硅酸钙与钠及钠蒸气的相容性研究

Investigation on the compatibility of calcium silicate thermal insulation with sodium and sodium vapor

中国实验快堆主容器上方旋塞采用硅酸钙制品作为绝热材料,该材料存在与钠蒸气以及液态钠接触的可能性。通过开展硅酸钙绝热材料在高温钠、钠蒸气环境中的腐蚀实验,并对实验后样品进行表面形貌、剖面形貌以及导热性能测量等观察分析,以评估该材料与高温钠和钠蒸气环境的相容性能。结果表明:硅酸钙在液态钠和钠蒸气中不发生激烈的化学反应;液态钠和钠蒸气对硅酸钙的作用仅发生在表层,硅酸钙材料内部的颜色及形貌与试验前没有区别,未见钠的渗入,也未见任何裂纹或破损;试验后硅酸钙材料的热导性能与试验前基本相同,液钠和钠蒸气对硅酸钙的绝热性能基本没有影响。硅酸钙表现出较好的抗钠腐蚀性能。

[Background]Calcium silicate products were used as thermal insulation for China Experimental Fast Reactor(CEFR)cock,which might in contact with sodium vapor and liquid sodium.[Purpose]This study aims to investigate the compatibility of calcium silicate thermal insulation with sodium and sodium vapor.[Methods]First of all,gloves box purified by argon circulating and static testing facility of high temperature sodium were employed to build a test platform.The tests of the compatibility of calcium silicate insulation with high temperature sodium vapor and sodium at 250℃for duration ranges from 3 min to 1500 h.After the test,some examinations include surface morphology analysis,cross section morphology analysis and thermal conductivity were performed.[Results]The results show that there is no fierce reaction occurred between calcium silicate insulation with sodium and sodium vapor.Varitions of color and appearance only appear on the surface of the samples,not inside the sample.During the fabrication process of the insulation post-test,the samples do not become brittle or soft.The thermal conductivity of the samples remains constant before and after the test,sodium and sodium vapor have no effect on the thermal insulation property of samples.[Conclusions]The calcium silicate has good resistance to sodium and sodium vapor corrosion.