JOPSS - Search Results

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

https://doi.org/10.1524/ract.2009.1602

Times Cited Count：2 Percentile：17.13(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

Solubility of Pu and rare-earths in LiCl-Li $_{2}$ O melt

Kato, Tetsuya*; Sakamura, Yoshiharu*; Iwai, Takashi; Arai, Yasuo

Radiochimica Acta, 97(4-5), p.183 - 186, 2009/05

https://doi.org/10.1524/ract.2009.1592

Times Cited Count：4 Percentile：29.54(Chemistry, Inorganic & Nuclear)

The solubility of Pu and rare-earths were measured in LiCl-Li $_{2}$ O melt where the sesquioxides were precipitated. As shown in the solubility measurement of Pu(III), Nd(III) and Gd(III) at 923 K, the solubility increased proportionally with Li $_{2}$ O concentration in the melt. It was also found that the element of larger ionic radius has higher solubility as far as the trivalent rare-earths and Pu.

Journal Articles

Redox equilibria of Pu $^{4+}$ /Pu $^{3+}$ and PuO $_{2}$ $^{2+}$ /Pu $^{4+}$ couples in molten NaCl-CsCl eutectic as measured by absorption spectrophotometry

Nagai, Takayuki; Uehara, Akihiro*; Fujii, Toshiyuki*; Shirai, Osamu*; Myochin, Munetaka; Yamana, Hajimu*

Radiochimica Acta, 97(4-5), p.209 - 212, 2009/05

https://doi.org/10.1524/ract.2009.1596

Times Cited Count：3 Percentile：23.80(Chemistry, Inorganic & Nuclear)

Redox behavior of uranium and plutonium in molten salts is the essential information for establishing an effective reprocessing process with spent MOX fuel. In an oxide electro-winning reprocessing process, the spent nuclear fuel is dissolved into the molten NaCl-CsCl eutectic, and the dissolved U(VI) and Pu(VI) species are reduced to be dioxides by electrolysis. In the present study, formal redox potentials of the Pu $^{4+}$ /Pu $^{3+}$ and PuO $_{2}$ $^{2+}$ /Pu $^{4+}$ couples in the molten NaCl-CsCl eutectic at 923 K were determined. The fractions of Pu $^{3+}$ , Pu $^{4+}$ , and PuO $_{2}$ $^{2+}$ were determined by UV/Vis/NIR absorption spectrophotometry. PuO $_{2}$ was dissolved into the molten NaCl-CsCl eutectic by Cl $_{2}$ $_{2}$ gas purging. Valences of plutonium (Pu $^{0}$ , Pu $^{3+}$ , Pu $^{4+}$ , and PuO $_{2}$ $^{2+}$ ) were controlled by changing the flow rates of Cl $_{2}$ , O $_{2}$ , and Ar gases.

Journal Articles

Lattice parameters of (U,Pu,Am,Np)O $_{2-x}$

Kato, Masato; Konashi, Kenji*

Journal of Nuclear Materials, 385(1), p.117 - 121, 2009/03

https://doi.org/10.1016/j.jnucmat.2008.09.037

Times Cited Count：47 Percentile：93.12(Materials Science, Multidisciplinary)

Homogeneous MOX fuel containing minor actinide elements has been developed as a fuel of an advanced fast reactor. In this work, the solid solution of (U $_{1-z-y'-y"}$ Pu $_{z}$ Am $_{y'}$ Np $_{y"}$ )O $_{2-x}$ (z=0-1, y'=0-0.12, y"=0-0.07) were investigated by X ray diffraction measurement, and database for the lattice parameter was updated. A model to calculate the lattice parameter was derived from the database using radii of ion composing fluorite structure. The radii of ion were estimated from the lattice parameters measured in this work. The model represented the experimental data within standard deviation of =0.025%.

Journal Articles

Nuclear proliferation-resistance and safeguards for future nuclear fuel cycle

Kuno, Yusuke; Inoue, Naoko; Senzaki, Masao

Journal of Nuclear Materials, 385(1), p.153 - 156, 2009/03

https://doi.org/10.1016/j.jnucmat.2008.10.026

Times Cited Count：3 Percentile：23.80(Materials Science, Multidisciplinary)

Corresponding to the world nuclear security concerns, future nuclear fuel cycle (NFC) should have high proliferation-resistance (PR) and Physical Protection (PP), while promotion of the peaceful use of the nuclear energy must not be inhibited. In order to accomplish nuclear non-proliferation from NFC, a few models of the PR systems should be developed so that international community can recognize them as worldwide norms. To find a good balance of safeguard-ability (so-called extrinsic measure or institutional barrier) and impede-ability (intrinsic feature or technical barrier) will come to be essential for NFC designers to optimize civilian nuclear technology with nuclear non-proliferation, although the advanced Safeguards with high detectability can still play a dominant role for PR in the states complying with full institutional controls. Accomplishment of such norms in a good economic efficiency is a future key challenge.

