In order to explore the reduction pathways of zinc oxide in LiCl molten salt and the optimal process,experiments were conducted in an alumina crucible using metallic lithium as the reducing agent and lithium chloride ...In order to explore the reduction pathways of zinc oxide in LiCl molten salt and the optimal process,experiments were conducted in an alumina crucible using metallic lithium as the reducing agent and lithium chloride molten salt as the reaction medium at 923 K.The study assessed the effects of lithium thermochemical reduction and electrolytic reduction of ZnO.The volatilization behavior of metal oxides in molten salts,the equivalent of a reducing agent,reduction time,amount of molten salt,stirring time,and the method of reduction feed were investigated for their impacts on the reduction yield and product composition.X-ray powder diffraction(XRD)analysis of the products showed that lithium reduction of ZnO not only produced metallic Zn but also formed a LiZn alloy.Electrolytic reduction can be used to obtain the metallic Zn product by controlling the potential below-2.2 V(vs Ag/Ag^(+)).Moreover,sintered oxides and higher electrode potentials could enhance the efficiency of electrolysis.Under the optimal reaction conditions determined experimentally,the lithium reduction experiment achieved a yield of 77.2%after a 12-h test,and the electrolytic reduction reached a yield of 85.4%after a 6-h test.展开更多
Electro-reduction of spent nuclear oxide fuels in molten salt was the key step of pyroprocessing for oxide fuel treatment. In the present study, the E-pO^2- diagram for rare earth elements in molten Li Cl-KCl at 450 o...Electro-reduction of spent nuclear oxide fuels in molten salt was the key step of pyroprocessing for oxide fuel treatment. In the present study, the E-pO^2- diagram for rare earth elements in molten Li Cl-KCl at 450 oC were developed based available experimental data. E-pO^2- diagrams could show the stability of each chemical compound in the salt, and therefore, the diagrams could be applied to predict experimental conditions for electro-reduction of spent nuclear fuel efficiently. Compared with the available E-pO^2-diagrams, the present study concerned the activity coefficient of the element studied in the molten salt in all reactions, which made the diagram be more reliable and accurate.展开更多
Korea imports about 97% of its energy resources as its available energy resources are extremely limited. Thus, the role of nuclear power in electricity generation is expected to become more important in future years. ...Korea imports about 97% of its energy resources as its available energy resources are extremely limited. Thus, the role of nuclear power in electricity generation is expected to become more important in future years. A fast reactor system is one of the most promising options for electricity generation with an efficient utilization of uranium resources and a reduction of radioactive wastes. Based on the experiences gained during the development of the conceptual designs for KALIMER （Korea advanced liquid metal reactor）, the KAERI （Korea Atomic Energy Research Institute） is currently developing advanced SFR （sodium cooled fast reactor） design concepts that can better meet the Gen IV （Generation IV） technology goals. The long-term advanced SFR development plan will be carried out toward the construction of an advanced SFR demonstration plant by 2028. Advanced concept design studies and the development of the advanced SFR technologies necessary for its commercialization and basic key technologies carried out by KAERI are included in this paper.展开更多
This work presents a comprehensive study for the electrochemical behaviors of zirconium in LiCl-KCl eutectic.The effects of stirring,temperature and Zr concentration on the electrode reactions,the ZrCl_4 sublimation f...This work presents a comprehensive study for the electrochemical behaviors of zirconium in LiCl-KCl eutectic.The effects of stirring,temperature and Zr concentration on the electrode reactions,the ZrCl_4 sublimation from the melt,microcosmic morphologies of Zr deposits(ZrCl and Zr)obtained at different potential and temperature have been investigated.The behaviors of Zr(Ⅳ),on a large concentration range from 0.13%to 2.28%in melt,show a multiple-step reaction involving Zr(Ⅳ),Zr(Ⅱ),ZrCl and Zr species.Temperature plays a crucial role on the changes of Zr(IV)reduction behavior on the solid electrode.The Zr(Ⅳ)/ZrCl couple is more easily observed at lower temperature and gradually diminishes with the increase of temperature.The Zr(Ⅳ)/Zr(Ⅱ)and Zr(Ⅱ)/Zr reactions are predominant on the W electrode at higher temperatures.At 673 K,a layered structure of insoluble ZrCl formed by potentiostatic electrolyses at 1.1 V was visualized by scanning electron microscopy-energy dispersive X-ray(SEM-EDS),while only Zr metal particles was observed at higher temperature than 773 K.An evolution of the Zr-based structure and size corresponding to the ZrCl and Zr metal based on different potentiostatic electrolysis was observed.The average particle size of the Zr metalparticles increases with the increase of temperature.展开更多
