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Journal Articles

Migration models of neptunium and americium in groundwater under the present condition of humic substances

Tanaka, Tadao; Sakamoto, Yoshiaki; Sawada, Hiroshi; Ogawa, Hiromichi

JAERI-Conf 2003-010, p.134 - 141, 2003/09

We have performed migration experiments of Np(V) and Am(III) for crushed granite, under the coexistent condition with humic acid substance. As for Np, the periodical concentration changes in the breakthrough curve and the migration velocity of Np passed through the column were not affected by the coexistence of the humic substance. As for Am, on the other hand, the periodical concentration changes in the breakthrough curve were affected by the humic substance concentration. The migration behavior of Am passed through the present column system could be expressed by a migration model taking account of the non-equilibrium state.

Journal Articles

Field tests on migration of TRU-nuclide, 1; General introduction

Ogawa, Hiromichi; Tanaka, Tadao; Mukai, Masayuki; Maeda, Toshikatsu; Munakata, Masahiro; Matsumoto, Junko; Bamba, Tsunetaka; Li, S.*; Wang, Z.*; Li, Z.*; et al.

Nihon Genshiryoku Gakkai Wabun Rombunshi, 2(3), p.332 - 335, 2003/09

The filed migration test using TRU nuclide was carried out as a cooperative research project between JAERI and CIRP (China Institute for Radiation Protection). This report introduced the outline of the filed migration test and described the outline of the special number of Field Test on Migration of TRU-nuclide and main results as a summary report.

Journal Articles

Field tests on migration of TRU-nuclide, 2; Migration test for engineered barrier materials in aerated soil

Maeda, Toshikatsu; Tanaka, Tadao; Mukai, Masayuki; Ogawa, Hiromichi; Yamaguchi, Tetsuji; Munakata, Masahiro; Matsumoto, Junko; Kozai, Naofumi; Bamba, Tsunetaka; Fan, Z.*; et al.

Nihon Genshiryoku Gakkai Wabun Rombunshi, 2(3), p.336 - 341, 2003/09

no abstracts in English

Journal Articles

Field tests on migration of TRU-nuclide, 4; Radionuclide migration test in aquifer soil layer

Tanaka, Tadao; Mukai, Masayuki; Munakata, Masahiro; Maeda, Toshikatsu; Ogawa, Hiromichi; Wang, Z.*; Li, S.*; Yang, Y.*; Zhao, Y.*

Nihon Genshiryoku Gakkai Wabun Rombunshi, 2(3), p.350 - 360, 2003/09

Migration data of $$^{90}$$Sr,$$^{237}$$Np and $$^{238}$$Pu in natural aquifer were collected by a field test, which was performed in an aquifer at 30 m under ground surface of the field test site. Migration parameters for analysis of the results obtained the field test were measured by laboratory column tests and batch tests. Diffusion coefficient corresponding to water velocity was determined from the relationship between water velocity and diffusion length, which obtained from the column tests. Distribution coefficient was determined by considering confident ability of data, test conditions, and environmental conditions. One dimensional migration behavior of the radionuclides in aquifer, calculated by using the migration parameters obtained from the batch and column tests, agreed with the results obtained from the field test. It was confirmed that the migration behavior of alpha-nuclides could be evaluated by applying the conventional equation for evaluating the radionuclide migration and the migration parameters obtained from laboratory tests.

Journal Articles

Field tests on migration of TRU-nuclide, 3; Migration test of radionuclide in aerated soil layer

Mukai, Masayuki; Tanaka, Tadao; Maeda, Toshikatsu; Ogawa, Hiromichi; Matsumoto, Junko; Munakata, Masahiro; Zhao, Y.*; Guo, Z.*; Ni, S.*; Li, S.*

Nihon Genshiryoku Gakkai Wabun Rombunshi, 2(3), p.342 - 349, 2003/09

Evaluation of radionuclide migration in geologic media is of great importance in safety assessment for shallow land disposal specially for TRU nuclides because of inadequate data based on field test. As a cooperative research between JAERI and CIRP, a field test of radionuclide migration was conducted under natural condition using Sr-90, Np-237 and Pu-238 to obtain migration data of the radionuclides in actual aerated layer under natural rainfall condition. Values of input parameters to an existing evaluation equation of nuclide migration were determined on the basis of the results of laboratory experiments of batch and column methods and field investigation. Migration distribution of the radionuclides calculated with the determined values showed reasonable agreement with the measured distribution of the field test. This confirmed an applicability of the evaluation equation for radionuclide migration to actual aerated layer under natural condition.

