Study on basic characteristics of hollow filament polyimide membrane in tritium separation and its application to tritium monitors

为了建立加速器束线隧道通过堆释放空气中氚的监测方法，提出了一种采用顺丝聚酰亚胺膜作为气体分离装置的新型实时连续气体监测系统，并对膜的基本气体分离特性进行了实验研究。特别是对干空气中氮和水中氢同位素的分离特性进行了广泛的测量，并采用简化的横流模型进行了气体分离的计算机模拟。结果表明，聚酰亚胺膜组件能显著富集氮和干空气中的氢同位素和水蒸气，对氢同位素（H2和D2）的分离特性没有明显的同位素效应。结果表明，该膜可用于氚的实时监测。并提出了氚监测系统的概念设计。本研究的结果已在若干国际会议上发表，并发表在期刊上。

In order to establish monitoring method of tritium in air released from accelerator beam-line tunnels through the stacks, a new real-time continuous gas monitoring system using a follow-filament polyimide membrane as a gas-separation device, has been proposed and basic gas-separation characteristics of membranes have been investigated experimentally in this study. Especially, the separation characteristics of hydrogen isotopes in nitrogen and water in dry-air were measured extensively, and a computer simulation using the simplified cross-flow model for the gas separation was also performed. The result showed that the polyimide membrane module could enrich significantly hydrogen isotopes and water vapor from nitrogen and dry air, and there were not observed remarkable isotope effects in separation characteristics between hydrogen isotopes (H2 and D2). It can be concluded from these results that the membrane is useful for the real time tritium monitoring. A conceptual design of a tritium monitoring system in also proposed. The results obtained in this study were presented at the several international conferences/meetings and were published in the journals.