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This study deals with the design of the checkpoint system for monitoring the environmental radioactivity in the vicinity of the nuclear reactors. As the design site was selected the Vinča Institute of Nuclear Sciences in the capital city of the Republic of Serbia. There are situated two former nuclear research reactors with potential hazardous materials in controlled conditions. Due to the high risk of ecosystem contamination in the vicinity of various nuclear facilities such as reactor, radiological analyses of coastal soils, sediments and stream/river water were performed at the selected checkpoints. The investigation included determination of gross alpha and gross beta activities, gamma spectrometric analysis and analysis of 90Sr content in the collected environmental samples, as well as determination of 3H activity concentration, but only in water samples. Gross alpha activity ranged from 0.013 Bq/L to 0.057 Bq/L for water samples, from 130 Bq/kg to 280 Bq/kg for soil samples, and from 120 Bq/kg to 270 Bq/kg for sediment samples. Gross beta activity ranged from 0.128 Bq/L to 0.332 Bq/L for water samples, from 850 Bq/kg to 1600 Bq/kg for soil samples, and from 660 Bq/kg to 1200 Bq/kg for sediment samples. The main contribution to gamma radiation in water samples was made by 40K and 137Cs. The 226Ra/238U ratio ranged from 0.37 to 1.24 in soil and from 0.51 to 1.16 in sediment. 90Sr and 3H were detected in all studied samples. The presented results and the increased radiation risk in the above mentioned area show that the surrounding of the nuclear reactors and the exposure of the population to ionizing radiation must be constantly monitored.

The main goal of this study was the evaluation of physical–chemical, as well as radiological properties of residual materials used for synthesis of alkali activated materials (AAMs) for the possible application as new materials in a civil engineering industry. Also, the purpose of this research was to investigate the hydrophobicity of new alumino-silicate materials and the influence of Si/Al ratio on their surface properties. Contact angle measurement (CAM) as reliable indicator of hydrophobicity was determined for synthesized AAMs using water and ethylene glycol as reference liquids. Alkali-activated materials were synthesized from various precursors: kaolin, bentonite and diatomite. Characterization of phase structure and microstructure was performed by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Scanning electron microscopy and Energy-dispersive X-ray (SEM/EDX) spectroscopy. Contact angle measurements confirmed that the alkali-activated materials synthesized from metakaolin are the most porous, which can be explained by the smallest Si/Al ratio. The maximum value of contact angle and free surface energy (110.2 mJ/m2 ) has been achieved for alkali-activated materials synthesized by diatomite (GPMD). Concentration of 40K and radionuclides from the 238U and 232Th decay series in waste precursors, their metaphases and AAM samples synthetized by alkali activation were determined together with corresponding absorbed dose rate (D˙) and the annual effective dose rate. Natural activity concentrations in the alkali-activated materials were found to be lower than that of both residual materials and calcined ones.

MetroPOEM (Metrology for harmonization of measuremenets of environmental pollutant in Europe) je trogodišnji evropski projekat finansiran u okviru EMPIR programa.Globalna težnja ka što manjem zagadjenju (European Green Deal´s ambition for zero pollution) zahteva razvoj visoko osetljivih tehnika kojima se mogu detektovati niske koncentracije polutanata. Masena spekrometrija je najznačajnija tehnika za odredjivanje neradioaktivnih, ali i dugoživućih radioaktivnih polutanata. Glavni cilj ovog projekta je da uspostavi vezu izmedju radiometrijskih i masenih tehnika merenja polutanata. Takođe, cilj projekta je i smanjenje mernih nesigurnosti, limita detekcije, ali i razvoj novih referentnih materijala kojima bi se obezbedila sledivost mernih procedura., The MetroPOEM project (Metrology for harmonization of measurements of environmental pollutants in Europe) is a three-year European project financed under the EMPIR program. The global aspiration towards as little pollution as possible (European Green Deal's ambition for zero pollution) requires the development of highly sensitive techniques that can detect low concentrations of pollutants. Mass spectrometry is the most important technique for determining non-radioactive, but also long-lived radioactive pollutants. The main goal of this project is to establish a link between radiometric and mass pollutant measurement techniques. Also, the goal of the project is the reduction of measurement uncertainties, detection limits, but also the development of new reference materials that would ensure the traceability of measurement procedures.

