Iwamoto, Hiroki; Nakano, Keita; Meigo, Shinichiro; Satoh, Daiki; Iwamoto, Yosuke; Sugihara, Kenta*; Nishio, Katsuhisa; Ishi, Yoshihiro*; Uesugi, Tomonori*; Kuriyama, Yasutoshi*; et al.
EPJ Web of Conferences, 284, p.01023_1 - 01023_4, 2023/05
For accurate prediction of neutronic characteristics for accelerator-driven systems (ADS) and a source term of spallation neutrons for reactor physics experiments for the ADS at Kyoto University Critical Assembly (KUCA), we have launched an experimental program to measure nuclear data on ADS using the Fixed Field Alternating Gradient (FFAG) accelerator at Kyoto University. As part of this program, the proton-induced double-differential thick-target neutron-yields (TTNYs) and cross-sections (DDXs) for iron, lead, and bismuth have been measured with the time-of-flight (TOF) method. For each measurement, the target was installed in a vacuum chamber on the beamline and bombarded with 107-MeV proton beams accelerated from the FFAG accelerator. Neutrons produced from the targets were detected with stacked, small-sized neutron detectors for several angles from the incident beam direction. The TOF spectra were obtained from the detected signals and the FFAG kicker magnet's logic signals, where gamma-ray events were eliminated by pulse shape discrimination. Finally, the TTNYs and DDXs were obtained from the TOF spectra by relativistic kinematics. The measured TTNYs and DDXs were compared with calculations by the Monte Carlo transport code PHITS with its default physics model of INCL version 4.6 combined with GEM and those with the JENDL-4.0/HE nuclear data library.
Watanabe, Yukinobu*; Sadamatsu, Hiroki*; Araki, Shohei; Nakano, Keita; Kawase, Shoichiro*; Kin, Tadahiro*; Iwamoto, Yosuke; Satoh, Daiki; Hagiwara, Masayuki*; Yashima, Hiroshi*; et al.
EPJ Web of Conferences, 284, p.01041_1 - 01041_4, 2023/05
Intensive fast neutron sources using deuteron accelerators have been proposed for the study of medical RI production, radiation damage for fusion reactor materials, nuclear transmutation of radioactive waste, and so on. Neutron production data from various materials bombarded by deuterons are required for the design of such neutron sources. In the present work, we have conducted a systematic measurement of double-differential neutron production cross sections (DDXs) for a wide atomic number range of targets (Li, Be, C, Al, Cu, Nb, In, Ta, and Au) at an incident energy of 200 MeV in the Research Center for Nuclear Physics (RCNP), Osaka University. A deuteron beam accelerated to 200 MeV was transported to the neutron experimental hall and focused on a thin target foil. Emitted neutrons from the target were detected by two different-size EJ301 liquid organic scintillators located at two distances of 7 m and 20 m, respectively. The neutron DDXs were measured at six angles from 0 to 25). The neutron energy was determined by a conventional time-of-flight (TOF) method. The measured DDXs were compared with theoretical model calculations by the DEUteron-induced Reaction Analysis Code System (DEURACS) and PHITS. The result indicated that the DEURACS calculation provides better agreement with the measured DDXs than the PHITS calculation.
Iwamoto, Hiroki; Nakano, Keita; Meigo, Shinichiro; Satoh, Daiki; Iwamoto, Yosuke; Sugihara, Kenta; Nishio, Katsuhisa; Ishi, Yoshihiro*; Uesugi, Tomonori*; Kuriyama, Yasutoshi*; et al.
Journal of Nuclear Science and Technology, 60(4), p.435 - 449, 2023/04
Double-differential thick target neutron yields (TTNYs) for Fe, Pb, and Bi targets induced by 107-MeV protons were measured using the fixed-field alternating gradient accelerator at Kyoto University for research and development of accelerator-driven systems (ADSs) and fundamental ADS reactor physics research at the Kyoto University Critical Assembly (KUCA). Note that TTNYs were obtained with the time-of-flight method using a neutron detector system comprising eight neutron detectors; each detector has a small NE213 liquid organic scintillator and photomultiplier tube. The TTNYs obtained were compared with calculation results using Monte Carlo-based spallation models (i.e., INCL4.6/GEM, Bertini/GEM, JQMD/GEM, and JQMD/SMM/GEM) and the evaluated high-energy nuclear data library, i.e., JENDL-4.0/HE, implemented in the particle and heavy iontransport code system (PHITS). All models, including JENDL-4.0/HE, failed to predict high-energy peaks at a detector angle of 5. Comparing the energy- and angle-integrated spallation neutron yields at energies of 20 MeV estimated using the measured TTNYs and the PHITS indicated that INCL4.6/GEM would be suitable for the Monte Carlo transport simulation of ADS reactor physics experiments at the KUCA.
