Selective separation of Am(III) from Ln(III) with a novel synergistic extraction system, N,N,N',N'-tetrakis(2-methylpyridyl)ethylenediamine (TPEN) and carboxylic acid in 1-octanol

Mirvaliev, R.*; Watanabe, Masayuki; Matsumura, Tatsuro; Tachimori, Shoichi*; Takeshita, Kenji*

Journal of Nuclear Science and Technology, 41(11), p.1122 - 1124, 2004/11

https://doi.org/10.3327/jnst.41.1122

Transmutation is a technology aimed to reduce HLW from reprocessing process. Minor actinides in the HLW will be converted to short-lived nuclides. However, lanthanides in HLW adversely affects on the efficiency of the transmutation. It is well known that separating An(III) and Ln(III) is very difficult because of their similarity of chemical properties. Therefore, the separation is one of the essential subjects to establish the transmutation technology. Considerable efforts have been devoted to the development of new extractants for the separation. N,N,N',N'-tetrakis(2-methylpyridyl)ethylenediamine (TPEN) demonstrates 100-fold preference for Am(III) over Ln(III) between stability constants with the ions in the aqueous phase. We have reported that Am(III) was selectively extracted from the aqueous phase containing Ln(III) by TPEN in nitrobenzene system and synergistic system with TPEN and D2EHPA in octanol. This work presents our recent results that Am(III) is separated from Eu(III) by a synergistic extraction system with TPEN and decanoic acid diluted with 1-octanol.

Extraction of Am(III) and Lanthanide(III) ions from HNO solutions using -dimethyl--diphenylpyridine-2,6-dicarboxyamide

Shimada, Asako; Yaita, Tsuyoshi; Narita, Hirokazu; Tachimori, Shoichi; Kimura, Takaumi; Okuno, Kenji*;

Solvent Extraction Research and Development, Japan, 11, p.1 - 10, 2004/04

The distribution ratio () of Am(III) and lighter Ln(III) in the extraction with -dimethyl--diphenylpyridine-2,6-dicarboxyamide(DMDPhPDA) from HNO solutions were determined. The D's increased with an increase of HNO concentration. Additionally, separation of Am(III) from Ln(III) were confirmed for all the HNO concentration range (S.F.=(D/D)). From 4 M HNO solution with 0.5 M DMDPhPDA CHCl solution, the 's of Am(III), Eu(III) and Nd(III) were 1.3, 0.25 and 0.24, respectively. This result suggests that Am(III) can be separated from Eu and Nd in the higher HNO concentration region than that has been reported so far. These 's value and the S.F. were reproduced in the extraction from the metal concentration range from 10 M order to 10 M.

Photoluminescence and Raman studies of curium and americium complexes of 6-methyl 2-(2-pyridyl)- benzimidazole; Evidence for an efficient intramolecular energy transfer

Assefa, Z.*; Yaita, Tsuyoshi; Haire, R. G.*; Tachimori, Shoichi

Inorganic Chemistry, 42(23), p.7375 - 7377, 2003/11

https://doi.org/10.1021/ic034759y

The 6-methyl- 2-(2-pyridyl)-benzimidazole (biz) ligand coordinates with the actinide species in solution, and the complexes display efficient intra-molecular energy-transfer processes. The energy transfer in the Cm(III):biz system proceeds in a non-radiative mode, whereas a radiative mode is the principal mechanism in the Am(III)-biz system.

Solvent extraction of alkaline earth metal ions by diglycolic amides from nitric acid solutions

Tachimori, Shoichi; Suzuki, Shinichi; Sasaki, Yuji; Apichaibukol, A.

Solvent Extraction and Ion Exchange, 21(5), p.707 - 715, 2003/09

https://doi.org/10.1081/SEI-120024552

no abstracts in English

Extraction of europium(III) into W/O microemulsion containing aerosol OT and a bulky diamide, 1; Cooperative effect

Suzuki, Hideya*; Naganawa, Hirochika; Tachimori, Shoichi

Solvent Extraction and Ion Exchange, 21(4), p.527 - 546, 2003/03

https://doi.org/10.1081/SEI-120022519

no abstracts in English

An Innovative chemical separation process (ARTIST) for treatment of spent nuclear fuel

Sasaki, Yuji; Suzuki, Shinichi; Tachimori, Shoichi*; Kimura, Takaumi

Proceedings of GLOBAL2003 Atoms for Prosperity; Updating Eisenhower's Global Vision for Nuclear Energy (CD-ROM), 4 Pages, 2003/00

no abstracts in English

Studies on actinide separation process from high-level liquid waste (Joint research)

Morita, Yasuji; Tachimori, Shoichi; Koma, Yoshikazu*; Aoshima, Atsushi*

JAERI-Research 2002-017, 20 Pages, 2002/08

JAERI-Research-2002-017.pdf:1.32MB

The present report describes the results of a joint study between Japan Nuclear Cycle Development Institute (JNC) and Japan Atomic Energy Research Institute (JAERI) on actinide separation process from high-level liquid waste. The purpose of the joint study is to point out common subjects in process development by an overall evaluation of each actinide separation process: TRUEX/SETFICS Process studied in JNC and DIDPA Extraction Process studied in JAERI. The result of the evaluation showed that both processes have common subjects to be studied in sub-processes such as treatment step for spent solvent or DTPA waste solution and solvent washing step for recycling, although the main process is different from each other. It is necessary to develop the sub-processes and to test the whole process including the sub-processes. Two essential requirements: the cost reduction and the minimization of secondary wastes, are very important in future research and development for more rational and effective actinide separation process.

Extraction of actinides(III), (IV), (V), (VI) and lanthanides(III) by structurally tailored diamides

Sasaki, Yuji; Tachimori, Shoichi

Solvent Extraction and Ion Exchange, 20(1), p.21 - 34, 2002/01

https://doi.org/10.1081/SEI-100108822

no abstracts in English

ARTIST process; A Novel chemical process for treatment of spent nuclear fuel

Tachimori, Shoichi

JAERI-Research 2001-048, 23 Pages, 2001/10

JAERI-Research-2001-048.pdf:1.88MB

A new chemical process, ARTIST process, is proposed for the treatment of spent nuclear fuel. The main concept of the ARTIST process is to recover and stock all actinides (Ans) in two groups, uranium (U) and a mixture of transuranics (TRU), to preserve their resource value and to dispose solely fission products (FPs). The process composed of two main steps, an U exclusive isolation and a total recovery of TRU; which copes with the nuclear non-proliferation measures, and additionally Pu separation process and soft N-donor process if requested, and optionally processes for separation of long-lived FPs. These An products: U-product and TRU-product, are to be solidified by calcination and allowed to the interim stockpile for future utilization. These separations are achieved by use of amidic extractants in accord with the CHON principle. The technical feasibility of the ARTIST process was explained by the performance of both the branched-alkyl monoamides the diglycolic amide (TODGA) in thorough extraction of all TRU by tridentate fashon.

The Effect of hydrophobic picrate on the extraction and separation of lanthanides(III) with carbamoylmethylene phosphine oxide

Naganawa, Hirochika; Suzuki, Hideya; Tachimori, Shoichi; Nasu, Akinobu*; Sekine, Tatsuya*

Physical Chemistry Chemical Physics, 3(12), p.2509 - 2517, 2001/06

https://doi.org/10.1039/b100073j

no abstracts in English