Abstract Hydride beds containing LaNi4.25Al0.75 (LANA.75) are used to store significant quantities of tritium. These hydride beds have a limited service life due to radiolytic decay of tritium to 3He within the metal matrix. The crystal structure of the hydride is altered by trapped 3He, which has a very low solubility in the metal. The altered structure induces the formation of a heel of trapped hydrogen isotopes and diminishes the reversible capacity of the hydride. With sufficient tritium exposure, the bed loses the ability to deliver 3He-free tritium, and replacement is needed. Demonstration of a means to regenerate tritium-aged LANA.75 in situ would delay or even eliminate the need to replace lanthanum nickel aluminum (LANA) hydride beds. This paper presents test results obtained during regeneration testing. The efficacy of regeneration testing was evaluated by comparing tritium desorption isotherms collected on the hydride before and after exposure to regeneration conditions. Testing was performed on a bench-scale tritium-aged LANA.75 sample that was previously isotopically exchanged (from tritium to deuterium), passivated, and recovered. Once transferred to a high-temperature test cell, the deuterium heel of the sample was isotopically exchanged with tritium, and a baseline desorption isotherm was collected for comparison purposes. The sample was then heated under vacuum, and comparative isotherms were gathered between regeneration evolutions. Shifts in isotherms show progressive improvements with higher-temperature exposure over the tritium-aged baseline. The heel was significantly reduced, and the reversible capacity of the hydride was essentially restored to near virgin values. For all tested conditions, the plateau pressure remained higher than virgin LANA.75.

中文翻译：

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氚时效 LaNi4.25Al0.75 样品的性能恢复

摘要 含有 LaNi4.25Al0.75 (LANA.75) 的氢化物床被用来储存大量的氚。由于氚在金属基体内辐射分解为 3He，这些氢化物床的使用寿命有限。氢化物的晶体结构被捕获的 3He 改变，它在金属中的溶解度非常低。改变的结构导致形成大量被捕获的氢同位素并降低氢化物的可逆容量。接触足够的氚时，床将失去输送不含 3He 的氚的能力，需要更换。展示一种原位再生氚老化 LANA.75 的方法将延迟甚至消除更换镧镍铝 (LANA) 氢化物床的需要。本文介绍了在再生测试过程中获得的测试结果。通过比较在暴露于再生条件之前和之后在氢化物上收集的氚解吸等温线来评估再生测试的功效。测试是在实验室规模的氚老化 LANA.75 样品上进行的，该样品之前进行了同位素交换（从氚到氘）、钝化和回收。转移到高温测试池后，样品的氘尾与氚进行同位素交换，并收集基线解吸等温线以进行比较。然后在真空下加热样品，并在再生演变之间收集比较等温线。等温线的变化表明随着更高温度暴露在氚老化基线上的逐步改善。脚后跟明显缩小，并且氢化物的可逆容量基本上恢复到接近原始值。对于所有测试条件，平台压力仍然高于原始 LANA.75。