Liquid-fueled molten-salt reactors have dynamic features that distinguish them from solid-fueled reactors,such that conventional system-analysis codes are not directly applicable.In this study,a coupled dynamic model ...Liquid-fueled molten-salt reactors have dynamic features that distinguish them from solid-fueled reactors,such that conventional system-analysis codes are not directly applicable.In this study,a coupled dynamic model of the Molten-Salt Reactor Experiment(MSRE)is developed.The coupled model includes the neutronics and single-phase thermal-hydraulics modeling of the reactor and validated xenon-transport modeling from previous studies.The coupled dynamic model is validated against the frequency-response and transient-response data from the MSRE.The validated model is then applied to study the effects of xenon and void transport on the dynamic behaviors of the reactor.Plant responses during the unique initiating events such as off-gas system blockages and loss of circulating voids are investigated.展开更多
Fluorinated rare earth molten-salt electrolytic slag contains a considerable amount of rare earth elements,as well as a variety of heavy metals and fluorides that cause environmental pollution.Therefore,it is of great...Fluorinated rare earth molten-salt electrolytic slag contains a considerable amount of rare earth elements,as well as a variety of heavy metals and fluorides that cause environmental pollution.Therefore,it is of great importance to fully utilise this resource.In this study,the transformation mechanism of fluorinated rare earth molten-salt electrolytic slag roasted with sodium carbonate,and the regulation mechanism of rare earth leaching under different roasting conditions were investigated with the help of thermodynamic calculation of the reactions and kinetic analysis.The thermodynamic and differential thermal thermogravimetric(DTA-TG)analysis shows that the transformation of rare earth fluoride to rare earth oxide is promoted at elevated temperature.Furthermore,the leaching experimental results show that increasing the temperature,time,hydrochloric acid concentration,and liquid-solid ratio can effectively promote the recovery of rare earths.The optimum experimental conditions are a roasting temperature of 700℃,roasting time of 2 h,and sodium carbonate to molten salt electrolytic slag mass ratio of 0.6,followed by leaching at 80℃with a liquid-solid ratio of 10:1 by adding 3 moI/L hydrochlo ric acid with stirring for 2 h.Under these conditions,the rare earths in the molten salt electrolytic slag are biologically transformed at a lower temperature and the leaching efficiency of rare earths exceeds 98%.展开更多
Pr^（3＋）-activated barium tungsto-molybdate solid solution phosphor Ba（Mo_（1-z）W_z）O_4：Pr^（3＋）is successfully fabricated via a facile molten-salt approach. The as-synthesized microcrystal is of truncated oct...Pr^（3＋）-activated barium tungsto-molybdate solid solution phosphor Ba（Mo_（1-z）W_z）O_4：Pr^（3＋）is successfully fabricated via a facile molten-salt approach. The as-synthesized microcrystal is of truncated octahedron and exhibits deep-red-emitting upon blue light excitation. Powder x-ray diffraction and Raman spectroscopy techniques are utilized to investigate the formation of solid solution phosphor. The luminescence behaviors depend on the resulting composition of the microcrystals with fixed Pr^（3＋）-doping concentration, while the host lattices remain in a scheelite structure. The forming solid solution via the substitution of [WO_4] for [MoO_4] can significantly enhance its luminescence, which may be due to the fact that Ba（Mo_（1-z）W_z）O_4：Pr^（3＋）owns well-defined facets and uniform morphologies. Owing to its properties of high phase purity,well-defined facets, highly uniform morphologies, exceptional chemical and thermal stabilities, and stronger emission intensity, the resulting solid solution phosphor is expected to find potential applications in phosphor-converted white lightemitting diodes（LEDs）.展开更多
