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Determination of Metals in Soils
Published in T. R. Crompton, Determination of Metals and Anions in Soils, Sediments and Sludges, 2020
Dienstbach and Bachmann [125] have determined plutonium in amounts down to 20 fCiPug−1 soil in sandy soils by an automated method based on gas chromatographic separation and α spectrometry. In Fig. 2.20 is shown an α spectrum of vapour deposited plutonium chloride containing 3.6 pCi 242Pu, 0.18 pCi 239Pu and 0.43 pCi 238Pu. In this procedure, the sample is decomposed completely by hydrogen fluoride. The hydrogen fluoride is evaporated and the residue is chlorinated. Plutonium is separated from the sample by volatilization and separation of the chlorides in the gas phase. The plutonium is deposited on a glass disk by condensation of volatilised plutonium chloride. The concentration of plutonium is then determined by a spectroscopy.
Pyrochemical Treatment of Salts
Published in Thomas E. Carleson, Nathan A. Chipman, Chien M. Wai, Separation Techniques in Nuclear Waste Management, 2017
In MSE, plutonium metal is contacted with a molten-salt mixture containing an americium oxidant such as magnesium chloride (MgCl2), or more recently plutonium chloride (PuCl3) added as either PuCl3 or dicesium hexachloroplutonate (Cs2PuCl6). The Cs2PuCl6 decomposes to PuCl3 and cesium chloride (CsCl) as the temperature of the process is increased. The MgCl2 or PuCl3 selectively oxidizes Am0 to a chloride that is extracted into the molten-salt phase. Some of the plutonium metal feed is also entrapped in the salt phase as metal shot or flakes. This plutonium metal and that in unreacted PuCl3, as well as the extracted americium, must be recovered before the salt residue can be discarded or recycled.
The Taming of Plutonium: Plutonium Metallurgy and the Manhattan Project
Published in Nuclear Technology, 2021
Joseph C. Martz, Franz J. Freibert, David L. Clark
Even before plutonium had become available, metallurgists at Los Alamos and Chicago’s Met Lab realized they would need to develop chemical techniques to prepare plutonium compounds that would be suitable for reduction into pure metal.1,7,24,25 The metallurgists had been working with an exothermic reaction known as metallothermic reduction, in which a plutonium chloride or fluoride compound (PuCl3, PuF4, etc.) is reduced at high temperature in a molten salt containing an active metal like calcium, all sealed inside a metal container referred to as a bomb.1,24
A New Era of Nuclear Criticality Experiments: The First 10 Years of Planet Operations at NCERC
Published in Nuclear Science and Engineering, 2021
Rene Sanchez, Theresa Cutler, Joetta Goda, Travis Grove, David Hayes, Jesson Hutchinson, George McKenzie, Alexander McSpaden, William Myers, Roberto Rico, Jessie Walker, Robert Weldon
Future work includes measurements of the prompt fission neutron spectrum using threshold activation foils and other detectors, additional TEX-Pu experiments with thicker moderators to support TSL evaluations, follow-on experiments to Hypatia with additional materials, and experiments to provide criticality safety analysts at the Y-12 National Security Complex and LANL with validation cases for operations involving chlorine in electrorefining and aqueous plutonium chloride processing.
DFT study on the bonding properties of Pu(III) and Pu(IV) chloro complexes
Published in Journal of Nuclear Science and Technology, 2018
Keunhong Jeong, Seung Min Woo, Sungchul Bae
Because of the lack of information about the target compound, we assessed the quality of the level of theory which was implemented. Recently, the average Am–Cl bond distance in Americium(III) hexachloride (AmCl63−) was measured to be 2.724 Å [20]. Quantum calculations on AmCl63− were performed by using the same level of theory. The average bond distance was found to be 2.809 Å, which is a slight overestimation of the experimental data (structure and coordinates are presented in SI). It is evident that the calculated structures are optimized in the gas phase and ignore the polarization effects of the crystal structure. With the same level of theory, the optimized structures of Pu(III)Clx(x, 2-8) and Pu(IV)Clx(x, 2-8) are illustrated in Figure 1. All structures were considered to be nearly the same geometry as presented in the previous study (coordinates are presented in SI) [2]. There were no significant symmetrical or geometrical differences between the Pu(III) and Pu(IV) structures (Figure 1). The average plutonium–chloride distance in each compound versus the number of coordinated chlorides is plotted in Figure 2. The overall trend shows a gradual increase in distance between plutonium and chloride with increasing coordination number. Steric forces and electronic interactions between chlorides contribute to the increasing bond length. Also, the smaller bond lengths of the Pu(IV) species can be explained by larger electrostatic interactions compared with Pu(III) structures. NPA charges were calculated to understand more about the bonding properties of the plutonium complexes (Figure 3). Interestingly, there is a significant change after n = 6 in each structure which differs from the previous report [13]. In the case of PuCl6(III) and PuCl6(IV), the NPA of plutonium is 0.78 and 0.25, respectively, whereas the NPA of PuCl2(III) and PuCl2(IV) is 1.92 and 2.19, respectively. This implies that the bonding properties between plutonium and chloride might be very different because their structures were almost the same as each other.