Industrial Use of Nuclear Technology
Did you know that you don't have to be a nuclear engineer or scientist to work with nuclear technology? The unique characteristics of nuclear materials have found application in many areas unrelated to the traditional nuclear fields. In particular, radioisotopes - either naturally or manufactured radioactive material - have found broad application in tools, gauges, and imaging machines. Such equipment has been used by a diverse range of occupations including law enforcement, the oil industry, archeologists, farmers and manufacturers of common consumer products. At the core of these applications is the radioisotope. Although radiation can't be seen, it can still be easily detected with the right instruments. Its penetrating nature and its unique detectability provide the real advantage of this technology.
Radioisotopes are used during manufacturing processes in a
number of different ways. One application is in gauging (measuring precisely).
Gauging works because radiation loses energy as it passes through substances.
This principle can be used to measure the presence or the absence of material
between the source and the detector.
Some machines, that manufacture plastic film use
radioisotope gauging to measure the thickness of the plastic film. The film
runs at high speed between a radioactive source and a detector. The
detector signal strength is used to control the plastic film thickness as it
is continuously made.
The height of the coal in a hopper can be determined
by placing high-energy radioactive sources at various heights along one side
with focusing collimators directing beams across the load. Detectors placed
opposite the sources register the breaking of the beam and, hence, the level
of coal in the hopper. A light beam could not do the same job in a very
● When the intensity of radiation from a radioisotope is reduced by matter in the beam, some radiation is scattered back towards the radiation source. The amount of 'backscattered' radiation is related to the amount of material in the beam, and this too can be used to measure characteristics of the material. This principle is used to measure different thicknesses of coatings.
application of radioisotopes in the manufacturing process is called
gamma-radiography. This process uses gamma-ray radioisotopes to test materials
for flaws such as invisible cracks, defects and occlusions in welds, etc. The
advantage of gamma radiography compared to non-nuclear technologies is that
gamma radiography can be done thoroughly and non-invasively (one does not have
to cut the material open), as well as more rapidly and cheaply. It can even be
done continuously as objects pass by on a conveyor belt.
Neutron Activation is a method of determining the
concentration of elements in a wide variety of samples, accurately and
precisely. It is another example of how radioisotopes can be used to help
scientists and researchers, and even criminal investigators. The method is
based on the detection and measurement of gamma rays, which have energies
characteristic of the sample under irradiation by neutrons.
Companies who process materials such as coal or
concrete use neutron activation to analyze the material for quality
Investigators, police, and other security groups use
neutron activation to detect explosives, such as mines, and to detect drugs
In medicine, and more specifically, in sports, neutron
activation is used to measure the human body composition to study the
workings of the human body
● The exploration industry will use neutron activation to explore ores, to find out what ores they encounter
Radioisotopes can also be used as tracers not just in
medicine, but also in industry. These radiotracers emit gamma rays and/or beta
particles that can be detected and measured by a variety of different counters
-- either in situ or from samples in labs. By proper analysis the quantity of
the tracer can be determined at any point in a pathway through which it is
traveling. The tracers used are specific to the use.
Mixing efficiency of industrial blenders can be
measured: radiotracers are added to various solutions that are to be mixed
together to allow the manufacturer to determine when his mixture has reached
Radiotracers are used to trace down sources of
pollution. For example, if one injects a known amount of radioactive tracer
at a source of pollution (say at an outflow from an industrial plant or even
a point of soil wash into a stream), its pathway downstream can be
identified. In this way, it might be found that the industrial plant was
the culprit for pollution washed ashore miles away, or (equally likely) that
that particular pollutant came from a different source. Similarly, looking
at soil washed into streams, it would be possible to determine which farmer
(or even which cows) where the culprits by using different tracers. In the
old days a colored dye might be used as an indicator, but no accurate
measurements could be taken.
Small leaks can be detected in complex systems such as
power station heat exchangers or oil pipelines in a refinery.
Flow rates of liquids and gases in pipelines can be
measured accurately, as can the flow rates of large rivers.
The extent of termite infestation in a structure can
be found by feeding the insects radioactive wood substitute, then measuring
the extent of the radioactivity spread by the insects. This measurement can
be made without damaging any structure as the radiation is easily detected
through building materials.
Using tracers, research is conducted to examine the
impact of human activities. The age of water obtained from underground
bores can be estimated from the level of naturally occurring radioisotopes
in the water. This information can indicate if groundwater is being used
faster than it is being replenished. Tracer radioactive fallout from
nuclear weapons' testing in the 1950s and 1960s is now being used to measure
soil movement and degradation. This is assuming greater importance in
environmental studies of the impact of agriculture.