Iwamoto, Osamu; Iwamoto, Nobuyuki; Kunieda, Satoshi; Minato, Futoshi; Nakayama, Shinsuke; Abe, Yutaka*; Tsubakihara, Kosuke*; Okumura, Shin*; Ishizuka, Chikako*; Yoshida, Tadashi*; et al.
Journal of Nuclear Science and Technology, 60(1), p.1 - 60, 2023/01
Kabumoto, Hiroshi; Matsuda, Makoto; Nakamura, Masahiko; Ishizaki, Nobuhiro; Kutsukake, Kenichi; Otokawa, Yoshinori; Asozu, Takuhiro; Matsui, Yutaka; Nakagawa, Sohei; Abe, Shinichi
Proceedings of 19th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1109 - 1113, 2023/01
no abstracts in English
Shibata, Motoki*; Nakanishi, Yohei*; Abe, Jun*; Arima, Hiroshi*; Iwase, Hiroki*; Shibayama, Mitsuhiro*; Motokawa, Ryuhei; Kumada, Takayuki; Takata, Shinichi; Yamamoto, Katsuhiro*; et al.
Polymer Journal, 6 Pages, 2023/00
Iwamoto, Hiroki; Nakano, Keita; Meigo, Shinichiro; Satoh, Daiki; Iwamoto, Yosuke; Ishi, Yoshihiro*; Uesugi, Tomonori*; Kuriyama, Yasutoshi*; Yashima, Hiroshi*; Nishio, Katsuhisa; et al.
JAEA-Conf 2022-001, p.129 - 133, 2022/11
For accurate prediction of neutronic characteristics for accelerator-driven systems (ADS) and a source term of spallation neutrons for reactor physics experiments for the ADS at Kyoto University Critical Assembly (KUCA), we have launched an experimental program to measure nuclear data on ADS using the Fixed Field Alternating Gradient (FFAG) accelerator at Kyoto University. As part of this program, the proton-induced double-differential thick-target neutron-yields (TTNYs) and cross-sections (DDXs) for iron have been measured with the time-of-flight (TOF) method. For each measurement, the target was installed in a vacuum chamber on the beamline and bombarded with 107-MeV proton beams accelerated from the FFAG accelerator. Neutrons produced from the targets were detected with stacked, small-sized neutron detectors composed of the NE213 liquid organic scintillators and photomultiplier tubes, which were connected to a multi-channel digitizer mounted with a field-programmable gate array (FPGA), for several angles from the incident beam direction. The TOF spectra were obtained from the detected signals and the FFAG kicker magnet's logic signals, where gamma-ray events were eliminated by pulse shape discrimination applying the gate integration method to the FPGA. Finally, the TTNYs and DDXs were obtained from the TOF spectra by relativistic kinematics.
Sogabe, Tomochika*; Nakagawa, Hiroshi; Yamada, Takeshi*; Koseki, Shigenobu*; Kawai, Kiyoshi*
Biophysical Journal, 121(20), p.3874 - 3882, 2022/10
The purpose of this study was to clarify the glass transition behavior of bacteria () as a function of water activity (). Mechanical relaxation was investigated at 298 K, and the mechanical ( at which mechanical glass transition occurs at 298 K) was determined to be 0.667. Temperature-dependency of mean square displacement was investigated by inelastic neutron scattering. From the linear fitting, two dynamical transition temperatures (low and high-) were determined. There was a minor effect of on the low- except for the anhydrous sample. The high- largely increased with the decrease in . The dynamical determined by high- (0.688) was slightly higher than the mechanical because of the difference in the measurement time-scale. The high- was converted to the glass transition temperature (), and anhydrous was estimated to be 411 K. Bacterial inactive-active transition was discussed according to the glass transition behavior.
