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The distribution coefficients of uranium, nitric acid and 8 elements simulating fission products were obtained from the concentrated aqueous solutions of nitrates, whose nitrate ion concentrations were 4–15 mol dm−3. The relationships among the distribution coefficient of uranium, the nitrate ion concentration in the aqueous phase, and the concentration of tri-n-butylphosphate uncombined with nitrates in the organic phase were obtained from the data.

A femtosecond laser is a type of ultrashort-pulse laser. Femtosecond laser irradiation induces high-pressure plasma and shock waves at the surface of a target. Under some irradiation conditions, such shock waves are enough to deform the target plastically. Laser peen forming is a type of sheet metal forming using this deformation by shock waves. The author adopted laser peen forming using femtosecond laser for thin-sheet-metal bending. Generally, shock waves induced in air are much smaller than those induced in water, and thus; are unfavorable for plastic deformation. However, the shock waves induced by a femtosecond laser were enough to bend a thin sheet metal even in air. Elastic pre-bending was adopted during the process. Bending angle was increased by applying pre-bending. The effects of laser irradiation conditions on bending efficiency were investigated. The large spot diameter and high fluence improved bending efficiency.

A femtosecond laser is a type of ultrashort pulse laser. A focused femtosecond laser pulse induces high-pressure plasma and a shock wave at the surface of a target. In some cases, this shock wave is enough to deform the target plastically. Laser peen forming is a type of sheet metal forming using this deformation by shock wave. The authors adopted laser peen forming for thin-sheet-metal bending. A piece of sheet metal was bent by femtosecond laser scanning. An investigation was conducted into the influences of irradiation conditions and prebending on forming properties. When irradiating in air, bending angles increased with fluence. However, when irradiating in water, the exceedingly large fluence decreased the bending angles. The bending angles were increased by applying prebending during the irradiation. Selection of appropriate prebending directions and irradiation conditions allowed the bending direction to be controlled. Several pieces of sheet metal for springs were bent into various shapes that would be difficult to achieve using the usual press forming process.

The behavior of Cs in the U crystallization of an advanced aqueous reprocessing system was investigated. A beaker-scale U crystallization experiment was carried out with a certain simulated dissolver solution. Results show that the possibility of the generation of CsNO3, Cs2UO2(NO3)4 or Cs-FP complex salt is small. A precipitation experiment of Cs-U(IV) complex salts was also carried out with a nitrate solution of U(IV) and Cs. It was found that Cs2U(NO3)6 precipitates at an acidity higher than 5 mol dm−3. It is considered that Cs2Pu(NO3)6 precipitates can be generated in a U crystallization process under a specific solution condition.

1,3‐[(2,4‐Diethyl‐heptylethoxy)oxy]‐2,4‐crown‐6‐calix[4]arene (Calix[4]arene‐R14) is a supramolecular compound exhibiting Cs ion recognition in high level liquid waste (HLLW). To separate effectively Cs(I) from HLLW, a novel silica‐based Calix[4]arene‐R14 polymeric material (Calix[4]arene‐R14/SiO2‐P) was prepared. It was done through impregnating a mixture of Calix[4]arene‐R14 and tri‐n‐butyl phosphate (TBP), a molecular modifier, into the pores of macroporous SiO2‐P particles utilizing a vacuum sucking technique. The sorption of some typical fission product (FP) elements Na(I), K(I), Cs(I), Rb(I), Sr(II), and La(III) towards Calix[4]arene‐R14/SiO2‐P was investigated by examining the influence of contact time and the HNO3 concentration. It was found that with an increase in the HNO3 concentration from 1.0 M to 4.0, the sorption of Cs(I) towards Calix[4]arene‐R14/SiO2‐P increased quickly and then decreased with further increase of HNO3 concentration to 5.0 M. At the optimum HNO3 concentration of 4...

