Sensitivity tests and risk evaluation for steelworks portal systems

Fourteen portal systems installed at the entrance of as many iron scrap recycling plants have been tested. The systems which underwent the test were supplied by three manufacturers: Bicron, Eberline and Exploranium. For the tests, a truck trailer loaded with iron scrap was equipped with guide tubes for the introduction of radioactive sources. During the whole experimental campaign, the truck trailer was not modified, to assure test reproducibility. Analyzing the collected data, it was determined the lowest exposure intensity in air from a 137Cs source still able to cause an alarm when, centered in the load, passes through any portal. On the basis of this value it follows a risk evaluation for a steelworks equipped (in agreement with the rules of Lombardia region) with a portal at the entrance, area monitors for critical sites and gamma spectrometer for steel specimen.