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The purpose of this work is to assess accuracy and compare the performance of radionuclide calibrators (RNCs) used in nuclear medicine departments in Serbia. Testing of the RNCs included verification of measurement accuracy, as well as analysis of routinely used quality control protocols, by using the certified radioactivity standards (57Co, 137Cs). RNCs performances were assessed with 99mTc through comparison of reference value for radionuclide activity and RNC measurements. Results of the intercomparison revealed that RNCs, 15 in total, are accurate within 10% in vial geometry and within 15% in syringe geometry. Most of them showed similar performance. The results revealed that container geometry is an important influencing parameter in the accuracy of activity measurement. Obtained results indicate a need for regular calibration and implementation of Quality Control program in order to achieve and maintain the accuracy of activity measurements in nuclear medicine.

Doses from the exposure to outdoor radon are typically an order of magnitude smaller than those from indoor radon, causing a greater interest on investigation of the latter for radiation protection issues. As a consequence, assessment of radon priority areas (RPA) is mainly based on indoor radon measurements. Outdoor radon measurements might be needed to guarantee a complete estimation of radiological risk and may help to improve the estimation of RPA. Therefore, authors have analysed the available literature on outdoor radon to give an overview of outdoor radon surveys and potential correlation with indoor radon and estimation of RPA. The review has shown that outdoor radon surveys were performed at much smaller scale compared to indoor radon. Only a few outdoor radon maps were produced, with a much smaller density, covering a larger area, and therefore putting doubt on the representativeness of this data. Due to a large variety of techniques used for outdoor radon measurements and requirement to have detectors with a high sensitivity and resistance to harsh environmental conditions, a standardised measurement protocol should be derived. This is no simple endeavour since there are more applications in different scientific disciplines for outdoor radon measurements compared to indoor radon.

Metodom gamaspektrometrije u periodu 2020-2021. godina praćena je koncentracija aktivnosti radionuklida u površinskoj vodi i rečnom sedimentu reke Dunav, na teritoriji beogradske opštine Zemun. U ovom radu su prikazane vrednosti izmerenih koncentracija aktivnosti detektovanih radionuklida. Dok se u uzorcima površinske vode praktično detektuje samo prisustvo 40K i 226Ra u koncentracijama reda nekoliko desetina mBq/l, u uzorcima sedimenta detektovani su prirodni radionuklidi u navedenim opsezima koncentracija : 226Ra - (14-46) Bq/kg, 232Th - (17-56) Bq/kg, 40K - (230-645) Bq/kg, 238U - (15-53) Bq/kg i 235U - (1,2-3,2) Bq/kg.

The operation of coal fired power plants greatly influences the surrounding environment, especially water and soil, due to large amounts of combustion waste products released. Besides the quality of soil and water from the aspect of chemical and structural composition (release of heavy metals, ash and slag deposition on soil) it is of at most importance to maintain a strict control from the radiological safety point of view. All coal types contain certain amount of naturally occurring radionuclides, which depends on the composition of the rock and soil adjacent to the place of the coal excavation. These radionuclides are concentrated in the process of coal combustion, thus leading to potentially high levels of radioactivity in the ash and slag. These by – products are released into the environment and can increase the radiation burden on the environment, change the composition of the soil and bodies of water in the vicinity, thus potentially influencing the health of the general population. In this paper, the radiological analysis of soil and water samples taken from the vicinity of different coal fired power plants in Serbia in the period of 2019-2021. will be presented. Measurements are performed in the Radiation and Environmental Protection Department of Institute of Nuclear Sciences Vinča within the framework of regular environment monitoring of the power plants.

Radiostrontium is released to the environment during the testing and use of nuclear weapons mainly in the fifties and sixties of XX century, in addition to nuclear power plant accidents (to some extent in 1986 owing to the Chernobyl accident) and the nuclear fuel reprocessing industry. Strontium is a chemical analogue of calcium (both are earth-alkaline metals) and accordingly when entering a human or animal body, it behaves similar to calcium. A large portion of the strontium will accumulate in bone and teeth and then is included in the metabolism along with Ca, and like calcium, it transfers to milk. Since the strontium uptake by the human body from milk is an important pathway for radiostrontium incorporation, milk and dairy products are good indicators of strontium-90 (Sr-90) content in human diet. Based on the mentioned, the knowledge about Sr-90 content in milk and dairy products is of extreme importance to prevent and control contamination of the food chain. The present study was conducted in order to radiologically control for Sr-90 content in raw milk and some dairy products samples composed of representative locally purchased milk. The analyses are performed using radiochemical analytical oxalate precipitation method, whereby interfering radionuclides are removed by precipitation scavenging. Yttrium-90 (Y-90) is generated from the beta decay of Sr-90. After the ingrowth Y-90 is separated and equilibrium is established, the samples are measured by gas flow proportional counter. The results of investigation showed that Sr-90 activity concentration in many investigated samples was at a lower level than minimum detectable activity (MDA) of the method.

