ABSTRACT

Numbers of radioactive tailings were produced in the process of uranium mining and milling.In this study,radiation environment monitoring was carried out on a decommissioned uranium mining and milling tailings pond in northwest China, and the governance effect and operation status of the tailings pond was investigated. The soil radionuclide activity concentration and ambient dose equivalent rate (H^*(10)) were measured, and soil surface radon exhalation rate was calculated. The results shown that in the tailings pond and its surrounding area, the average soil radionuclide activity concentration was respectively ²³⁸U: 42.64±11.17 Bq·kg^-1, ²²⁶Ra: 45.47±13.56 Bq·kg^-1, ²³²Th: 33.30±7.33 Bq·kg^-1, ⁴⁰K: 631.33±72.05 Bq·kg^-1, the average H^*(10) was 63.32±6.46 nSv·h^-1, and the average radon exhalation rate was 40.46±11.29 mBq·m^-2·s^-1.Radionuclide activity concentration, H^*(10) and radon exhalation rate were within the range of world natural background. Spatial distribution of radioactivity was analyzed by OK interpolation based on the investigated data. According to the measured results and spatial interpolation analysis,the decommissioning governance effect of the uranium tailings reservoir is good, the operation is normal, and there is no migration or diffusion situation of radionuclides in the pond has been found.

摘要

铀矿选冶过程中产生了大量放射性尾矿。本研究对西北某退役铀矿选冶尾矿库进行了辐射环境监测，对该尾矿库的治理效果和运行状况进行了监测。调查。测量土壤放射性核素活度浓度和环境剂量当量率（H ^*（10）），计算土壤表面氡呼出率。结果表明，尾矿库及周边区域土壤放射性核素平均活度浓度分别为 ²³⁸ U：42.64±11.17 Bq·kg ^-1、  ²²⁶ Ra：45.47±13.56 Bq·kg ^-1、  ²³²Th：33.30±7.33 Bq·kg ^-1，  ⁴⁰ K：631.33±72.05 Bq·kg ^-1，平均H ^* (10) 为63.32±6.46 nSv·h ^-1，平均氡呼出率为40.496±11。 mBq·m ^-2 ·s ^{-1 .}放射性核素活度浓度，H ^*(10) 和氡呼出率均在世界自然本底范围内。基于调查数据通过OK插值分析放射性的空间分布。根据实测结果和空间插值分析，铀尾矿库退役治理效果良好，运行正常，未发现池内放射性核素迁移或扩散情况。