Radon Surface Exhalation Research Articles

Environmental Radioactivity of Alpha in Paint samples of Iraqi Markets

By using a sealed technology, radon levels were determined, annual effective dose, the effective content of radium, radon exhalation rate and uranium concentrations to be the total 30 samples materials used to paint the walls of buildings and homes in Iraq. It was found that the recommended value for all samples for radon concentration is with low potency radium content of 300 Bq / m3 and 370 Bq / kg respectively. In addition, Annual effective dose in all values was found to be less than the permission level (10 mSv / y). The values of exhalation rate relative to samples lower than the permission value (57.600 mBq/m2.h) set by UNSCEAR organization. The strong correlation (R2=1). It turns out that the content effective radium with the surface radon exhalation rate, the mass radon exhalation rate, and the uranium concentration, respectively. In general, the studied of 30 samples materials used to paint the walls of buildings and homes in Iraq be safe to use as construction material.

Investigation of Gebze-Darıca metro line (Kocaeli Province/Turkey) in terms of radon and gamma radiation levels

In this study, 222Rn and gamma radiation levels were measured in soil and rock samples taken from Gebze - Darıca Metro Line, which is under construction, within the borders of Kocaeli province (Turkey), which is an important industrial city. Measurements were made in the summer of 2021 and are interpreted by environmental factors such as depth, humidity, temperature, air pressure and geological formations (granite and non-granite) that may affect radiation levels. It was observed that radon concentrations were in the range of 145–3696 Bqm−3 in measurements made on soil samples. The highest radon values in rocks were measured in granodiorite (3242.8 Bq m−3) and granite (2253.4 Bqm−3) samples. The amount of radionuclide and radon in soils is higher than in rocks. In the measurements made at 48 selected points, the World Health Organization (WHO) limit value was exceeded at 27 points in total (%56 of all samples). There are six measurement points exceeding the limit values for both public and employees, with the highest annual average effective dose (H) for radon concentration of 2.94–23.55 mSv y−1 at S11. The highest surface radon exhalation rate was calculated as 508.02 Bq m−2 h−1 at station S11. Indoor measurements at 20 cm below the soil surface range from 81 to 252 nSvh−1, and all but S5 exceed the indoor gamma dose rate level of 84 nGy h−1 worldwide. Effective dose level caused by the gamma radiation originating from the Earth's surface, specified in the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) (2000) report, is exceeded 0.5 mSv y−1 at all stations. In the statistical analyzes based on X-Ray Fluorescence (XRF) and X-Ray Diffraction (XRD) results, positive strong and moderate correlations were found between the average 222Rn concentration and weight percentage (Wt %) of K2O, Na2O, ThO2, ZrO2 oxides and Quartz, Montmorillonite, Albite minerals, respectively. Gamma radiation is correlated with Na2O Wt% content (R2 = 0.7056). A moderately negative correlation was found between the mean 222Rn concentration and temperature, a weak negative correlation with pressure, a weak positive correlation with humidity, and a moderately significant correlation with the presence of granite.

Experimental study on radon retardation effect of modular covering floats in radon-containing water

Radon-containing water bodies in uranium mining areas inevitably release radon gas, polluting the surrounding environment via radiation. Thus, it is particularly important to develop devices with the ability to retard the radon release from such water bodies. Based upon theories of radon exhalation in water, a radon exhalation retardation device (RERD) with flexible, modular floats (a flexible polyvinyl chloride material module that floats on water) was designed and manufactured. To study the modular surface-covering floats’ effectiveness in retarding radon release from water surfaces, an experimental setup was constructed to simulate radon release from water bodies, using a granular uranium ore sample from a uranium mine as sediment material. Closed-loop measurements were taken to determine the radon exhalation rate on the exposed surface of the water in uncovered and covered conditions. Radon retardation rates were also compared for different area coverage (29.6%, 59.1%, and 88.7%) and immersion depths (0.02 m and 0.04 m) in unperturbed and perturbed water bodies. The results show that: 1) the greater the area coverage, the greater the radon retardation rate in both unperturbed and perturbed water bodies; 2) under the same coverage conditions, the surface radon exhalation rate and the radon transfer velocity at the gas-liquid interface of the perturbed water are larger than those of the unperturbed water; 3) The immersion depth of modular surface-covering floats has a stronger effect on the radon retardation rate in unperturbed water bodies than in perturbed water bodies. The study shows that the proposed modular floats are effective in retarding radon release from both perturbed and unperturbed water bodies.