Ugalj kao fosilno gorivo sadrži brojne prirodne radioaktivne izotope koji pripadaju uranovom i torijumovom nizu, kao i 40K. Najviše se koristi u industriji, kao i u proizvodnji energije. Problem u vezi sa proizvodnjom energije iz uglja je takozvani „energetski otpad“, kao što su pepeo i šljaka, koji predstavljaju nesagorivi i nesagoreli ostatak pri sagorevanja uglja. Ako se pepeo i šljaka odlažu u životnu sredinu, može doći do povećanja i/ili preraspodele prirodnog sadržaja radionuklida. Da bi se utvrdio potencijalni uticaj „energetskog otpada“ na životnu sredinu, uzorci uglja, pepela i šljake iz termoelektrana „Nikola Tesla“ i „Kolubara“ mereni su poluprovodničkim HPGe spektrometrom u Laboratoriji za nuklearnu i plazmu fiziku Instituta „Vinča“. Kao rezultat ovih merenja, dobijene su koncentracije prirodnih radionuklida i veštačkog radionuklida 137Cs kao, što je prikazano u ranije objavljenim radovima. Prikazani rezultati su u saglasnosti sa istraživanjima sprovedenim širom sveta. Da bi se obezbedila tačnost i preciznost (pouzdanost) dobijenih rezultata merenja, u okviru Laboratorije uspostavljen je program kontrole kvaliteta (QC) i osiguranja kvaliteta (QA). Interna kontrola obuhvata proveru karakteristika poluprovodničkog HPGe spektrometra koji se koristi za merenje svih analiziranih uzoraka. Tačkasti izvori 60Co i 137Cs se koriste kao kontrolni izvori za proveru položaja pika, ukupne površine ispod pika, FWHM (puna širina na polovini maksimuma pika), FWTM (puna širina na desetini maksimuma pika) i odnos FWHM/FWTM. Pored navedenih karakteristika, redovno se kontroliše i ukupni odbroj prirodnog fona. Svaka od navedenih karakteristika može ukazati na neku nepravilnost u radu detektorskog sistema. Cilj ovograda je da se prikažu kontrolne karte ispitivanih karakteristika poluprovodničkog HPGe spektrometra korišćenog za merenje uzoraka uglja, pepela i šljake. Dobijene kontrolne karte predstavljaju važan alat na osnovu kojeg se analizira dugoročna stabilnost spektrome, eir daughter products, as well as 40K. It is widely used in industry as well as in energy pro-duction. The problems associated with the production of energy from coal is the so-called “energy waste”, such as ash and slag, which are incombustible and unburnt residue from combustion of coal. If ash and slag are released into the environment an increase and/or redistribution of natural radio-nuclide content can occur. To determine the potential impact of “energy waste” on the environment, samples of coal, ash, and slag from thermal power plant "Nikola Tesla" and "Kolubara" were meas-ured with a semiconductor HPGe spectrometer. Results of activity concentration of natural radionu-clides and artificial 137Cs in coal, slag and ash are presented in few previously published papers and obtained values are in accordance with similar worldwide investigations. o ensure the accuracy and precision (reliability) ofthe obtained measurement results, quality control (QC) and quality assurance (QA) program were established. Internal control includes check-ing of the characteristics of HPGe spectrometer used for measurement of all analysed samples. Point sources of 60Co and 137Cs are used as control sources for checking following characteristics: peak positions, net peak area, FWHMs (Full Width at Half Maximum), FWTMs (Full Width at Tenth Max-imum) and FWHM/FWTM ratios. In addition to the mentioned characteristics, the counting of back-ground is also regularly controlled. Each of the mentioned characteristics may indicate some irreg-ularity in the operation of the detector system and thus could influence reliability of performed activ-ity concentration measurements.The paper presents the control charts of the examined characteristics of the HPGe spectrometer used for measurements of coal, ash and slag samples. The obtained control charts indicate the long-term stability of the spectrometer and hence confirm accuracy and precision of measurement results.

In this work, the thermal decomposition process of coal bottom ash (collected after lignite combustion in coal-fired power plant “Kostolac B” (TEKO-B), Serbia) was investigated, using simultaneous TG (thermogravimetry) – DTG (derivative thermogravimetry) techniques in an inert (Ar) atmosphere, at various heating rates (10.3, 20.9 and 32.1 K/min). In addition to thermal characterization of the sample, the chemical composition and naturally occurred radionuclides were also determined. Using the model-free (isoconversional) (by Friedman (FR), Kissinger-Akahira-Sunose (KAS), Ozawa-Flynn-Wall (OFW) and Vyazovkin (VY) methods) analysis, the complex kinetic nature of the process was successfully resolved. The conducted numerical optimization of the process (using non-linear least square optimization) had confirmed accuracy and reliability of estimated kinetic parameters. Model-based (model-fitting) kinetic analysis showed the existence of a complex reaction scheme, over two consecutive reactions steps and one single-stage reaction step, via mechanism order An, F2, Fn, R3, Cnm (through n-dimensional nucleation/growth, chemical reactions, and n-th order and m-power with autocatalysis mechanisms). Through physicochemical interpretation of mechanism scheme, an assessment of recovery of valuable metals and metal oxides was performed, by analysing the concentration of reaction species in a function of temperature of individual steps. Likewise, the influence of certain precursor involved in decomposition process as catalyst (in order to increase the yield of targeted product) was also inspected. Finally, the simulation of actual process using the results obtained from applied methods/models was performed, through application of modulated dynamic (MD) prediction.

