This presentation highlights the last reflections of the author on NWM in Belgium. It focuses on the new governance practices in Belgian nuclear waste management (NWM) from its ‘participatory turn’ in the late 1990s. Rather than praising (or rejecting) participation versus expert analysis, we make use of a theoretical and analytical framework in which the important dynamics for the analysis are ‘opening up’ and ‘closing down’ technological appraisals and commitments. Even though NWM agencies often plea for an integrative approach between experts analysis and participation, in practice this reveals itself rather complicated as both exercises are often kept separate. We address this separation and its consequences and we find that societal concerns remain subsumed in the technical options which have long been favoured by the Belgian agency. This taming of uncertainty may come at a high price, if it systematically reduces the scope of alternative options for governance intervention or if societal consultations ultimately appear like an instrument of legitimation of already-taken decisions.