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，但仍存在许多挑战。日本政府的污染水处理对策委员会审议了现有的和拟议的措施和技术，以“去除”受污染的水，“阻止”流入污染源的水，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，仅利用现有的一般知识很难采取有效措施，委员会要求进一步从国内外专家那里收集以下六个主题的技术信息：(1)污染水的储存，(2)污染水的处理，(3)从港口海水中清除放射性物质，(4)控制建筑物内的污染水，(5)场地管理以限制地下水流入场地，(6)了解地下水流动，包括放射性核素的行为。在这项工作中，将努力处理主题3、4和5的各个方面。FDNPP中问题最大的放射性核素是Sr-90， Cs-134和Cs-137，因为它们形成高可溶性盐，其环境行为分别类似于常见（过量）地下水离子Ca2+和K+，因此它们是可移动的，生物可利用的，并且是直接关注的。FDNPP最初的工作重点是去除工厂和储存容器中的Cs，该项目旨在还包括Sr-90和Co-60的清理。这项联合英国/日本（伯明翰大学、日本原子能机构、九州大学、柴浦工业大学工程学院）的提案将建立在一个已建立的国际领先合作的基础上，该合作旨在开发、表征和测试三种新型放射性核素固定化系统。第一组材料的新颖之处在于，它们被设计成可以通过磁分离去除，而不是传统的重力馈送固定床柱系统，在这种系统中，污水需要泵入系统。这为工程提供了灵活性和在现场使用的范围；例如，它们可以被放置在受污染的水中，然后与附着的放射性核素一起被磁性收集。第二套材料的新颖之处在于，它们是由嗜盐生物（即生活在高盐浓度环境（如海水）中的生物）制造的，因此可以生产和用于净化海港海水或FDNPP附近的含盐地下水。最后一组材料的新颖和重要之处在于，它们可以被倾倒或注入地下，形成多孔屏障，以捕获目标放射性核素并防止其进一步迁移。所有三组材料将使用先进的仪器进行表征，以便充分了解放射性核素捕获的机制和掺入的稳定性。这些材料不仅有助于FDNPP的清理工作，还可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，提供关键数据和平台，以支持与日本化学和土木工程师合作的进一步开发和过程实施。

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.