After the Chernobyl accident, the presence of artificial radionuclides in foodstuff, especially in berries (blueberries, cranberries etc.), was heightened. Legislative, presented in Rulebook on Radioactivity Control of Goods During the Import, Export and Transit (Official Gazette RS, 86/19 and 90/19), establishes the mandatory gamma spectrometry measurement of berries, while the limits of radionuclide content in these products is defined in the Rulebook on Limits of radionuclide content in drinking water, foodstuff, feedstuff, medicines, items of general use, building materials and other goods placed on the market (Official Gazette RS, 36/18). At the Radiation and Environment Protection Department of the Vinča Institute of Nuclear Sciences, measurements of the radionuclide activity in foodstuff are readily performed. In this paper, the results of the investigation of berries in the period of 2014 to 2021 are presented along with the amount of this produce that can be ingested by the various age groups without exceeding the annual effective dose limit of 0.1 mSv.

In accordance with ISO/IEC 17025:2017 - General requirements for the competence of testing and calibration laboratories, the laboratory needs to verify its ability to properly perform methods before introducing them, by ensuring it can achieve the required performance (article 7.2.1.5). Also, if a laboratory carries out a sampling of a material, it needs to have a sampling plan and method established (article 7.3.1). In laboratories dealing with radionuclide content testing, the sampling does not affect the testing results directly, but the sampling procedure has to ensure that the taken and later measured sample adequately represents the tested material. In order to verify the sampling procedure for the needs of radiological tests, a sampling of red mud (13 samples) and bauxite ore (6 samples) was conducted in the aluminum factory “Alumina ltd”, Zvornik, Bosnia and Herzegovina in June 2021. In accordance with the established sampling procedure, GPS coordinate and ambient dose rate were recorded for each sample. Samples were prepared in accordance with IAEA, TRS 295 (1989), placed into identical PVC cylindrical boxes and measured by HPGe gamma spectrometer. Spectra of bauxite and red mud were recorded in 10 consecutive measurements for 21000 s and 6000 s, respectively, in order to achieve good statistic. For the purpose of sampling procedure verification, the counting rates per unit mass in the recorded spectra were compared. For each measurements series, the total counts in the spectrum as well as individual energies mean value and standard deviations were calculated. After the measurements were completed, the average of the each individual series mean values and the associated/corresponding standard deviation were calculated. The measurement result of each individual series is considered satisfactory if, taking into account the calculated standard deviation, it is within +/- two standard deviations of the average of the mean values. The obtained results verified t

Tritium, radioactive isotope of hydrogen, is produced naturally in the upper atmosphere between nitrogen atoms with high energy cosmic rays. Anthropogenic production has disturbed the natural levels of tritium by nuclear atmospheric tests between 1945 and 1963. Tritium is a pure beta emitter with half-life of 12.32 years. Since the main way to eliminate tritium from the atmosphere is through precipitation, whether of natural or artificial origin, tritium easily reaches surface waters and soil from where it can infiltrate into the groundwater and thus enters in the hydrological cycle. Accordingly, knowing the concentration of tritium in precipitation is of essential importance. This paper presents determination of tritium in precipitation collected at Reference Meteorological Station Zeleno Brdo in Belgrade during 2019. Analysis is done in composite monthly samples. Sample preparation involves the first distillation, electrolysis and the second distillation. Samples were measured by Liquid Scintillation Spectrometer Quantulus 1220 after electrolytic enrichment by mixing 8 ml of sample with 12 ml of scintillation cocktail. Tritium activity concentration in analyzed precipitation samples follows normal seasonal variations with maximum in spring-summer months. Based on the monthly amount of precipitation, that is available on the website of the Republic Hydrometeorological Servise of Serbia, it is possible to estimate the deposition of tritium on the earth's surface. The wettest months of 2019 were May and June, and since tritium concentrations are the highest in these months (June: 2.89 Bq/l), the highest value of deposited tritium is obtained in June: 400,8 Bq/m2 . In accordance with the legislation in the Republic of Serbia, the permitted values of tritium are defined only for drinking water (100 Bq/l). An elevated tritium level may indicate the presence of other artificial radionuclides. If an increased activity of tritium is detected, it is necessary to perform an

