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Journal Articles

Continuous liquid-liquid extraction of uranium from uranium-containing wastewater using an organic phase-refining-type emulsion flow extractor

Nagano, Tetsushi; Naganawa, Hirochika; Suzuki, Hideya; Toshimitsu, Masaaki*; Mitamura, Hisayoshi*; Yanase, Nobuyuki*; Grambow, B.

Analytical Sciences, 34(9), p.1099 - 1102, 2018/09

 Times Cited Count:11 Percentile:62.95(Chemistry, Analytical)

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.

Journal Articles

Recontamination prevention technologies to prevent radioactive cesium from its runoff from not decontaminated forests to living areas

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.

Journal Articles

Decontamination and volume reduction of cesium-contaminated soil by combining soil solidification with interpolyelectrolyte complex and wet classification

Yamashita, Yuji*; Yanase, Nobuyuki; Nagano, Tetsushi; Mitamura, Hisayoshi; Naganawa, Hirochika

Journal of Radioanalytical and Nuclear Chemistry, 305(2), p.583 - 587, 2015/08

 Times Cited Count:4 Percentile:40.75(Chemistry, Analytical)

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. $$gamma$$-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.

JAEA Reports

The Uranium waste fluid processing examination by liquid and liquid extraction method using the emulsion flow method

Kanda, Nobuhiro; Daiten, Masaki; Endo, Yuji; Yoshida, Hideaki; Mita, Yutaka; Naganawa, Hirochika; Nagano, Tetsushi; Yanase, Nobuyuki

JAEA-Technology 2015-007, 43 Pages, 2015/03

JAEA-Technology-2015-007.pdf:5.33MB

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.

Journal Articles

On-site monitoring method of radioactive cesium in water sample using cesium adsorption disk and GM survey meter

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.

Journal Articles

Continuous liquid-liquid extraction of nickel from simulated electroless nickel plating liquid wastes by using a counter current emulsion flow extractor

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 $$pm$$ 36 $$mu$$m and 415 $$pm$$ 110 $$mu$$m, respectively.

Journal Articles

Continuous extraction of uranium from actual uranium-containing liquid wastes using an "emulsion flow" extractor

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

Journal Articles

Decontamination of outdoor school swimming pools in Fukushima after the nuclear accident in March 2011

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

 Times Cited Count:3 Percentile:29.69(Environmental Sciences)

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.

Journal Articles

Method for monitoring radioactive cesium concentration in water using cesium adsorption disk and GM survey meter

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.

Journal Articles

Practical approach to decontamination of radioactive cesium-contaminated matter in agricultural region by improved wet classification and use of geomaterials

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

Journal Articles

Removal of radioactive cesium from surface soils solidified using polyion complex; Rapid communication for decontamination test at Iitate-mura in Fukushima Prefecture

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

Journal Articles

Counter current "emulsion flow" extractor for continuous liquid-liquid extraction from suspended solutions

Yanase, Nobuyuki; Naganawa, Hirochika; Nagano, Tetsushi; Noro, Junji*

Analytical Sciences, 27(3), p.325 - 330, 2011/03

 Times Cited Count:7 Percentile:26.47(Chemistry, Analytical)JP, 2008-253779   Licensable 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.

Journal Articles

Reversed-micellar extraction of strontium(II) from model solutions of seawater

Naganawa, Hirochika; Suzuki, Hideya*; Yanase, Nobuyuki; Nagano, Tetsushi; Noro, Junji*

Analytical Sciences, 27(3), p.321 - 324, 2011/03

 Times Cited Count:7 Percentile:26.47(Chemistry, Analytical)

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$$^{-3}$$), 0.05 M MgCl$$_{2}$$, and/or 0.01 M CaCl$$_{2}$$. 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.

Journal Articles

Evaluation of the affinity of some toxic elements to schwertmannite in natural streams contaminated with acid mine drainage

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

 Times Cited Count:7 Percentile:24.45(Environmental Sciences)

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.

Journal Articles

New apparatus for liquid-liquid extraction, "emulsion flow" extractor

Yanase, Nobuyuki; Naganawa, Hirochika; Nagano, Tetsushi; Noro, Junji*

Analytical Sciences, 27(2), p.171 - 174, 2011/02

 Times Cited Count:12 Percentile:41.96(Chemistry, Analytical)JP, 2007-136496   Licensable 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$$_{3}$$ 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.

JAEA Reports

Extraction and separation of uranium from simulated uranium-containing liquid wastes of Ningyo-toge environmental engineering center

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

JAEA-Research-2008-113.pdf:31.84MB

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.

Journal Articles

Leaching behavior of simulated bituminized radioactive waste form under deep geological conditions

Nakayama, Shinichi; Iida, Yoshihisa; Nagano, Tetsushi; Akimoto, Toshiyuki

Journal of Nuclear Science and Technology, 40(4), p.227 - 237, 2003/04

 Times Cited Count:12 Percentile:61.24(Nuclear Science & Technology)

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 ($$2 times 10^{-10}$$ mol/L) under all of the leaching conditions in this study.

Journal Articles

Particulate and dissolved elemental loads in the Kuji River related to discharge rate

Nagano, Tetsushi; Yanase, Nobuyuki; Tsuzuki, Katsunori; Nagao, Seiya*

Environment International, 28(7), p.649 - 658, 2003/01

 Times Cited Count:27 Percentile:53.13(Environmental Sciences)

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.

Journal Articles

Chraracterization of iron hydroxides in a weathered rock surface by visible microspectroscopy

Nagano, Tetsushi; Isobe, Hiroshi*; Nakashima, Satoru*; Ashizaki, Midori*

Applied Spectroscopy, 56(5), p.651 - 657, 2002/05

 Times Cited Count:8 Percentile:46.34(Instruments & Instrumentation)

no abstracts in English

Journal Articles

Implication for long-term behavior of radionuclides in deep underground on the basis of natural analogue phenomena

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.

90 (Records 1-20 displayed on this page)