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Rosabianca Trevisi - One of the best experts on this subject based on the ideXlab platform.
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A study on natural radioActivity and radon exhalation rate in building materials containing norm residues: preliminary results
Construction and Building Materials, 2018Co-Authors: Federica Leonardi, Cristina Nuccetelli, Michał Bonczyk, Małgorzata Wysocka, B. Michalik, M. Ampollini, S. Tonnarini, Jan Antoni Rubin, K. Niedbalska, Rosabianca TrevisiAbstract:Abstract This paper contains preliminary results of a study on the physical and radiological characterization of concrete samples containing NORM. The natural radionuclides content in term of 226Ra, 228Ra, 232Th, 40K and the radon exhalation rate of the samples were determined. Two series of samples of concrete were prepared: samples belonging to both series were made of the same basic components (Portland cement CEM I 42,5R as binder, aggregate and plasticizer) but different amount of NORM residues and mineral additives were used. The concrete samples were characterize in term of absolute density, permeability, total and open porosity. The radiological content was evaluated by using gamma spectrometry and the radon exhalation rate measurements were performed using the dynamic method. Moreover, the Activity Concentration Index (I), introduced by the 2013/59/Euratom Directive, has been used in order to evaluate if concrete samples could exceed the reference level for effective dose due to gamma radiation in building materials.
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Gamma exposure from building materials – A dose model with expanded gamma lines from naturally occurring radionuclides applicable in non-standard rooms
Construction and Building Materials, 2018Co-Authors: Tom Croymans, Cristina Nuccetelli, Rosabianca Trevisi, Sonja Schreurs, Federica Leonardi, Wouter SchroeyersAbstract:Abstract Building materials are a significant source of gamma rays exposure due to the presence of naturally occurring radionuclides. In order to protect the public from harmful radiation, the European Basic Safety Standards (Council directive 2013/59/Euratom) (European Council, 2014) introduced a one-size-fits-all building(s) (materials) Activity Concentration Index (ACI) based on a limited set of gamma lines. The ACI is considered “as a conservative screening tool for identifying materials that may cause the reference level (i.e. 1 mSv/y) laid down in article 75(1) to be exceeded”. Regarding calculation of dose, many factors such as density and thickness of the building material, as well as factors relating to the type of building, and the gamma emission data need to be taking into account to ensure accurate radiation protection. In this study the implementation of an expanded set of 1845 gamma lines, related to the decay series of 238U, 235U and 232Th as well as to 40K, into the calculation method of Markkanen (1995), is discussed. The expanded calculation method is called the Expanded Gamma Dose Assessment (EGDA) model. The total gamma emission intensity increased from 2.12 to 2.41 and from 2.41 to 3.04 for respectively the 238U and 232Th decay series. In case of 40K a decrease from 0.107 to 0.106 is observed. The 235U decay series is added, having a gamma emission intensity of 3.1. In a standard concrete room, the absorbed dose rates in air (DA) per unit of Activity Concentration of 0.849, 0.256, 1.08, 0.0767 nGy/h per Bq/kg are observed. The use of weighted average gamma lines increased the DA with 6.5% and 1% for respectively the 238U and 232Th decay series. A decrease of 4.5% is observed in the DA of 235U decay series when using the weighted average gamma lines in comparison to its non-averaged variant. The sensitivity of the EGDA model for density, wall thickness, presence of windows and doors and room size is investigated. Finally, a comparison of the Index and dose calculations relevant for the dose assessment within the European legislative framework applicable towards building materials is performed. In cases where the ACI and density and thickness corrected dose calculation of Nuccetelli et al. (2015) cannot provide guidance, the EGDA allows performing more accurate dose assessment calculations leading to effective doses which can be several 100 µSv/y lower.
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Alkali-activated concrete with Serbian fly ash and its radiological impact.
Journal of environmental radioactivity, 2016Co-Authors: Cristina Nuccetelli, Rosabianca Trevisi, Ivan Ignjatović, Jelena DragašAbstract:Abstract The present paper reports the results of a study on different types of fly ash from Serbian coal burning power plants and their potential use as a binder in alkali-activated concrete (AAC) depending on their radiological and mechanical properties. Five AAC mixtures with different types of coal burning fly ash and one type of blast furnace slag were designed. Measurements of the Activity Concentrations of 40 K, 226 Ra and 232 Th were done both on concrete constituents (fly ash, blast furnace slag and aggregate) and on the five solid AAC samples. Experimental results were compared by using the Activity Concentration assessment tool for building materials - the Activity Concentration Index I, as introduced by the EU Basic Safety Standards (CE, 2014). All five designed alkali-activated concretes comply with EU BSS screening requirements for indoor building materials. Finally, Index I values were compared with the results of the application of a more accurate Index - I(ρd), which accounts for thickness and density of building materials (Nuccetelli et al., 2015a). Considering the actual density and thickness of each concrete sample Index - I(ρd) values are lower than Index I values. As an appendix, a synthesis of main results concerning mechanical and chemical properties is provided.