Mechanical, Structural, and Environmental Properties of Building Cements from Valorized Sewage Sludges

Building materials can enable the recycling of sewage sludge from tannery wastewater treatment by infiltration/percolation over coal and clay waste. The process avoids energy-intensive operations and yields a stable and environmentally friendly product. The sludge under study is mainly composed of SiO2, CaO, Al2O3, and Fe2O3, which is convenient to replace the mortar in cement. Different mortars were made by substituting a variable amount of sludge, from 0 to 30%, into the standard cement. The microstructure and mechanical properties of the mortar specimens were characterized after curing for 7 days and 28 days. The best properties were obtained with 15% sludge. Above 15%, the strength decreases at an early stage, as confirmed by SEM and XRD analysis, with more voids and ettringites at larger sludge content. The leaching tests of the mortar confirm that the cumulative values of heavy metals are far below the Deutsch regulatory limits (NEN 7043), justifying retention of the metals in the matrix. Radiological assessment of the sludge mortars also confirms their safety with the values of naturally occurring radioactive materials, surface radon exhalation and annual effective dose far below the required limits. The study suggests that 15% sludge can be used to sustainably replace cement and meet building safety requirement standards.

Evaluation and measurement methods for the surface radon exhalation rate of buildings

Half of the natural radiation dose to the human body comes from indoor radon and its progeny, inhaling of which plays a key role in the development of lung cancer. Given the relationship between the radon exhalation rate (RnER) and the indoor radon concentration, accurate determination and control of the former directly affect the control and protection of the latter. In this study, a method was developed to estimate the actual RnER of building walls through building material samples. The surface RnER of the wall of any thickness that was constructed of any building material could be calculated by its intrinsic RnER value and radon diffusion length, which could be obtained by measuring the RnER of the pre-treated building material sample models through the activated carbon box-γ spectroscopic method. The experimental results indicated that the deviation between the calculated wall surface RnER of the building and the measured wall surface RnER of the building was <5.1%. Therefore, the intrinsic RnER of building materials could be regarded as an evaluation index for the RnER of buildings.

Statistical Characterization of Damage of Different Surface P-Wave Velocity Sets under Dynamic Load and Study on Overall Radon Detection Consistency

Abstract On the basis of reviewing the existing research status of cumulative damage of the rock mass and summarizing the existing engineering application fields of radon, this paper attempts to apply radon detection technology to the research field of rock damage mechanics so as to monitor the evolution process of cumulative damage of the rock mass. Based on the above research purposes, a test device for detecting cumulative damage of radioactive rocks by surface radon gas was designed, and the test results were obtained by integrating the system to implement the test scheme. Due to the limitation of the nonmetallic ultrasonic detector, a single blasting damage value of 25 detection points appears after a single blasting measurement, which is a surface longitudinal wave velocity characterization damage set, while the surface radon exhalation rate in the subsequent analysis process is an overall characterization value; that is, the existence of damage directly affects the whole body radon exhalation rate of the test block, and the data dimensions of the two are different. In order to solve this problem, we try to introduce three data evaluation methods, the average weighting method, grey prediction method, and K-means clustering algorithm, and compare the feasibility of these three methods. It is proved that there is a certain linear relationship between the radon exhalation rate and the cumulative damage, which further verifies the feasibility of using radon to detect cumulative damage. The results show that the cumulative damage of loaded radioactive rock test blocks can be reflected by surface radon detection technology, and finally, the correlation between the cumulative damage characteristics and the continuous change of the body radon exhalation rate is obtained. Based on the correlation, the body radon exhalation rate is introduced into the field of fractured rock mass damage characterization, which is mutually improved with common monitoring methods such as acoustic emission and microseismic monitoring, supplementing and enriching the means of rock mass damage evolution characterization, providing a theoretical basis for finely describing the whole process of fracture closure and initiation, and finally accurately ensuring the stability of surrounding rock under the action of deep underground engineering excavation disturbance.

