Discovered radioactive source in a railway wagon, loaded with scrap metal, in Stomana Industry” S.A.

Site with SIR or place of the event: “Stomana Industry” S.A, Pernik

Event description:

During the entrance check of a scrap-loaded railway wagon in “Stomana Industry” S.A. (town of Pernik) a source, containing Ra-226, representing control device with a luminous dial, has been discovered.

The NRA emergency centre was notified that on 17^th July 2010 the portal radiation monitoring system of the “Stomana Industry” S.A. – town of Pernik detected elevated radiation level in a scrap-loaded railway wagon. The railway wagon has been stationed on a separate track on a special platform on site and has been put under surveillance.

The measurements have shown slightly elevated radiation levels, up to 1.1 µSv/h, on the surface of a small area on the top of the wagon. As a reference, the values of the natural gamma background in the area of Pernik are between 0.07 and 0.11 µSv/h. Following a field spectrometric analysis, the presence of the radioactive isotope Ra-226 (radium-226) has been identified.

The wagon has been partly unloaded. The detail, causing the elevated radiation levels, has been discovered and removed from the scrap. The later represented control device with a luminous dial (Φ 8 cm, length 10 cm and weight about 150 g). The measured values of the gamma dose rate at 1 m have been about 0.24 µSv/h and in contact – up to 15.1 µSv/h. The isotope Ra-226 has been included as an ingredient of a luminous paint.

The source has been packed and put in a safe place for temporary safe storage. After additional measurements the railway wagon has been released for unloading.