This report documents the first phase of a multi-year project to understand the technical feasibility and logistical implications of direct disposal of spent nuclear fuel (SNF) in existing dual-purpose canisters (DPCs) and other types of storage casks. The first phase includes a set of preliminary disposal concepts and associated technical analyses, identification of additional R&D needs, and a recommendation to proceed with the next phase of the evaluation effort. Preliminary analyses indicate that DPC direct disposal could be technically feasible, at least for certain disposal concepts. DPC disposal concepts include the salt concept, and emplacement in hard rock (i.e., crystalline) or argillaceous sedimentary rock, with or without backfill, and others. The report also covers a range of behaviors potentially important to DPC direct disposal including thermal response, postclosure nuclear criticality, and long-term opening stability. Important factors that help to ensure postclosure safety for DPC direct disposal are examined as are thermal management of the waste, criticality, and operational and logistical issues to be considered in DPC disposal options. The means to focus future work is also presented.