Validation Study on Preliminary Evaluations of U-238 for JEFF

238 reaction cross sections in the resonance energy region under the JEFF project targeted to further consideration in both the Collaborative International Evaluated Library Organisation (CIELO) Pilot Project organized by the OECD/NEA and the Neutron Cross-Section Standards Project by the IAEA. The preliminary G-versions of U-238 evaluations have been validated through 94 criticality benchmark problems taken from the expanded criticality validation suite for MCNP. It was found that the G-versions 3 and 4 showed better performances than others by comparing the RMS errors and x² values relative to the benchmark keff values. In addition, the extension of the energy boundary between the RR and URR regions from 10 to 20 keV was considered to be efficient for all G-versions of U-238