Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Umezawa, Katsuhiro; Morimoto, Yasuyuki; Nakayama, Takuya; Nakagiri, Toshio
Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 6 Pages, 2019/05
In December 2016, the Ningyo-toge Environmental Engineering Center of Japan Atomic Energy Agency (JAEA Ningyo-toge) announced new concept of "Uranium and Environmental Research Platform". As part of the concept, uranium waste engineering research are now undergoing. The objective of the research is to establish the processing technology for safely and reasonable disposal of uranium waste. In particular, estimation of the amount of uranium and harmful substances and development of technologies to reduce their concentration in the waste to the permissive level for the disposal in shallow ground disposal are needed. We are now developing the technologies to reduce the concentration of uranium and harmful substances shown below. (1) Survey on uranium inventory. Uranium waste is now stored in 10-odd thousands of 200 L drums. We are surveying amount and chemical form of uranium in the drums. (2) Development of decontamination technology of metal and concrete waste. We are investigating decontamination methods for metals and concrete contaminated with uranium. (3) Development of technologies to remove, detoxify and fix the harmful substances. We are surveying the types and amounts of harmful substances in waste. In addition, we are investigating the method to remove, detoxify, and fix harmful substances. (4) Measurement technology of uranium radioactivity. We are investigating and examining ways to improve the quantitative accuracy of measurement and shorten the measurement time. (5) Development of uranium removal technology from sludge. We are investigating new processing method to remove uranium from sludge which is applicable for several kind of sludge. The results of these technological developments and environmental research will be reflected to "small-scale field test" and "disposal demonstration test" which are planned for demonstration of the uranium waste disposal technology.
Nakayama, Takuya; Yagi, Naoto; Sato, Kazuhiko; Hinoda, Shingo; Nakagiri, Toshio; Morimoto, Yasuyuki; Umezawa, Katsuhiro; Sugitsue, Noritake
JAEA-Review 2018-005, 163 Pages, 2018/03
JAEA-Review-2018-005.pdf:72.95MB
The Ningyo-toge Environmental Engineering Center of JAEA has been working together with local communities for more than 60 years. Through our R&D projects on from uranium exploration to uranium enrichment as a part of the nuclear fuel cycle (i.e., front-end), we have accumulated experiences in the fields of management of uranium related technology. Taking advantage of such our potential, we will start new R&D program on "Research on Uranium and the Environment". In December 2016 we announced our new concept of the "Uranium and Environmental Research Platform" as a framework aimed at contributing to regional and international society through R&D programs (environmental research and uranium waste engineering research) that are needed to steadily carry out decommissioning of uranium handling facilities.
Sawaguchi, Takuma; Takai, Shizuka; Umezawa, Katsuhiro; Takeda, Seiji; Okada, Takashi
Nihon Genshiryoku Gakkai-Shi ATOMO
, 59(8), p.445 - 447, 2017/08
no abstracts in English
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.
Umezawa, Katsuhiro; Nakayama, Shinichi
Konsoryu, 26(4), p.418 - 425, 2012/12
JAEA has been conducting diversified activities on the environmental remediation for Fukushima after the Great East Japan Earthquake, including radiation monitoring, decontamination demonstration, public communications, and related R&D. The decontamination pilot project was carried out in the off-limit and scheduled evacuation zones, where existing and/or improved clean-up techniques were tested their applicability and efficiency, waste storage was established, and how to secure workers' safety for radiation was investigated. Related R&D has also been continued, such as computer simulation for decontamination planning, and aircraft radiation monitoring.
