This guidance document sets forth means, methods and procedures that the staff of the U.S. Nuclear Regulatory Commission (NRC) considers acceptable for satisfying the requirements for the physical protection of spent nuclear fuel (SNF) during transportation by road, rail and water, and for satisfying the requirements for background investigations of individuals granted unescorted access to SNF during transportation. Chapter 1 discusses the regulatory basis and definitions applicable to shipments of SNF. Chapter 2 corresponds to the general requirements for the physical protection of SNF while in transit. These requirements apply to all SNF shipments regardless of the mode of transportation used for a particular shipment. Chapters 3, 4, and 5 discuss additional requirements specific to each particular transport mode-road, rail, or U.S. waters. Chapter 6 discusses the requirements for background investigations of individuals with unescorted access to SNF in transit.