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Journal Articles

Sequential anion-exchange separation of trace U, Th, Pb and lanthanides in environmental samples

Miyamoto, Yutaka; Yasuda, Kenichiro; Magara, Masaaki; Kimura, Takaumi; Usuda, Shigekazu*

Proceedings in Radiochemistry, 1(1), p.209 - 212, 2011/09

Nano grams of U, Th, Pb and lanthanides in a geological reference rock were sequentially separated with a single anion-exchange column. Mixture of acetic acid, HCl and HNO$$_{3}$$ were used as the eluents for this separation. The recovery of these key elements was more than 95%, and there was no fractionation among the recoveries of each lanthanide element. Alkaline metals, alkaline earth metals and Fe were effectively eliminated from the key elements. By using this technique, it is possible to simplify the complicated traditional processes without any special ligands, columns and equipments.

Journal Articles

Radiochemical study of sub-barrier fusion hindrance in the $$^{19}$$F+$$^{209}$$Bi reaction

Nishinaka, Ichiro; Kasamatsu, Yoshitaka*; Tanikawa, Masashi*; Goto, Shinichi*; Asai, Masato

Proceedings in Radiochemistry, 1(1), p.117 - 121, 2011/09

Unexpected steep falloff of fusion cross sections has recently been observed in heavy-ion fusion reactions at deep sub-barrier energies. In this study the fusion-fission cross sections for $$^{19}$$F+$$^{209}$$Bi at sub-barrier energies were determined by a radiochemical method in order to study sub-barrier fusion hindrance. We will discuss the sub-barrier fusion hindrance in heavy-mass systems, comparing the theoretical calculations and the systematics.

Journal Articles

Absorption spectra and cyclic voltammograms of uranium species in molten lithium molybdate-sodium molybdate eutectic at 550 $$^{circ}$$C

Nagai, Takayuki; Uehara, Akihiro*; Fukushima, Mineo; Myochin, Munetaka; Fujii, Toshiyuki*; Sato, Nobuaki*; Yamana, Hajimu*

Proceedings in Radiochemistry, 1(1), p.151 - 155, 2011/09

Absorption spectra of dissolved uranium species in molten Li$$_{2}$$MoO$$_{4}$$-Na$$_{2}$$MoO$$_{4}$$ eutectic at 550 $$^{circ}$$C were measured by spectrophotometry, and their redox reactions were also investigated by cyclic voltammetry. Observed absorption spectra of uranium species were similar to those of UO$$_{2}$$$$^{+}$$ in molten chlorides. After purging oxygen into the melt, the absorption peaks of UO$$_{2}$$$$^{+}$$ decreased and UO$$_{2}$$$$^{+}$$ was thought to be oxidized to UO$$_{2}$$$$^{2+}$$. When the uranium species were not contained in the melt, we confirmed that alkali metals deposited at -0.7 V and a small reduction of this melt was observed at -0.3 V. When UO$$_{2}$$ was dissolved into the melt, the reduction of the uranium species was observed at -0.2 V. It was suggested that the dissolved uranium species are recovered as mixed uranium-molybdenum oxides by electrolysis.

Journal Articles

Study on cleaing solvents using activated alumina in PUREX process

Arai, Yoichi; Ogino, Hideki; Takeuchi, Masayuki; Kase, Takeshi; Nakajima, Yasuo

Proceedings in Radiochemistry, 1(1), p.71 - 74, 2011/09

Solvent cleanup method using activated alumina was discussed in this study. This method was one of candidate to remove TBP/$$n$$-dodecane degradation products. The degradation sample of 30% TBP/$$n$$-dodecane was prepared by irradiation (1.6 MGy) using $$^{60}$$Co $$gamma$$-source. The absorbed dose for sample was almost 1.6 MGy. The degradation products were qualitatively analyzed by gas chromatography-mass spectrometer (GC-MS). After the irradiation, solvent cleanup was performed by activated alumina and the cleanup using alumina was examined by phase separation test with 3M HNO$$_{3}$$. As the result, it was found that hexane and long-chain alcohols were mainly generated as the n-dodecane degradation products by irradiation, and almost 70% of the TBP/$$n$$-dodecane degradation products were removed and the phase separation performance were improved by the cleanup using activated alumina.

Journal Articles

Water diffusion in fluoropolymer-based fuel-cell electrolyte membranes investigated by radioactivated-tracer permeation technique

Sawada, Shinichi; Yamaki, Tetsuya; Asano, Masaharu; Suzuki, Akihiro*; Terai, Takayuki*; Maekawa, Yasunari

Proceedings in Radiochemistry, 1(1), p.409 - 413, 2011/09

In polymer electrolyte fuel cells, the water transport properties of the polymer electrolyte membranes (PEMs) would affect the cell performance. In this study, we investigated the self-diffusion coefficient of water molecules in the PEMs by using radioactivated-tracer permeation technique. The PEMs were synthesized from crosslinked-polytetrafluoroethylene (cPTFE) by the radiation-induced grafting method. The Dw of the PEMs increased with their ion exchange capacities (IECs), and reached the maximum value of 3.7$$times$$10$$^{-10}$$m$$^{2}$$/s at the IEC of 2.4 meq/g. interestingly, commercially-available Nafion membrane exhibited the highest Dw of 4.9$$times$$10$$^{-10}$$m$$^{2}$$/s despite of its low IEC. The lower Dw in the cPTFE PEMs is probably attributed to the geometry of hydrophilic regions phase-separated from the surrounding hydrophobic polymers.

