核电厂堆芯热电偶接头故障修复工艺方法研究

Method research of malfunction repair technology of in-core thermocouple connector in nuclear plant

M310堆型核电厂的堆芯热电偶用于堆芯冷却剂温度监测,是堆芯参数监视的关键设备。因特殊的使用环境,热电偶设计为分段式结构,其各段间的连接器成了易损点,而其中的A接头最易损坏,而热电偶更换困难。为了应对堆芯热电偶A接头的故障,探索一套可行的维修方案,通过改进原接插件,增加注胶套件,以容纳绝缘、密封树脂和铠装固定;采用柔性芯线作为接头信号引出线,提高操作灵活度;应用绝缘的热凝固树脂密封,有利于除潮处理;应用冷压压接工艺,芯线连接可靠性高、易操作,采用绝缘瓷珠刚性分隔和树脂填充胶粘的综合绝缘处理方案,方案稳定高效;采用卡套进行铠装固定,成熟可靠;提出了高温热环物理屏蔽潮气方案,确保绝缘关键参数可控。

The in-core thermocouples of M310 Nuclear Plant are used to measure the temperature of core coolant,which are key equipment for monitoring the core. The in-core thermocouple is designed to be several segments for the special using environment. The junctions are easy to damage for its special structure, especially the A-junction,while it’s hard to replace the damaged core thermocouple. A kind of feasible maintenance method is researched,for the damaged A-junction repair. The original connector is added two special tube accessories for injecting resin,and accommodating porcelain bead, and shield fixing. A kind of flexible conductor is chosen as the signal lead of A-junction, so that improving the flexible of maintenance. A kind of insulation resin solidified when it is heated, is used for sealing treatment, and is benefit to keep dry. The cold crimping connection technology is applied in the signal wires connection, which is easy to connect and reliable. The insulation treatment, that a porcelain bead is used for rigid insulation separated and fully filling with resin,is stable and efficient. A ferrule is used for sheathing repair, which is technological maturity and reliable. The high temperature ring theory for physical shielding is put forward to shied moisture, so that make sure the key insulation of thermocouple is under control.