Weyl-Kondo semimetal behavior in the chiral structure phase of CeRhSn

Iwasa, Kazuaki*; Suyama, Kazuya*; Kawamura, Seiko; Nakajima, Kenji; Raymond, S.*; Steffens, P.*; Yamada, Akira*; Matsuda, Tatsuma*; Aoki, Yuji*; Kawasaki, Ikuto; et al.

Physical Review Materials (Internet), 7(1), p.014201_1 - 014201_11, 2023/01

https://doi.org/10.1103/PhysRevMaterials.7.014201

Flexible and tough superelastic Co-Cr alloys for biomedical applications

Odaira, Takumi*; Xu, S.*; Hirata, Kenji*; Xu, X.*; Omori, Toshihiro*; Ueki, Kosuke*; Ueda, Kyosuke*; Narushima, Takayuki*; Nagasako, Makoto*; Harjo, S.; et al.

Advanced Materials, 34(27), p.2202305_1 - 2202305_11, 2022/07

https://doi.org/10.1002/adma.202202305

Hard X-ray photoelectron spectroscopy study of Pt/YFeO

Kobata, Masaaki; Yoshii, Kenji; Fukuda, Tatsuo; Kawasaki, Ikuto; Okane, Tetsuo; Yamagami, Hiroshi; Yaita, Tsuyoshi; Harii, Kazuya; Ieda, Junichi; Okayasu, Satoru; et al.

JPS Conference Proceedings (Internet), 30, p.011192_1 - 011192_6, 2020/03

https://doi.org/10.7566/JPSCP.30.011192

High energy X-ray photoelectron spectroscopy (HAXPES) measurements were carried out for the Spin Seebeck system Pt/YFeO(YIG). This system was found to show anomalous Hall effect, possible due to the formation of intermetallic compounds between Fe and Pt. To reveal this possibility, we have measured the Fe 1s photoelectron peaks by using HAXPES. It was found that the Fe ions consist of Fe in YIG and metallic Fe. The formation of the metallic state is consistent with the proposed origin of the anomalous Hall effect. Other spectra such as Pt 4f will be presented at the conference.

Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex, 2; Neutron scattering instruments

Nakajima, Kenji; Kawakita, Yukinobu; Ito, Shinichi*; Abe, Jun*; Aizawa, Kazuya; Aoki, Hiroyuki; Endo, Hitoshi*; Fujita, Masaki*; Funakoshi, Kenichi*; Gong, W.*; et al.

Quantum Beam Science (Internet), 1(3), p.9_1 - 9_59, 2017/12

https://doi.org/10.3390/qubs1030009

The neutron instruments suite, installed at the spallation neutron source of the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC), is reviewed. MLF has 23 neutron beam ports and 21 instruments are in operation for user programs or are under commissioning. A unique and challenging instrumental suite in MLF has been realized via combination of a high-performance neutron source, optimized for neutron scattering, and unique instruments using cutting-edge technologies. All instruments are/will serve in world-leading investigations in a broad range of fields, from fundamental physics to industrial applications. In this review, overviews, characteristic features, and typical applications of the individual instruments are mentioned.

Long-term outlook of energy demand and supply in Japan; Estimation of energy demand and supply for "Nuclear Energy Vision 2100" of JAEA

Tatematsu, Kenji; Kawasaki, Hirotsugu; Nemoto, Masahiro; Murakami, Masakazu

JAEA-Research 2009-007, 46 Pages, 2009/06

JAEA-Research-2009-007.pdf:3.96MB

In this study, we showed an energy demand and supply scenario toward the year 2100 in Japan, which underlies JAEA's "Nuclear Energy Vision 2100" published in October 2008. This energy demand and supply scenario aims at the coexistence of the reduction of the carbon dioxide emission and the energy security through reduction of the fossil fuel usage, positive electrification and the nuclear energy usage. We reduce the ratio of the fossil fuel in the primary energy supply to about 1/3 and extend the share of renewable and nuclear energy to 70% from current 15%. As a result, the carbon dioxide emission is reduced to current 10%, and it developed that the half was the contribution of the nuclear energy.

Construction status of a general control system for the Materials and Life Science Experimental Facility (MLF) at J-PARC

Sakai, Kenji; Oi, Motoki; Kai, Tetsuya; Kinoshita, Hidetaka; Kawasaki, Susumu; Watanabe, Akihiko; Kaminaga, Masanori; Futakawa, Masatoshi

Nuclear Instruments and Methods in Physics Research A, 600(1), p.75 - 77, 2009/02

https://doi.org/10.1016/j.nima.2008.11.122

In order to operate all equipment of the Materials and Life Science Experimental Facility (MLF) safely and efficiently, the MLF general control system (MLF-GCS) is designed to have several subsystems such as the facility control system centering on the control of the targets, interlock systems for protecting personnel, machine and the neutron target, and so on. Although it is an independent system, the MLF-GCS should also be as a part of the control system of the whole J-PARC operated from the central control room (CCR). The construction of MLF-GCS has been almost finished, and its performance test is in progress to check and adjust remote operations and integral interlocks from the control room of MLF. This paper gives an overview of the MLF-GCS and reports its construction status.

