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Journal Articles

Formation constants of Eu(III)-carboxylates determined by ion-selective liquid membrane electrode

Sasaki, Takayuki*; Yoshida, Hatsumi*; Kitatsuji, Yoshihiro; Takagi, Ikuji*; Moriyama, Hirotake*

Chemistry Letters, 40(8), p.870 - 871, 2011/08

 Times Cited Count:0 Percentile:100(Chemistry, Multidisciplinary)

Trivalent metal ion selective electrode (ISE) consisting of bis-(diphenylphosphoryl)-methane as an ionophore was developed for the determination of formation constants with organic ligands. The ISE prepared exhibited Nernstian response to the concentration of Eu$$^{3+}$$ in the test solutions. Even in the presence of carboxylic acids such as malonic acid in samples, the obtained potential values were found to be stable and reproducible during the measurement time. The present formation constants of Eu with carboxylates were in good agreement with the reported values.

Journal Articles

Trends of fast reactor cycle technology development in the world, 3 (Last of serial); Advanced sodium-cooled fast reactor cycle technology and development issues

Yamaguchi, Akira*; Yanagisawa, Tsutomu; Moriyama, Hirotake*

Nippon Genshiryoku Gakkai-Shi, 52(10), p.626 - 637, 2010/10

This article introduces the innovative technologies that examine the adoption to the sodium-cooled fast reactor as an approach for commercial use of the fast reactor cycle system, as the final of serial, mainly by International Conference (FR09) organized by IAEA and held in December, 2009. The latest situation of the research and development and the simulation technology concerning a reactor technologies such as the reactor configuration, the reactor system design, and the cooling system devices are reviewed. Fuel development, wet reprocessing and pyro-reprocessing technologies are also reviewed by the views for the future. In addition, the problem of safety, a nuclear nonproliferation, an operating experience, a technological transfer between generation, and the human resource is described, including the expectation to Japan by the utilization of Monju and Joyo.

Journal Articles

Separation factor of americium from cerium in molten chloride-liquid gallium reductive extraction system

Toda, Taro*; Maruyama, Takehiro*; Moritani, Kimikazu*; Moriyama, Hirotake*; Hayashi, Hirokazu

Denki Kagaku Oyobi Kogyo Butsuri Kagaku, 77(8), p.649 - 651, 2009/08

 Times Cited Count:5 Percentile:84.8(Electrochemistry)

The distribution coefficients of Am and Ce were measured in the eutectic LiCl-KCl/liquid Ga system at 773K. By using ZrCl$$_4$$ as the oxide ion scavenger in order to avoid the formation of such oxychlorides as MO$$^{(n-2)+}$$, the effect of oxide ion concentration was well controlled on the distribution coefficients of Am and Ce. The separation factor between Am and Ce was then obtained to be about 100. By comparing the present value with the other experimental and the predicted ones, it was confirmed that the Ga system was more selective than the Bi and Cd system.

Journal Articles

Effect of oxide ions on separation factors of actinides from lanthanides in reductive extraction

Moriyama, Hirotake*; Moritani, Kimikazu*; Toda, Taro*; Hayashi, Hirokazu

Radiochimica Acta, 97(4-5), p.233 - 236, 2009/05

 Times Cited Count:1 Percentile:87.94(Chemistry, Inorganic & Nuclear)

The distribution coefficients of Am, Ce, and Eu between the salt and metal phases were measured at 1073 K in a reductive extraction system of equimolar NaCl-KCl melt and liquid Ga, which were expected to be higher from a thermodynamic point of view. By changing some solute concentrations, it was observed that the distribution coefficients were much dependent on the oxide ion concentration in the system, possibly due to the formation of such compounds as AmO$$^+$$ and CeO$$^+$$. Also, in some runs, the mass balance of Am was affected possibly by the formation and precipitation of its oxychloride and/or oxide. By taking the observations into consideration, the separation factor between Am and Ce was obtained to be about 30 as a lower limit in the present system.

