Every year millions tons of steel are produced worldwide from recycled scrap loads.Although the detection systems in the steelworks prevent most orphan radioactive sourcesfrom entering the furnace, there is still the possibility of accidentally melting aradioactive source. The MetroMetal project, carried out in the frame of the EuropeanMetrology Research Programme (EMRP), addresses this problem by studying the existingmeasurement systems, developing sets of reference sources in various matrices (cast steel,slag, fume dust) and proposing new detection instruments. This paper presents the keylines of the project and describes the preparation of radioactive sources as well as theintercomparison exercises used to test the calibration and correction methods proposedwithin the project.
