The main objective of this study is to compare the effect of the natural lithium and lithium with different enrichments between 10% and 90% on neutronic parameters; such as tritium breeding ratio (TBR), displacement per atom (DPA) and gas production using the different data libraries (ENDF/B.V, ENDF/B.VI and CLAW IV). Therefore, the natural lithium and different enrichment lithium were used as a moderator in an experimental hybrid reactor for the calculation of the nuclear parameters. Neutronic calculations were performed by recent Monte Carlo Neutron-Particle Transport code MCNP5 version 1.40 for a 14.1 MeV (D, T) fusion driver under a neutron wall load of 2.25 MW/m(2) (10(14) n/s). TBR values in the blanket for all investigated cases were obtained greater than the minimum requirement (TBR > 1.05). Considering radiation damage limits (100 DPA and 500 appm/FPY) for structural materials, the FW replacement will be needed every 2.1 and 3.5 years for DPA and He-production, respectively. (C) 2007 Elsevier Ltd. All rights reserved.