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Journal Articles

Re-evaluation of radiation-energy transfer to an extraction solvent in a minor-actinide-separation process based on consideration of radiation permeability

Toigawa, Tomohiro; Tsubata, Yasuhiro; Kai, Takeshi; Furuta, Takuya; Kumagai, Yuta; Matsumura, Tatsuro

Solvent Extraction and Ion Exchange, 39(1), p.74 - 89, 2021/00

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

Absorbed-dose estimation is essential for evaluation of the radiation feasibility of minor-actinide-separation processes. We propose a dose-evaluation method based on radiation permeability, with comparisons of heterogeneous structures seen in the solvent-extraction process, such as emulsions forming in the mixture of the organic and aqueous phases. A demonstration of radiation-energy-transfer simulation is performed with a focus on the minor-actinide-recovery process from high-level liquid waste with the aid of the Monte Carlo radiation-transport code PHITS. The simulation results indicate that the dose absorbed by the extraction solvent from alpha ray depends upon the emulsion structure, and that from beta and gamma ray depends upon the mixer-settler-apparatus size. Non-negligible contributions of well-permeable gamma rays were indicated in terms of the plant operation of the minor-actinide-separation process.

Journal Articles

Study on the mechanism of radiolytic degradation of an extractant for minor actinides separation

Toigawa, Tomohiro; Murayama, Rin*; Kumagai, Yuta; Yamashita, Shinichi*; Suzuki, Hideya; Ban, Yasutoshi; Matsumura, Tatsuro

UTNL-R-0501, p.24 - 25, 2020/12

This report summarizes the results obtained in FY2019 at Electron Linac Facility of University of Tokyo. The radiolysis process of a diglycolamide extractant, which is expected to be used in the separation process of minor actinides (MA), in dodecane and octanol solutions was investigated by pulse radiolysis. As a result, it was suggested that by adding alcohol, the decomposition process of the diglycolamide extractant was different from the decomposition processes in the single solvent of dodecane considered that the decomposition occurred via a radical cation species of the extractant.

Journal Articles

Extractions and spectroscopic studies of various metals with Diglycolamide-Type Tridentate Ligands

Sasaki, Yuji; Saeki, Morihisa*; Yoshizuka, Kazuharu*

Solvent Extraction Research and Development, Japan, 26(1), p.21 - 34, 2019/06

 Times Cited Count:5 Percentile:43.69(Chemistry, Multidisciplinary)

Three tridentate extractants and three masking reagents including O, N, and S donors have been developed and their properties are compared and discussed. The extractants are termed as tetraoctyl-diglycolamide (TODGA), methylimino-dioctylacetamide (MIDOA) and tetraoctyl-thiodiglycolamide (TDGA(C8)) and masking agents have the same central frame but with short alkyl chain. The results of the present study indicate that TODGA can extract mainly hard acid metals belonging groups 2-4,13-15 in periodic table, MIDOA can extract soft acid metals and oxyanions (groups 5-10, 16), and TDGA can extract soft acid metals (groups 10-11). Some spectrophotometric studies (UV, IR, and NMR) indicate the stoichiometry and effect of donor atoms for metal-complexation. The Hf values, the heat generation during complex formation, obtained by chemical calculation by DFT theory show the reverse-correlation with their extraction ability.

Journal Articles

Mutual separation of trivalent lanthanide and actinides by hydrophilic and lipophilic multidentate diamides

Sasaki, Yuji; Morita, Keisuke

Progress in Nuclear Science and Technology (Internet), 5, p.27 - 32, 2018/12

no abstracts in English

Journal Articles

Metal extractions by diglycolamide-type tridentate ligands

Sasaki, Yuji; Morita, Keisuke; Saeki, Morihisa*; Hisamatsu, Shugo*; Yoshizuka, Kazuharu*

Proceedings of 21st International Solvent Extraction Conference (ISEC 2017) (Internet), p.131 - 134, 2017/11

Three tridentate extractants including soft and hard donor has been developed and examined. The extractants are termed as $$N, N, N', N'$$-tetraoctyl-diglycolamide (TODGA), methylimino-$$N, N'$$-dioctylacetamide (MIDOA) and $$N, N, N', N'$$-tetraoctyl-thiodiglycolamide (TDGA). The results of the present study show that TODGA can extract completely lanthanides and actinides, MIDOA can extract palladium, technetium, and rhenium, and TDGA can extract palladium, silver, and gold. We can compare the distribution ratios of these metals by TODGA, MIDOA, and TDGA. These results can be supported by some spectrometric studies, i.e., IR, NMR and UV, and calculations of metal complexes.

