[en] Preliminary performance requirements and criteria for the sealing of shafts, tunnels, and boreholes in a nuclear waste repository in basalt are presented in this document. These performance requirements are derived from the regulations drafted by the US Environmental Protection Agency, the US Nuclear Regulatory Commission, the National Waste Terminal Storage Program Criteria for Mined Geologic Disposal of Nuclear Waste, and the Basalt Waste Isolation Project Principal Criteria Document. The preliminary performance requirements and criteria presented in this report will be used to develop a repository seal system conceptual design. As additional data are obtained the preliminary performance requirements and criteria contained in this document will be reviewed for their adequacy. 50 refs