The radioactive sources treated as scrap: regulatory actions

Control loss of a radioactive source may result in a radiological emergency, especially if the source is treated as scrap. Incidents or accidents have been registered all around the world, and many of them, as a result of orphan sealed radioactive sources, lead to situations of radiological risk. This paper presents one case registered in Argentina when a portal radiation monitor detected a radioactive source of Kr-85 that had been used in a nuclear gauge for thickness measurement. The source, unlabelled and unidentified, was detected by the monitor installed in an important steel mill inside the scrap that was going to be processed. An operator of the portal reported this event to the Nuclear Regulatory Authority (ARN), through the Radiological Emergency Intervention System (SIER), whose personnel kept the source under control. This is the reason why the ARN carried out an investigation to determine the origin of the source and, at the same time, identified, in ARN laboratories, the radioactive material of the source. This led to a company that had gone bankrupt and had not reported this situation to the ARN. According to ARN records this facility owned eleven additional sources of similar characteristic. These sources were found in different locations, some of which were several kilometers away from the place where they were authorized to be used. At the end, after important efforts, all the sources were found and stored in an authorized repository. All steps that have taken place to keep the radioactive material under control as well as a detailed description of the situation and the recommendations applied are presented in this paper. (author)