Otosaka, Shigeyoshi*; Jeon, H.*; Hou, Y.*; Watanabe, Takahiro; Aze, Takahiro*; Miyairi, Yosuke*; Yokoyama, Yusuke*; Ogawa, Hiroshi*
Nuclear Instruments and Methods in Physics Research B, 527, p.1 - 6, 2022/09
The measurement the radiocarbon of dissolved organic matter (DOC) in seawater can provide information about a timescale of the dynamics of dissolved organic matter as well as about its sources in the ocean. Due to the low DOC concentration in seawater, in spite of the development of accelerator mass spectrometry, a relatively large volume of seawater (1 L) is required for that analysis. In addition, complicated processing such as UV irradiation that emits high heat is required. In this study, we have developed a safer and easier method to analyze DOC in seawater than the conventional method. A particularly significant change was the adoption of a low-pressure mercury lamp in the decomposition system, which enabled direct decomposition of organic matter at lower temperatures. We also propose a method to quantitatively evaluate the accuracy of this system by analyzing simulated seawater consists of a soluble reference material of organic matter and sodium chloride. This method is expected to be applied not only to carbon isotope ratio analysis but also to analysis of trace elements and isotopes of various dissolved organic substances.
Nasu, Mitsunori*; Yanai, Hiroshi*; Hirayama, Naoki*; Adachi, Hironori*; Kakizawa, Yu*; Shirase, Yuto*; Nishiyama, Hiromichi*; Kawamoto, Teppei*; Inukai, Junji*; Shinohara, Takenao; et al.
Journal of Power Sources, 530, p.231251_1 - 231251_11, 2022/05
Asakura, Kazuki; Shimomura, Yusuke; Donomae, Yasushi; Abe, Kazuyuki; Kitamura, Ryoichi; Miyakoshi, Hiroyuki; Takamatsu, Misao; Sakamoto, Naoki; Isozaki, Ryosuke; Onishi, Takashi; et al.
JAEA-Review 2021-020, 42 Pages, 2021/10
The disposal of radioactive waste from the research facility need to calculate from the radioactivity concentration that based on variously nuclear fuels and materials. In Japan Atomic Energy Agency Oarai Research and Development Institute, the study on considering disposal is being advanced among the facilities which generate radioactive waste as well as the facilities which process radioactive waste. This report summarizes a study result in FY2020 about the evaluation method to determine the radioactivity concentration in radioactive waste on Oarai Research and Development Institute.
Matsuda, Makoto; Tayama, Hidekazu; Ishizaki, Nobuhiro; Kabumoto, Hiroshi; Nakamura, Masahiko; Kutsukake, Kenichi; Otokawa, Yoshinori; Asozu, Takuhiro; Matsui, Yutaka; Abe, Shinichi
Proceedings of 18th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.394 - 398, 2021/10
no abstracts in English
Inagawa, Jun; Kitatsuji, Yoshihiro; Otobe, Haruyoshi; Nakada, Masami; Takano, Masahide; Akie, Hiroshi; Shimizu, Osamu; Komuro, Michiyasu; Oura, Hirofumi*; Nagai, Isao*; et al.
JAEA-Technology 2021-001, 144 Pages, 2021/08
Plutonium Research Building No.1 (Pu1) was qualified as a facility to decommission, and preparatory operations for decommission were worked by the research groups users and the facility managers of Pu1. The operation of transportation of whole nuclear materials in Pu1 to Back-end Cycle Key Element Research Facility (BECKY) completed at Dec. 2020. In the operation included evaluation of criticality safety for changing permission of the license for use nuclear fuel materials in BECKY, cask of the transportation, the registration request of the cask at the institute, the test transportation, formulation of plan for whole nuclear materials transportation, and the main transportation. This report circumstantially shows all of those process to help prospective decommission.
Abe, Fumiaki; Kawabata, Kuniaki; Suzuki, Kenta; Yashiro, Hiroshi
2021 IEEE/SICE International Symposium on System Integration (SII 2021), Vol.2, p.835 - 836, 2021/07
Sato, Tomonori; Hata, Kuniki; Kaji, Yoshiyuki; Ueno, Fumiyoshi; Inoue, Hiroyuki*; Taguchi, Mitsumasa*; Seito, Hajime*; Tada, Eiji*; Abe, Hiroshi*; Akiyama, Eiji*; et al.
