【摘要】 铀矿地质勘探设施退役后,其放射性核素已通过多种途径进入环境,存在较大的环境影响及人身安全隐患,因此对其进行退役治理是势在必行。本文以西北地区某典型的铀矿地质勘探遗留的废石堆为研究对象,以砂质亚粘土作为覆盖材料,进行了相关覆土试验。主要研究了覆土厚度与氡析出率和γ辐射剂量率的变化关系;覆土压实度与氡扩散系数的变化关系。试验结果表明:本试验场地作为有限制开放场所的最佳覆土厚度为68cm,而作为无限制开放场所的最佳覆盖厚度不小于110cm;γ辐射剂量率随着覆土厚度的增大而急剧减小,在覆土厚度达到45cm时趋于稳定;氡扩散系数随着压实度的增大而减小;覆土厚度与氡析出率的关系符合。更多还原

【Abstract】 Before the decommissioning of the geological exploration facilities, the radionuclides have entered the environment through many ways. There are great environmental impacts and personal safety dangers, so it is imperative to do decommissioning treatment. In this paper, taking the waste stone pile left over from the geological exploration of a typical uranium deposit in Northwest China as the research object, using the sandy sub-clay for covering material, the related overlying soil test is carried out. In this study, soil covering experiments were performed, which used the sandy sub-clay to cover the waste stone pile of a typical geological exploration of uranium deposit in Northwest China. The effect of thickness of covering soil on the released rate of radon and dose rate of γ-radiation was investigated. The effect of compaction with covering soil on the radon diffusion coefficient was explored. The result indicated that the optimum covering soil thickness of the test site as restricted open place was 68 cm in the experiments, and that the optimum covering thickness of the test site as an unrestricted open place was not less than 110 cm in the experiments. The results showed that the dose rate of γ-radiation decreased sharply with the increase of the soil thickness, which was stable when the thickness of covering soil reached 45 cm. The results showed that the radon diffusion coefficient decreased with increasing of compaction degree. The relationship between the thickness of covering soil and radon exhalation rate is as.更多还原