In accordance with ISO/IC 17025:2017 testing laboratory shall have a procedure for monitoring the validity of results that includes regular participation in interlaboratory comparisons. Interlaboratory comparison RADON2021 was organized in the frame of the bilateral project between Serbia and Montenegro: “Measurement of the radon equilibrium factor in typical residential buildings in Serbia and Montenegro and harmonization of radon measurement techniques” in order to assess congruence of different measurement techniques, and then harmonize methods in case of inconsistencies. Harmonization is of particular importance to neighboring countries, in order to avoid inconsistencies in the classification of radon risk zones along border areas. Thus, six regional laboratories took part in the intercomparison – three from Belgrade and one from Novi Sad, Serbia; one from Podgorica, Montenegro; one from Banja Luka, Bosnia and Herzegovina. All laboratories participated in the indoor radon measurements, while 4 laboratories measured radon in the soil also. The measurement methods and detectors used by the laboratories were: • for air - EPA 402-R-92-004 – Indoor Radon and Radon Decay Product Measurement Devices Protocols, ch. 3.1. with RAD 7, RTM1688-2 and RadonEye; EPA 520/5-87-005 – 1987 EERF Standard Operating Procedures for Rn-222 Measurement Using Charcoal Canisters, ch. 3.4 using adsorption on charcoal canisters; ISO 11665- 4: Measurement of radioactivity in the environment – Air Radon 222: Part 4: Integrated measurement method for determining average activity concentration using passive sampling and delayed analysis with Electretes, and • for soil gas - ISO 11665-11:2016 Measurement of radioactivity in the environment — Air: radon-222 — Part 11: Test method for soil gas with sampling at depth by using active devices RTM1688-2 and RAD 7. The measurements were performed in real conditions where the radon concentration varied following a typical daily variation. Indoor radon c

The aim of the presented research was to investigate the application possibility of wood ash and metakaolin to obtain alkali-activated materials as relatively new materials in the building industry. Thus, in order to assess the adequate use of these waste materials, structural and radiological characteristics should be considered. Until now, the focus has been on ash from thermal power plants produced by burning coal, but a large part of households in our country have individual fireplaces in which wood is used as the basic raw material; thus, it is very interesting to measure the activity concentration of radionuclide in wood ash as well as the possibility of reusing that ash for other purposes. All materials were studied, in terms of physical and chemical characteristics, by methods such as X-ray diffraction (XRD), Fourier transform infra-red (FTIR) spectroscopy, and scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM/EDS). XRD measurements of wood ash samples showed that it consists of calcite and larnite. FTIR spectroscopy revealed a polymeric Si–O–Al framework in alkali-activated materials and Si–O bonding bands corresponding to silicon dioxide. Determination of radionuclide content was performed by means of gamma-ray spectrometry. Results showed that the alkaline activation process led to the decrease in the activity concentration of radionuclides detected in the measured samples. External radiation hazard index (Hex) for wood ash was reduced by more than 50% after alkali activation. The results of activity concentration measurements in alkali-activated materials indicate potential for their safe application in building construction.

Radon flux measurements provide information about how much radon rises from the ground toward the atmosphere, thus, they could serve as good predictors of indoor radon concentrations. Although there are many different mapping methods with many different input data, radon flux data are generally missing and are not included for the delineation of radon priority areas (RPA). The aim of this literature review is to investigate to what extent radon flux was used, or could be used, for the delineation of RPAs. Numerous factors influencing radon flux were identified, but quantifying their contribution to radon flux measurement still remains a challenge. Different methods and measuring devices were used for the determination of radon flux, thus it is necessary to identify possible inconsistencies in order to harmonise different radon flux measurements. Due to the complexity of radon flux measurements, only two countries were identified to have performed national surveys on outdoor radon, which were of much smaller scale compared to those on indoor radon. A positive correlation between radon flux and radon quantities, such as radon in soil gas and indoor radon, indicates that radon flux could be used as an input parameter for the estimation of RPA. By reviewing radon flux models, it was concluded that up-to-date modelled radon flux maps have reached excellent spatial resolution and will be further improved, hence, they could serve as an input for the estimation and delineation of RPA.

