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41.
研究RAD7测氡仪对空气中氡浓度测量的不确定度;通过标准氡室模拟不同的氡浓度,对该测氡仪在标准条件下测量的不确定度进行研究;取包含因子k=2时,在模拟的两种氡浓度情况下得到的该测氡仪不确定度分别为14.38%和14.52%;该测氡仪达到GB50325-2001中对空气中氡检测方法的测量不确定度的要求。 相似文献
42.
Quindós Poncela LS Fernández PL Gómez Arozamena J Sainz C Fernández JA Suarez Mahou E Martin Matarranz JL Cascón MC 《Environment international》2004,29(8):1091-1096
During the last decade, the Department of Applied and Medical Physics has been involved in the development of a radiation protection programme. In the framework of this programme, measurements of indoor radon, principally, have been carried out nationwide. Geometric mean radon concentrations of 45 Bq m(-3) in the whole country and 130 Bq m(-3) in the high natural radiation area have been estimated. On the other hand, the so-called MARNA Project is developed into the framework of an agreement subscribed between the Spanish Nuclear Safety Council (CSN) and the National Uranium (ENUSA), the first phase of which has been the elaboration of the Natural Gamma Radiation Map of Spain on the scale of 1:1,000,000 using radiometric data generated in the 30 years of the lifetime of the ancient National Uranium Exploration and Investigation Plan mainly through airborne, carborne, and by foot surveys, within the MARNA Project itself. The lowest averaged dose rate from external gamma radiation (19.3 nGyh(-1)) was found in carbonate bedrock and the highest (87.7 nGyh(-1)) was found in granite and clay bedrock. This paper summarizes the main results obtained from the measurements performed in both projects, with special interest in those concerning the correlation between the data reported in order to conclude about the potential benefit of the MARNA maps in the definition of affected areas in the country. 相似文献
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44.
Kávási N Vigh T Kovács T Vaupotič J Jobbágy V Ishikawa T Yonehara H 《Journal of environmental radioactivity》2011,102(9):806-812
One of the essential parameters influencing of the dose conversion factor is the ratio of unattached short-lived radon progeny. This may differ from the value identified for indoor conditions when considering special workplaces such as mines. Inevitably, application of the dose conversion factors used in surface workplaces considerably reduces the reliability of dose estimation in the case of mines.This paper surveyed the concentration of radon and its short-lived radon progeny and identified the unattached fraction of short-lived radon progeny. As well equilibrium factor during the month of August was calculated simultaneously at two extraction faces in a manganese ore mine.During working hours the average radon concentrations were 220 Bq m−3 and 530 Bq m−3 at Faces 1 and 2; the average short-lived progeny concentration was 90 Bq m−3 and 190 Bq m−3, the average equilibrium factors were 0.46 and 0.36, and the average unattached fractions were 0.21 and 0.17, respectively. The calculated dose conversion factor was between 9 and 27 mSv WLM−1, but higher values could also be possible. 相似文献
45.
Obed RI Ademola AK Vascotto M Giannini G 《Journal of environmental radioactivity》2011,102(11):1012-1017
Radon measurements were performed in secondary schools in the Oke-Ogun area, South-west, Nigeria, by solid state nuclear track detectors (SSNTDs). About seventy CR-39 detectors were distributed in 35 high schools of the Oke-Ogun area. The CR-39 detectors were exposed in the schools for 3 months and then etched in NaOH 6 N solution at 90 °C for 3 h. The tracks were counted manually at the microscope and the radon concentration was determined at the Radioactivity Laboratory, Department of Physics, University of Trieste, Trieste, Italy. The overall average radon concentration in the surveyed area was 45 ± 27 Bq m−3. The results indicate no radiological health hazard. The research also focused on parameters affecting radon concentrations such as the age of the building in relation to building materials and floor number of the classrooms. The results show that radon concentrations in ground floors are higher than in upper floors. 相似文献
46.
