Background: The energy spectrum of water-cooled fusion-driven subcritical system is very complex. It contains large numbers of high-energy neutrons and thermal neutrons. Therefore

conventional database of fission reactors or fast reactors is not appropriate. Purpose: In order to improve the accuracy of the neutronics analysis for subcritical systems with moderated water-cooled blanket

nuclear cross-section data for thermal scattering was developed based on HENDL3.0/FG fine group. Moreover

a conceptual design of fusion-fission hybrid reactor for energy production

named FDS-EM

was tested and analyzed using the database. Methods: The THERMR module of the general application database processing program NJOY was used in developing the library. Critical safety benchmark testing had been carried out to test the reliability of the library. Results: The effectiveness of the nuclear database was validated by the benchmark testing. The influence of thermal up-scatter on keff

TBR and neutron flux was predicted and verified in theoretical and calculational perspectives. Conclusion: The up-scatter effect is essential in water-cooled fusion-driven subcritical system and this database could be used in the design of future fusion-driven subcritical system. Abstract