Chuanbo Li

Kinetics of reductive stripping of Np(VI) by acetohydroxamic acid from 30%TBP/kerosene to nitrate medium using a high-speedstirred cell

Abstract The kinetics of reductive stripping of Np(VI) by Acetohydroxamic Acid from 30%TBP/kerosene was investigated using a high-speed stirred cell designed by ourselves. The phase separator for sampling was simple and powerful. The interfacial areas of different stirring speeds were determined by microphotograph method at 21u2009℃ before the experiments. The effects of the different parameters as well as temperature were investigated systemically. The results showed that, at 21u2009℃ the rate equation is −u2009d[Np(VI)]/dtu2009=u2009k(S/V)[Np(VI)]0.78[AHA]0.46[HNO3]−0.20u2009−u2009k′(S/V)[Np(V)]2.87, where ku2009=u2009(8.7u2009±u20090.7)u2009×u200910−7u202f(mol/L)–0.04mu2009s–1, k′u2009=u20091.1u2009±u20090.2u202f(mol/L)–2.87u2009mu2009s–1, as c[HNO3]u2009<=u20091.0u2009mol/L, −u2009d[Np(VI)]/dtu2009=u2009k(S/V)[Np(VI)]0.78[AHA]0.46[HNO3]−1.42u2009−u2009k′(S/V)[Np(V)]2.87, where ku2009=u2009(3.2u2009±u20090.3)u2009×u200910−7u202f(mol/L)1.18u2009mu2009s–1, k′u2009=u20091.1u2009±u20090.2(mol/L)–2.87u2009mu2009s–1 as c[HNO3]u2009>=u20091.0u2009mol/L, and S is the interfacial area, V the organic phase volume. The reductive stripping process is controlled by chemical reactions (kinetics regime) taking place at the interface. The apparent activation energy is 13.5u2009±u20090.2u202fkJ/mol.

Study on the technology of U-Pu Co-stripping process for reprocessing spent fuel of fast reactor

Abstract To develop an aqueous reprocessing process for spent fuel of fast reactor, a counter current experiment (U-Pu co-stripping) based on a simplified PUREX process was carried out with 30%TBP/Kerosene solution containing U, Pu and HNO3. The experiment was done in a 16-stage miniature centrifugal contactor. The stripping percentage of U was 99.99%, Pu 99.94%. U stripping mainly took place in X1-feeding stage (11.00u2009mol/L HNO3 feeding stage) to the 16th one, while Pu stripping mainly took place in the first stage to the X1-feeding stage. And a simple method was presented to calculate cU/X1−feeding stage, Org when the X1-feeding stage number is more than 7 and the stripping percentage of U from the X1-feeding stage is more than 99.9% through the rear stages stripping. The calculation results by this method were validated by Computer Simulation when only changing U concentrations in feed solution from 40.0u2009g/L to 90.0u2009g/L or only changing the X1-feeding stage from the 7th stage to the 11th one. Finally the optimized technology was given.

Electrolytic partitioning of uranium and plutonium based on a new type of electrolytic mixer-settler

Summary The design of a new type of electroreduction mixer-settler for the partitioning of uranium and plutonium during the Purex process, which is featured with E-shaped cathodes and U-shaped anodes in settling chamber, is described and the operational results achieved using this equipment are presented. The results show that this new type of mixer-settler has excellent separation performances. The flow rate of organic feed solution is 3 mL/min and the flow ratio of feed solution (1BF) to aqueous back extraction stream (1BX) and to organic wash stream (1BS) is 4/1/1. For an organic feed of 84 g/L uranium and 1.40 ⁓ 2.64 g/L plutonium, both the separation factor of plutonium from uranium and that of uranium from plutonium are apparently higher than 104

Efficient uranous nitrate production using membrane electrolysis

Electrochemical reduction of uranyl nitrate is a green, simple way to make uranous ion. In order to improve the ratio of uranous ion to the total uranium and maintain high current efficiency, an electrolyser with very thin cathodic and anodic compartment, which were separated by a cation exchange membrane, was setup, and its performance was tested. The effects of various parameters on the reduction were also evaluated. The results show that the apparatus is quite positive. It runs well with 120xa0mA/cm2 current density (72xa0cm2 cathode, constant current batch operation). U(IV) yield can achieve 93.1xa0% (500xa0mL feed, total uranium 199xa0g/L) after 180xa0min electrolysis. It was also shown that when U(IV) yield was below 80xa0%, very high current efficiency was maintained, and there was almost a linear relationship between uranous ion yield and electrolysis time; under the range of experimental conditions, the concentration of uranyl nitrate, hydrazine, and nitric acid had little effect on the reduction.