Bi2212高温超导圆线是未来可控热核聚变堆中制备铠装导体（CICC）的理想候选材料，但其制备成CICC用电缆的渗漏是限制其工程应用的关键问题。本项目依据渗漏缆线具有局部渗漏和芯丝融合等共性，推测电缆渗漏的本质机理是Bi2212线材内部气体导致的银层蠕变，而线材加工的不均匀性是加速蠕变的重要诱因。为解决渗漏，本项目拟基于Bi2212喷雾粉，采用“不同银超比线材梯度组装”的方式制备线材，研究加工参数对线材加工均匀性的影响规律，揭示线材加工均匀性的优化机理；在此基础上，制备加工均匀性良好但杂质含量、银层厚度、扭绞节距不同的线材，研究上述变量对热处理后线材渗漏的影响规律来获得上述变量的安全阈值，同时设计“先高压，后封端，再常压”的特殊热处理工艺获得线材的蠕变动力学；最终制备CICC用裸缆，揭示缆线渗漏机理。此项研究工作有望解决Bi2212缆线的渗漏问题，为其在未来聚变堆中的应用奠定基础。

Bi2212 high temperature superconductor round wires is an ideal candidate for fabricating CICC used in future controlled thermonuclear fusion reactor, however in which the leakage phenomenon of the cables made by Bi2212 wires is a key problem limiting its practical application. According to the local leakage phenomenon and the fused filament feature, it’s speculated that creep of Ag caused by inner gas is the natural mechanism of leakage, while the wire processing inhomogeneity accelerates the creep of Ag. To solve the leakage problem, this project design to use the spray powder to fabricate the wire based on the gradient assembling of the wires in which its Ag and superconductor ratio is different. Then by studying how the machining parameters control the uniformity of the wire, the optimizing mechanism of the wire uniformity will be disclosed. Based on the above information, the wires with good uniformity will be made with variable parameters, including the content of the impurity, the thickness of Ag layer and the twist pitch. Then the influence of these parameters on the leakage of the wires will be obtained, as well as the safety threshold for above variables. Meanwhile the special heat treatment process of "first high pressure, then ends sealed, later normal pressure" will be used to establish the creep dynamics database and the leakage criterion. Finally the CICC naked cables will be made to disclose the leakage mechanism. This project will help to solve the leakage problem of the Bi2212 cables, and to establish foundation for its usage in the future fusion reactor.