Sintering and microstructural behaviors of mechanically blended Nd/Sm-doped MOX

Hirooka, Shun; Horii, Yuta; Sunaoshi, Takeo*; Uno, Hiroki*; Yamada, Tadahisa*; Vauchy, R.; Hayashizaki, Kohei; Nakamichi, Shinya; Murakami, Tatsutoshi; Kato, Masato

Journal of Nuclear Science and Technology, 60(11), p.1313 - 1323, 2023/11

https://doi.org/10.1080/00223131.2023.2192725

Additive MOX pellets are fabricated by a conventional dry powder metallurgy method. NdO and SmO are chosen as the additive materials to simulate the corresponding soluble fission products dispersed in MOX. Shrinkage curves of the MOX pellets are obtained by dilatometry, which reveal that the sintering temperature is shifted toward a value higher than that of the respective regular MOX. The additives, however, promote grain growth and densification, which can be explained by the effect of oxidized uranium cations covering to a pentavalent state. Ceramography reveals large agglomerates after sintering, and Electron Probe Micro-Analysis confirms that inhomogeneous elemental distribution, whereas XRD reveals a single face-centered cubic phase. Finally, by grinding and re-sintering the specimens, the cation distribution homogeneity is significantly improved, which can simulate spent nuclear fuels with soluble fission products.

Difference in expansion and dehydration behaviors between NH- and K-montmorillonite

Kawakita, Ryohei; Saito, Akito*; Sakuma, Hiroshi*; Anraku, Sohtaro; Kikuchi, Ryosuke*; Otake, Tsubasa*; Sato, Tsutomu*

Applied Clay Science, 231, p.106722_1 - 106722_7, 2023/01

https://doi.org/10.1016/j.clay.2022.106722

Evaluation on the crystal structure of ningyoite using XRD analysis and DFT calculation

Suzuki, Chikashi; Osaka, Masahiko; Nakagiri, Toshio

Proceedings of Joint International Conference on Supercomputing in Nuclear Applications + Monte Carlo 2020 (SNA + MC 2020), p.131 - 136, 2020/10

In order to evaluate uranium migration behavior in Ningyo-toge area, we are examining the stability of uranium minerals using DFT calculation. As the first step, we investigated the crystal structure and unit cell composition of ningyoite with its structural details unclear, which is a major uranium mineral there. We analyzed the reported XRD pattern of ningyoite to evaluate a crystal structure of ningyoite using XRD analysis code. This XRD analysis indicates that the distance between U atoms is along axis. We constructed the structure of [CaU(PO)] with three U or Ca atoms aligned along axis on the basis of this examination, and conducted structural optimization with this structure as initial one using DFT calculation. The theoretical XRD pattern has the maximum peak near 30, which the reported XRD pattern of ningyoite has. This result suggests that the structure of ningyoite is based on that of [CaU(PO)].

Investigation of ruthenium compounds in the vitrification process condition

Nagai, Takayuki; Sato, Nobuaki*; Sasage, Kenichi

Busshitsu, Debaisu Ryoiki Kyodo Kenkyu Kyoten Kenkyu Seika Hokokusho (Heisei-27-Nendo) (CD-ROM), 2 Pages, 2016/03

no abstracts in English

Synthesis and characterization of nickel-copper hydroxide acetate, NiCu(OH)(OCOCH) 0.9HO

Kozai, Naofumi; Mitamura, Hisayoshi; Fukuyama, Hiroyasu; Esaka, Fumitaka; Komarneni, S.*

Microporous and Mesoporous Materials, 89(1-3), p.123 - 131, 2006/03

https://doi.org/10.1016/j.micromeso.2005.10.015

Layered transition metal hydroxide salt (LTMHS) is a group of anion-exchangeable layered compounds. Although LTMHSs have recentely attracted attention of researches on anion exchange and intercalation, very limited numbers of reports have been published on their synthesis, characteristics, and applications. This paper describes basic characteristics of a new LTMHS, nickel-copper hydroxide acetate. Hydrothermal Heating of an aqueous solution containing nickel acetate, copper acetate, and hydrogen peroxide to 150C for 4h yielded a layered compound with an analytical composition of NiCu(OH)(OCOCH) 0.9HO. This compound does not take up Cl and NO in aqueous solution but takes up multivalent anions and shows high selectivity in uptake of toxic SeO and AsO. This compound may find applicarion in the removal of those toxic anions form natural water and wastewater rich in Cl and NO.