JAEA-Review 2021-001, 123 Pages, 2021/06
In the implement of the decommissioning of Fukushima Daiichi Nuclear Power Station (1F), there are many problems to be solved. Specially, the mitigation of the aging degradation by the corrosion of the structural materials is important to implement the decommissioning safely and continuously. However, there are limited data for the environmental factors of corrosion in 1F, and the condition of 1F is continuously changing. So, the literature data for the water radiolysis and the corrosion under irradiation are listed as the database of corrosion under irradiation in this report. And the new obtained radiolysis and corrosion data, which have not been reported in the literature and will be required in the decommissioning of 1F, are reported.
Sanada, Yukihisa; Kurikami, Hiroshi; Funaki, Hironori; Yoshimura, Kazuya; Abe, Tomohisa; Ishida, Mutsushi*; Tanimori, Soichiro*; Sato, Rina
Nihon Genshiryoku Gakkai Wabun Rombunshi, 20(2), p.62 - 73, 2021/06
Japanese government starts to consider radiation protection in the "specific reconstruction reproduction base area" of which evacuation order will be lifted by 2023. It is essential to grab the present situations of radiation contamination and evaluate exposure dose in the area to realize the plan. Many surveys have evaluated the distributions of air dose rate and exposure dose has been estimated based on the results since the Fukushima Daiichi Nuclear Power Plant accident. Nevertheless, more detailed information on exposure is needed for the areas because its radiation level is relatively high. That is also to help make prudent evaluation plan. This study aimed to evaluate the detailed contamination situation there and estimate exposure dose with considering areal circumstances. Investigations were carried out for (1) airborne survey of air dose rate using an unmanned helicopter (2) evaluation of airborne radiocesium and (3) estimation of external/internal effective doses for typical activity patterns assumed.
Suzuki, Kenta; Abe, Fumiaki; Yashiro, Hiroshi; Kawabata, Kuniaki
JAEA-Testing 2020-009, 254 Pages, 2021/03
This report is the user manual of HAIROWorldPlugin for Choreonoid. Our motivation is to develop a robot simulator based on Choreonoid for technological development to contribute the decommissioning work at the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Company Holdings, Inc. Choreonoid is an open source simulator which calculates the behavior of robots. The plugin is an extended function of Choreonoid which provides simulated behavior and phenomenon related to decommissioning tasks utilizing remotely operated robots. In particular, we developed additional functionalities for simulating the behavior of an underwater swimming robot, the behavior of an unmanned aerial vehicle robot, low visibility camera images, network communication failures, etc., and packaged these in the plugin. This report describes the installation of the plugin to Choreonoid on Ubuntu18.04-LTS and parameter settings of the plugin by presenting snapshots of operation windows.
Sakakibara, Hiroshi; Aoki, Nobuhiro; Muto, Masahiro; Otabe, Jun; Takahashi, Kenji*; Fujita, Naoyuki*; Hiyama, Kazuhiko*; Suzuki, Hirokazu*; Kamogawa, Toshiyuki*; Yokosuka, Toru*; et al.
JAEA-Technology 2020-020, 73 Pages, 2021/03
The decommissioning is currently in progress at the prototype fast breeder reactor Monju. Fuel assemblies will be taken out of its core for the first step of the great task. Fuel assemblies stand on their own spike plugged into a socket on the core support plate and support with adjacent assemblies through their housing pads each other, resulting in steady core structure. For this reason, some substitutive assemblies are necessary for the purpose of discharging the fuel assemblies of the core. Monju side commissioned, therefore, Plutonium Fuel Development Center to manufacture the substitutive assemblies and the Center accepted it. This report gives descriptions of design, manufacture, and shipment in regard to the substitutive assemblies.
Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.
Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03
Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.
Watanabe, Hiroshi*; Watanabe, Yutaka*; Hirayama, Yoshikazu*; Andreyev, A. N.; Hashimoto, Takashi*; Kondev, F. G.*; Lane, G. J.*; Litvinov, Yu. A.*; Liu, J. J.*; Miyatake, Hiroari*; et al.
Physics Letters B, 814, p.136088_1 - 136088_6, 2021/03