Abstract Savannah River Tritium Enterprise (SRTE) has used LaNi4.25Al0.75 (LANA75) hydride beds to store hydrogen isotopes for over two decades. A benefit of using LANA75 is that the 3He generated from tritium decay is retained in the hydride material, allowing the hydride beds to deliver high-purity product gas. A disadvantage is that the 3He accumulates in the LANA75 material over time, which forms a heel that cannot be removed under normal operating conditions. The heel traps hydrogen in the bed, slowly reducing the operational capacity of the bed as the heel grows. Eventually, the 3He begins to release from the material, preventing the delivery of high-purity product. The hydride beds are replaced when (1) operational capacity is reduced such that it is impactive to routine operations and/or (2) product purity is not maintained due to 3He release. Prior to replacing and disposing of the beds, it is necessary to isotopically exchange the gas on the bed to recover as much tritium as possible. Isotopic exchange involves repeatedly absorbing deuterium onto the bed and desorbing hydrogen isotopes from the bed until a predetermined criterion has been met. The isotopic exchange process represents a significant additional load on routine operations both in time and in the amount of waste gas that requires further processing. A set of beds was recently prepared for replacement. The isotopic exchange method used by SRTE is presented, along with results of the most recent isotopic exchange. Lessons learned during the recent isotopic exchange process led to modifications that reduce isotopic exchange duration and corresponding waste gas produced while increasing the amount of tritium recovered.

中文翻译：

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氢化物床同位素交换

摘要 萨凡纳河氚企业 (SRTE) 使用 LaNi4.25Al0.75 (LANA75) 氢化物床来储存氢同位素已超过二十年。使用 LANA75 的一个好处是氚衰变产生的 3He 保留在氢化物材料中，使氢化物床能够提供高纯度的产品气体。一个缺点是 3He 会随着时间的推移在 LANA75 材料中积累，从而形成在正常操作条件下无法去除的跟部。跟部将氢气捕获在床中，随着跟部的增长，床的运行能力逐渐降低。最终，3He 开始从材料中释放出来，阻止了高纯度产品的交付。当 (1) 操作能力降低从而影响常规操作和/或 (2) 由于 3He 释放而无法保持产品纯度时，更换氢化物床。在更换和处置床层之前，必须对床层上的气体进行同位素交换，以尽可能多地回收氚。同位素交换包括反复将氘吸收到床上并从床上解吸氢同位素，直到满足预定标准。同位素交换过程在时间和需要进一步处理的废气量方面对常规操作造成了显着的额外负担。最近准备了一套床来更换。介绍了 SRTE 使用的同位素交换方法，以及最近的同位素交换结果。