Radon exhalation from fly-ash geopolymer mortar

Geopolymers are a type of alkali activated binders, inorganic aluminosilicate polymers with amorphous cross-linked structure. Fly-ash is produced in abundance during coal firing, and poses an environmental and health risk in untreated powder form. Fly-ash geopolymer presents a sustainable alternative to Portland cement, due to lower net greenhouse gas emissions. Presence of naturally occurring radioactive elements in fly-ash is one of the factors taken into account when estimating the safety of fly-ash based building materials. Radon, a radioactive noble gas originating from the decay of radium, can leave the material and contribute to internal dose in closed spaces, so radon exhalation is of special interest. Radon exhalation for a standard sample of fly-ash geopolymer mortar was measured

Sources of uncertainty in classification of radon zones

Evropski savet je doneo direktivu 2013/59/EURATOM (EU-BSS) po kojoj se nalaže državama članicama EU da imaju ustanovljen radonski akcioni plan, što između ostalog podrazumeva i identifikaciju radonskih prioritetnih zona (Radon priority areas), odnosno zona sa različitim nivoom "prioriteta". S obzirom da je neizvodljivo vršiti merenja radona u svakoj kući, potrebno je dizajnirati prospekciju radona kako bi se dobila reprezentativna procena srednje godišnje koncentracije radona u zatvorenim prostorijama na određenoj teritoriji. Nije bitan samo reprezentativan izbor kuća, nego je i nesigurnost merenja i procene srednje godišnje koncentracije potrebno držati što je niže moguće. Nesigurnostn klasifikacije zone određenog prioriteta u nekoj oblasti je stoga kombinacija nesigurnosti pojedinačnog merenja i ekstrapolacije tog merenja na celu oblast. U ovom radu ćemo pokušati da nabrojimo i procenimo izvore nesigurnosti pri klasifikaciji i damo preporuke u cilju smanjenja stepena nesigurnosti. Ovaj rad je urađen u sklopu MetroRadon projekta.The EC has laid down directive 2013/59/EURATOM which represents basic safety standards regarding the radon protection of the European citizens. Within the BSS they oblige countries to establish radon action plans which include identification of Radon Priority Areas (RPA). Since it is not feasible to perform indoor radon measurements in each dwelling, it is necessary to carefully design indoor radon survey in order to get representative estimation of annual average indoor radon concentration of the certain territory. It is not sufficient only to have representative selection of dwellings, but it is important to keep uncertainty of measurement and estimation of annual radon concentration as low as possible. Uncertainty of classification of radon zones is therefore combination of uncertainties coming from a single measurement uncertainty and uncertainty of extrapolation of single or group of measurements to the whole region. In this contribution, we will try to estimate sources of classification uncertainties and to give recommendation in order to reduce level of uncertainty. The research presented in this paper was realized within 16ENV04 MetroRADON project. This project has received funding from the EMPIR programme co-financed by the Participating States and from the European Union‘s Horizon 2020 research and innovation programme.Proceedings: [http://vinar.vin.bg.ac.rs/handle/123456789/8681]XXX симпозијум ДЗЗСЦГ (Друштва за заштиту од зрачења Србије и Црне Горе), 2- 4. октобар 2019. године, Дивчибаре, Србиј