Journal Articles

Reduction and resource recycling of high-level radioactive wastes through nuclear transmutation; Isolation techniques of Pd, Zr, Se and Cs in simulated high level radioactive waste using solvent extraction

Sasaki, Yuji; Morita, Keisuke; Ito, Keisuke; Suzuki, Shinichi; Shiwaku, Hideaki; Takahashi, Yuya*; Kaneko, Masaaki*; Omori, Takashi*; Asano, Kazuhito*

Proceedings of International Nuclear Fuel Cycle Conference (GLOBAL 2017) (USB Flash Drive), 4 Pages, 2017/09

no abstracts in English

Journal Articles

Precious metal extraction by N,N,N',N'-tetraoctyl-thiodiglycolamide and its comparison with N,N,N',N'-tetraoctyl-diglycolamide and methylimino-N,N'-dioctylacetamide

Sasaki, Yuji; Morita, Keisuke; Saeki, Morihisa*; Hisamatsu, Shugo; Yoshizuka, Kazuharu*

Hydrometallurgy, 169, p.576 - 584, 2017/05

 Times Cited Count:10 Percentile:59.14(Metallurgy & Metallurgical Engineering)

The novel tridentate extractant including soft donor has developed and examined. The extractant, tetraoctyl-thiodiglycolamide (TDGA), is analogous structure to tetraoctyl-diglycolamide (TODGA) and methylimino-dioctylacetamide (MIDOA), but with sulfur donor instead of ether oxygen or nitrogen atoms of TODGA or MIDOA. From the present work, TDGA can extract silver, palladium, gold, and mercury from acidic solutions to n-dodecane. In addition to these results, the distribution ratios of hard and soft acid metals by using TDGA, TODGA, and MIDOA are compared, where the metal-complexations with each donor atom are investigated. 1H-NMR and IR studies for the metal-TDGA complexes indicate the role on donor atoms, S and N, of TDGA.

Journal Articles

Solvent extraction of metal ions using a new extractant, biuret(C8)

Sasaki, Yuji; Yoshimitsu, Ryo*; Nishihama, Shohei*; Shimbori, Yuma*; Shiroishi, Hidenobu*

Separation Science and Technology, 52(7), p.1186 - 1192, 2017/03

 Times Cited Count:2 Percentile:12.88(Chemistry, Multidisciplinary)

The new extractant, biuret(C8), is synthesized and tested for the solvent extraction of hard acid metals like actinides and soft acid metals. This compound has the similar central frame to malonamide but with 2-NH introduced into the central frame, then both amidic oxygen and nitrogen atoms may bond with metals. From the present work, not only hard acid metals, but also soft acid metals can be extracted by biuret(C8) from nitric or perchloric acids to n-dodecane. The extractability for biuret(C8) is compared with other representative extractants, malonamide, TODGA and MIDOA. It is clear that the distribution ratio(D) of U and Pu by biuret(C8) is similar to those for malonamide, but with lower values than those for TODGA and MIDOA, and D for soft acid metals and oxonium anions show higher values than those for TODGA and malonamide and lower than those for MIDOA.

Journal Articles

Effect of surface treatment on adsorption and desorption behavior of impregnated adsorbent for extraction chromatography

Nagoshi, Kohei*; Arai, Tsuyoshi*; Watanabe, So; Sano, Yuichi; Takeuchi, Masayuki; Sato, Mutsumi*; Oikawa, Hiroshi*

Nihon Ion Kokan Gakkai-Shi, 28(1), p.11 - 18, 2017/01

no abstracts in English

Journal Articles

Extraction capacity of diglycolamide derivatives for Ca(II), Nd(III) and Zr(IV) from nitric acid to $$n$$-dodecane containing a solvent modifier