The aim of the presented research was to investigate the application possibility of wood ash and metakaolin to obtain alkali-activated materials as relatively new materials in the building industry. Thus, in order to assess the adequate use of these waste materials, structural and radiological characteristics should be considered. Until now, the focus has been on ash from thermal power plants produced by burning coal, but a large part of households in our country have individual fireplaces in which wood is used as the basic raw material; thus, it is very interesting to measure the activity concentration of radionuclide in wood ash as well as the possibility of reusing that ash for other purposes. All materials were studied, in terms of physical and chemical characteristics, by methods such as X-ray diffraction (XRD), Fourier transform infra-red (FTIR) spectroscopy, and scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM/EDS). XRD measurements of wood ash samples showed that it consists of calcite and larnite. FTIR spectroscopy revealed a polymeric Si–O–Al framework in alkali-activated materials and Si–O bonding bands corresponding to silicon dioxide. Determination of radionuclide content was performed by means of gamma-ray spectrometry. Results showed that the alkaline activation process led to the decrease in the activity concentration of radionuclides detected in the measured samples. External radiation hazard index (Hex) for wood ash was reduced by more than 50% after alkali activation. The results of activity concentration measurements in alkali-activated materials indicate potential for their safe application in building construction.

The potential re-use of red mud in the building and construction industry has been the subject of research of many scientists. The presented research is a contribution to the potential solution of this environmental issue through the synthesis of potential construction materials based on red mud. A promising way of recycling these secondary raw materials is the synthesis of alkali-activated binders or alkali activated materials. Alkali-activated materials or inorganic binders based on red mud are a new class of materials obtained by activation of inorganic precursors mainly constituted by silica, alumina and low content of calcium oxide. Since red mud contains radioactive elements like 226Ra and 232Th, this may be a problem for its further utilization. The content of naturally occurring radionuclides in manufactured material products with potential application in the building and construction industry is important from the standpoint of radiation protection. Gamma radiation of the primordial radionuclides, 40K and members of the uranium and thorium series, increases the external gamma dose rate. However, more and more precedence is being given to limiting the radiological dose originating from building materials on the population these days. The aim of this research was to investigate the possible influence of alkali activation-polymerization processes on the natural radioactivity of alkali activated materials synthesized by red mud (BOKSIT a. d. Milići, Zvornik, Bosnia and Herzegovina) and their structural properties. This research confirmed that during the polymerization process the natural radioactivity was reduced, and that the process of alkali activation of raw materials has an influence on natural radioactivity of synthesized materials.

Presented study deals with the final structure and radiological properties of different fly-ash based geopolymers. Lignite fly-ash (lignite Kolubara – Serbia) and wood fly ash were obtained in combustion process together with commercial fly-ash. Synthesis of the geopolymers was conducted by mixing fly-ash, sodium silicate solution, NaOH and water. The samples were strengthened 60 °C for 48 hours after staying at room temperature in covering mold for 24 hours. The X-ray diffraction, Fourier transform infrared and SAM measurements were conducted on the samples after 28 days of geopolymerization process. The X-ray diffraction measurements of lignite fly-ash samples show anhydrite as the main constituent, while wood fly-ash samples consist of calcite, albite and gypsum minerals. Besides determination of physicochemical properties, the aim of this study was radiological characterization of lignite fly-ash, wood fly-ash and the obtained geopolymer products. Activity concentration of 40K and radionuclides from the 238U and 232Th decay series, in ash samples and fly-ash based geopolymers, were determined by means of gamma-ray spectrometry, and the absorbed dose rate, D, and the annual effective dose rate, E, were calculated in accordance with the UNSCEAR 2000 report.

The procedure of radioactive standards preparation by spiking selected matrices with a certified mixture of radionuclides and its validation is presented in this paper. The uncertainty budget of standard total activity was elaborated in details. The experimentally obtained efficiency curves, as well as comparison with the curves obtained by the efficiency transfer, are presented. Additionally, in order to confirm claimed homogeneity of prepared standard bulk materials, the efficiency versus density dependence for the individual gamma ray energies was checked for the same geometries and the results are presented. The results of the participation in recent IAEA PT scheme are discussed also. © 2021 Elsevier Ltd

