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Radionuclide Production
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
As seen in Figure 4.1 the radionuclides to the right of the stability line have an excess of neutrons compared to the stable elements, and they are preferably produced by irradiating a stable nuclide with neutrons. The radionuclides to the left are neutron deficient or have an excess of charge and, hence, they are mainly produced by irradiating stable elements by a charged particle. Although these are the main principles, there are exceptions.
Biokinetic Models
Published in Shaheen A. Dewji, Nolan E. Hertel, Advanced Radiation Protection Dosimetry, 2019
Radioactive decay results in emission of radiation and transformation of an atom, called the parent, into a different type of atom, called the progeny or daughter radionuclide. The progeny radionuclide may also be radioactive, in which case it will also eventually decay and emit radiation. This leads to a sequence of different radionuclides and decay events, eventually producing a stable nuclide. The parent radionuclide together with the sequential set of radionuclides produced by this process is called a decay chain. The members of a decay chain excluding the original parent radionuclide are referred to collectively as the radioactive progeny of that parent radionuclide.
Post-Neutron Mass Yield Distribution in the Thermal Neutron Induced Fission of 232U
Published in Nuclear Science and Engineering, 2022
H. Naik, R. J. Singh, W. Jang, S. P. Dange
It can be also seen from Figs. 3 and 4 that the YC value of 136I from the present work and the evaluated data from Ref. 31 are significantly lower than the other fission products. This difference can arise for some of the fission products having short half-lives and are away from the last member of the fission products of the same isobaric chain. Thus, the mass chain yield obtained from the cumulative yield will be higher than the cumulative yield, which is described in the next paragraph. Besides this, the next fission product 136Xe of the same isobaric chain is an even-Z stable nuclide with a spherical 82n shell and may have higher yield. Similarly, lower values for some of the short-lived fission products can be seen from Table I, which are not shown in Figs. 3 and 4 to avoid clumsiness. Instead of those, the cumulative yields of the fission products closer to the end of mass chains are shown in Figs. 3 and 4.
Integral experiment of 129I(n, γ) reaction using fast neutron source in the ‘YAYOI’ reactor
Published in Journal of Nuclear Science and Technology, 2021
Shoji Nakamura, Yosuke Toh, Atsushi Kimura, Yuichi Hatsukawa, Hideo Harada
The integral experiment was conducted by the neutron activation method. A simplified decay scheme of the 129I(n,γ)130m, 130gI reaction is drawn in Figure 3. First, an adequate amount (500 kBq) of 129I sample with a gold foil and some monitors is irradiated with fast neutrons in the YAYOI reactor to generate 130m, 130gI. The produced 130m, 130gI decays with half-lives of 9 minutes and 12.36 hours [15,27] while emitting 418, 536, 668, 739, and 1,157-keV decay gamma-rays, and then becomes stable 130Xe nuclide. In this sense, it can be said that 129I with a long half-life of 1.57 × 107 years was transmuted to the stable nuclide 130Xe through the neutron capture reaction. Next, the decay gamma-rays are measured with high-purity germanium (Ge) detector, and gamma-ray spectral data are analyzed. The reaction rates of 129I are then obtained from the net peak areas of the decay gamma-rays. Finally, a fast-neutron flux spectrum at an irradiation position is normalized using the reaction rate of the gold foil. The experimental reaction rate of 129I is compared with calculated reaction rates given by using the normalized neutron flux and the evaluated nuclear data libraries.
Review of Progress in Coated Fuel Particle Performance Analysis
Published in Nuclear Science and Engineering, 2020
Nairi Baghdasaryan, Tomasz Kozlowski
Recent studies and experiments for operating and accidental conditions show that there are a limited number of fission gases and metals that are relevant for FP behavior analysis.43 In particular, the number of relevant fission gases and metals mainly depends on the modeling conditions (operating history, short-lived or stable nuclide, heatup rate, etc.). All the above-mentioned diffusion models use a diffusion coefficient44 for predicting FP and metal release from the TRISO particle. However, there is a lack of experimental data for several fission gases and metals; therefore, additional research is needed to obtain a clear picture of this phenomenon.