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A new accurate and flexible Index to assess the contribution of building materials to indoor gamma exposure
Journal of environmental radioactivity, 2015Co-Authors: Cristina Nuccetelli, Federica Leonardi, Rosabianca TrevisiAbstract:The role of building materials as a source of gamma radiation has been recognized in the new EU Basic Safety Standards Directive which introduces an Index I to screen building materials of radiological concern. This Index was developed to account for average concrete values of thickness and density, the main structural characteristics of building materials that have an effect on gamma irradiation. Consequently, this screening procedure could be unfit in case of significantly different density and/or thickness of the building materials under examination. The paper proposes a more accurate and flexible Activity Concentration Index, accounting for the actual density and thickness of building materials.
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New perspectives and issues arising from the introduction of (NORM) residues in building materials: A critical assessment on the radiological behaviour
Construction and Building Materials, 2015Co-Authors: Cristina Nuccetelli, Federica Leonardi, Yiannis Pontikes, Rosabianca TrevisiAbstract:The goal of this paper is twofold, that is, (a) to provide an overview of the radiometric content of residues and by-products used in building material production; (b) to evaluate the radiological impact of building products containing these materials, by using the European Union Activity Concentration Index I and the computational ISS room model. To achieve the above, coal ash, blast furnace slag, phosphogypsum and bauxite residues are assessed with data from EU countries and industries worldwide. In terms of radiological assessment, the ISS room model is employed as a computational tool, providing an accurate and specific estimate of the contribution of building materials to the indoor dose. As a result, the work herein aspires to provide the framework based upon a residue will be evaluated as a candidate secondary resource with respect to its radiological content.
Cristina Nuccetelli - One of the best experts on this subject based on the ideXlab platform.
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A study on natural radioActivity and radon exhalation rate in building materials containing norm residues: preliminary results
Construction and Building Materials, 2018Co-Authors: Federica Leonardi, Cristina Nuccetelli, Michał Bonczyk, Małgorzata Wysocka, B. Michalik, M. Ampollini, S. Tonnarini, Jan Antoni Rubin, K. Niedbalska, Rosabianca TrevisiAbstract:Abstract This paper contains preliminary results of a study on the physical and radiological characterization of concrete samples containing NORM. The natural radionuclides content in term of 226Ra, 228Ra, 232Th, 40K and the radon exhalation rate of the samples were determined. Two series of samples of concrete were prepared: samples belonging to both series were made of the same basic components (Portland cement CEM I 42,5R as binder, aggregate and plasticizer) but different amount of NORM residues and mineral additives were used. The concrete samples were characterize in term of absolute density, permeability, total and open porosity. The radiological content was evaluated by using gamma spectrometry and the radon exhalation rate measurements were performed using the dynamic method. Moreover, the Activity Concentration Index (I), introduced by the 2013/59/Euratom Directive, has been used in order to evaluate if concrete samples could exceed the reference level for effective dose due to gamma radiation in building materials.
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Radiological aspects for use of woodchip ashes in building industry
Construction and Building Materials, 2018Co-Authors: Massimo Garavaglia, Cristina Nuccetelli, Silvia Bucci, Elena Caldognetto, Giuseppe Candolini, Massimo Faure Ragani, Concettina Giovani, M. Magnoni, Ilaria Peroni, R. RusconiAbstract:Abstract The use of woodchips of local origin for heating purposes is a diffused practice in some areas, like northern Italian alpine and sub-alpine zones, where large woods and forests extensions occur. In recent years, many thermal plants producing energy using woodchips as fuel have been constructed, supplying single edifices and delivering heated water to small communities through district heating. Unfortunately, due to the Chernobyl fall-out, particularly relevant in many mountain areas of northern Italy, woodchips of local origin are often contaminated with relevant 137 Cs traces: therefore, the woodchips burning aimed at water heating produces ashes in which the 137 Cs Activity Concentration is highly enriched with respect to that of the raw material. Typical Activity Concentrations of 137 Cs in such ashes span a range from a few hundreds to several thousands Bq/kg. These combustion ashes are subject to different fates, according to reuse opportunities and law restrictions (not referred to the radiological aspects). Landfill disposal is the most common general option, together with the use in compost production plants and concrete factories. In this paper, we focused in particular to the use of concrete containing highly contaminated ashes, being considered as the most relevant from the radioprotection point of view. Therefore, some evaluations of the public exposure to radiations coming from concrete utilized as building material and containing woodchip ashes with high radioActivity levels (specifically 137 Cs and 40 K) have been done. The dose estimates for a person living in a house built with “contaminated” concrete were made using both standardized gamma radiation exposure indices and simulation models. The results are presented and discussed. Finally, a new formulation of the Activity Concentration Index I is proposed for a safe and radioprotection sound use of building material containing woodchip ashes.
