Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
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
Times Cited Count：43 Percentile：96.93(Astronomy & Astrophysics)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.
(Al,Ga)
O
scintillator Compton camera mounted on an unmanned helicopterShikaze, Yoshiaki; Nishizawa, Yukiyasu; Sanada, Yukihisa; Torii, Tatsuo; Jiang, J.*; Shimazoe, Kenji*; Takahashi, Hiroyuki*; Yoshino, Masao*; Ito, Shigeki*; Endo, Takanori*; et al.
Journal of Nuclear Science and Technology, 53(12), p.1907 - 1918, 2016/12
Times Cited Count：37 Percentile：96.48(Nuclear Science & Technology)The Compton camera was improved for use with the unmanned helicopter. Increase of the scintillator array from 4
4 to 88 and expanse of the distance between the two layers contributed to the improvements of detection efficiency and angular resolution, respectively. Measurements were performed over the riverbed of the Ukedo river of Namie town in Fukushima Prefecture. By programming of flight path and speed, the areas of 65 m 60 m and 65 m 180 m were measured during about 20 and 30 minutes, respectively. By the analysis the air dose rate maps at 1 m height were obtained precisely with the angular resolution corresponding to the position resolution of about 10 m from 10 m height. Hovering flights were executed over the hot spot areas for 10-20 minutes at 5-20 m height. By using the reconstruction software the 
-ray images including the hot spots were obtained with the angular resolution same as that evaluated in the laboratory (about 10).
Kobayashi, Shinji*; Niimi, Katsuyuki*; Tsuji, Masakuni*; Yamada, Toshiko*; Aoyagi, Yoshiaki; Sato, Toshinori; Mikake, Shinichiro; Osawa, Hideaki
JAEA-Technology 2015-039, 170 Pages, 2016/02
JAEA-Technology-2015-039.pdf:37.73MB
The researches on engineering technology in the Mizunami Underground Research Laboratory (MIU) plan consists of (1) development of design and construction planning technologies, (2) development of construction technology, (3) development of countermeasure technology, (4) development of technology for security, and (5) development of technologies regarding restoration or reversal and mitigating of the excavation effect. To develop design and construction planning technologies, and countermeasure technology, the analysis of measured data during earthquake and seismic movement characteristics at deep underground, and the examination of grouting method were carried out. For the characteristics of earthquake ground motion, measurement data obtained by seismometers installed in the Mizunami Underground Laboratory were analyzed, and the comprehensive assessment of the relationship between the measurement data and the geological condition at each depth was performed. As for "Study on grouting method at deep underground ", post grouting was carried out and evaluated based on the Construction plan in FY2013. Furthermore, target of the future R&D was proposed.
Hiraiwa, Kenichi*; Hirai, Kazuhide*; Sano, Tadashi*; Osawa, Hideaki; Sato, Toshinori; Aoyagi, Yoshiaki; Fujita, Tomoo; Aoyagi, Kazuhei; Inagaki, Daisuke*
JAEA-Technology 2015-033, 50 Pages, 2015/11
JAEA-Technology-2015-033.pdf:12.6MB
Japan Atomic Energy Agency (hereinafter referred to as JAEA) has been conducted a geoscientific research and development project at the Mizunami Underground Research Laboratory and the Horonobe Underground Research Laboratory in order to construct scientific and technological basis for geological disposal. As a collaborative research between JAEA and Tokyo Sokki Kenkyujo Co., Ltd. (hereinafter referred to as TML), we focused on the fiber-optic crack detection sensor developed by TML as a method to detect cracks in the support system that may affect the stability of rock cavern during the operation. To verify long-term safety performance of the sensor for decades, "Evaluation test of long-term durability of fiber-optic crack detection sensor and the support system" at the Mizunami Underground Research Laboratory and "Performance evaluation test of fiber-optic crack detection sensor for in-situ crack detection" at the Horonobe Underground Laboratory Research Laboratory were conducted. As the result, we understand that fiber-optic crack detection sensor is applicable measurement method to promptly detect the cracks in the support system.
pellets for Mo-99 production, 2Nishikata, Kaori; Ishida, Takuya; Yonekawa, Minoru; Kato, Yoshiaki; Kurosawa, Makoto; Kimura, Akihiro; Matsui, Yoshinori; Tsuchiya, Kunihiko; Sano, Tadafumi*; Fujihara, Yasuyuki*; et al.