MetroRADON - projekat za unapređenje merenja radona u Evropi

Трогодишњи пројекат MetroRADON у оквиру програма EMPIR је фокусиран на следљивост мерења ниске концентрације радона и доприноси стварању координиране метролошке инфраструктуре за мониторинг радона у Европи као и хармонизацији методологија мерења. Циљеви пројекта су да се обезбеди метролошка следљивост калибрације инструмената на ниским концентрацијама са мерном несигурношћу мањом од 5%, да се испита утицај торона и његових потомака на мерење концентрације радона, да се упореде процедуре мерења концентрације радона и брзине ексхалације радона из земљишта у различитим државама у Евопи, да се развију методе идентификацје области са повећаном концентрацијом радона, да се све ове методе валидују и да се олакша коришћење технологије и мерне инфраструктуре коју је развио пројекат од стране крајњих корисника. У овом раду ће бити дат преглед циљева и досадасшњих резултата пројекта.MetroRADON, a three year project based in the EMPIR program, is focused on traceability of low activity radon measurement. It contributes to the creation of the coordinated metrological infrastructure for radon monitoring in Europe, as well as the harmonization of measurement strategy and methodology. The objectives of this project is to secure the metrological traceability of the instrument calibration for the measurement of low activity, with the measurement uncertainty that does not exceed 5%, to investigate the influence of thoron and its progenies on the radon concentration measurements, to compare procedures for measurement of indoor radon concentration and exhalation rate from the soil in different European countries, to develop methods for recognizing the radon priority areas and finally to validate these methods, but at the same time to enable the access of the final users to the measurement technology and infrastructure developed within this project. This paper presents the overview of these objectives and the results achieved in the present time.Proceedings: [http://vinar.vin.bg.ac.rs/handle/123456789/8681]XXX симпозијум ДЗЗСЦГ (Друштва за заштиту од зрачења Србије и Црне Горе), 2- 4. октобар 2019. године, Дивчибаре, Србиј

Qualitative overview of indoor radon surveys in Europe

The revised European Directive from 2013 regarding basic safety standard oblige EU Member States to establish a national action plan regarding the exposure to radon. At the same time, International Atomic Energy Agency started technical projects in order to assist countries to establish and implement national radon action. As a consequence, in recent years, in numerous countries national radon surveys were conducted and action plans established, which were not performed before. In this paper, a qualitative overview of radon surveys performed in Europe is given with a special attention to the qualitative and conceptual description of surveys, representativeness and QA/QC (quality assurance/quality control). © 201

Radon and thoron exhalation rate measurements from building materials used in Serbia

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

Sezonse varijacije koncentracije radona

Након измерене високе концентрације радона у три просторије у једној кући почетком 2018. године, настављено је испитивање концентрације у свим годишњим добима, а број просторија је повећан на пет. Као што је очекивано, концентрација радона је у току летњих месеци била много мања него у зимском периоду, првенствено због сталног проветравања. У осталим годишњим добима уочена је велико повећање коцентрације радона са смањењем спољашње температуре. Такође је уочено смањење концентрације радона у свим просто-ријама наредне зиме, за приближно исти хладни период, када је уместо угља коришћен дрвени пелет.The high radon concentrations were measured in three rooms in one house at the beginning of 2018. After that, radon testing was continued during all seasons and the number of rooms was increased to five. As expected, the concentration of radon during the summer was much lower than in the winter period, primarily due to constant natural ventilation. In other seasons, a large increase in radon concentration with a decrease in the outside temperature was observed. There was also a decrease in radon concentrations in all rooms in the following winter, in approximately the same cold period, when wood pellets were used instead of coal.Proceedings: [http://vinar.vin.bg.ac.rs/handle/123456789/8681]XXX симпозијум ДЗЗСЦГ (Друштва за заштиту од зрачења Србије и Црне Горе), 2- 4. октобар 2019. године, Дивчибаре, Србиј

Outdoor Radon as a Tool to Estimate Radon Priority Areas—A Literature Overview

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

Overview of Radon Flux Characteristics, Measurements, Models and Its Potential Use for the Estimation of Radon Priority Areas

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

Toward the limit of nuclear binding on the N=Z line : Spectroscopy of Cd 96

A γ-decaying isomeric state (τ1/2=197-17+19 ns) has been identified in Cd96, which is one α particle away from the last known bound N=Z nucleus, Sn100. Comparison of the results with shell-model calculations has allowed a tentative experimental level scheme to be deduced and the isomer to be interpreted as a medium-spin negative-parity spin trap based on the coupling of isoscalar (T=0) and isovector (T=1) neutron-proton pairs. The data also suggest evidence for the population of a 9+ T=1 state, which is predicted by shell-model calculations to be yrast. Such a low-lying T=1 state, which is unknown in lighter mass even-even self-conjugate nuclei, can also be interpreted in terms of the coupling of T=0 and T=1 neutron-proton pairs