Analysis of equivalent thickness of geological media for lab-scale study of radon exhalation.

Geological media are omnipresent in nature. Lab-scale tests are frequently employed in radon exhalation measurements for these media. Thus, it is critical to find the thickness of the medium at an experimental scale that is equivalent to the medium thickness in a real geological system. Based on the diffusion-advection transport of radon, theoretical models of the surface radon exhalation rate for homogeneous semi-infinite and finite-thickness systems were derived (denoted as Jse and Jfi, respectively). Analysis of the equivalency of Jse and Jfi was subsequently carried out by introducing several dimensionless parameters, including the ratio of the exhalation rates for the semi-infinite and finite-thickness models, ε, and the number of diffusion lengths required to achieve a desired ε value, n. The results showed that when radon transport in geological media is dominantly driven by diffusion effect, if n > 3.6626, then ε > 95%; if n > 5.9790, then ε > 99.5%. When radon migration is dominantly driven by advection effect, if n > 2.5002, then ε > 95%; if n > 4.0152, then ε > 99.5%. Therefore, if the thickness of the geological media (x0) is greater than a certain n times the radon diffusion length of the media (L), the media can be modeled as semi-infinite. To validate the model, a pure radon diffusion experiment (no advection) was developed using uranium mill tailings, laterite, and radium-bearing rocklike material with different thicknesses (x0). The theoretical model was demonstrated to be reliable and valid. This study provides a basis for determining the appropriate thickness of geological media in lab-scale radon exhalation measurement experiments with open bottom.

Radiological survey on radon entry path in an underground mine and implementation of an optimized mitigation system

BackgroundThe European Union council has introduced the basic safety standards (EU-BSS) for protection against the dangers arising from exposure to ionizing radiation by laying down a new radon reference level at workplaces. In this regard, all European state members must establish a national reference level based on all pre-defined requirements. After implanting the directive 2013/59/Euratom by European state members, new challenges have been revealed to mitigate radon appropriately in underground workplaces due to the exciting limitations (e.g., ventilation system, dust dispersion, air injection, etc.). Therefore, a conceptual design of an environmental radiological survey was defined and implemented by examining the hypothesis to find practical solutions following EU-BSS. The main objectives of this study were to identify the potential radon entry paths, utilize an optimized ventilation system, and carry on long-term radon monitoring in an operational underground manganese mine.ResultsThe mullock rocks (the geological structure of the mine walls) contained a small amount of Ra-226 (2–4 Bq kg−1). On the other hand, the mine ore (black shale, underlayer black shale, and carbonate ore) has shown the highest concentration of Ra-226 (12–16 Bq kg−1) and the highest radon exhalation (1.2–1.6 mBq s−1 m−2). The surface radon exhalation from the mine walls was in the range of 0.7 ± 0.1 and 1.5 ± 0.2 mBq m−2 s−1. It was found that shortly after mining activity was undertaken, radon concentration increased dramatically with an average of about 5900 ± 420 Bq m−3 near the freshly broken walls. The optimized mobile mitigation system reduced radon concentration to 250 ± 41 Bq m−3 on average.ConclusionApart from the fact that aged walls were involved in the radon accumulation, considering the mine ventilation performance and the total active surface area, the exhaled radon from the aged walls could not be the primary potential source of high radon concentration when mining activity was undertaken. According to the obtained results, the ores, recently fragmented during the course of mining operations, were the primary path. Therefore, after successfully identifying the radon entry path, radon concentration could be reduced to meet the EU-BSS requirement by implementing the developed mitigation system.

Measurement and spatial distribution pattern of natural radioactivity in a uranium tailings pond in Northwest China

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.

Applicability of the closed-circuit accumulation chamber technique to measure radon surface exhalation rate under laboratory conditions

A layer of phosphogypsum was placed at the bottom of two large volume boxes. This system allowed to measure the surface radon exhalation from phosphogypsum without altering the emitting material. The limits and optimal setup of the closed-circuit accumulation chamber technique were thoroughly studied. More precisely, the performance of different radon exhalation fitting methods was analyzed in the reference exhalation boxes, employing different measurement devices and three smaller operational accumulation chambers. As expected, the best approach to obtain the radon exhalation rate depends upon the effective decay constant of the measurement system and the time employed to perform the measurement. The time until the linear approximation can no longer be applied was scrutinized. Although this approximation is usually applied routinely in the literature, the effective time constant of the chamber is often not low enough for the linear fit to be applied safely, providing statistically acceptable measurements that can lead to significative underestimations of the radon exhalation rate.