Determination of specific activity concentration of radioisotopes in environmental samples can be used to assess the long-term kinetics of the decline of radioisotopes. Based on the obtained activity concentrations of tritium in the Danube, the effective ecological half-life is estimated. Assuming that the Danube in Belgrade is not affected by nuclear power plants, even though it is positioned downstream of the Paks Nuclear Power Plant in Hungary, a slow decline of tritium was observed. The effective ecological half-life of tritium was also determined after correction by subtracting its components originating from cosmic radiation and the atmospheric transfer from nuclear facilities worldwide.

This paper presents the results for gross alpha and gross beta activity in leaves samples: Fig (Ficus carica), Vine (Vitis vinifera L.), and Apricot (Prunus armeniaca). Samples were collected in Iraq (Sulaymaniyah, Kurdistan region), and in the Serbia (Belgrade), in the summer 2018. The analysis was done in dried and milled samples as well as in the annealed samples, using gas flow proportional counter. Determination of gross alpha and gross beta activity presents rapid method, essential for the analysis of radioactivity in environmental samples. The gross alpha activity is defines as the total activity of alpha emitters, and originates from the decay chains of 238U and 232Th, which quantity depends on the geological and geographical formation of natural radionuclides. The main contributor to the gross beta activity is natural long-lived isotope 40K, as well as 210Pb, 228Ra. The gross beta measurements also include a contribution from anthropogenic radionuclides 137Cs and 90Sr. Radionuclides that emitting low-energy beta radiation (3 H and gaseous or volatile radionuclide such as iodine) cannot be detected by gross beta activity measurements.

This paper presents distribution and seasonal variations of tritium, radioactive isotope of hydrogen, in Sava River in Belgrade. Tritium besides its natural origin also has an artificial origin, through human activity including the operation of nuclear power plants, nuclear weapons manufacturing and atomic bomb tests. Knowing the concentration of tritium in the Sava River in Belgrade is important because it is located downstream from the Krško Nuclear Power Plant in Slovenia. Analysis of tritium concentrations in surface water samples were done in composite monthly samples during 2017-2022. Tritium activity was determined by liquid scintillation spectrometer using electrolytic enrichment. Seasonal variations were estimated by determination of average monthly concentrations and seasonal indices.

Measurement of radon (222Rn) concentration using charcoal filters according to the EPA 520/5-87-005 method is performed in Radiation and Environment Protection Department of Vinča Institute for Nuclear Sciences on NaI scintillation detectors. Concentration of radon adsorbed on active charcoal is determined indirectly, by gamma spectrometry of its daughter products via their gamma peaks at 295 keV, 352 keV (214Pb) and 609 keV (214Bi). In order to assure the reliability of the measurement results, and in accordance with Standard ISO 17025/17 quality control and quality assurance (QA/QC) procedures needs to be applied. Related activities ought to be planned, described in the quality control documentation, performed in a systematic manner, recorded and reviewed. First, the energy and efficiency calibration of the detection system needs to be performed in a proper manner. The NaI scintillation spectrometer is internally calibrated using the certified radioactive 226Ra standard in charcoal matrix and in the geometry identical to the measurement geometry, produced by Czech Metrology Institute and traceable to Bureau International des Poids et Mesures (BIPM). As defined in laboratory’s procedures a regular quality control of the NaI scintillation detector is performed once a week. Quality control activities include the background measurement and measurement of adequate reference material. Gross background count rate in the energy region of interest is used to verify that the detector and shield have not been contaminated and that there is no significant variation of the background. Reference material used is the soil sample with known content of 226Ra. Gross count rate in the reference material spectrum is used to check the energy and efficiency calibration. These values are recorded and verified if they are within the acceptance limits. Obtained results, together with acceptance limits, for a certain period (one year usually) is graphically presented in the control charts.

As a part of regular activities of the accredited laboratory, the Laboratory for Radiation Measurements of the Radiation and Environmental Protection Department, Institute Vinča, every year takes part in the proficiency tests organized by IAEA. This year, within the framework of IAEA – TERC – 2022 – 01/02 Proficiency Test, one of the requests was to measure the simulated surface contamination using the instrument that are at the disposal in the participant laboratories. The results should be reported in the units of counts/s/cm2 in order to be comparable. In this paper, the measurement method and subsequent specific calculations for the simulated surface contamination are explained and the results of the proficiency test stated and discussed.

U radu je prikazana procena stanja u životnoj sredini Mokre Gore, posmatrano sa radioekološkog aspekta. Rezultati gamaspektrometrijskih merenja sprovedenih na germanijumskom detektoru visoke čistoće su pokazala prisustvo 226Ra, 232Th i 40K u zemljištu Mokre Gore u koncentracijama aktivnosti: od 10 Bq/kg do 20 Bq/kg za 226Ra, 13 Bq/kg do 34 Bq/kg za 232Th i 96 Bq/kg do 250 Bq/kg za 40K. Na osnovu rezultata gamaspektrometrijskog merenja aktivnosti navedenih primordijalnih radionuklida, izvršena je procena radijacionog rizika usled terestričkog izlaganja stanovništva na području Mokre Gore. Proračunom su procenjeni sledeći parametri radijacionog rizika: ukupna jačina doze gama zračenja (srednja vrednost 28,6 nGy/h), godišnja efektivna doza (srednja vrednost 0,035 mSv) i indeks radijacionog rizika usled spoljašnjeg izlaganja (srednja vrednost 0,169). Procenjene vrednosti navedenih parametara ukazuju na to da ne postoji uvećan radijacioni rizik za stanovništvo ispitanog područja usled terestričkog izlaganja.