Umezawa, Katsuhiro; Takeuchi, Yoshio; Kato, Mitsugu
no journal, ,
no abstracts in English
Kawase, Keiichi; Kato, Mitsugu; Iijima, Kazuki; Mori, Hideharu; Umezawa, Katsuhiro; Tanabe, Tsutomu
no journal, ,
no abstracts in English
Sudo, Tomoyuki; Ishikawa, Hiroyasu; Uesaka, Takahiro*; Sonoda, Takashi; Ishikawa, Nobuyuki*; Niizato, Tadafumi; Mikake, Shinichiro; Aoki, Isao; Ishizaki, Nobuhiro; Imamura, Hiroaki; et al.
no journal, ,
JAEA is working the decontamination activity for the environmental remediation of Fukushima. In this activity, I support the decontamination activity for local governments to devise a decontamination plan and actually decontaminate. In this report, 1 introduce the technical knowhow for the decontamination activity of a house.
Suyama, Yasuhiro*; Nishikawa, Takeshi*; Tokizawa, Takayuki; Kato, Mitsugu; Kurikami, Hiroshi; Umezawa, Katsuhiro
no journal, ,
no abstracts in English
Sugitsue, Noritake; Yokoyama, Kaoru; Ohara, Yoshiyuki; Osugi, Takeshi; Okoshi, Minoru; Umezawa, Katsuhiro
no journal, ,
Some waste radioactive Cs concentration is low, is processed by incineration existing facilities. After gasification in the incineration process, radioactive cesium is attached to the fly ash and bottom ash due to aggregation. Fly ash adhering radioactive Cs is collected with high efficiency such as electrostatic precipitators and bag filters. Radioactive Cs, which is re-emitted from the Exhaust stack is a very small amount. We describe the construction of simulation code for analyzing these mechanisms.
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.
Umezawa, Katsuhiro; Haginoya, Masashi; Kato, Mitsugu; Asazuma, Shinichiro
no journal, ,
no abstracts in English
Umezawa, Katsuhiro; Haginoya, Masashi; Kato, Mitsugu; Asazuma, Shinichiro
no journal, ,
no abstracts in English
Sawaguchi, Takuma; Takai, Shizuka; Umezawa, Katsuhiro; Takeda, Seiji; Okada, Takashi
no journal, ,
no abstracts in English
Horie, Hiroki*; Akiyama, Yoko*; Mishima, Fumihito*; Nishijima, Shigehiro*; Mitsui, Seiichiro; Umezawa, Katsuhiro; Kato, Mitsugu; Okada, Takashi; Sekiyama, Tomio*
no journal, ,
A technique for volume reduction and recycle of cesium contaminated soil in combination with wet classification and high gradient magnetic separation was investigated. The magnetic separation can fractionate the fine soil particles (silt and clay) into high-dose and low-dose soil. This method utilizes the phenomenon that paramagnetic 2:1 clay strongly adsorbs cesium whereas diamagnetic 1:1 clay has low adsorption ability of cesium. One of the main issues in this technique is that the soil components are aggregated by organic matters, which prevents 2:1 type clay minerals from selective separation. In this study, pretreatment of the soil by K
CO
solution was conducted, prior to the magnetic separation, in order to disperse aggregates. As a result, further selective separation for 2:1 type clay minerals by the pretreatment was confirmed.
Nishimoto, Yuki*; Horie, Hiroki*; Akiyama, Yoko*; Nishijima, Shigehiro*; Mitsui, Seiichiro; Umezawa, Katsuhiro; Kato, Mitsugu; Okada, Takashi; Sekiyama, Tomio*
no journal, ,
By the accident of Fukushima Daiichi Nuclear Power Plant, a large amount of soil was contaminated by radioactive cesium. We developed a new physical treatment method using magnetic separation that can separate high-dose 2:1 type clay minerals from contaminated soil selectively. However, there is an issue that it is difficult to capture 2:1 type clay minerals efficiently, because clay minerals form aggregations with soil organic matter. Our previous study indicated that aggregates can be dispersed effectively by treatment of organic matter with KCO solution. The purpose of this study is to assess the effect of the organic matter treatment on efficiency improvement of magnetic separation for 2:1 type clay minerals. The result showed that the possibility of effective treatment method for the soil rich in organic matter like agricultural soil by combination of the pretreatment with KCO solution and magnetic separation.
