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Shikaze, 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:41 Percentile:96.31(Nuclear Science & Technology)The Compton camera was improved for use with the unmanned helicopter. Increase of the scintillator array from 44 to 8
8 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
).
Nishikata, 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.
Nishikata, 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
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
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
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.
Taguchi, 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 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.
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
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
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
Nakata, Hisakazu; Kurosawa, Ryohei; Sakamoto, Yoshiaki
no journal, ,
In the shallow land disposal system for radioactive waste arising from research, industrial and medical facilities, effect of environmentally hazardous substances must be considered adding to radiation effect on human. Some environmentally hazardous substances will be regulated following to the Waste Management and Public Cleansing Law, however, boron, fluoride and nitric ion are not regulated by the Waste Management and Public Cleansing Law. Therefore, in this study, the limitation of the amount of boron, fluoride and nitric ion in the waste forms were evaluated in concrete pit and trench facilities.
Nishikata, Kaori; Kimura, Akihiro; Kato, Yoshiaki; Kurosawa, Makoto; Ishida, Takuya; Tsuchiya, Kunihiko; Kakei, Sadanori*; Yoshinaga, Hideo*; Niizeki, Tomotake*; Hasegawa, Yoshio*
no journal, ,
no abstracts in English
Taguchi, Taketoshi; Kato, Yoshiaki; Yonekawa, Minoru; Kanazawa, Yoshiharu; Ito, Masayasu; Kurosawa, Makoto; Aoyagi, Tatsuhiko; Tayama, Yoshinobu; Sozawa, Shizuo; Kawamata, Kazuo
no journal, ,
no abstracts in English
Iwahashi, Hiroyuki; Do, V. K.; Furuse, Takahiro; Ota, Yuki; Homma, Shunta; Kurosawa, Kiyoko*; Motoki, Yoshiaki*; Hirosawa, Takashi
no journal, ,
The radiometric determination of beta emitting Pd (half-life of 6.5 million years) requires a multiple-step chemical separation and a time-consuming radioactive measurement. Inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) with recent technological advances in interference removal by two quadrupole mass filters and a collision/reaction cell could be an alternative for highly sensitive analysis of long-lived radionuclides. In this study, we have developed an analytical method for the determination of
Pd in concrete rubble by ICP-MS/MS combined with single-column chromatographic separation. A simplified procedure for the separation of Pd from concrete matrices was developed. The measurement condition was optimized to completely suppress the interference including the isobar
Ag and the sample matrices. The application of the developed method to radioactive concrete rubble is under consideration.
Ota, Yuki; Kurosawa, Kiyoko*; Motoki, Yoshiaki*; Do, V. K.; Furuse, Takahiro
no journal, ,
We have developed an analytical method of I (half-life: 1.57x10
years) and
Cl (half-life: 3.01x10
years) in various radioactive rubbles generated by decommissioning of the Fukushima Daiichi Nuclear Power Plant (1F). A sequential chemical separation procedure has been developed to isolate the nuclides from the sample matrix, followed by the quantification by inductively coupled plasma-mass spectrometry (ICP-MS/MS) and liquid scintillation counting (LSC), respectively.
Kurosawa, Ryohei; Sakai, Akihiro; Nakata, Hisakazu; Amazawa, Hiroya; Sakamoto, Yoshiaki
no journal, ,
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 the effect of facility designs that suppresses the amount of water infiltration to the waste layer due to rainfall. Therefore, using the weather conditions in Japan, and evaluated the penetration water into the upper cover soil in trench type disposal facility other than the surface runoff and evapotranspiration. The evaluation was carried out of the water penetration leading to waste layer by migrating the upper cover soil fitted with a water barrier sheet or low-permeable layer soil layer of in trench type disposal facility. As evaluation result, by the influence of vegetation state of the upper cover soil surface, it was found that the amount of water from about 0.2 times to 0.7 times the precipitation have infiltrated to the upper cover soil. By setting the value corresponding to the clay hydraulic conductivity of low permeability soil layer, penetration amount of water to the waste layer from the top upper cover soil, it has been found that it is possible to reduce the penetration amount of water to the upper cover soil from the rain.
Shikaze, Yoshiaki; Torii, Tatsuo; Shimazoe, Kenji*; Jiang, J.*; Takahashi, Hiroyuki*; Kurosawa, Shunsuke*; Kamada, Kei*; Yoshikawa, Akira*; Yoshino, Masao*; Ito, Shigeki*; et al.
no journal, ,
no abstracts in English