U ovom radu su predstavljeni rezultati poređenja sadržaja prirodnih radionuklida u različitim uzorcima elektrofilterskog pepela, pepela sa deponija i šljake. Poređenje je izvršeno između rezultata dobijenih u redovnoj kontroli radioaktivnosti u radnoj i životnoj okolini TE „Kostolac“, TE „Kolubara“i TE „Nikola Tesla A“, koje sprovodi Laboratorija za zaštitu od zračenja i zaštitu životne okoline, Instituta za nuklearne nauke “Vinča“. Na osnovu merenja koncentracije prirodnih radionuklida u uzorcima elektrofilterskog pepela, pepela sa deponija i šljake, kao i na osnovu određenog odnosa između dobijenih vrednosti u uzorcima iz različitih termoelektrana, možemo da zaključimo da je ovaj otpadni materijal iz TE “Kostolac” izuzetno povoljan kao sirovina koja bi se koristila za proizvodnju građevinskog materijala i da daje približno dvostruko manji uticaj na gama indeks konačnog proizvoda u odnosu na otpadni material iz drugih termoelektrana., This paper presents the results of the comparison between the naturally occurring radionuclide content in different samples of fly ash, ash and slag. The comparison was conducted between the results obtained within the regular control of radioactivity in working and living environment of TE „Kostolac“, TE „Kolubara“ and TE „Nikola Tesla A“, which is performed by the Radiation and Environmental Protection Department of „Vinča“ Institute of Nuclear Sciences. Based on the activity concentration measurement in samples of fly ash, ash from the ash disposal dumps and slag, as well as based on the calclulated ratio between the values obtained for different coal fired powerplants, it can be concluded that this waste material from TE “Kostolac” is promising material as an additive in building material production and that it gives approximately twice as low contribution to the gamma index as those obtained from other two powerplants.

U radu su prikazani rezultati merenja ukupne alfa i ukupne beta aktivnosti u površinskim vodama, reke Sava, Kolubara i Turija koje se nalaze u okolini termoelektrana Nikola Tesla TENT A i Kolubara za 2018. i 2019. godinu, kao i rezultati ukupne alfa i ukupne beta aktivnosti u Savi i Dunavu u Beogradu, van uticaja termoelektrana. Prikazani su i rezultati merenja ukupne alfa i ukupne beta aktivnosti u drenažnim i prelivnim vodama u termoelektranama Nikola Tesla TENT A i Kolubara za 2018. i 2019. godinu i za termoelektranu Kostolac za 2018. i 2020. godinu. Rezultati analize prikazani u ovom radu su važni s obzirom na to da se stanovništvo u Srbiji dominantno snabdeva vodom iz reka koje se nalaze u okolini termoelektrana., The paper presents the results of gross alpha and gross beta activity measurement in the surface water Sava, Kolubara and Turija in the vicinity of the coal-fired power plants Nikola Tesla TENT A and Kolubara for 2018. and 2019., as well as the results of the gross alpha and beta activity in the Sava and Danube in Belgrade, outside the influence of power plants. The results of measuring the gross alpha and gross beta activity in drain and overflow waters in the power plants Nikola Tesla TENT A and Kolubara for 2018. and 2019. and for the power plant Kostolac for 2018. and 2020. are also presented. Analysis presented in this paper is important considering that the population in Serbia is predominantly supplied with water from rivers located in the vicinity of power plants.

U ovom radu su predstavljeni rezultati merenja jačine ambijentalnog ekvivalenta doze gama zračenja, izvršenih u toku redovnog monitoringa TE „Kostolac“, koje sprovodi Laboratorija za zaštitu od zračenja i zaštitu životne okoline, Instituta za nuklearne nauke “Vinča“. Jačina ambijentalnog ekvivalenta doze je merena u vazduhu na 1m iznad tla na određenim tačkama unutar lokaliteta termoelektrane i na deponijama pepela i šljake, istovremeno sa uzorkovanjem na istim lokacijama, korišćenjem dozimetra sa scintilacionom sondom. Takođe, tokom godina u kojima je vršen monitoring, vršena su i kontinualna merenja ambijentalnog ekvivalenta doze na lokacijama u naseljima u okolini TE „Kostolac“, korišćenjem termoluminescentnih (TLD) dozimetara. Analiziranjem dobijenih vrednosti tokom dužeg perioda kontinualnog i pojedinačnih merenja, dolazi se do zaključka o uticaju rada termoelektrane na životnu i radnu okolinu., This paper presents the results of measurements of the ambient dose equivalent rate of the gamma radiation performed within the regular monitoring of the coal-fired power plant „Kostolac“, performed by the Radiation and Environmental Protection Department of „Vinča“ Institute of Nuclear Sciences. Ambient dose equivalent rate is measured in the air, at 1 m height above the ground at defined sites within the territory of the power plant and the ash and slag disposal dumps, at the moment of sampling at these sites, using a dosimeter with a scintillation probe. Also, during the yearsin which the monitoring was performed, continuous measurements of the ambient dose equivalent on the location of settlements in the vicinity of the power plant were conducted, using termo luminescent dosimeters (TLD). The comparison of the long term measurements and measurements performed on the sampling sites, a conclusion about the influence of power plant on the living and working environment can be reached

