Radon intercomparison tests – Katowice, 2016

At the beginning of the year 2016, the representatives of the Polish Radon Centre decided to organize profi ciency tests (PTs) for measurements of radon gas and radon decay products in the air, involving radon monitors and laboratory passive techniques. The Silesian Centre for Environmental Radioactivity of the Central Mining Institute (GIG), Katowice, became responsible for the organization of the PT exercises. The main reason to choose that location was the radon chamber in GIG with a volume of 17 m3, the biggest one in Poland. Accordingly, 13 participants from Poland plus one participant from Germany expressed their interest. The participants were invited to inform the organizers about what types of monitors and methods they would like to check during the tests. On this basis, the GIG team prepared the proposal for the schedule of exercises, such as the required level(s) of radon concentrations, the number and periods of tests, proposed potential alpha energy concentration (PAEC) levels and also the overall period of PT. The PT activity was performed between 6th and 17th June 2016. After assessment of the results, the agreement between radon monitors and other measurement methods was confi rmed. In the case of PAEC monitors and methods of measurements, the results of PT exercises were consistent and confi rmed the accuracy of the calibration procedures used by the participants. The results of the PAEC PTs will be published elsewhere; in this paper, only the results of radon intercomparison are described

A Determination of the Concentration Level of Lead 210 PB Isotope in Solid Samples for the Assessment of Radiation Risk Occuring in Coal Mines

Lead 210Pb, an element of the natural uranium radioactive decay series, is not currently considered a source of radiation risk, especially in a radiation protection system in underground mines in Poland. However, it could be a completely independent element of the radioactive series due to its physical and chemical properties. Routine measurements showed significantly higher than expected concentrations of 210Pb in underground radium rich sediments, based only on the radioactive decay law. This phenomenon implies a need of 210Pb concentration monitoring in such sediments. Nevertheless, the laboratory analysis of 210Pb by gamma radiation spectroscopy is connected with a particular hindrance, the self-attenuation of 210Pb radiation in samples. Current work describes a practical method for obtaining the self-attenuation correction factor in the case of 210Pb concentration analysis. Experimentally obtained correction factors range between 0.51–6.96 cm2/g. Neglecting this factor can cause a significant error or underestimations in radiological risk assessment

Radon Concentrations in Dwellings in the Mining Area—Are There Observed Effects of the Coal Mine Closure?

The article presents the results of radon research, carried out in the area of the mining commune in the Upper Silesian Coal Basin (USCB), Poland. Past investigations in the 1990s on radon concentrations in buildings, located within the mining area, showed that the indoor radon concentrations measured in the area affected by mining were higher than in buildings located outside that area. Currently, all underground hard coal mines within the boundaries of the observed commune have been closed. In 2020, after the closure of the last active mine, radon measurements were started again. The current results of indoor radon concentrations were compared with the archival results from the 1990s. It was found that the radon concentration increased significantly in the basements of buildings where measurements were made in 1990, 2020, and 2021: the maximum values were 260 Bq/m3, 644 Bq/m3, and 1041 Bq/m3, respectively. Therefore, these questions were posed: Do the mine closure processes increase radon migration? How long is the period of the occurrence of changes in radon concentrations in buildings after the cessation of mining operations

The Determination of Radon/Thoron Exhalation Rate in an Underground Coal Mine—Preliminary Results

The objective of this work was to perform a series of measurements of radon and thoron exhalation in the underground workings of an experimental coal mine. In the years 2012–2015, experiments on underground coal gasification were carried out in a coal mine, which caused, among other effects, damage to rock mass. Afterward, periodic increases in the concentration of potential alpha energy (PAEC) of radon decay products in the air were found, which could pose a hazard to miners. The question posed was whether the gasification experiment resulted in the increased migration of radon and thoron. If so, did it increase the radiation hazard to miners? The adaptation of the existing instrumentation to the specific conditions was conducted, and a series of measurements were made. It was found that the measured values of radon and thoron exhalation rates ranged from 3.0 up to 38 Bq·m−2·h−1 for radon and from 500 up to 2000 Bq·m−2·h−1 for thoron

Zeolitized bottom ashes from biomass combustion as cement replacing components

In power plants biomass combustion produces large quantities of biomass bottom ash wastes. During the combustion process, the produced ashes are enriched in the radionuclides. The different enrichment of the various radionuclides within a radioactive series, such as that of 226Ra, 228Ra, 228Th, 40K, 210Pb and 137Cs results in the disturbance of radioactive secular equilibrium. The production of energy from renewable resources, such as biomass, is increasing rapidly. As the demand for bioenergy production increases, waste products from biomass combustion will increase too and will become a relevant environmental and economic problem. Therefore, environmentally friendly, and economic solutions to recycle the resulting by-products are essential. This research provides a real opportunity to save cement thus disposing the waste by using zeolitized biomass bottom ash as supplementary cementitious materials. The zeolitized products were examined by X-ray diffraction (XRD), X-ray fluorescence spectrometer (XRF) spectroscopy and high-resolution gamma spectrometry. In all investigated cases, compressive strength in hardened cement pastes and concrete samples slightly increases by replacing from 3% to 5% of Portland cement with zeolitized ashes. The results showed that natural radionuclides as 226Ra, 228Ra, 228Th, 40K are concentrated in similar way as in case of ashes obtained from combustion. However, addition of biomass leads to concentration of artificial radionuclide 137Cs that is still commonly present in biomass due to Chernobyl disaster. The observed activity concentration of 137Cs reaches the level of natural radionuclides concentration. Taking into consideration the contribution of 137Cs to gamma dose (usage of expanded activity index formula) may lead to exceeding the value of 1 in some cases. Calculated differences between activity indexes reach 13%Kauno technologijos universitetasVytauto Didžiojo universitetasŽemės ūkio akademij