Gasni proporcionalni brojač koristi se za određivanje ukupne alfa i ukupne beta aktivnosti u različitim matriksima kao i za određivanje aktivnosti antropogenog radionuklida 90Sr koji je čist beta emiter. Ovaj rad predstavlja pregled kontrole kvaliteta gasnog proporcionalnog brojača Thermo-Eberline FHT 770T i određivanja efikasnosti, koja se sprovodi sa sertifikovanim standardima 241Am i 90Sr. Brojač ima mogućnost simultanog merenja na 6 detektora i određivanja aktivnosti reda mBq. U radu su prikazani i rezultati sprovedene eksterne kontrole kvaliteta učešćem u interkomparativnom merenju 90Sr, ukupne alfa i ukupne beta aktivnosti u uzorcima vode, organizovanom od strane Međunarodne Agencije za Atomsku Energiju tokom 2022. godine.

Mjerenja koncentracije aktivnosti radionuklida Be-7 (berilij-7), Pb-210 (olovo 210) i Cs-137 (cezij-137) u Zemljinoj atmosferi neophodna su za razumijevanje atmosferskih procesa, kvalitete zraka i radioaktivnosti okoliša. Berilij-7 je radioaktivni izotop koji prvenstveno nastaje interakcijom kozmičkih zraka s atomima dušika i kisika u gornjoj atmosferi. Njegov kratki poluživot čini ga vrijednim tragačem za atmosferske procese u relativno kratkim vremenskim razdobljima. Olovo-210 je radioaktivni izotop čiji je primarni izvor u atmosferi raspad plina radona. S dužim poluživotom od Be-7, pogodan je za proučavanje dugotrajnijih atmosferskih procesa. Cezij-137 je, s druge strane, antropogeni radioizotop s vremenom poluraspada čak i dužim od onog Pb-210, što ga čini dobrim dugoročnim ekološkim tragačem. Nedavno je uspostavljena baza podataka za praćenje radioaktivnosti tla u zraku (GRAMON). Sadrži rezultate mjerenja radioaktivnosti u površinskom zraku na sedam lokacija: Beograd (Srbija), Ljubljana i Krško (Slovenija), Sarajevo (Bosna i Hercegovina), Podgorica (Crna Gora), Skopje i Bitola (Sjeverna Makedonija). Naš rad daje statističku analizu mjesečnih (prosječnih) vrijednosti koncentracija aktivnosti radionuklida za svaku lokaciju od 2010. do 2019. Rezultati pokazuju prostorne razlike i vremensku evoluciju radioaktivnosti zraka u ovoj regiji koja je obično nedovoljno zastupljena u velikim studijama., Measurements of activity concentrations of radionuclides Be-7 (beryllium-7), Pb210 (lead210), and Cs-137 (cesium-137) in the Earth’s atmosphere are essential for understanding atmospheric processes, air quality, and environmental radioactivity. Beryllium-7 is a radioactive isotope produced primarily by cosmic ray interactions with nitrogen and oxygen atoms in the upper atmosphere. Its short half-life makes it a valuable tracer for atmospheric processes on relatively short timescales. Lead210 is a radioactive isotope whose primary source in the atmosphere is decay of radon gas. With a longer half-life than Be-7, it is suitable for studying longerterm atmospheric processes. Cesium-137, on the other hand, is an anthropogenic radioisotope with a half-life even longer than that of Pb-210, which makes it a good long-term environmental tracer. The Ground Air Radioactivity Monitoring (GRAMON) database has been recently established. It contains the outcomes of radioactivity measurements in the surface air at seven locations: Belgrade (Serbia), Ljubljana and Krško (Slovenia), Sarajevo (Bosnia and Herzegovina), Podgorica (Montenegro), Skopje and Bitola (North Macedonia). Our paper gives a statistical analysis of monthly (average) values of the radionuclides’ activity concentrations for each location from 2010 to 2019. The results demonstrate spatial differences and temporal evolution of air radioactivity over this region commonly underrepresented in large-scale studies.

