Relativistic density-functional study of solid solubitilty of tansiton metal/-uranium alloys; The Roll of d-d orbital interactions

Kurihara, Masayoshi*; Onoe, Jun*; Hirata, Masaru; Suzuki, Chikashi

Journal of Alloys and Compounds, 509(4), p.1152 - 1156, 2011/01

https://doi.org/10.1016/j.jallcom.2010.08.153

The alloying behavior of transition metals (TMs) in solid -phase uranium (-U), which is expected to be used as fuel for next-generation nuclear reactors, is investigated using the discrete-variational Dirac-Fock-Slater molecular orbital method. Using a model cluster, U/TM, as the minimum unit of -U/TM alloys, we evaluate the d-orbital energy of the TM (Md), the bond order between the TM and U atoms, and the orbital overlap population (OOP) between the atomic orbitals of the TM and U atoms. We subsequently examine the effect of these quantities on the maximum solid solubility (MSS) of the -U/TM alloys. Md and the OOP (U 6d-TM d) exhibit good correlations with the MSS for -U/TM alloys, so that the interaction between the U-6d and TM-d atomic orbitals is found to play a key role in determining the MSS of the -U/TM alloys. The magnitude of the MSS can be explained in terms of the stabilization energy caused by U 6d-TM d orbital interactions for -U/TM alloys, which is affected by the Md and the OOP. The exponential dependence of the MSS on Md and the OOP is explained in terms of the equilibrium constant obtained using a substitution cluster model for -U/TM alloys. We also map the MSS of -U/TM alloys using the Md and the OOP as the alloying parameters. These results will assist the quantum design of nuclear fuel materials for other alloy systems besides the present alloy system.

Theoretical study on the alloying behavior of -uranium metal; -uranium alloy with 3d transition metals

Kurihara, Masayoshi*; Hirata, Masaru; Sekine, Rika*; Onoe, Jun*; Nakamatsu, Hirohide*

Journal of Nuclear Materials, 326(2-3), p.75 - 79, 2004/03

https://doi.org/10.1016/j.jnucmat.2003.11.013

We have investigated the alloying behavior of g-uranium with 3d transition metals (TMs) using the relativistic discrete-variational Dirac-Fock-Slater (DV-DFS) method. The d-orbital energy (Md) as an alloying parameter well reproduces the alloying behavior of g- uranium metal with TMs: (1) in the case of a large Md value (Ti,V,Cr), the solubility of these TM elements in g-uranium becomes large; (2) in the case of a middle Md value (Mn,Fe,Co), the tendency to form a uranium intermetallic compound with these elements becomes stronger; (3) in the case of a small Md value (Cu), the alloying element is insoluble in g-uranium. The alloying behavior of g-uranium with TMs is also discussed in terms of other parameters such as electronegativity and metallic radius.

Electronic structures and chemical bonding of actinyl nitrates dihydrates

Hirata, Masaru; Tachimori, Shoichi; Sekine, Rika*; Onoe, Jun*; Nakamatsu, Hirohide*

Advances in Quantum Chemistry, Volume 37, p.335 - 351, 2001/00

https://doi.org/10.1016/S0065-3276(00)37024-1

no abstracts in English

Status on the heavy elements research using the DV-DFS method

Hirata, Masaru; Bastug, T.*; Sekine, Rika*; Onoe, Jun*; Nakamatsu, Hirohide*; Mukoyama, Takeshi*

JAERI-Review 99-008, 29 Pages, 1999/03

JAERI-Review-99-008.pdf:1.45MB

no abstracts in English

Electronic structures of actinyl nitrate-triethyl phosphate complexes using the DV-DS method

Hirata, Masaru; Sekine, Rika*; Onoe, Jun*; Nakamatsu, Hirohide*; Mukoyama, Takeshi*; ; Tachimori, Shoichi