Journal Articles

Deuterium diffusion in a chemical densified coating observed by NRA

Takagi, Ikuji*; Kobayashi, Takashi*; Ueyama, Yutaka*; Moriyama, Hirotake*; Nakamichi, Masaru; Nakamura, Hirofumi; Hayashi, Kimio

Journal of Nuclear Materials, 386-388, p.682 - 684, 2009/04

 Times Cited Count:5 Percentile:57.79(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Thermodynamic properties of lanthanides and actinides for reductive ectraction of minor actinides

Toda, Taro*; Maruyama, Takehiro*; Moritani, Kimikazu*; Moriyama, Hirotake*; Hayashi, Hirokazu

Journal of Nuclear Science and Technology, 46(1), p.18 - 25, 2009/01

 Times Cited Count:26 Percentile:10.97(Nuclear Science & Technology)

The excess thermodynamic quantities of lanthanides and actinides in molten salts and liquid metals were studied for reductive extraction of minor actinides. The excess enthalpies and entropies of those elements in the molten chloride phase were found to be correlated with the ionic radii of metal ions possibly due to complex formation. In the liquid metal phase, on the other hand, the excess enthalpies were explained with Miedema's atomistic model and the excess entropies were explained with the vibrational entropy due to alloy formation. Using these correlations and models, some missing values of the excess thermodynamic quantities were evaluated and the separation factors of minor actinides from lanthanides were calculated in different reductive extraction systems. The higher separation factors were obtained in the system using aluminum or gallium than in the system using bismuth or cadmium as the liquid metal phase.

Journal Articles

Reductive extraction of minor actinides from molten chloride into liquid gallium

Toda, Taro*; Maruyama, Takehiro*; Moritani, Kimikazu*; Moriyama, Hirotake*; Hayashi, Hirokazu

Proceedings of 2008 Joint Symposium on Molten Salts (USB Flash Drive), p.933 - 938, 2008/10

The distribution coefficients of Am and Ce were measured in the LiCl-KCl/Ga system at 773 K. By using ZrCl$$_4$$ as the oxide ion scavenger in order to avoid the formation of such oxychlorides as CeO$$^+$$ and AmO$$^+$$, the effect of oxide ion concentration was well controlled on the distribution coefficients of Am and Ce. The separation factor between Am and Ce was then obtained to be about 100. By comparing the present value with the other experimental and the predicted ones, it was confirmed that solvent metals were ordered from the most selective to the less selective one as Al$$>$$Ga$$>$$Bi$$>$$Cd.

Journal Articles

Study on stabilization effect of neutral soft donor on trivalent lanthanide and actinide dicarboxylate complexes by time-resolved laser-induced fluorescence spectroscopy

Sasaki, Takayuki*; Kubo, Shintaro*; Kobayashi, Taishi*; Kirishima, Akira*; Kimura, Takaumi; Kubota, Takumi*; Takagi, Ikuji*; Moriyama, Hirotake*

Journal of Nuclear and Radiochemical Sciences, 6(1), p.51 - 54, 2005/07

no abstracts in English

Journal Articles

Chlorination of UO$$_{2}$$, PuO$$_{2}$$ and rare earth oxides using ZrCl$$_{4}$$ in LiCl-KCl eutectic melt

Sakamura, Yoshiharu*; Inoue, Tadashi*; Iwai, Takashi; Moriyama, Hirotake*

Journal of Nuclear Materials, 340(1), p.39 - 51, 2005/04

 Times Cited Count:23 Percentile:14.61(Materials Science, Multidisciplinary)

A new chlorination method using ZrCl$$_{4}$$ in a molten salt has been investigated for the pyrometallurgical reprocessing of spent oxide fuels. UO$$_{2}$$, PuO$$_{2}$$ and rare earth oxides(La$$_{2}$$O$$_{3}$$, CeO$$_{2}$$, Nd$$_{2}$$O$$_{3}$$ and Y$$_{2}$$O$$_{3}$$) were allowed to react with ZrCl$$_{4}$$ in a LiCl-KCl eutectic salt at 500$$^{circ}$$C to give a metal chloride solution and a precipitate of ZrO$$_{2}$$. By keeping the system quite still, the solution settled so that the ZrO$$_{2}$$ precipitate could be separated.

