Working Group 4

WG 4: Improving radiological impact assessment models for the reuse of NORM residues in building materials. Investigating the influence of different legislative radioprotection scenarios on the use of NORM residues in building materials and the related impact on both gamma exposure and indoor air quality.

Sub-task 4.1 To investigate available impact assessment models for the use of NORM in building materials specifically for the cement, concrete and ceramics industries.

Various factors complicate the radiological impact assessment of building materials containing NORM residues: (1) Lack of secular equilibrium among natural radionuclides from decay series or state of transient equilibrium only is very common among NORM residues originating from different industrial processes. Therefore additional information is required on the changes of natural radionuclides composition and activity concentration in building materials made from NORM residues in the course of time and their effect on usefulness of particular NORM residues. (2)

Radon exhalation is a key process influencing quality of the construction materials. (3) The radiation attenuation factor for different kind of construction materials is a key parameter for modelling of exposure to external radiation inside. In addition when modelling the indoor air quality the co-existence of radiological and toxic substances, such as by example heavy metals, needs to be considered.

WG 4 will target challenges in modelling and modelling tools specifically for scenarios using the newly developed construction materials containing NORM residues. Research on several computational methodologies – room models [Markkanen, 1995] – and in situ techniques [Nuccetelli et al., 2001; Bochicchio et al., 2004; Risica et al, 2001] is available to evaluate and predict the indoor gamma dose rate and the radon and thoron indoor concentration on the basis of the radioactivity content and other characteristics of newly developed building materials. It was found that modelling of doses due to natural radionuclides in building materials is an effective tool for optimization of radiation protection. Such modelling cannot be done for each building material, however in case the activity index is higher than 1, the modelling might be helpful in deciding if the construction materials under consideration might be used.

Deliverables: improved radiological impact models based on optimized scenarios for the use of NORM in building materials specifically for the (i) cement, (ii) concrete and (iii) ceramics industries and (iv) specifically for the use of geopolymers.

Sub-task 4.2 End-of-life considerations for building materials with NORM.

Building materials can be recycled in other applications or building materials. It is the scope of this sub-task to investigate if the building materials with NORM lead in the long-run to un-safe building materials. The work performed herein will analyse the different scenarios and in collaboration with WG 1 and WG 2 define the recycling potential. Dilling et. al [2009] investigate the release of natural radionuclides, the leach ability, from NORM residues caused by sewage basing. The leach ability of building materials containing NORM residueswill be as well in the focus of WG 4. This topic will be discussed in close cooperation of WG 1 and WG 2.

Deliverables: Report on End-of-Life considerations for building materials with a particular focus on the leach ability of “NORM-building materials”. Information on the leach ability will be included in the database.

Sub-task 4.3: In close collaboration with legislative experts, researchers and experts from industry the possibilities and the practical implementation of the newly developed building materials to the market will be evaluated.

WG 4 will organize open discussions with all stakeholders in order to establish their interest on this matter and in order to understand existing practical problems that the implementation of the newly developed building materials will effectively face. In this step of the evaluation the Advisory Board will be involved. Evaluation of practices will take into account the radiological impact models,

input from WG 1,2 and 3, current European legislation, the new EU-BSS and experiences from current practices.

Deliverables: (i) Round table discussions with all stakeholders and (ii) reports on the evaluation of the practical implementation of the newly developed building materials on the market.

Sub-task 4.4: The goal is to investigate and propose alternative legislative scenarios that can potentially stimulate the use of NORM residues in European cement, concrete and ceramics industry while assuring protecting of the population.

Deliverables: Reports for the (i) European cement, (ii) concrete and (iii) ceramics industry and (iv) on the use of geopolymers. with the comparison and evaluation of alternative legislative scenarios that can potentially stimulate the use of NORM residues while limiting the radiological impact. The output of WG 4 can lead to a reassessment and readjustment of the criteria used for the critical evaluation of existing and emerging residues in building materials (WG 1).