电化学原位分析FLiBe体系中微量杂质浓度的研究

氟锂铍熔盐（FLiBe）作为熔盐堆一回路冷却盐，在制备纯化及使用过程中需要经常分析氧、硫酸根、二价铬、三价铬四种杂质离子浓度。实验室通常采用在线取样与离线分析相结合的方法，分别采用LECO分析仪测定氧离子浓度，离子色谱仪测定硫酸根离子浓度，电感耦合等离子体发射光谱仪分析总铬浓度，制样步骤繁琐，分析周期长，难以满足FLiBe熔盐制备纯化和使用过程中对产品质量进行实时监控的需要。本项目拟采用循环伏安法、方波伏安法、计时电流法、计时电位法等电化学分析方法研究FLiBe体系氧、硫酸根、二价铬、三价铬四种杂质离子的电化学反应机理，选用合适的电分析方法分别建立氧、硫酸根、二价铬、三价铬四种杂质离子浓度与峰值电流、电量等电化学参数的定量关系，从而实现待测离子的快速检测，为熔盐堆技术远程在线测试杂质离子浓度提供理论支持。

FLiBe molten salt was employed as the primary coolant in molten salt reactor (MSR), which needed to analyze the concentration of trace impurities of oxide, sulfate, chromium (ii) and chromium (iii) ions in the process of preparation, purification and application. The method of online sampling combined offline analysis was normally used to determine the concentration of oxide ions by LECO analyzer, sulfate ions by ion chromatography (IC) and chromium by inductively coupled plasma optical emission spectrometer（ICP-OES）, respectively, which contained tedious sample preparation and long analysis period. It could hardly realize the target of real-time monitoring the quality of FLiBe molten salt. Therefore, this project aimed at using electrochemical techniques including cyclic voltammetry (CV), square wave voltammetry (SWV), chronoamperometry (CA) and chronopotentiometry (CP) to study the electrochemical reaction mechanism of oxide, sulfate, chromium (ii) and chromium (iii) ions in FLiBe molten salt, and then suitable electrochemical methodology would be designated to establish the quantitative relation between the electrochemical parameters covering peak current density and charges with the concentration of oxide, sulfate, chromium (ii) and chromium (iii) ions. Consequently, rapid concentration detection of these ions could be achieved, which provided theoretical support for long distance online testing in molten salt reactor.