文摘In order to explore the reduction pathways of zinc oxide in LiCl molten salt and the optimal process,experiments were conducted in an alumina crucible using metallic lithium as the reducing agent and lithium chloride molten salt as the reaction medium at 923 K.The study assessed the effects of lithium thermochemical reduction and electrolytic reduction of ZnO.The volatilization behavior of metal oxides in molten salts,the equivalent of a reducing agent,reduction time,amount of molten salt,stirring time,and the method of reduction feed were investigated for their impacts on the reduction yield and product composition.X-ray powder diffraction(XRD)analysis of the products showed that lithium reduction of ZnO not only produced metallic Zn but also formed a LiZn alloy.Electrolytic reduction can be used to obtain the metallic Zn product by controlling the potential below-2.2 V(vs Ag/Ag^(+)).Moreover,sintered oxides and higher electrode potentials could enhance the efficiency of electrolysis.Under the optimal reaction conditions determined experimentally,the lithium reduction experiment achieved a yield of 77.2%after a 12-h test,and the electrolytic reduction reached a yield of 85.4%after a 6-h test.
基金Project supported by DOE Office of Nuclear Energy’s Nuclear Energy University Programs(14-6489)
文摘Electro-reduction of spent nuclear oxide fuels in molten salt was the key step of pyroprocessing for oxide fuel treatment. In the present study, the E-pO^2- diagram for rare earth elements in molten Li Cl-KCl at 450 oC were developed based available experimental data. E-pO^2- diagrams could show the stability of each chemical compound in the salt, and therefore, the diagrams could be applied to predict experimental conditions for electro-reduction of spent nuclear fuel efficiently. Compared with the available E-pO^2-diagrams, the present study concerned the activity coefficient of the element studied in the molten salt in all reactions, which made the diagram be more reliable and accurate.
文摘Korea imports about 97% of its energy resources as its available energy resources are extremely limited. Thus, the role of nuclear power in electricity generation is expected to become more important in future years. A fast reactor system is one of the most promising options for electricity generation with an efficient utilization of uranium resources and a reduction of radioactive wastes. Based on the experiences gained during the development of the conceptual designs for KALIMER （Korea advanced liquid metal reactor）, the KAERI （Korea Atomic Energy Research Institute） is currently developing advanced SFR （sodium cooled fast reactor） design concepts that can better meet the Gen IV （Generation IV） technology goals. The long-term advanced SFR development plan will be carried out toward the construction of an advanced SFR demonstration plant by 2028. Advanced concept design studies and the development of the advanced SFR technologies necessary for its commercialization and basic key technologies carried out by KAERI are included in this paper.
基金supported by the National Natural Science Foundation of China(91426302,91126006,91326202)the "Strategic Priority Research program" of the Chinese Academy of Sciences (XDA030104)
文摘This work presents a comprehensive study for the electrochemical behaviors of zirconium in LiCl-KCl eutectic.The effects of stirring,temperature and Zr concentration on the electrode reactions,the ZrCl_4 sublimation from the melt,microcosmic morphologies of Zr deposits(ZrCl and Zr)obtained at different potential and temperature have been investigated.The behaviors of Zr(Ⅳ),on a large concentration range from 0.13%to 2.28%in melt,show a multiple-step reaction involving Zr(Ⅳ),Zr(Ⅱ),ZrCl and Zr species.Temperature plays a crucial role on the changes of Zr(IV)reduction behavior on the solid electrode.The Zr(Ⅳ)/ZrCl couple is more easily observed at lower temperature and gradually diminishes with the increase of temperature.The Zr(Ⅳ)/Zr(Ⅱ)and Zr(Ⅱ)/Zr reactions are predominant on the W electrode at higher temperatures.At 673 K,a layered structure of insoluble ZrCl formed by potentiostatic electrolyses at 1.1 V was visualized by scanning electron microscopy-energy dispersive X-ray(SEM-EDS),while only Zr metal particles was observed at higher temperature than 773 K.An evolution of the Zr-based structure and size corresponding to the ZrCl and Zr metal based on different potentiostatic electrolysis was observed.The average particle size of the Zr metalparticles increases with the increase of temperature.
