Abstract Source term analysis not only can provide the fundamental data for radiation shielding design, but also has a guiding significance for in-service inspection of the reactor. A numerical analysis model (MAST1.0) for activated products in the secondary loop system of the molten salt reactor (MSR) was developed. The deviation of the simulation results between MAST1.0 and ORIGEN-S are less than 7%, which indicates that they are in good agreements. The amounts of the activated products (16N, 20F and 19O) and the corrosion activated products (60Co, 55Fe, 54Mn, 51Cr, 59Ni, etc.) in the second loop were also obtained by MAST1.0, which show that the total activity of 16N, 20F and 19O is two orders of magnitude higher than that of the corrosion activated products in normal operating conditions. Flow rate has a significant effect on the distribution of 16N, 20F and 19O in the secondary loop. The total activity of 16N, 20F and 19O outside of the core increases monotonically with the increase of the flow rate. The concentration of 16N, 20F and 19O outside of the core tends to be stable, when the flow rate is greater than 1 × 106 cm3 s−1. Corrosion activated products show slowly increasing and decreasing trends in reactor startup and shutdown conditions, so they are the key radioactive sources for radiation protection after long-term shutdown of the reactor.

中文翻译：

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一体化熔盐堆二回路活化产物源项动态特性研究

摘要 源项分析不仅可以为辐射屏蔽设计提供基础数据，而且对反应堆在役检查具有指导意义。开发了熔盐反应堆 (MSR) 二次回路系统中活化产物的数值分析模型 (MAST1.0)。MAST1.0与ORIGEN-S的仿真结果偏差小于7%，表明两者吻合良好。通过 MAST1.0 还得到了第二个循环中活化产物（16N、20F 和 19O）和腐蚀活化产物（60Co、55Fe、54Mn、51Cr、59Ni 等）的量，表明总活性16N、20F 和 19O 比正常操作条件下腐蚀活化产品高两个数量级。流量对二次回路中 16N、20F 和 19O 的分布有显着影响。核外 16N、20F 和 19O 的总活度随着流速的增加而单调增加。当流速大于 1 × 106 cm3 s−1 时，核外 16N、20F 和 19O 的浓度趋于稳定。腐蚀活化产物在反应堆启动和停堆条件下呈现缓慢增减趋势，是反应堆长期停堆后辐射防护的关键放射源。当流速大于 1 × 106 cm3 s−1 时。腐蚀活化产物在反应堆启动和停堆条件下呈现缓慢增减趋势，是反应堆长期停堆后辐射防护的关键放射源。当流速大于 1 × 106 cm3 s−1 时。腐蚀活化产物在反应堆启动和停堆条件下呈现缓慢增减趋势，是反应堆长期停堆后辐射防护的关键放射源。