Recent interest in U₃Si₂ as an advanced light water reactor fuel has driven assessment of numerous properties, but characterization of its response to H₂O environments is sparse in available literature. The behavior of U₃Si₂ in H₂O containing atmospheres is investigated and presented in a two-part series of articles. This work examines the behavior of U₃Si₂ following exposure to pressurized H₂O at temperatures from 300 to 350 °C. Testing was performed using two autoclave configurations and multiple redox conditions. Use of solid state buffers to attain a controlled water chemistry is also presented as a means to test actinide-bearing systems. Buffers were used to vary the hydrogen concentration between 1 and 30 parts per million H₂. Testing included UN, U₃Si₅, and UO₂. Both UN and U₃Si₅ were found to rapidly pulverize in less than 50 h at 300 °C. Uranium dioxide was included as a control for the autoclave system, and was found to be minimally impacted by exposure to pressurized water at the conditions tested for extended time periods. Testing of U₃Si₂ at 300 °C found reasonable stability through 30 days in 1–5 ppm H₂. However, pulverization was observed following 35 days. The redox condition of testing strongly affected pulverization. Characterization of the resulting microstructures suggests that the mechanism responsible for pulverization under more strongly reducing conditions differs from that previously identified. Hydride formation is hypothesized to drive this transition. Testing performed at 350 °C resulted in rapid pulverization of U₃Si₂ in under 50 h.

U ₃ Si ₂作为一种先进的轻水反应堆燃料的最新兴趣推动了许多性能的评估，但是在现有文献中稀少地描述了其对H ₂ O环境的响应。对U ₃ Si ₂在含H ₂ O的气氛中的行为进行了研究，并分为两部分进行了介绍。这项工作检查了U ₃ Si ₂在暴露于加压H _{2后的行为}O在300至350°C的温度下。使用两个高压釜配置和多个氧化还原条件进行测试。还提出了使用固态缓冲剂来实现受控的水化学反应，作为测试含act系元素的系统的方法。使用缓冲液在百万分之一H _2的1至30份之间改变氢气浓度。测试包括UN，U ₃ Si ₅和UO ₂。发现UN和U ₃ Si ₅在300°C下可在不到50 h的时间内迅速粉碎。包括二氧化铀作为高压釜系统的对照，发现在长时间测试的条件下，暴露于加压水中对铀的影响最小。U _3的测试Si ₂在300°C的条件下在1-5 ppm H _2中经过30天才发现合理的稳定性。然而，在35天后观察到粉化。测试的氧化还原条件强烈影响粉化。所得微结构的表征表明，在更强烈的还原条件下负责粉碎的机理与先前确定的机理不同。假设形成氢化物以驱动该转变。在350°C下进行的测试导致U ₃ Si ₂在50小时内迅速粉碎。