Journal Articles

Field tests on migration of TRU-nuclide, 5; Validation study of safety assessment code system of shallow land disposal (GSA-GCL)

Munakata, Masahiro; Kimura, Hideo; Tanaka, Tadao; Mukai, Masayuki; Maeda, Toshikatsu; Ogawa, Hiromichi

Nihon Genshiryoku Gakkai Wabun Rombunshi, 2(3), p.361 - 367, 2003/09

no abstracts in English

Journal Articles

Migration mechanisms of $$^{237}$$Np and $$^{241}$$Am through loess media

Tanaka, Tadao; Mukai, Masayuki; Maeda, Toshikatsu; Matsumoto, Junko; Ogawa, Hiromichi; Li, Z.*; Wang, X.*; Fan, Z.*; Guo, L.*; Liu, C.*

Journal of Radioanalytical and Nuclear Chemistry, 256(2), p.205 - 211, 2003/05

 Times Cited Count:3 Percentile:25.81(Chemistry, Analytical)

Migration experiments of $$^{237}$$Np(V) and $$^{241}$$Am(III) have been performed using a column system, to investigate migration behavior of Np and Am through a column packed with loess, taken from Shanxi, China. Adsorption mechanisms of Np and Am on the loess were examined by a chemical extraction method. In the case of the Np, most of Np adsorbed on the influent edge of the column. The Np adsorbed on the loess was mainly controlled by surface complexation. However, the migration of Np in the loess media could be roughly evaluated by using the distribution coefficient. In the case of the Am, particulate Am species was formed in the influent solution and moved in the column. The Am adsorbed on the loess was controlled by irreversible reactions. The migration behavior of particulate Am in the loess media could be expressed by the filtration theory.

Journal Articles

The Suppression effect of natural barrier for the radionuclide migration under the practice environment

Tanaka, Tadao; Mukai, Masayuki; Maeda, Toshikatsu; Matsumoto, Junko; Ogawa, Hiromichi; Munakata, Masahiro; Kimura, Hideo; Bamba, Tsunetaka; Fujine, Sachio

Genshiryoku eye, 49(2), p.76 - 79, 2003/02

no abstracts in English

Journal Articles

Migration behavior of stable and radioactive strontium in natural aquifer

Tanaka, Tadao; Mukai, Masayuki; Maeda, Toshikatsu; Munakata, Masahiro; Matsumoto, Junko; Ogawa, Hiromichi; Bamba, Tsunetaka*; Wang, Z.*; Yang, Y.*; Zhao, Y.*

Proceedings of International Symposium on Radioecology and Environmental Dosimetry, p.179 - 184, 2003/00

Migration behaviors of stable strontium element and radioactive nuclide strontium 90 in natural aquifer were studied by a field test, which was performed in the aquifer loess zone at 30 m under the ground surface of the field test site of China Institute for Radiation Protection. The migration behavior of stable strontium was a little different from that of $$^{90}$$Sr. The difference was evaluated by applying the distribution coefficient considering Sr and coexistent ion concentrations. Migration behavior of radionuclide in natural environment has been generally demonstrated on field tests without radioactive tracers and/or large-scale column tests with radioactive tracers. Such tests seem to be valuable to improve reliability of the migratory evaluation.

JAEA Reports

Survey of the geological characteristics on the Japanese Islands for disposal of RI and research institute waste

Hagiwara, Shigeru*; Sakamoto, Yoshiaki; Takebe, Shinichi; Ogawa, Hiromichi; Nakayama, Shinichi

JAERI-Review 2002-038, 107 Pages, 2002/12

JAERI-Review-2002-038.pdf:6.72MB

For the disposal of radioactive waste arising from radioactive utilization facilities and nuclear facilities, it is necessary to establish the disposal system in proportion to half-lives of radionuclides and radioactivity concentration in the waste. It is important to grasp the features of the earth scientific phenomena and geological structure of our country for the disposal system of radioactive waste. Then, for the porpose of the survey of the geological characteristics around the Japanese Islands whole neiborhood, the earth scientific phenomena at present, geological structure and geotectonic history were summarized on the basis of the existing literatures.

