Measurements and Industrial Analysis
Small Power Sources
Other Industrial Uses
Radiation is used widely throughout industry for various tasks including
quality control, maintenance work and assessment of the environment.
Maintenance is a vital part of industry.
For example, aircraft welding needs to be checked regularly for cracks
and other faults, as well as gas and oil pipelines.
The checking for cracks can be done using the radiation emitted by radioisotopes.
Using radioisotopes to check for cracks can be accomplished
with a technique called gamma radiography. It is similar to how
X-rays are used in hospitals to check for fractures and cracks in bones.
In this process, the patient places their arm in front of an X-ray source, and
the rays that penetrate through body tissue darken a photographic plate to reveal
any cracks in the bones of the arm, etc.
Similarly, gamma radiography involves placing a radiation source on one
side of the gas pipeline, and a photographic plate on the other. The radiation
that can pass through cracks will show up on the photographic plate. This
checking process could have been done using X-rays like in the hospital,
except there is a lot of equipment required for X-rays, whereas using
gamma radiography requires only a radiation source which can simply be a small
pellet of radioactive material. X-rays also require electricity, whereas
radioisotopes do not.
The exact process is done by taping a special photographic film over the weld or
suspected crack of
a pipeline. A pipe crawler carrying the sealed radiation source is then dispatched
down the pipe to the weld position. The field technician performing the check
then sends a remote control message to the crawler to tell it to expose the radiation.
When this happens, the radiation passes through any cracks that may exist, onto
the photographic film taped on the outside. This film is then developed and
checked for cracks or welding deterioration.
Some industrial machinery contains parts that have small amounts of radioactive materials.
This allows easy observation and detection of wear and tear. However, this practice
is not common because of public fears about the radiation.
Measurements and Industrial Analysis
Radioisotopes are commonly used for measuring viscosity, density and thickness
in conditions where other methods would be difficult or impossible to apply.
Since radiation does not require direct contact (unlike, for example, using a scale or tape-measure)
it is used where high heat or corrosive chemicals may exist.
Radiation is reduced in intensity when it passes through many materials.
Therefore the amount of stuff between a radiation detector and emitter can
be determined by calculating the difference between the intensity of
emitted radiation and the intensity of the received radiation.
This concept is applied in the manufacture of thin plastic films.
The produced film is passed through a radioisotope gauge - the thicker
the film, the lower the detected radiation. Changes in the detected level
of radiation correspond to a change in thickness of the plastic, so
this is a form of quality control.
(The decrease in intensity of visible light as opposed to radiation is used in many photoelectric
devices including some smoke detectors. However, light cannot be always used
to measure thickness of materials unlike radiation, because light is completly blocked
by opaque surfaces or completely transmitted by clear surfaces.)
Radioisotopes can also be used to calculate the efficiency of large
mixers, or the flow of materials through blast furnaces. Leaks and other
defects can also be detected in building cooling towers and power station heat exchangers.
Radioisotopes are used as power sources
for applications requiring small amounts of portable energy,
such as for remote weather stations and weather balloons, and navigation
beacons and buoys. They are more environmentally friendly than batteries
because once all the energy from radioactivity is used, there are few
left-over wastes except for the stable atoms formed, whereas used batteries will always
contain toxic heavy metals that are hazardous to the environment.
All substances that exist are likely to have radioactive atoms in them
occuring naturally. Water is an example of this. Underground bore water
in particular is likely to have radioactive minerals and gases present.
The rocks underground will often contain small amounts of radioactive elements
such as uranium. The decay of uranium will produce other radioactive elements,
and these may leak into the bore water.
The concentration of these radioactive elements in the water can be analysed
to determine whether the bore water deposits are being used faster than they
are being replenished, as well as the "age" of the water (how long
it has been untouched).
Ocean pollution can be analysed for radioactivity to trace the source
that caused it. Similarly, the dispersion of a known factory's pollutants
can be monitored this way.
The rate and extent of soil erosion can be determined through the use of
See the table below for a list of radioisotopes used in environmental monitoring
and other industrial processes. In general, it is the labelling property
of radioisotopes that allows them to be used in a wide range of environmental
Radiation is also used in determining the nature and extent
of termite infestation in buildings. This is done by feeding
the termites a sample of artificially synthesised radiactive wood.
The termites then disperse the radiation when they bury into the building
structures, and the spread of radiation is used to give an indication
of the nature of termite infestation. This process sometimes
is better than physically removing and examining parts of the building,
because the radiation can be detected easily through the building materials
without needing to dismantle anything.
list of some common radioisotopes used in industry
|hydrogen-3||water age measurement, study of sewage|
|carbon-14||water age measurement|
|chlorine-36||water age measurement|
|scandium-40||study of blast furnace efficiency|
|manganese-54||study of environmental impact of mining|
|chromium-57||study of coastal erosion|
|zinc-65||study of environmental impact of mining|
|caesium-137||soil erosion monitoring|
|iridium-192||study of coastal erosion, checking of aircraft welding faults|
|gold-198||study of sewage and sources of water pollution, monitoring of sand movements in ocean floors and river beds, coastal erosion, study of blast furnace efficiency|
|lead-210||soil and sand age measurement|
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