高放废物地质处置中核素迁移研究进展

Research Progress of Nuclide Migration in Geological Disposal of High-level Radioactive Wastes

  • 摘要: 核技术在工业、农业、医学等领域有广泛应用,但也产生了大量放射性废物,其中高放废物含有大量放射性强、毒性大、半衰期长和释热量大的核素,对自然环境和人类健康构成了巨大的威胁,其安全处置一直是放射性废物管理中的重点难点问题,受到国际社会的广泛关注。目前,深地质处置被认为是高放废物处理处置最有效可行的方法,而地质屏障中放射性核素迁移研究是高放废物地质处置安全评价的关键课题之一。本文首先对高放废物地质处置及核素迁移研究进行概述,然后论述了核素迁移数值模拟研究的关键技术(包括物理模型以及数学模型),最后分析了数值模拟在不同核素迁移研究中的应用进展。通过综合分析可知,目前核素迁移研究还存在以下主要问题:1) 核素迁移的机理和规律尚不完全清楚,需要更多的基础研究和数据支撑;2) 核素迁移的实验技术和设备还有待改进,需要更高的精度和灵敏度;3) 核素迁移的数值模拟还存在不确定性和误差,需要进行更有效的验证和优化。未来的研究方向主要包括:1) 加强核素迁移的理论研究,揭示核素在复杂条件下的迁移行为及其控制机制;2) 发展核素迁移的实验技术,提高实验数据的质量和可信度;3) 创新核素迁移的数值模拟方法,增强模型的适应性和预测能力;4) 完善核素迁移的安全评价体系,建立更合理的评价指标和方法。

     

    Abstract: With the rapid development of nuclear energy, the nuclear technology has been widely used in various fields, such as industry, agriculture and medicine. However, the development of the nuclear industry also produces a large amount of radioactive waste, especially high-level radioactive waste (HLW), which has a quantity of nuclides with high radioactivity, high toxicity, long half-life and high heat generation. How to realize the long-term safe isolation of HLW from the environment is an important issue in global environmental protection. If it is not safely disposed, it will cause serious damage to the natural environment and human society. Therefore, the safe disposal of HLW is a key and difficult issue in nuclear waste management, and has been widely concerned by the international community. The deep geological disposal is generally considered to be the most effective and feasible method for disposing HLW. The main idea of deep geological disposal is to establish a geological disposal repository of HLW at a depth of 500-1 000 m underground where the processed HLWs are buried, and isolate HLWs from the biosphere through a multiple barrier system. The study of radioactive nuclide migration in geological barriers is one of the key topics for safety evaluation of deep geological disposal of HLW. In this paper, firstly the geological disposal of HLW and the study of radioactive nuclide migration were summarized, and then the key technologies of numerical simulation (the physical and mathematical models) for radioactive nuclide migration were discussed. Finally, the application progress of numerical simulation for migration of different radionuclides was analyzed. At present, there are the following main issues to be addressed in the study of radioactive nuclear migration: 1) The mechanism and law of nuclear migration are not completely clear, requiring more basic research and data support; 2) The experimental technology and equipment of nuclear migration need to be improved, requiring higher accuracy and sensitivity; 3) The numerical simulation of nuclear migration still has uncertainty and error, which needs more effective verification and optimization. The future research directions mainly include: 1) strengthening the theoretical study of nuclide migration and revealing the migration behavior and its control mechanism under complex conditions; 2) developing the experimental technology of nuclide migration and improving the quality and credibility of experimental data; 3) innovating the numerical simulation method of nuclide migration and enhancing the adaptability and prediction ability of the model; 4) improving the safety evaluation system of nuclide migration and establishing more reasonable evaluation indicators and methods.

     

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