[en] Conceptual designs of spent-fuel shipping casks for use by facilities participating in the Breeder Reactor Program have been developed by Sandia Laboratories, Albuquerque, New Mexico. Some aspects of conceptual designs that are reviewed are interface requirements and cask design features. The major emphasis of the work to date has been to develop cask designs which would be suitable for use at the Fast Flux Test Facility (FFTF) and the Clinch River Breeder Reactor Plant (CRBRP). However, the advanced technology utilized in developing spent-fuel shipping-cask designs for these facilities results in many cask features which would be required by all breeder reactor plants