Water affects the glass melting process by interacting with the foam layer at the glass melt surface and by influencing the batch conversion reactions. Nuclear waste aqueous slurry feed maintains a high water vapor pressure in the melter atmosphere. To investigate to what extent water vapor affects the foaming during vitrification of nuclear waste in joule‐heated cold‐top melters, a series of feed expansion experiments were performed under humid and dry atmospheres using samples of low‐activity waste (LAW) melter feed simulants. Melting of feed pellets in the presence of water vapor slightly decreased the temperature of primary foam onset for an extensively foaming feed, but did not significantly affect the feed volume expansion by foaming or the foam‐collapse temperature. Sets of feed expansion experiments and evolved gas analyses were also performed to check the effect of thermal history on conversion behavior of LAW feed samples. The thermal history was varied by testing feed samples prepared as direct slurry, loose powder, and slow‐ and fast‐dried pellets. The sample preparation methods and the sample shape were not found to influence foaming parameters, except for the direct slurry where the low‐temperature swelling prevented the foam onset and collapse temperatures to be determined.

中文翻译：

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水蒸气和热历史对核废料转化为玻璃的影响

水通过与玻璃熔体表面的泡沫层相互作用并影响间歇转化反应，从而影响玻璃的熔融过程。核废料含水浆液进料在熔化器气氛中维持高水蒸气压。为了研究在焦耳加热的冷顶熔化器中水蒸气在多大程度上影响核废料玻璃化期间的泡沫，在湿润和干燥的气氛下使用低活性废物（LAW）熔化器进料模拟物样品进行了一系列进料膨胀实验。在水蒸气存在的情况下，饲料颗粒的熔化会稍微降低广泛发泡饲料的初生泡沫的温度，但不会显着影响起泡或泡沫破裂温度对饲料体积膨胀的影响。还进行了一组进料膨胀实验和逸出气体分析，以检查热历史对LAW进料样品转化行为的影响。通过测试饲料样品（直接浆液，散粉以及慢速和快干颗粒）来改变热历史。没有发现样品制备方法和样品形状会影响发泡参数，除了直接浆液外，低温膨胀阻止了泡沫的开始和破裂温度的确定。