Industry is one of the fields in which nuclear energy is used. The use of nuclear energy in modern industry in developed countries is very important in different fields:
- Improvement of industrial processes.
- Quality control of raw materials for industrial processes (cement plants, thermal power plants, oil refineries, etc.).
- Quality control of mass-produced products
In the case of serial manufacturing it is used as a prerequisite for the complete automation of high-speed production lines.
In the industrial field, irradiation with intense sources is frequently used to improve the quality of certain products (special plastics, sterilization of single-use products, etc.).
In addition, tracer experiments are also carried out to obtain exact and detailed information on the state of industrial equipment to enable it to extend its useful life.
Nuclear sources for industrial use do not usually produce radioactive waste in the country that uses them, but in the supplier's country. Once these sources are useless, the commercial firm of the supplying country withdraws them when they are replaced.
Use of Radioisotopes as Tracers
The fact that small amounts of radioactive substances can be measured quickly and accurately means that radioisotopes are used to follow processes or to analyze the characteristics of those processes. These substances are called tracers.
Tracers are radioactive substances that are introduced into a certain industrial process. This action allows detecting the trajectory of these substances thanks to their radioactive emission. In this way, it is possible to investigate various variables of the industrial process (flows, leaks, leaks, etc.).
Some of the industrial applications of nuclear energy in which tracers are used are the following:
- Investigation of processes, being able to control the parameters of ventilation systems (flow rates, ventilation efficiency)
- For mixtures, checking the degree of homogeneity, the mixing time and the performance of the mixer
- Industrial maintenance processes, studying the transport of materials through pipelines (leaks or leaks and flows)
- Detection of wear and corrosion, determining the degree of wear of materials (motors) and the corrosion of processing equipment.
A tracer isotope is used in the field of chemistry and biochemistry to help understand chemical reactions and interactions. In this technique, one or more atoms of the molecule of interest are replaced by an atom of the same chemical element, but of a different isotope (the atomic nucleus is the same, but has a different number of neutrons).
Since the substitute atom has the same number of protons, it will behave almost the same way as the original atom and, with few exceptions, it will not interfere with the reaction to be investigated. However, the difference in the number of neutrons implies that it will be possible to detect it in a different way than the other atoms of the same element.
What Is Quality Control by Scintigraphy?
Gamma radiography is an application of nuclear energy in industry. This application constitutes an indispensable quality control technique for the verification of pipe welds and for the detection of cracks in aircraft parts.
Industrial radiography allows volumetric tests to be performed on a material. The difference in thickness in each of the sections of a material causes a different penetration of the X or gamma radiation to which it is subjected.
To carry out this test, a penetrating nuclear radiation source is placed next to the material to be examined. On the other side is a radiation detector. In this way, a representative two-dimensional image of the piece is obtained.
Radiographic interpretation consists of the analysis of the images obtained by means of industrial radiography, in order to detect and evaluate possible defects in the materials inspected and thus ensure the required quality of said material or component inspected.
It is the most important application of the iridium-192 sources. The iridium-192 sources cover 95% of the non-destructive tests carried out in the quality control of foundry products, welds of metal constructions, etc. The rest of these controls are carried out with cobalt-60 sources (for large thicknesses, up to tens of centimeters of steel) or with tulio-170 (for small thicknesses, on the order of millimeters).
Use of Radiation in Other Industrial Processes
Gamma radiation ionizes matter and creates free radicals, which are the intermediate species for many chemical reactions. Once radiation (cobalt-60 sources) is applied to the monomers from which plastics are made, the formation of large polymer chains is induced. From here, if the irradiation of the material is continued, special plastics with a high degree of catenary crosslinking are formed, which considerably improves its properties as a thermal and electrical insulator. Thus, the degradation of some polymers induced by radiation, constitutes a useful property for certain types of packaging.
Nuclear power is also applied in the production of gamma radiation degraded polyvinyl chloride insulated wire and cables. The use of radiation in these products results in an increased resistance to thermal and chemical stress.
Another important product is radiation-degraded polyethylene foam. Polyethylene foam is used in thermal insulation, impact padding, flotation vests, and gamma radiation solidified wood and plastic composites.