Nagano, Tetsushi; Naganawa, Hirochika; Suzuki, Hideya; Toshimitsu, Masaaki*; Mitamura, Hisayoshi*; Yanase, Nobuyuki*; Grambow, B.
Analytical Sciences, 34(9), p.1099 - 1102, 2018/09
A previously reported emulsion flow (EF) extraction system does not include a device for refining used solvent. Therefore, the processing of large quantities of wastewater by using the EF extractor alone could lead to the accumulation of wastewater components into the solvent and diminished extraction performance. In the present study, we have developed a solvent-washing-type EF system, which is equipped with a unit for washing used solvent to prevent accumulation, and successfully applied it for treating uranium-containing wastewater.
Nagasu, Ryosuke*; Tanabe, Daijiro*; Yokotsuka, Satoshi*; Kumazawa, Noriyuki*; Ajiki, Takaya*; Aizawa, Yusuke*; Naganawa, Hirochika; Nagano, Tetsushi; Yanase, Nobuyuki*; Mitamura, Hisayoshi*; et al.
Kankyo Joka Gijutsu, 17(2), p.58 - 61, 2018/03
A new technology to suppress cesium migration from forests has been developed collaboratively by Ibaraki University, Kumagai-gumi Co., Ltd. and its group company, Technos, and JAEA. The new technology utilizes polyelectrolytes (polymers with electric charges) and clay minerals to control Cs migration with the aid of natural forces such as rainfall and rainwater runoff. In Imitate-mura, Fukushima, verification tests of the new technology have been performed and its effect on controlling Cs migration from forests to grass farm adjoining the forests has been proven.
Yamashita, Yuji*; Yanase, Nobuyuki; Nagano, Tetsushi; Mitamura, Hisayoshi; Naganawa, Hirochika
Journal of Radioanalytical and Nuclear Chemistry, 305(2), p.583 - 587, 2015/08
We propose a method for the decontamination and waste volume reduction of cesium-contaminated soil. The soils were solidified with an interpolyelectrolyte complex solution and classified into several size fractions by wet sieving. -ray spectrometry of these fractions showed that the distribution ratio of the activity concentration of coarse soil particles decreased, whereas that of soil particles under 0.075 mm increased relative to reference samples. Results show that the fine soil particles, on which radioactive cesium accumulates, were removed from the surface of the coarse soil particles during, and remained in the washing water.
Kanda, Nobuhiro; Daiten, Masaki; Endo, Yuji; Yoshida, Hideaki; Mita, Yutaka; Naganawa, Hirochika; Nagano, Tetsushi; Yanase, Nobuyuki
JAEA-Technology 2015-007, 43 Pages, 2015/03
The centrifuge which has the subtlety information concerning the nuclear nonproliferation used for uranium enrichment technical development exists in the uranium enrichment facilities of Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency. This centrifugal is performing separation processing of the radioactive material adhering to the surface of parts by wet decontamination of ultrasonic cleaning by dilute sulfuric acid and water, etc. By removing the uranium contained in waste fluid, generated sludge reduces activity concentration. And the possibility of reduction of sludge processing is examined. For this reason, from the 2007 fiscal year, Nuclear Science and Engineering Directorate and cooperation are aimed at, and development of the extraction separation technology of the "uranium" by the emulsion flow method is furthered. The test equipment using the developed emulsion flow method was tested. And dilute sulfuric acid and water were used for the examination as actual waste fluid. The result checked whether the various performances in Basic test carried out in Nuclear Science and Engineering Directorate would be obtained.
Nagano, Tetsushi; Mitamura, Hisayoshi; Yanase, Nobuyuki; Naganawa, Hirochika; Yasuda, Kenichiro; Yamaguchi, Hiroaki*
Hoshasei Busshitsu No Kyuchaku, Josen Oyobi Taihoshasen Gjutsu Ni Okeru Zairyo, Seko, Sokutei No Shin Gijutsu, p.400 - 408, 2014/11
A method for monitoring radioactive cesium concentration in water using a cesium adsorption disk and a GM survey meter has been developed to ascertain whether the water quality meets standards on radiological contaminants in water. This method was successfully applied to monitoring of decontaminated water of an outdoor school swimming pool in Date City after Fukushima Daiichi Nuclear Power Plant accident.
Nagano, Tetsushi; Mitamura, Hisayoshi; Yamashita, Yuji; Yanase, Nobuyuki; Suzuki, Hideya; Naganawa, Hirochika
Solvent Extraction Research and Development, Japan, 21(1), p.111 - 117, 2014/00
Simulated electroless nickel plating liquid wastes have been processed by using an emulsion flow extractor of a counter current type with a special focus on influences of dilution of the liquid wastes on the extraction performance. The emulsion flow extractor provides an efficient liquid-liquid extraction by sending solutions without additional stirring or shaking. A solvent used in the present study was Shellsol D70 solution containing LIX84-I as an extractant for nickel and PC88A as an accelerating agent. As a result, it was found that increasing degree of dilution with water resulted in improvement of nickel extractabilities obtained from the emulsion flow experiments with a maximum value of 96% as well as those obtained from batch experiments. Droplet sizes at the lower and the upper sides of emulsion phases, estimated by using high-speed microscope, were 214 36 m and 415 110 m, respectively.
