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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
JAEA-Review-2021-020.pdf:2.95MB
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.
Mori, Airi; Ishizaki, Azusa; Futemma, Akira; Tanabe, Tsutomu; Wada, Takao; Kato, Mitsugu; Munakata, Masahiro
Hoken Butsuri (Internet), 54(1), p.45 - 54, 2019/04
Horie, Hiroki*; Yukumatsu, Kazuki*; Mishima, Fumihito*; Akiyama, Yoko*; Nishijima, Shigehiro*; Sekiyama, Tomio*; Mitsui, Seiichiro; Kato, Mitsugu
Journal of Physics; Conference Series, 871, p.012102_1 - 012102_7, 2017/07
Times Cited Count：1 Percentile：49.36(Physics, Applied)Mori, Airi; Tanabe, Tsutomu; Wada, Takao; Kato, Mitsugu
JAEA-Technology 2017-006, 38 Pages, 2017/03
JAEA-Technology-2017-006.pdf:2.98MB
Large quantities of radioactive materials were released into the environment as a result of the Fukushima Daiichi Nuclear Power Station accident. Residential areas and forest areas near the power station were contaminated with the radioactive materials. Outside of the houses, schools and the other buildings are being decontaminated by national authority and local government. On the other hand, the materials (such as walls, floors, or windows) which constitute the houses are not decontaminated officially. In order to prepare decontamination methods that can be applied easily, we conducted examinations of decontamination for various materials in houses. Fibrous materials, woods, glasses, concretes, plastics, vinyl chloride materials, metals and synthetic leathers were used in our examinations. These materials were collected from houses in difficult-to-return zone, and were contaminated by radioactive materials released by the accident. Dry methods (suction, wiping, adsorption and peelable coating), wet methods (wiping, brushing, polishing and washing) and physical method (peeling of materials) were used for decontamination. As a result of our examinations, materials with low water permeability, such as glasses, concretes, vinyl chloride materials and metals, were able to be decontaminated efficiently (about 90% reduction) by using wet methods. Materials with high water permeability like woods were relatively well decontaminated by peelable coating (about 60%-70% reduction). In addition to the examination described above, the difference of contamination reduction effect between chemical properties of detergents and the effect of rubbing of peelable coating were also examined. Finally, the most effective method was summarized based on these examinations.
Ishihara, Keisuke; Yokota, Akira; Kanazawa, Shingo; Iketani, Shotaro; Sudo, Tomoyuki; Myodo, Masato; Irie, Hirobumi; Kato, Mitsugu; Iseda, Hirokatsu; Kishimoto, Katsumi; et al.
JAEA-Technology 2016-024, 108 Pages, 2016/12
JAEA-Technology-2016-024.pdf:29.74MB
Radioactive isotope, nuclear fuel material and radiation generators are utilized in research institutes, universities, hospitals, private enterprises, etc. As a result, various low-level radioactive wastes (hereinafter referred to as non-nuclear radioactive wastes) are produced. Disposal site for non-nuclear radioactive wastes have not been settled yet and those wastes are stored in storage facilities of each operator for a long period. The Advanced Volume Reduction Facilities (AVRF) are built to produce waste packages so that they satisfy requirements for shallow underground disposal. In the AVRF, low-level beta-gamma solid radioactive wastes produced in the Nuclear Science Research Institute are mainly treated. To produce waste packages meeting requirements for disposal safely and efficiently, it is necessary to cut large radioactive wastes into pieces of suitable size and segregate those depending on their types of material. This report summarizes activities of pretreatment to dispose of non-nuclear radioactive wastes in the AVRF.
Kato, Mitsugu; Tanabe, Tsutomu; Umezawa, Katsuhiro; Wada, Takao
JAEA-Technology 2016-004, 129 Pages, 2016/03
JAEA-Technology-2016-004.pdf:20.42MB
After the Fukushima-Daiichi Nuclear Power Station accident, widespread contamination by radioactive materials occurred. Thus, decontamination work have been developed because of reducing air dose rate. Of this, in order to examine decontamination effect about gravel which cover sites of houses, communal facilities and cemeteries, and about ballast laid on a track, JAEA examined a decontamination test by physical plural methods. The objective of this testing is to establish rational and high effective decontamination methods to decontaminate each different gravel of materials and the shape, using the equipment which have possibility of the decontamination effect by trituration or blast. From the test results, applicability of the decontamination method depending on a characteristic of the gravel and the decontamination effect (reduction rate) are confirmed. There are various characteristics with the thing said to be gravel. It is confirmed that one decontamination method cannot be applied to all types of gravel. Furthermore, it is confirmed that there is great variability among individual polluted condition in the gravel gathered from the same place. Therefore, it is important to measure the degree of pollution so that a measurement error becomes as little as possible. For example, to measure plural points of the measurement side and keeping the height of measurement constant.
