单节热离子燃料元件燃料质量迁移及其对元件性能影响  

Fuel Mass Transfer in Single-cell Thermionic Fuel Element and Its Influence on Fuel Performance

作　　者：雷华桢[1] 钟武烨 姜玮[1] 赵振华 LEI Huazhen;ZHONG Wuye;JIANG Wei;ZHAO Zhenhua(China Institute of Atomic Energy,Beijing 102413,China;China Institute of Nuclear Industry Strategy,Beijing 100048,China)

机构地区：[1]中国原子能科学研究院,北京102413 [2]中核战略规划研究总院,北京100048

出　　处：《原子能科学技术》2023年第8期1592-1605,共14页Atomic Energy Science and Technology

基　　金：核工业基础研究项目(CNNC-JCYJ-202226)。

摘　　要：单节热离子燃料元件结构紧凑,能够实现静态热电转换,但运行温度高,燃料发生质量迁移,影响燃料元件性能。针对单节热离子燃料元件几何特点建立燃料质量迁移模型和热电转换模型,开发单节热离子燃料元件稳态性能分析程序,将计算结果与中国原子能科学研究院堆内试验数据对比验证后,开展了单节热离子燃料元件稳态性能分析。研究发现燃料轴向质量迁移使燃料元件功率发生轴向再分布,从而展平轴向温度分布,使热电转换效率发生小幅下降。燃料元件运行功率越高,中心孔道初始直径越小,中心孔道堵塞风险越高。径向质量迁移使燃料芯块和发射极在运行早期即发生接触,发射极在接触下发生蠕变,蠕变量受燃料芯块轴向质量迁移影响。With a compact structure,static thermoelectric conversion can be achieved by the single-cell thermionic fuel element(single-cell TFE),which shows obvious technical advantages and broad application prospects.However,fuel mass transfer occurs due to extremely high operating temperature(over 2000 K),which affects the performance of the single-cell TFE in different fields.With the consideration of the geometric characteristics of single-cell TFE,the fuel mass transfer model,thermionic conversion model and mechanical model were built according to the circuit connection of the single-cell TFE.Based on above models,the steady-state performance analysis code for the single-cell TFE was developed.A comparison between the calculation results with the in-reactor test data of China Institute of Atomic Energy was carried out to further verify the thermal calculation function of the code and the calculation result and it shows good agreement with the test result.After that,the steady-state performance analysis of the single-cell TFE was carried out.The study indicates that the main component of fuel mass transfer is uranium dioxide when sub-chemical dose of uranium dioxide is used.In the central channel,fuel evaporates in the relative high temperature area and condensates in the low temperature area.The axial mass transfer of the fuel increases the diameter of the central channel in the higher temperature region and decreases in the lower temperature region on both side.Under the combined action of temperature and migration distance,the position corresponding to the minimum diameter of the center channel is not at both ends,but there is a certain distance between the position and the two ends of the central channel.The axial fuel mass transfer causes the axial redistribution of the power of the fuel element,thereby the axial temperature distribution is smeared obviously,and the maximum axial temperature difference in the inner wall of the fuel decreases significantly.The risk of central channel blocking is higher with higher t

关 键 词：单节热离子燃料元件 燃料质量迁移 热离子转换 发射极变形 

分 类 号：TL333[核科学技术—核技术及应用]