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Innovation in the Design of Improved Actinide Selective Extractants Suitable for use in Large Scale Spent Nuclear Fuel Reprocessing

适用于大规模乏核燃料后处理的改进锕系元素选择性萃取剂的设计创新

基本信息

批准号：
EP/P004873/1
负责人：
Frank Lewis
金额：
$ 12.83万
依托单位：
Northumbria University
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2017
资助国家：
英国
起止时间：
2017 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FP004873%2F1
关键词：
Innovation Design Improved Actinide Selective

项目摘要

A key challenge that needs to be overcome in spent nuclear fuel reprocessing is to separate the radiotoxic minor actinides from the non-radiotoxic lanthanides. Extracting and separating these elements from the lanthanides after the 'Plutonium and URanium EXtraction' (PUREX) process will reduce the long lived radiotoxicity of the remaining spent fuel and enable these elements to be rendered safe by transmutation (high energy neutron bombardment) or used as fuel in advanced GenerationIV reactors. This separation is critical because the lanthanides have higher neutron capture radii than the actinides and would thus prevent the neutron chain reaction that would render the actinides safe. Three families of N-donor ligand containing the 1,2,4-triazine moiety have been developed that can extract and separate the minor actinides from the lanthanides with very high selectivity. These are known as bistriazinylpyridines (BTPs), bistriazinylbipyridines (BTBPs) and bistriazinylphenanthrolines (BTPhens). However, whilst these ligands fulfill many of the requirements for use in a 'Selective ActiNide EXtraction' (SANEX) separation process, two main limitations remain to be overcome prior to industrial scale use:1. Their limited solubility range in solvents acceptable to the nuclear industry (typically less than 10 mM). 2. Their relatively slow rates of extraction.To the best of our knowledge, there has been no research on the exploration of other N-donor ligand families containing the crucial 1,2,4-triazine moiety. Furthermore, the application of an innovative approach to improving the above limitations has not previously been carried out. This research proposal aims to investigate new families of N-donor ligand based on the 1,2,4-triazine moiety for the selective extraction of actinides over lanthanides. This will advance the fields of spent nuclear fuel reprocessing and radioactive waste management, with the potential for the ligands to be used by the nuclear industry in future large-scale actinide-lanthanide separation processes that will underpin the current resurgence in nuclear energy. If successful, this proposed research would expand the scope of currently available ligands for use in the processing of spent nuclear fuel and provide one or more lead structures with improved solvent extraction properties suitable for future industrial use. The novelty of the proposed approach lies in (i) Synthesis of new ligand families that have never been explored previously for the separation of actinides from lanthanides. (ii) The application of an innovative approach to ligand design that addresses the two most critical shortcomings of existing 1,2,4-triazine based ligands; low solubilities and slow rates of extraction. This innovative approach is inspired by those aspects of drug discovery that specifically relate to solubility and polarity (which can influence surface concentration at an organic/aqueous interface and hence extraction kinetics). The research is timely because, after several decades of decline in the UK and worldwide, nuclear energy is experiencing a resurgence in fortunes (the 'nuclear renaissance') and several countries (including the UK) have announced plans for new reactor build. This means the volume of spent nuclear fuel will continue to increase in future. However, no process is currently available to render this material safe for geological disposal. Thus it is even more important to develop a feasible selective actinide extraction process in the near future. The project includes two academic collaborators who have extensive expertise in performing solvent extraction measurements on ligands using radionuclides, and developing novel selective actinide extraction processes. The project also includes one industrial collaborator who has expertise in the commercialization and exploitation of new technology and products, and who already markets a range of ligands to the global nuclear industry.

在乏核燃料后处理中需要克服的一个关键挑战是将具有放射性毒性的次要元素与非放射性的稀土元素分开。在“钚和铀提取”(Purex)过程之后，从稀土元素中提取和分离这些元素将降低剩余乏燃料的长期放射性毒性，并使这些元素能够通过变形(高能中子轰击)变得安全，或用作先进的第四代反应堆的燃料。这种分离是至关重要的，因为镧系元素的中子俘获半径比放线系元素高，因此会阻止使元素元素变得安全的中子链反应。合成了三类含1，2，4-三氮杂环的N-给体配体，可以很高的选择性地从稀土元素中提取和分离出次要元素。这些化合物被称为双三嗪基吡啶(BTP)、双三嗪基联吡啶(BTBPs)和二氮杂菲咯啉(BTPhens)。然而，尽管这些配体满足了用于“选择性萃取”(SANEX)分离过程的许多要求，但在工业规模使用之前仍有两个主要限制需要克服：1.它们在核工业可接受的溶剂中的溶解范围有限(通常小于10 mM)。2.它们的抽提速度相对较慢。据我们所知，还没有关于含有关键的1，2，4-三嗪部分的其他N-供体配体家族的探索的研究。此外，以前还没有采用创新的方法来改善上述限制。本研究的目的是研究基于1，2，4-三氮杂环的新型N-供体配体家族，用于在稀土元素的基础上选择性地萃取放线系元素。这将推动乏核燃料后处理和放射性废物管理领域的发展，核工业有可能在未来的大规模榄系元素-稀土元素分离过程中使用这些配体，这将为目前核能的复苏奠定基础。如果成功，这项拟议的研究将扩大目前可用于处理乏核燃料的配体的范围，并提供一个或多个铅结构，其溶剂提取性能得到改善，适合未来的工业使用。该方法的创新之处在于：(I)合成了以前从未探索过的新的配体家族，用于从镧系元素中分离吖系元素。(2)采用一种创新的方法进行配体设计，以解决现有1，2，4-三嗪类配体的两个最严重的缺点：溶解度低和提取速度慢。这一创新方法的灵感来自于药物发现中与溶解度和极性有关的那些方面(这可能会影响有机/水界面的表面浓度，从而影响提取动力学)。这项研究是及时的，因为在英国和世界范围内经历了几十年的衰落之后，核能正在经历命运的复兴(核能复兴)，而且几个国家(包括英国)已经宣布了建造新反应堆的计划。这意味着未来乏核燃料的数量将继续增加。然而，目前还没有任何工艺可以使这种材料安全地进行地质处置。因此，在不久的将来，开发一种可行的、选择性的鳗系元素提取工艺就变得更加重要。该项目包括两名学术合作者，他们在使用放射性核素对配体进行溶剂提取测量和开发新的选择性榄系元素提取工艺方面拥有丰富的专业知识。该项目还包括一名工业合作者，他在新技术和产品的商业化和开发方面拥有专业知识，并已向全球核工业营销一系列配体。