Lessons learnt from storage practices for residues from radium production: A re-evaluation of the Olen site (Belgium)

From the early 20's to the mid 70's the industrial activities of Metallurgie Hoboken-Overpelt (MHO) at Olen, now Union Miniere, were known world wide for the radium production. During several decades, MHO was one of the most important radium production plants and contributed significantly to the widespread use of radium in medical and industrial applications. For the production of radium large amounts of high grade uranium and radium ores were imported from mines in Katanga (former Belgian Congo). These ores were extremely rich in uranium (uraninite) and associated minerals such as Co-Ni-sulfides, lead- and molybdenum minerals, among many others. Remains of the processed ores and the production were stored at the industrial plant at Olen, together with some radioactive wastes from dismantling and decontamination of production facilities. Disposal of such waste types requires specific measures to guarantee long-term containment of the waste of which some components such as long-lived radionuclides and heavy metals may remain indefinitely. In Olen these wastes are present in a surface repository which was built in the mid 50's and heavily re-engineered and remediated in the mid 80's. This paper documents a recent performance assessment (PA) study carried out to investigate the long-term radiological consequences resulting from the surface storage facility