The single-fluid double-zone thorium molten salt reactor (SD-TMSR) allows for online reprocessing fission products and adding nuclear fuel, which provides a high Th-U breeding capability for thorium utilization. Although ¹³⁵Xe in the core can be online extracted by the helium bubbling system during reactor operation to improve the reactor neutron economy, it would decay to the long-lived ¹³⁵Cs with a half-life of 2.3 × 10⁶ years, which is undesired from the viewpoint of the development of nuclear energy. The total production of ¹³⁵Cs decayed from the extracted ¹³⁵Xe is about 1.83 tons for the SD-TMSR after 60 years operation. To reduce the significant accumulation of ¹³⁵Cs, we propose a cooling transmutation method, by which the produced ¹³⁵Cs is reinjected into the core for transmutation. First, a separation and multigroup cooling system in the SD-TMSR is adopted to enhance the mass fraction of decayed ¹³⁵Cs in the total Cs isotopes from 29% to 75%. Then, the separated Cs isotopes with optimized mass fraction of ¹³⁵Cs are online injected into the core for transmutation. The total transmuted mass of ¹³⁵Cs is about 0.61 tons after 60 years operation, corresponding to the transmuted fraction of about 37.42% and the transmutation rate of 10.17 kg/(GWe y). Moreover, the net ²³³U production is about 2.03 tons which is much larger than the initial ²³³U loading inventory of the SD-TMSR, indicating that the Th-U breeding mode for the transmutation of ¹³⁵Cs in the SD-TMSR can be achieved over 60 years.

中文翻译：

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单流体双区钍熔盐反应堆中135Cs的嬗变

单流体双区钍熔盐反应堆（SD-TMSR）允许在线后处理裂变产物和添加核燃料，为钍利用提供高Th-U育种能力。尽管堆芯中的¹³⁵ Xe 可以在反应堆运行期间通过氦气鼓泡系统在线提取以提高反应堆中子经济性，但它会衰变成长寿命的¹³⁵ Cs，半衰期为 2.3 × 10 ⁶ 年，这是不希望的从发展核能的角度来看。SD-TMSR 在运行 60 年后，从提取的¹³⁵ Xe 中衰变的¹³⁵ Cs 的总产量约为 1.83 吨。减少¹³⁵的显着积累Cs，我们提出了一种冷却嬗变方法，通过该方法将产生的¹³⁵ Cs 重新注入核心进行嬗变。首先，在SD-TMSR分离和多组冷却系统采用，以提高衰减的质量分数^135个Cs的在总铯同位素从29％至75％。然后，将分离出的具有¹³⁵ Cs优化质量分数的 Cs 同位素在线注入到岩心中进行嬗变。运行60年后，¹³⁵ Cs的总嬗变质量约为0.61吨，对应的嬗变率约为37.42%，嬗变率为10.17 kg/(GWe y)。此外，净²³³ U 产量约为 2.03 吨，远大于最初的²³³SD-TMSR 的 U 加载清单，表明 SD-TMSR 中¹³⁵ Cs嬗变的 Th-U 育种模式可以实现 60 多年。