Sasaki, Yuji; Zhu, Z.-X.; Sugo, Yumi; Suzuki, Hideya*; Kimura, Takaumi

Analytical Sciences, 21(10), p.1171 - 1175, 2005/10

 Times Cited Count:26 Percentile:60.4(Chemistry, Analytical)

In order to evaluate the extraction property of the new extractants, diglycolamide(DGA) compounds, we investigated the maximum extraction of di-, tri-, and tetravalent metal ions using the system of nitric acid and n-dodecane. Limits of metal concentration (LOC) for Ca(II), Nd(III) and Zr(IV) influence strongly on HNO$$_{3}$$ and the extractant concentration. On the purpose to raise the LOC value, we employed the modifier of solvent, N,N-dihexyl-octanamide(DHOA) and DGA with the long alkyl chain, and examined. It is evident that LOC increases with DHOA concentration in n-dodecane and the length of alkyl chain attached with N atom of DGA. The stoichiometric values of LOC(Zr) estimated from the extraction reaction is obtained by using the extraction condition: tetraoctyl-DGA/ 1M DHOA+n-dodecane and 3M HNO$$_{3}$$.

Journal Articles

Novel compounds, Diglycolamides (DGA), for extraction of various metal ions from nitric acid to n-dodecane

Sasaki, Yuji; Zhu, Z.-X.; Sugo, Yumi; Kimura, Takaumi

Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 5 Pages, 2005/10

The extraction of metals by N,N,N',N'-tetraoctyl-diglycolamide (TODGA) from nitric acid to n-dodecane was investigated. From the measurement of distribution ratios, it was obvious that Ca (ionic radius: 100pm), trivalent and tetravalent ions with ionic radii of 87-113 and 83-94 pm are highly extractable by TODGA. In order to evaluate the extraction capacity in extraction solvent using DGA compounds, we measured the limits of metal concentration (LOC) for Ca(II), Nd(III) and Zr(IV). For the purpose to enhance the LOC value, we examined the modifier of solvent, N,N-dihexyl-octanamide(DHOA) and DGA with longer alkyl chain. It is evident that LOC is increased with DHOA concentration and the length of alkyl chain attached to N atom of DGA.

Journal Articles

Radiolysis of TODGA and its effect on extraction of actinide ions

Sugo, Yumi; Sasaki, Yuji; Kimura, Takaumi; Sekine, Tsutomu*; Kudo, Hiroshi*

Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 4 Pages, 2005/10

no abstracts in English

Journal Articles

A method for the determination of extraction capacity and its application to $$N,N,N',N'$$-tetraalkylderivatives of diglycolamide-monoamide/n-dodecane media

Sasaki, Yuji; Sugo, Yumi; Suzuki, Shinichi; Kimura, Takaumi

Analytica Chimica Acta, 543(1-2), p.31 - 37, 2005/07

 Times Cited Count:96 Percentile:93.83(Chemistry, Analytical)

The detailed study of extraction capacity of diglycolamide (DGA) with and without DHOA, N,N'-dihexyloctanamide as a modifier, was performed by using the novel analytical method for the determination of the limit of metal concentration in the organic phase (LOC). The effect on modifier was studied and it is confirmed that LOC increases with DHOA concentration. It is noteworthy that LOC reaches to the stoichiometric value, which is obtained by the extraction reaction, by using 0.1M TODGA mixed with more than 0.5M DHOA into n-dodecane. Without modifier, relation of the different DGA compounds with LOC was investigated, and it is clear that LOC using N,N,N',N'-tetradodecyl-diglycolamide (TDdDGA), whose extractant can suppress the third phase, reaches to the stoichiometric value. From this work, it is obvious that the application of the condition without the third phase formation, e.g., enough concentration of modifier coexisted and DGA with long alkyl chain, is important to attain the stochiometric LOC value.

