Local structure analysis of heavy fermion CePtGa with a honeycomb structure using extended X-ray absorption fine structure

Matsumoto, Yuji*; Watabe, Yuki*; Iesari, F.*; Osumi, Masakatsu*; Ota, Kyugo*; Haga, Yoshinori; Hatada, Keisuke*; Okajima, Toshihiko*

Metals, 15(4), p.436_1 - 436_13, 2025/04

https://doi.org/10.3390/met15040436

Materials science and fuel technologies of uranium and plutonium mixed oxide

Kato, Masato; Machida, Masahiko; Hirooka, Shun; Nakamichi, Shinya; Ikusawa, Yoshihisa; Nakamura, Hiroki; Kobayashi, Keita; Ozawa, Takayuki; Maeda, Koji; Sasaki, Shinji; et al.

Materials Science and Fuel Technologies of Uranium and Plutonium mixed Oxide, 171 Pages, 2022/10

https://doi.org/10.1201/9781003298205

Innovative and advanced nuclear reactors using plutonium fuel has been developed in each country. In order to develop a new nuclear fuel, irradiation tests are indispensable, and it is necessary to demonstrate the performance and safety of nuclear fuels. If we can develop a technology that accurately simulates irradiation behavior as a technology that complements the irradiation test, the cost, time, and labor involved in nuclear fuel research and development will be greatly reduced. And safety and reliability can be significantly improved through simulation of nuclear fuel irradiation behavior. In order to evaluate the performance of nuclear fuel, it is necessary to know the physical and chemical properties of the fuel at high temperatures. And it is indispensable to develop a behavior model that describes various phenomena that occur during irradiation. In previous research and development, empirical methods with fitting parameters have been used in many parts of model development. However, empirical techniques can give very different results in areas where there is no data. Therefore, the purpose of this study is to construct a scientific descriptive model that can extrapolate the basic characteristics of fuel to the composition and temperature, and to develop an irradiation behavior analysis code to which the model is applied.

PSTEP: Project for solar-terrestrial environment prediction

Kusano, Kanya*; Ichimoto, Kiyoshi*; Ishii, Mamoru*; Miyoshi, Yoshizumi*; Yoden, Shigeo*; Akiyoshi, Hideharu*; Asai, Ayumi*; Ebihara, Yusuke*; Fujiwara, Hitoshi*; Goto, Tadanori*; et al.

Earth, Planets and Space (Internet), 73(1), p.159_1 - 159_29, 2021/12

https://doi.org/10.1186/s40623-021-01486-1

The PSTEP is a nationwide research collaboration in Japan and was conducted from April 2015 to March 2020, supported by a Grant-in-Aid for Scientific Research on Innovative Areas from the Ministry of Education, Culture, Sports, Science and Technology of Japan. It has made a significant progress in space weather research and operational forecasts, publishing over 500 refereed journal papers and organizing four international symposiums, various workshops and seminars, and summer school for graduate students at Rikubetsu in 2017. This paper is a summary report of the PSTEP and describes the major research achievements it produced.

Multipole and superconducting state in PrIrZn probed by muon spin relaxation

Higemoto, Wataru; Ito, Takashi; Ninomiya, Kazuhiko; Onimaru, Takahiro*; Matsumoto, Keisuke*; Takabatake, Toshiro*

Physical Review B, 85(23), p.235152_1 - 235152_4, 2012/06

https://doi.org/10.1103/PhysRevB.85.235152

We performed muon spin rotation and relaxation measurements (SR) in caged structural heavy fermion system PrIrZn to elucidate magnetic and superconducting properties. Temperature independent SR spectra were observed below 1K, indicating that the phase transition at 0.11K is non-magnetic origin, most probably pure quadrupole ordering. In the superconducting phase, no sign of unconventional superconductivity, like a broken time reversal symmetry superconductivity, is seen below =0.05K. Moreover, we have observed spontaneous muon spin precession in a zero field in the paramagnetic phase below 15K, suggesting a novel coupling between Pr nuclei and muon realize in PrIrZn.