KURRI Progress Report 2014, P. 109, 2015/07
As one of effective applications of the Japan Materials Testing Reactor (JMTR), JAEA has a plan to produce 
Mo by (n,) method ((n,)Mo production), a parent nuclide of 
Tc. In this study, preliminary irradiation test was carried out with the high-density molybdenum trioxide (MoO) pellets in the hydraulic conveyer (HYD) of the Kyoto University Research Reactor (KUR) and the Tc solution extracted from Mo was evaluated. After the irradiation test of the high-density MoO pellets in the KUR, Tc was extracted from the Mo solution and the recovery rate of Tc achieved the target values. The Tc solution also got the value that satisfied the standard value for Tc radiopharmaceutical products by the solvent extraction method.
Somekawa, Hidetoshi*; Yamaguchi, Masatake; Osawa, Yoshiaki*; Singh, A.*; Itakura, Mitsuhiro; Tsuru, Tomohito; Mukai, Toshiji*
Philosophical Magazine, 95(8), p.869 - 885, 2015/02
Times Cited Count：23 Percentile：70.58(Materials Science, Multidisciplinary)no abstracts in English
pellets for Mo-99 productionNishikata, Kaori; Ishida, Takuya; Yonekawa, Minoru; Kato, Yoshiaki; Kurosawa, Makoto; Kimura, Akihiro; Matsui, Yoshinori; Tsuchiya, Kunihiko; Sano, Tadafumi*; Fujihara, Yasuyuki*; et al.
KURRI Progress Report 2013, P. 242, 2014/10
As one of effective applications of the Japan Materials Testing Reactor (JMTR), JAEA has a plan to produce Mo-99 (Mo) by (n,) method ((n,)Mo production), a parent nuclide of Tc. In this study, preliminary irradiation tests were carried out with the high-density MoO pellets in the KUR and the Mo production amount was evaluated between the calculation results and measurement results.
Kurosawa, Ryohei; Sakai, Akihiro; Nakata, Hisakazu; Amazawa, Hiroya; Sakamoto, Yoshiaki
JAEA-Technology 2014-013, 89 Pages, 2014/06
JAEA-Technology-2014-013.pdf:23.93MB
In the safety assessment for the trench disposal facilities, outflow of radioactive material to the environment is assumed to be due to the percolating rain water into the waste layer, because the waste layer is established above the groundwater level. Therefore, in dose assessment of trench type disposal facilities, it is important to evaluate how the structure of the upper cover soil layers affects the suppressed amount of water infiltration to the waste layer due to rainfall.
Kurosawa, Makoto; Kato, Yoshiaki; Yonekawa, Minoru; Taguchi, Taketoshi
UTNL-R-0486, p.9_1 - 9_11, 2014/03
It has been irradiated in the concrete cell, the microscope lead cell, the lead cell for materials examinations and the iron cell and, in the JMTR Hot Laboratory Facilities, examines it after the irradiation such as fuel and nuclear reactor structure materials. I install a monitoring board for a concrete cell, a microscope lead cell, a lead cell for materials examinations and iron cells in the control room I watch concentration such as the minus number pressure in these each cell, the air absorption dose rate in the cell, the cover door opening and shutting indication and to control it. As for these monitoring boards, about 30 through 40 or more passed after an in-service start, and high aging decided to update it in consideration of the driving of approximately 20 years after JMTR re-operation because trouble by becoming it and outbreak of the malfunction were concerned about.
