This report describes various national spent fuel conditioning concepts, the current state of technology, the waste package designs so far developed, and the engineering operations required for their manufacture. It supplements IAEA Technical Reports Series No. 320, Evaluation of Spent Fuel as a Final Waste Form. Contents: 1. Introduction; 2. Major factors in the development of conditioning concepts; 3. Waste package design; 4. Preconditioning processes; 5. Conditioning processes; 6. Summary; Appendix: National spent fuel conditioning concepts.