JAEA Reports

Study on Solution Species and Thermodynamic Data of Multivalent Metal Ions

Moriyama, Hirotake*

JNC-TJ8400 2004-029, 45 Pages, 2005/02

JNC-TJ8400-2004-029.pdf:1.01MB

In support of the safety assessment of geologic disposal of high level radioactive wastes, solubility measurement of Zr(IV) was performed in a pH range from 1 to 14 at ionic strength of 0.1, 0.5 and 1.0M. The values of solubility product and hydrolysis constant were obtained from the solubility data. Also, the polynuclear hydrolysis constants reported for hexavalent actinide ions were examined by using a hard sphere model, and some predictions were made.

JAEA Reports

Study on Hydrolysis and Complexation Reactions of Transuranium Elements III

Moriyama, Hirotake*

JNC-TJ8400 2003-058, 41 Pages, 2004/02

JNC-TJ8400-2003-058.pdf:1.84MB

In support of the safety assessment of geologic disposal of high level radioactive wastes, solubility measurement of U(IV) in alkaline solution was performed. The solubility of U(IV) was observed to increase in alkaline solution, and the hydrolysis constants beta$$_{5}$$$$^{o}$$and beta$$_{6}$$$$^{o}$$were obtained. Reported thermodynamic data of solubility products, hydrolysis constants and complexation constants were also compared and discussed. It was found that uncertainty of the reported beta$$_{4}$$$$^{o}$$values of tetravalent actinide ions is still large. The beta$$_{4}$$$$^{o}$$values were estimated by using a hard sphere model extended to 8 coordination, showing that such large uncertainty is due to the effect of colloid formation.

Journal Articles

Measurement method of the distribution coefficient on sorption process; On until now history and situation on the standardization in the AESJ

Takebe, Shinichi; Fujiwara, Keiji*; Moriyama, Hirotake*

Nippon Genshiryoku Gakkai "Shisetsu, Kankyo Hoshano Dotai" Kenkyu Senmon Iinkai Hokokusho, p.1 - 9, 2003/03

no abstracts in English

JAEA Reports

Study on Hydrolysis and Complexation Reactions of Transuranium Elements II

Moriyama, Hirotake*

JNC-TJ8400 2002-054, 34 Pages, 2003/02

JNC-TJ8400-2002-054.pdf:0.14MB

In support of the safety assessment of geologic disposal of high level radioactive wastes, hydrolysis reactions of U(IV) were studied. The hydrolysis constants of tetravalent uranium were determined by solvent extraction method using thenoyltrifluoroacetone(TTA) and $$^{233}$$U. The distribution ratio of U(IV) was measured as a function of the pH$$_{c}$$ value in the aqueous phase at I=0.1, 0.5 and 1.0, and was analyzed to obtain the hydrolysis constants of $ss $_{1}$$, $ss $_{2}$$ and $ss$_{3}$$ at the standard state (I=0). The higher order hydrolysis constants of $ss $_{5}$$ and $ss$_{6}$$ were also obtained from the results of the solubility measurement at a high pH condition. The systematic behavior of the hydrolysis constants was by using an improved hard sphere model.

JAEA Reports

None

*; Fujii, Toshiyuki*; Moriyama, Hirotake*; ; ; Myochin, Munetaka; Ojima, Hisao

JNC-TY8400 2002-013, 57 Pages, 2002/03

JNC-TY8400-2002-013.pdf:32.32MB

no abstracts in English

JAEA Reports

Utilization of actinide as cell active materials; Effective utilization of uranium as battery active material, JAERI's nuclear research promotion program, H10-034-2 (Contract research)

Yamana, Hajimu*; Moriyama, Hirotake*; Asano, Hideki*; Shiokawa, Yoshinobu*; Yamamura, Tomoo*; Hasegawa, Kazuki*; Kimura, Akihiro*; Umekita, Satoshi*