Sakai, Akihiro; Kurosawa, Ryohei; Hara, Hironori*; Nakata, Hisakazu; Amazawa, Hiroya; Arikawa, Masanobu*; Sakamoto, Yoshiaki
JAEA-Technology 2013-039, 228 Pages, 2014/02
JAEA-Technology-2013-039.pdf:24.05MB
The sensitivity analysis of doses in terms of the environmental conditions was performed by statistical method in order to make the technical basis for the siting criteria of near surface disposal facility for low level radioactive waste generated from research, industrial and medical facilities. Doses calculated at all assumed pathways in more than 97.5% of calculation cases were able to be reduced below the target dose after control period (0.01 mSv/y) by means of equipping the disposal facility with additional engineered barriers. As a result, we concluded it was possible to safely and rationally design disposal facilities in most of the environmental parameters related to safety assessment. Another sensitivity analysis was done in order to discuss the area of disposal site. Dose at the site boundary were able to be reduce below the target dose during operation (0.05 mSv/y) whenever the distances from these facilities to the site boundary were more than 120 m, respectively.
Nakata, Hisakazu; Amazawa, Hiroya; Sakai, Akihiro; Kurosawa, Ryohei; Kanno, Naohiro*; Kashima, Takahiro*; Sakamoto, Yoshiaki
JAEA-Technology 2013-036, 47 Pages, 2014/02
JAEA-Technology-2013-036.pdf:5.27MB
The Low-level Radioactive Waste Disposal Project Center will construct near surface disposal facilities. The disposal facilities consist of concrete pit type for low-level radioactive wastes and trench type for very low level radioactive wastes. As for the trench type disposal facility, two kinds of facility designs are on projects -one for normal trench type disposal facilities and the other for trench type disposal facilities with geomembrane liners that could prevent from causing environmental effects of non radioactive toxic materials. This study examined mechanical strength and permeability properties to assess the durability on the basis of an indoor accelerated exposure experiment targeting the liner materials presumed to avail the conceptual design so far. Its results will be used for the basic and detailed design henceforth by confirming the empirical degradation characteristic with the progress of the exposure time.
MoTaguchi, Taketoshi; Yonekawa, Minoru; Kato, Yoshiaki; Kurosawa, Makoto; Nishikata, Kaori; Ishida, Takuya; Kawamata, Kazuo
UTNL-R-0483, p.10_5_1 - 10_5_13, 2013/03
JMTR focus on the activation method. By carrying out the preliminary tests using irradiation facilities existing, and verification tests using the irradiation facility that has developed in the cutting-edge research and development strategic strengthening business, as irradiation tests towards the production of Mo, we have been conducting research and development that can contribute to supply about 25% for Mo demand in Japan and the stable supply of radiopharmaceutical. This report describes a summary of the status of the preliminary tests for the production of Mo: Maintenance of test equipment in the facility in JMTR Hot Laboratory in preparation for research and development for the production of Mo in JMTR and using MoO pellet irradiated at Kyoto University Research Reactor Institute (KUR).
Amazawa, Hiroya; Sakai, Akihiro; Nakata, Hisakazu; Hara, Hironori; Kurosawa, Ryohei; Yamamoto, Masayuki*; Kawata, Yosuke*; Sakamoto, Yoshiaki
JAEA-Technology 2012-031, 338 Pages, 2012/10
JAEA-Technology-2012-031.pdf:19.43MB
JAEA is responsible for siting a proper location to establish new disposal facilities with siting criterion and procedure, in consideration of transparency and impartial for the siting process, based on Plan Concerning the Disposal Business Execution. As a part of the study to draw up siting criterion and procedure, Sensitivity analysis of the disposal facilities from the viewpoint of dose evaluation and cost estimation under various siting condition will be carried out. Therefore, Conceptual design of disposal facilities as a reference case is necessary. The basic condition of the design conforms to the property, quantity, radioactivity of waste packages, technical standards and likely siting condition. This report summarizes the results of the reasonable design of our disposal facilities and the layout of the place of activity where the disposal facilities and associated facilities to be installed.
Osawa, Hideaki; Ota, Kunio; Hama, Katsuhiro; Sawada, Atsushi; Takeuchi, Shinji; Amano, Kenji; Saegusa, Hiromitsu; Matsuoka, Toshiyuki; Miyamoto, Tetsuo; Toyoda, Gakuji; et al.
