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Journal Articles

REDOX state analysis of platinoid elements in simulated high-level radioactive waste glass by synchrotron radiation based EXAFS

Okamoto, Yoshihiro; Shiwaku, Hideaki; Nakada, Masami; Komamine, Satoshi*; Ochi, Eiji*; Akabori, Mitsuo

Journal of Nuclear Materials, 471, p.110 - 115, 2016/02

https://doi.org/10.1016/j.jnucmat.2016.01.008

Times Cited Count：6 Percentile：49.05(Materials Science, Multidisciplinary)

Extended X-ray Absorption Fine Structure (EXAFS) analyses were performed to evaluate REDOX (REDuction and OXidation) state of platinoid elements in simulated high-level nuclear waste glass samples prepared under different conditions of temperature and atmosphere. At first, EXAFS functions were compared with those of standard materials such as RuO. Then structural parameters were obtained from a curve fitting analysis. In addition, a fitting analysis used a linear combination of the two standard EXAFS functions of a given elements metal and oxide was applied to determine ratio of metal/oxide in the simulated glass. The redox state of Ru was successfully evaluated from the linear combination fitting results of EXAFS functions. The ratio of metal increased at more reducing atmosphere and at higher temperatures. Chemical form of rhodium oxide in the simulated glass samples was RhO unlike expected RhO. It can be estimated rhodium behaves according with ruthenium when the chemical form is oxide.

Journal Articles

Cabling technology of NbSn conductor for ITER central solenoid

Takahashi, Yoshikazu; Nabara, Yoshihiro; Ozeki, Hidemasa; Hemmi, Tsutomu; Nunoya, Yoshihiko; Isono, Takaaki; Matsui, Kunihiro; Kawano, Katsumi; Oshikiri, Masayuki; Uno, Yasuhiro; et al.

IEEE Transactions on Applied Superconductivity, 24(3), p.4802404_1 - 4802404_4, 2014/06

https://doi.org/10.1109/TASC.2013.2287311

Times Cited Count：26 Percentile：73.77(Engineering, Electrical & Electronic)

Japan Atomic Energy Agency (JAEA) is procuring all amounts of NbSn conductors for Central Solenoid (CS) in the ITER project. Before start of mass-productions, the conductor should be tested to confirm superconducting performance in the SULTAN facility, Switzerland. The original design of cabling twist pitches is 45-85-145-250-450 mm, called normal twist pitch (NTP). The test results of the conductors with NTP was that current shearing temperature (Tcs) is decreasing due to electro-magnetic (EM) load cycles. On the other hand, the results of the conductors with short twist pitches (STP) of 25-45-80-150-450 mm show that the Tcs is stabilized during EM load cyclic tests. Because the conductors with STP have smaller void fraction, higher compaction ratio during cabling is required and possibility of damage on strands increases. The technology for the cables with STP was developed in Japanese cabling suppliers. The several key technologies will be described in this paper.

Journal Articles

Synchrotron radiation-based X-ray imaging study of ruthenium in simulated high-level waste glass

Okamoto, Yoshihiro; Nakada, Masami; Akabori, Mitsuo; Shiwaku, Hideaki; Komamine, Satoshi*; Fukui, Toshiki*; Ochi, Eiji*; Nitani, Hiroaki*; Nomura, Masaharu*

Nihon Genshiryoku Gakkai Wabun Rombunshi, 11(2), p.127 - 132, 2012/06

https://doi.org/10.3327/taesj.J11.031

Distribution and the chemical state of Ru element in the simulated high-level waste glass were examined by using the synchrotron radiation based X-ray imaging technique. In this technique, a direct X-ray CCD camera is used in place of an ion chamber. Position sensitive X-ray absorption spectra were obtained by analyzing gray scale in images of the X-ray CCD camera. At first, we measured a test sample containing RuO and Ru metal powder. We successfully obtained information on the Ru distribution in the sample. In addition, the chemical state (oxide or metal ?) of each small Ru-rich spot was evaluated by the corresponding position sensitive XAFS spectrum. The imaging XAFS technique was applied to some simulated high-level waste glass samples. The Ru distribution of the glass sample and their chemical state were confirmed by image analyses. It can be seen that Ru element scattered in the glass sample exists as oxide RuO.

Journal Articles

Design, synthesis, and evaluation of [ $^{188}$ Re]Organorhenium-labeled antibody fragments with renal enzyme-cleavable linkage for low renal radioactivity levels

Uehara, Tomoya*; Koike, Miho*; Nakata, Hideo*; Hanaoka, Hirofumi*; Iida, Yasuhiko*; Hashimoto, Kazuyuki; Akizawa, Hiromichi*; Endo, Keigo*; Arano, Yasushi*

Bioconjugate Chemistry, 18(1), p.190 - 198, 2007/01

https://doi.org/10.1021/bc0602329

Times Cited Count：20 Percentile：55.17(Biochemical Research Methods)

Renal localization of radiolabeled antibody fragments constitutes a problem in targeted imaging and radiotherapy. To estimate the applicability of the molecular design to metallic radionuclides, [ $^{188}$ Re]tricarbonyl(cyclopentadienylcarbonate)rhenium ([ $^{188}$ Re]CpTR-COOH) was conjugated with maleoyl-glycyl-lysine to prepare [ $^{188}$ Re]CpTR-GK. The cleavage of the glycyl-lysine linkage of the compound generates a glycine conjugate of [ $^{188}$ Re]CpTR-Gly. [ $^{188}$ Re]CpTR-GK was conjugated to thiolated Fab fragments to prepare [ $^{188}$ Re]CpTR-GK-Fab. The biodistribution of radioactivity after injection of [ $^{188}$ Re]CpTR-GK-Fab was compared with that of [ $^{188}$ Re]CpTR-Fab. [ $^{188}$ Re]CpTR-GK-Fab exhibited significantly lower renal radioactivity levels than did [ $^{188}$ Re]CpTR-Fab. The analysis of urine samples collected for 6 h postinjection of [ $^{188}$ Re]CpTR-GK-Fab showed that [ $^{188}$ Re]CpTR-Gly was the major radiometabolite. In tumor-bearing mice, [ $^{188}$ Re]CpTR-GK-Fab significantly reduced renal radioactivity levels without impairing the radioactivity levels in tumor. These findings indicate that the molecular design of radioparmaceuticals labeled with metallic radionuclides can be useful by using a radiometal chelate of high inertness and by designing a radiometabolite of high urinary excretion when released from antibody fragments following cleavage of a glycyl-lysine linkage. This study also indicates that a change in chemical structure of a radiolabel attached to a glycyl-lysine linkage significantly affected enzymes involved in the hydrolysis reaction.