An orphan Am-241 source, which was inadvertently included in scrap metal, was melted on September 21st, 2018 in a Finnish steel factory. The melting of the source was detected by the radiation pulse rate monitoring within the steelworks smelting process.
The activity of melted source can not be determined exactly. In the measurements the activity concentration (73 Bq/g) was at the same level as in the previous cases on July 26th, 2018 and on September 15th, 2018. It can be estimated that the activity of the melted source is 1110 MBq. The source is traced by the operator to stainless steel scrap delivered from Central Europe. Origin of the scrap metal is unknown.
Am-241 is captured in the dust suppression and filtration with other particulates in the dust phase and thus there were no environmental releases. In an Am-241 melt the steel remains uncontaminated. Nobody was exposed.
The factory has screening detectors of incoming scrap. Despite of the modern screening technology used, the source could pass through because of americium’s low gamma energy, which is easily attenuated by other scrap.
Event date: Fri, 21-09-2018