JAERI-Tech 2002-018, 33 Pages, 2002/03

JAERI-Tech-2002-018.pdf:1.95MB

no abstracts in English

JAEA Reports

Study on hydrolysis and complexation reactions of transuranium elements

Moriyama, Hirotake*

JNC-TJ8400 2001-048, 40 Pages, 2002/02

JNC-TJ8400-2001-048.pdf:0.16MB

In support of the safety assessment of geologic disposal of high level radioactive wastes, hydrolysis and complexation reactions of transuranium elements were studied. For comparison with the case of Pu(IV), the solubility of UO$$_{2}$$.xH$$_{2}$$O was measured under a reducing condition, and the solubility product K$$^{0}_{sp}$$ and some hydrolysis constants were obtained. Similarly to the value of Pu(IV), the obtained K$$^{0}_{sp}$$ value was found to be considerably smaller than that predicted by Rai et al. from its dependence on ionic radius. Also, the solubility of UO$$_{2}$$(OH)$$_{2}$$ under an oxidizing condition was measured, and the solubility product K$$^{0}_{sp}$$ was obtained. For complexation, furthermore, it was examined by using an improved hard sphere model to predict some complexation constants of actinide ions which were lacked in literatures.

JAEA Reports

Study on solubility of transuranium elements, III

Moriyama, Hirotake*

JNC-TJ8400 2001-015, 48 Pages, 2001/03

JNC-TJ8400-2001-015.pdf:1.05MB

In suport of the safety assessment of geologic disposal of high level radioactivc wastes, the solubility of transuranium elements was studied. The ionic strength dependence of solubility of PuO$$_{2}$$$$cdot$$xH$$_{2}$$O was measured under a reducing condition, and the solubility product K$$^{0}_{sp}$$ was obtained. The obtained K$$^{0}_{sp}$$ value was found to be much smaller than that predicted by Rai et al. from its dependence on ionic radius. Also, the systematic trends of complex formation constants of actinide ions were cxamined by using an improved hard sphere model. It was found that the systematic trends of the literature values for actinide ions other than An$$^{4+}$$ were well explained by the present model. The reliability of the literature values for An$$^{4+}$$ would be checked.

JAEA Reports

Study on solubility of transuranium elements, II

Moriyama, Hirotake*

JNC-TJ8400 2000-050, 47 Pages, 2000/03

JNC-TJ8400-2000-050.pdf:1.49MB

In support of the safety assessment of geologic disposal of high levcl radioactive wastes, the solubility of transuranium elements was studied. The solubility of PuO$$_{2}$$$$cdot$$xH$$_{2}$$O was measured undcr a reducing condition, and the solubility product K$$^{0}_{sp}$$ and the stability constant $$beta$$$$_{4}$$ of Pu(OH)$$_{4}$$ were obtained. The obtained K$$^{0}_{sp}$$ value was found to be much smaller than that predicted by Rai et al. from its dependence on ionic radius. Also, the solubility of PuO$$_{3}$$3 $$cdot$$ xH$$_{2}$$O was measured under an oxidizing condition and the solubility product K$$^{0}_{sp}$$ was obtained. In the analysis of hydrolysis constants of actinide ions, it was found that the systematic trend of the hydrolysis constants was well explained by the hard sphere model considering the effective charges of actinide ions.

JAEA Reports

Study on solubility of transuranium elements

Moriyama, Hirotake*

JNC-TJ8400 99-060, 26 Pages, 1999/02

JNC-TJ8400-99-060.pdf:0.74MB

In support of the safety assessment of geologic disposal of high level radioactive wastes, the solubility of transuranium elements was studied. The solubility of plutonium was measured in an aqueous solution of pH3-8 under reducing conditions, and the obtained results were well explained by considering the presence of the solution species of Pu(III) in equilibrium with the solid phase of PuO$$_{2}$$(am). Also, systematic behavior of hydrolysis constants of actinide ions was studied with the help of a simple hard sphere model. The literature data of the hydrolysis constants of actinide ions were analyzed by the model and systematic trends were explained by taking into account the effective charges of actinide ions. Such a model is useful to check the experimental data and to predict the unknown data from a systematic point of view.

JAEA Reports

None

Moriyama, Hirotake*

PNC-TJ1604 92-003, 39 Pages, 1992/03

PNC-TJ1604-92-003.pdf:0.39MB

no abstracts in English

22 (Records 1-20 displayed on this page)