Using the advanced aqueous reprocessing system named NEXT process, actinides recovery was attempted by both a simplified solvent extraction process using TBP as an extractant for U, Pu and Np co-recovery and the SETFICS process for Am and Cm recovery from the raffinate. In U, Pu and Np co-recovery experiments a single cycle flow sheet was used under high nitric acid concentration in the feed solution or scrubbing solution. High nitric acid concentration in the feed solution aided Np oxidation not only in the feed solution, but also at the extraction section. This oxidation reaction accomplished Np extraction by TBP with U and Pu. Most of Np could be recovered into the product solution. In the SETFICS process, a TRUEX solvent of 0.2 mol/dm3 CMPO and 1.4 mol/dm3 TBP in n-dodecane was employed instead of 0.2 mol/dm3 CMPO and 1.0 mol/dm3 TBP in n-dodecane in order to increase the loading of metals. Instead of sodium nitrate, hydroxylamine nitrate was applied to this experimental flow sheet in accordance with ...

Hydrophobic cyclic polyether, decyl-l8-crown-6 (D18C6), is well known to have a selective uptake ability for strontium (II) . Calcium alginate microcapsule (MC) containing D 18C6 was fabricated for the efficient separation of strontium (II) from concentrated nitric acid solution. In this study, hybrid MCs containing D18C6 and sodium lauryl benzenesulfonate (Na-LBS) were prepared, and distribution coefficient, Kd, was improved to be over 80 cm3/g by using them. MCs were also prepared by using nitric acid and divalent metal ions, and the effect on Kdvalues was examined. The optimum condition was applied to the continuous column separation.

The resistance of a novel silica-based N,N,N′,N′- tetraoctyl-3-oxapentane-1,5-diamide (TODGA) polymeric adsorption material (TODGA/SiO 2 -P) against nitric acid, temperature and γ -irradiation had been investigated. The adsorption property of the treated TODGA/SiO 2 -P was evaluated by a 3 M HNO 3 solution containing 0.01 M Nd(III). It was found that both 3 and 0.01 M HNO 3 concentrations did not decrease the stability of TODGA/SiO 2 -P at 25°C. The quantity of TODGA leaked from TODGA/SiO 2 -P was equivalent to its solubility in the corresponding HNO 3 aqueous solution. The effect of 3 M HNO 3 on the leakage of TODGA at 80°C was significantly higher than that in 0.01 M HNO 3 as well as in all cases at 25°C. The amount of Nd(III) adsorbed towards the treated TODGA/SiO 2 -P was determined in the range of 0.143–0.148 mmol/g for the HNO 3 concentration effect and 0.142–0.0506 mmol/g for the temperature effect. γ -Irradiation showed a more noticeable destruction effect on TODGA/SiO 2 -P. The content of TODGA leaked increased with an increase in the γ -irradiation dose (ID) from 1.06 to 3.72 MGy in terms of the linear equation [TODGA]=794.5ID+84.0. The amount of Nd(III) adsorbed onto the irradiated TODGA/SiO 2 -P decreased rapidly from 0.134 to 0.0438 mmol/g, which was lower than 0.153 mmol/g, the adsorption of fresh TODGA/SiO 2 -P for Nd(III), according to the equation Q Nd(III) =−0.0301ID+0.160, showing that a large quantity of TODGA leaked from TODGA/SiO 2 -P. The adsorbed amount of Nd(III) decreased obviously in this order: the HNO 3 concentration effect, temperature effect and γ -irradiation.

The design study of an aqueous reprocessing system has been progressed for the feasibility study on commercialized fast reactor cycle systems in Japan. A simplified PUREX process, with the addition of a uranium crystallization step and a minor actinide (MA) recovery process was proposed as the NEXT process. For the simplified PUREX process and the SETFICS/TRUEX process for MA recovery, small-scale hot tests were conducted. The test results showed the decontamination factor (DF) of 105 for the U, Pu and Np product was a reasonable target for the simplified PUREX process. Concerning to the Am and Cm product, the DF of rare earth elements (REs) and the other fission products (FPs) were over 10 and over 102, respectively. For economical competitiveness, an aqueous reprocessing plant with the capacity of 200 tHM/yr cleared the target cost, while the plant with the capacity of 50tHM/yr did not clear it. For efficient utilization of resources, the calculated U and TRU recovery of both plants was over 99wt%. Usin...