Doping effect on charge ordered structure in Mn-doped YbFeO

Matsumoto, Keisuke*; Koyama, Tsukasa*; Mori, Shigeo*; Yoshii, Kenji; Kambe, Takashi*; Ikeda, Naoshi*

IOP Conference Series; Materials Science and Engineering, 18(9), p.092047_1 - 092047_4, 2011/09

https://doi.org/10.1088/1757-899X/18/9/092047

Changes of charge ordered (CO) structure by partial substitution of Mn for Fe in YbFeO were investigated by a transmission electron microscope (TEM), incombination with conventional dielectric measurement. It is revealed that partial substitution of Mn for Fe in YbFeO destroyed drastically the CO structure with the wave vector of q=1/3 1/3 1/2. Consequently polar clustering structure giving rise to honeycomb-shaped diffuse streaks was found in YbFeMnO. The random distribution of polar clustering structure gives rise to characteristic broad dielectric dispersion.

Strain measurement under loading in laser weld on austenitic stainless steel using high-energy synchrotron radiation

Matsumoto, Keisuke*; Shobu, Takahisa; Akiniwa, Yoshiaki*; Yagi, Tsuyoshi*; Yamamoto, Masataka*

Zairyo, 57(7), p.654 - 659, 2008/07

https://doi.org/10.2472/jsms.57.654

Study on the prediction accuracy of nuclide generation and depletion with JENDL

Okumura, Keisuke; Oki, Shigeo*; Yamamoto, Munenari*; Matsumoto, Hideki*; Ando, Yoshihira*; Tsujimoto, Kazufumi; Sasahara, Akihiro*; Katakura, Junichi; Matsumura, Tetsuo*; Aoyama, Takafumi*; et al.

JAERI-Research 2004-025, 154 Pages, 2005/01

JAERI-Research-2004-025.pdf:19.46MB

This report summarizes the activity (FY2000-2003) of Working Group (WG) on Evaluation of Nuclide Generation and Depletion under Subcommittee on Nuclear Fuel Cycle of Japanese Nuclear Data Committee. In the WG, analyses of Post Irradiation Examinations have been carried out for UO and MOX fuels irradiated in PWRs, BWRs and FBRs, and for actinide samples irradiated in fast reactors, by using ORIGEN or more detailed calculation codes with their libraries based on JENDL-3.2, JENDL-3.3 and other foreign nuclear data files. From these results, current prediction accuracy and problems for evaluation of nuclide generation and depletion are discussed. Furthermore, this report covers other products of our activity; development of the ORIGEN libraries for PWR, BWR and FBR based on JENDL-3.3, study on introduction of neutron spectrum index to ORIGEN calculations, and results of questionnaire survey on desirable accuracy of ORIGEN calculations.

Meltwater behavior on the defrosting

Matsumoto, Ryosuke*; Fujikawa, Naoto*; Oda, Yutaka*; Kurita, Keisuke; Iikura, Hiroshi; Harayama, Isao

no journal, , 

no abstracts in English

Magnetic/dielectric properties and charge ordering phenomenain YbFeMnO, 2

Matsumoto, Keisuke*; Hoshiyama, Takuya*; Oishi, Daisuke*; Akahama, Hiroshi*; Yoshii, Kenji; Kano, Jun*; Hanasaki, Noriaki*; Kambe, Takashi*; Ikeda, Naoshi*; Mori, Shigeo*

no journal, , 

We have investigated the physical properties of YbFeMnO, a derivative system of the electronic ferroelectric RFeO (R: rare earths). Electron diffraction measurements showed taht long-range charge ordering of the Fe-3d charges was observed at room temperature for x=0; this ordering is the origin of ferroelectricity. The x=0.1 oxide showed diffuse scattering patterns at room temperature, instead of the charge-ordered pattern. Thus, 5% Mn substitution can collapse the long-range charge ordering. We will also present the correlation between the magnetic/dielectric properties and the crystal structure.

An Experimental study on grease fluidity in a ball bearing using neutron imaging technology

Sakai, Kazumi*; Ogata, Rui*; Yamada, Shuhei*; Kimura, Nobuharu*; Matsumoto, Yoshihiro*; Kurita, Keisuke

no journal, , 

Rolling element bearings with grease lubrication are widely used for axis rotations in motors. Unlike liquid lubricants, the fluidity of semisolid greases in bearings plays an important role in bearing performances. The fluidity is often described as channeling and churning states. The states are well known, however, cannot be seen from outside bearings. Therefore, visualizations of greases in bearings are beneficial to understand the grease fluidity, however, methods for non-destructive observations of the inside of bearings are limited. The neutron imaging technology was applied for non-destructive observation of the grease fluidity inside a ball bearing in this study. The technology is based on a characteristic that neutron passes through heavy elements and interacts to light elements. In other words, neutron can identify lubricants with light elements inside the bearing with heavy elements.