210Po, a highly toxic element with strong volatility, is one of the main source term of Gen-IV Lead-cooled Fast Reactor (LFR). Therefore, the radiological safety issue caused by 210Po has become an important issue in LFR related research. In order to simulate the behavior of 210Po in LFR, this work developed a multi-physics model of LFR from the perspective of radioactive transport. Considering the effects of nuclides decays, cover gas leakages, containment ventilation and Po aerosol deposition, a comprehensive simulation was carried out to evaluate these effects on the 210Po concentration in detail. Preliminary results indicate that during normal operation, most of the 210Po in the LBE exists in the form of PbPo, and about 10-9 210Po could evaporate from the LBE into the cover gas, and then further leak into the containment. In addition, even if the leakage rate of 210Po in the cover gas into the containment is maintained at 5‰ per day, due to the deposition of 210Po itself, the 210Po contamination on the inner surface of the containment is still below the radioactivity concentration limits.

中文翻译：

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铅冷快堆中钋输运行为的多物理场模型开发

210Po是一种剧毒、挥发性强的元素，是第四代铅冷快堆（LFR）的主要来源项之一。因此，210Po引起的放射安全问题成为LFR相关研究的重要课题。为了模拟210Po在LFR中的行为，本工作从放射性输运的角度开发了LFR的多物理场模型。考虑到核素衰变、覆盖气体泄漏、安全壳通风和 Po 气溶胶沉积的影响，进行了综合模拟以详细评估这些对 210Po 浓度的影响。初步结果表明，在正常运行过程中，LBE 中大部分 210Po 以 PbPo 的形式存在，约 10-9 210Po 可从 LBE 蒸发到覆盖气体中，然后进一步泄漏到安全壳中。此外，