Nagano, Tetsushi; Yanase, Nobuyuki; Naganawa, Hirochika; Mitamura, Hisayoshi; Hanzawa, Yukiko; Mita, Yutaka; Kanda, Nobuhiro; Ohashi, Yusuke; Endo, Yuji; Matsubara, Tatsuo
Nihon Genshiryoku Gakkai Wabun Rombunshi, 12(4), p.277 - 285, 2013/12
no abstracts in English
Saegusa, Jun; Kurikami, Hiroshi; Yasuda, Ryo; Kurihara, Kazuo; Arai, Shigeki; Kuroki, Ryota; Matsuhashi, Shimpei; Ozawa, Takashi; Goto, Hiroaki; Takano, Takao; et al.
Health Physics, 104(3), p.243 - 250, 2013/03
After the Nuclear accident on March 2011, water discharge from many outdoor swimming pools in the Fukushima prefecture was suspended out of concern that radiocesium in the pool water would flow into farmlands. We have reviewed the existing flocculation method for decontaminating pool water and established a practical decontamination method by demonstrating the process at several pools in the Fukushima prefecture.
Nagano, Tetsushi; Mitamura, Hisayoshi; Yanase, Nobuyuki; Naganawa, Hirochika; Yasuda, Kenichiro; Yoshida, Zenko; Yamaguchi, Hiroaki*
Nihon Hoshasen Anzen Kanri Gakkai-Shi, 11(2), p.139 - 145, 2012/11
An on-site monitoring method for radioactive cesium concentration in water using a cesium adsorption disk and a GM survey meter has been developed to rapidly and easily ascertain whether the water quality meets standards on radiological contaminants in water. In this method, both dissolved and suspended forms of radioactive cesium are collected on the cesium adsorption disk by means of filtration of a water sample. Beta counting rate of the disk is converted into radioactivity using a conservative calibration factor obtained here. The present on-site method was applied to monitoring of decontaminated water of an outdoor school swimming pool in Date city after Fukushima Dai-ichi Nuclear Power Plant accident.
Ito, Kenichi*; Miyahara, Hidetaka*; Ujiie, Toru*; Takeshima, Toshikatsu*; Yokoyama, Shingo*; Nakata, Kotaro*; Nagano, Tetsushi; Sato, Tsutomu*; Hatta, Tamao*; Yamada, Hirohisa*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 11(4), p.255 - 271, 2012/04
no abstracts in English
Naganawa, Hirochika; Kumazawa, Noriyuki*; Saito, Hiroshi*; Yanase, Nobuyuki; Mitamura, Hisayoshi; Nagano, Tetsushi; Kashima, Kaoru*; Fukuda, Tatsuya*; Yoshida, Zenko; Tanaka, Shunichi*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 10(4), p.227 - 234, 2011/12
no abstracts in English
Yanase, Nobuyuki; Naganawa, Hirochika; Nagano, Tetsushi; Noro, Junji*
Analytical Sciences, 27(3), p.325 - 330, 2011/03Licensable Patent Information Database Patent publication (In Japanese)
A single current "emulsion flow" liquid-liquid extraction apparatus has a head having a number of holes from which micrometer-sized droplets of an aqueous phase spout into an organic phase to mix the two liquid phases. For practical use, however, it is a fatal problem that particulate components in the aqueous phase plug the holes. In the present study, we have succeeded to solve the problem by applying a counter current type emulsion flow apparatus where micrometer-sized droplets of the organic phase are generated.
Naganawa, Hirochika; Suzuki, Hideya*; Yanase, Nobuyuki; Nagano, Tetsushi; Noro, Junji*
Analytical Sciences, 27(3), p.321 - 324, 2011/03
In order to monitor a radioactive nuclide of strontium-90 in seawater around nuclear facilities, a solvent extraction method for collecting Sr(II) in seawater was examined. A reversed-micellar extraction system containing an anionic surfactant AOT and a molecular extractant TODGA in n-hexane was chosen for the extraction of Sr(II) from model solutions of seawater containing 0.5 M NaCl (1 M = 1 mol dm), 0.05 M MgCl, and/or 0.01 M CaCl. The combination of AOT forming reversed micelles and TODGA coordinating with Sr(II) as an organic ligand (extractant) was found to be efficient for the extraction of Sr(II) from the model solutions. The mechanism of the reversed-micellar extraction system was also discussed in the present study.