U radu su prikazani rezultati određivanja koncentracije proizvedenih radionuklida 90Sr i 137Cs u rečnom sedimentu reke Dunav u Beogradu u 2020. godini. Rezultati su dobijeni u okviru sistematskog ispitivanja nivoa radioaktivnosti u životnoj sredini na teritoriji Beograda. Za analizu sadržaja 90Sr primenjena je radiohemijska metoda, dok je određivanje sadržaja 137Cs urađeno gamaspektrometrijskom analizom. Dobijene vrednosti proizvedenih radionuklida u rečnom sedimentu ne predstavljaju rizik po životnu sredinu, The paper presents the results of activity concentrations of 90Sr and 137Cs in the river sediment of the Danube in Belgrade for 2020. The results were obtained as part of a systematic examination of the radioactivity level in the environment in Belgrade. For determination of 90Sr content, radiochemical method was used, while determination of 137Cs content was done by gamma spectrometric analysis. The obtained values of artificial radionuclides in Danube river sediment do not pose a risk to the environment.

Thermal power plants, as potential pollutants that have a great impact on the environment, have, among other things, the obligation to conduct regular control of radioactivity in the living and working environment. Radionuclides that are naturally present in coal used to produce electricity are concentrated in combustion products (ash, slag, wastewater, etc.). As these products are disposed of in the environment, it is necessary to regularly perform measurements to control the presence of natural radionuclides in samples from the environment near thermal power plants. This paper will present the results of testing the content of natural radionuclides in the soil sampled at several locations in the vicinity of TPP "Nikola Tesla" A and TPP "Kolubara" in the period from 2016-2020 years. The measurements were performed in the Laboratory for Radiation Protection and Environmental Protection of the Vinca Institute of Nuclear Sciences, using the standard gamma spectrometry method after adequate sample preparation. The sampling locations were selected to cover the immediate surroundings of the thermal power plant, where the possible impact of the thermal power plant operation would be most noticeable. Also, sampling was performed at locations that are far from the thermal power plant itself, most often in populated areas, in order to ensure knowledge of the local natural level of radionuclide content in the soil. The measured concentrations of natural radionuclide activity in the soil were monitored over a number of years and a comparison was made between samples taken nearby and those taken away from the thermal power plant, as well as soil samples from other parts of Serbia and literature data. In that way, optimal monitoring of the impact of the thermal power plant operation on the environment is provided., Termoelektrane, kao potencijalni zagaĎivači koji imaju veliki uticaj na životnu okolinu, izmeĎu ostalog imaju i obavezu sprovoĎenja redovne kontrole radioaktivnosti u životnoj i radnoj sredini. Radionuklidi koji su prirodno prisutni u uglju koji se koristi za proizvodnju električne energije, bivaju koncentrisani u produktima sagorevanja (pepeo, šljaka, otpadne vode itd.). Kako se ovi produkti odlažu u životnu sredinu, potrebno je redovno vršiti merenja kojima se kontroliše prisustvo prirodnih radionuklida u uzorcima iz životne okoline u blizini termoelektrana. U ovom radu će biti prikazani rezultati ispitivanja sadržaja prirodnih radionuklida u zemljištu uzorkovanom na više lokacija u okolini TE “Nikola Tesla” A i TE “Kolubara” u periodu od 2016- 2020. godine. Merenja su izvšena u Laboratoriji za zaštitu od zračenja i zaštitu životne srednine Instituta za nuklearne nauke “Vinča”, standardnom metodom gama spektrometrije nakon adekvatne pripreme uzoraka. Lokacije uzorkovanja su odabrane na osnovu Programa kontrole radioaktivnosti, tako da pokrivaju neposrednu okolinu termoelektrana, gde bi eventualni uticaj rada termoelektrane bio najuočljiviji. TakoĎe, uzorkovanje je vršeno i na lokacijama koje su udaljene od same termoelektrane, najčešće u naseljenim mestima, da bi se obezbedilo poznavanje lokalnog prirodnog nivoa sadržaja radionuklida u zemljištu. Izmerene koncentracije aktivnosti prirodnih radionuklida u zemljištu su praćene tokom niza godina i vršeno je poreĎenje izmeĎu uzoraka uzetih u blizini i onih uzetih dalje od termoelektrane, kao i sa uzorcima zemljišta iz drugih krajeva Srbije i podacima iz literature. Na taj način, obezbeĎeno je optimalno praćenje uticaja rada termoelektrane na životnu sredinu

