Abstract The molten chloride salt fast reactor (MCFR) with Th-U fuel cycle is attracting more and more attention because of its excellent performance, such as high solubility of actinides, superior breeding capacity, low waste production, and high inherent safety. First of all, the breeding capability of an MCFR at equilibrium state was optimized by an in-house automated optimization program. Based on an optimized MCFR, an investigation of Th-U cycle performance was performed. Due to the lack of available 233U in nature, transuranium (TRU), low-enriched uranium (LEU), and Pu were employed as the startup fissile materials, and two different transition scenarios, a breeding and burning (B&B) scenario and a pre-breeding and burning (PBB) scenario were studied. The results show that the breeding performance in an MCFR is attractive and that the Th-U fuel transition can be achieved smoothly by using LEU, Pu, or TRU as startup fissile materials. In the B&B scenario, the average net 233U production rate in the LEU-started, TRU-started, and Pu-started modes during 200-year operation is 374, 321, and 323 kg/a, respectively, at the reprocessing rate of 200 L/day. While in the PB&B scenario the average annual 233U production is about 570 kg for all startup cases at a reprocessing rate of 40 L/day, and the corresponding doubling time is about 9.6 years. Besides, the values of the fuel Doppler coefficient and density coefficient are negative, and the total temperature coefficient of reactivity in all scenarios is below −8 pcm/K. In addition, the value of radiotoxicity of the Th-U cycle in an MCFR is lower than that in other molten salt reactors like the molten-salt breeder reactor and the molten fluoride salt reactor due to the lower buildup of fission products and TRU under its hard spectrum.

中文翻译：

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优化的氯化熔盐快速反应器中的 Th-U 育种性能

摘要 Th-U燃料循环氯化熔盐快堆(MCFR)以其锕系元素溶解度高、增殖能力强、废物产生量低、固有安全性高等优异性能越来越受到人们的关注。首先，平衡状态下 MCFR 的育种能力通过内部自动化优化程序进行了优化。基于优化的 MCFR，对 Th-U 循环性能进行了调查。由于自然界中缺乏可用的 233U，超铀 (TRU)、低浓缩铀 (LEU) 和 Pu 被用作启动裂变材料，以及两种不同的过渡方案，繁殖和燃烧 (B&B) 方案和预- 研究了繁殖和燃烧 (PBB) 方案。结果表明，MCFR 的育种性能具有吸引力，并且通过使用 LEU、Pu 或 TRU 作为启动裂变材料可以顺利实现 Th-U 燃料转换。在 B&B 情景中，200 年运行期间 LEU 启动、TRU 启动和 Pu 启动模式的平均净 233U 生产率分别为 374、321 和 323 kg/a，后处理率为 200升/天。而在 PB&B 方案中，所有启动案例的年均 233U 产量约为 570 公斤，后处理率为 40 升/天，相应的倍增时间约为 9.6 年。此外，燃料多普勒系数和密度系数均为负值，所有情景下反应性总温度系数均低于-8 pcm/K。此外，