The decommissioning of nuclear installations generates large amounts of several types of material streams. Depending on their radionuclide composition and activity concentrations, some of the materials can be recycled in the conventional industry or in the nuclear industry, while other material streams will be considered as radioactive waste to be disposed of in specific designed final repositories. During the decommissioning of Belgian Reactor 3 (BR3), a huge amount of radiological data is being produced and managed with the main goal to fulfil the acceptance criteria for the targeted destinations. On the other hand, the immense data availability could represent a valuable source for data mining. Unfortunately, the available data is not always sufficiently organised for direct use.