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Gamma exposure from building materials – A dose model with expanded gamma lines from naturally occurring radionuclides applicable in non-standard rooms
Construction and Building Materials, 2018Co-Authors: Tom Croymans, Cristina Nuccetelli, Rosabianca Trevisi, Sonja Schreurs, Federica Leonardi, Wouter SchroeyersAbstract:Abstract Building materials are a significant source of gamma rays exposure due to the presence of naturally occurring radionuclides. In order to protect the public from harmful radiation, the European Basic Safety Standards (Council directive 2013/59/Euratom) (European Council, 2014) introduced a one-size-fits-all building(s) (materials) Activity Concentration Index (ACI) based on a limited set of gamma lines. The ACI is considered “as a conservative screening tool for identifying materials that may cause the reference level (i.e. 1 mSv/y) laid down in article 75(1) to be exceeded”. Regarding calculation of dose, many factors such as density and thickness of the building material, as well as factors relating to the type of building, and the gamma emission data need to be taking into account to ensure accurate radiation protection. In this study the implementation of an expanded set of 1845 gamma lines, related to the decay series of 238U, 235U and 232Th as well as to 40K, into the calculation method of Markkanen (1995), is discussed. The expanded calculation method is called the Expanded Gamma Dose Assessment (EGDA) model. The total gamma emission intensity increased from 2.12 to 2.41 and from 2.41 to 3.04 for respectively the 238U and 232Th decay series. In case of 40K a decrease from 0.107 to 0.106 is observed. The 235U decay series is added, having a gamma emission intensity of 3.1. In a standard concrete room, the absorbed dose rates in air (DA) per unit of Activity Concentration of 0.849, 0.256, 1.08, 0.0767 nGy/h per Bq/kg are observed. The use of weighted average gamma lines increased the DA with 6.5% and 1% for respectively the 238U and 232Th decay series. A decrease of 4.5% is observed in the DA of 235U decay series when using the weighted average gamma lines in comparison to its non-averaged variant. The sensitivity of the EGDA model for density, wall thickness, presence of windows and doors and room size is investigated. Finally, a comparison of the Index and dose calculations relevant for the dose assessment within the European legislative framework applicable towards building materials is performed. In cases where the ACI and density and thickness corrected dose calculation of Nuccetelli et al. (2015) cannot provide guidance, the EGDA allows performing more accurate dose assessment calculations leading to effective doses which can be several 100 µSv/y lower.
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Alkali-activated concrete with Serbian fly ash and its radiological impact.
Journal of environmental radioactivity, 2016Co-Authors: Cristina Nuccetelli, Rosabianca Trevisi, Ivan Ignjatović, Jelena DragašAbstract:Abstract The present paper reports the results of a study on different types of fly ash from Serbian coal burning power plants and their potential use as a binder in alkali-activated concrete (AAC) depending on their radiological and mechanical properties. Five AAC mixtures with different types of coal burning fly ash and one type of blast furnace slag were designed. Measurements of the Activity Concentrations of 40 K, 226 Ra and 232 Th were done both on concrete constituents (fly ash, blast furnace slag and aggregate) and on the five solid AAC samples. Experimental results were compared by using the Activity Concentration assessment tool for building materials - the Activity Concentration Index I, as introduced by the EU Basic Safety Standards (CE, 2014). All five designed alkali-activated concretes comply with EU BSS screening requirements for indoor building materials. Finally, Index I values were compared with the results of the application of a more accurate Index - I(ρd), which accounts for thickness and density of building materials (Nuccetelli et al., 2015a). Considering the actual density and thickness of each concrete sample Index - I(ρd) values are lower than Index I values. As an appendix, a synthesis of main results concerning mechanical and chemical properties is provided.