JAEA Reports

Adsorption mechanisms and models of $$^{85}$$Sr, $$^{237}$$Np, $$^{238}$$Pu and $$^{241}$$Am in loess media (Joint research)

Tanaka, Tadao; Mukai, Masayuki; Maeda, Toshikatsu; Matsumoto, Junko; Ogawa, Hiromichi; Li, S.*; Wang, Z.*; Wang, J.*; Guo, Z.*; Zhao, Y.*

JAERI-Research 2002-034, 20 Pages, 2002/12

JAERI-Research-2002-034.pdf:1.1MB

Adsorption mechanisms and models of $$^{85}$$Sr(II), $$^{237}$$Np(V), $$^{238}$$Pu(IV) and $$^{241}$$Am(III) on the loess were investigated from their adsorption and desorption properties. The distribution coefficient of $$^{85}$$Sr and $$^{237}$$Np was 2 - 3 orders of magnitude smaller than that of $$^{238}$$Pu and $$^{241}$$Am. The adsorption of $$^{85}$$Sr and $$^{237}$$Np was mainly controlled by the ion exchange reaction. On the other hand, the adsorption of $$^{238}$$Pu and $$^{241}$$Am was mostly controlled by the selective chemical reactions with Fe and Mn oxyhydroxide/oxide and humic substances. On the basis of the experimental results, several types of adsorption models of the radionuclides, considering elemental concentrations, adsorption mechanisms and kinetics, were proposed for setting up the analytical systems of radionuclide migration in the loess media.

Journal Articles

Sorption and reduction of Neptunium(V) on the surface of iron oxides

Nakata, Kotaro*; Nagasaki, Shinya*; Tanaka, Satoru*; Sakamoto, Yoshiaki; Tanaka, Tadao; Ogawa, Hiromichi

Radiochimica Acta, 90(9-11), p.665 - 669, 2002/12

 Times Cited Count:49 Percentile:93.73(Chemistry, Inorganic & Nuclear)

Sorption and desorption experiments of Np on magnetite and hematite under aerobic and anaerobic conditions were carried out to investigate the possibility of reduction of Np(V) to Np(IV) on the surfave of iron oxides including Fe(II). The results indicated that Np sorption mechanism on magnetite under anaerobic condition was completely different from that under aerobic condition. The evidence of the presence of Np(IV) on magnetite surface after sorption was obtained from the extraction experiment with TTA/xylene solution.

JAEA Reports

The Geological characteristics during the quaternary period around Japanese Islands

Hagiwara, Shigeru*; Sakamoto, Yoshiaki; Ogawa, Hiromichi; Nakayama, Shinichi

JAERI-Review 2002-024, 203 Pages, 2002/11

JAERI-Review-2002-024.pdf:15.79MB

Radioactive wastes arising from radioisotope facilities and nuclear research facilities should be disposed of in the surface of the earth, the shallow underground,the adequate depth and the deep undergruond according to radioactivity concentration, and should be managed during several hundreds years. For the selection of disposal site, it is necessary to survey the beginning of earth scientific phenomena observed in the Japanese Islands at present and to reconnoiter the prospective features. This report reviewed on the genesis and classification of sediments, earth scientific phenomena observed in the Japanese Islands and the feature of each place(10 districts) concerning to the Quaternary period in the newest geological time unit.

Journal Articles

Sorption characteristics of actinium and protactinium onto soils

Sakamoto, Yoshiaki; Ishii, Tomoaki*; Inagawa, Satoshi*; Gunji, Yasuyoshi*; Takebe, Shinichi; Ogawa, Hiromichi; Sasaki, Tomozo*

Journal of Nuclear Science and Technology, 39(Suppl.3), p.481 - 484, 2002/11

Sorption behavior of 227Ac and 233Pa onto several kinds of soils has been studied with a sequential extraction technique, for safety assessment of shallow land disposal of uranium bearing waste. After a batch sorption experiment, the sorbed form of 227Ac and 233Pa onto the soils was fractionated into ion exchange form (extraction by KCl+CaCl2), association with Fe+Mn oxides (extraction by NH2OH-HCl and oxalic acid), association with organic materials (extraction by H2O2) and fixation into soil (residual). From the results of the sequential extraction, major part of 227Ac sorbed onto the soils was found in the fraction of the ion exchange form and the fixation into the soils. On the other hand, major part of 233Pa was found in the fraction of the association with Fe+Mn oxides and the fixation into the soils. These results suggest that the sorption behavior of 227Ac and 233Pa is related to the irreversible sorption reaction onto the soils.

Journal Articles

Sorption behavior of plutonium(IV) onto soils in the presence of humic acid

Tanaka, Tadao; Nagao, Seiya; Sakamoto, Yoshiaki; Ogawa, Hiromichi

Journal of Nuclear Science and Technology, 39(Suppl.3), p.524 - 527, 2002/11

Influence of humic acid on the sorption of Pu onto a coastal sand, which does not sorb humic acid, and an ando soil, which sorbs humic acid very well, was examined with respect to molecular sizes of humic acid. Sorption affinity of Pu for the coastal sand decreased with increasing humic acid concentration. As to the ando soil, the sorption affinity of Pu in the presence of humic acid was larger than that in the absence of humic acid, in low humic acid concentration range. These results suggest that apparent sorption affinity of Pu on the soils is dependent on the complexation ability with humic acid and the sorption affinity of the resulting humic complexes. Concentration profiles of Pu in each size fraction of solution before and after the sorption experiment were obtained by ultrafiltration technique. It was found that the complexation and sorption properties of humic acid are dependent on its molecular size and the important molecular size relating to the complexation and sorption properties tends to shift into smaller size ranges with increasing humic acid concentration.

