Radionuclide Capture Techniques for Nuclear Operations and Decommissioning

加拿大的几个核电厂要么正在开始退役进程，要么正在准备退役(核电示范工厂，Gentilly1，Gentilly2，Pickering 1-8)，其中包括结构、系统和部件的去污和拆除，在长期处置设施中处置活性废物，以及场地的补救。工程的规模约为数十亿美元。其他国家，如美国和日本，在退役过程中走得更远，目前可用的大部分技术将来自加拿大以外的国家。虽然这项技术确实存在，但其中很大一部分是基于比加拿大许可高出25倍的许可限制。因此，这些技术的应用对加拿大来说可能不具有成本效益，并且/或者可能由于产生二次污染/废物(通过气雾剂、粉尘产生、废水等)而对环境造成更大的负担。去污效果由去污系数(DF)决定，去污系数等于初始活性/最终活性。由于加拿大的通关水平较低，df可能需要在100或更高的范围内，而大多数可用的技术提供df在4-20的范围内。这意味着，去污可能对设施的大部分没有用处，大多数材料将需要运往核废料处置场(目前没有)，而不是被回收。这项研究有两个主要主题：辐射源的识别和辐射源的捕获。在第一个主题中，研究将考虑目前可能产生二次废物(含有放射性核素颗粒的气雾剂)的拆除技术。确定二次废物的性质很重要，因为存在清理二次废物和以潜在较低成本实现更大环境保护的潜力。在第二个主题中，凝胶以及使用电流体和等离子体过程来清洁材料和捕获辐射将是探索不同应用的关键方法。这项工作需要延长，以确定这些技术对其他潜在放射性物种，如铯、铁、氚和氯的有效性。这项研究将考虑各种因素，如表面条件、环境条件、粉尘负荷、物种浓度和化学反应可能如何影响特定物种的捕获效率。其目的是开发具有高去污系数的技术，或可与现有技术相结合的技术，以提高放射性核素捕获的净效率。这项研究将确定将满足加拿大保护环境需求的改进措施。这项研究将帮助加拿大公司发展自己的退役能力，并减少对外国公司的依赖。

Several nuclear power plants in Canada are either starting the decommissioning process or are in preparation for decommissioning (Nuclear Power Demonstration Plant, Gentilly1, Gentilly2, Pickering 1-8) which covers the decontamination and dismantling of structures, systems and components, the disposal of active waste in long term disposal facilities and remediation of the site. The scope of work is on the order of several billion dollars. Other countries, such as the United States and Japan, are farther along in the decommissioning process and most of the technologies currently available will come from outside Canada. While the technology does exist, much of that technology is based upon clearance limits that are 25 times higher than Canada permits. As such, the application of those technologies may not be cost effective for Canada and/or may introduce a higher burden on the environment due to the generation of secondary contamination/waste (through aerosol, dust generation, effluents, etc.). Decontamination effectiveness is determined by the Decontamination Factor (DF) which equals initial Activity/final Activity. Due to Canada's low clearance levels, the DF may need to be in the range of 100 or higher whereas most available techniques provide DF in the range of 4-20. This means that decontamination may not be useful for most of the facility and the majority of the material will need to go to a nuclear waste disposal site (which is currently not available) as opposed to being recycled. This research has two main themes: identification of radiation sources and capture of those radiation sources. In the first theme, the research will consider current dismantling techniques that may generate secondary wastes (aerosols containing radionuclide particles). The nature of the secondary waste is important to identify as the potential exists to clean the secondary waste and achieve greater environmental protection at potentially lower costs. In the second theme, gels and the use of the electrohydrodynamic and plasma processes to clean material and capture the radiation will be a key method to explore for the different applications. The work needs to be extended to determine the effectiveness of these techniques for other potentially radioactive species such as Cesium, Iron, Tritium, and Chlorine. The research will consider how various factors such as surface conditions, environment conditions, dust loads, species concentration, and chemical reactions may affect the capture efficiency of a given species. The intent is to develop techniques with high decontamination factors or techniques that can be combined with existing techniques to improve the net efficiency of radionuclide capture. This research will identify improvements that will meet Canada's needs for protecting the environment. The research will assist Canadian Companies with developing their own capabilities in decommissioning and reduce reliance on foreign companies.