小型自然循环钠冷堆堆芯初步设计研究

Preliminary Design Research on Core of Small Natural-circulation Sodium-cooled Reactor

提出了一种适用于分布式发电系统的小型自然循环钠冷堆-AMTEC系统。通过对堆芯的临界计算和热工水力分析,研究了堆芯燃料装载量不变情况下,芯块半径、燃料棒长度和圈数对堆芯有效增殖因数keff、堆芯压降和传热的影响。同时分析了不同额外停堆裕量下,B4C吸收层厚度和堆芯初始剩余反应性随燃料棒圈数的变化关系。计算结果表明:保持堆芯当量直径和冷却剂通道总截面积不变的情况下,减少燃料棒圈数和活性区长度不仅可增加keff,且能降低堆芯压降;为提高额外停堆裕量需增加吸收层厚度,但降低了堆芯初始剩余反应性,不利于电厂的经济性。

A small natural-circulation sodium-cooled reactor-AM TEC system was pres-ented as a distributed generation system . According to the criticality calculation and thermal-hydraulic analysis of the core when the total fuel mass was constant ,the influ-ence of pellet radius ,fuel pin length and the number of rings of fuel pins upon the effec-tive multiplication factor kef , pressure drop across the core and heat transfer was analyzed .Additionally ,the B4 C absorber thickness and beginning-of-life excess reactivi-ty under different numbers of rings of the fuel pins were studied when the assumed addi-tional shutdown margin was different .The results show that decreasing the number of rings and active fuel length would increase kef and decrease pressure drop across the core w hen the core equivalent diameter and total cross-sectional area of the coolant channel are unchanged .In order to increase additional shutdow n margin ,the absorber thickness should be increased while the beginning-of-life excess reactivity and power plant econo-my would decrease .