Influence of the accumulation chamber insertion depth to measure surface radon exhalation rates

A common method to measure radon exhalation rates relies on the accumulation chamber technique. Usually, this approach only considers one-dimensional gas transport within the soil that neglects lateral diffusion. However, this lateral transport could reduce the reliability of the method. In this work, several cylindrical-shaped accumulation chambers were built with different heights to test if the insertion depth of the chamber into the soil improves the reliability of the method and, in that case, if it could limit the radon lateral diffusion effects. To check this hypothesis in laboratory, two reference exhalation boxes were manufactured using phosphogypsum from a repository located nearby the city of Huelva, in the southwest of Spain. Laboratory experiments showed that insertion depth had a deep impact in reducing the effective decay constant of the system, extending the interval where the linear fitting can be applied, and consistently obtaining reliable exhalation measurements once a minimum insertion depth is employed. Field experiments carried out in the phosphogypsum repository showed that increasing the insertion depth could reduce the influence of external effects, increasing the repeatability of the method. These experiments provided a method to obtain consistent radon exhalation measurements over the phosphogypsum repository.

A method for radiologically evaluating indoor use of dimension stone considering radon exhalation rates

Background: The use of natural radioactive building materials could be a health risk for both dwellers and mining workers. Therefore, a quick and effective method to test batches of rock samples is needed. Nevertheless, there is no reference value for maximum exhalation rates for building materials, except radiological hazard indices that do not measure gas exhalation rates directly. Objectives: This article investigated the correlations between Gamma Index and radon and thoron exhalation rates, and the proportions of radon and thoron in samples. Moreover, the main objectives were to analyze the feasibility of screening problematic samples for indoor use through a portable radiation detector (CoMo 170), which consists of a quick analysis at very low cost, and to simulate indoor concentration of radon using the measured exhalation rates of dimension stone slabs. Design: Best-selling dimension stone slabs were submitted to the following assays: gamma spectrometry, radon and thoron exhalation analysis using scintillation cell, and radioactivity measurement using a portable detector. Univariate and multivariate statistical analyses were conducted using Statistica 13 software. Results: The average activity concentrations measured were 971 ± 58.6 Bq/kg of 40K, 184 ± 9 Bq/kg of 232Th, and 74 ± 3 Bq/kg of 226Ra. The maximum activity concentrations of 40K, 232Th, and 226Ra series were 1,734 ± 100 Bq/kg, 2,667 ± 109 Bq/kg, and 596 ± 2 Bq/kg, respectively. The average exhalation rate of 222Rn was 406 ± 20 Bq/h m2. Conclusions: The main recommendations arising from this study are as follows: a portable radiation detector (CoMo 170) could be used as a screening method for selected samples; Gamma Index limit value = 1 for dimension stone slabs could be adopted when assessing radon and thoron exhalation; and the surface radon exhalation rate should be measured as a basis of recommendation for surface treatment before sales. Finally, thoron exhalations should be considered in radiological assessment, as 57% of the samples had higher thoron exhalation rates than radon.

Experimental study of the effect of water level and wind speed on radon exhalation of uranium tailings from heap leaching uranium mines.

Water level and wind speed have important influences on radon release in particle-packing emanation media. Based on radon migration theory in porous media under three water level conditions, an experimental setup was designed to measure the surface radon exhalation rate of uranium tailings from heap leaching uranium mine at different water levels and wind speeds. When the water level was at 0.3 m (overlying depth 0.05 m), radon transfer velocities at the gas-liquid interface were also measured at different wind speeds. Results show that when the water level was equal to or lower than the surface of the sample, the radon exhalation rate increased with increasing wind speed and decreased with increasing water level. When the water level was higher than the surface of the sample, radon exhalation rate of the water surface increased with increasing surface wind speed. The wind speed, however, was less influential on the radon exhalation rate as the depth of the overlying water increased, with a dramatic decrease in radon release. That said, at different wind speeds, radon transfer velocities at the gas-liquid interface were consistent with literature. On the other hand, changes in wind speed had significant influences on the radon transfer velocity at the gas-liquid interface, with the effect less pronounced at higher wind speeds.

