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Political and Regulatory Aspects of Energy and Environment
Published in Anco S. Blazev, Power Generation and the Environment, 2021
NOTE: The half-life of a radioactive isotope is the time it takes for half of the isotope to decay, that is to give off radiation and change into a different isotope. The two isotopes of uranium present in high-level nuclear wastes, uranium-235 and uranium-238, have half-lives of 713 million years and 4.5 billion years, respectively. Both pose a threat to human health for a long time after they have been removed from a reactor core.
Properties and Applications of Rare Earth Oxides, Alloys, and Compounds
Published in A. R. Jha, Deployment of Rare Earth Materials in Microware Devices, RF Transmitters, and Laser Systems, 2019
Research studies undertaken by the oxides reveal that certain rare earth oxides are best suited for specific commercial, military, and medical applications. Comprehensive research studies undertaken by the author on specific rare earth oxides indicate that thulium oxide and holmium oxide are best suited for infrared lasers. Radiation studies seem to indicate that gre ater radiation danger can be expected from the processed REEs than from the processed oxides. Mild radiation danger can be expected from rare earth isotopes, if they are not handled with extreme care. It should be mentioned that the radiation danger is strictly dependent on the half-life of the isotope. Doctors, nurses, and lab technicians must be familiar with the half-life of the rare earth isotopes, if they are using rare earth isotopes in medical treatment. This is absolutely essential to avoid irreversible health injury to the patient.
Radioactivity in Drinking Water
Published in Joseph Cotruvo, Drinking Water Quality and Contaminants Guidebook, 2019
Many natural elements have radioactive isotopes, e.g., potassium 39 is stable and potassium 40, which is 0.012 percent of natural potassium, is a beta emitter with a half-life of 1.248 million years. Carbon 12 and carbon 13 are stable and carbon 14 (0.0000000001 percent) has a half-life of 5,730 years. Carbon dating is accomplished by determining the amount of remaining C-14 present compared to total C and back calculating decay time based upon the known half-life.
Technetium-99m metastable radiochemistry for pharmaceutical applications: old chemistry for new products
Published in Journal of Coordination Chemistry, 2019
Bianca Costa, Derya Ilem-Özdemir, Ralph Santos-Oliveira
Due to its short half-life (6.03 h), the radiopharmaceutical synthesis should be completed within 30 min and the yield should be greater than 90%, as the injection of a mixture of different 99mTc species will decrease organ specificity and increase the dose of radiation in patients. As almost all radiopharmaceuticals are administered parenterally, their synthesis must be performed under sterile and apyrogenic conditions [27]. Its half-life is sufficient to allow preparation of the radiopharmaceutical and to obtain useful images without causing increased radiation burden to the patient. The monochromatic 140 keV photons are readily collected and quantified to give high spatial resolution images [28].
A new approach to radioactive waste self-burial using high penetrating radiation
Published in Journal of Nuclear Science and Technology, 2018
Rafael Arutunyan, Leonid Bolshov, Anton Shvedov
A serious problem for radioactive waste (RW) management in nuclear power engineering is the safe disposal of long-lived transuranium elements, the half-life of which reaches hundreds or more years. At present, the generation rate of transuranium elements to be buried is about 50 kg/GW·yr.