Lessons learnt from an accidental release of 45 GBq 131I in Fleurus, Belgium

On August 22, 2008, a cloud of 131I was released from the Institut des Radioelements (IRE), a producer of medical isotopes located in Fleurus, Belgium. The peak of the release took place in the weekend of 23-24 August and was followed by a smaller, continuous release which lasted for several weeks. Several measures were taken after notification of the release to the Federal Agency of Nuclear Control, the Belgian nuclear safety authority. The nuclear emergency plan was activated on a N2 level. Under this emergency plan many environmental samples were taken and analysed with the purpose of verifying whether there was no risk for the population to obtain a significant dose via the food chain. Air samples were taken to confirm that no significant persistent release of 131I was still occuring. This air monitoring was performed just after notification of the release and during major replacement work of the filter systems of the isotope production plant. The Belgian Nuclear Research Centre SCK•CEN collected and analysed many of the environmental samples, performed the air monitoring and participated in the evaluation cell of the National Crisis Centre.