低能耗熔盐电解金属锂电解槽的开发及研究

近年来,金属锂在全固态锂电池、铝锂合金制备中发挥着不可替代的价值,但金属锂生产成本仍然是生产企业需要解决的问题。因此,从降低能耗角度优化生产工艺及设备角度利用Solid Works三维建模电解槽结构,以及ANSYS仿真模拟软件对电解槽进行热场模拟及计算,得出最优设计方案。生产电解效率可达到91%,能耗在35 kWh/kg以下,抽氯和集锂装置可以自动运行,抽出氯气浓度90%,集锂效率可达到80%以上,且出锂量较为稳定。该设备可以更好的投入产业化生产,满足企业降低生产成本的需要,促进熔盐电解金属锂行业的发展。     

低分子量壳聚糖季铵盐的制备及抗菌性能研究

通过γ射线辐照壳聚糖降解,得到低分子量壳聚糖,并采用环氧丙基三甲基氯化铵对低分子量壳聚糖进行季铵化改性.制备了低分子量壳聚糖季铵盐,并测试其抗菌性.用傅立叶变换红外光谱(Fourier transform infrared spectroscopy,FT-IR)和核磁共振碳谱(13C Nuclear magnetic resonance,13C NMR)表征壳聚糖和壳聚糖季铵盐的结构,结果表明,经γ射线辐照过的壳聚糖,其季铵盐的取代度比未辐照的高,对大肠杆菌和金黄色葡萄球菌的抗菌效果也得到明显改善,γ射线辐照没有破坏壳聚糖的分子结构.     

Electrochemical Study on the Reduction Mechanism of Uranium Oxide in a LiCl-Li2O Molten Salt

By means of a linear sweep voltammetry, a cyclic voltammetry and a chronopotentiometry, the electrolytic reduction of uranium oxide has been studied to establish the reduction mechanisms, which are based on a simultaneous uranium oxide reduction and a Li₂O electrowinning, and the formation and electrolysis of lithium uranate. From the voltammograms, the reduction potentials of the uranium oxide and Li₂O were obtained. From the chronopotentiometries based on the results of the voltammograms, the uranium oxide was reduced to uranium metal through the reduction mechanisms showing a more than 99% conversion. For a verification of the reduction mechanisms feasibility, basic data on the electrolytic reduction of the uranium oxide was obtained from the experiments and the characteristics of the closed recycle of Li₂O were discussed.     

Electrochemical Reduction of (U,Pu)O2 in Molten LiCl and CaCl2 Electrolytes

The electrochemical reduction of UO₂-PuO₂ mixed oxides (MOX) was performed in molten LiCl at 923 K and CaCl₂ at 1,123 K to evaluate the behavior of the plutonium quantitatively and to define the optimum conditions for the electrochemical reduction of those materials.

In LiCl, excess deposition of lithium metal can be avoided and the MOX was smoothly reduced at ?0.65 V vs. Bi-35 mol% Li reference electrode. The reduction ratio calculated from the mass change of the samples taken during the electrochemical reduction and the ratio evaluated by gas-burette method were in good agreement. The cathodic current efficiency remained 30–50% mainly due to the deoxidation of tantalum cathode basket. Although dissolution of plutonium and americium into the electrolyte was found by the chemical analysis, the dissolved amount was negligible and had no immediate influence on the feasibility of the electrochemical reduction process.

In CaCl₂, reduction of the MOX occurred in whole range of the tested cathode potential (?0.15 V to ?0.40 V vs. Ca-Pb reference electrode). The cathodic current efficiency was around 30%. Although the MOX was completely reduced at ?0.25 V, the reduction was interrupted by formation of the surface barrier made of the reduced material and the vacancy between the reduced and the non-reduced areas at ?0:30 V. Plutonium and americium dissolved also into the CaCl₂ electrolyte to slightly higher concentrations than those observed in LiCl electrolyte. The analyses for the reduction products showed that the amount of those actinides lost from the cathode was much larger than that found in the electrolyte, probably due to the formation of mixed oxide precipitate.     

Isolation of 137Cs with Copper Ferrocyanide-Anion Exchange Resin

The adsorption and desorption of ¹³⁷Cs on copper ferrocyanide-anion exchange resin, prepared in the manner previously reported in this Journal in a Short Note, are presented in detail.

This resin can also be used for the concentration of the ¹³⁷Cs found in sea water. The nuclide is adsorbed effectively on the resin from water, hydrochloric acid below 4 M, and on nitric acid below 1M. After adsorpsion on the resin, ¹³⁷Cs is eluted easily with either nitric acid (>6M), ammonium water, or silver nitrate solution.

Adsorption on the resin is specific for ¹³⁷Cs, and the action is due entirely to the ferrocyanide moiety of the resin.

This method is more efficient than the co-precipitation method with copper ferrocyanide for the concentration of radiocesium from a large volume of sea water.     

Calculation of Symmetric Stretching Frequency in Molten BeF2 by Molecular Dynamics Method

The molecular dynamics method was applied to molten BeF₂, in which the pair potentials of the Born-Mayer-Huggins type were employed. The Fourier transform of the distances between a Be²⁺ ion and its nearest neighboring F^? ions averaged over total 12 Be²⁺ ions gave the frequency of about 175 cm^?1 as the symmetric stretching frequency which is in satisfactory agreement with 282 cm^?1 obtained with Raman spectroscopy.

The self-diffusion coefficients of Be²⁺ and F^? ions were estimated to be 2×l0^?10m²/sec and the internal energy was ?2,559 kJ/mol at 973 K.     

小型模块化熔盐快堆燃料管理初步分析

由于燃料随熔盐流动的特性以及可以进行在线添料与处理的特点,液态燃料熔盐堆的燃耗分析与燃料管理和传统固态燃料反应堆有很大不同,需要针对液态燃料熔盐堆的特点重新开发燃耗分析与管理程序。本文针对液态燃料熔盐堆的熔盐流动特性以及在线添料与处理功能,基于MCNP5和ORIGEN2.1燃耗耦合程序,开发了适用于液态燃料熔盐堆的燃料管理程序,并应用于一种小型模块化熔盐快堆的燃料管理和分析,对比分析了5种不同运行方案以及分批在线添料情况下,运行30年期间keff的变化情况及重要核素的演化情况。计算结果表明,采用不断调整添料率的连续在线添料运行方案和固定批量添料的运行方案,都可以让小型模块化熔盐快堆维持运行在一个较小的keff波动范围之内。开发的燃料管理程序适用于液态燃料熔盐堆的研究,同时可以为液态燃料熔盐堆的设计及燃耗管理和分析提供有价值的参考。     

The effect of corrosion product CrF3 on thermo-physical properties of FLiNaK

FLiNaK (LiF–NaF–KF: 46.5–11.5–42 mol %) is a promising candidate as the secondary loop coolant in molten salt reactor. The thermo-physical properties of pure FLiNaK and FLiNaK containing up to 6000 ppm (equivalent to mg/kg) corrosion product CrF₃ were measured. The results indicate that the effects of CrF₃ on melting point, enthalpy, specific heat capacity, density and thermal diffusivity of FLiNaK in liquid state are negligible within the allowable error range, meanwhile the change of thermal diffusivity is significant for FLiNaK in solid state. This work provides fundamental knowledge for the thermo-physical properties of coolant in molten salt reactor.