Oxidation of U3Si2: The role of exothermic energy
Oxidation of U3Si2: The role of exothermic energy
复制标题
U3Si2 的氧化：放热能的作用
DOI：
10.1016/j.jnucmat.2022.153874
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发表时间：
2022
影响因子：
3.1
通讯作者：
Worth R
中科院分区：
文献类型：
--
作者：
Worth R
硅化铀 (U3Si2) 是正在考虑用于发电核反应堆的候选耐事故燃料材料之一。这种燃料材料的开发，包括大规模生产路线，以及可能影响该路线的因素仍在调查中。其中一个因素是氧气对材料的影响以及随后释放的放热能。这项工作采用热重和差示扫描量热 (DSC) 相结合的方法来研究电弧熔化 U3Si2 材料的氧化，包括斜坡测试、等温实验和不同的粒径。研究发现，碎片和小粉末样品之间的质量增益曲线存在差异，碎片在明显更短的时间内提供相同的热负荷（∼4.6 ± 0.5 kJ.g−1）。一旦对反应产物中元素硅的存在进行校正，测得的放热热量输出就与热力学模型一致。快速氧化的起始温度也随着颗粒尺寸的增加而降低。等温实验期间新鲜制备的粉末样品的初始反应性给出了适当的反应常数，用于构建阿伦尼乌斯图。支持 DSC 数据表明，较高温度数据点之一（本例中为 275 °C）表现出放热能量诱导的自加热和加速的反应速率。计算得出的新制备的 U3Si2 粉末氧化活化能约为 36 kJ.mol−1。
Uranium silicide (U3Si2) is one of the candidate accident tolerant fuel materials under consideration for adoption in power producing nuclear reactors. The development of this fuel material including the bulk scale manufacturing route, and factors which may affect this route, are still under investigation. One such factor is the influence of oxygen on the material and the consequent release of exothermic energy. This work uses combined thermogravimetric and differential scanning calorimetry (DSC) methods to study oxidation of arc melted U3Si2material, including ramp tests, isothermal experiments and varying particle sizes. It is found that there is a difference in mass gain profile between fragments and small powder samples, with fragments delivering the same heat load (∼4.6 ± 0.5 kJ.g−1) over a significantly shorter period of time. The measured exothermic heat output is in agreement with thermodynamic modelling once corrections have been made for the presence of elemental silicon in the reaction product. The onset temperature of rapid oxidation also reduces with particle size. Initial reactivities of freshly prepared powder samples during isothermal experiments give appropriate reaction constants, which are used to construct an Arrhenius plot. Supporting DSC data indicate that one of the higher temperature data points (275 °C in this instance) had exhibited exothermic energy-induced self-heating and an accelerated rate of reaction. The resultant calculated activation energy from oxidation of freshly prepared U3Si2powder is approximately 36 kJ.mol−1.