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A new accurate and flexible Index to assess the contribution of building materials to indoor gamma exposure
Journal of environmental radioactivity, 2015Co-Authors: Cristina Nuccetelli, Federica Leonardi, Rosabianca TrevisiAbstract:The role of building materials as a source of gamma radiation has been recognized in the new EU Basic Safety Standards Directive which introduces an Index I to screen building materials of radiological concern. This Index was developed to account for average concrete values of thickness and density, the main structural characteristics of building materials that have an effect on gamma irradiation. Consequently, this screening procedure could be unfit in case of significantly different density and/or thickness of the building materials under examination. The paper proposes a more accurate and flexible Activity Concentration Index, accounting for the actual density and thickness of building materials.
Wouter Schroeyers - One of the best experts on this subject based on the ideXlab platform.
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Radiological evaluation of industrial residues for construction purposes correlated with their chemical properties
The Science of the total environment, 2018Co-Authors: Zoltan Sas, Niels Vandevenne, Rory Doherty, Raffaele Vinai, Jacek Kwasny, Mark Russell, Wei Sha, Marios Soutsos, Wouter SchroeyersAbstract:Abstract This study characterises the naturally occurring radionuclide (NOR) contents of a suite of secondary raw materials or industrial residues that are normally disposed of in landfills or lagoons but now are increasingly used in green concretes. This includes ashes from a variety of industrial processes and red mud from aluminium production, as well as air pollution control residue and cement kiln dust. The chemical composition of the samples was determined with X-ray fluorescence spectroscopy (XRF). The Ra-226, Th-232 and K-40 Activity Concentrations were obtained by gamma spectrometry, and the results were compared with recently published NOR databases. The correlation between the NOR contents and the main chemical composition was investigated. The radioactive equilibrium in the U-238 chain was studied based on the determination of progeny isotopes. The most commonly used calculation methods (Activity Concentration Index and radium equivalent Concentration) were applied to classify the samples. The radon exhalation rate of the samples was measured, and the radon emanation coefficient was calculated. Significant correlation was found between the NORs and certain chemical components. The massic exhalation demonstrated a broad range, and it was found that the emanation coefficients were significantly lower in the case of the residues generated as a result of high-temperature combustion processes. The results showed a weak correlation between the Ra-226 Concentration and the radon exhalation. This emphasises that managing the Ra-226 content of recycled material by itself is not sufficient to control the radon exhalation of recycled materials used in building products. The investigated parameters and their correlation behaviour could be used to source apportion materials found during the process of landfill mining and recovery of material for recycling.
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Measurement of radioActivity in building materials – Problems encountered caused by possible disequilibrium in natural decay series
Construction and Building Materials, 2018Co-Authors: Boguslaw Michalik, Wouter SchroeyersAbstract:Abstract The determination of the Activity Concentration of naturally occurring radionuclides in construction materials is based on the principles of gamma-spectrometry. Gamma spectrometry is a comparative method and therefore includes many parameters that are specific to the test sample and measurement circumstances. Consequently, several of the testing conditions must be verified prior to testing and/or require correction to obtain accurate results. Besides problems encountered during the measurement, the interpretation of the results and calculation of the Activity indices, needed for material classification, may lead to significant mistakes. Current regulation in the European Union requires to calculate an Activity Concentration Index (Index I) using the Activity Concentration of 226Ra, 232Th and 40K. Not all of these radionuclides are directly measurable by gamma spectrometry and, to determine the Index, additional assumptions have to be made about secular equilibrium in uranium and thorium decay series. These assumptions are often not valid in case of NORM (Naturally Occurring Radioactive Materials) where long term lack of secular equilibrium in the uranium and/or thorium decay series is often observed. As a consequence, this may result in an underestimation or overestimation of the Index. The article discusses specific disequilibrium situations in building materials. Sources for potential inaccurate determinations and misinterpretation are identified and practical mitigation options are proposed.