Experimental study on radon exhalation behavior of heap leaching uranium ore column with dilute sulfuric acid.

In order to study the radon release behavior when heap leaching uranium ores with dilute sulfuric acid, unleached uranium ores from a uranium mine in southern China were selected as test samples. Adopting parameters from leaching processes commonly used in uranium mines, a laboratory experiment was carried out for 21days with a one-dimensional acid heap leaching experimental column. The surface radon exhalation rate of uranium ore column was determined by static accumulation method while spraying with deionized water and dilute sulfuric acid. The uranium leaching rate and ore column height for all 21days of the experiment were also measured. The results show that (1) when sprayed with a leaching agent, the surface radon exhalation rate of uranium ore column initially increased with time sharply. After a maximum value was reached, the rate gradually decreased and stabilized. When the spraying stopped, the surface radon exhalation rate of uranium ore column initially decreased, before increasing until it tended to stabilize. (2) During the entirety of the 21-day leaching experiment, the cumulative leaching rate of uranium increased gradually with time. On the other hand, the surface radon exhalation rate of uranium ore column fluctuated, but the leaching of uranium from uranium ores had almost no effect on the radon exhalation rate. (3) There was no linear correlation between the surface radon exhalation rate and the residual height of ore column during leaching, but the collapsing event of ore column was the direct inducing factor of the fluctuation of surface radon exhalation rate.

Compressive strength, water absorption, water sorptivity and surface radon exhalation rate of silica fume and fly ash based mortar

In this study, the effect of partial cement replacement with silica fume and fly ash on the compressive strength, water absorption, volume of permeable pore, water sorptivity, radon content and surface radon exhalation rate of mortar mixtures were investigated. It was observed that the compressive strength of mortar mixtures containing silica fume as partial cement replacement increased as the amount of silica fume content increased while the water absorption, volume of permeable pore, water sorptivity and radon exhalation rate of mortar mixtures decreased. The decrease in surface radon exhalation rate was ranged between 23% and 43% while that of mortar mixtures containing fly ash increased up to 15% of the rate of the control mortar mixture. Results showed that silica fume addition decreased the radon concentration and surface radon exhalation rate while fly ash showed a detrimental effect.

Radon exhalation rate and radon activity in soils of riverine environs of South Karnataka

In the present study, sealed “can technique” using solid-state nuclear track detector (LR-115) films was employed to measure the radon exhalation rate and radium concentration in soil samples of Cauvery river environment. The mean values of radon activity, radon surface exhalation, and mass exhalation are 216.15 Bq m−3, 521.08 Bq m−1 h−1, and 247.21 mBq kg−1 h−1, respectively. The radium activity concentration and radon exhalation show good correlation.

Natural radioactivity in some building materials and assessment of the associated radiation hazards

Abstract The results of the specific activities of 232Th, 226Ra and 40K measured in samples of commonly used building materials in Bosnia and Herzegovina are presented. Measurements were performed by gamma-ray spectrometer with coaxial HPGe detector. The surface radon exhalation and mass exhalation rates for selected building materials were also measured. The determined values of specific activities were in range from 3.16±0.81 Bq kg−1 to 64.79±6.16 Bq kg−1 for 232Th, from 2.46±0.95 Bq kg−1 to 53.89 ±3.67 Bq kg−1 for 226Ra and from 28.44±7.28 Bq kg−1 to 557.30±93.38 Bq kg−1 for 40K. The radium equivalent activity, the activity concentration index, the external and internal hazard indices as well as the absorbed dose rate in indoor air and the corresponding annual effective dose, due to gamma-ray emission from the radioactive nuclides in the building material, were evaluated in order to assess the radiation hazards for people. The measured specific activities of the natural radioactive nuclides in all investigated building materials were compared with the published results for building materials from other European countries. It can be noted that the results from this study are similar to the data for building materials from neighbouring countries and for building materials used in the EU Member States. The radiological hazard parameters of the building materials were all within the recommended limits for safety use.

