In this study, experimental neutron-emission spectra produced by (n, xn) reactions on nuclei Th-232 have been compared with experimental U-238(n, xn) neutron-emission spectra from 2 to 18 MeV. Angle-integrated cross-sections in neutron induced reactions on targets U-238 have been calculated at the bombarding energies from 2 to 18 MeV. In the calculations, the geometry dependent hybrid model and the cascade exciton model including the effects of pre-equilibrium have been used. In addition, we have described how multiple pre-equilibrium emissions can be included in the Feshbach-Kerman-Koonin (FKK) fully quantum-mechanical theory. By analyzing (n, xn) reaction on U-238 with the incident energy from 2 to 18 MeV, the importance of multiple pre-equilibrium emission can be seen clearly. All A calculated results have been compared with experimental data. The obtained results have been discussed and compared with the available experimental data and found agreement with each other. (c) 2005 Elsevier Ltd. All rights reserved.