[en] Preclosure safety assessment for construction, operation, caretaking, and decommissioning is required by the US Nuclear Regulatory Commission (NC) regulations as part of a license application for nuclear waste repositories. This paper will present a variety of design and safety analysis issues addressed as part of the preclosure safety analysis of nuclear waste repositories. The definition of the issues and suggested approaches to resolving the issues will be presented. These technical issues arose during the process of defining site-specific issue resolution strategies related to design and preclosure safety (Key Issue 2) in the Office of Geologic Repositories Issues Hierarchy. These issue resolution strategies are described in the Basalt Waste Isolation Project (BWIP) Site Characterization Plan. Participation in the US Department of Energy (DOE) Preclosure Risk Assessment Methodology (PRAM) Working Group has also helped to define the open technical issues. 9 refs