Higuchi, Hidekazu; Osugi, Takeshi; Nakashio, Nobuyuki; Momma, Toshiyuki; Tohei, Toshio; Ishikawa, Joji; Iseda, Hirokatsu; Mitsuda, Motoyuki; Ishihara, Keisuke; Sudo, Tomoyuki; et al.
JAEA-Technology 2007-038, 189 Pages, 2007/07
JAEA-Technology-2007-038-01.pdf:15.13MBJAEA-Technology-2007-038-02.pdf:38.95MBJAEA-Technology-2007-038-03.pdf:48.42MBJAEA-Technology-2007-038-04.pdf:20.53MBJAEA-Technology-2007-038-05.pdf:10.44MB
The Advanced Volume Reduction Facilities (AVRF) is constructed to manufacture the waste packages of radioactive waste for disposal in the Nuclear Science Research Institute of the Japan Atomic Energy Agency. The AVRF is constituted from two facilities. The one is the Waste Size Reduction and Storage Facility (WSRSF) which is for reducing waste size, sorting into each material and storing the waste package. The other is the Waste Volume Reduction Facility (WVRF) which is for manufacturing the waste package by volume reducing treatment and stabilizing treatment. WVRF has an induction melting furnace, a plasma melting furnace, an incinerator, and a super compactor for treatment. In this report, we summarized about the basic concept of constructing AVRF, the constitution of facilities, the specifications of machineries and the state of trial operation until March of 2006.
Nakashio, Nobuyuki; Higuchi, Hidekazu; Momma, Toshiyuki; Kozawa, Kazushige; Tohei, Toshio; Sudo, Tomoyuki; Mitsuda, Motoyuki; Kurosawa, Shigenobu; Hemmi, Ko; Ishikawa, Joji; et al.
Journal of Nuclear Science and Technology, 44(3), p.441 - 447, 2007/03
Times Cited Count：9 Percentile：54.79(Nuclear Science & Technology)The Japan Atomic Energy Agency (JAEA) constructed the Advanced Volume Reduction Facilities (AVRF), in which volume reduction techniques are applied and achieved high volume reduction ratio, homogenization and stabilization by means of melting or super compaction processes for low level solid wastes. It will be able to produce waste packages for final disposal and to reduce the volume of stored wastes by operating the AVRF. The AVRF consist of the Waste Size Reduction and Storage Facilities (WSRSF) and the Waste Volume Reduction Facilities (WVRF); the former have cutting installations for large size wastes and the latter have melting units and a super compactor. Cutting installations in the WSRSF have been operating since July 1999. Radioactive wastes treated so far amount to 750 m
and the volume reduction ratio is from 1.7 to 3.7. The WVRF have been operating with non-radioactive wastes since February 2003 for the training and the homogeneity investigation in the melting processes. The operation of the pretreatment system in the WVRF with radioactive wastes has partly started in FY2005.
Higuchi, Hidekazu; Momma, Toshiyuki; Nakashio, Nobuyuki; Kozawa, Kazushige; Tohei, Toshio; Sudo, Tomoyuki; Mitsuda, Motoyuki; Kurosawa, Shigenobu; Hemmi, Ko; Ishikawa, Joji; et al.
Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 6 Pages, 2005/10
The JAERI constructed the Advanced Volume Reduction Facilities(AVRF). The AVRF consists of the Waste Size Reduction and Storage Facilities(WSRSF) and the Waste Volume Reduction Facilities(WVRF). By operating the AVRF, it will be able to produce waste packages for final disposal and to reduce the amount of the low level solid wastes. Cutting installations for large wastes such as tanks in the WSRSF have been operating since June 1999. The wastes treated so far amount to 600 m and the volume reduction ratio is around 1/3. The waste volume reduction is carried out by a high-compaction process or melting processes in the WVRF. The metal wastes from research reactors are treated by the high-compaction process. The other wastes are treated by the melting processes that enable to estimate radioactivity levels easily by homogenization and get chemical and physical stability. The WVRF have been operating with non-radioactive wastes since February 2003 for the training and the homogeneity investigation in the melting processes. The operation with radioactive wastes will start in FY2005.
