Emitted by radionuclides

Energy production by nuclear fission and by thermonuclear reactions has been discussed in chapter 11. In this section, energy production in radionuclide batteries by the radiation emitted by radionuclides will be considered. 

Radionuclides have practical uses because they decay at known rates. Some applications make use of the radiation that is continuously emitted by radionuclides. 

Because the compilations are used for various nuclear physics purposes, much of the recently published information is far more extensive than needed by the radioanalytical chemist. Notably, information on numerous radiations emitted by radionuclides at less than 1 % wastes the time of the analyst who wishes to identify a radionuclide by one or two major radiations. Detailed information on radiations of minor intensity becomes useful only when these radiations affect measurement results for the characteristic radiations or lead to misidentiflcation. 

If the decay of peaks in the gamma-ray spectium is observable, the half-lives associated with these peaks are estimated and compared to tabulated values to confirm identification by energy. Gamma-ray peaks that appear constant are considered to be emitted by radionuclides that have half-lives long compared to the observation period. 

Wakat, M. A. 1971. Catalogue of y-rays emitted by radionuclides. Nucl Data Tables 8, 445-666. 

Radioactive substances (radionuclides) are known health hazards that emit energetic waves and/or particles that can cause both carcinogenic and noncarcinogenic health effects. Radionuclides pose unique threats to source water supplies and chemical processing, storage, or distribution systems because radiation emitted from radionuclides in chemical or industrial waste systems can affect individuals through several pathways by direct contact with, ingestion or inhalation of, or external exposure to, the contaminated waste stream. While radiation can occur naturally in some cases due to the decay of some minerals, intentional and nonintentional releases of... 

Photons with detectable energy differences that are emitted by various radionuclides can be quantified simultaneously, but independently from each other. This allows the use of dual-labeling approaches (4). These experiments will reveal information regarding both the liposomal carrier—labeled with one radionuclide—and the encapsulated compound—labeled with a different radionuclide—after a single injection in the same animal. However,... 

Radioactivity is a form of energy emitted by radioactive elements (radioisotopes or radionuclides). Radionuclides can present a health threat to humans and marine organisms because of the ionizing ability of the emitted radiation. The major pathway by which marine organisms and humans are exposed to radionuclides comes from consumption of fish and shellfish due to bioaccumulation of °Po and °Pb. Most of the °Po and Pb in the ocean is natural, but, human activities have increased their inputs to the coastal ocean. 

This definition is based on the source of the waste, but certain incidental wastes that arise from fuel reprocessing that contain lower concentrations of fission products and alpha-emitting transuranium radionuclides than the primary reprocessing wastes have been excluded on a case-by-case basis. 

Transuranic waste. As described in Section 4.1.2.2.2, transuranic waste originally was defined by AEC as solid waste that contains long-lived, alpha-emitting transuranium radionuclides or 233U in concentrations greater than 0.4 kBq g A Transuranic waste so defined was not generally acceptable for shallow-land burial. 

In addition to specifying the lower limit on concentrations of alpha-emitting transuranium radionuclides, this definition specifies their minimum half-life. In contrast to the earliest definition developed by AEC, this definition does not include waste that contains high concentrations of long-lived, alpha-emitting non-transuranium radionuclides (e.g., 233U). 

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