【作者】 程进辉；

【导师】 黎忠；

【作者基本信息】 中国科学院研究生院（上海应用物理研究所） ， 核技术及应用， 2014， 博士

【摘要】 液态熔盐由于体热容量大；低粘度、流动性好；低蒸汽压；较宽的工作温度范围；同时还具有较大的裂变材料溶解度，可用于熔盐堆中的最为燃料溶剂；是核能及太阳能传蓄热应用中良好的热工介质。熔盐的熔点、密度、粘度、热容、表面张力、导热系数等热物性参数是传热系统热工设计及安全分析中的基本参数，不但涉及到热量的传输的效率，更关系到整个系统的安全。论文针对熔盐堆物理、热工以及安全设计的需要，采用实验测量以及相图热力学计算的方法，系统研究用于传蓄热系统中的熔盐热物性。本文采用商用相图计算软件Facsage6.4和Pandat优化计算了LiF-NaF-KF熔盐体系的相图，并建立相关的热力学数据库。采用文献报道的较为可靠的LiF-BeF2-ThF4-UF4体系的的相图优化结果，建立了该体系的相图热力学数据库，为熔盐堆中液态燃料的制备与燃料盐配比的优化提供参考。本论文在详细调研熔盐热物性的测试方法与市场上的物性测试仪器情况的基础上，确定了熔盐物性参数测试的方法，即采用阿基米德法、步冷曲线法、最大气泡压力法、旋转法、激光闪光法、差示扫描量热法分别测量熔盐的密度、初晶温度/熔点、表面张力、粘度、导热系数和热容等参数。为此，自主研制了旋转法高温粘度仪，搭建了熔盐密度测试仪，改进了激光导热仪等熔盐物性测量设备，建立了熔盐密度、表面张力以及初晶温度的测试方法和实验规范，测量精度和误差均满足熔盐传热所需的要求。验证了旋转法用于低粘度熔盐测量的可行性，并取得了较好的常温低粘度测量结果。设计了闪光法液体热扩散测试的坩埚，确定了熔盐液体测试的样品制备方法及测试规范，测量结果与文献报道的结果基本吻合。建立了差示扫描量热法测量熔盐熔点、熔化焓和热容的实验方法和规范，测试结果满足传蓄热熔盐的设计要求。总的来说，实现了高温熔盐的粘度、密度、初晶温度、表面张力与导热系数的准确测定。利用上述仪器和建立的实验规范，测量了NaNO3-KNO3(60-40wt%)、NaNO3-NaNO2-KNO3（7-40-53wt%）、Li2CO3-Na2CO3-K2CO3（32.1-33.4-34.5wt%）、KCl-MgCl2(66-34mol%)、LiF-NaF-KF（46.5-11.5-42mol%）、KF-ZrF4(58-42mol%)等六个个典型的硝酸盐、碳酸盐、氯化盐和氟化盐体系热物性。这些结果为熔盐在核能和太阳能中的传热蓄热应用提供了具有参考价值的数据，尤其是FLiNaK的热物性参数的测定，为钍基熔盐堆二回路使用FLiNaK的确定提供了依据。更多还原

【Abstract】 Molten salt is an ideal medium for heat transfer and storage in nuclear reactor andconcentrated solar power system because of its low viscosity, low vapor pressure at hightemperature, large specific capacity, high thermal conductivity and wide temperature range.Thermophysical properties such as liquidus temperature, density, viscosity, thermalconductivity, heat capacity are basic parameters for thermal hydraulics concerning theefficiency of heat transfer, and safety analysis involving the safty of the whole system.According to requirements of heat transfer system design and Molten Salt Reactor physicsanalysis, this paper focuses on the investigation on the thermophysical properties of moltensalts by experimental determination and CALPHAD（CALculation of Phase Diagram）method.Facsage6.4and Pandat were used to optimize the LiF-NaF-KF ternary phase diagrams,and the relevant databases were obtained. The phase diagrams of LiF-BeF2-ThF4-UF4werecalculated by using the well optimized parameters of each phase from literature.After a detailed investigation of the measurement method of thermophysical propertiesfor molten salts, the Archimedes, cooling curves, bubble maximum pressure, rotating anddifferential scanning calorimetry methods were adopted to determine the density, liquidustemperature, surface tension, viscosity and heat capacity of molten salts respectively.In order to get accurate levels of thermophysical properties of molten salts, theintegrated testing device for density, liquidus temperature and surface tension measurement,rotating viscometer, Laser flash themal analyzer and DSC were developed or improvedrespectively. The experimental results of density, liquidus temperature and surface tensionmeasurements were well enough for the needs of heat transfer design. The feasibility of lowviscosity measurement by rotating method was verified, and good experimental results wereobtained in conditions of room temperature. A special crucible was designed and thecorresponding method of sample preparation was established for the thermal diffusivitymeasurement of liquid salts. The experimental specifications of heat capacity measurementfor liquid salts by DSC were explored and preliminary results were gained.The thermophysical properties of NaNO3-KNO3(60-40wt%), NaNO3-NaNO2-KNO3（7-40-53wt%）, Li2CO3-Na2CO3-K2CO（332.1-33.4-34.5wt%）, KCl-MgCl2(66-34mol%),LiF-NaF-KF（46.5-11.5-42mol%）, KF-ZrF4(58-42mol%) were obtained by experimentmeasurement, and the corresponding thermophysical properties database can providereference for the applications of these salts in heat transfer and storage.更多还原