The Effects of Uranium and Oxygen Ratio on the Thermophysical Properties of Multicomponent Molten Uranium Alloys

今年的研究有两个主要目标：1.评估在接近3000K的温度下，用于测量热容的“多气体冷却法”的表现如何。开发一种新的密度测量技术。去年，我开发了一种高温液体材料的热容测量方法，称为多气体冷却法。在方法开发阶段，大多数实验是在低熔点的贵金属上进行的。然而，铀和氧化锆等与核安全密切相关的材料的熔点接近3000K。因此，了解多气体冷却法是否能够在更恶劣的条件下产生准确的结果是至关重要的。今年对Mo、Rh和Ir等各种过渡金属的热容进行了评估，证实了即使在测量熔点接近3000K的材料时，“多气体冷却法”也是准确和可靠的。对于密度测量，目前使用的空气动力悬浮方法需要估计样品的形状，因为悬浮喷嘴部分阻塞了样品的形状。这引发了人们对估计样本量的不确定性的担忧。这项研究中开发的“滴法”使用了一个可拆分的喷嘴，它在悬浮后滴落熔融的样品。当从侧面观察时，整个样本是可见的，不需要估计。测得液态铂的熔点密度为19.17g/cm~3，与文献值吻合较好。

There are two main goals for this year’s research:1. Evaluate how well the ‘multiple-gas cooling method’ for heat capacity measurement performs at temperatures approaching 3000 K.2. Develop a new density measurement technique.Last year, I developed a heat capacity measurement method for high-temperature liquid materials called the ‘multiple-gas cooling method.’ Most of the experiments were performed on noble metals with low melting points during the method development phase. However, materials such as uranium and zirconium oxides that are closely related to nuclear safety have melting points close to 3000 K. Therefore, it is crucial to understand whether the ‘multiple-gas cooling method’ is capable of producing accurate results under much harsher conditions. The heat capacity of various transition metals such as Mo, Rh, and Ir was evaluated this year and confirmed the accuracy and reliability of the ‘multiple-gas cooling method’ even when used to measure materials with melting points near 3000 K.For density measurements, current methods used with aerodynamic levitation require one to estimate the sample's shape because it is partially blocked by the levitation nozzle. This raises concerns about the uncertainty of the estimated sample volume. The ‘drop-method’ developed in this work uses a splittable nozzle that drops the molten sample after levitation. The entire sample is visible when viewed from the side, and no estimations are necessary. The measured density of liquid platinum at its melting point was 19.17 g/cm3, which agrees well with literature values.