Abstract

Electrolysis cells are required to drive the combined electrolysis and catalytic exchange process used in heavy water upgrading and water detritiation.

Past projects have used very robust alkaline electrolyte technology for the electrolysis cells, though recently there has been a move toward proton exchange membrane (PEM) technology. In PEM electrolysis a solid polymer electrolyte (SPE) acts as the proton conductor, separator of product gases, and insulator between electrodes.

The long-term effects of highly tritiated water on these SPE materials are not fully understood. At Canadian Nuclear Laboratories (CNL), an exposure study has been undertaken wherein various commercial and proprietary SPE materials were exposed to very highly tritiated water (~1000 Ci/kg, 37 TBq/kg). Exposures were done at a typical cell operating temperature (60°C) for periods that might be expected for commercial operations.

Following exposure, some samples lost sufficient integrity that they could not undergo post-exposure testing. In order to test the remaining materials’ electrolytic performance and physical properties in a nonactive laboratory, a process of decontamination that would result in no further membrane degradation needed to be developed. The successful reduction in tritium content of the samples following decontamination was verified using chemical digestion and combustion analysis. All types of commercial membranes were found to lose significant ion exchange capacity, to show reduced water absorption, and to show reduced strain before failure. Tensile testing showed almost complete degradation even at low doses. In this paper, commercial membrane data are compared with data from CNL’s tritium-compatible membranes.

摘要

需要电解池来驱动用于重水提质和水净化的综合电解和催化交换过程。

过去的项目已将非常坚固的碱性电解质技术用于电解槽，尽管最近已向质子交换膜（PEM）技术迈进。在PEM电解中，固态聚合物电解质（SPE）充当质子导体，产物气体的分离器以及电极之间的绝缘体。

高度tri水对这些SPE材料的长期影响尚未完全了解。在加拿大核实验室（CNL）进行了一项暴露研究，其中将各种商业和专有SPE材料暴露于高度tri化的水中（〜1000 Ci / kg，37 TBq / kg）。在典型的电池工作温度（60°C）下进行暴露，这可能是商业运行所预期的。

暴露后，一些样品失去了足够的完整性，无法进行暴露后测试。为了在非活性实验室中测试剩余材料的电解性能和物理性能，需要开发一种不会导致进一步膜降解的去污方法。使用化学消解和燃烧分析验证了净化后样品中successful含量的成功降低。发现所有类型的商业膜都失去了显着的离子交换能力，显示出降低的吸水率，并显示出破坏前的应变降低。拉伸试验显示即使在低剂量下也几乎完全降解。在本文中，将商业膜数据与CNL compatible兼容膜的数据进行了比较。