U ovom istraživanju analizirana je fraktalna priroda vremenske serije specifične aktivnosti berilijuma-7 u površinskom sloju atmosfere u Beogradu, Srbija, sa ciljem da se prouči dinamika njene samosličnosti, a s posebnim fokusom na godišnji ciklus. Korišćene su metode vejvlet analize i vremenski zavisne detrendovane pokretne srednje vrednosti radi identifikacije karakterističnih intervala i procene Hurstovih eksponenata. Podaci o specifičnoj aktivnosti berilijuma-7 preuzeti su iz GRAMON baze podataka, za lokaciju Beograd (44,88 °N; 20,58 °E; 95 m nadmorske visine). Vremenska serija obuhvata 362 mesečna merenja od 1991. do 2022. godine. Rezultati ukazuju na postojanje izraženog godišnjeg ciklusa u ovoj vremenskoj seriji. Takođe, promene u lokalnom Hurstovom eksponentu otkrivaju varijacije u ponašanju vremenske serije – ona iz umereno korelisanog prelazi u izrazito antikorelisan proces između 2015. i 2020. godine. Ovaj rezultat biće predmet šire analize koja uključuje i druge lokacije iz GRAMON baze podataka.

U radu je razmatran potencijalni odnos između dobijenih rezultata za koncentraciju tricijuma u kišnici i rekama, Savi i Dunavu, u Beogradu. Uzorkovanja su vršena svakog meseca tokom 2021. godine. Svi uzorci su koncentrisani primenom metode sa elektrolitičkim obogaćenjem, dok je za detekciju tricijuma korišćen tečni scintilacioni spektrometar. Dobijeni rezultati korišćeni su za izračunavanje količine tricijuma deponovane po m2 površine, kao i prosečnog toka tricijuma u rekama na osnovu protoka vode. Dobijena distribucija tricijuma tumačena je u skladu sa meteorološkim i hidrološkim parametrima., The potential relationship between the obtained results for the tritium concentration in precipitation and in the Sava and Danube River in Belgrade was analyzed. Sampling was done during 2021. All samples were concentrated using the method with electrolytic enrichment, while a liquid scintillation spectrometer was used for tritium detection. The obtained results were used to calculate the amount of tritium deposited per m2 of surface as well as to estimate the average flow of tritium in rivers based on river water flow. The obtained distribution of tritium was interpreted in accordance with meteorological and hydrological parameters.

Sprovedeno istraživanje je usmereno na analizu trenda promene ukupne alfa i ukupne beta aktivnosti u poljoprivrednom zemljištu i usevima višegodišnjeg oglednog polja. Analiza je urađena primenom akreditovane metode za određivanje ukupne alfa i ukupne beta aktivnosti u čvrstim matriksima. Merenja su obavljena u Laboratoriji za zaštitu od zračenja i zaštitu životne sredine Instituta za nuklearne nauke “Vinča” na niskofonskom gasnom proporcionalnom brojaču Thermo Eberline FHT 770T. Izmerene vrednosti ukupne alfa aktivnosti variraju od 158 Bq/kg do 324 Bq/kg i ukupne beta aktivnosti od 600 Bq/kg do 1324 Bq/kg za uzorke zemljišta. Za uzorke biljnih kultura vrednosti ukupne alfa aktivnosti su u intervalu od 5 Bq/kg do 167 Bq/kg suve materije, dok su vrednosti ukupne beta aktivnosti u intervalu od 180 Bq/kg do 584 Bq/kg suve materije. Rezultati istraživanja su značajni, jer daju osnovne radiološke informacije od vitalnog značaja za ispitivano područje. Ovo je prvi pokušaj generisanja osnovnih podataka o radijacionom opterećenju zemljišta i biljnih kultura poljoprivrednog ekosistema alfa i beta emiterima, koji su određeni skrining metodom za monitoring životnog okruženja., The conducted research is focused on the analysis of the trend of changes in gross alpha and gross beta activity in agricultural soil and crops of perennial experimental fields. The analysis was performed using an accredited method for determining gross alpha and gross beta activity in solid matrix. The measurements were performed in the Radiation and Environmental Protection Department in Vinča Institute of nuclear Sciences on a low-level gas proportional counter Thermo Eberline FHT 770T. The measured values of gross alpha activity varied from 158 Bq/kg to 324 Bq/kg, and from 600 Bq/kg to 1324 Bq/kg for the gross beta activity in soil samples. For plant samples, values ranged from 5 Bq/kg to 167 Bq/kg of dry matter, and from 180 Bq/kg to 584 Bq/kg of dry matter for gross alpha and gross beta activity, respectively. The results of the research are significant, because they provide basic radiological information of vital importance for the investigated area. This is the first attempt to generate data base on the radiation load of soil and crops of the agricultural ecosystem with alpha and beta emitters, which were determined by the screening method for environmental monitoring.

