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Radiation and man
Published in R.J. Pentreath, Nuclear Power, Man and the Environment, 2019
In order to calculate the impact, and thus recommend a permissible rate of intake, of a radionuclide, it is therefore necessary to compile a number of relevant data. With regard to the radionuclide, its type of emitted radiation (α, β, y), the energy of the radiation, and its physical half-life and decay scheme are all relevant. Of the biological data required, it is usually necessary to determine that fraction of the radionuclide – inhaled or ingested – which is actually assimilated, the particular organs in which it may become concentrated, the ratio of any such concentration to that of the whole-body content, and the rate at which the radionuclide may be execreted, both from a particular organ and from the body as a whole. It has, in fact, as was mentioned above, been customary to recognize a particular part of the body which, for a given radionuclide, is of the greatest importance on account of the dose that it receives, its sensitivity to radiation, and the importance to health of any damage that results. Where definable, this organ (or organs) has been termed the critical organ.
Nuclei and Radiations
Published in José Guillermo Sánchez León, ® Beyond Mathematics, 2017
The command below returns the decay scheme of 14C. It decays into 14N with a beta emission (1 electron) and has a half-life period of 1.8 × 1011 s (approximately 5,700 years) c14 = IsotopeData["C14", #] & /@ {"DaughterNuclides", "BranchingRatios", "DecayModes", "HalfLife"}
Coupled Neutron and Gamma Heating Calculation Based on VARIANT Transport Solutions
Published in Nuclear Science and Engineering, 2019
P. Deng, B. K. Jeon, H. Park, W. S. Yang
Although the ENDF/B VII.1 sublibraries provide the decay data for all fission products, the relatively recently compiled JENDL decay data were used in this study. The JENDL decay data were compiled in 2011 with the fission-product decay data file. To match the average beta and gamma decay energies with their spectral data, the JENDL decay data use the theoretically calculated spectra and the total absorption gamma-ray spectroscopy, or TAGS, data for the nuclides with incomplete decay scheme.27,28 The delayed gamma energies estimated with the JENDL libraries showed better accuracies than those values derived from the fission yield and decay data of the ENDF/B-VII.1 library.24
Beta-Ray-Bremsstrahlung Contributions to Short-Lived Delayed Photoneutron Groups in Heavy Water Reactors
Published in Nuclear Science and Engineering, 2023
Yanuar Ady Setiawan, Hemantika Sengar, Douglas A. Fynan, Arief Rahman Hakim
Table II summarizes the top 85 precursors contributing over 99% of the PNs from beta-ray bremsstrahlung for the CANDU fuel element geometry. The precursors are ranked in descending order of the total PN yield from beta-ray bremsstrahlung per fission , which is Eq. (2) tabulated in column six multiplied by the cumulative fission yield χc from the thermal fission of 235U, noting that the saturation activity of a radioactive fission product is usually χc times the total fission rate in the reactor. Unless otherwise noted, the radioactive decay data were obtained through an automated digital search of the 3820 isotopes listed in the radioactive decay data ACE file of ENDF-VII.1 (Ref. 23). Excluded are radioactive activation products that are not fission products and an additional 196 fission products with listed beta-decay-scheme data and at least one beta-decay endpoint energy above 2.2259 MeV but the is less than . Appended to Table II are precursors with low 235U χc but with PN yield from beta-ray bremsstrahlung greater than per decay and several very-long-lived precursors of interest. In ongoing work,18 we have identified over 250 PN precursors with a PN signature from discrete gamma rays. Table II includes many precursors that produce PNs from both gamma rays and beta-ray bremsstrahlung quantified by percent of total PNs originating from bremsstrahlung (Beta Contribution) tabulated in the seventh column. Excluded from Table II are precursors that produce PNs from gamma rays only. A precursor with zero entry in column seven indicates the magnitude of the beta-ray-bremsstrahlung PN signature contributes to the background of a relatively large gamma-ray PN yield. Table II lists 23 precursors with 100% beta-ray-bremsstrahlung PN yield, including some high-fission-yielding metastable states of short-lived isotopes.