[en] The objectives of the research in the field of radiation protection research performed at the Belgian Nuclear Research Centre SCK-CEN are (1) to elaborate and to improve methods and guidelines for the evaluation of restoration options for radioactively contaminated sites; (2) to develop, test and improve biosphere models for the performance assessment of radioactive waste disposal in near-surface or geological repositories; (3) to asses the impact of releases from nuclear or industrial installations; (4) to increase capabilities in mapping and surveying sites possibly or likely contaminated with enhanced levels of natural radiation; (5) to identify non nuclear industries producing NORM waste, to make an inventory of occurring problems and to propose feasible solutions or actions when required; (6) to maintain the know-how of retrospective radon measurements in real conditions and to assess radon decay product exposure by combining these techniques. Main achievements in these areas for 2001 are summarised