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Gamma exposure from building materials – A dose model with expanded gamma lines from naturally occurring radionuclides applicable in non-standard rooms
Construction and Building Materials, 2018Co-Authors: Tom Croymans, Cristina Nuccetelli, Rosabianca Trevisi, Sonja Schreurs, Federica Leonardi, Wouter SchroeyersAbstract:Abstract Building materials are a significant source of gamma rays exposure due to the presence of naturally occurring radionuclides. In order to protect the public from harmful radiation, the European Basic Safety Standards (Council directive 2013/59/Euratom) (European Council, 2014) introduced a one-size-fits-all building(s) (materials) Activity Concentration Index (ACI) based on a limited set of gamma lines. The ACI is considered “as a conservative screening tool for identifying materials that may cause the reference level (i.e. 1 mSv/y) laid down in article 75(1) to be exceeded”. Regarding calculation of dose, many factors such as density and thickness of the building material, as well as factors relating to the type of building, and the gamma emission data need to be taking into account to ensure accurate radiation protection. In this study the implementation of an expanded set of 1845 gamma lines, related to the decay series of 238U, 235U and 232Th as well as to 40K, into the calculation method of Markkanen (1995), is discussed. The expanded calculation method is called the Expanded Gamma Dose Assessment (EGDA) model. The total gamma emission intensity increased from 2.12 to 2.41 and from 2.41 to 3.04 for respectively the 238U and 232Th decay series. In case of 40K a decrease from 0.107 to 0.106 is observed. The 235U decay series is added, having a gamma emission intensity of 3.1. In a standard concrete room, the absorbed dose rates in air (DA) per unit of Activity Concentration of 0.849, 0.256, 1.08, 0.0767 nGy/h per Bq/kg are observed. The use of weighted average gamma lines increased the DA with 6.5% and 1% for respectively the 238U and 232Th decay series. A decrease of 4.5% is observed in the DA of 235U decay series when using the weighted average gamma lines in comparison to its non-averaged variant. The sensitivity of the EGDA model for density, wall thickness, presence of windows and doors and room size is investigated. Finally, a comparison of the Index and dose calculations relevant for the dose assessment within the European legislative framework applicable towards building materials is performed. In cases where the ACI and density and thickness corrected dose calculation of Nuccetelli et al. (2015) cannot provide guidance, the EGDA allows performing more accurate dose assessment calculations leading to effective doses which can be several 100 µSv/y lower.
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Variation of natural radionuclides in non-ferrous fayalite slags during a one-month production period
Journal of environmental radioactivity, 2017Co-Authors: Tom Croymans, Sonja Schreurs, Indy Vandael Schreurs, Mikael Hult, Gerd Marissens, Guillaume Lutter, H. Stroh, Wouter SchroeyersAbstract:Abstract The European Basic Safety Standards (EU-BSS) describes a set of NORM (Naturally Occurring Radioactive Material)-processing industries which produce residues known to be possibly enriched in NORs (Naturally Occurring Radionuclides). These residues can be used as a component in building materials aimed for public usage. The industrial processes, in which the residues are produced, are often complex and total monitoring can be challenging especially when the origin of the used raw materials varies. In this study the NORs present in non-ferrous fayalite slags of a secondary smelter facility, a NORM-processing industry according to the EU-BSS, were monitored daily during a one-month production period. In addition flue dust samples and feedstock samples, known to contain elevated levels of NORs, of the same period were measured. The survey involved the gamma-ray spectrometric analysis of the decay products from the 238 U and 232 Th decay chains, 235 U and 40 K using HPGe detectors. Secular equilibrium was observed for the slags, flue dust and feedstock samples in the 232 Th decay chain, in contrast to the 238 U decay chain. During the month in question the ratios of maximum over minimum Activity Concentration were 3.1 ± 0.5 for 40 K, 4 ± 1 for 238 U, 6 ± 1 for 226 Ra, 13 ± 7 for 210 Pb, 4.5 ± 0.6 for 228 Ra and 4.7 ± 0.7 for 228 Th for the slags. Even with the Activity Concentration of the feedstock material ranging up to 2.1 ± 0.3 kBq/kg for 238 U, 1.6 ± 0.2 kBq for 226 Ra, 22 ± 7 kBq/kg for 210 Pb, 2.1 ± 0.2 kBq/kg for 228 Ra and 2.0 ± 0.4 kBq/kg for 228 Th, none of the slag samples exceeded the exemption/clearance levels of the EU-BSS and RP-122 part II, which can respectively provide guidance under equilibrium and in absence of equilibrium. As each NORM-processing industry has its own complexity and variability, the observed variations point out that one should approach one-time measurements or low frequency monitoring methods cautiously. Low frequency measurements should be optimised depending on the discharge of the batches. A follow up of the industrial process and its output can provide important insights to assure a limited public exposure upon application of these industrial residues. Finally a comparison is made with reported data on other metallurgical slags and the use of the slags in building materials is evaluated using the Activity Concentration Index (ACI) proposed by the EU-BSS.
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The use of portable equipment for the Activity Concentration Index determination of building materials: method validation and survey of building materials on the Belgian market.