Gal F Joublin F Haas H Jean-Prost V Ruffier V 《Journal of environmental radioactivity》2011,102(2):107-118
The south east basin of France shelters deep CO2 reservoirs often studied with the aim of better constraining geological CO2 storage operations. Here we present new soil gas data, completing an existing dataset (CO2, 222Rn, 4He), together with mineralogical and physical characterisations of soil columns, in an attempt to better understand the spatial distribution of gas concentrations in the soils and to rule on the sealed character of the CO2 reservoir at present time.Anomalous gas concentrations were found but did not appear to be clearly related to geological structures that may drain deep gases up to the surface, implying a dominant influence of near surface processes as indicated by carbon isotope ratios. Coarse grained, quartz-rich soils favoured the existence of high CO2 concentrations. Fine grained clayey soils preferentially favoured the existence of 222Rn but not CO2. Soil formations did not act as barriers preventing gas migrations in soils, either due to water content or due to mineralogical composition. No abundant leakage from the Montmiral reservoir can be highlighted by the measurements, even near the exploitation well. As good correlation between CO2 and 222Rn concentrations still exist, it is suggested that 222Rn migration is also CO2 dependent in non-leaking areas - diffusion dominated systems. 相似文献
47.
Samuelsson C 《Journal of environmental radioactivity》2011,102(5):531-533
Any confined air volume holding radon (222Rn) gas bears a memory of past radon concentrations due to 210Pb (T1/2 = 22 y) and its progenies entrapped in all solid objects in the volume. The efforts of quantifying past radon exposures by means of the left-behind long-lived radon progenies started in 1987 with this author’s unsuccessful trials of removing 214Po from radon exposed glass objects. In this contribution the history and different techniques of assessing radon exposure to man in retrospect will be overviewed. The main focus will be on the implantation of alpha recoils into glass surfaces, but also potential traps in radon dwellings will be discussed. It is concluded that for a successful retrospective application, three crucial imperatives must be met, i.e. firstly, the object must persistently store a certain fraction of the created 210Pb atoms, secondly, be resistant over decades towards disturbances from the outside and thirdly, all 210Pb atoms analysed must originate from airborne radon only.For large-scale radon epidemiological studies, non-destructive and inexpensive measurement techniques are essential. Large-scale studies cannot be based on objects rarely found in dwellings or not available for measurements 相似文献
48.
Radon adsorption by activated charcoal collectors such as PicoRad radon detectors is known to be largely affected by temperature and relative humidity. Quantitative models are, however, still needed for accurate radon estimation in a variable environment. Here we introduce a temperature calibration formula based on the gas adsorption theory to evaluate the radon concentration in air from the average temperature, collection time, and liquid scintillation count rate. On the basis of calibration experiments done by using the 25 m3 radon chamber available at the National Institute of Radiological Sciences in Japan, we found that the radon adsorption efficiency may vary up to a factor of two for temperatures typical of indoor conditions. We expect our results to be useful for establishing standardized protocols for optimized radon assessment in dwellings and workplaces. 相似文献
49.
It is shown in this work that parameters of the Jacobi model, which describes behavior of short-lived radon progeny, are not independent. The relationship between deposition rate of attached radon progeny and attachment rate of their unattached fraction was determined in this paper. It was found that deposition rate increases when the attachment rate is smaller; this effect is more pronounced for larger friction velocity. The deposition rate of attached radon progeny is presented here as a function of friction velocity, ventilation and attachment rate. Deposition rate of attached fraction was estimated in the range 0.012-0.46 h−1, when attachment rate varies from 10 h−1 to 100 h−1. 相似文献
50.
Mapping of the geogenic radon potential in France to improve radon risk management: methodology and first application to region Bourgogne 总被引:2,自引:0,他引:2
In order to improve regulatory tools for radon risk management in France, a harmonised methodology to derive a single map of the geogenic radon potential has been developed. This approach consists of determining the capacity of the geological units to produce radon and to facilitate its transfer to the atmosphere, based on the interpretation of existing geological data. This approach is firstly based on a classification of the geological units according to their uranium (U) content, to create a radon source potential map. This initial map is then improved by taking into account the main additional parameters, such as fault lines, which control the preferential pathways of radon through the ground and which can increase the radon levels in soils. The implementation of this methodology to the whole French territory is currently in progress. We present here the results obtained in one region (Bourgogne, Massif Central) which displays significant variations of the geogenic radon potential. The map obtained leads to a more precise zoning than the scale of the existing map of radon priority areas currently based solely on administrative boundaries. 相似文献