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Yamada, Kunimi; Hanamuro, Takahiro; Tagami, Takahiro*; Yamada, Ryuji*; Umeda, Koji
no journal, ,
Japan Atomic Energy Agency have jointly set up the system of the (U-Th)/He dating in cooperation with Kyoto University and National Institute for Earth Sciences and Disaster Prevention. Through this two years, helium extraction machine using an electronically-cooled diode laser, micro crusible system using XRF bead sampler and uranium and thorium quantification procedure without artificial spikes are developed. Now we produce new ages of some age known samples. At the present stage, the accuracy and precision are roughly 20 and 10%, respectively, using the age standard zircon from the Fish Canyon Tuff (FC3). In the presentation, we will introduce our systems and the ages detailedly.
Kozai, Naofumi; Onuki, Toshihiko
no journal, ,
The impact of activity of microorganism such as bacteria and yeast on the radionuclide migration leached from radioactive wastes has been investigated intensively. However, the role of protozoa, who pray bacteria and yeast, in the migration of radionuclides is not clarified at all. This study selected Paramecium bursaria as representative of protozoa and yeast as representative of food microorganism and investigated the behavior of Eu(III) during culture of paramecium with addition of yeast sorbing Eu(III). The Eu(III) on yeast was hardly solubilized in culture media during the culture of paramecium. Most of Eu(III) was found in undigested residue of yeast and extracellular polymeric substance of paramecium.
Onuki, Toshihiko; Kozai, Naofumi; Sakamoto, Fuminori; Ozaki, Takuo; Nankawa, Takuya; Suzuki, Yoshinori; Francis, A. J.*
no journal, ,
We summarize our findings on the interactions of actinides with microorganism and organic ligands. Malic acid formed complexes with Eu(III), analogues of Am(III) and Cm(III), but degradation of malic acid by Pseudomonas fluorescens was observed. One of the metabolites associated with Eu(III), that were produced by the degradation of malic acid, was determined as pyruvic acid by ESI-MS. These findings strongly suggest that interaction of microorganisms with the of actinide organic complexes affect the migration of actinides.