AbstractCalculations and analyses on the transmutation of long-lived actinide 237Np radioactive waste with a fusion-fission hybrid reactor are reported. A new waste management concept of burning HLW (high-level waste), utilizing the released energy and converting 237Np into 239Pu fissile fuel through transmutation has been adopted. Time-dependent depletion calculations were performed using a modified version of the BISON 1.5 one-dimensional neutron transport and burn-up calculation code system. The transmutation rate of 237Np and its relationship to neutron wall loading and Pu and Np concentrations in the transmutation zone were explored; relevant results are given.