Safety in Long Term Radioactive Waste Management: Insight and Oversight

High-level, long-lived radioactive waste remains hazardous for periods that go well beyond
our human conception of time (many thousands of years). Because active safety measures
are considered unreliable, unjustifiable and simply impossible over such long time spans,
experts worldwide recommend geological disposal as the preferred strategy for long-term
radioactive waste management, to a large extent due to its promise of delivering ‘passive
safety’. Passive safety refers to the repository being safe ‘by itself’, i.e. unmediated by
human actors and actions. Safety is thus approached technically and delineated as an
intrinsic property of the disposal system. As such, the notion of 'passive safety' entails a
system simplification that allows for approaching safety in a more calculable and predictable
manner than would be the case for 'active safety'. In this article, we describe and analyze the
ambiguity of this seemingly straightforward approach to safety. Drawing on constructivist
insights from safety science and science and technology studies, we propose a more
integrated sociotechnical vision that transcends the active versus passive safety division. The
notion of 'oversight', as it is currently starting to surface in international radioactive waste
management discourses, will be used as a sensitizing concept, offering potential to elaborate
such an integrated vision.