Given the superior thermal stability and highly attainable hydrogen density, yttrium hydride is an excellent high-temperature moderator material in advanced thermal neutron spectrum reactors that require small core volumes. Large-scale, crack-free, bulk yttrium hydride is in high demand; however, fabrication of yttrium hydride is challenging and has not been demonstrated for nearly half century. The associated challenges are discussed herein. In response to these challenges, a hydriding system was designed and constructed at Oak Ridge National Laboratory and was used to successfully fabricate crack-free yttrium hydride in complex geometries at large scales. This was accomplished by precisely controlling the hydrogen’s partial pressure and the retort temperature, which was informed by the well-established thermodynamic properties of the binary H–Y system. Hydrogen content in as-fabricated hydride was determined by weight change, an approach which was considered reliable based on the use of ultra–high-purity yttrium, the absence of oxide phases up to levels detectable using x-ray diffraction (XRD), and the significant weight gain. Hydrogen distribution along one yttrium hydride rod was evaluated with XRD analysis on materials extracted from different locations on the rod. The results indicated a relatively homogeneous hydrogen distribution along the hydride rod, with <3% uncertainty in the fraction of the $\delta$-phase hydride. In addition, significant efforts are being dedicated to establish a complete database summarizing the thermomechanical and physical properties of as-fabricated yttrium hydride and the irradiation response to facilitate its deployment as a high-temperature moderator in advanced nuclear reactors.

鉴于出色的热稳定性和高度可获得的氢密度，氢化钇是需要小堆芯体积的先进热中子能谱反应堆中的一种出色的高温调节剂。大规模，无裂纹的块状氢化钇需求量很大。然而，氢化钇的制备具有挑战性，并且已经有近半个世纪没有得到证明。本文讨论了相关的挑战。为了应对这些挑战，在橡树岭国家实验室设计并制造了一种氢化系统，该系统用于成功地大规模制造复杂几何形状的无裂纹的氢化钇。这是通过精确控制氢的分压和the的温度来实现的，这是由于已建立的二元H-Y系统的热力学性质所致。人造氢化物中的氢含量是通过重量变化来确定的，该方法被认为是可靠的方法，基于超高纯钇的使用，不存在氧化物相直至使用X射线衍射（XRD）可以检测到的水平，以及体重明显增加。通过XRD分析，评估了从一根氢化钇棒上氢的分布，这些材料是从棒上不同位置提取的。结果表明，沿着氢化物棒的氢分布相对均匀，不确定度小于3％。没有氧化物相达到使用X射线衍射（XRD）可以检测到的水平，而且重量增加显着。通过XRD分析，评估了从一根氢化钇棒上氢的分布，这些材料是从棒上不同位置提取的。结果表明，沿着氢化物棒的氢分布相对均匀，不确定度小于3％。没有氧化物相达到使用X射线衍射（XRD）可以检测到的水平，而且重量增加显着。通过XRD分析，评估了从一根氢化钇棒上氢的分布，这些材料是从棒上不同位置提取的。结果表明，沿着氢化物棒的氢分布相对均匀，不确定度小于3％。$\delta$相氢化物。此外，正致力于建立一个完整的数据库，以汇总已制成的氢化钇的热机械和物理特性以及辐射响应，以促进其在先进核反应堆中作为高温调节剂的应用。