Visualization of the accurate distribution of trace uranium in environmental sample using superconducting technology

Yomogida, Takumi; Yamada, Shinya*; Takahashi, Yoshio*

SPring-8/SACLA Research Frontiers 2024 (Internet), p.88 - 89, 2024/08

This article explains the recent research being carried out by our group on the application of superconducting transition edge sensors (TES) to detectors for synchrotron radiation X-ray analysis. We applied a TES spectrometer as a detector for microbeam X-ray measurements to determine uranium (U) distribution at the micro-scale and its chemical species in biotite obtained from the U mine. When using a conventional semiconductor detector, the X-ray fluorescence peaks of Rb and U overlap with each other due to the shortage of energy resolution. The conventional semiconductor detector could only observe the fluorescence X-ray of Rb K line, which is abundant in biotite, and could not accurately detect the signal of trace amounts of U. Meanwhile, the XRF peak of the U L line was fully separated from that of the Rb K line by using TES, which indicates that TES made it possible to perform ultra-high energy resolution analysis.

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

Micro- to nano-scale areal heterogeneity in pore structure and mineral compositions of a sub-decimeter-sized Eagle Ford Shale

Wang, Q.*; Hu, Q.*; Zhao, C.*; Yang, X.*; Zhang, T.*; Ilavsky, J.*; Kuzmenko, I.*; Ma, B.*; Tachi, Yukio

International Journal of Coal Geology, 261, p.104093_1 - 104093_15, 2022/09

https://doi.org/10.1016/j.coal.2022.104093

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

Alignment of grain orientation in polycrystalline-SiO films induced by high-energy heavy ions

Shinde, N. S.*; Matsunami, Noriaki*; Shimura, Tetsuo*; Sataka, Masao; Okayasu, Satoru; Kato, Teruo; Tazawa, Masato*

Nuclear Instruments and Methods in Physics Research B, 245(1), p.231 - 234, 2006/04

https://doi.org/10.1016/j.nimb.2005.11.107

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.

Synthesis and characterization of copper hydroxide acetate with a layered discoid crystal

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

Journal of Materials Research, 20(11), p.2997 - 3003, 2005/11

Layered transition metal hydroxide salt (LTMHS) is a group of anion-exchangeable layered compounds. LTMHSs have lately attraced attention of researchs on anion exchange and intercalation but very limited numbers of reports have been published on their synthesis, characteristics, and application. This study reports basic properties of a layered copper hyroxide acetate synthesized by a method modified from that of the previous studies. Titration of copper acetate solution with a dilute NaOH solution to pH 6.5 and subsequent aging at 313 K yielded a layered copper hydroxide acetate. This compound has some properties similar to those of the previously known copper hydroxide acetate, Cu(OH)(OCOCH)HO. The present copper hydroxide acetate is dissimilar to the previous compound in morphology, stability of bonding between the interlayer acetate ions and the matrix hydroxides, and reaction with anions in aqueous solutions.

Evaluation of permeated hydrogen through heat transfer pipes of the intermediate heat exchanger during the initial 950C operation of the HTTR

Sakaba, Nariaki; Matsuzawa, Takaharu*; Hirayama, Yoshiaki*; Nakagawa, Shigeaki; Nishihara, Tetsuo; Takeda, Tetsuaki

Proceedings of 2005 International Congress on Advances in Nuclear Power Plants (ICAPP '05) (CD-ROM), 8 Pages, 2005/05

The permeation of hydrogen isotopes through the Hastelloy XR high-temperature alloy adopted for the heat exchanger pipes of the intermediate heat exchanger in the HTTR (High Temperature Engineering Test Reactor) is one of the concerns in the hydrogen production system, which will be connected to the HTTR in the near future. An evaluation of the hydrogen permeation between the primary and secondary coolant through the Hastelloy XR was performed using the hydrogen concentration data observed during the initial 950C operation of the HTTR. The hydrogen permeability of the Hastelloy XR was estimated conservatively high as follows. The activation energy E and pre-exponential factor F of the permeability of hydrogen were E = 62 kJ/mol and F = 3.610 cm(NTP)/(cm s Pa), respectively, in the temperature range from 735K to 940K. The results implied that some oxidized film had been formed on the surface of the heat exchanger pipes of the intermediate heat exchanger.