Kontrola kvaliteta laboratorijskog procesa zauzima značajno mesto u svakodnevnom laboratorijskom radu. Obzirom na važnost, međunarodni standardi su propisali načine i zahteve za vršenje ovakve kontrole. Jedan od zahteva standarda ISO 17025 je obezbeđenje poverenja u rezultate merenja, koje se, između ostalog, može vršiti kontinuiranim praćenjem parametara karakterističnih za laboratorijsku metodu od interesa preko konstruisanja tzv. kontrolnih karti. U radu su prikazani rezultati troipogodišnje analize rada gamaspektrometrijskog sistema u Laboratoriji za nuklearnu i plazma fiziku INN „Vinča“. Merenja su vršena jednom nedeljno a kao kontrolni izvori korišćeni su tačkasti izvori Co-60 i Cs-137. Pored praćenja odbroja ispod pika, položaja pika, širine na polovini visine pika (FWHM), širine na desetini visine pika (FWTM), kao i njihovog međusobnog odnosa (FWTM/FWHM), praćen je i odbroj u fonu. Rezultati su pokazali da gamaspektrometrijski sistem ima zadovoljavajuću stabilnost u radu u dužem vremenskom periodu., Quality control of the laboratory process plays an important role in daily laboratory work. Due to its importance, international standards have issued the ways and requirements for performing such a task. One of the requirements of the ISO 17025 standard is to ensure confidence in the measurement results, which, among other things, can be done by continuously monitoring the parameters characteristic of the laboratory method of interest through the construction of the so-called control charts. The paper presents the results of a three-and-a-half-year analysis of the gamma spectrometric system measurements in the Laboratory for Nuclear and Plasma Physics of the INN "Vinča". Measurements were made once a week and point sources Co-60 and Cs-137 were used as control sources. In addition to monitoring the count below the peak, the position of the peak, the full width at half maximum (FWHM), the full width at tenth maximum (FWTM), as well as their mutual ratio (FWTM/FWHM), the count in the background was also monitored. The results show that the gamma spectrometric system has satisfactory stability over a long period of time.

Oko pola efektivne doze koju stanovništvo primi usled izlaganja jonizujućem zračenju potiče od radona i njegovih potomaka, te je problematika radona važna u oblasti zaštite od zračenja. Takođe, kao hemijski inertan gas, radon je našao primenu u izučavanju životne sredine kao traser za razne geološke i atmosferske procese. Jedna od važnih primena radona je u problematici praćenja gasova koji izazivaju efekat staklene bašte (greenhouse gases – GHG). Pokazano je da se poznavanjem fluksa radona iz zemlje i priraštaja koncentracije radona i koncentracije GHG u istom vremenskom intervalu tokom noći može odrediti fluks GHG. U ovom radu će biti prikazani odabrani rezultati nedavno završenog traceRadon projekta čiji je cilj bio razvijanje metrološki sledivih metoda merenja niskih koncentracija radona u atmosferi u granicama od 1 Bq m-3 do 100 Bq m-3, kao i unapređenje tehnika merenja i samo merenje radonskog fluksa, što će doprineti ispitivanju klimatskih promena kroz obezbeđivanje pouzdane procene fluksa GHG. Takođe, u sklopu projekta, vršila se procena do koje mere se radon u spoljašnjoj sredini i radonski fluks mogu koristiti za procenu radonskih prioritetnih oblasti., Since more than a half of the effective doses from all ionising radiation come from the exposure to radon and its progeny, radon is important in the field of radiation protection. Being a noble gas and therefore chemically inert, radon is also used as a tracer for different geological and atmospheric processes. Radon is of interest to climate scientists for monitoring greenhouse gasses (GHG). It is known that by knowing radon flux and variation of radon and GHG concentration at the same period of time during the night, it is possible to estimate emission of GHG. In this paper, the most important results of recently finished EMPIR project 19ENV01 traceRadon “Radon metrology for use in climate change observation and radiation protection at the environmental level” are presented. Project aimed to develop the capability to measure SI traceable radon activity in the range of 1 Bq m-3 to 100 Bq m-3, suitable for outdoor radon measurements, to develop the capability for traceable radon flux measurements in the field which is important for GHG emission estimates and validation of contemporary radon flux models. Within the project it was investigated to what extent radon flux and outdoor radon data could be used for estimation of radon priority areas.