Nagano, Tetsushi; Yanase, Nobuyuki; Hanzawa, Yukiko; Takada, Morio*; Mitamura, Hisayoshi; Sato, Tsutomu*; Naganawa, Hirochika
Water, Air, and Soil Pollution, 216(1-4), p.153 - 166, 2011/03
Schwertmannite is a poorly-crystalline ferric sulphate mineral that secondarily forms in acid mine drainages (AMD) as a result of the oxidative weathering of pyrite (FeS2), and is known to work as a naturally-occurring scavenger of some toxic elements in AMD-contaminated streams due to its high fixation potentials. In this study, to examine the feasibility of using schwertmannite in water purification technique, we evaluate the affinity of some selected elements to schwertmannite using two parameters: (1) conventional apparent solid-liquid partition coefficients between schwertmannite and stream waters, and (2) newly introduced parameters that correspond to ratios of ions fixed by schwertmannite to those existing as dissolved phases. As a result, both of the two parameters revealed that schwertmannite has high fixation potential for fluvial transport of various toxic anions such as V, Cr, As, Mo and Sb in AMD-contaminated streams, and that it could be used for purification of waters contaminated with these toxic anions.
Yanase, Nobuyuki; Naganawa, Hirochika; Nagano, Tetsushi; Noro, Junji*
Analytical Sciences, 27(2), p.171 - 174, 2011/02Licensable Patent Information Database Patent publication (In Japanese)
A simple and low-cost apparatus for continuous and efficient liquid-liquid extraction, which does not need continual mechanical forces (stirring, shaking, etc.) other than solution sending, has newly been developed. This apparatus is composed of a column part where an emulsion state fluid flow (emulsion flow) is generated by spouting micrometer-sized droplets of an aqueous phase into an organic phase and a phase separating part where the emulsion flow is destabilized by means of a sudden decrease in its flow rate. In the present study, the performance of an emulsion flow apparatus in the extraction of Yb(III) and U(VI) from aqueous HNO solutions into isooctane containing D2EHPA was evaluated. The mixing efficiency of the emulsion flow apparatus was found to be comparable with that of a popular liquid-liquid extractor, mixer-settler. Moreover, the emulsion flow apparatus proved to have an overwhelming advantage in terms of phase-separating ability.
Mitamura, Hisayoshi; Naganawa, Hirochika; Nagano, Tetsushi; Yanase, Nobuyuki; Hanzawa, Yukiko; Shimojo, Kojiro; Matsubara, Tatsuo; Mita, Yutaka; Taki, Tomihiro; Murata, Masato
JAEA-Research 2008-113, 27 Pages, 2009/03
An effective mass processing equipment using solvent extraction method, named "emulsion flow extractor," is the most promising apparatus for removal and recovery of uranium from liquid waste originated from decontamination of uranium-contaminated fluoride waste in the uranium conversion test facility and of used gas centrifuges in the uranium enrichment facility at Ningyo-toge environmental engineering center. Prior to application of the emulsion flow extractor for actual uranium-containing liquid waste, properties of some phosphorous extractants for extraction and separation of uranium and constituents from simulated liquid wastes were examined through batch tests. These preliminary tests revealed that D2EHPA would be a promising candidate for extractant used for treatment of the actual uranium-containing liquid wastes, and that the extractants with a surfactant like AOT would not be useful.
Nakayama, Shinichi; Iida, Yoshihisa; Nagano, Tetsushi; Akimoto, Toshiyuki
Journal of Nuclear Science and Technology, 40(4), p.227 - 237, 2003/04
Leaching behavior of synthetic bituminized waste form was studied to inquire data for performance assessment of the geologic disposal. Laboratory-scale leaching tests were performed. The bituminized samples were contacted with an alkaline solution representing cement-contacting groundwater, with a saline solution simulating seawater for a possible repository construction at the coastal area, and with deionized water as reference. The release of soluble components, Na and Cs, was enhanced by the swelling, and considered to be diffusion controlled in the swelled layers of the specimens. The release of insoluble components such as Ba and Np was solubility-limited in addition to control by the progression of leaching. Neptunium, a redox-sensitive element, showed a distinct difference in release reflecting the difference between the anoxic and atmospheric conditions. The concentrations of Pu were below the detection limit ( mol/L) under all of the leaching conditions in this study.
Nagano, Tetsushi; Yanase, Nobuyuki; Tsuzuki, Katsunori; Nagao, Seiya*
Environment International, 28(7), p.649 - 658, 2003/01
In order to investigate the role of suspended particulate matter (SPM) in fluvial discharge of trace and major elements in the Kuji River, Japan, the SPM concentrations in the river water and chemical compositions of SPM were analyzed together with the dissolved form concentrations. The SPM concentrations increased by 2 or 3 orders of magnitude with the water discharge, and also had seasonal variations. The suspended species have the key role in transport of some trace and major elements in some fluvial environments and hence should be taken into account in estimating the total discharge through the river waters.
Nagano, Tetsushi; Isobe, Hiroshi*; Nakashima, Satoru*; Ashizaki, Midori*
Applied Spectroscopy, 56(5), p.651 - 657, 2002/05
no abstracts in English
Nagano, Tetsushi; Nakayama, Shinichi
Genshiryoku Bakkuendo Kenkyu, 8(1), p.81 - 88, 2001/09
Japan Atomic Energy Research Institute has studied to predict the long-term migration of radionuclides in geosphere in terms of radioactive waste disposal. The research activity was introduced to junior high and high school students at a seminar of the Mineralogical Society of Japan. The content of the lecture was summarized.