[en] The activation aspects of pure fusion and hybrid fusion technology is studied to assess the radioactive safety of various fusion concepts including tokamak pure fusion, fissile fuel producing hybrid and radio waste transmuting hybrid. The activation properties of breeding, coolant and structural materials in fusion reactors might be quite different from those in fission reactors because of the high energy D-T fusion neutrons from the fusion cores. A study on the involved activation reactions and the uncertainties of the associated nuclear cross-sections is carried. The activation properties of various first wall concepts and blanket concepts are discussed. The radioactive inventory during the operation lifetime and the potential hazard of the radioactive nuclides with respect to near term (reprocessing) and long term (waste disposal) aspects are calculated, with reference to ITER/NET (International Thermonuclear Experiment Reactor/Next European Torus), STARFIRE (a commercial tokamak fusion power reactor), HEHR (Hefei Experiment Hybrid Reactor), HCHR (Hefei Commercial Hybrid Reactor) and THWT (Tokamak Hybrid Waste Transmuter), using the improved general one-dimensional multi-group radioactivity calculation code FDKR as well as the improved decay chain data library AF-DCDLIB. Also, a comparison among various conceptual fusion reactors, hybrid reactors and fission reactors including LWR (Light Water Reactor), HTGR (High Temperature Gas Reactor) and FBR (Fast Neutron Breeding Reactor) is carried out