Rutinska merenja uzoraka iz životne sredine gama spektrometrijom zahtevaju pripremu radioaktivnih standarda različitih matriksa. Radioaktivni standardi se koriste u svim fazama procesa merenja, uključujući validaciju metoda, kalibraciju i kontrolu kvaliteta. U Laboratoriji za Zaštitu od zračenja i zaštitu životne sredine, Instituta za nuklearne nauke „Vinča” radioaktivni standardi se pripremaju korišćenjem sertifikovanog radioaktivnog rastvora različitih radionuklida. U ovom radu je opisan postupak pripreme radioaktivnih standarda koji obuhvata izbor matriksa, pripremu i spajkovanje pripremljenih matriksa sa sertifikovanim radioaktivnim rastvorom, proveru homogenosti, pakovanje standarda u odgovarajuću geometriju i njihova merenja u kontakt geometriji na gama spektrometru. Za sve materijale matriksa pripremljeni su i uzorci „blenka“ i mereni u istoj geometriji kao i kalibracioni standardi. Nakon analize snimljenih spektara, fitovanjem datih tačaka efikasnosti dobijene su kalibracione krive. U ovom radu dat je i opis budžeta merne nesigurnosti za aktivnosti radionuklida prisutnih u pripremljenim standardima., The routine measurements of environmental samples using gamma-ray spectrometry indicate the needs for preparing radioactive standards for various matrices. The radioactive standards are used in all phases of the measurement process, including method validation, calibration and quality control. In the Radiation and Environmental Protection Departmen in the "Vinča" Institute of Nuclear Sciences, radioactive standards are prepared using a certified radioactive solution of mixed radionuclides. The procedure for radioactive standards preparation, which includes matrix selection and preparation, spiking with a certified radioactive solution, homogeneity check, matrix packing in the appropriate geometry and measurement of the prepared standards using a gamma spectrometer, is described in this paper. For all matrix materials, "blank" samples were prepared in the same manner as the standard materials and measured in the same geometry as the calibration samples. After the analysis of recorded spectra and evaluation of the obtained data for efficiency at given energies, calibration curves were obtained by fitting. The uncertainty budget of the activity for all radionuclides present in the prepared standards is also defined in this paper.

Radon is the main source of natural radiation and has been classified as a carcinogen by the relevant international organizations. It is released from soil, water, building materials in the atmosphere and the most significant part of dose due to radon is received by the inhalation of 222Rn and its progeny in closed spaces. At Technical College of Applied Sciences in Zrenjanin (TCAS) two-day long radon concentration measurements were performed in eight rooms during summer holidays by using open charcoal canisters (EPA520 method) and by simultaneously engaged active type Airthings radon detectors. During the measurements open charcoal canisters and Airthing detector were placed one near the other at the table of about 1 m height, windows and doors in the rooms were kept closed and rooms were also not ventilated for some time before the start of the measurements. These studies were performed in order to check radon concentration levels at TCAS as part of the project Radon Level Measurement activities financed by the Provincial Secretariat for Higher Education and Scientific Research. The results were compared and discussed.

Problem u korišćenju stručne terminologije je u poslednje vreme sve izraženiji. Jedan od uzroka za takvo stanje leži u činjenici da je engleski jezik ušao u svakodnevnu upotrebu. Pored toga, činjenica da se srpski standardi objavljuju na engleskom jeziku preuzimanjem međunarodnog ili evropskog standarda još više doprinosi produbljivanju ovog problema. Korišćenje različitih termina za isti pojam može se razrešiti uvođenjem Rečnika stručnih termina. U radu su diskutovane opcije za nekoliko često korišćenih termina., The issue of using professional terminology has been more apparent in recent times. One of the reasons for such occurrence is the fact that English language has been widely used on regular basis. In addition, the fact that the Serbian standards have been adopted in English language additionally contributes to deepening this issue. The use of varying terms for the same notion can be overcome by introducing the Dictionary of Professional Terminology. This paper looks into the options for several frequently used terms.

Improperly storage of fly ash as industrial wastes has been a cause of land contamination issues. These wastes or by-products have the potential to be used as secondary raw materials in construction, promoting the concept of a circular economy that will avoid land contamination. Here we evaluate radiological environmental impacts when wastes that contain elevated levels of naturally occurring radionuclides (NORs) such as fly ash and wood ash are made into 'green cements' such as geopolymers or alkali-activated materials (AAMs). Alkali-activated materials were formed by alkali-activation reaction of wood and fly ash, as a solid precours, and alkali activator solution, sodium hydroxide and sodium silicate. Three differente concentration of alkali solution were used. Determination of radionuclide content was performed by means of gamma-ray spectrometry. The external absorbed gamma dose rate was 68.6-98.1 nGy/h, and external radiation hazard index for alkali-activated material AAM4, AAM6 and AAM12 were 0.544 Bq/kg, 0.575 Bq/kg and 0.403 Bq/kg, respectively. The results of activity concentration measurements in alkali-activated materials indicate potential of their safe application in building constructions. In terms of some the structural characterizations the obtained alkali activated materials were examined., Nepravilno skladištenje letećeg pepela kao industrijskog otpada je uzrok problema kontaminacije zemljišta. Ovaj otpad ili nusproizvodi imaju potencijal da se koriste kao sekundarne sirovine u građevinarstvu, promovišući koncept kružne ekonomije kako bi se izbegla kontaminaciju zemljišta. U ovom radu procenjuje se radiološki uticaj na životnu sredinu kada se otpad koji sadrži povišene nivoe prirodnih radionuklida kao što su leteći pepeo i drveni pepeo pretvara u zelene cemente kao što su geopolimeri ili alkalno aktivirani materijali (AAM). Alkalno-aktivirani materijali nastali su reakcijom alkalne aktivacije drvenog i elektrofilterskog pepela, kao čvrstih prekursora, i rastvora alkalnog aktivatora, natrijum hidroksida i natrijum silikata. Korišćene su tri različite koncentracije ratvora alkalnog aktivatora. Određivanje sadržaja radionuklida urađeno je spektrometrijom gama zraka. Jačina apsorbovane doze bila je 68,6-98,1 nGy/h, a Hex (Bq/kg ) za alkalno aktivirane materijale AAM4, AAM6 i AAM12 je bio 0,544 Bq/kg, 0,575 Bq/kg i 0,403 Bq/kg, respektivno. Rezultati merenja koncentracije aktivnosti u alkalno aktiviranim materijalima ukazuju na potencijal njihove bezbedne primene u građevinskim konstrukcijama. Alkalno aktivirani materijali su ispitani i u pogledu nekih strukturnih karakteristika.

