Chemical species of cesium and iodine in condensed vaporized microparticles formed by melting nuclear fuel components with concrete materials

Onuki, Toshihiko*; Ye, J.*; Kato, Tomoaki; Liu, J.; Takano, Masahide; Kozai, Naofumi; Utsunomiya, Satoshi*

Environmental Science; Processes & Impacts, 25(7), p.1204 - 1212, 2023/07

https://doi.org/10.1039/D3EM00074E

To elucidate chemical forms of Cs and I in microparticles produced via the Fukushima Daiichi Nuclear Power Plant accident and released into the atmosphere, we analyzed Cs and I in condensed vaporized particles (CVP) produced by melting experiments using nuclear fuel components containing CsI with concrete. CVPs consisted of many round particles containing Cs and I of diameters less than several tens of micrometers. Two kinds of particles were present: one containing large amounts of Cs and I, suggesting the presence of CsI, and the other containing small amounts of Cs and I with large Si contents. Most of CsI from both particles were dissolved in water. On the contrary, some fractions of Cs remained from the latter particles. These results suggest that Cs was incorporated in CVPs along with Si to form water low-soluble CVPs

Preliminary studies of XANES and DFT calculation of Ru extraction by imino-diacetamide and related compounds

Sasaki, Yuji; Nakase, Masahiko*; Kaneko, Masashi; Kobayashi, Toru; Takeshita, Kenji*; Matsumiya, Masahiko*

Analytical Sciences, 5 Pages, 2023/00

https://doi.org/10.1007/s44211-023-00453-y

We conducted three field researches on Ru-extraction, XANES, and DFT-calculation. The order of the distribution ratio, D(Ru), from acid, HCl HSO HNO HClO, by MIDOA is studied by XANES spectra, which indicates the valency change of Ru in HCl media and supports the ion pairing extraction of anionic Ru ion and cationic MIDOA. The same extractant trend, NTAamide MIDOA IDOA, due to D values as the energy gap of HOMO and LUMO could be found by DFT calculation, which suggests that the reaction heat has a positive correlation with extractability for extractant.

Sorption behavior of selenide on montmorillonite

Sugiura, Yuki; Tomura, Tsutomu*; Ishidera, Takamitsu; Doi, Reisuke; Francisco, P. C. M.; Shiwaku, Hideaki; Kobayashi, Toru; Matsumura, Daiju; Takahashi, Yoshio*; Tachi, Yukio

Journal of Radioanalytical and Nuclear Chemistry, 324(2), p.615 - 622, 2020/05

https://doi.org/10.1007/s10967-020-07092-x

Preliminary evaluation of local structure and speciation of lanthanoids in aqueous solution, iron hydroxide, manganese dioxide, and calcite using the L-Edge X-ray absorption near edge structure spectra

Ota, Atsuyuki*; Tanaka, Kazuya; Tsuno, Hiroshi*

Journal of Physical Chemistry A, 122(41), p.8152 - 8161, 2018/10

https://doi.org/10.1021/acs.jpca.8b06168

We investigated the application of L-edge XANES spectra to the local structural analysis of lanthanoids in aqueous solution, iron hydroxide, manganese dioxide, and calcium carbonate. For each lanthanoid, the full width at half maximum (FWHM) values of lanthanoid compounds roughly decreased with increasing coordination numbers. However, they did not strictly reflect the local coordination sphere of the lanthanoid complex, but were rather sensitive to their chemical forms. The relationship between the magnitude of the FWHM values was determined by the crystal field splitting or degeneracy of 5d orbitals. The systematic variation of FWHM can be explained by the ligand strength of the ligand molecules (-HO, -O, -OH, -CO, -Cl, and -O) that cause the crystal field splitting. Therefore, the FWHM values of L-edge XANES of lanthanoid compounds may be more useful in speciation analysis rather than structural analysis such as EXAFS.

Difference between Cr and Ni K-edge XANES spectra of rust layers formed on Fe-based binary alloys exposed to Cl-rich environment

