Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Mori, Airi; Ishizaki, Azusa; Futemma, Akira; Tanabe, Tsutomu; Wada, Takao; Kato, Mitsugu; Munakata, Masahiro
Hoken Butsuri (Internet), 54(1), p.45 - 54, 2019/04
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.
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.
Yanagisawa, Tsutomu; Tanabe, Hiromi
Nihon Genshiryoku Gakkai-Shi ATOMO
, 49(7), p.499 - 504, 2007/07
The first story of this serial handles the early days of FBRs. The progress of nuclear physics in the 1930's led to the development of the FBR. Fast neutrons as for fission generator, plutonium for nuclear fuels and liquid metal as for the coolant were selected to obtain a higher breeding ratio. Based on the experience of the Clementine Reactor, the EBR-I went critical in August 1951. Moreover, they succeeded in electricity generation in December 1951 and later confirmed breeding. The results of EBR-I project are thought to demonstrate the controllability of the fast neutron, the utility of liquid metals, and the reality of breeding.
Sakakibara, Tetsuro; Tsutomu, Tanabe,; Takahashi, Kuniaki; Akutsu, Shigeru; Kojima, Hiroshi; Sakashita, Akira*; Kuroda, Kazuhiko*
Proceedings of International Waste Management Symposium 2005 (WM 2005), 0 Pages, 2005/00
Focusing on the cover layer materials (as the Radon Barrier Materials), which could have the effect to restrain the radon from scattering into the air and the effect of the radiation shielding, we produced the radon barrier materials with crude bentonite on an experimental basis, using the rotary type comprehensive unit for grinding and mixing, through which we carried out the evaluation of the characteristics thereof.
; ; Koakutsu, Masayuki; ; Miyamoto, Yasuaki; Takeda, Seiichiro
Saikuru Kiko Giho, (16), 37- Pages, 2002/00
None
; ; ; Takeda, Seiichiro
JNC TN8420 2001-008, 134 Pages, 2001/07
This investigation was conducted as a part of planning the low-level radioactive waste management program (LLW management program). The aim of this investigation was contributed to compile the radioactive waste database of JNC's LLW management program. All nuclear facilities of the Tokai works and Ningyo-toge Environmental Engineering Center were investigated in this work. The wastes generated by the decomissioning of each nuclear facility were classified into radioactive waste and others (exempt waste and non-radioactive waste), and the amount of the wastes was estimated. The estimated amounts of radioactive wastes generated by decomissioning of the nuclear facilities are as follows. (1)Tokai works. The amount of waste generated by decommissioning of nuclear facilities of the Tokai works is about 1,079,100 ton. The amount of radioactive waste is about 15,400 ton. The amount of exempt waste and non-radioactive waste is about 1,063,700 ton. (2)Ningyo-toge Environmental Engineering Center. The amount of waste generated by decommissioning of nuclear facilities of Ningyo-toge Environmental Engineering Center is about 112,500 ton. The amount of radioactive waste is about 7,800 ton. The amount of exempt waste and non-radioactive waste is about 104,700 ton.
Tanabe, Tsutomu; Wada, Takao; Iijima, Kazuki
no journal, ,
no abstracts in English
Kawase, Keiichi; Kato, Mitsugu; Iijima, Kazuki; Mori, Hideharu; Umezawa, Katsuhiro; Tanabe, Tsutomu
no journal, ,
no abstracts in English
Tanabe, Tsutomu
no journal, ,
no abstracts in English
Umezawa, Katsuhiro*; Kato, Mitsugu; Tanabe, Tsutomu; Wada, Takao
no journal, ,
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.
Mori, Airi; Ishizaki, Azusa; Tanabe, Tsutomu; Wada, Takao; Kato, Mitsugu; Munakata, Masahiro
no journal, ,
no abstracts in English
Takeyasu, Masanori; Takeishi, Minoru; Yoda, Tomoyuki; Saegusa, Jun; Koizumi, Jin*; Tanabe, Tsutomu
no journal, ,
The measurement of air dose rate surrounding roads is important for developing plans for reducing radiation exposure with road traffic. The measurements were performed by vehicle-borne or man-borne surveys until now. However, air dose rate resulting from radioactivity on roads in mainly measured for former survey, and much man-power for long time measurement was necessary for the latter. In this study, we focused on the field of view for measurement being different with a difference of the detector setting height above the ground, and carried out the vehicle-borne survey along roads in evacuation zone in Fukushima prefecture with two detectors mounted at different heights. By this measurement, air dose rate surrounding the roads is discriminated. From the results, the radioactivity contamination trend was clarified, and are valuable for developing decontamination plan around the road.
Sr to environmental samples with online solid phase extraction/ICP-MSHagiwara, Hiroki; Yanagisawa, Kayo*; Kuwata, Haruka*; Tanabe, Tsutomu; Uezu, Yasuhiro
no journal, ,
no abstracts in English
