放电等离子烧结钆锆烧绿石的晶格固核机理与稳定性研究

Abstract: Studies about Gd2Zr2O7 pyrochlore 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, spark plasma sintering (SPS), is put forward to synthesis Gd2Zr2O7 pyrochlore structured synroc-solidified matrix. 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, γ and heavy-ion acceleration irradiation technology and so on. More importantly, The isomorphism effect of analoged multi-nuclides in spark plasma 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. The pyrochlore immobilizing mechanism for radionuclide in crystal lattice would be revealed. The evaluation methods for long-term security and stability of the pyrochlore structured artificial-mineral solidified matrix would be focused in this project..The result of this project will provide scientific foundation and powerful technical support for the evaluation of long-term security and stability of waste forms and the engineering applications of pyrochlore structured minerals in disposing multi-radionuclide waste.

钆锆烧绿石（Gd2Zr2O7）被认为是人造矿物（陶瓷）晶格固化239Pu和237Np等拥有超长半衰期锕系或次锕系核素的理想基材之一，是目前核废物处理处置等领域研究的热点和难点。本项目尝试利用放电等离子烧结技术探索钆锆烧绿石结构矿物固化体的高效合成新方法；开展基于我国自主研发核废物TRPO处理流程尾端高放废物的矿物晶格固化基础研究；在模拟地质处置库环境下，借助射线（α、β、γ和重离子）加速辐照等技术，对人工矿物固化体的综合性能进行评价。重点研究在放电等离子烧结过程中，多种核素共存于固化体时的类质同象作用及其在固化体中的赋存状态（优先占位、氧化价态、电荷补偿等）以及固化体的性能响应机制；阐明钆锆烧绿石对多核素的晶格固化机理，建立烧绿石结构矿物固化体的长期安全稳定性评价方法。 .项目的研究成果，将为烧绿石结构矿物固化成分复杂高放废物的安全稳定性评价及工程化应用提供重要的科学依据和技术支撑。

钆锆烧绿石（Gd2Zr2O7）被认为是人造矿物（陶瓷）晶格固化239Pu和237Np等拥有超长半衰期锕系或次锕系核素的理想基材之一，是目前核废物处理领域研究的热点和难点之一。本项目探索性利用放电等离子烧结技术开展了钆锆烧绿石结构矿物固化体的高效合成新方法；开展了基于我国自主研发核废物TRPO处理流程尾端高放废物的矿物晶格固化基础研究；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。重点研究了放电等离子烧结过程中，多种核素共存于固化体时的类质同象作用及其在固化体中的赋存状态以及固化体的性能响应机制；阐明了钆锆烧绿石对多核素的晶格固化机理。项目的研究成果，将为烧绿石结构矿物固化成分复杂高放废物的安全稳定性评价及工程化应用提供重要的科学依据和技术支撑。.在基金的支持下，本项目发表SCI收录论文13篇，申报国家发明专利1项，整理待出版专著1部。培养本科生、硕士研究生9名。