Radioisotopes are used to test material parts and
products such as metals, tire rubber, and engine oil for wear.
Radioisotopes are added to these products, and then with the use of
sensitive radiation detectors, the location and amount of wear of these
products is determined. These tests help the manufacturer to produce the
best quality and most reliable products.
● In agricultural laboratories, radioisotopes are used to determine how plants take up nutritional materials or fertilizers to improve the efficiency. In the past, the improvement of plant species took several plant generation times as those with good characteristics (say, disease resistance, or nutritional value, or smell -- in herbs) were weeded out and propagated in favor of those with poor characteristics. Now by use of radioactive labeling, it is possible to shorten the time considerably and even arrange that a plant be generated with all the desirable characteristics (both disease resistance and oil flavor in the case of the peppermint plant).
Archeologists determine dates of samples, that were once alive (e.g. in bone, charcoal, leather) by a technique called "radiocarbon dating", so called because this method of scientific dating relies on the carbon-14 isotope. Carbon-14 is a naturally occurring, long-lived radioisotope that is present in all living things. All living things contain carbon, a proportion of which is radioactive C-14. As living organisms take up natural radiocarbon along with other carbon atoms, the ratio between the two forms remains constant. However, when they die, the radiocarbon decays and is not replaced. Since it decays at a known constant rate, the decreasing concentration of C-14 can be measured and the date when the material died estimated. Two classic applications of C-14 dating are the determination of the age of the Dead Sea Scrolls as about 2000 years, and the proof that the Shroud of Turin was made in the 14th Century.
Radioisotopes are used in a number of consumer products, so much so, that probably not a day goes by, without you having run into some consumer product that relied on some radioisotope application. Indeed they are now vital to industry. Here are a few examples:
Smoke detectors - a smoke detector contains a small
amount of americium-241 in the sensing unit that triggers the alarm when
there is smoke
Soft drink bottles - radioisotopes are used to measure
and control how much soda there is in soft drink bottles
● Shrink wrap film/plastic insulation on wires -- the plastic is shrunk by radiation instead of using heat, which damages the insulation
Faster, less expensive and thorough results -- When we wanted to identify material or check the quality of material in the past, we either had to do a chemical analysis of the material, which is a very slow process, or we had to do a sample destructive analysis of the material quality (destroy the material), which was very expensive. For example, In determining whether a casting is whole and there are no occlusions (holes) within it, or at least there are only small numbers, castings had to be sampled and cut open. All you could find out was whether the casting you had just destroyed was okay or not. It was an act of faith to say that the other castings were okay. Sampling is a little better than an act of faith if the process that produced the castings was carefully controlled, of course. Then you have a better chance that a sample is representative of the rest. However, these methods of testing materials or quality were always batch processes. They were not continuous. Today, thanks to nuclear science and technology we can analyze materials thoroughly and continuously, with less expenses and much faster.
Safety always comes first, for all types of applications of nuclear science and technology, including industrial applications. This is done through a number of ways:
The operator is kept away from the beam by simply
shutting off the machine whenever a violation (say of entry into the space)
There is no residual radioactivity in the tested
materials. Much the same safety measures that might apply to a mechanical
saw would be used on a neutron generator. However, sources are more
difficult since they are continuously and strongly radioactive. They emit
radioactivity all the time and, therefore, must be carried in containers,
which shield the operator from the radioactivity. Interlocks are used to
avoid humans entering the working area when the source is exposed. Usually
the casing also has a shutter, which can be opened for the neutron stream.
These shutters can be remotely operated. Sealed sources are stored in
shielded containers when they are not used.
After use, when the source has decayed some, it is
also necessary to carefully dispose of the source at a licensed disposal
site. However, there have been cases of accidents in both systems over the
years. In Mexico, an operator entered an accelerator room before it was
shut off. In Brazil and recently in Malaysia, sources were not disposed off
correctly. They were stolen and treated by the thief as nice scrap metal
with resulting exposure of a number of people. This is why careful
regulation is important.
Tracers are custom made for specific jobs so that
their activity will last for the length of the job but be of no concern
afterwards. Just as a person leaving hospital after a procedure in which
radioactive isotope has been used may be slightly radioactive for the next
day or so, it quickly decays -- so too no radiation is left in the
environment above background levels.
● In the laboratory, under controlled conditions it is possible that some gloves, swabs, syringes, even some test plants might be treated as low-level waste for disposal.