Takahashi, Teruhiko; Niinuma, Shinichi; Futagawa, Kazuo; Otsuka, Yoshikazu; Muto, Yasushi; Sakai, Toshiya; Umehara, Takashi; Shimizu, Isamu; Umino, Takaaki; Yamada, Satoshi; et al.
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Umezawa, Katsuhiro; Takeuchi, Yoshio; Kato, Mitsugu
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Kawase, Keiichi; Kato, Mitsugu; Iijima, Kazuki; Mori, Hideharu; Umezawa, Katsuhiro; Tanabe, Tsutomu
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Suyama, Yasuhiro*; Nishikawa, Takeshi*; Tokizawa, Takayuki; Kato, Mitsugu; Kurikami, Hiroshi; Umezawa, Katsuhiro
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Umezawa, Katsuhiro*; Kato, Mitsugu; Tanabe, Tsutomu; Wada, Takao
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We are working on the development of new mobile water monitoring equipment, resulting in a novel all-in-one package - the "Water Monitoring Car". This monitoring car is now in production and scheduled for completion in March, 2014. It is designed for in-situ 
-ray spectrometry for 
Cs and 
Cs quantification in water in Fukushima, Japan. This is especially important for areas where it is difficult to take out samples but radioactivity measurements in water in different environments are required for returning residents. Such environments include storage reservoirs for farming and sources of drinking water to houses from mountain runoff. The equipment now used incorporates a Ge semiconductor detector with a spiral-shaped tube molded around it. Water is pumped from the source of interest via hoses, passed through this tube and then discharged. Incorporated lead shielding around the tube has a thickness of 10 cm. Such optimized shielding and the higher resolution of the Ge detector are expected to result in both a lower MDA and higher accuracy at low radiocesium concentrations.
Mitsui, Seiichiro; Sekiyama, Tomio; Kato, Mitsugu; Asazuma, Shinichiro; Kato, Hiroyasu*; Ueta, Shinzo*
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A huge volume of contaminated soils and wastes has been generated by off-site decontamination works in Fukushima and has been stored at temporary storage sites located near or at decontamination sites. The soils and wastes will be sequentially transferred to the Interim Storage Facility (ISF). According to a relevant law, the soils and wastes will be disposed at a final disposal site outside Fukushima within the next 30 years. The total volume of the contaminated soils which will be stored in the ISF is estimated to be up to 20 million cubic meters, thus reduction of its final disposal volume is vital to minimize various impacts of final disposal. In order to optimize final disposal outside Fukushima, the government will commence research and development on soil treatment techniques and use application of less-contaminated soil. As the one and only institution dedicated to the comprehensive R&D of nuclear energy-related technology in Japan, we will support the government efforts.
Umezawa, Katsuhiro; Haginoya, Masashi; Kato, Mitsugu; Asazuma, Shinichiro
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Umezawa, Katsuhiro; Haginoya, Masashi; Kato, Mitsugu; Asazuma, Shinichiro
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Kato, Mitsugu
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Akiyama, Yoko*; Yukumatsu, Kazuki*; Horie, Hiroki*; Mishima, Fumihito*; Sekiyama, Tomio; Mitsui, Seiichiro; Kato, Mitsugu; Nishijima, Shigehiro*
no journal, ,
A large amount of the contaminated soil has been removed in the process of off-site decontamination works in Fukushima prefecture and will be stored intensively at the interim storage facilities (ISF). According to the amended JESCO Law, the National Government shall take necessary measures for the final disposal outside Fukushima within 30 years from the start of the ISF. In order to optimize final disposal of the contaminated soil outside Fukushima, development of effective treatment techniques is indispensable. In this study, we have been investigating selective separation of paramagnetic 2:1 type clay minerals, which strongly absorb and fix Cs ions, by superconducting magnetic separation on silt/clay suspension as a separation technique. We conducted magnetic separation experiments of contaminated soil in Fukushima utilizing a superconducting magnet based on results of particle trajectory simulation for various particle size.
Mori, Airi; Ishizaki, Azusa; Tanabe, Tsutomu; Wada, Takao; Kato, Mitsugu; Munakata, Masahiro
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no abstracts in English
