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Journal Articles

Determination of humic substances in deep groundwater from sedimentary formations by the carbon concentration-based DAX-8 resin isolation technique

Terashima, Motoki; Endo, Takashi*; Miyakawa, Kazuya

Journal of Nuclear Science and Technology, 57(4), p.380 - 387, 2020/04

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

Journal Articles

Nagasaki sediments reveal that long-term fate of plutonium is controlled by select organic matter moieties

Lin, P.*; Xu, C.*; Kaplan, D. I.*; Chen, H.*; Yeager, C. M.*; Xing, W.*; Sun, L.*; Schwehr, K. A.*; Yamazaki, Hideo*; Kokubu, Yoko; et al.

Science of the Total Environment, 678, p.409 - 418, 2019/08

 Times Cited Count:1 Percentile:74.04(Environmental Sciences)

Nagasaki sediments containing bomb-derived Pu provided a unique opportunity to explore the long term geochemical behavior of Pu. Through a combination of selective extractions and molecular characterization via electrospray ionization Fourier-transform ion cyclotron resonance mass spectrometry, we determined that 55 $$pm$$ 3% of the $$^{239,240}$$Pu was preferentially associated with more persistent organic matter compounds in Nagasaki sediments, particularly those natural organic matter (NOM) stabilized by Fe oxides. Other organic matter compounds served as a secondary sink of these $$^{239,240}$$Pu (31 $$pm$$ 2% on average), and less than 20% of the $$^{239,240}$$Pu was immobilized by inorganic mineral particles. While present long-term disposal and environmental remediation modeling assume that solubility limits and sorption to mineral surfaces control Pu subsurface mobility, our observations suggest that NOM undoubtedly plays an important role in sequestering Pu. Ignoring the role of NOM in controlling Pu fate and transport is not justified in most environmental systems.

Journal Articles

Modeling dynamics of $$^{137}$$Cs in forest surface environments; Application to a contaminated forest site near Fukushima and assessment of potential impacts of soil organic matter interactions

Ota, Masakazu; Nagai, Haruyasu; Koarashi, Jun

Science of the Total Environment, 551-552, p.590 - 604, 2016/05

 Times Cited Count:21 Percentile:21.08(Environmental Sciences)

A model for $$^{137}$$Cs transfer in forest was developed to assess behavior of Fukushima-derived $$^{137}$$Cs. The model simulation well reproduced observed 3 year migration of $$^{137}$$Cs in organic layer and mineral soil. Long-term predictions indicated that more than 90% of the deposited $$^{137}$$Cs remains in the top 5 cm soil till 30 years, suggesting that forest acts as a long-term reservoir of $$^{137}$$Cs with limited loss via groundwater pathway. Impacts of soil organic matter (SOM) on $$^{137}$$Cs dynamics were investigated by modifying parameters of $$^{137}$$Cs turnover. The results showed that SOM-induced reduction of $$^{137}$$Cs adsorption, slower fixation of $$^{137}$$Cs by clay and enhanced mobilization of the fixed $$^{137}$$Cs elevate soil-to-plant transfer of $$^{137}$$Cs by increasing fraction of dissolved $$^{137}$$Cs. A substantial proportion (27% $$sim$$ 73%) of $$^{137}$$Cs in these soils was delivered to horizons deeper than 5 cm decades later. These results suggested that SOM significantly influences behavior of $$^{137}$$Cs over long-term.

Journal Articles

Effect of water and oxygen contents on the decomposition of gaseous trichloroethylene in air under electron beam irradiation

Hakoda, Teruyuki; Hashimoto, Shoji; Kojima, Takuji

Bulletin of the Chemical Society of Japan, 75(10), p.2177 - 2183, 2002/10

 Times Cited Count:7 Percentile:64.41(Chemistry, Multidisciplinary)

no abstracts in English

Journal Articles

Radioactive contamination in the aquatic environment as a result of the Chernobyl nuclear accident