In order to provide data on diffusion coefficients and solubility constants of tritium in molten salts for the critical issue of tritium control in the Thorium Molten Salt Reactor(TMSR)program,a two-chamber permeabili...In order to provide data on diffusion coefficients and solubility constants of tritium in molten salts for the critical issue of tritium control in the Thorium Molten Salt Reactor(TMSR)program,a two-chamber permeability apparatus separated by a nickel plate had been developed for determining the permeability of hydrogen isotope in molten salts.Descriptions on the permeability apparatus,experimental procedure and the analytical method for determining the diffusivity and solubility of hydrogen isotope in molten salts were presented in this paper.To assess the performance of the apparatus,the blank tests without molten salt were conducted at300-700℃.The results showed that the nickel plate acting as the window for hydrogen isotope permeation in the apparatus seemed to have less effect on experiments of determining the permeability of hydrogen isotope in molten slat at 500-700℃.Furthermore,the applicability of the apparatus with molten salt was also evaluated experimentally,with test experiments of molten Flinak(LiF-NaF-KF)at 500℃,600℃and 700℃.Diffusion coefficients and solubility constants of hydrogen in molten Flinak can be derived from those test experiments,which were correlated to D_(Flinak-H)=7.06×10^(-5)e^(-54.9/(R_gT))m^2/s and s_(Flinak-H)=1.67×10^(-7)e^(27.0/(r_gt))mol-H_2/(m^3 Pa).展开更多
Sr0.6 Ba0.4 Nb2 O6 micro-rods are prepared by the molten-salt method with K2 SO4,KCl-K2 SO4,and KCl as fluxes.It reveals that the Sr0.6 Ba0.4 Nb2 O6 synthesized with KCl as a flux exhibits a single phase with tetragon...Sr0.6 Ba0.4 Nb2 O6 micro-rods are prepared by the molten-salt method with K2 SO4,KCl-K2 SO4,and KCl as fluxes.It reveals that the Sr0.6 Ba0.4 Nb2 O6 synthesized with KCl as a flux exhibits a single phase with tetragonal tungsten bronze structure.The measurement of X-ray diffraction indicates that the Sr0.6 Ba0.4 Nb2 O6 micro-rods synthesized at 1 300℃are anisotropic.The morphology of the powers is examined by transmission electron microscope.It reveals that the length-diameter ratio of Sr0.6 Ba0.4 Nb2 O6 micro-rods increases with increasing annealing temperature from 900℃to 1 300℃.At 1 300℃,the rod possesses a large length-diameter ratio of 8∶1.Moreover,the analysis of the piezoelectric properties of single micro-rods using apiezo-response force microscope indicates that the domains of the material are arranged along its radial direction.展开更多
液体燃料熔盐堆是第四代先进核能系统的候选堆型之一,应急排盐冷却系统是其可设置的特殊安全设计。本文以熔盐实验堆(Molten Salt Reactor Experiment,MSRE)应急排盐冷却系统为研究对象,探究换热元件内层屏障破损对其正常余热导出功能...液体燃料熔盐堆是第四代先进核能系统的候选堆型之一,应急排盐冷却系统是其可设置的特殊安全设计。本文以熔盐实验堆(Molten Salt Reactor Experiment,MSRE)应急排盐冷却系统为研究对象,探究换热元件内层屏障破损对其正常余热导出功能的影响。该研究基于计算流体动力学(Computational Fluid Dynamics,CFD)模拟方法,通过构建传热和多相流动模型分析破损后的传热和流动现象,并对关键影响参数进行敏感性分析。结果表明,内层套管破损后,18.4%的冷却水从破损位置经气隙层流出,单根换热元件功率提升到29.434 kW,破损位置附近外层套管出现局部温度低点。敏感性分析结果表明,破损尺寸、破损位置和气隙层压力变化均会对换热元件传热产生明显影响,其中传热对破损尺寸的敏感性最强。该分析结果可以为熔盐堆应急排盐冷却系统工程设计提供研究数据。展开更多
基金partly supported by the University of Shanghai for Science and Technology(No.10-24-301-101)。
文摘Liquid-fueled molten-salt reactors have dynamic features that distinguish them from solid-fueled reactors,such that conventional system-analysis codes are not directly applicable.In this study,a coupled dynamic model of the Molten-Salt Reactor Experiment(MSRE)is developed.The coupled model includes the neutronics and single-phase thermal-hydraulics modeling of the reactor and validated xenon-transport modeling from previous studies.The coupled dynamic model is validated against the frequency-response and transient-response data from the MSRE.The validated model is then applied to study the effects of xenon and void transport on the dynamic behaviors of the reactor.Plant responses during the unique initiating events such as off-gas system blockages and loss of circulating voids are investigated.
