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.
Authors:N. Shinohara, N. Kohno, T. Suzuki, and S. Usuda
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.
Authors:S. Usuda, N. Shinohara, H. Yoshikawa, S. Ichikawa, and T. Suzuki
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.
Authors:Y. Hatsukawa, M. Oshima, T. Hayakawa, Y. Toh, and N. Shinohara
Feasibility of the method of multidimensional -ray spectrometer for neutron activation analysis was examined. Reference igneous rock (JP-1, JB-1a and JB-1) samples issued by the Geological Survey of Japan (GSJ) and the Allende meteorite reference sample were irradiated in a research reactor, and multiple -rays from the produced radioisotopes via neutron capture reactions were measured using an array of twelve germanium detectors with BGO Compton suppressors called GEMINI. Simultaneously thirty elements were observed with no chemical separation. The observed smallest component was Eu contained in JP-1 with abundance of 4 ppb.
Authors:Y. Toh, M. Oshima, Y. Hatsukawa, T. Hayakawa, and N. Shinohara
A comparison method, utilizing neutron activation analysis followed by multidimensional spectrum analysis was proven to provide accurate quantification of the multi-element samples. In this study, 23 elements were detected simultaneously in a sample containing standard elements for neutron activation analysis. The method presented here can be applied for about 50 elements.
Authors:Y. Hatsukawa, Y. Toh, M. Oshima, T. Hayakawa, N. Shinohara, K. Kushita, T. Ueno, and K. Toyoda
Multiparameter coincidence g-ray spectrometry based on g-g coincidence is widely used in the field of nuclear structure studies, and has produced many succesful results. In this paper, feasibility of the method for neutron activation analysis of trace elements was studied. Particularly, a long-lived radioisotope 129I (T1/2 = 1.57.107 y) in algae samples and iridium in geological samples has been determined.
Authors:N. Shinohara, Y. Hatsukawa, K. Hata, N. Kohno, M. Andoh, H. Saleh, W. Charlton, T. Parish, and S. Raman
For nuclear transmutation of minor actinides, delayed neutron emission measurement for241Am was carried out in thermal neutron irradiation location. The neutron capture cross sections of241Am were also measured radiochemically. The transmutation process of241Am in reactor is discussed by calculating the yields of minor actinides with the nuclear data measured in this study and the
evaluated values. The accelerator driven transmutation of minor actinides by high-flux neutrons from spallation reactions
is also presented.
Authors:Y. Hatsukawa, N. Shinohara, K. Hata, K. Kobayashi, S. Motoishi, M. Tanase, T. Katoh, S. Nakamura, and H. Harada
To determine the cross sections of the135Cs(n,γ)136Cs reaction, a sample of135Cs included in a “standardized solution” of137Cs was used as a target and irradiated in a reactor. The ratio of the atom number of135Cs to that of137Cs was determined to be 0.89±0.03 with a quadrupole mass spectrometer. The thermal cross section and the resonance integral
measured in this study were determined to be 8.3±0.3 and 38.1±2.6 b respectively.