Flexible waste management system for the future application of MA P&T technology to the current high-level liquid waste

Fukasawa, Tetsuo*; Suzuki, Akihiro*; Endo, Yoichi*; Inagaki, Yaohiro*; Arima, Tatsumi*; Muroya, Yusa*; Endo, Keita*; Watanabe, Daisuke*; Matsumura, Tatsuro; Ishii, Katsunori; et al.

Journal of Nuclear Science and Technology, 61(3), p.307 - 317, 2024/03

https://doi.org/10.1080/00223131.2023.2226673

A flexible waste management system (FWM) is being developed to apply future MA partitioning and transmutation (P&T) technology to current HLLW. This FWM system will store high-level waste (HLLW) in granular form until MA partitioning and transmutation technology is realized. The feasibility of the main process was essentially confirmed by basic experiments and preliminary thermal analysis for granule production by rotary kiln from simulated HLLW and for temporary storage (50 years) of HLW granules at the HLW storage facility, respectively. The granule production experiments revealed that relatively large particles can be produced by the rotary kiln. The results of the thermal analysis showed that the small diameter canisters could be used to safely store the granules at a higher storage density than vitrified HLW. The effectiveness of the FWM system in terms of potential radiotoxicity and repository area was also evaluated, and it was shown that FWM can reduce these factors and has significant advantages in the disposal of HLW generated in current reprocessing plants. Since LWR fuel is stored for a long period of time in Japan and the operation of a reprocessing plant is expected to start soon, the FWM system is considered to be an effective system for reducing the environmental burden of HLW disposal.

Local Ir dedimerization followed by ligand-hole hopping in X-ray irradiated thiospinel

Hiraka, Haruhiro*; Matsumura, Daiju; Horigane, Kazumasa*; Mizuki, Junichiro*

Journal of Physics and Chemistry of Solids, 150, p.109870_1 - 109870_8, 2021/03

https://doi.org/10.1016/j.jpcs.2020.109870

Electrochemical adsorption on Pt nanoparticles in alkaline solution observed using in situ high energy resolution X-ray absorption spectroscopy

Kusano, Shogo*; Matsumura, Daiju; Ishii, Kenji*; Tanaka, Hirohisa*; Mizuki, Junichiro*

Nanomaterials (Internet), 9(4), p.642_1 - 642_14, 2019/04

https://doi.org/10.3390/nano9040642

Analytical studies of three-dimensional evaluation of radionuclide distribution in zeolite wastes through gamma scanning of adsorption vessels

Matsumura, Taichi; Nagaishi, Ryuji; Katakura, Junichi*; Suzuki, Masahide*

Nuclear Science and Engineering, 192(1), p.70 - 79, 2018/10

https://doi.org/10.1080/00295639.2018.1493856

The gamma-scanning of SDS (submerged demineralizer system) vessel used as a typical vessel for decontamination of radioactive water at Three Mile Island Unit 2 (TMI-2) accident was simulated in the axial and radial directions of real and cylindrical-shaped vessels by using a Monte Carlo calculation code (PHITS) on the basis of the geometrical and compositional information of vessel and gamma-scanning available in the previous reports at the accident. In the axial simulation, the true distribution of radioactive Cs in the zeolite packed bed of vessel was successfully evaluated when a correction function derived from a virtual constant distribution of Cs was applied to the reported gamma-scanning profile. In the radial simulation, the virtual disk-formed and shell-formed sources of Cs displaced in the packed bed were clearly observed from the top and bottom views of vessel. This new radial gamma-scanning indicates that the radial localization of Cs could be well observed by measuring gamma-ray from the top view of vessel during storage. We further examined the radial gamma-scanning from the side view whether the radial localization of Cs can be confirmed in the normally existing gamma-scanning room or not.

Towards optimizing the performance of self-regenerating Pt-based perovskite catalysts

Jarrige, I.*; Ishii, Kenji; Matsumura, Daiju; Nishihata, Yasuo; Yoshida, Masahiro*; Kishi, Hirofumi*; Taniguchi, Masashi*; Uenishi, Mari*; Tanaka, Hirohisa*; Kasai, Hideaki*; et al.