Journal Articles

A Practical fabrication method for the advanced heterogeneous fuel with magnesia containing minor actinides

Miwa, Shuhei; Osaka, Masahiko

Journal of Nuclear Materials, 385(1), p.165 - 167, 2009/03

https://doi.org/10.1016/j.jnucmat.2008.10.012

Times Cited Count：4 Percentile：29.54(Materials Science, Multidisciplinary)

Journal Articles

Effective thermal conductivity of MOX raw powder

Takeuchi, Kentaro; Kato, Masato; Sunaoshi, Takeo*; Aono, Shigenori; Kashimura, Motoaki

Journal of Nuclear Materials, 385(1), p.103 - 107, 2009/03

https://doi.org/10.1016/j.jnucmat.2008.09.033

Times Cited Count：4 Percentile：29.54(Materials Science, Multidisciplinary)

The effective thermal conductivities were evaluated by measuring radial temperature distribution in MH-MOX powder. The effective thermal conductivities were very small and they changed significantly with O/M, bulk density and atmosphere gas. The results in this work were analyzed by the model of Hamilton and Crosser and the new model for the effective thermal conductivity for MH-MOX powder was derived as a function of powder properties, thermal conductivity of atmosphere gas and temperature.

Journal Articles

Hyperfine interactions in the itinerant system UFeGa $_{5}$

Kambe, Shinsaku; Sakai, Hironori; Tokunaga, Yo; Chudo, Hiroyuki; Yasuoka, Hiroshi; Matsuda, Tatsuma; Haga, Yoshinori; Ikeda, Shugo; Nakamura, Akio; Yamamoto, Etsuji; et al.

Journal of Nuclear Materials, 385(1), p.1 - 3, 2009/03

https://doi.org/10.1016/j.jnucmat.2008.10.030

Times Cited Count：1 Percentile：9.99(Materials Science, Multidisciplinary)

In 5f-electron systems, exotic magnetism and unconventional superconductivity appear at low temperatures owing to strong electron correlations and orbital degeneracy. For example, we have investigated the unconventional superconducting states of recently synthesized NpPdAl (=5K) and PuRhGa (=9K) in terms of both macroscopic (staticsusceptibility, specific heat, resistivity) and microscopic (NMR) probes. The relation between magnetic fluctuations and unconventional superconductivity in f-electron systems is also discussed. Another exciting topic concerns the series AnO (An; U, Np, Pu, Am). Besides the importance of AnO as a nuclear fuel, the magnetic properties of these compounds at low temperatures are particularly interesting. On the basis of $^{17}$ O-NMR studies, multipolar ordered states have been identified in UO (dipolar + quadrupolar ordering) and NpO (quadrupolar + octupolar ordering), in contrast with the non-magnetic ground state of PuO.

Oral presentation

Study of uranium(VI) association with cell surface of microorganisms using functional groups attached electrodes

Onuki, Toshihiko; Suzuki, Yoshinori; Nankawa, Takuya

no journal, ,

Association of uranium with bacterial cell surface has been studied by the functional groups attached silica partiles and ITO and gold electrode. Sorption edge of U(VI) on the COOO $^{-}$ , PO $_{4}$ $^{-}$ attached silica particles was different between them. Reduction of U(VI) with PO $_{4}$ $^{-}$ associated ITO electrode revealed that the reduced U(IV) was still associated with the PO $_{4}$ $^{-}$ functional groups.

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

Solubility of Pu and rare-earths in LiCl-Li $_{2}$ O melt

Redox equilibria of Pu $^{4+}$ /Pu $^{3+}$ and PuO $_{2}$ $^{2+}$ /Pu $^{4+}$ couples in molten NaCl-CsCl eutectic as measured by absorption spectrophotometry

Lattice parameters of (U,Pu,Am,Np)O $_{2-x}$

Nuclear proliferation-resistance and safeguards for future nuclear fuel cycle

A Practical fabrication method for the advanced heterogeneous fuel with magnesia containing minor actinides

Effective thermal conductivity of MOX raw powder

Hyperfine interactions in the itinerant system UFeGa $_{5}$

Study of uranium(VI) association with cell surface of microorganisms using functional groups attached electrodes