Because a pool scrubbing is important for reducing radioactive aerosols to the environment for a nuclear reactor in a severe accident situation, many researches have been performed. However, decontamination factor (DF) dependence on aerosol concentration was seldom considered in an aerosol number concentration with limited aerosol coagulation. To investigate an existence of DF dependence on the concentration, DF in a pool scrubbing with 2.4 m water submergence was derived from aerosol measurements by light scattering aerosol spectrometers. It was observed that DF increased monotonically with decreasing particle number concentration in a constant thermohydraulic condition: a gradual increase from 10 to 32 in the range of 1.3×10¹¹ - 8.0×10¹¹/m³ at the inlet and a significant increase from 32 to 77 in the range of 3.6×10¹⁰ - 1.3×10¹¹/m³. Two validation experiments were conducted in the range with the gradual DF increase to confirm whether the DF dependence is a real pool scrubbing phenomenon. In addition, characteristics of the DF dependence in different water submergences were investigated experimentally. It was found that the DF dependence became more significant in higher water submergence. Significant DF dependence was observed in the condition of the water submergence higher than 1.6 m and the inlet particle number concentration less than around 1×10¹¹ /m³. It is recommended to perform further analysis for the DF dependence mainly in such condition since it could make a difference to both experiment and model of the pool scrubbing.

中文翻译：

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净化池中去污因子对气溶胶浓度的影响的实验研究

因为池洗涤对于在严重事故情况下减少对核反应堆的环境中的放射性气溶胶很重要，所以已经进行了许多研究。然而，在气溶胶凝结受限的气溶胶数量浓度中，很少考虑去污因子（DF）对气溶胶浓度的依赖性。为了研究DF对浓度的依赖性，从光散射气溶胶光谱仪的气溶胶测量值中得出了水浸入2.4 m的水池洗涤池中的DF。据观察，与DF在恒定热液压条件减少颗粒数浓度单调增加：从10逐渐增加至32中的1.3×10的范围¹¹ - 8.0×10 ¹¹ /米³在进口和从32到77中的3.6×10的范围内的增加显著¹⁰ - 1.3×10 ¹¹ /米³。在DF逐渐增加的范围内进行了两次验证实验，以确认DF依赖性是否为真实的池清理现象。此外，实验研究了不同水淹没条件下DF的依赖性。发现在较高的水淹没条件下，DF依赖性变得更加重要。在水淹没高于1.6 m且入口颗粒数浓度小于1×10 ¹¹ / m ³的情况下，观察到了显着的DF依赖性。。建议主要在这种情况下对DF依赖性进行进一步分析，因为这可能会影响池洗涤的实验和模型。