Novel restoration materials for clean-up of radionuclides in the environment

尽管日本在处理福岛第一核电站(FDNPP)事故的影响方面做出了巨大的技术和财政努力，但仍然存在许多挑战。日本政府污水处理对策委员会审议了现有和拟议的措施和技术，以“清除”受污染的水，防止“水流入污染源”，并“防止”受污染的水泄漏到环境中。他们在2013年12月的一份报告中得出结论，仅利用现有的常识很难采取有效措施，委员会要求从国内外专家那里进一步收集以下六个主题的技术信息：(1)污水储存；(2)污水处理；(3)从海港海水中清除放射性物质；(4)建筑物内受污染水的控制；(5)限制地下水流入现场的场地管理；以及(6)了解地下水流动，包括放射性核素的行为。在这项工作中，将努力解决专题3、4和5的各个方面。福岛第一核电站最具问题的放射性核素是锶-90、铯-134和铯-137，因为它们形成高度可溶的盐类，其环境行为分别类似于常见的(过量)地下水离子钙离子和钾离子，因此它们是可流动的、可生物利用的和直接令人关切的。FDNPP的初步工作侧重于工厂和储存容器中Cs的去除，该项目旨在还包括锶-90和Co-60的清理。这项英国和日本(伯明翰大学、日本原子能机构、九州大学、柴浦理工学院工程学院)的联合提案将建立在建立在开发、表征和测试三种用于固定放射性核素的新系统的国际领先合作工作的基础上。第一组材料的新奇之处在于，它们被设计为可通过磁分离来移除，而不是传统的重力进料固定床柱系统，后者需要将污水泵入系统。这为现场使用提供了工程灵活性和使用范围；例如，它们可以放置在受污染的水中，然后与附加的放射性核素一起磁力收集。第二组材料的新奇之处在于，它们是由嗜盐生物制造的，即那些生活在海水等高盐浓度环境中的生物，因此可以生产并用于净化福岛核电站附近的海港海水或咸水地下水。最后一套材料的新颖性和重要性在于这样一种设计，即它们可以被浇注或注入地下，形成多孔屏障，从而捕获目标放射性核素，防止它们进一步迁移。所有三套材料都将使用先进的仪器进行表征，以便充分了解放射性核素的捕获机制和并入的稳定性。这些材料不仅将帮助福岛第一核电站的清理工作，还将用于减少未来的任何事故，并可能在英国退役活动和遗留废物清理中发挥作用。在这个项目中，目标是评估三套材料的范围，以提供关键数据和平台，与日本化学和土木工程师公司共同支持进一步的开发和工艺实施。

Despite tremendous technological and financial effort in Japan to deal with the effects of the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident many challenges remain. The Government of Japan's Committee on Countermeasures for Contaminated Water Treatment considered existing and proposed measures and technologies "to remove" contaminated water, "to keep out" the inflow of water into the sources of contamination and to "prevent leakage" of contaminated water into the environment. They concluded in a December 2013 report that it was difficult to take effective measures using only existing general knowledge and the committee asked for technical information to be further gathered from both domestic and overseas experts in the following six topics: (1) Storage of contaminated water, (2) Treatment of contaminated water, (3) Removal of radioactive materials from the seawater in the harbour, (4) Control of contaminated water within buildings, (5) Site management to restrict groundwater flowing into the site, and (6) Understanding groundwater flow including the behaviour of radionuclides. In this work efforts will be made to tackle aspects of topics 3, 4 and 5. The most problematic radionuclides at the FDNPP are Sr-90, Cs-134 & Cs-137 because they form highly soluble salts and have environmental behaviour similar to the common (excess) groundwater ions Ca2+ and K+, respectively, hence they are mobile, bioavailable and of immediate concern. Initial work at the FDNPP focused on removal of Cs at the plant and in storage vessels, this project aims to also cover the clean-up of Sr-90 and Co-60.This joint UK/Japan (University of Birmingham, Japanese Atomic Energy Agency, Kyushu University, College of Engineering at Shibaura Institute of Technology) proposal will build on the work of an established internationally leading collaboration for the development, characterisation and testing of three novel systems for immobilisation of radionuclides. The novelty of the first set of materials is that they are designed to be removable by magnetic separation rather than traditional gravity fed fixed bed column system where effluent needs to be pumped into the system. This gives engineering flexibility and scope for use in the field; for example they could be positioned deposited in contaminated water and then magnetically collected along with attached radionuclides. The novelty of the second set of materials are that they are being designed to be made by halophilic organisms, i.e. those that live in high salt concentration environments such as seawater, and could therefore be produced and used in decontamination of harbour seawater or saline groundwater near the FDNPP. The novelty and importance of the final set of materials is a design so that they can be poured or injected into the ground to form porous barriers that will trap the targeted radionuclides and prevent their further migration. All three sets of materials will be characterised using advanced instrumentation so that the mechanism of radionuclide entrapment and the stability of incorporation is fully understood.These materials will not only assist in the clean-up at the FDNPP but will also be available for the abatement of any future accidents and may have a role to play in UK decommissioning activities and legacy waste clean-up. Within this project the goal is to evaluate the scope of the three sets of materials to provide key data and a platform to underpin further development and process implementation in conjunction with Japanese Chemical and Civil Engineers.