JAEA-Research 2008-085, 742 Pages, 2008/11
JAEA-Research-2008-085-1.pdf:26.22MBJAEA-Research-2008-085-2.pdf:16.64MBJAEA-Research-2008-085-3.pdf:28.27MB
This report shows the results the project for the establishment of comprehensive site characterization technology, entrusted from Natural Resources and Energy Agency, Ministry of Economy, Trade and Industry Natural Resources and Energy Agency in 2007.
Shinohara, Nobuo; Inoue, Yoji; Uchikoshi, Takako*; Oda, Tetsuzo*; Kumata, Masahiro; Kurosawa, Yoshiaki; Hirota, Naoki*; Hokida, Takanori; Nakahara, Yoshinori*; Yamamoto, Yoichi
Dai-25-Kai Kaku Busshitsu Kanri Gakkai Nihon Shibu Nenji Taikai Rombunshu, p.51 - 58, 2005/00
The Japan Atomic Energy Research Institute (JAERI) conducts researches and developments related to Comprehensive Nuclear-Test-Ban Treaty (CTBT) on the basis of Japan's pragmatic and progressive efforts toward peaceful use of atomic energy and non-proliferation with the goal of realizing a peaceful and safe world free from nuclear weapons. The Treaty aims for the establishment of a global verification regime comprising an International Monitoring System (IMS) and the JAERI has engaged in the following activities: construction and operation of the radionuclide monitoring stations at Okinawa (RN37) and Takasaki (RN38) and the certified radionuclide laboratory at Tokai (RL11) as specified in Annex 1 of CTBT Protocol, and preparation of the National Data Center at Tokai (JAERI NDC). Research activities of JAERI related to the CTBT verification regime are presented in the paper. The subjects of this presentation are (1) an overview of the CTBT verification regime, (2) construction and operation of RN37, RN38 and RL11, and (3) preparation of the JAERI NDC for radionuclide data.
Hirota, Naoki*; Hokida, Takanori; Inoue, Yoji; Kumata, Masahiro; Kurosawa, Yoshiaki; Miyamoto, Yutaka; Nakahara, Yoshinori; Oda, Tetsuzo; Shinohara, Nobuo; Uchikoshi, Takako*; et al.
JAERI-Review 2003-021, 68 Pages, 2003/08
JAERI-Review-2003-021.pdf:9.73MB
This report describes research activities of the R & D Group for Non-Proliferation Technology related to the Comprehensive Nuclear-Test-Ban Treaty (CTBT) verification regime. The main subjects of this report are (1) an overview of the CTBT verification regime, (2) preparation of the National Data Center for radionuclide data, (3) construction and operation of the radionuclide monitoring stations at Takasaki and Okinawa and the certified rarionuclide laboratory at Tokai in Japan. We have participated in an intercomparison test internationally organized for the certified laboratories and the test results are given here. Scientific application of the CTBT-related technologies to environmental researches is also depicted.
Ashikagaya, Yoshinobu; Yoshino, Toshiaki; Yasu, Katsuji; Kurosawa, Yoshiaki; Sawa, Kazuhiro
JAERI-Tech 2002-094, 80 Pages, 2002/12
JAERI-Tech-2002-094.pdf:12.8MB
no abstracts in English
Ishii, Toshimitsu; Ooka, Norikazu; Saito, Junichi; Kobayashi, Shunichi; Takahashi, Kunihiro; Tsukada, Takashi; Iwai, Takashi; Kurosawa, Yoshiaki; Hoshiya, Taiji; Tsuji, Hirokazu
Proceedings of International Symposium on Case Histories on Integrity and Failures in Industry (CHIFI), p.227 - 236, 1999/00
no abstracts in English
Yoshimura, Kimitaka*; Okazaki, Koji*; Osato, Kazumi*; Nakashima, Satoshi*; Osawa, Kenji*; Yabuuchi, Satoshi; Yamanaka, Yoshiaki; Shigeta, Naotaka
no journal, ,
no abstracts in English
Yoshimura, Kimitaka*; Okazaki, Koji*; Osato, Kazumi*; Osawa, Kenji*; Yamaoka, Masanobu*; Nakashima, Satoshi*; Shigeta, Naotaka; Yabuuchi, Satoshi; Yamanaka, Yoshiaki*
no journal, ,
no abstracts in English
