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JAEA Reports

XAFS measurement of simulated waste glass samples (Borosilicate glass including vanadium)

Nagai, Takayuki; Kobayashi, Hidekazu; Sasage, Kenichi; Ayame, Yasuo; Okamoto, Yoshihiro; Shiwaku, Hideaki; Matsuura, Haruaki*; Uchiyama, Takafumi*; Okada, Yukiko*; Nezu, Atsushi*; et al.

JAEA-Research 2016-015, 52 Pages, 2016/11


The local structure of waste elements in simulated waste glasses including V was estimated by using synchrotron XAFS measurement in this study. The results are as follows. (1) V has a high possibility which exists in the glass phase in the case of frit, and V can regard both samples as stable 4 coordination structure. (2) Zn, Ce, Nd, Zr, and Mo exist in the glass phase, and the difference is admitted by the percentage of Ce(III) and Ce(IV) by the composition. (3) Ru is separated from the glass phase as RuO$$_{2}$$ crystalline, both of metal and oxide exist in Rh, and Pd is separated out as metal. (4) It was confirmed that the regularity of the local structure of Zr and Mo in the molten glasses retreats as a result of the XAFS measurement at high temperature. (5) The XAFS measurement of molten glasses were performed at 1200$$^{circ}$$C, so it would be possible to acquire excellent data by improving the shapes of the sample cell.

Journal Articles

Structural investigation of thorium in molten lithium-calcium fluoride mixtures for salt treatment process in molten salt reactor

Numakura, Masahiko*; Sato, Nobuaki*; Bessada, C.*; Okamoto, Yoshihiro; Akatsuka, Hiroshi*; Nezu, Atsushi*; Shimohara, Yasuaki*; Tajima, Keisuke*; Kawano, Hirokazu*; Nakahagi, Takeshi*; et al.

Progress in Nuclear Energy, 53(7), p.994 - 998, 2011/11

 Times Cited Count:13 Percentile:69.86(Nuclear Science & Technology)

X-ray absorption fine structure (XAFS) measurements on thorium fluoride in molten lithium-calcium fluoride mixtures and molecular dynamics (MD) simulation of zirconium and yttrium fluoride in molten lithium-calcium fluoride mixtures have been carried out. In the molten state, coordination number of thorium and inter ionic distances between thorium and fluorine in the first neighbor are nearly constant in all mixtures. However the fluctuation factors (Debye-Waller factor and C$$_3$$ cumulant) increase until $$x$$CaF$$_2$$ = 0.17 and decrease by addition of excess CaF$$_2$$. It means that the local structure around Th$$^{4+}$$ is disordered until $$x$$CaF$$_2$$=0.17 and stabilized over $$x$$CaF$$_2$$ = 0.17. The variation of fluctuation factors is related to the number density of F$$^-$$ in ThF$$_4$$ mixtures and the stability of local structure around Th$$^{4+}$$ increases with decreasing the number density of F$$^-$$ in ThF$$_4$$ mixtures. This tendency is common to those in the ZrF$$_4$$ and YF$$_3$$ mixtures.

Oral presentation

Structural analysis of molten TbF$$_3$$-LiF

Numakura, Masahiko*; Bessada, C.*; Ory, S.*; Rakhamatullin, A.*; Akatsuka, Hiroshi*; Nezu, Atsushi*; Yaita, Tsuyoshi; Okamoto, Yoshihiro; Shiwaku, Hideaki; Matsuura, Haruaki*

no journal, , 

To investigate the local structure of molten TbF$$_3$$ - LiF (x[TbF$$_3$$ = 0.2), X-ray absorption fine structure technique (XAFS) was applied using by BL11XU in SPring-8. By several analyses, e.g. X-ray diffraction and differential scanning calorimetry, it had been confirmed that TbF$$_{3}$$ and boron nitride reacted at less than 1073 K even under helium gas flow environment, thus, we focused on the spectrum obtained below 1073 K. According to the curve fitting, the interionic distance obtained from the data of heating between 933 K and 1013 K was shorter than solid state. It would be surely molten state of TbF$$_3$$ - LiF (x[TbF$$_3$$] = 0.2), since the value of distance obtained, i.e. 2.26${AA}$ corresponds to the sum of ionic radii of Tb$$^{3+}$$ and F$$^-$$.

Oral presentation

Integration of minor actinide separation process; EXAFS analysis of rare earth elements absorbed at the surface of various adsorbents

Matsuura, Haruaki*; Nezu, Atsushi*; Arai, Tsuyoshi*; Ono, Shimpei*; Sano, Yuichi; Watanabe, So

no journal, , 

no abstracts in English

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