Matsunaga, Takeshi; Nagao, Seiya*

Sui Kankyo Gakkai-Shi, 25(4), p.193 - 197, 2002/04

no abstracts in English

Journal Articles

Form of radionuclides dissolved in river at an accidentally contaminated area

Matsunaga, Takeshi; Nagao, Seiya*; Takeda, Seiji; Ueno, Takashi; Amano, Hikaru

Dai-43-Kai Kankyo Hoshano Chosa Kenkyu Seika Rombun Shorokushu (Heisei-12-Nendo), p.49 - 50, 2002/03

no abstracts in English

Journal Articles

The Real-time gas mass filter system for the analysis of products from trichloroethylene-air mixture during electron beam irradiation

Hakoda, Teruyuki; Arai, Hidehiko; Hashimoto, Shoji

Journal of Chemical Engineering of Japan, 34(10), p.1300 - 1308, 2001/10

 Times Cited Count:2 Percentile:74.16(Engineering, Chemical)

The continuous gas monitoring system using the mass filter (CGM-MS) was developed for the measurement of gaseous substances in air under atmospheric pressure. A capillary tube introduces the gases under atmospheric pressure into a mass filter installed in a vacuum chamber. The CGM-MS detected gaseous substances, such as sulfur dioxide, benzene and chlorobenzene, with detectable sensitivity of 0.7-1 ppmv. The monitoring system was also applied for the analysis of the products formed in electron beam irradiation of trichloroethylene (TCE) and air mixture. Dichloroacetyl chloride, carbonyl chloride (COCl$$_{2}$$), and chlorine (Cl$$_{2}$$) were quantitatively analyzed. Trichloroethylene and the products were oxidized and completely converted into carbon dioxide, Cl$$_{2}$$, and hydrochloric acid at 15 kGy. Carbonyl chloride is dissolved in an alkaline solution to be automatically oxidized into CO$$_{3}^{2-}$$ and Cl$$^{-}$$. The combination of the irradiation and the dissolution of the irradiated gas decreased to 7 from 15 kGy for the complete oxidation of TCE and the products.

Journal Articles

Mechanism of 1,1-dichloroethylene decomposition in humid air under electron beam irradiation

Sun, Y.*; Hakoda, Teruyuki; Chmielewski, A. G.*; Hashimoto, Shoji; Zimek, Z.*; Bulka, S.*; Ostapczuk, A.*; Nichipor, H.*

Radiation Physics and Chemistry, 62(4), p.353 - 360, 2001/10

 Times Cited Count:21 Percentile:17.6(Chemistry, Physical)

no abstracts in English

Journal Articles

Complete oxidation of gaseous trichloroethylene in air by electron beam irradiation

Hakoda, Teruyuki; Hirota, Koichi; Hashimoto, Shoji

Proceedings of 5th International Symposium & Exhibition on Environmental Contamination in Central & Eastern Europe (CD-ROM), 7 Pages, 2001/09

no abstracts in English

Journal Articles

Chain oxidation initiated OH, O($$^{3}$$P) radicals, thermal electrons, and O$$_{3}$$ in electron beam irradiation of 1,2-dichloroethylenes and air mixtures

Hakoda, Teruyuki; Zhang, G.*; Hashimoto, Shoji

Radiation Physics and Chemistry, 62(2-3), p.243 - 252, 2001/09

 Times Cited Count:13 Percentile:30.26(Chemistry, Physical)

no abstracts in English

JAEA Reports

Alkali hydrolysis experiment of organic materials such as cement additives

Fukumoto, Masahiro; Nishikawa, Yoshiaki*

JNC-TN8400 2001-017, 355 Pages, 2001/03

JNC-TN8400-2001-017.pdf:6.27MB

The alkali hydrolysis experiments which seem to be important from the view point of the alteration mechanism using the following seven organic materials was performed as a part of the evaluation of the influence on the disposal of the organic materials contained in the TRU wastes. As a result of the alkali hydrolysis experiments (90$$^{circ}$$C and 91d), each organic materials became those of lower molecular weight. The degradation products were able to be detected in the solution. The organic materials seem to be degraded to the organic matters which were confirmed in this study in a long term of disposal. The degradation products were shown below. Therefore, the evaluation of the influence on the migration of radionuclides by degradation products becomes important in the future. (1)Cement additives of Naphthalenesulfonic acid and Ligninsulfonic acid ($$rightarrow$$ Naphthalenedisulfonic acid etc.) (2)Cement additives of polycarboxylic acid ($$rightarrow$$ Oligomer of distal methoxypoly ethylene glycol.) (3)Ethylenediamine-N,N,N',N'-tetraacetic acid disodium salt ($$rightarrow$$ Acetic acid desorped and cyclized organic matters from EDTA.) (4)Tributyl phosphate ($$rightarrow$$ Dibutyl phthalate, n-butanol) (5)Poly vinyl acetate ($$rightarrow$$ Acetic acid) (6)Nylon66 ($$rightarrow$$ Adipic acid, Hexamethylenediamine) (7)Cured epoxy resin ($$rightarrow$$ Glycerol poly glycidyl ether, Carboxylic acid)