Tritium levels in natural waters today have a similar value to the concentration before thermonuclear bomb testing conducted between 1954 and 1963. Because of the low concentration of this radioisotope, the analysis requires enrichment techniques to produce low detection limit, accurate results and to reduce uncertainties. This analysis includes preliminary distillation, electrolytic enrichment of the samples, the second distillation, and measurement on ultra low-level liquid scintillation spectrometer. The enrichment system consists of 16 electrolytic cells, each with a capacity of 250 ml, placed in the freezer and connected to a direct current source. One cell contains spike water with known tritium concentration and is used for enrichment factor determination. The initial volume for all samples is 250 ml. Na2O2 is used as an electrolyte to make the solution alkaline. Each cell has a gas outlet to ensure the escape of gases H2 and O2. In order to obtain a high enrichment factor, the system works on 5 A, to reduce the initial volume of the samples by 10-15 times. After electrolysis, second distillation must be performed to eliminate electrolyte. 8 ml of water sample after the second distillation is mixed with a scintillation cocktail in polyethylene vials and measured on a liquid scintillation spectrometer Quantulus 1220. At the end of the electrolytic enrichment process, the final volumes of the samples can be different, which causes different enrichment between the cells. To eliminate this influence, the final volume of all enrichment samples can be normalized at one value. In order to determine the corrected count rates obtained for each sample, the separation factor must be first calculated, taking into account initial volume, normalized final volume, count rate for spike water (after enrichment), count rate for spike water (before enrichment), and background count rate. In the example of one electrolysis, with 15 samples of drinking water, precipitation, and s

Ground Air Radioactivity Monitoring (GRAMON) database is a recently established collection containing activity concentrations of gamma emitters in aerosol samples. The measurements come from Serbia (sampling site Belgrade), Slovenia (sampling sites Ljubljana and Krško), Bosnia and Herzegovina (sampling site Sarajevo), Montenegro (sampling site Podgorica), and North Macedonia (sampling sites Skopje and Bitola), thus covering the northern and central parts of the Balkan Peninsula. As a database arising from the monitoring programmes in several countries, GRAMON is not fully homogeneous in terms of the radionuclides and time periods studied. For example, the beryllium-7 records are available for all sampling sites, while the lead-210 records only in Serbia, Slovenia, and Bosnia and Herzegovina. The time series for Serbia and Slovenia began in 1991, for Montenegro and North Macedonia in 2008, and for Bosnia and Herzegovina in 2010. However, sampling, sample preparation, and measurement procedures across the sites and laboratories are similar. In brief, aerosol samples are collected on filter papers using air samplers. Activity concentrations of radionuclides are determined by standard gamma spectrometry using high-purity germanium detectors. The time series contain monthly mean activity concentrations. Since only some of the GRAMON records have been previously published, this database provides a source for radioactivity research in the region that has been underrepresented in large-scale studies. We further hope to expand the number of contributing laboratories and cover a wider region of Europe, especially its southern and eastern parts.

This work presents the natural radioactivity distribution of 21 surface soil samples taken in the city of Novi Sad, Serbia. The analysis for radioactivity was performed using a gas low-level proportional counter for gross alpha and gross beta activity, while the specific activities of radionuclides were determined using HPGe detectors. The gross alpha activity of 20 samples was below the minimum detectable concentration (MDC), while in 1 sample it was 243 Bq kg−1; the gross beta activity ranged from the MDC (11 samples) to 566 Bq kg−1. The gamma spectrometry measurements showed naturally occurring radionuclides 226Ra, 232Th, 40K, and 238U in all investigated samples, with average values (Bq kg−1) of 33.9, 36.7, 513.8, and 34.7, respectively. Natural radionuclide 235U was detected in 18 samples with activity concentrations in the range of 1.3–4.1 Bq kg−1, while in the other 3 samples, the values were below the MDC. The artificial 137Cs radionuclide was detected in 90 percent of the samples, with a maximum value of 21 Bq kg−1, while the other artificial radionuclides were not detected. Based on the obtained concentrations of natural radionuclides, hazard indexes were estimated, and radiological health risk was assessed. The results present the absorbed gamma dose rate in the air, annual effective dose, radium equivalent activity, external hazard index, and lifetime cancer risk.