Radioactivity useful applications

It is the purpose of this book to present the facts about the presence of radionuclides in nature. The use of technology can significantly modify the exposure to natural radiation. Among the human activities which should be considered in this context are (i) the electricity generation by coal-fired power plants, (ii) the use of phosphate fertilizers, and (iii) many consumer products. Man-made radioactivity has found many useful applications in everyday life. The best known are medical applications. The use of radionuclides and radioactivity in diagnosis and treatment of diseases is well established practice. 

Thorium, discovered by Berzelius in 1828, is. teresting scientifically by roason of its radioactivity. has found no useful application as a metal, but its ride, thoria, has proved invaluable to the gas. dustry, being used for the manufacture of incan-... 

Among the technetium isotopes, only " Tc, a pure emitter ( ,nax=0.29 McV) with a half-life of 213 000 a, can be obtained (Sect. 5.1) in amounts adequate for studying the technical applicability of the element and its compounds. However, the widespread use of technetium is necessarily restricted by its radioactivity. The application of the metastable isotope Tc in nuclear medicine has quite superior significance and will be described in detail in Part B. 

What are some of the useful applications of radioactive isotopes, including energy production ... 

One form of radiation therapy is isotope therapy, in which a labeled substance that is known to accumulate in the defective organ is introduced into the body. The radiopharmaceutical may be a compound labeled with radioactivity or a radioactive isotope that has the tendency to accumulate. The most-used application of isotope therapy is the use of radioactive iodine I to treat hyperthyroidism and cancer of the thyroid. The rest of the treatments are covered by treatment of blood illnesses with compounds containing radioactive phosphorus or the treatment of joints with the yttrium isotope... 

A useful application of half-lives is radioactive dating. No, radioactive dating has nothing to do with taking an X-ray tech to the movies. It has to do with figuring out the age of ancient things. 

Nuclear processes provide humankind with a double-edged sword. On one hand, there are many useful applications of radioactive substances in science and medicine. Nuclear power is, and will continue to be, an important soiuce of energy. On the other hand, there is always the danger of radioactive or fissile materials being used to threaten people s lives. No one can make radioactive or fissile materials just go away. Hopefully, wisdom will prevail, and peaceful applications of nuclear materials will dominate their use. 

A useful application of hcdf-lives is radioactive dating. Carbon-14 (C-14), a radioactive isotope of carbon, is produced in the upper atmosphere by cosmic radiation. The primary carbon-containing compound in the atmosphere is carbon dioxide, and a very small amount of carbon dioxide contains C-14. Plants absorb C-14 during photosynthesis, so C-14 is incorporated into the cellular structure of plants. Plants are then eaten by animals, making C-14 a part of the cellular structure of all living things. 

Cerium is a component of misch metal, which is extensively used in the manufacture of pyrophoric alloys for cigarette lighters. While cerium is not radioactive, the impure commercial grade may contain traces of thorium, which is radioactive. The oxide is an important constituent of incandescent gas mantles and is emerging as a hydrocarbon catalyst in self cleaning ovens. In this application it can be incorporated into oven walls to prevent the collection of cooking residues. 

Three common quantitative applications of radiochemical methods of analysis are considered in this section the direct analysis of radioactive isotopes by measuring their rate of disintegration, neutron activation, and the use of radioactive isotopes as tracers in isotope dilution. 

One example of a characterization application is the determination of a sample s age based on the kinetics for the decay of a radioactive isotope present in the sample. The most common example is carbon-14 dating, which is used to determine the age of natural organic materials. 

Many artificial (likely radioactive) isotopes can be created through nuclear reactions. Radioactive isotopes of iodine are used in medicine, while isotopes of plutonium are used in making atomic bombs. In many analytical applications, the ratio of occurrence of the isotopes is important. For example, it may be important to know the exact ratio of the abundances (relative amounts) of the isotopes 1, 2, and 3 in hydrogen. Such knowledge can be obtained through a mass spectrometric measurement of the isotope abundance ratio. 

Decay products of the principal radionuclides used in tracer technology (see Table 1) are not themselves radioactive. Therefore, the primary decomposition events of isotopes in molecules labeled with only one radionuclide / molecule result in unlabeled impurities at a rate proportional to the half-life of the isotope. Eor and H, impurities arising from the decay process are in relatively small amounts. Eor the shorter half-life isotopes the relative amounts of these impurities caused by primary decomposition are larger, but usually not problematic because they are not radioactive and do not interfere with the application of the tracer compounds. Eor multilabeled tritiated compounds the rate of accumulation of labeled impurities owing to tritium decay can be significant. This increases with the number of radioactive atoms per molecule. 

The abundance of a trace element is often too small to be accurately quantihed using conventional analytical methods such as ion chromatography or mass spectrometry. It is possible, however, to precisely determine very low concentrations of a constituent by measuring its radioactive decay properties. In order to understand how U-Th series radionuclides can provide such low-level tracer information, a brief review of the basic principles of radioactive decay and the application of these radionuclides as geochronological tools is useful. " The U-Th decay series together consist of 36 radionuclides that are isotopes (same atomic number, Z, different atomic mass, M) of 10 distinct elements (Figure 1). Some of these are very short-lived (tj j 1 -nd are thus not directly useful as marine tracers. It is the other radioisotopes with half-lives greater than 1 day that are most useful and are the focus of this chapter. 

The diffusion coefficients of cations in metal oxides are usually measured through the use of radioactive isotopes. Because of the friable nature of oxides it is exU emely difficult to use the sectioning technique employed for metal samples. The need for this can be avoided by the application of radioisotopes which emit radiation having a well established absorption law in matter. Isotopes which emit y radiation are very useful when the cation has a relatively high diffusion coefficient because of the long-range peneU ation of y rays. The absorption law is... 

Applicability Limitation Vitrification was originally tested as a means of solidification/immobilization of low level radioactive materials. It may also be useful for forming barrier walls. This latter use needs testing and evaluation to determine how uniform the wall would be and to evaluate the stability of the material over a period of time. 

The price per m of the other noble gases is considerably higher (Ne 70, Kr 350 and Xe 3500, and this tends to restrict their usage to specialist applications only. Radon has been used in the treatment of cancer and as a radioactive source in testing metal castings but, because of its short half-life (3.824 days) it has been superseded by more convenient materials. Such small quantities as are required are obtained as a decay product of Ra (1 g of which yields 0.64 cm in 30 days). 

Radioactivity The ability possessed by some natural and synthetic isotopes to undergo nuclear transformation to other isotopes, 513 applications, 516-518 biological effects, 528-529 bombardment reactions, 514-516 diagnostic uses, 516t discovery of, 517 modes of decay, 513-514 nuclear stability and, 29-30 rate of decay, 518-520,531q Radium, 521-522 Radon, 528 Ramsay, William, 190 Random polymer 613-614 Randomness factor, 452-453 Raoult s law A relation between the vapor pressure (P) of a component of a solution and that of the pure component (P°) at the same temperature P — XP°, where X is the mole fraction, 268... 

---