JAEA Reports

Studies on groundwater flow and radionuclide migration at underground environments; Final report of collaboration research between JAERI and AECL

Ogawa, Hiromichi; Nagao, Seiya; Yamaguchi, Tetsuji; Mukai, Masayuki; Munakata, Masahiro; Sakamoto, Yoshiaki; Nakayama, Shinichi; Takeda, Seiji; Kimura, Hideo; Kumata, Masahiro; et al.

JAERI-Research 2000-052, 101 Pages, 2001/01

JAERI-Research-2000-052.pdf:8.27MB

no abstracts in English

JAEA Reports

Evaluation of soluble organic compounds generated by radiological degradation of asphalt

; Nishikawa, Yoshiaki*; ;

JNC-TN8400 2001-002, 23 Pages, 2000/12

JNC-TN8400-2001-002.pdf:0.55MB

The soluble organic compounds generated by radiological degradation of asphalt ($$gamma$$ ray) were confirmed as a part of influence of the bituminized waste degradation in the TRU waste repositry. Especially, the influence of the nitrate was focused on. As a result, the concentration of the soluble organic compounds generated by radiological degradation of asphalt (10MGy, $$gamma$$ ray which is correspond to absorbed dose of asphalt for 1,000,000years) were lower (each formic acid : about 50mg/dm$$^{3}$$, acetic acid : about 30mg/dm$$^{3}$$ and oxalic acid : about 2mg/dm$$^{3}$$) than that of the formic acid, the acetic acid and the oxalic acid which Valcke et al. had shown (the influence of the organic at the solubility examination which uses Pu and Am). Moreover, the change in the concentration of TOC and the soluble organic compounds (formic acid, acetic acid and oxalic acid) is little under the existence of nitrate ion. That is, the formic acid and acetic acid which can be organic ligands were generated little by oxidative decomposition of asphalt in the process that nitrate ion becomes nitrite ion by radiation. The influence of the soluble organic compounds by the radiological degradation of the asphalt ($$gamma$$ ray) on adsorption and solubility by the complexation of radionuclides in the performance assessment can be limited.

Journal Articles

Electron beam

Hashimoto, Shoji; Arai, Hidehiko

Denki Gakkai Gijutsu Hokoku, (810), p.46 - 50, 2000/10

no abstracts in English

JAEA Reports

Experimental study of gas generation by microorganism

Mine, Tatsuya*; ;

JNC-TN8430 2000-010, 27 Pages, 2000/07

JNC-TN8430-2000-010.pdf:0.72MB

In the geological disposal system of the radioactive wastes, gas generation by microorganism could be significant for the assessment of this system, because organic material included in groundwater, buffer material and wastes might serve as carbon sources for microorganisms. In this study, gas generation tests using microorganisms were carried out under anaerobic condition. The amount of methane and carbon dioxide that were generated by activity of Methane Producing Bacteria (MPB) were measured with humic acid, acetic acid and cellulose as carbon sources. The results showed that methane was not generated from humic acid by activity of MPB. However, in the case of using acetic acid and cellulose, methane was generated, but at high pH condition (pH=10), the amount of generated methane was lower than at low pH (pH=7). It was not clear whether the pH would affect the amount of generated carbon dioxide.