Journal Articles

Isotope production for medical usage using fast neutron reactions

Hatsukawa, Yuichi; Nagai, Yasuki; Kin, Tadahiro; Segawa, Mariko; Harada, Hideo; Iwamoto, Osamu; Iwamoto, Nobuyuki; Ochiai, Kentaro; Takakura, Kosuke; Konno, Chikara; et al.

Proceedings in Radiochemistry, 1(1), p.327 - 329, 2011/09

Authors proposed a new route to produce $$^{99}$$Mo by the $$^{100}$$Mo($$n$$,2$$n$$)$$^{99}$$Mo reaction, which has some characteristic features. Such as the reaction cross section is large, about 1.5 barn at 12 $$<$$ $$E$$$$_{rm n}$$ $$<$$ 17 MeV, which is 10 times larger than the thermal-neutron capture cross section of $$^{98}$$Mo. Second, the cross sections of the ($$n$$,$$alpha$$), ($$n$$,$$np$$), and ($$n$$,$$p$$) reactions are less than a few mb at $$E$$$$_{rm n}$$ = 14 MeV. Third, a large amount of $$^{100}$$Mo target materials can be used, compared to that for proton beam irradiation on $$^{100}$$Mo. Fourth, intense neutrons with energy of 12-17 MeV are already available. In the present work we have measured all $$gamma$$-rays emitted from activities produced by bombarding a natural Mo target with neutrons from the D($$^3$$H,$$n$$)$$^4$$He reaction at Fusion Neutronics Source Facility (FNS) at Japan Atomic Energy Agency (JAEA) to study characteristic features mentioned above more in detail. The neutron flux was about 10$$^{12}$$n/cm$$^2$$s. The experimental results at FNS will be discussed in the conference.

Journal Articles

Using soils for accident dosimetry; A Preliminary study using optically stimulated luminescence from quartz

Fujita, Hiroki; Jain, M.*; Murray, A. S.*

Proceedings in Radiochemistry, 1(1), p.45 - 48, 2011/09

Single-aliquot regenerative OSL (SAR OSL) method was developed specifically for measuring background dose in natural quartz extracted from soils collected around Tokai-mura. The objective was to assess the potential of using soils for retrospective assessment of a radiation accident. The SAR data showed good reproducibility and dose recovery, and there were no evidence of fading of quartz signal based on the "delayed" dose recovery experiments. The dose of minimum detection limit (MDL) was 0.1 Gy. The background doses were generally the range of the MDL - few Gy, and no clear trend in dose depth profile was observed. An absence of clear trend might be indicative of ongoing soil activity resulting remixing of grains from the surface. From these results, we conclude that the SAR OSL dosimetry using natural quartz extracted from soil could evaluate accident dose.

Journal Articles

EXAFS analysis of uranium(IV) and thorium(IV) complexes in concentrated CaCl$$_{2}$$ solutions

Uehara, Akihiro*; Fujii, Toshiyuki*; Matsuura, Haruaki*; Sato, Nobuaki*; Nagai, Takayuki; Minato, Kazuo; Yamana, Hajimu*; Okamoto, Yoshihiro

Proceedings in Radiochemistry, 1(1), p.161 - 165, 2011/09

Journal Articles

Validation of ecological $$^{131}$$I transfer models using experimental data of the "Plavsk scenario"

Zvonova, I.*; Krajewski, P.*; Berkovskyy, V.*; Ammann, M.*; Duffa, C.*; Filistovic, V.*; Homma, Toshimitsu; Kany$'a$r, B.*; Nedveckaite, T.*; Simon, S.*; et al.

Proceedings of 7th International Conference on Nuclear and Radiochemistry (NRC-7) (CD-ROM), 5 Pages, 2008/08

Journal Articles

Phoswich detection system applying optical techniques for actinide monitoring

Usuda, Shigekazu; Yasuda, Kenichiro

Proceedings of 5th International Conference on Nuclear and Radiochemistry (NRC5), 2, p.595 - 598, 2000/00

no abstracts in English

Journal Articles

The Study of In Situ Radionuclide Retardation in the Geosphere: Examples from Nagra's Grimsel Test Site, Switzerland

; McKinl, I. G.*; Mori, A.*; Frieg, B.*; W.Kickmaie*

Proceedings of International Conference on Nuclear and Radiochemistry, 0 Pages, 2000/00


Journal Articles

Thermal Neutron Cross Section and Resonance Integral of the Reaction 135Cs(n,r)136Cs

Harada, Hideo; Nakamura, Shoji; Kato, Toshio; Kobayashi, Katsunori*; Motoishi, Shoji*; Tanase, Masakazu*

Proceedings of Asia-Pacific Symposium on Radiochemistry (APSORC '97), 0 Pages, 1997/00


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