Journal Articles

In situ ATR-FTIR spectroscopy for functional groups of humic substances complexing with metal ions

Tanaka, Tadao; Sakamoto, Yoshiaki; Ogawa, Hiromichi

Genshiryoku Bakkuendo Kenkyu, 9(1), p.29 - 34, 2002/09

To obtain structural information on functional groups of humic substances complexing with metal ions, infrared (IR) spectral analysis of the humic substances dissolving in aqueous solutions has been studied by ATR (Attenuated Total Reflection) method. By using the ATR method, IR spectral shifts of humic substance due to complexation with metal ions were observed. The observation provided with information on complexation kinetics, and on characteristics of functional groups depending on solvent properties, such as pH and solute concentrations. These information was difficult to be obtained by conventional FTIR spectroscopy using powdered humic substances. The obtained results show that IR spectral shifts on the functional groups of the humic substances complexed with metal ions could be possibly characterized ${it in situ}$ by using the ATR-FTIR spectroscopy.

Journal Articles

Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) spectroscopy of functional groups of humic acid dissolving in aqueous solution

Tanaka, Tadao; Nagao, Seiya; Ogawa, Hiromichi

Analytical Sciences (CD-ROM), 17(Suppl.), p.1081 - 1084, 2002/03

Structural information of humic acid dissolving in aqueous solution has been studied by ATR-FTIR spectroscopy. Two types of humic acid fractions were prepared: one is dominated by aliphatic structure and another is dominated with aromatic structure. The functional groups of both fractions have been characterized with respect to their ATR-FTIR spectral structures (ATR spectra) measured in pH range of 2 - 10. The ATR spectra were compared with the infrared spectra of the freeze-dried humic acid fractions, which were obtained using transmission Fourier transform infrared spectroscopy with KBr pellet (KBr spectra) and using diffuse reflectance infrared Fourier transform spectroscopy (DRS spectra). In a comparison between spectra obtained from the three infrared spectroscopic methods, the major absorptions of the ATR spectra for both fractions are in well agreement with those of the KBr spectra and the DRS spectra, each other. These show that the functional groups of the humic acid dissolving in aqueous solution could characterize by using the ATR-FTIR spectroscopy.

Journal Articles

Fluorescence quenching studies of Eu-humic complexes by three-dimensional excitation emission matrix spectroscopy

Nagao, Seiya; Aoyama, Masakazu*; Watanabe, Akira*; Nakaguchi, Yuzuru*; Ogawa, Hiromichi

Analytical Sciences (CD-ROM), 17(Suppl.), p.1585 - 1588, 2002/03

no abstracts in English

Journal Articles

Effect of temperature on the sorption of neptunium on magnetite

Nakata, Kotaro*; Nagasaki, Shinya*; Tanaka, Satoru*; Sakamoto, Yoshiaki; Tanaka, Tadao; Ogawa, Hiromichi

JAERI-Conf 2002-004, p.667 - 673, 2002/03

no abstracts in English

Journal Articles

Alteration-phase formation and associated cesium release during alteration of R7T7 waste glass

Inagaki, Yaohiro*; Idemitsu, Kazuya*; Arima, Tatsumi*; Maeda, Toshikatsu; Ogawa, Hiromichi; Itonaga, Fumio

Materials Research Society Symposium Proceedings, Vol.713, p.589 - 596, 2002/00

A large number of studies on HLW glass corrosion have shown that the glass reacts with water to form more stable mineral phases (alteration phases) during the long-term geological disposal. The phase formation is essential to evaluate the radionuclide release from the glass during the long-term disposal. The purpose of this study is to evaluate, experimentally, the mineral phase formation from HLW glass and the associated cesium release. Static corrosion tests were performed on powdered R7T7 glass in alkalline solutions at elevated temperatures to accelerate the reaction, and mineral phases formed were analyzed by XRD. The results showed that analcime (zeolite) is formed as the dominant phase coexisting with SiO$$_{2}$$(am), and beidellite(smectite) or gibbsite coexists dependiting on the conditions. The solution analysis indicated that most of the cesium is retained in the phases of beidellite and analcime by sorption.

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