[en] By means of electrophoretic focussing relatively large amounts can be separated into groups. It is shown that an even better separation can be achieved in a two-dimensional method. The first step of a normal zone electrophoresis is followed by electrophoretic focussing. A sample containing about 0.3 mg metal-ions was separated within 20 minutes. A further advantage over other two-dimensional methods is that the ions are concentrated into small zones by the second step. (author)

[en] A two-steps chemical treatment technique for strontium assessment from aqueous samples is described in this paper. The method was applied to simulated samples containing stable elements of Ni, Cs, Ca, Ba, Mn, Fe, Co and Eu. The transition elements (Ni, Mn, Fe, Co, Eu) were precipitated as hydroxides, followed by alkaline-earth metals separation (Ca, Ba) as carbonates. Finally, the Sr was purified by extraction chromatography using Triskem International Sr resin. The strength of Sr sorption in nitric acid increases with increasing acid concentration, and the optimal bonding strength is achieved in 8 M HNO3. The combination of successive precipitations with extraction chromatography for complete removal of other interferences from Sr matrix leads to good recovery and decontamination factor values. (authors)

[en] A quantitative gravimetric determination of samarium in presence of various diverse ions and rare earths as Ce³⁺, La⁺³, Pr⁺³, Nd⁺³, Th⁺⁴, Zr⁺⁴, V⁺⁵, Mo⁺⁶ and U⁺⁶ can be made by precipitation with N-m-tolyl-m-nitrobenzohydroxamic acid. A solution containing 6.76 mg of samarium nitrate was precipitated at pH 9.6-10.2. The complex having the composition (C₁₄H₁₁N₂O₄)₃Sm was weighed directly after drying at 110 deg. It was possible to separate Sm from Pr and Nd

[en] This study on the enhancement of Tc extraction and the selective separation of Tc, Np and residual U by means of adding a small amount of tri-n-octylamine(TOA) in the 30% vol. tributyl phosphate(TBP)/n-dodecane was performed. Co-extraction of Tc, Np and U from the 10 components simulated radwaste solution containing the 0.005M-K₂Cr₂O₇ as an oxidant of Np by 30% TBP/0.5% TOA, and selective stripping of Tc, Np and U from the loaded organic phase were investigated, and their operation conditions were evaluated. Tc, Np and U was effectively co-extracted at O/A=1 and 1M HNO₃. In this condition, the co-extraction yields of Tc, Np and U were 81.9%, 86%, 89.2%, respectively and those of Am, Eu, Nd, Mo and Fe were below 5%. For the selective stripping of extracted Tc, Np and U, however, sequentially 5M HNO₃ and O/A=1 for Tc, reduction of Np(VI) to Np(V) with 0.175M n-butyraldehyde (NBA) and O/A=2 for Np, and 0.15M Na₂CO₃ and O/A=1 for U were used, respectively. In this case, 79% of Tc(co-stripping of less than 4% Np and U), 84% of Np(co-stripping of about 6% U), above 99% of U could be recovered, respectively

[en] Separation of actinides from spent nuclear fuel is a part of the process of recycling fissile material. Extracting agents for partitioning the high level liquid waste (HLLW) from conventional PUREX reprocessing is studied. The CTH-process is based on three consecutive extraction cycles. In the first cycle protactinium, uranium, neptunium and plutonium are removed by extraction with di-2-ethylhexyl-phosphoric acid (HDEHP) from a 6 M nitric acid HLLW solution. Distribution ratios for actinides, fission products and corrosion products between HLLW and 1 M HDEHP in an aliphatic diluent have been investigated. To avoid addition of chemicals the acidity is reduced by a tributylphosphate (TBP) extraction cycle. The distribution ratios of elements present in HLLW have been measured between 50 % TBP in an aliphatic diluent and synthetic HLLW in range 0.1-6 M nitric acid. In the third extraction cycle americium and curium are extracted. To separate trivalent actinides from lanthanides a method based on selective stripping of the actinides from 1 M HDEHP is proposed. The aqueous phase containing ammonia, diethylenetriaminepentaacetic acid (DTPA) and lactic acid is recycled in a closed loop after reextraction of the actinides into a second organic phase also containing 1 M HDEHP. Distribution ratios for americium and neodymium have been measured at varying DTPA and lactic acid concentrations and at varying pH. Nitrogen-donor reagents have been shown to have a potential to separate trivalent actinides from lanthanides. 2,2':6,2''-terpyridine as extractant follows the CHON-principle and can in synergy with 2-bromodecanoic acid separate americium from europium. Distribution ratios for americium and europium, in the range of 0.02-0.12 M nitric acid, between nitric acid and 0.02 M terpyridine with 1 M 2-bromodecanoic acid in tert-butylbenzene (TBB) was investigated. Comparison with other nitrogen-donor reagents show that increasing lipophilicity of the molecule, by substitution of alkyl chains to the structure or by changing the position of the nitrogens in the molecule, can be a way to get higher distribution ratios and higher separation factors

[en] A crude Craig-distribution in the system 11M HNO₃-TBP (input up to 200 g oxide) proved to be a rapid method to get highly enriched mixtures of yttrium earths completely free from cerium earths, which can be further separated economically, e.g. by Crraig-distribution. (author)

[en] Problem related to the choice of optimum criterion in tasks of approximation of Q-cascades, used for separating the multi-component isotope mixtures, by cascades with the square-sectioned profile is discussed. The proposed approach may be used when calculating optimal cascades having several supply and extraction flows

[en] Mixed fission and activation materials resulting from various nuclear processes and events contain a wide range of isotopes for analysis spanning almost the entire periodic table. This work describes the production of a complex synthetic sample containing fission products, activation products, and irradiated soil, and determines the percent chemical recovery of select isotopes through the integrated chemical separation scheme. Based on the results of this experiment, a complex synthetic sample can be prepared with low atom/fission ratios and isotopes of interest accurately and precisely measured following an integrated chemical separation method. (author)

[en] A method is presented for calculating diffusion transport in centrifuges, taking into account the concentration dependence of the generalized diffusion coefficients. Some results illustrating the effect of the mixture concentration on the separation characteristics of a centrifuge are also presented. Investigations showed that, for the examples considered, a diagonal matrix representation can give good results for calculating the generalized diffusion coefficients. The formulas give more accurate results, but are less convenient for calculations. 11 refs., 1 fig., 1 tab

[en] The nuclei collecting is concerned essentially with isotope production and identification, and then with the use of the such radioactivities to studying reaction mechanisms. The basic characteristics of the various methods used are: the collection time, the possibility of identifying the radioactivity produced and of measurements of the specific characteristics of the nuclear reaction studied (energy, angular distribution). The performance of the principal techniques now in use are reviewed