Influence of architectural style on indoor radon concentration in a radon prone area: A case study

Indoor radon is a major health concern as it is a known carcinogenic. Nowadays there is a trend towards a greater energy conservation in buildings, which is reflected in an increasing number of regulations. But, can this trend increase the indoor radon concentration? In this paper, we selected a radon prone area in Spain and focused on single-family dwellings constructed in a variety of architectural styles. These styles ranged from 1729 up to 2014, with varying construction techniques (from local resources to almost universally standard building materials) and regulations in force (from none to the Spanish regulation in force). The 226Ra concentrations in soil and surface radon exhalation rates were rather similar in this area, mean values ranging 70–126Bq/kg and 49–100mBq/m2·s, respectively. Indoor radon concentration was generally greater than the contribution from soil exhalation (surface exhalation rates), especially in New dwellings (1980–2014). Its concentration in dwellings built in the Traditional style (1729–1940) was significantly lower than in the new houses. This can be consequence of the air tightness of the dwellings as a consequence of the different regulations in force. In the period covered by the Traditional style, there was no regulation in force, and dwelling had loose air tight. Whereas in recent times, there are mandatory regulations assuring a better air tightness of the buildings. Refurbishment of Traditional dwellings also seems to increase the indoor radon concentration, as they must also comply with the regulations in force.

Radon Level Measurements in Soil and Sediments at Oil Field Area and Its Impact on the Environment

Radon concentration, radium content, uranium concentration and rates of radon exhalation as a function of mass and area in 10 soil and 5 water sediment samples collected from one of the oil fields in Basrah governorate southern Iraq using CR-39 SSNTD were measured. Obtained results of radon concentrations range from 434.67 Bq.m-3 to 1947.99 Bq.m-3 with mean value of 985.26 Bq.m-3 and from 61.18 Bq.m-3 to of 2237.77 Bq.m-3 with mean value of 1215.16 Bq.m-3 in sediment and soil samples, respectively. The values of radium content for sediment and soil samples extended from 1.96 Bq.kg-1 to 9.75 Bq.kg-1, with an average value of 4.45 Bq.kg-1 and from 0.28 Bqkg-1 to 10.11 Bq.kg-1 with mean value of 5.49 Bqkg-1, respectively. Uranium concentration in ppm was calculated and its values were found to range from 0.36 to 13.07 ppm, which are comparable with different places around the world. The mass and surface radon exhalation rates vary from 0.079 Bqkg-1h-1 to 2.88 Bqkg-1h-1 with a mean value of 1.41 Bqkg-1h-1, and from 1.37 Bqm-2h-1 to 49.98 Bqm-2h-1 with a mean value of 24.47 Bqm-2h-1, respectively. Radium content is observed to be positively correlated with uranium concentration and with rates of radon exhalation in the study area, respectively.

Measurement of Natural Radioactivity and Radon Exhalation Rate in Coal Ash Samples from a Thermal Power Plant

Coal is the main energy source for electricity generation in the world. In Morocco, 37% of electricity generation comes from combustion coal in thermal power plants. This combustion process generates large amounts of fly and bottom ashes. In recent years, these ashes became a great topic of interest because of their different uses and especially in construction materials. In this work, we assess radiation risks due to natural radioactivity in samples of fly and bottom ashes collected from JLEC (Jorf Lasfar Energy Company) thermal power plant, and different analyses are performed through two nuclear techniques such as gamma spectrometry and alpha dosimetry based on the use of LR115 films detectors. Our analysis shows that 226 Ra activities and 232 Th in both ash samples are well above the permissible activity. The values of the external risk index (Hex) and internal one (Hin) for these ashes are below unity, with the exception of 1.28 in fly ash for Hin. The obtained values for the equivalent radium Raeq and annual effective doses Ė in fly and bottom ashes are 324 Bq/kg and 210 Bq/kg, and 0.18 mSv/y and 0.11 mSv/y, respectively. The surface radon exhalation rates for the samples of fly and bottom ashes are 276 mBq • m −2 • h −1 and 381 mBq • m −2 • h −1 , respectively. Based on these results, we have shown that fly ash and bottom one from thermal power plant JLEC didn't have, in any case, a health risk to the public so it can be effectively used in various construction activities.