Journal of Alloys and Compounds, 271-273, p.128 - 132, 1998/00

https://doi.org/10.1016/S0925-8388(98)00039-5

no abstracts in English

Relationship between progress of borehole investigations and geometric data of fractures at crystalline rocks

Ishibashi, Masayuki; Sasao, Eiji; Nakajima, Makoto*; Atsumi, Hiroyuki*; Onoe, Hironori; Saegusa, Hiromitsu; Kawabata, Junichi*; Masumoto, Kazuhiko*; Seno, Shoji*; Iwano, Keita*

no journal, , 

no abstracts in English

Adsorption study on PGM elements by AlHCF from nitric acid solution

Mishima, Ria; Tachioka, Sotaro*; Inaba, Yusuke*; Harigai, Miki*; Matsumura, Tatsuro; Watanabe, Shinta*; Onoe, Jun*; Nakase, Masahiko*; Takeshita, Kenji*

no journal, , 

In Japan, the final disposal of high level liquid waste (HLLW) will be done after vitrification into borosilicate glass and then disposed into deep underground. In this vitrification process, there are some concerns. The first concern is precipitation of platinum group metals (PGMs) in the melter due to their low solubility into borosilicate glass. The second concern is the formation of yellow phase caused by Mo content. The final concern is the generation of huge number of vitrified glasses and the requirement of wide space needed for final disposal. Among many kinds of extractants and adsorbents for separation of such metal ions, metal hexacyanoferrate (HCFs) were reported to have an ability to adsorb PGMs. The objective of this study is to elucidate the adsorption behavior of aluminum hexacyanoferrate (AlHCF) for various metal ions and understand the relation between elution and adsorption. The effect of synthetic and workup conditions on PGM and Mo adsorption from simulated HLLW (sHLLW) was surveyed. Also, the relationship between adsorption of metal ions and elution of the AlHCF was studied. The synthesized AlHCF showed adsorption performance for PGMs and Mo in simulated HLLW. As a result of an adsorption test with a Pd single component solution to investigate the adsorption mechanism, the eluted element ratio was Fe:Al = 1:4 in the Pd adsorption test. However, the element ratio was Fe:Al = 3:4 in the original AlHCF. Therefore, it was suggested the existence of not only Pd adsorption, but also resorption and stabilization mechanisms.

Solute transport analysis using discrete fracture network model, 1

Nakajima, Makoto*; Atsumi, Hiroyuki*; Seno, Shoji*; Masumoto, Kazuhiko*; Kawabata, Junichi*; Kunimaru, Takanori; Onoe, Hironori; Saegusa, Hiromitsu; Hayano, Akira; Watanabe, Kunio*

no journal, , 

Solute transport conceptual models for crystalline rock environment is developed in the Mizunami Underground Research Laboratory (MIU) project conducted by Japan Atomic Energy Agency (JAEA) in order to construct scientific and technological basis for geological disposal of High-level Radioactive Waste (HLW). In this study, discrete fracture network model is developed using channel network to establish hydro-geological model and analyze factors in the solute transport behavior.

Development of recovery process of platinum-group metals from HLLW for stable production and volume reduction of homogeneous vitrified object, 8; Synthesis of ceramics support materials using some of the third period elements (Al and Si) and their sorption characteristics

Kobayashi, Hidekazu; Ayame, Yasuo; Ishidera, Takamitsu; Utsumi, Kazuo*; Takeshita, Kenji*; Onoe, Jun*; Nagayama, Sachiko*; Hasegawa, Yoshio*; Amamoto, Ippei

no journal, , 

no abstracts in English

Study on characterization of mass transportation using discrete fracture network model, 2; Model development taking into account consistency among geological and hydrogeological parameters

Masumoto, Kazuhiko*; Atsumi, Hiroyuki*; Iwano, Keita*; Nakajima, Makoto*; Seno, Shoji*; Kawabata, Junichi*; Saegusa, Hiromitsu; Onoe, Hironori; Sawada, Atsushi

no journal, , 

no abstracts in English