Research for the life-extension of the wide-range monitoring neutron detectors of HTTR (Joint research)

Saito, Kenji; Sekita, Kenji; Kawasaki, Kozo; Yamamoto, Kazuhiko*; Matsuura, Makoto*

JAEA-Technology 2007-059, 36 Pages, 2007/11

JAEA-Technology-2007-059.pdf:26.24MB

The Wide-Range Monitoring neutron detectors of HTTR are used under 450 C in normal operation and 550 C in the accidents. When the WRM detectors are used under the high temperature for a long time, characteristics of the detector might be degraded, because of the decrease of the nitrogen concentration in the ionization gas caused by adsorbtion of nitrogen into the electrode material. Consequently, the nitrogen gas adsorption test was carried out to clarify the quantity of absorbed nitrogen gas in electrode material under the high temperature. Then, the performance evaluation test of the prototype detector was carried out, and it was confirmed that degradation of the prototype detector characteristics didn't arise under the high temperature anvironment. This report describes the results of consideration about the life-extension of WRM detectors. As a result, it was confirmed that the WRM detectors are usable for 5 years under 450 C in normal operation and 550 C in the accidents.

Operating experiences since rise-to-power test in High Temperature Engineering Test Reactor (HTTR)

Tochio, Daisuke; Watanabe, Shuji; Motegi, Toshihiro; Kawano, Shuichi; Kameyama, Yasuhiko; Sekita, Kenji; Kawasaki, Kozo

JAEA-Technology 2007-014, 62 Pages, 2007/03

JAEA-Technology-2007-014.pdf:9.74MB

The rise-to-power test of the High Temperature Engineering Test Reactor (HTTR) was begun in April 2000. The reactor thermal power of 30 MW, which is the maximum thermal power of the HTTR, and the reactor outlet coolant temperature of 850C in normal operation was achieved in middle of December 2001. After that reactor thermal power of 30 MW a reactor outlet coolant temperature of 950C was achieved in the final rise-to-power test at April 2004. After receiving the operation permit, the safety demonstration tests were conducted to demonstrate inherent safety features of the HTGRs. This paper summarizes the HTTR operating experiences for five years since rise-to-power test that were catalogued into three categories, (1) Operating experience pertaining to new gas cooled reactor design, (2) Operating experience for improvement of the performance, (3) Operating experience due to fail of system and components.

Evaluation of prediction accuracy for U Doppler effect measured in FCA LWR simulating cores; Analysis with JENDL-3.3 library and SRAC system (Joint research)

Kawasaki, Kenji*; Ando, Masaki; Okajima, Shigeaki; Fukushima, Masahiro; Nakano, Makoto*; Matsumoto, Hideki*

JAEA-Research 2006-008, 40 Pages, 2006/03

JAEA-Research-2006-008.pdf:3.6MB

Analysis was performed to evaluate prediction accuracy of a neutronics code system for thermal reactor; the SRAC system with the use of the latest nuclear data library JENDL-3.3 for the U Doppler effect measured in the uranium fueled (FCA-XXI-1D2) and MOX fueled (XXII-1 series) cores. The results of the analysis with the diffusion theory showed overestimation by up to +11%. In relatively soft neutron spectra, however, the calculated values agreed with the experimental ones within the experimental errors.

Benchmark analysis of KRITZ-2 critical experiments

Okumura, Keisuke; Kawasaki, Kenji*; Mori, Takamasa

JAERI-Research 2005-018, 64 Pages, 2005/08

JAERI-Research-2005-018.pdf:3.26MB

In the KRITZ-2 critical experiments, criticality and pin power distributions were measured at room temperature and high temperature (about 245 degree C) for three different cores loading slightly enriched UO or MOX fuels. For nuclear data testing, benchmark analysis was carried out with a continuous-energy Monte Carlo code MVP and its four nuclear data libraries based on JENDL-3.2, JENDL-3.3, JEF-2.2 and ENDF/B-VI.8. As a result, fairly good agreements with the experimental data were obtained with any libraries for the pin power distributions. However, the JENDL-3.3 and ENDF/B-VI.8 give under-prediction of criticality and too negative isothermal temperature coefficients for slightly enriched UO cores, while the older nuclear data JENDL-3.2 and JEF-2.2 give rather good agreements with the experimental data. From the detailed study with an infinite unit cell model, it was found that the differences among the libraries are mainly due to the different fission cross section of U-235 in the energy rage below 1.0 eV.