Inclusions could be identified by adding 
a radioactive form of a suspected component 
to the melt and photographing by micro- 
radiographic techniques. 
3. Positive identification and location of 
minor constituents, which often markedly 
affect the properties of metals and alloys, 
could be made by microradiographic meth- 
ods; such information is usually very difficult 
to obtain by microscopic methods. 
The previous discussion has envis- 
aged adding the radioactive tracer to 
the material. A very different analyt- 
ical technique is based on producing 
radioactivity in all susceptible ele- 
ments of a sample by subjecting the 
sample to a known amount of radia- 
tion in the neutron flux of a pile. 
Then the presence of minute traces of 
impurities can be identified by observ- 
ing the half-lives and type of radio- 
active emanations after removal from 
the pile. The amount of impurity 
also can be estimated. 
Tracers may find widespread use in 
production processes. Here, however, 
additional limitations enter. Cost in 
repetitive use becomes more signifi- 
cant. The Carnegie Endowment Com- 
mittee on Atomic Energy (2) esti- 
mated that for radioactive carbon 
(C14) to be attractive to industry, it 
should be produced at about $500 
per gram to reach mass use in petro- 
leum, coal tar, and similar large- 
volume production. This assumed 
that a milligram (50 cents) could tag 
a ton of material at an additional cost 
of 50 cents for incorporating the tracer 
