小型模块化熔盐堆控制棒布置的物理分析

sm-TMSR是中国科学院钍基熔盐堆核能系统中心（TMSR）设计的一款小型模块化多用途钍基熔盐示范堆。本文就sm-TMSR堆芯的控制棒布置进行了物理分析。首先，对熔盐堆特有的反应性变化现象进行了分析，提出了sm-TMSR控制棒的功能和需求，即:对于调节棒，要求设计的总价值在寿期初等于或略大于2.5×10-2，寿期末等于或略大于2.06×10-2；对于停堆棒，考虑卡棒准则，要求设计的单根棒价值在寿期初大于等于2.1×10-2；其次，计算了不同位置、不同控制棒孔道直径以及有无哈氏合金套管的单根控制棒价值；最后根据控制棒价值的需求大小，确定了控制棒组件在堆芯较为优化的物理设计:①控制棒组件孔道直径为9?cm，无哈氏合金套管；②4根控制棒成“十”字形分布，2根停堆棒均匀布置在堆芯的第1圈，2根调节棒均匀布置在堆芯的第6圈位置。 

Physical Analysis of Control Rods Arrangement in Core of?a Small Modular Molten Salt Reactor

sm-TMSR is a small modular multi-purpose thorium-based molten salt demonstration reactor designed by Center for Thorium Molten Salt Reactor System?(TMSR), CAS. In this paper,?the physical analysis of the control rod arrangement was carried out.?Firstly, we analyzed the unique reactivity variation in the molten salt reactor and proposed?the function and requirements of the control rods. Namely, for regulating rods, the total design value is required to be equal to or slightly greater than 2.5×10-2?at the beginning of life and 2.06×10-2?at the end of life, respectively. For shut-down rods, "one stuck rod" criterion is considered,?and the design value of a single rod is required to be more than 2.1×10?-2?at the beginning of life. Secondly, we calculated?the?value of the?single control rod?at different locations in the core, for different size of the channel?and the channel with or without?a Hastelloy sleeve.?Finally, according to the requirements of control?rods, the optimized physical design of the control rod assembly in the core is determined, i.e,?a.?Diameter of channels in control rod assemblies are 9 cm, and it?is without Hastelloy sleeve; b.?Four control rods are distributed in the shape of "十", two shut-down rods are uniformly arranged in the first circle and two?regulating rods are uniformly arranged in the sixth circle of the core.