This publication examines the possible technological implications of retrievability when developing designs for geological nuclear waste repositories. Disposal strategies including scenarios for retrieving disposed nuclear waste have been driven by a desire to cope with or benefit from new technical advances in waste management and materials technologies, as well as changing social, economic and political conditions. In this respect, the publication analyses the concepts currently being developed by some countries for the retrieval of emplaced waste packages and any technological provisions that should be incorporated into the design, construction, operational and closure stages of the repository. It is targeted at those responsible for deep geological disposal programmes, including repository designers and decision makers.