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  • Author or Editor: S. Usuda x
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Abstract  

Anion exchange behaviour of the transplutonium (Am, Cm and Cf), rare earth (Y, Ce, Pm and Eu) and some other elements (U, Al, Sr and Cs) has been investigated in nitric acid-methyl alcohol media at temperatures up to 90°C. Distribution coefficients and separation factors of the elements were determined in the media at 90°C as a function of concentrations of nitric acid and methyl alcohol. Separation factors decrease significantly but the resolution of eluted elements improves with increasing temperature. Chromatographic separation of those elements was rapidly performed by using a very small column at 90°C. The effluent of the column received on a metal disk can be readily evaporated and one may immediately prepare samples for alpha-ray spectrometry.

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Abstract  

The anion exchange behaviour of transplutonium elements, Am, Cm and Cf, has been studied in 0.3–1.3M hydrochloric acid solutions containing methyl alcohol 85% or more at elevated temperature. The distribution coefficients of the elements were increased monotonically with increasing concentration of hydrochloric acid and/or that of methyl alcohol at 90°C by forming anionic chloride complexes. Californium was separated by anion exchange within several drops of effluent from the trace amounts of americium, curium and fission products and macro amounts of aluminium and uranium, and samples for alpha-ray spectrometry were immediately prepared by directly evaporating the eluent drops on a counting disk.

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Abstract  

Anion exchange chromatography with nitric acid-methyl alcohol mixed media at elevated temperature has been applied to mutual separation of the light lanthanoids, La, Ce, Pr, Nd and Pm. The individual elements could be effectively separated from each other, main fission products and actinoids with 0.01M HNO3-90% CH3OH or 0.5M HNO3-80% CH3OH eluent at 90 °C.

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Abstract  

Volume distribution coefficients /Dv/ were determined for the adsorption of U and several other elements on anion-exchange resin from mixed solutions of tetrafluoroboric acid and nitric acid or hydrochloric acid, and the effect of tetrafluoroboric acid on the adsorption of each element was studied. The addition of tetrafluoroboric acid, in general, slightly decreased the Dv values while Zr was weakly adsorbed in the HBF4–HCl and HBF4–HNO3 solutions and Nb in the HBF4–HNO3 solutions.

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Abstract  

A simple pressurized ion exchange apparatus has been devised for rapid ion exchange separation of transplutonium elements synthesized by heavy ion bombardment. Cation exchange with mixed media of mineral acids and organic solvents at elevated temperature was used to separate the transplutonium elements from uranium targets and/or catcher foils (aluminium and copper) dissolved in aqua regia. The transplutonium elements were strongly adsorbed on the cation exchange column and separated in a group from rare earths by elution with hydrochloric acid or mutually separated with 2-hydroxy-2-methylpropionate solution. It has been successfully applied to separate and identify250Fm and246Cf synthesized by the16O+238U reaction.

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Abstract  

In order to examine the feasibility of the adsorbed compounds on the pine needles for environmental monitoring of uranium, the adsorbed compounds were recovered by solvent washing, and the elemental concentrations in the compounds were compared with those of air particles and pine needles. It was found, that the concentration patterns of elements in the compounds corresponded to those of air particles, which meant that the air particles were the main components of the compounds. The analysis by ICP-MS suggested that the uranium in the compounds has a natural composition. Therefore, the adsorbed compounds to the pine needles can be considered as potential indicators for the environmental monitoring of uranium.

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Abstract  

Anion exchange separation of250Fm (30 m) synthesized by the12C+242Pu and16O+238U reactions has been investigated with mineral acid-methyl alcohol mixed media at elevated temperature. Fermium was chromatographically separated from the other transplutonium elements, the target materials and an Al catcher foil by anion exchange with mixtures of nitric acid and methyl alcohol. By use of the mixed media of hydrochloric acid and methyl alcohol, Fm together with Cf was separated from Al, Am, Cm, Pu, U and major fission products. The separation systems are suitable for rapid separation and immediate alpha-counting source preparation of Fm.

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Abstract  

In order to assess the extent of the elimination of humidity and the presence of pine trees on the elemental composition of airborne dust, the concentration of 21 elements were measured in airborne dust collected with a high-volume sampler at JAERI by instrumental neutron activation analysis (INAA). It was found that the concentration of soil-origin elements, such as Al, Sc and Th, decreased as the humidity increased, and the Cl/Na ratio of sea salt constituent in the dust samples increased with the decrease of humidity after the felling of the trees.

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Abstract  

A method for analyzing the content of237Np in spent fuel has been developed using inherent239Np as a chemical yield monitor. After ion-exchange separations for the dissolved fuel solution, the237Np content in the neptunium fraction was determined from the activity of237Np or of233Pa, which is in radioactive equilibrium with237Np. The chemical yield in the separations was determined both from the content of243Am which is in radioactive equilibrium with239Np before the separations and from the239Np content in the neptunium fraction after the separations by alpha- and gamma-ray spectrometry.

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Abstract  

To clarify the magnitude of wash-out effect of rain on the elemental composition of airborne dust and the possible origin of the dust, the dust samples were collected with a high-volume air sampler at the JAERI-Tokai. The dust suspended in rain was also collected from rain by filtration. Up to 20 elements in both types of the dust were determined by instrumental neutron activation analysis. It was found that the elements determined could be classified into 3 groups from the elemental composition and the elemental correlation in both types of the dust samples.

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