Ion exchange /Extraction/Thorium/Protactinium / Uranium
SummaryIon exchange and extraction of Th, Pa, U and long-lived fission products (such as Zr and Nb) were studied with respect to the isolation of 231 Pa and of 2 32 U. Data showing the influence of HCl, HNO3 and H 2 S0 4 concentrations, F" concentration and Aid, concentration on the distribution coefficients are presented for ion exchange (mainly anion exchange) and extraction by TBP, DIBK, MIBK and amines. On the basis of the experimental results procedures were developed for separation of Th, Pa, U and fission products after neutron irradiation of 2 30 Th + 232 Th and of 231 Pa with the aim to isolate 2 31 Pa and 2 3 2 U in pure form quantitatively.
Actinides, detection of trace amounts /Laser resonance ionization mass spectrometry /Isotope analysis of plutonium
AbstractLaser resonance ionization mass spectrometry has been investigated as a method for the detection of trace amounts of actinides. High sensitivity and selectivity can be achieved by three-step photoionization followed by time-of-flight mass analysis. The laser system for photoionization consists of three dye lasers which are pumped simultaneously by a copper vapor laser. For mass determination a time-of-flight spectrometer with a mass resolution of about 1500 is used. By ionization via autoionizing states an overall efficiency of 4 X 10"' was determined for 23 ®Pu yielding a detection limit of less than 10 7 atoms. Isotope ratio measurements have been performed with synthetic plutonium samples.
Thoriumdioxide/Dissolution of ThO, ¡ThoriumResults and discussion
SummaryThe dissolution of ThO, which was heated to 750 and 1000°C (grain size 0.1 -0.2 mm) in mixtures of conc. HCl and various amounts of NH 4 F was investigated. The dissolution depends strongly on the mole ratio NH,F/Th0 2 . A minimum value of this ratio is necessary for the total dissolution of ThO,.
230 Th (ionium) is of interest for production of 23 'Pa, the Pa isotope with the longest half life, and for production of 232 U which can be used in radionuclide batteries. Two procedures are presented which have been worked out for separation of 23^T h from sulfuric acid and from nitric acid solutions. In the first case the effluents from the anion exchange resins are the starting material for recovery of 230 Th, in the second case the cation exchange resins which are used for purification of U. The procedures selected are simple, economic and can be performed in any uranium mill or uranium purification plant without additional investments.
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