Journal of environmental radioactivity, 2013Co-Authors: Mark Stals, S. Verhoeven, M. Bruggeman, V. Pellens, Wouter Schroeyers, Sonja SchreursAbstract:Abstract The Euratom BSS requires that in the near future (2015) the building materials for application in dwellings or buildings such as offices or workshops are screened for NORM nuclides. The screening tool is the Activity Concentration Index (ACI). Therefore it is expected that a large number of building materials will be screened for NORM and thus require ACI determination. Nowadays, the proposed standard for determination of building material ACI is a laboratory analyses technique with high purity germanium spectrometry and 21 days equilibrium delay. In this paper, the B-NORM method for determination of building material ACI is assessed as a faster method that can be performed on-site, alternative to the aforementioned standard method. The B-NORM method utilizes a LaBr 3 (Ce) scintillation probe to obtain the spectral data. Commercially available software was applied to comprehensively take into account the factors determining the counting efficiency. The ACI was determined by interpreting the gamma spectrum from 226 Ra and its progeny; 232 Th progeny and 40 K. In order to assess the accuracy of the B-NORM method, a large selection of samples was analyzed by a certified laboratory and the results were compared with the B-NORM results. The results obtained with the B-NORM method were in good correlation with the results obtained by the certified laboratory, indicating that the B-NORM method is an appropriate screening method to assess building material ACI. The B-NORM method was applied to analyze more than 120 building materials on the Belgian market. No building materials that exceed the proposed reference level of 1 mSv/year were encountered.
Federica Leonardi - One of the best experts on this subject based on the ideXlab platform.
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A study on natural radioActivity and radon exhalation rate in building materials containing norm residues: preliminary results
Construction and Building Materials, 2018Co-Authors: Federica Leonardi, Cristina Nuccetelli, Michał Bonczyk, Małgorzata Wysocka, B. Michalik, M. Ampollini, S. Tonnarini, Jan Antoni Rubin, K. Niedbalska, Rosabianca TrevisiAbstract:Abstract This paper contains preliminary results of a study on the physical and radiological characterization of concrete samples containing NORM. The natural radionuclides content in term of 226Ra, 228Ra, 232Th, 40K and the radon exhalation rate of the samples were determined. Two series of samples of concrete were prepared: samples belonging to both series were made of the same basic components (Portland cement CEM I 42,5R as binder, aggregate and plasticizer) but different amount of NORM residues and mineral additives were used. The concrete samples were characterize in term of absolute density, permeability, total and open porosity. The radiological content was evaluated by using gamma spectrometry and the radon exhalation rate measurements were performed using the dynamic method. Moreover, the Activity Concentration Index (I), introduced by the 2013/59/Euratom Directive, has been used in order to evaluate if concrete samples could exceed the reference level for effective dose due to gamma radiation in building materials.
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Gamma exposure from building materials – A dose model with expanded gamma lines from naturally occurring radionuclides applicable in non-standard rooms
Construction and Building Materials, 2018Co-Authors: Tom Croymans, Cristina Nuccetelli, Rosabianca Trevisi, Sonja Schreurs, Federica Leonardi, Wouter SchroeyersAbstract:Abstract Building materials are a significant source of gamma rays exposure due to the presence of naturally occurring radionuclides. In order to protect the public from harmful radiation, the European Basic Safety Standards (Council directive 2013/59/Euratom) (European Council, 2014) introduced a one-size-fits-all building(s) (materials) Activity Concentration Index (ACI) based on a limited set of gamma lines. The ACI is considered “as a conservative screening tool for identifying materials that may cause the reference level (i.e. 1 mSv/y) laid down in article 75(1) to be exceeded”. Regarding calculation of dose, many factors such as density and thickness of the building material, as well as factors relating to the type of building, and the gamma emission data need to be taking into account to ensure accurate radiation protection. In this study the implementation of an expanded set of 1845 gamma lines, related to the decay series of 238U, 235U and 232Th as well as to 40K, into the calculation method of Markkanen (1995), is discussed. The expanded calculation method is called the Expanded Gamma Dose Assessment (EGDA) model. The total gamma emission intensity increased from 2.12 to 2.41 and from 2.41 to 3.04 for respectively the 238U and 232Th decay series. In case of 40K a decrease from 0.107 to 0.106 is observed. The 235U decay series is added, having a gamma emission intensity of 3.1. In a standard concrete room, the absorbed dose rates in air (DA) per unit of Activity Concentration of 0.849, 0.256, 1.08, 0.0767 nGy/h per Bq/kg are observed. The use of weighted average gamma lines increased the DA with 6.5% and 1% for respectively the 238U and 232Th decay series. A decrease of 4.5% is observed in the DA of 235U decay series when using the weighted average gamma lines in comparison to its non-averaged variant. The sensitivity of the EGDA model for density, wall thickness, presence of windows and doors and room size is investigated. Finally, a comparison of the Index and dose calculations relevant for the dose assessment within the European legislative framework applicable towards building materials is performed. In cases where the ACI and density and thickness corrected dose calculation of Nuccetelli et al. (2015) cannot provide guidance, the EGDA allows performing more accurate dose assessment calculations leading to effective doses which can be several 100 µSv/y lower.
