重水冷却钍基长寿命模块化小堆概念设计研究

基于传统压水堆（PWR）技术，提出一种重水冷却的钍基长寿命模块化小堆（RMSMR）的概念设计方案，采用二维模型系统分析并对比了PWR和RMSMR的燃料类型、慢化剂类型等参数，获得反应堆各项中子学参数的变化机理；然后基于二维计算结果提出了最终的三维堆芯设计方案，并开展了初步的中子物理和热工安全分析。研究表明，RMSMR在设计上采用三区燃料布置来展平功率，采用钍-铀燃料维持了负空泡系数，通过布置增殖包层提高了堆芯的转换比（CR）；RMSMR采用了重水冷却剂可以使中子能谱硬化，从而提高CR，减小寿期反应性波动，增加堆芯寿期；RMSMR能够在100 MW电功率下维持6 a的安全运行。本文研究可为新型反应堆的设计发展提供借鉴。 

Conceptual Design of a Reduced Moderation Long-Life Heavy Water Cooled Thorium Small Modular Reactor

This paper proposes a conceptual design for an innovative reactor, reduced moderation small modular reactor(RMSMR), based on the technology of conventional PWRs. In this paper we firstly establish a two-dimensional model to analyze the influences of fuel types, coolant types and other parameters of PWR and RMSMR. Then a three-dimensional design scheme is proposed and a preliminary neutronic and thermal-hydraulic analysis is carried out. The results show that the power distribution can be flattened by adopting a three-zone 232 Th-233 U dioxide fuel configuration, a negative void coefficient can be ensured by using uranium-thorium dioxide fuel, and the conversion effect can be enhanced by utilizing blanket regions. RMSMR utilizes the small scattering cross section of heavy water to yield an epithermal-to-fast neutron spectrum, which is also beneficial for attaining a large conversion ratio, a long core lifetime and reducing the burnup reactivity swing. It is concluded that RMSMR can sustain the power generation of 100 MWe for 6 years without refueling, which is of referential value to the design of new generation reactors.