Konishi, Hiroyuki; Yamashita, Masato*; Uchida, Hitoshi*; Mizuki, Junichiro

Materials Transactions, 46(1), p.136 - 139, 2005/01

https://doi.org/10.2320/matertrans.46.136

The rust layer formed on weathering steel possesses a strong protective ability against corrosives in an atmosphere. This ability is related to the structure of the rust layer. The difference in the protective ability of a rust layer in a Cl-rich environment between conventional weathering steel containing Cr and advanced weathering steel containing Ni is believed to be caused by the differences in local structural and chemical properties between alloying elements, Cr and Ni, in the rust layer. In order to examine the effect of these alloying elements on the structure of the rust layer formed on steel in a Cl-rich environment, we have performed Cr and Ni K-edge X-ray absorption near-edge structure (XANES) measurements for the rust layer of Fe-Cr and Fe-Ni binary alloys exposed to a Cl-rich atmosphere using synchrotron radiation. The results of the Cr K-edge XANES measurements for the rust layer of Fe-Cr binary alloys show that the atomic geometry around Cr depends on the concentration of Cr. Therefore, it is expected that the local structure around Cr in the rust layer is unstable. On the other hand, from the results of the Ni K-edge XANES measurements for the rust layer of Fe-Ni binary alloys, Ni is considered to be positioned at a specific site in the crystal structure of a constituent of the rust layer, such as akaganite or magnetite. As a consequence, Ni negligibly interacts with Cl ions in the rust layer.

EPR studies of 5-bromouracil crystal after irradiation with X rays in the bromine K-edge region

Yokoya, Akinari; Takakura, Kaoru*; Watanabe, Ritsuko; Akamatsu, Ken*; Ito, Takashi*

Radiation Research, 162(4), p.469 - 473, 2004/10

https://doi.org/10.1667/RR3230

X-ray absorption spectra from single crystals of 5-Bromouracil were measured with the transmission mode in the energy range from 13.41 to 13.50 keV using the linearly polarized synchrotron radiation (SR). A characteristic resonance structure, consisting of four peaks, was recognized in the spectra in the Br K-edge region. The intensities of these peaks were strongly dependent on the crystal rotation about the normal of the crystal b-c plane, which was set perpendicular to the X-ray beam direction. (SR X-rays are polarized in the horizontal plane.) Molecular orbital calculations indicate that these resonance peaks are associated with the transitions from the 1s electron of Br to the Br-C molecular antibonding orbitals and to a shape resonance. The observed anisotropy of each photoabsorption peak might originate from the angular dependences of these molecular orbitals.

Element-specific and site-specific ion desorption from adsorbed molecules by deep core-level photoexcitation at the -edges

Baba, Yuji

Low Temperature Physics, 29(3), p.228 - 242, 2003/03

https://doi.org/10.1063/1.1542444

no abstracts in English

Electron paramagnetic resonance induced by K-shell resonance excitation in DNA bases in solid state

Yokoya, Akinari; Akamatsu, Ken*; Fujii, Kentaro

Nuclear Instruments and Methods in Physics Research B, 99, p.366 - 369, 2003/01

no abstracts in English

X-ray absorption study of molten uranium chloride system

Okamoto, Yoshihiro; Akabori, Mitsuo; Ito, Akinori; Ogawa, Toru

Journal of Nuclear Science and Technology, 39(Suppl.3), p.638 - 641, 2002/11

http://www.tandfonline.com/doi/abs/10.1080/00223131.2002.10875549

We report local structural features of molten UCl with LiCl-KCl eutectic probed by the U L-edge XAFS(X-ray absorption fine structure). The XAFS measurements were performed in a transmission mode at the BL27B station of the Photon Factory(High Energy Accelerator Organization, Tsukuba, JAPAN). Sample prepared by chlorination of uranium hydride and then reduction with zinc powder was sealed in a quartz cell under reduced pressure. The nearest U-Cl distance and the coordination number of Cl around U ion were obtained by a curve fitting of the 1st shell XAFS function k(k). The pair potential in the U-Cl correlation was evaluated from XAFS simulation by combinational use of the MD and the FEFF8. In addition, valence state of uranium in the melt was evaluated by XANES(X-ray absorption near edge structure) spectra.

Study of metallofullerenes encapsulating actinides

Akiyama, Kazuhiko; Sueki, Keisuke*; Tsukada, Kazuaki; Yaita, Tsuyoshi; Miyake, Yoko*; Haba, Hiromitsu*; Asai, Masato; Kodama, Takeshi*; Kikuchi, Koichi*; Otsuki, Tsutomu*; et al.

Journal of Nuclear and Radiochemical Sciences, 3(1), p.151 - 154, 2002/06

https://doi.org/10.14494/jnrs2000.3.151

The oxidation state of actinide elements encapsulated in fullerenes is studied. HPLC elution behavior of actinide-fullerenes is classified into two groups; the elution behavior of the first group, encapsulating U, Np, and Am, is similar to that of the light lanthanide-fullerenes, such as La, Ce, Pr, and Nd, while the behavior of the second group, encapsulating Th and Pa, is quite different from that of any lanthanide-fullerenes. The chemical species in the main HPLC elution peak of each group were identified as M@C82 and M@C84 (M = metal atom) from the mass of the U and Th fullerenes, respectively. The oxidation states of the U and Th atoms in the fullerenes were deduced to be 3+ and 4+, respectively, from the UV/vis/NIR absorption and XANES spectroscopy.