Abstract In order to ensure the efficient management of radioactive waste in the form of tritiated light water and tritiated heavy water with low tritium and/or deuterium concentration, Institute for Cryogenics and Isotopic Technologies (ICSI) Rm.Valcea is developing an experimental demonstration facility based on the combined electrolysis catalytic exchange (CECE) separation process. The facility is completing the experimental pilot plant for tritium and deuterium separation—the installation support for heavy water detritiation from the CANDU reactors in Romania. The concentration of deuterium from low-concentrated waste extends the recovery area from below 1% D2O/(D2O + H2O), corresponding to the minimum threshold of the Cernavoda Upgrading Facility, thus contributing to the reduction of heavy water losses. At the same time the tritium recovery process will be increased. The experimental installation has an innovative solution that reconfigures a proton exchange membrane (PEM) electrolyzer for tritium qualification thereby improving equipment specific to hydrogen isotope separation processes. This paper presents the experimental installation conceptual scheme, including the measurement and control elements. A modeling software for simulation of the nonsteady-state regime of the CECE separation process, specific to the deuterium/tritium isotopes concentration process in the liquid phase, is also presented. The mathematical model integrates the characteristic equations of separation by liquid phase catalytic exchange (LPCE), the mathematical representation of isotope separation by electrolysis, and the water distillation from the oxygen purification process in a nonstationary regime. An analysis is presented for the concentration of various low-concentrated tritium waste. We also investigate the influence of the electrolyzer liquid holdup and the isotopic separation column holdup on concentrated water production.

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实验阶段前低氚化废液的CECE工艺研究

摘要 为了确保氚化轻水和氚化和/或氘浓度低的氚化重水形式的放射性废物的有效管理，低温和同位素技术研究所 (ICSI) Rm.Valcea 正在开发一个基于联合电解催化交换（CECE）分离工艺。该设施正在完成氚和氘分离的实验性试验工厂——罗马尼亚坎杜反应堆重水脱氚的安装支持。低浓度废物中的氘浓度将回收范围从低于 1% D2O/(D2O + H2O)，对应于切尔纳沃达升级设施的最低阈值，从而有助于减少重水损失。同时氚回收过程将增加。实验装置具有创新的解决方案，可重新配置质子交换膜 (PEM) 电解槽以进行氚鉴定，从而改进特定于氢同位素分离过程的设备。本文介绍了实验安装概念方案，包括测量和控制元件。还介绍了一种建模软件，用于模拟 CECE 分离过程的非稳态状态，特别是液相中的氘/氚同位素浓缩过程。数学模型综合了液相催化交换（LPCE）分离的特征方程、电解分离同位素的数学表示、以及在非平稳状态下来自氧气净化过程的水蒸馏。对各种低浓度氚废物的浓度进行了分析。我们还研究了电解槽液体滞留量和同位素分离塔滞留量对浓水生产的影响。