[en] Four H₂O-moderated, slightly-enriched-uranium critical experiments were analyzed by Monte Carlo methods with ENDF/B-IV data. These were simple metal-rod lattices comprising Cross Section Evaluation Working Group thermal reactor benchmarks TRX-1 through TRX-4. Generally good agreement with experiment was obtained for calculated integral parameters: the epi-thermal/thermal ratio of U238 capture (rho²⁸) and of U235 fission (delta²⁵), the ratio of U238 capture to U235 fission (CR*), and the ratio of U238 fission to U235 fission (delta²⁸). Full-core Monte Carlo calculations for two lattices showed good agreement with cell Monte Carlo-plus-multigroup P/sub l/ leakage corrections. Newly measured parameters for the low energy resonances of U238 significantly improved rho²⁸. In comparison with other CSEWG analyses, the strong correlation between K/sub eff/ and rho²⁸ suggests that U238 resonance capture is the major problem encountered in analyzing these lattices