Development of Novel Treatments for Carbon-based radioactive wastes

过去70年的核能和核武器方案在世界各地造成了废物和污染。在这些方案产生的各种各样的复杂废物中，有一系列“孤儿”废物。这些废物不适合在现有的加工厂处理，目前也没有公认的处理办法，本项目将确定处理无主放射性废物的全新办法的可行性。总体的长期研究愿景是一个三阶段的废物处理过程。首先，将废物闷烧（与煤在火中闷烧的方式相同）以燃烧碳并产生少量稳定的放射性灰烬，这些灰烬可以被封装（通常在水泥中）并放入容器（由钢或混凝土组成）中，以便将来进行地质处置。第二，安全地捕获由阴燃过程释放的放射性排放物。这些是以放射性核素和二氧化碳气体的微观颗粒的形式存在的，其中含有放射性元素碳14。这种捕获将利用与正在探索的从大气中去除二氧化碳以应对气候变化的技术类似的技术。细菌将用于刺激碳酸盐和/或磷酸盐矿物的生产，从气体中去除放射性并将其捕获到稳定的矿物中（即进入岩石中）。最后，将放射性捕获到矿物中的过程将作为放射性灰的包封过程的一部分进行，（在将其放入容器之前）或其他放射性废物，以减少需要处置的放射性物质的最终体积。为了使孤儿废物的任何处理过程得到联合王国监管当局的接受，关键是不排放放射性气体。因此，本研究项目将重点展示（1）将14 C作为稳定的碳酸盐捕获的可行性，以及（2）将其他颗粒放射性排放物捕获到稳定的磷酸盐矿物中的可行性。该项目将侧重于证明石墨这一单一废物形式的可行性，石墨是体积最大的孤儿废物。如果可行性得到证明，将开展其他研究项目，探索阴燃过程以及使用碳酸盐和磷酸盐矿物封装阴燃过程产生的放射性灰烬。

The nuclear energy and weapons programmes of the past 70 years have created a legacy of waste and contamination around the world. Amongst the very diverse and complicated wastes arising from these programmes are a range of "orphan" wastes. These are wastes which are not suitable for treatment in existing processing plants and for which there is no currently accepted treatment option.This project will determine the feasibility of a wholly new approach to treatment of orphan radioactive wastes. The overarching longer-term research vision is for a three-stage waste treatment process. First, smouldering the waste (in the same way that coal smoulders in a fire) to burn the carbon and produce a small volume of stable radioactive ash that can be encapsulated (generally in cement) and placed into a container (comprised of steel or concrete) for future geological disposal. Second, capturing safely the radioactive emissions that are released by the smouldering process. These are in the form of microscopic particles of radionuclides and carbon dioxide gas that contains the radioactive element, Carbon 14. This capture will make use of similar technologies to those being explored to remove carbon dioxide from the atmosphere to tackle climate change. Bacteria will be used to stimulate the production of carbonate and/or phosphate minerals, removing the radioactivity from the gases and capturing them into a stable mineral (i.e. into a rock) . Finally, this process of capturing the radioactivity into a mineral will be performed as part of the encapsulation process either for the radioactive ash (prior to placing it in a container) or for other radioactive wastes, so as to reduce the final volume of radioactive material that requires disposal.In order for any treatment process of orphan wastes to be accepted by the UK regulatory authorities, it is critical that no radioactive gases are emitted. Hence, this research project will focus on demonstrating the feasibility of capturing (1) 14C as a stable carbonate and (2) other particulate radioactive emissions into stable phosphate minerals. The project will focus on demonstrating feasibility for a single wasteform, graphite, which is the largest volume orphan waste. If feasibility can be demonstrated, other research projects will follow to explore the smouldering process and the use of the carbonate and phosphate minerals for encapsulation of the radioactive ashes, created by the smouldering process.