Aerosol sampling and monitoring of naturally occurring and artificial radionuclides is readily performed within the frame of Environmental radioactivity monitoring in the Republic of Serbia. It provides information important for the preservation of the public health and the environment from the harmful effects of ionizing radiation. This type of monitoring has been performed in Institute of Nuclear Sciences Vinča for more than 30 years now. The radionuclides that are measured are: naturally occurring 210Pb, artificial radionuclide 137Cs and cosmogenic radionuclide 7 Be. Particle reactive radionuclides such as 210Pb and 7 Be have been used as atmospheric tracers for studying environmental processes such as cloud scavenging and precipitation [1], aerosol transit and residence times in the troposphere [2], and aerosol deposition velocities [3]. The fission product 137Cs is an indicator of anthropogenic pollution caused by nuclear weapon atmospheric tests and nuclear power plant accidents. Seasonal variation in 137Cs in air is an indicator of the stratosphere-troposphere exchange processes [4]. In most aerosol samples in later years, the activity concentration of 137Cs is below the minimal detectable activity and therefore it was not taken into the consideration in this paper. The activity concentration of 7 Be is dependent on the movements of large air masses and vertical mixing in the atmosphere and also was not discussed in this paper. In this paper, the activity concentration of 210Pb in aerosol samples, obtained over the period from 2014. to 2020., was discussed. Sampling is performed using constant air flow pumps and Whatman filter papers on 6 measuring stations distributed in various parts of the country. Three stations are in urban areas of cities of Belgrade, Vranje and Zaječar and other three are in rural areas (Palić and Zlatibor) or removed from the urban part of the city (Meteorological station in Vinča). The monthly composite sample from each sampling stat

Gamma ray spectrometry with high purity germanium (HPGe) detector is one of the most widely used methods for environmental samples measurements. It is basically a non-destructive method and usually there is no need for the extensive sample preparation. True coincidence summing effect has a significant effect in gamma ray spectrometry analysis, especially in low source-to-detector geometry. Many authors have paid attention to this problem mainly by analyzing and determining coincidence summing correction factors for artificial radionuclides. However, the effect of true coincidence summing can significantly affect the result obtained by gamma ray spectrometry of environmental samples. Therefore, special attention should be paid to the determination of correction factors for coincidence summing of radionuclides from natural series (uranium, thorium and actinium series). Coincidence summing correction factors can be determined in several manners. Application of appropriate software packages is one of the most common. Software packages EFFTRAN and GESPECOR are among the most used ones. These software are based on Monte Carlo simulation. EFFTRAN is efficiency transfer code with semiempirical approach, whereas GESPECOR is dedicated code specifically tailored to solve most of the problems concerning gamma spectrometric measurements. The values of the correction factors depend on the detector geometry as well as the relevant data related to analyzed sample. The geometry of the detector implies the parameters of the detector itself (crystal dimensions, thickness of the dead layer, the thickness of the detector window). On the other hand, the relevant data related to analyzed sample includes dimensions of the container in which the sample is packed, sample density, chemical composition. The aim of this work is to compare coincidence summing factors obtained by using EFFTRAN and GESPEOR software in the case of p-type semiconductor HPGe detector with 30 % relative efficiency. Al