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A new accurate and flexible Index to assess the contribution of building materials to indoor gamma exposure
Journal of environmental radioactivity, 2015Co-Authors: Cristina Nuccetelli, Federica Leonardi, Rosabianca TrevisiAbstract:The role of building materials as a source of gamma radiation has been recognized in the new EU Basic Safety Standards Directive which introduces an Index I to screen building materials of radiological concern. This Index was developed to account for average concrete values of thickness and density, the main structural characteristics of building materials that have an effect on gamma irradiation. Consequently, this screening procedure could be unfit in case of significantly different density and/or thickness of the building materials under examination. The paper proposes a more accurate and flexible Activity Concentration Index, accounting for the actual density and thickness of building materials.
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New perspectives and issues arising from the introduction of (NORM) residues in building materials: A critical assessment on the radiological behaviour
Construction and Building Materials, 2015Co-Authors: Cristina Nuccetelli, Federica Leonardi, Yiannis Pontikes, Rosabianca TrevisiAbstract:The goal of this paper is twofold, that is, (a) to provide an overview of the radiometric content of residues and by-products used in building material production; (b) to evaluate the radiological impact of building products containing these materials, by using the European Union Activity Concentration Index I and the computational ISS room model. To achieve the above, coal ash, blast furnace slag, phosphogypsum and bauxite residues are assessed with data from EU countries and industries worldwide. In terms of radiological assessment, the ISS room model is employed as a computational tool, providing an accurate and specific estimate of the contribution of building materials to the indoor dose. As a result, the work herein aspires to provide the framework based upon a residue will be evaluated as a candidate secondary resource with respect to its radiological content.
Francisca Puertas - One of the best experts on this subject based on the ideXlab platform.
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olive biomass ash as an alternative activator in geopolymer formation a study of strength radiology and leaching behaviour
Cement & Concrete Composites, 2019Co-Authors: M.m. Alonso, C. Gascó, J A Suareznavarro, Martin M Morales, M Zamorano, Francisca PuertasAbstract:Abstract Chemical, physical, mineralogical and radiological characterization of olive biomass fly ash (OBFA) and bottom ash (OBBA) was main objective to determine their potential use as alkaline activators in the preparation of alkali-activated materials or geopolymers. Water solubility tests showed that they released K and Na ions, affording a high pH and alkaline content. Pastes made with 70 wt% vitreous blast furnace slag (SL) and 30 wt% of OBFA or OBBA yielded alkali-activated materials with 28 days mechanical strength of 33 to 18 MPa. In pastes prepared with 30 wt% OBFA, strength values were comparable to those developed by slag pastes activated with a commercial KOH. However, the pastes made with 70 wt% coal fly ash and 30 wt% OBFA or OBBA proved to be inviable because the pH reached was not high enough to activate the precursor. The radiological calculations of OBFA- and OBBA-SL bearing pastes would conform to European legislation on protection against exposure to ionising radiation, for the Activity Concentration Index (ACI) found in the final product was less than 1 in all cases. The pastes leached primarily K. The presence of elements such as 210Po and 210 Pb at the end of the decay chain in the eluates would not limit the use of biomass ash and slag blends. These findings have confirmed the feasibility of using olive oil biomass ashes as an alternative alkaline activator in blast furnace slag systems to produce alkali-activated materials or geopolymers, with properties that make them apt for use as building materials.
