Study of multi-column cold trap with highly effective recovery rate of tritium water vapor

建立聚变反应堆的氚安全约束和燃料处理回路是聚变反应堆研究的重要课题之一。在传统的应急氚封隔工艺中，催化氧化和沸石吸附是主要工艺。虽然该工艺能满足日本设施处理放射性同位素的安全要求，但吸附剂间隙中氚的去除非常困难，因此存在氚库存增加的缺点。因此，有必要对传统的催化氧化-水吸附工艺进行改进，以实现对氚气体和氚化合物的更高安全限制，而聚酰亚胺气体分离膜可使处理气体量大大减少，从而简化工艺流程。本研究建立了一个实验装置，在不使用任何吸附剂的情况下，可以将水蒸气去除到环境中氚化合物的规定水平以下。 关于我们 为了将氚水蒸气回收到规定水平，必须解决冷阱的氚穿透和管道表面沉积堵塞问题。在本研究的第一年，我们发现氚突破是由均匀成核下的雾产生引起的。随着两级冷却系统的设置，我们成功地运行它没有雾的形成，在表面上的结霜率的定量估计，因此窒息的时间，最后在氚去除率的总体估计。在第二年，我们进行了两级除氚系统的实验，该系统包括一个由干冰冷却的开放式柱阱和一个由液氮冷却的玻璃填充冷阱串联。实验结果发表在《分离科学与技术》等国际期刊上。我们成功地进行了ITER级聚变反应堆除氚系统的优化设计。少

It is one of the most important issues to establish processes for tritium safety confinement and a fuel processing loop of a fusion reactor. In conventional processes for the emergency tritium confinement, catalytic oxidation and zeolite adsorption was the main process. Although the process can satisfy the safety rule for handling radioisotopes in Japanese facilities, the removal of tritium in interstitial sites of adsorbent was very difficult, and so it had a disadvantage of an increasae in tritium inventry. Therefore, it is necessary to improve the conventional catalytic oxidation and water adsorption process for the higher safety confinement of tritium gas and tritium compounds.The polyimede gas separation membrane can make gas volume processed decrease greatly and so make the process simple. In the present study we set up an experimental apparatus which can remove water vapor down to lower than the regulation level of tritium compounds in the environment without any use of adsorben … More t.In order to recover tritium water vapor down to the regulation level it was necessary to solve the problems of the tritium breakthrough of the cold trap and duct choking by deposition on the surfaces. In the first year of the present research, we found out that the tritium breakthrough was caused by mist generation under homogeneous nucleation. With the setup of a two-stages cooling system, we succeeded in operating it without mist formation, in quantitative estimation of frost formation rate on surfaces and so the time of choking, and finally in overall estimation of tritium removal rate. In the second year, we carried out experiments of the two stages tritium removal system comprising an open-column trap cooled by dry ice and glass-packed cold trap cooled by liquid nitrogen in series. The experimental results were presented in international journals such as Separation Science and Technology. We succeeded in the optimal design of the tritium removal system for an ITER-scale fusion reactor. Less