Radon is the radioactive gas originating from the decay chain, mainly uranium and thorium series. The main source of population exposure to ionizing radiation (more than 80 %) is the natural radioactivity. Radon and its short lived progeny contribute with more than 50 % to the radiation dose received by the general population from all sources, and the World Health Organization has recognized radon as the second most important cause of lung cancer. The European Council has laid down a basic safety standards (BSS, Council Directive 2013/59/Euratom) for the protection against the dangers arising from exposure to ionizing radiation, obliging member states, among other, to investigate the exposure of members of the public and workers to indoor radon, to develop a radon action plan and to inform the public about radon levels they are exposed to. As a consequence, this has led to increased number of indoor radon measurements in recent years. There are numerous methods for indoor radon measurement which can be performed either by direct measurement of radon or indirectly by measuring radon progeny, with or without radon presence. The choice of method used depends on the purpose of the measurements, available instrumentation and time. In order to assess the reliability of indoor radon measurement methods available in “Vinca” Institute of Nuclear Sciences, comparative measurement were conducted. Indoor radon concentration was measured in four working rooms in Vinca Institute, two offices and two laboratory premises, in the period of October-November 2020. In all locations continuous radon measurements were performed with tree different active measurement devices: RTM1688-2 and Radon Scout from SARAD GmbH, and RadonEye from RadonFTLAB, while integrated radon measurements were conducted with charcoal canisters. In addition, Equilibrium Equivalent Radon Concentration EERC was measured with radon progeny monitor RPM2200 (SARAD GmbH). Measurement by all active devices was performe

The probabilities of locating peaks with a high relative peak-area uncertainty were determined empirically with nine types of peak-location software used in laboratories engaged in gamma-ray spectrometry measurements. It was found that it is not possible to locate peaks with a probability of 0.95, when they have a relative peak-area uncertainty in excess of 50%. Locating peaks at these relatively high peak-area uncertainties with a probability greater than 0.95 is only possible in the library-driven mode, where the peak positions are supposed a-priori. The deficiencies of the library-driven mode and the possibilities to improve the probabilities of locating peaks are briefly discussed. © 2019 Elsevier Ltd

The second most important source of indoor radon, after soil beneath dwelling, is building material. With the increase in environmental awareness and new energy-saving policies, residents tend to replace the existing windows with tighter windows, which leads to a decrease in air exchange rate and consequently an increase in indoor radon concentration. In case of low exchange rates, dose caused by inhalation of radon and its progeny can exceed external dose originating from the radium content in the surrounding building material. In this paper, surface exhalation rates of radon ( 222 Rn) and thoron ( 220 Rn) from typical building materials used for construction and interior decoration of houses in Serbia were investigated. Surface exhalation rate measurements were performed using the closed-chamber method, while concentrations of radon and thoron in the chamber were continuously measured using an active device, RTM1688-2, produced by SARAD® GmbH. Finally, the impact of the replacement of windows on the indoor radon concentration was estimated.

Open-faced charcoal canisters have been used for radon measurements for over 40 years. This method is sensitive to temperature, changing radon concentrations, humidity and other parameters, but a comprehensive study dealing with the influence quantities and measurement uncertainty was not available in literature. In this paper, all the identified influence quantities are discussed in detail, uncertainty budget is developed, good practice and bad practice examples are introduced and new recommendations are proposed to optimize the method and reduce uncertainty.

Various imported building materials commonly used in construction and industry in Serbia were analyzed using gamma spectrometry. Based on the activity concentrations of 226Ra, 232Th, and 40K in the investigated samples, radium equivalent activity, Raeq, absorbed dose rate, D, annual effective dose, DE, and the external hazard index, Hex, were calculated to assess the radiation hazard for people. The Raeq for most of the analyzed samples (416 in total) was lower than the maximum admissible value of 370 Bqkg-1 set in the UNSCEAR report. The absorbed gamma dose rate in air was found to vary from 0.030 mGyh-1 to 1.328 mGyh-1 which in some cases exceeded indoor dose rates in Europe. The obtained values for annual effective dose exceed the limits of 0.41 mSv given in literature for about 5 % of measured samples, while values of Hex were higher than unity for three samples of cement, eight samples of granite, and one sand sample. As a possible source of elevated effective dose, the radon exhalation from building materials was estimated using the parameters given in literature. The internal dose due to 222Rn exhaled from the building material was found to be up to nine times higher than external dose due to 226Ra content in some cases.

An internal consistency test of the calculation of coincidence-summing correction factors FC for volume sources is presented. The test is based on exact equations relating the values of FC calculated for three ideal measurement configurations. The test is applied to a number of 33 sets of FC values sent by 21 teams. Most sets passed the test, but not the results obtained using the quasi-point source approximation; in the latter case the test qualitatively indicated the magnitude of the bias of FC. © 2019 Elsevier Ltd