Preparation of crosslinked fluoropolymer electrolyte membranes for use in fuel cells and then investigated their structural properties

Inoue, Yutaka; Kobayashi, Kazuhiro; Yamaki, Tetsuya; Asano, Masaharu; Kubota, Hitoshi*; Yoshida, Masaru

Dai-2-Kai 21-Seiki Rengo Shimpojiumu; Kagaku Gijutsu To Ningen Rombunshu, p.257 - 260, 2003/00

We prepared crosslinked fluoropolymer electrolyte membranes for use in fuel cells and then investigated their structural properties by X-ray diffraction (XRD) analysis. The radiation-induced grafting of styrene into crosslinked polytetrafluoroethylene (PTFE) films and subsequent sulfonation enabled us to obtain the electrolyte membrane with a sufficient ion exchange capacity, which exceeds that of the commercially-available film, Nafion. As the crosslinking and styrene grafting reactions proceeded, the size of the PTFE crystallites in the film became smaller, thereby decreasing the film crystallinity. Interestingly, in contrast to Nafion, the resulting sulfonated membranes were found to have high crystallinity.

Study of a new ytterbium doped phosphate laser glass

Dai, S.*; Hu, L.*; Sugiyama, Akira; Izawa, Yasukazu*; Liu, Z.*; Jiang, Z.*

Chinese Science Bulletin, 47(3), p.255 - 259, 2002/02

https://doi.org/10.1360/02tb9062

A new type of ytterbium doped phosphate laser glass has been produced and studied about physical and optical properties such as thermo-mechanical properties, nonlinear properties, crystalline phase, micro defects and spectroscopic properties. In the glass forming process, newly developed OH removing technology was adopted. From the reduction of OH concentration in the glass, upper state fluorescence lifetime reached 2.2 ms. Additionally, the glass shows remarkable athermal property of 0.4210E/K, which is around one-tenth of QX/Yb glass.

Preparation of epitaxial TiO films by pulsed laser deposition technique

Yamamoto, Shunya; Sumita, Taishi; Sugiharuto; Miyashita, Atsumi; Naramoto, Hiroshi

Thin Solid Films, 401(1-2), p.88 - 93, 2001/12

https://doi.org/10.1016/S0040-6090(01)01636-4

The epitaxial growth of high-quality TiO films has attracted much interest from the viewpoints of basic science and applications. In this study, it is shown that TiO films with anatase and rutile structure can be prepared by pulsed laser deposition (PLD) with a Nd-YAG laser under the controlled O atmosphere. The TiO films with 200 nm thickness were prepared on the SrTiO, LaAlO, LSAT and -AlO single crystal substrates. The epitaxial films were analyzed by Rutherford backscattering spectrometry (RBS) combined with channeling and X-ray diffraction for the crystallographic relationships with the substrates. The high quality anatase TiO (001) films have been successfully prepared on the LaAlO (001), LSAT (001) and SrTiO (001) substrates about 500C substrate temperature. Also the high quality rutile TiO (100) and TiO (001) films were obtained on the -AlO (0001) and (100), respectively.

Development of new extractant utilized by coordination properties of diglycol amide (DGA) to trivalent curium and lanthanides

Yaita, Tsuyoshi

Proceedings of International Youth Nuclear Congress 2000 (CD-ROM), 4 Pages, 2000/00

no abstracts in English

Characterization of natural and synthesized FeTiO crystals with RBS/PIXE/XRD

R.Q.Zhang*; Yamamoto, Shunya; Dai, Z.*; Narumi, Kazumasa; Aoki, Yasushi*; Naramoto, Hiroshi; Miyashita, Atsumi

International Journal of PIXE, 7(3&4), p.265 - 275, 1997/00

https://doi.org/10.1142/S0129083597000308

no abstracts in English