ACS Catalysis, 5(2), p.1112 - 1118, 2015/02

https://doi.org/10.1021/cs501608k

200 Hz observation of hydrogenation reaction of Pd nanoparticles by using dispersive XAFS optics

Matsumura, Daiju; Okajima, Yuka*; Nishihata, Yasuo; Mizuki, Junichiro

Journal of Physics; Conference Series, 430, p.012024_1 - 012024_6, 2013/04

https://doi.org/10.1088/1742-6596/430/1/012024

Dynamic structural change in Pd-perovskite automotive catalyst studied by time-resolved dispersive X-ray absorption fine structure

Matsumura, Daiju; Nishihata, Yasuo; Mizuki, Junichiro; Taniguchi, Masashi*; Uenishi, Mari*; Tanaka, Hirohisa*

Journal of Applied Physics, 107(12), p.124319_1 - 124319_5, 2010/06

https://doi.org/10.1063/1.3437084

The structural transformation of a Pd-perovskite automotive catalyst, LaFePdO, which has a high catalytic activity during aging, was studied by in situ time-resolved dispersive X-ray absorption fine structure spectroscopy at 473-773 K. An AlO-based conventional catalyst was also studied. In a reductive atmosphere, both catalysts showed similar temperature dependences of structural transformation from an oxide to a metal. However, different temperature dependence was observed in an oxidative atmosphere. A faster response in the structural change was observed in the Pd-perovskite catalyst than in the Pd/AlO catalyst. It was revealed that Pd-perovskite shows a considerably fast structural change to the oxidized state via the movement of Pd atoms into the perovskite crystal, in comparison with Pd/AlO showing two-step structural change for making PdO.

Fe-doping effects on magnetism in hole-type superconductors of (Bi,Pb)SrCuO

Hiraka, Haruhiro*; Wakimoto, Shuichi; Takeda, Masayasu; Kakurai, Kazuhisa; Matsumura, Daiju; Nishihata, Yasuo; Mizuki, Junichiro; Yamada, Kazuyoshi*

Journal of Physics; Conference Series, 200, p.012059_1 - 012059_4, 2010/02

https://doi.org/10.1088/1742-6596/200/1/012059

We studied Fe-dopant effects on spin correlations in BiPbSrCuO. Magnetic neutron elastic scattering, which is absent in a pristine sample, has been observed at incommensurate positions with an incommensurability of 0.2. Surprisingly, this anomalously large follows a linear relation even in the overdoped region, unlike for LaSrCuO. We discuss this specific feature observed in the overdoped phase from a dynamical stripe viewpoint.

Dynamic structural change of Pd particles on LaFeO under redox atmosphere and CO/NO catalytic reaction studied by dispersive XAFS

Matsumura, Daiju; Okajima, Yuka; Nishihata, Yasuo; Mizuki, Junichiro; Taniguchi, Masashi*; Uenishi, Mari*; Tanaka, Hirohisa*

Journal of Physics; Conference Series, 190, p.012154_1 - 012154_6, 2009/11

https://doi.org/10.1088/1742-6596/190/1/012154

Pd/LaFeO is known to keep the metal particle size small even after the long time redox processes because Pd atoms make complex oxide with LaFeO perovskite-type crystal under the oxidative atmosphere. We observed the local structure of Pd atoms by dispersive optics from the viewpoint of dynamical structure change of Pd during metal-oxide change and CO-NO catalytic reaction. It was recognized that, under the reductive atmosphere, Pd atoms show similar speed of movement from oxide to metal state both on LaFeO and AlO. However, under the oxidative atmosphere, Pd atoms on LaFeO show faster movement from metal to oxide state with single reaction step than those on AlO with two-step oxidation. In addition, many differences in structure and shape between Pd particles on LaFeO and AlO are observed.

Local structure anomaly around Ge dopants in MnCuGeN with negative thermal expansion

Matsuno, Jobu*; Takenaka, Koshi*; Takagi, Hidenori*; Matsumura, Daiju; Nishihata, Yasuo; Mizuki, Junichiro

Applied Physics Letters, 94(18), p.181904_1 - 181904_3, 2009/05

https://doi.org/10.1063/1.3129169

Local structure analysis of Cu and Ge atoms in the negative thermal expansion material MnCuGeN was conducted using X-ray absorption fine structure measurements. The temperature dependence of the interatomic distance was found to reflect the macroscopic negative thermal expansion both for Cu-Mn and Ge-Mn shells, although the magnitude of the relative change was much larger for Ge-Mn than Cu-Mn. An enhanced anomaly of the Debye-Waller factor was observed for the Ge-Mn shell in the temperature region of the negative expansion, indicating the presence of static local disorder around Ge impurities. These local structure anomalies strongly suggest that the local and inhomogeneous strain around Ge is essential in broadening the discontinuous volume contraction.