Programa Nacional de Gestión de Residuos Radiactivos, Comisión Nacional de Energía Atómica, Centro Atómico Constituyentes, Av. General Paz 1499, 1650, San Martín, Buenos Aires, Argentina.
Escuela de Ciencia y Tecnología, Universidad Nacional de General San Martín, Campus Miguelete, Martín de Irigoyen 3100, 1650, San Martín, Argentina.
Environ Sci Pollut Res Int. 2018 Aug;25(22):21403-21410. doi: 10.1007/s11356-017-8766-2. Epub 2017 Mar 23.
Polystyrene divinylbenzene-based ion exchange resins are employed extensively within nuclear power plants (NPPs) and research reactors for purification and chemical control of the cooling water system. To maintain the highest possible water quality, the resins are regularly replaced as they become contaminated with a range of isotopes derived from compromised fuel elements as well as corrosion and activation products including C, Co, Sr, I, and Cs. Such spent resins constitute a major proportion (in volume terms) of the solid radioactive waste generated by the nuclear industry. Several treatment and conditioning techniques have been developed with a view toward reducing the spent resin volume and generating a stable waste product suitable for long-term storage and disposal. Between them, pyrolysis emerges as an attractive option. Previous work of our group suggests that the pyrolysis treatment of the resins at low temperatures between 300 and 350 °C resulted in a stable waste product with a significant volume reduction (>50%) and characteristics suitable for long-term storage and/or disposal. However, another important issue to take into account is the complexity of the off-gas generated during the process and the different technical alternatives for its conditioning. Ongoing work addresses the characterization of the ion exchange resin treatment's off-gas. Additionally, the application of plasma technology for the treatment of the off-gas current was studied as an alternative to more conventional processes utilizing oil- or gas-fired post-combustion chambers operating at temperatures in excess of 1000 °C. A laboratory-scale flow reactor, using inductively coupled plasma, operating under sub-atmospheric conditions was developed. Fundamental experiments using model compounds have been performed, demonstrating a high destruction and removal ratio (>99.99%) for different reaction media, at low reactor temperatures and moderate power consumption. The role of HO as an important participant of the oxidation mechanisms in plasma conditions was established. The combination of both processes could represent a simple, safe, and effective alternative for treating spent ion exchange resins with a large reduction of generated gaseous byproducts in fuel cycle facilities where processes that utilize open flames are undesirable.
聚苯乙烯二乙烯基苯基离子交换树脂在核电站 (NPP) 和研究反应堆中被广泛用于净化和化学控制冷却水系统。为了保持尽可能高的水质，当树脂被来自受损燃料元件以及腐蚀和激活产物（包括 C、Co、Sr、I 和 Cs）的一系列同位素污染时，它们会定期更换。这些用过的树脂构成了核工业产生的固体废物中主要的一部分（按体积计算）。已经开发了几种处理和调节技术，旨在减少废树脂的体积并生成一种稳定的废物产品，适合长期储存和处置。其中，热解作为一种有吸引力的选择脱颖而出。我们小组之前的工作表明，在 300 至 350°C 的低温下对树脂进行热解处理，可生成一种具有显著体积减少（>50%）和适合长期储存和/或处置的稳定废物产品。然而，另一个需要考虑的重要问题是过程中产生的废气的复杂性以及对其调节的不同技术选择。正在进行的工作涉及对离子交换树脂处理废气的特性进行表征。此外，等离子体技术在处理废气方面的应用也作为替代传统工艺的方法进行了研究，这些传统工艺使用在 1000°C 以上温度运行的油或燃气后燃烧室。开发了一种使用感应耦合等离子体的实验室规模流动反应器，在亚大气压条件下运行。使用模型化合物进行了基础实验，结果表明，在低温和中等功率消耗下，对于不同的反应介质，都具有很高的破坏和去除率（>99.99%）。建立了 HO 在等离子体条件下氧化机制中重要参与者的作用。这两个过程的结合可能代表了一种简单、安全和有效的替代方法，用于处理在不希望使用明火工艺的燃料循环设施中产生的大量气态副产物的用过的离子交换树脂。
