O. D. Maslov

Preparation of 99Mo and 99mTc by 100Mo(γ,n) photonuclear reaction on an electron accelerator, MT-25 microtron

Molybdenum-99 was prepared by 100Mo(γ,n) photonuclear reaction on an electron accelerator, MT-25 microtron (FLNR). Natural Mo foil (9.6% 100Mo) and 100MoO3 (100% 100Mo) were used as the targets. The radiation yield of 99Mo was 3.2 kBq/(μA h mg 100Mo). Technetium-99m was isolated from the target material and concomitant radioactive impurities by an ion-exchange procedure. The possibility of preparing 99mTc generator from molybdenum carbonyl was studied. The content of radioactive impurities in the final 99mTc preparations was no higher than 10−5 Bq Bq−1.

Uranium recovery from coal ash dumps of Mongolia

The concentration of natural radionuclides and the feasibility of recovery of uranium from browncoal ash of a Mongolian cogeneration plant were investigated. The concentrations of the elements were determined by instrumental gamma-activation (IGAA) and X-ray fluorescence (XRF) analysis. Uranium from brown-coal ash was leached with an 8 M HNO3 + HF (10%) mixture. The extraction of uranium from the solution and its purification for the removal of accompanying elements were carried out on an anion exchanger. An ash sample after leaching contains neither natural radioactive elements (238U and 232Th) nor their decay products, thereby allowing for the use of the ash as a building material.

Preparation of 225Ac by 226Ra(γ, n) photonuclear reaction on an electron accelerator, MT-25 microtron

Abstract237U was prepared by 238U(γ,n) reaction on an electron accelerator (MT-25 microtron) at FLNR. The radiation yield of 237U was 1 Bq/(μA h mg 238U). 237U was recovered from the target by collection of recoil nuclei in the solid:solid system. Group I–III element fluorides were used as the 237U acceptor. 237U was separated from the fission products by extraction and ion-exchange procedures. The specific activity of 237U in the sample was 49 500 kBq/mg 238U. The content of radioactive impurities in the preparation was no higher than 10−5. The chemical yield of 237U was 70%.

Use of a nanostructured material for separation of 238U and 237U produced by the photonuclear reaction 238U(γ, n)237U

Abstract237U was produced by the reaction 238U(γ, n) on an electron accelerator, MT-25 microtron, at the Flerov Laboratory of Nuclear Reactions. For the separation of 237U and [238U, the recoil nuclei were collected by a nanostructured material, hydrated manganese dioxide (of the cryptomelane type), in the solid-solid system. From fission products, 237U was separated by ion exchange. The specific activity of the resulting 237U was 4.5 × 109 Bq (mg 238U)-1, with the content of radioactive impurities of ≤10-6 Bq Bq-1. The chemical yield of 237U was 80%.

Sorption of U(VI) with soil from the region of location of the Novi Khan radioactive waste repository in Bulgaria

Sorption of U(VI) with soil from the region of location of the radioactive waste repository was studied. The radionuclide 237U produced by the photonuclear reaction 238U(γ, n)237U on an electron accelerator, MT-25 microtron (FLNR, JINR), was used as tracer. The U(VI) speciation in solution at various U concentrations was calculated in the range pH 1–7 using the Speciation program.

Behavior of zirconium and hafnium ions in ultramicroconcentrations investigated by horizontal zone electrophoresis in free electrolyte

The electrophoresis of zirconium and hafnium ions in aqueous solutions was investigated. No-carrier-added 88Zr and 175Hf have been used in microconcentrations (10-11M). The complexation of zirconium and hafnium with DTPA has been investigated in a large pH interval. The stability constants of the Zr-DTPA and Hf-DTPA complexes were determined for the first time by the method of horizontal zone electrophoresis in free electrolyte. The electrophoretic behavior of Zr(IV) and Hf(IV) ions in nitric acid solutions has also been studied.

Low level measurements of thorium and neptunium in environmental samples using the (γ, f) reaction

A new highly sensitive track method for the determination of thorium (232Th) and neptunium (237Np) has been developed. The technique includes the radiochemical separation procedure of the isotopes followed by the irradiation of the resultant samples on the MT-25 microtron. The detection limit is équivalent up to 3·10−13 g of232Th and 7·10−14 of237Np. The method was used to determine232Th and237Np isotopes in water samples.

Cation-exchange chromatographic separation of mendelevium and fermium using α-hydroxy-α-methylbutyrate

A good separation of the pair Md-Fm was performed on a spheroidal cation exchanger OSTION by means of ammonium α-hydroxy-α-methylbutyrate. The sepation factors and the position of elution peaks for elements of pairs Md-Fm and Ho-Dy are similar.

Determination of Diffusion Coefficients of In, Cd, Hf and Pu Hydrated Ions in Aqueous Solutions Using the Method of Horizontal Zone Electrophoresis in Free Electrolyte

The method of determination of ion diffusion coefficients in aqueous solutions using the horizontal zone electrophoresis device in the free electrolyte is described. The difiusion coefficients of Cd (II), In (III), Zr (IV), Hf (IV) and Pu (VI) in nitric acid solutions are determined.