[en] This paper describes the construction of RIUM radon chamber, gives it's performance index and accuracy, and outlines the verification, calibration and examination of monitors of radon and it's daughter for ten years since the construction. In addition, today and tomorrow of RIUM radon chamber are presented. (author)

[en] The Measurement of radon decay products concentration in air has particular problem in two calibration factors: (1) Detection efficiency for a filter sample. It can't be determined by a standard source with a given activity of radon decay products because of the short life of radon decay products. A common α standard source has to be used as a substitute. (2) Flow rate of air sampling. It prevent the radon decay products (aerosol particles) from plate-out in flowmeter before filtering. So, the flowmeter should work in a lower pressure than the ambient air because of the pressure decrease through the filter, and it's readings have to be corrected. In order to accurately determine the calibration factors mentioned above, care has been taken on installation, adjustment, calibration and correction of the sampling and measuring system. A series of tests have also be made to confirm: (1) whether the detection efficiency is independent of the energy of α-particle, (2) the counting loss of the α particle with energy lower than that limited by the instrument threshold is negligible, (3) whether the counting efficiency is equal to the geometry factor. Consequently, the systematic uncertainty of the sampling and measuring system reduced to 2% and the random uncertainty (other than counting statistics) reduced to 1%. This system has been successfully used in our calibration and test facility for radon and radon daughters (RIUM radon chamber)

[en] The personal dose of uranium miners in China used to be estimated by area monitoring. Since 1998, the passive personal dosimeter (Model KF-606, developed in RIUM) has come into routine use in an uranium mine. (authors)

[en] This paper presents the results of indoor Rn levels measured using CR-39 solid state nuclear track detector in 4 areas in Hunan Province, south China. Statistical test results indicate that radon concentrations in this 4 areas exhibit log-normal distribution. From a geographical perspective, radon concentrations in these areas are high in north-west and low in south-east. This is indicative that geological formation and building materials have influence on indoor radon concentration. (authors)

[en] Short communication

[en] To address the problems of high uranium ore grade, huge radon emission and radon contamination to inline tunnel in one trackless mining uranium mine, the radon contamination situation has been analyzed in this report. By the method of adjustment of pressure distribution and building of negative pressure channel, radon releases from main radon source have been collected to return air system. Emission radon from radon source is effectively controlled. The purpose of reducing radon concentration is reached. The miner's total effective dose is decreased from 58.52, mSv/a to 13.3 mSv/a. (authors)

[en] A nation-wide intercomparison of radon integrating detectors (activated charcoal, track etch and thermoluminescence, et al.) which 12 participants were involved was conducted at Research Institute of Uranium Mining (RIUM) in China in 1989. The participants intercompared their detectors under 6 exposure conditions (low and high radon concentration, humidity and temperature) provided by RIUM radon chamber. Most of detectors showed a quite good reproducibility. Exposure conditions seem to have influence on some detectors which application conditions could not be considered thoroughly. Calibration of some detectors appeared to pose problems. (Author)

[en] According to the pit arrangement features of trackless mining uranium mine, based on the fundamental of radon permeation and control, and analysis of radon pollution characteristics and radon education, the design principle of ventilation system in trackless mining uranium mine has been raised

[en] Mine Ventilation is the most important way in lowering radon of uranium mines. At present, radon and radon daughter concentration of underground air is 3∼5 times higher than any other air concentration of foreign uranium mines, as the same input for Protective Ventilation between Chinese uranium mines with compaction methodology and international advanced uranium mines. In this passage, through the analysis of Ventilation Radon Reduction status in Chinese uranium mines and the comparison of advantages and shortcomings between variety of ventilation and radon reduction, it illuminated the reasons of higher radon and radon daughter concentration in Chinese uranium mines and put forward some problems in three aspects, which are Ventilation Radon Reduction Theory, Ventilation Radon Reduction Measures and Ventilation Management. And to above problems, this passage put forward some proposals and measures about some aspects, such as strengthen examination and verification and monitoring practical situation, making clear ventilation plan, in according to mining sequence strictly, training Ventilation technician forcefully, enhance Ventilation System management, development of Ventilation Radon Reduction technology research in uranium mines and carrying out ventilation equipments as soon as possible in further and so on. (authors)

[en] Mine ventilation is the most important way to reduce radon in uranium mines. At present, the concentrations of radon and its daughters in underground air is 3-5 times higher than those in other countries, at the same protection conditions. In this paper, through the analysis of radon reduction status in Chinese uranium mines and the comparison of advantages and shortcomings between variety of ventilation and radon reduction measures, the reasons for higher radon and radon daughter concentration in Chinese uranium mines are discussed and some problems are put forward in three aspects: radon reduction ventilation theory, measures and management. Based on above problems, this paper puts forward some proposals and measures, such as strengthening examination and verification and monitoring practical situation, making clear ventilation plan, training ventilation technician, enhancing ventilation system management, developing radon reduction ventilation research and putting ventilation equipment in place as soon as possible in future. (authors)