Processes of verification and calibration of portal monitors for the detection of radioactive sources in metal scrap

In Spain a large number of systems are installed for the detection of radioactive sources at the entrances of metal recycling facilities (scrap yards, steelyards and smelting installations).This equipment is subject to operational controls that depend on the facilities at which it is installed. No homogeneous criteria existing in Spain for the verification of its correct operation and sensitivity. A project has been undertaken to harmonize the operating parameters of the portal monitors installed. This project has been carried out by Enresa (the Spanish radioactive waste management agency) and the Nuclear Safety Council (CSN, Spanish regulatory authority) in collaboration with the Polytechnic University of Madrid. A series of tests and checks have been carried out on the portal monitors of several facilities. This has allowed verification and calibration procedures to be drawn up for this type of detection equipment, with recommendations regarding the frequency with which these processes should be performed. Presented hereby are the protocols developed for the verification and calibration of this equipment, along with the results obtained from the tests performed on various portal monitors installed in Spain. (author)