Journal Articles

Cumulative study on solvent extraction of elements by ${it N,N,N',N'}$-tetraoctyl-3-oxapentanediamide (TODGA) from nitric acid into ${it n}$-dodecane

Zhu, Z.-X.; Sasaki, Yuji; Suzuki, Hideya*; Suzuki, Shinichi; Kimura, Takaumi

Analytica Chimica Acta, 527(2), p.163 - 168, 2004/12

 Times Cited Count:229 Percentile:98.89(Chemistry, Analytical)

The extraction of 75 elements by ${it N,N,N',N'}$-tetraoctyl-3-oxapentanediamide (TODGA) from nitric acid to ${it n}$-dodecane was investigated and discussed concerning distribution ratios (D) of metal ions and their ionic radii. The extractability for elements depends strongly on their oxidation state. Monovalent and pentavalent ions were not extractable. In divalent metal extraction, Ca(II) (ionic radius: 100 pm) showed the highest D value and the D decreased with increase or decrease of the ionic radius. Tri- and tetravalent ions with ionic radii of 87-113 pm and 83-94 pm, respectively, showed the D over 1000, and the extracted chemical forms were determined to be M(TODGA)$$_{3}$$(NO$$_{3}$$)$$_{{it n}}$$ or M(TODGA)$$_{4}$$(NO$$_{3}$$)$$_{{it n}}$$ (${it n}$=3 or 4). The oxonium ions with higher oxidation states than tetravalent one forms the complicated metal-complex with TODGA, and the number of TODGA associated in those extraction reactions was confirmed to be 2 at most.

Journal Articles

Effect of DTPA on the extractions of Actinides(III) and Lanthanides(III) from nitrate solution into TODGA/${it n}$-dodecane

Apichaibukol, A.; Sasaki, Yuji; Morita, Yasuji

Solvent Extraction and Ion Exchange, 22(6), p.997 - 1011, 2004/12

 Times Cited Count:35 Percentile:69.24(Chemistry, Multidisciplinary)

no abstracts in English

Journal Articles

Extraction and separation of Am(III) and Sr(II) by N,N,N',N'-tetraoctyl-3-oxapentanediamide (TODGA)

Suzuki, Hideya*; Sasaki, Yuji; Sugo, Yumi; Apichaibukol, A.; Kimura, Takaumi

Radiochimica Acta, 92(8), p.463 - 466, 2004/08

 Times Cited Count:80 Percentile:97.75(Chemistry, Inorganic & Nuclear)

The promising extractant for the partitioning of HLLW, TODGA, was used and investigated for the extraction of Sr(II) and separation from Am(III). Both metal ions can be extracted by TODGA based on the extraction reaction accompanying the neutral HNO$$_{3}$$ as well as the counter anion, NO$$_{3}$$$$^{-}$$. The mixture of TODGA and monoamide can reduce the distribution ratio of Sr(II), compared to the D(Sr) without monoamide, this solvent may extract only Am(III) with holding Sr(II) in the aqueous phase. After extraction of An by TODGA and monoamide, Sr(II) remaining in HLLW can be extracted by using enough high concentration of TODGA at the next step. Because of its high D value, Sr(II) can be coextracted with An by TODGA. It was observed that D(Sr) decrease with an increase of HNO$$_{3}$$ from 3M to 6M HNO$$_{3}$$ at the same TODGA concentration, while Am(III) has still high D values at least until 6M HNO$$_{3}$$. By using 6M HNO$$_{3}$$ of aqueous phase, An and Sr(II) can be separated after coextraction.

Journal Articles

Development of ARTIST process, extraction and separation of actinides and fission products by TODGA

Sasaki, Yuji; Sugo, Yumi; Suzuki, Hideya*; Kimura, Takaumi

Proceedings of International Conference ATALANTE 2004 Advances for Future Nuclear Fuel Cycles (CD-ROM), 4 Pages, 2004/06

no abstracts in English

Journal Articles

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

 Times Cited Count:43 Percentile:74.56(Chemistry, Multidisciplinary)

no abstracts in English

Journal Articles

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

Journal Articles

A Process of spent nuclear fuel treatment with the interim storage of TRU by use of amidic extractants

Tachimori, Shoichi; Suzuki, Shinichi; Sasaki, Yuji

Nihon Genshiryoku Gakkai-Shi, 43(12), p.1235 - 1241, 2001/12

 Times Cited Count:25 Percentile:85.59(Nuclear Science & Technology)

no abstracts in English

32 (Records 1-20 displayed on this page)