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Journal Articles

Design of microchannel suitable for packing with anion exchange resins; Uranium separation from seawater containing a large amount of cesium

Ouchi, Kazuki; Tsukahara, Takehiko*; Brandt, A.*; Muto, Yuki*; Nabatame, Nozomi*; Kitatsuji, Yoshihiro

Analytical Sciences, 37(12), p.1789 - 1794, 2021/12

We attempted to scale down a separation process of uranium (U) using the microchip column loaded with anion exchange resin to develop safety and waste-reducing separation technique. The ideal separation performance of U was obtained by the properly design of a microchannel. The concentration of U in seawater as a real-world sample could be quantified with the prepared microchip column. It indicates that the microchip column is sufficiently practical. Compared to separation of U with a general column, the column size was successfully scaled down to 1/5000.

Journal Articles

Application of turbidity measurement for evaluation of two-phase separation in ,-dialkylamides-nitric acid systems

Tsutsui, Nao; Ban, Yasutoshi; Hakamatsuka, Yasuyuki; Urabe, Shunichi; Matsumura, Tatsuro

Proceedings of 21st International Conference & Exhibition; Nuclear Fuel Cycle for a Low-Carbon Future (GLOBAL 2015) (USB Flash Drive), p.1153 - 1157, 2015/09

,-Dialkylamides are promising alternative extractants to tri--butyl phosphate in the reprocessing of spent nuclear fuels, but the two-phase separation between their organic and aqueous phases has not been evaluated quantitatively. ,-Di(2-ethylhexyl)-2,2-dimethylpropanamide (DEHDMPA) in -dodecane were agitated with uranyl nitrate-containing nitric acid, and their turbidities and their uranium distribution ratios were measured with respect to the time for the quantitative evaluation. Increasing DEHDMPA, uranium, and nitric acid concentrations enhanced turbidities. Although turbidities decreased with respect to the time, uranium distribution ratios slightly changed, indicating the observed turbidities did not affect these uranium distribution ratios significantly. Therefore, DEHDMPA may act as suitable extractant for uranium in nitric acid from two-phase separation viewpoint, and turbidity may be an indicator for extractant performance evaluation.

Journal Articles

Determination of uranium and rare-earth metals separation coefficients in LiCl-KCl melt by electrochemical transient techniques

Kuznetsov, S. A.*; Hayashi, Hirokazu; Minato, Kazuo; Gaune-Escard, M.*

Journal of Nuclear Materials, 344(1-3), p.169 - 172, 2005/09

https://doi.org/10.1016/j.jnucmat.2005.04.037

Times Cited Count：24 Percentile：84.12(Materials Science, Multidisciplinary)

The knowledge of separation coefficients of actinides and rare-earth metals is important for developing pyrometallurgical process of spent nuclear fuel. Electrochemical experiments were carried out at 723-823 K to estimate separation coefficients in LiCl-KCl eutectic melt containing uranium and lanthanum trichlorides. Uranium and lanthanum separation coefficients is calcurated with the voltammetric peak potentials of U (III) and La (III), their concentration in the melt and kinetic parameters for U(III) discharge such as diffusion coefficients, and standard rate constants of charge transfer. The diffusion coefficients of U (III) were determined by some electrochemical measurements. The standard rate constants of charge transfer for electroreduction of uranium U(III) +3e $^{-}$ =U were calculated by impedance spectroscopy method.

Journal Articles

Behavior of simulated spent fuel in subcritical water

Mineo, Hideaki; Suzuki, Tadashi; Morita, Yasuji

Proceedings of 2nd International Symposium on Supercritical Fluid Technology for Energy and Environment Applications (Super Green 2003), p.334 - 338, 2003/00

Behavior of spent nuclear fuel in subcritical water was investigated to look at the feasibility of fission-products (FPs) separation without organic solvent. The study employed unirradiated UO $_{2}$ particles simulating spent fuel burned up to 45,000MWdt $^{-1}$ , which includes FP elements in oxide form: Sr, Zr, Mo, Ru, Rh, Pd, Ag, Ba, La, Ce, Pr, Nd and Sm. Also, alloy particles consisted of Mo, Ru, Rh and Pd were prepared to simulate the metallic phase of FP. 12.728 g of the fuel and 52 mg of the alloy were placed in a 10 ml pressure vessel, where subcritical water was fed. The temperature was 523, 573, 623 and 663K, while the pressure was kept at 29MPa. Dissolved fraction decreased with elevating temperature. It was found that more than 5% of Ba, Mo and Pr were respectively dissolved. The dissolved fraction of Sr and Rh were about 1%, and about 0.3% for Zr. La, Ce, Nd and Sm, indicated almost the same result as U, which was about 0.1%. It was suggested that the subcritical water could separate portion of FP. Further study would be carried out with smaller-sized fuel.

JAEA Reports

Transportation of significant metals recovered in real sea experiment of adsorbents

Takeda, Hayato*; Onuma, Kenji*; Tamada, Masao; Kasai, Noboru; Katakai, Akio; Hasegawa, Shin; Seko, Noriaki; Kawabata, Yukiya*; Sugo, Takanobu

JAERI-Tech 2001-062, 66 Pages, 2001/10

JAERI-Tech-2001-062.pdf:5.5MB

Real sea experiment for the recovery of significant metals such as uranium and vanadium has been carried out at the offing of Mutsu establishment to evaluate the adsorption performance of adsorbent synthesized by radiation-induced graft-polymerization. After elution of uranium and vanadium from the adsorbent, their metals were adsorbed onto the conventional chelate resin. This chelate resin in a plastic column was further put in a cylindrical stainless transport container. The container was transported to the facility for separation and purification by a truck for the exclusive loading. The maximum concentration is 60 Bq/g when the uranium is adsorbed on the chelate resin. Transportation of recovered metals can be treated as general substance since these amount and concentration are out of legal control. However, the recovered metals were transported in conformity to L type transportation as a voluntary regulation. The strength analysis of the container was equal to the safety level of IP-2 type which is higher transportation grade than L type .

Journal Articles