Development of Novel Treatments for Carbon-based radioactive wastes

过去70年的核能和核武器计划在全世界造成了废物和污染的遗留问题。在这些计划产生的非常多样和复杂的废物中，有一系列“孤儿”废物。这些废物不适合在现有的加工厂进行处理，目前也没有可接受的处理方案。这个项目将确定采用一种全新方法处理放射性废物的可行性。总体的长期研究愿景是一个三阶段的废物处理过程。首先，阴燃废物（与煤在火中阴燃的方式相同）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）以备将来的地质处置。第二，安全捕获闷烧过程中释放的放射性排放物。它们以放射性核素的微观颗粒和含有放射性元素碳14的二氧化碳气体的形式存在。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为稳定的矿物（即岩石）。最后，这种将放射性捕获到矿物中的过程将作为放射性灰（在将其放入容器之前）或其他放射性废物的封装过程的一部分进行，以便减少需要处理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被英国监管当局所接受，不排放放射性气体是至关重要的。因此，本研究项目将重点展示捕获(1)14C作为稳定碳酸盐和(2)其他颗粒放射性排放物到稳定磷矿物中的可行性。该项目将重点展示一种单一废物形式石墨的可行性，石墨是体积最大的孤儿废物。如果能够证明可行性，其他研究项目将随后探索闷烧过程和使用碳酸盐和磷酸盐矿物来封装由闷烧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.