微波烧结钆锆烧绿石固化多核素的机理与辐照效应研究

Studies about pyrochlore Gd2Zr2O7 is one of the most hot and difficult problem in nuclear waste disposal,since it shows considerable potential for immobilizing radionuclide including long half-life actinides (eg.239Pu and 237Np) or minor actinides.In this project,a new and rapid synthesis method of pyrochlore Gd2Zr2O7 structured synroc-solidified matrix by microwave sintering technology is put forward.The basic research about the artificial-mineral analoged solidification in dealing with the high-level radioactive waste from TRPO treatment process would be studied.Furthermore,the comprehensive performances of solidified matrix in simulated geological repository environment are to be evaluated with α,β and γ-ray acceleration irradiation technology.The isomorphism effect of analoged multi-nuclides in microwave sintering process,the occurrence status (like priority placeholder,oxidation valence,charge compensation etc.) in solidified matrix,the immobilization mechanism for radionuclide,the physical structure and chemical stability of synroc-solidified matrix are within the researching scope of this project.More importantly,the diffusion,migration and aggregation behavior of radionuclide as the synroc-solidified crystal shedding,the radiation caused damage mechanisms,and the evaluation methods for long-term security and stability of the pyrochlore structured artificial-mineral solidified matrix would be focused in this project. The achievements of the research project will lay the scientific foundation and provide powerful technical support for the engineering applications of pyrochlore structured mineral in disposing multi-radionuclide included high-level radioactive waste.

钆锆烧绿石（Gd2Zr2O7）被认为是人造岩石（矿物）固化239Pu和237Np等超长半衰期锕系或次锕系核素的理想基材，是目前核废物处理处置等领域研究的热点和难点之一。本项目尝试采用微波烧结技术探索钆锆烧绿石结构人工矿物固化体的快速合成新方法，开展基于我国自主研发核废物TRPO处理流程产生高放废物的人造矿物模拟固化基础研究；在模拟地质处置库环境下，借助α、β和γ射线加速辐照等技术，进行人工矿物固化体综合性能评价。研究在微波烧结过程中，多模拟核素的类质同象作用及其在固化体中赋存状态（优先占位、氧化价态、电荷补偿等）与固核机理以及人工矿物固化体的结构与化学稳定性；重点考虑人工矿物固化体蜕晶质化过程中核素扩散、迁移和聚集等行为，阐明其辐照损伤机制，建立烧绿石结构人工矿物固化体长期安全稳定性评价方法。 项目研究的成果，将为烧绿石结构矿物多核素高放废物处理的工程化应用提供重要的科学依据和技术支撑。

钆锆烧绿石被认为是人造岩石（矿物）固化锕系或次锕系核素的理想基材之一，是目前高放废物处理处置领域研究的热点和难点之一。本项目探索性利用微波技术开展了钆锆烧绿石基核素固化体的快速烧结新方法，开展了基于我国自主研发核废物TRPO处理流程尾端产生两种典型高放废物的模拟固化基础研究；在模拟地质处置库环境下，借助射线加速辐照等技术，对人工矿物固化体的综合性能进行了评价。研究了微波烧结过程中，多模拟核素的类质同象作用及其在固化体中赋存状态、固核机理以及固化体的结构与化学稳定性；重点考查了固化体蜕晶质化过程中核素的扩散、迁移和聚集等行为，阐明了其辐照损伤机制。同时，对典型拥有混合价态的核素氧化物—U3O8的钆锆烧绿石固化机理及稳定性等也进行了研究。项目的研究成果，将为烧绿石固化复杂高放废物的工程化应用提供重要的科学数据和技术支撑。.在基金的支持下，本项目发表论文15篇（其中SCI收录论文15篇），申报国家发明专利3项，出版专著1部。培养博士后1名，本科生、硕士研究生9名。