[en] A radiochemical method permitting a rapid and efficient isolation of ²²⁸Ac isotope from ²²⁸Ra with a high degree of purity has been suggested. The method is based on Ac coprecipitation with rare earth compounds, gadolinium, in particular. The coprecipitation of the latter in the form of hydroxides is carried out from nitrate solutions by the action of ammonia. 2 refs

[en] The 14 radiochemical conference took place in Marianske Lazne (Czech Republic) in 14-19 April, 2002. Reports on problems of radioecology, radionuclides in environment, chemistry of actinides and transactinides, ionizing radiation in science and technology, chemistry of nuclear fuels and radioactive wastes, nuclear fuel reprocessing were presented

[en] The stabilization forms of ^119m,gTe atoms formed in metallic Sn by the nuclear reaction ¹¹⁷Sn(⁴He, 2n) were studied using Moessbauer spectroscopy. It was found that the stabilization forms of ^119m,gTe are determined by nuclear history (in this case, by the beam currents of bombarding particles) and, as a consequence, by the heat release in the target bulk

[en] The process of americium(6) reduction in the 4 mole/l NaOH solution at the 0 deg C temperature under azone influence is studied. The O₃ high concentration creates the O₃^- high content, the decomposition whereof is subjected to the law of the first-order rate. The O₃^- decomposition in accordance with the first-order reaction leads to origination of O₂^-, slightly reacting with Am⁶⁺. The O₃^- decomposition results in H₂O^-which reacts more slowly with O₃, therefore part of H₂O reduces Am⁶⁺. 7 refs

[en] Yields in radioactive chain of ²³⁸U of the following γ-quanta (keV): 63.3 (4.2%), 185.7 (48%), 766 (0.39%), 1001 (1.12%) were determined by the method of semiconductor γ-spectrometry of metal uranium foil. The yields of γ-quanta with 766.6 and 1001 keV energies proved 1.9 times higher than generally accepted ones

[en] Physicochemical properties of Ba¹⁴CO₃ obtained both through carbonization of barium-containing solutions and through the drop precipitation method, are studied. Analysis of quantitative characteristics (sedimentation velocity, final volume of residues bottoms, filtration coefficient) showed that for obtaining of barium carbonate with good sedimentation and filtration characteristics it is better to pass through carbon-14 dioxide through the solution of barium hydroxide or its mixture with barium nitrate (not more than 50 mass %), heated up to 60-70 deg C. In case of absorption of carbon dioxide by alkali solution the subsequent Ba¹⁴CO₃ precipitation showed be better conducted by adding in portions the solution of barium hydroxide, chloride or nitrate to the sodium (potassium) solution, heated up to 60-80 deg C. Optimal content of alkali in the carbonate solution equals 50-70 mass %

[en] Behaviour of Np(6) and (5) in ammonium and alkaline solutions in the range of pH 9.3 up to 8 mol/l NaOH during Fe(3) hydroxide precipitation forming as a result of FeO₄^2- reduction by hydrazine or nitroprusside hydrolysis is studied by radiometric method. It is shown that neptunium is coprecipitated with low purification factor. Such behaviour of neptunium deals with formation of anion complexes of Np(5) and these complexes are not contained in the structure of Fe(3) hydroxide and are not adsorbed by precipitate

[en] Uranium state in tributylphosphate (TBP) organic solutions in decane in a case of not high saturation as well as in maximally possible saturation is investigated. Using analysis of electron spectra of uranyl nitrate in TBP solutions in addition to disolvate presence of two extra forms of uranyl nitrate with TBP is detected. Form 1 is identified as cationic one - (TBP)_m-[UO₂(H₂O)_n(NO₃)]⁺, form 2 - as uranyl trinitrate complex [UO₂(NO₃)₃]^-. It is shown that with TBP concentration increase decrease of disolvate part and increase of content of forms 1 and 2 are observed. Increase of form 1 content is described by linear dependence on TBP concentration and in the case of form 2 - by square-law one. With temperature increase in TBP maximally saturated by uranyl nitrate transfer of disolvate in trinitrate complex with possible formation of ionic pair (TBP)_m-[UO₂(H₂O)_n(NO₃)]⁺[UO₂(NO₃)₃]^- takes place

[en] Hydroxamic acids soluble simultaneously in water as well as in organic solvents form with Mo stable extractable complexes. So Mo is not extracted by 30 % TBP but in the case of addition of benzohydroxamic acis C₆H₅CONHOH (BHA) (3 g/l BHA, 3 mol/l HNO₃) distribution coefficient of Mo increases up to ∼150 in the case of BHA:Mo=2. Further increase of the ratio leads to Mo distribution coefficient decrease. Complexes of BHA with Pd in the presence of BHA are extracted by 30 % TBP also while Mo distribution coefficient is in order higher. Presence of BHA increases extraction of Zr, Fe, Ru by 30 % TBP noticeably and in the same time not affects on extraction of rare earths, transplutonium elements and elements with low valence. With HNO₃ concentration increase extraction of Mo and other elements decreases. Hydroxamic acids of BHA type can be used for selective separation of Mo and Pd from high-level radioactive wastes. For these aims purified technical mixture of hydroxamic acids IM-50 in 30 % TBP can be used

[en] Meeting between Lawrence Livermore National Laboratory and Russian organization on consideration of problems of immobilization of excess quantities of armament plutonium in Russia took place in St Petersburg in 1999. Reports were joined into two block: plutonium immobilization and technology and industrial immobilization. All the reports were joined by general idea of nonproliferation of fissile materials, safety of radioactive wastes and solution of radioecological problems in Russia and in the world as a whole