JAEA Reports

Distribution coefficients measurement experiment of americium to Ca-bentonite with cement additives

; Nishikawa, Yoshiaki*; ;

JNC-TN8400 2000-017, 30 Pages, 2000/03

JNC-TN8400-2000-017.pdf:2.87MB

The influence of the cement additives on the distribution coefficients of americium-241 to the Ca-bentonite was confirmed. The adsorption experiment of americium-241 to Ca-bentonite with cement additives was performed by the batch method, as a part of the influence evaluation of the organic in the research of TRU waste disposal. As a result, the distribution coefficient of americium-241 to the Ca-bentonite was over 1.2E+3m$$^{3}$$/kg in the condition of the absence of cement additives. In the case of low concentration (0.3g/kg) of the naphthalenesulfonic acid type cement additives, the distribution coefficient was 5.2E+2m$$^{3}$$kg. And, in the case of high concentration (30g/kg) of the same cement additives, the distribution coefficients was 2.0E-1m$$^{3}$$/kg. On the other hand in the case of flow concentration (0.5g/kg) of the polycarboxylic acid type cement additives, the distribution coefficients was over 1.3E+3m$$^{3}$$/kg. And, in the case of high concentration (50g/kg) of the same cement additives, the distribution coefficient was 1.8E-1m$$^{3}$$/kg. Here, selected cement additives concentrations were based on a standard concentration of 10g/kg when the ratio of water:cement is about one. From these results, the distribution coefficient of americium-241 to the Ca-bentonite decreases according cement additive concentration. The distribution coefficients were similar on different kinds of cement additives. The cement additives concentration influences the distribution coefficient. The distribution coefficient was small in the case of high concentration of the cement additives. That is, it is thought that the cement additives have small influences on the distribution coefficient of americium-241 to the Ca-bentonite in the case of low concentration, though the cement additives have influences on the distribution coefficient of americium-241 to the Ca-bentonite in the case of high concentration.

Journal Articles

Electron bram decomposition of vaporized chloroethenes in air

Hakoda, Teruyuki; Zhang, G.; Hashimoto, Shoji

JAERI-Conf 2000-001, p.211 - 214, 2000/03

no abstracts in English

Journal Articles

Low energy electron beam treatment of VOCs

Hashimoto, Shoji; Hakoda, Teruyuki; Hirota, Koichi; Arai, Hidehiko

Radiation Physics and Chemistry, 57(3-6), p.485 - 488, 2000/03

 Times Cited Count:27 Percentile:14.34(Chemistry, Physical)

no abstracts in English

JAEA Reports

Study on microbial transport and adsorption behavior on engineering barrier for geological disposal of radioactive wastes

Fukunaga, Sakae*; Yokoyama, Hidekazu*; Arai, Kazuhiro*; Asano, Hidekazu*; Senjyu, Takafumi*; Kudo, Akira*

JNC-TJ8400 2000-030, 54 Pages, 2000/02

JNC-TJ8400-2000-030.pdf:1.69MB

It is easy to assume from the past data that microbial transport do not find at 100%-sodium bentonite. Microbial transport do not find at 100%-calcium bentonite too. There are no effects to distribution ration (Kd) of Neptunium (Np) and Plutonium (Pu) with bentonite by sterilizing on low Eh condition (Eh= -500mv). Kd values of Np and Pu show behavior, which are increasing on the hard acidic and alkali conditions. Especially, Kd values of Pu shows one of Kd value is about 100 ml/g on pH=3$$sim$$6, but the other of Kd value is about 400,000 ml/g on pH=13. Precipitating plutonium hydrates occurred the large Kd value on alkali condition.

JAEA Reports

Study on microbial transport and adsorption behavior on engineering barrier for geological disposal of radioactive wastes

Fukunaga, Sakae*; Yokoyama, Hidekazu*; Arai, Kazuhiro*; Asano, Hidekazu*; Senjyu, Takafumi*; Kudo, Akira*

JNC-TJ8400 2000-029, 36 Pages, 2000/02

JNC-TJ8400-2000-029.pdf:1.28MB

It is easy to assume from the past data that microbial transport do not find at 100%-sodium bentonite. Microbial transport do not find at 100%-calcium bentonite too. There are no effects to distribution ration (Kd) of Neptunium (Np) and Plutonium (Pu) with bentonite by sterilizing on low Eh condition (Eh = -500mv). Kd values of Np and Pu show behavior, which are increasing on the hard acidic and alkali conditions. Especially, Kd values of Pu shows one of Kd value is about 100 ml/g on pH = 3$$sim$$6, but the other of Kd value is about 400,000 ml/g on pH = 13. Precipitating plutonium hydrates occurred the large Kd value on alkali condition.

67 (Records 1-20 displayed on this page)