基金supported by the National Key Research and Development Project of China(2018YFC1903400)Key Research and Development Program of Jiangxi Province(20212BBG73049)+1 种基金Jiangxi Provincial Department of Education Science and Technology Research Project(GJJ190486)Excellent Doctoral Dissertation Cultivating Project of Jiangxi University of Science and Technology(202202400013)。
文摘Fluorinated rare earth molten-salt electrolytic slag contains a considerable amount of rare earth elements,as well as a variety of heavy metals and fluorides that cause environmental pollution.Therefore,it is of great importance to fully utilise this resource.In this study,the transformation mechanism of fluorinated rare earth molten-salt electrolytic slag roasted with sodium carbonate,and the regulation mechanism of rare earth leaching under different roasting conditions were investigated with the help of thermodynamic calculation of the reactions and kinetic analysis.The thermodynamic and differential thermal thermogravimetric(DTA-TG)analysis shows that the transformation of rare earth fluoride to rare earth oxide is promoted at elevated temperature.Furthermore,the leaching experimental results show that increasing the temperature,time,hydrochloric acid concentration,and liquid-solid ratio can effectively promote the recovery of rare earths.The optimum experimental conditions are a roasting temperature of 700℃,roasting time of 2 h,and sodium carbonate to molten salt electrolytic slag mass ratio of 0.6,followed by leaching at 80℃with a liquid-solid ratio of 10:1 by adding 3 moI/L hydrochlo ric acid with stirring for 2 h.Under these conditions,the rare earths in the molten salt electrolytic slag are biologically transformed at a lower temperature and the leaching efficiency of rare earths exceeds 98%.
基金Project supported by the Construction Fund for Science and Technology Innovation Group from Jiangsu University of Technology,Chinathe Key Laboratory of Atmospheric Environment Monitoring and Pollution Control,China(Grant No.KHK1409)+1 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions,Chinathe National Natural Science Foundation of China(Grant No.21373103)
文摘Pr^（3＋）-activated barium tungsto-molybdate solid solution phosphor Ba（Mo_（1-z）W_z）O_4：Pr^（3＋）is successfully fabricated via a facile molten-salt approach. The as-synthesized microcrystal is of truncated octahedron and exhibits deep-red-emitting upon blue light excitation. Powder x-ray diffraction and Raman spectroscopy techniques are utilized to investigate the formation of solid solution phosphor. The luminescence behaviors depend on the resulting composition of the microcrystals with fixed Pr^（3＋）-doping concentration, while the host lattices remain in a scheelite structure. The forming solid solution via the substitution of [WO_4] for [MoO_4] can significantly enhance its luminescence, which may be due to the fact that Ba（Mo_（1-z）W_z）O_4：Pr^（3＋）owns well-defined facets and uniform morphologies. Owing to its properties of high phase purity,well-defined facets, highly uniform morphologies, exceptional chemical and thermal stabilities, and stronger emission intensity, the resulting solid solution phosphor is expected to find potential applications in phosphor-converted white lightemitting diodes（LEDs）.
文摘In order to provide data on diffusion coefficients and solubility constants of tritium in molten salts for the critical issue of tritium control in the Thorium Molten Salt Reactor(TMSR)program,a two-chamber permeability apparatus separated by a nickel plate had been developed for determining the permeability of hydrogen isotope in molten salts.Descriptions on the permeability apparatus,experimental procedure and the analytical method for determining the diffusivity and solubility of hydrogen isotope in molten salts were presented in this paper.To assess the performance of the apparatus,the blank tests without molten salt were conducted at300-700℃.The results showed that the nickel plate acting as the window for hydrogen isotope permeation in the apparatus seemed to have less effect on experiments of determining the permeability of hydrogen isotope in molten slat at 500-700℃.Furthermore,the applicability of the apparatus with molten salt was also evaluated experimentally,with test experiments of molten Flinak(LiF-NaF-KF)at 500℃,600℃and 700℃.Diffusion coefficients and solubility constants of hydrogen in molten Flinak can be derived from those test experiments,which were correlated to D_(Flinak-H)=7.06×10^(-5)e^(-54.9/(R_gT))m^2/s and s_(Flinak-H)=1.67×10^(-7)e^(27.0/(r_gt))mol-H_2/(m^3 Pa).
基金supported by the National Natural Science Foundation of China(No.11475086)
文摘Sr0.6 Ba0.4 Nb2 O6 micro-rods are prepared by the molten-salt method with K2 SO4,KCl-K2 SO4,and KCl as fluxes.It reveals that the Sr0.6 Ba0.4 Nb2 O6 synthesized with KCl as a flux exhibits a single phase with tetragonal tungsten bronze structure.The measurement of X-ray diffraction indicates that the Sr0.6 Ba0.4 Nb2 O6 micro-rods synthesized at 1 300℃are anisotropic.The morphology of the powers is examined by transmission electron microscope.It reveals that the length-diameter ratio of Sr0.6 Ba0.4 Nb2 O6 micro-rods increases with increasing annealing temperature from 900℃to 1 300℃.At 1 300℃,the rod possesses a large length-diameter ratio of 8∶1.Moreover,the analysis of the piezoelectric properties of single micro-rods using apiezo-response force microscope indicates that the domains of the material are arranged along its radial direction.
