Outokumpu Reports Radiation Incident at Tornio Site
02/27/2012 - Outokumpu's Tornio melting furnace was recently exposed to a source of radiation that has since been identified as americium. Four meltshop employees were exposed to radiation as they entered the melting furnace during maintenance work.
Outokumpu's Tornio melting furnace was recently exposed to a source of radiation that has since been identified as americium. The company says that the mill security system revealed the radiation source and standard security actions were carried out according to procedure. Four meltshop employees were exposed to radiation as they entered the melting furnace during maintenance work.
Finnish Radiation and Nuclear Safety Authority (STUK) commented on the incident: "Preliminary measurements made by STUK indicate that one of the employees was potentially exposed to a dose of approximately ten millisieverts of radiation. The dose was limited and does not pose adverse health effects to the employee. According to the seven-step International Nuclear Event Scale (INES), such a dose is a level 2 incident, meaning that it is a material safety risk event. The first measurements of the three other employees observed no abnormal radioactivity. This incident didn't pose any hazard to employees outside the meltshop furnace area.
“The measured radiation dose of this incident can be compared to standard radiation dose guidelines set for workers engaged in radiation fields. According to the guidelines, the average radiation dose limit is 20 millisieverts per annum over a five-year period and the annual maximum dose must not exceed 50 millisieverts in any given year.
“The radioactive material was identified to be the isotope americium 241. Americium 241 is for example used in industrial measurement devices that require high sensitivity."
Outokumpu notes that its supplier contracts for recycled steel clearly stipulate that the material must not contain any radiating elements; however, americium ended up in the melting process through recycled steel in this case.
Outokumpu is conducting radiation measurements at the Tornio site to ensure that the smelter has no harmful amounts of radioactive materials. Samples at the meltshop will be taken and sent to the STUK Radiation Laboratory for analysis.
As a standard procedure, Outokumpu conducts radiation measurements in various stages of the production process to ensure that no radiating materials end up in the process. Measurement devices containing americium may enter the melting process, the company explained, as the sealed radiation sources cannot be detected with radiation detectors until the shield of the radiation source breaks down in the melting process.
Outokumpu is a global leader in stainless steel with customers in a range of industries. The company employs about 8000 people in more than 30 countries. The Group’s head office is located in Espoo, Finland.