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Radiological behaviour of pigments and water repellents in cement-based mortars
Construction and Building Materials, 2019Co-Authors: J. A. Suárez-navarro, M.m. Alonso, C. Gascó, Marcos Lanzón, María Teresa Blanco-varela, A. M. Moreno-reyes, Francisca PuertasAbstract:Abstract The use of admixtures in mortars to improve both their physical-chemical and ornamental features has become increasingly common in recent years. The varying origin and composition of these products, some sourced from waste produced in other industries, poses the question of whether they modify the Activity Concentration Index (ACI) of the construction materials to which they are added. Seven pigments, some of natural and others of artificial origin, and two water repellents were characterised both chemically and radiologically in this study. Neither the synthetic pigments nor the water repellents exhibited significant radiological content. The pigments based on Fe2O3 of natural origin had detectable Activity Concentrations of naturally occurring radionuclides from the 238U series. Those levels were attributable to the raw material used, namely the bauxite red mud generated in aluminium production. In addition to Si, Al, Fe, Ca, Ti and Na as majority elements, this sludge also contains traces of K, Cr, V, Ba, Cu, Mn, Pb, Zn, P, F, S and As, among others, including naturally occurring uranium. The public and occupational radiological risk due to exposure to pigment-modified construction materials were consequently assessed. Neither the doses for the public at large and for workers were found neither to be significant nor constitute any perceptible hazard, essentially in light of the small amounts of pigment used to prepare mortars.
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use of genie 2000 and excel vba to correct for γ ray interference in the determination of norm building material Activity Concentrations
Applied Radiation and Isotopes, 2018Co-Authors: J A Suareznavarro, M.m. Alonso, C. Gascó, Marcos Lanzón, Maria Teresa Blancovarela, Francisca PuertasAbstract:Abstract The γ-radiation emitted by building materials is calculated from the Activity indices for 232Th, 226Ra and 40K and expressed as the Activity Concentration Index (ACI). Gamma spectroscopy is a non-destructive technique frequently used to simultaneously determine the indices for several radionuclides. Spectral interpretation poses a number of challenges, including identification of γ-lines subject to summing-in effects, interference from other γ-ray emitting radionuclides and the time required to reach secular equilibrium. These challenges are not fully addressed by Canberra Industries’ Genie 2000, the software used by many laboratories to analyse samples. This article describes a Microsoft Excel workbook that exploits Genie 2000 flexibility to program applications with Visual Basic using Canberra's Nuclear Data Access Library and batch procedure tools. The workbook determines 40K Activity Concentration after correcting for 228Ac interference and 226Ra Activity directly from the γ-peak at 186.5 keV. The method proposed was tested by participating in 13 national and international scale inter-comparison exercises. The results were statistically indistinguishable from the reference values at a coverage factor of k = 3 and no statistically significant differences were identified between the respective means by a Student's t pairwise comparison.
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RadioActivity and Pb and Ni immobilization in SCM-bearing alkali-activated matrices
Construction and Building Materials, 2018Co-Authors: M.m. Alonso, C. Gascó, Anton Pasko, J.a. Suarez, Oleksandr Kovalchuk, Pavel V. Krivenko, Francisca PuertasAbstract:Abstract Partial or total replacement of Portland cement clinker by SCMs (Supplementary Cementitious Materials) is a priority for the cement industry in its pursuit of global sustainable development and eco-friendly binder manufacture. The most widely used SCMs include industrial by-products such as blast furnace slag, fly ash and red mud. Alkali-activated cements manufactured with SCMs may reduce the need for Portland clinker by up to 90 wt%–100 wt% with no significant decline in material strength. The trade-off, however, is the risk of higher than legally allowable levels of radioActivity and unbound heavy metals (Cd, Hg, Ni, Pb, Cr), which may leach into the soil with the concomitant adverse implications for human health and the environment. This study assessed the mechanical strength, leachability and natural radioActivity of alkali-activated cement paste containing industrial waste-based SCMs (blast furnace slag, fly ash and red mud) and Pb and Ni compounds. Strength was highest in alkali-activated slag and slag/fly ash pastes and lowest in the red mud-containing materials. The addition of Pb or Ni sulphates had no adverse effect on this parameter. Alkaline and OPC pastes showed a high level of immobilization of both lead and nickel ions. According to the radiological findings, the Activity Concentration Index ( I ) was higher in red mud than in OPC, blast furnace slag or fly ash. With ( I ) values lower than 1, however, all the hydrated/activated materials studied would be EU directive-compliant. Nonetheless, the use of these new materials will depend not only on the Activity Concentration Index, but also on their physical and chemical properties and the quality tests that must be passed to conform to legal requirements.
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Data on natural radionuclide's Activity Concentration of cement-based materials
Data in Brief, 1Co-Authors: M.m. Alonso, J. A. Suárez-navarro, R. Pérez-sanz, C. Gascó, A.m. Moreno De Los Reyes, Marcos Lanzón, María Teresa Blanco-varela, Francisca PuertasAbstract:Abstract Cement based materials may contain varying levels of radionuclides, mainly 226Ra (from the 238U series), 232Th and 40K, which are used to determine the Activity Concentration Index ("ACI"). According to the European directive Euratom 2013/59 in these materials, the “ACI” must be
