The diffusion length of 222Rn in uraniferous waste rock was determined through a novel experiment. Large PVC columns were filled to different depths in the range from 0.5 m to 3.0 m with waste rock material from the Ranger uranium mine and the build-up of 222Rn activity concentration in the column headspace above the material was measured after closing the columns with a lid. Measurements were made approximately one month after filling the columns and again after approximately one and two years. The average 222Rn diffusion length derived from the measurements was 1.9 ± 0.2 m in the dry material. The corresponding diffusion coefficient was (7.3 ± 0.7) × 10-6 m2 s-1. For an infinitely thick layer of the dry material, the average value of the 222Rn exhalation flux density relative to the 226Ra activity concentration was estimated as (5.3 ± 0.3) × 10-4 Bq m-2 s-1 per Bq kg-1. From the diffusion length, the waste rock material was characterised as both a source and attenuator of 222Rn for its proposed use as the surface cover on the final landform of the remediated Ranger uranium mine.

中文翻译：

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Radon-222铀长石的扩散长度和呼出特性及其在澳大利亚干湿热带的矿山修复中的应用。

通过一个新颖的实验确定了222Rn在含铀废石中的扩散长度。用Ranger铀矿的废岩石材料将大型PVC色谱柱填充到0.5 m至3.0 m的不同深度，并在用高压釜关闭色谱柱后测量该材料上方色谱柱顶部空间中222Rn活性浓度的增加。盖。在填充色谱柱后大约一个月进行一次测量，大约一年和两年后再次进行测量。由测量得出的平均222Rn扩散长度在干燥材料中为1.9±0.2 m。相应的扩散系数为（7.3±0.7）×10-6 m2 s-1。对于无限厚的干燥材料层，相对于226Ra活性浓度的222Rn呼气通量密度的平均值估计为（5.3±0。3）每Bq kg-1×10-4 Bq m-2 s-1。从扩散长度来看，废石料既可作为222Rn的来源，又可作为衰减剂，拟议用作修复的Ranger铀矿最终地貌的表层。