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Reactor Heat Transfer
Published in G. Vaidyanathan, Dynamic Simulation of Sodium Cooled Fast Reactors, 2023
Boron in the form of boron carbide (B4C) is used as absorber rod material for controlling the power of the nuclear reactors. Natural boron contains 20% B10, and the rest is the B11 isotope. B10 is the isotope with neutron absorption properties. While water reactors use natural boron, fast reactors use boron enriched in B10 to ~60–70%. Boron swells on absorption of a neutron due to the production of helium. This necessitates replacement of control rods once in ~2 years. Tantalum is being considered as a possible substitute, primarily because of its favorable swelling characteristics and availability. The disadvantage is the 115-day half-life gamma decay from Ta182 to W182, which causes long-term decay heat removal problems. Also, Ta is soluble in sodium. Europium oxide is another candidate. It has twice the neutron absorption capability compared to boron. However, it has many disadvantages from reactivity and low thermal conductivity considerations. In light of this, boron is continued to be used as an absorber material in control rods.
2+doped strontium phosphate blue phosphor by Sol-gel method
Published in Domenico Lombardo, Ke Wang, Advances in Materials Science and Engineering, 2021
L.Q. Wu, Y. Wang, S.Y. Guan, J.R. Li
The main materials used in this experiment include europium oxide, strontium carbonate, diammonium hydrogen phosphate, concentrated nitric acid, methanol, acetic acid and so on. Strontium phosphate phosphors doped with europium were prepared by sol-gel method with strontium carbonate, diammonium phosphate and europium oxide as main raw materials. According to the experiment, Sr2P2O7:Eu2+ stoicheometric ratio was determined, the raw materials were accurately weighed, various solutions were mixed in the beaker until they were clarified, and then poured into a three-neck flask for water bath heating at 80°C. Under the action of an electric agitator, the gel was formed. The doping amounts of Eu3+ ions were 2.0%, 3.5%, 6.0%, 8.0% and 10.0%, respectively. After gelation, the mixture was dried, ground into powder and put into crucible. The mixture was calcined at 800°C~900°C in muff furnace, and the heat treatment time was 4~5 h. After cooling, the mixture was separated and ground to obtain nanometer blue phosphor.
Ionic Liquid as Green Solvents
Published in Satish A. Dake, Ravindra S. Shinde, Suresh C. Ameta, A. K. Haghi, Green Chemistry and Sustainable Technology, 2020
Avinash Kumar Rai, Seema Kothari, Rakshit Ameta, Suresh C. Ameta
Banda et al. [68] separated yttrium/europium oxide, into its individual elements which was obtained by the processing of fluorescent lamp waste powder using solvent extraction. They used two undiluted ILs, trihexyl(tetradecyl) phosphonium thiocyanate, [C101][SCN], and tricaprylmethylammonium thiocyanate, [A336][SCN] for this purpose. The best extraction performance was obtained with [C101][SCN] on using an organic-to-aqueous volume ratio of 1/10 and four counter-current extraction stages. A loaded organic phase was scrubbed with a solution of 3 mol L–1 CaCl2 + 0.8 mol L–1 NH4SCN for removing the co-extracted europium. Yttrium was then quantitatively stripped from the scrubbed organic phase using deionized water. Yttrium and europium were finally recovered as their corresponding hydroxides by precipitation with ammonia, followed by calcination to the respective oxides. They also tested yttrium/europium separation from synthetic chloride solutions on a leachate obtained from the dissolution of a real mixed oxide. The purity of Y2O3 with respect to the rare-earth content was found to be 98.2% while the purity of Eu2O3 with respect to calcium was 98.7%.
The electrocaloric effect in BaTiO3:Eu ceramics determined by an indirect method
Published in Phase Transitions, 2021
Przemysław Gwizd, Dorota Sitko, Irena Jankowska-Sumara, Magdalena Krupska-Klimczak
The ceramics of pure BaTiO3 and BaTiO3+2%Eu (BTE-2) were synthesized from an analytically pure barium carbonate BaCO3, titanium oxide TiO2, and europium oxide Eu2O3 (in the case of BTE ceramic). The ceramics were manufactured using the standard ceramic technology via a solid-state reaction. The details of the synthesis were described in [24]. The structure of the obtained ceramics was confirmed by XRD measurements and the electron state by the XPS technique and presented in [27]. For the current experiment, the ceramics samples were cut into thin plates with average dimensions of 3 × 1 × 0.5 mm3. The density of the samples was measured by the Archimedes method. For the ceramics, under investigations, the measurements of the specific heat were made as first. Those measurements were made using the commercial Netzsch DSC F3 Maia calorimeter. Then, for the dielectric and electrical measurements, the silver electrodes were pasted at room temperature on the opposite faces of the sample. The dielectric properties were measured with the use of an Agilent E4980A LCR meter. Using a conventional Sawyer-Tower setup, the D–E hysteresis loops were measured in a quasistatic limit. The frequency of the test signal was set up to 6 Hz and the amplitude of the electric field changed from 0 to 1.2*105 V/m. The measurements were made from room temperature up to about 20–30 K above the temperature of phase transition.
Functionalized Dipicolinic Acid Derivatives as TALSPEAK-MME Stripping Agents
Published in Solvent Extraction and Ion Exchange, 2021
Nicolas E. F. Uhnak, Kenneth L. Nash
The analysis of the stable (non-radioactive) metal ions was conducted using an ICP-MS Multielement standard-B from High Purity Standards. Samples containing all stable Ln, Y, Sc, and Th at 10 μg/mL were diluted to 1 ppm (0.13 mM total metal) to give final acid concentrations of 0.3 and 0.5 M HNO3 by serial dilution. Zirconium and molybdenum ICP standards at 1000 μg/mL from High Purity Standards were diluted to 1 ppm in 0.50 M HNO3 by serial dilution. Rh, Ru, and Pd were received from Aldrich as the hydrated chloride salts at greater than 99.9% purity. These salts were dissolved in 0.50 M HNO3 and diluted to 1 ppm in the same acid. The 241Am and 244Cm tracers in nitric acid were received from Pacific Northwest National Laboratory (Richland, WA). The 152/154Eu tracer was prepared in a 1-MW Teaching, Research, Isotopes, General Atomics (TRIGA) reactor at the Nuclear Science Center at WSU by irradiating europium oxide (99.999% pure from Arris) dissolved in nitric acid and standardized for activity.
Luminescent property of Y2O2S:Eu3+ nanophosphors prepared by molten salt synthesis
Published in Inorganic and Nano-Metal Chemistry, 2019
Xiuzhao Yin, Lingna Liu, Jihui Yang, Zifei Peng, Yuxiang Yang
Y2O2S:Eu3+ nanophosphors were synthesized through a simple molten salt method. In a typical process, yttrium salt of rare earth oxides (3 mmol), powdered sulfur (1.154 g), europium oxide (0.5%), and moderate molten salt were gradually added and grounded in the aluminum oxide crucible until it was even, then the mixture were deoxidized at 900 °C for 2 h, the reaction products were dissolved in absolute ethyl alcohol and magnetically stirred for 3 times. Then the solution was heated to 6 °C and maintained at this temperature for 6 h. The employed Eu2O3 was produced by the Aladdin Chemical Co., LTD, Shanghai, China, with the other reagents all produced by the Shanghai Runjie Chemical Co., LTD, Shanghai, China.