https://doi.org/10.1140/epjp/s13360-025-06526-3
Regular Article
Analyses of slag and ash samples performed between 2019 and 2023, with a focus on radioactive equilibrium in natural decay series
National Radiation Protection Institute (SURO), Bartoškova 28, 140 00, Prague, Czech Republic
Received:
5
December
2024
Accepted:
6
June
2025
Published online:
24
June
2025
Products of coal combustion (especially ash and slag) are commonly used as raw materials in the production of building materials. Such building materials need to meet the legislative criteria based on the determination of 40 K, 226Ra and 232Th activities, which are used for the Activity Concentration Index calculation. The Czech national authority issued a Recommendation concerning gamma spectrometric activity assessment in building materials. This document assumes an intact radioactive equilibrium in the decay series; therefore, 226Ra does not have to be determined from the activities of radon daughters. Instead, it can be determined directly from the 186 keV peak, with 226Ra making up 57.5% of the total peak area. This approach significantly simplifies and shortens the determination of 226Ra, since the sample containers do not have to be hermetically sealed and there is no need to wait for the equilibrium. From 2019 to 2023, the National Radiation Protection Institute analysed over 139 slag and ash samples produced in the Czech Republic. The 226Ra activity concentration was determined from the daughter products of radon decay (214Bi and 214Pb) and directly from the 186 keV peak. The 238U activity concentration was determined from decay products (234 mPa or 234Th) and by calculation from 235U. Based on the statistical comparison of the activities obtained using different approaches, the assumption of the equilibrium in the decay series can be verified.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2025
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
