Nuclear Energy Systems with Zero Release of Radioactive Materials

建立未来核能与地球环境、与人类社会和谐发展的途径是核能研究与开发的最终目标。除了裂变技术外，还以聚变和加速器技术为基础，对核能系统的可行性进行了全面研究，以同时满足至少以下四个目标；(1)能源生产；(2)燃料育种；(3)放射性物质嬗变；(4)系统安全。系统的中子丰度是实现这些目标的关键因素。过剩中子产生中的裂变反应潜力较差，无法高效转化核废料。为了克服这些困难，引入了散裂反应和聚变反应等非裂变产生中子的反应来改善中子平衡。提出了评价各种外部中子源的多余中子生成和能量平衡的一般方法。根据所提出的方法，对不同核能系统中核废料的余中子、能量平衡和嬗变进行了对比分析。为评价裂变产物的嬗变，建立了核数据库。研究了化学/同位素分离方法和系统的安全特性。最后得出结论，采用加速器驱动堆和裂变-聚变混合堆的多组分系统在核能系统接近放射性物质零释放方面具有明显优势。

An ultimate goal of the nuclear energy research and development is to establish the way to harmonize the nuclear energy with global environment and human society in future. The comprehensive study has been performed based on the fusion and accelerator technologies in addition to the fission technology for the feasibility of the nuclear energy system that satisfies simultaneously at least the following four objectives ; (1) energy production, (2) fuel breeding, (3) Transmutation of radioactive materials, (4) system safety.Neutron abundance of the system is the key element to achieve these objectives. The potential of fission reaction in excess neutron generation is rather poor to transmute nuclear waste with high efficiency. To overcome these difficulties, non-fission neutron producing reactions such as spallation and fusion reactions are introduced to improve neutron balance. The general methodology was developed to evaluate the excess neutron generation and energy balance in the various external neutron sources.Comparative analyses on the excess neutron, energy balance and transmutation of the wastes in various nuclear energy system have been performed based on the proposed methodology. Nuclear database were prepared for the evaluating the transmutation of fission productions. Chemical/isotope separation methods and the safety characteristics of the system were also studied.Finally, it is concluded that multi-component system with Accelerator-driven reactor and Fission-fusion hybrid reactor demonstrates clear advantage in approaching Zero-Release of Radioactive Materials from the nuclear energy system.