Naturally-Occurring Radioactive Materials (NORM)

The main issue in view of NORM-impacted sites 1 is how such sites, e.g. radium contaminated sites, uranium liabilities, sites exploited for the mining of metals associated with NORM and wastes arising from industries processing or generating other kinds of NORM, are assessed and regulated. In view of the implementation of the new Basic Safety Standards (BSS), the regulations apply to the management and clean-up of existing sites as well as to the licensing of future discharges and large quantities of NORM waste. This necessitates a better understanding of key routes involved in the migration and bioavailability of radionuclides at NORM sites, i.e. to develop (i) sampling strategies to characterize NORM-contaminated sites, (ii) the practical use of hydrogeological and hydrogeochemical mechanistic modelling together with a process-based understanding of radionuclide migration in abiotic and biologically influenced environments, radionuclide transfer into biota and finally into the human food chain, and (iii) projective modelling for existing sites as well as generic modelling for licensing procedures on timescales from years to millennia. Research in these directions will foster science based advice on the classification of NORM and NORM affected sites according to the recommendation and requirements set in the BSS and on the opportunity to undertake innovative and long-term effective remediation actions. It will also support the development of advanced generic radioecological models with a lower degree of conservatism, thus avoiding unnecessary restrictions in licensing procedures. Due to the complexity of NORM sites, which are characterized, for instance, by complex mixtures of different chemicals and minerals as well as disequilibria in radionuclide decay chains, challenges arise not only from the lack of comprehensive scientific data, but also from existing model concepts themselves, which do not adequately describe the interplay between simultaneously occurring processes at a NORM site. Therefore, a promising strategy is to reduce modelling uncertainties by identifying and parametrizing the key processes that influence the radionuclide behaviour and to transfer this knowledge into a mechanistic model sufficiently complex to describe the radionuclide behaviour in the environment, however, simultaneously simple enough to be practical and applicable to different NORM sites. In view of potential hazards associated with the radioactive source term of NORM sites related to former, current or future human activities, as well as the need for developing preventive methods at different stages of a technological process in a NORM industry, this is an important task.