[en] Seven critical experiments were performed on a horizontal split table machine using 4.48% enriched ²³⁵U uranium oxide (U₃O₈). The oxide was compacted to a density of 4.68 g/cm³ and placed in 152-mm cubical aluminum cans. Water was added to achieve an H/U atomic ratio of 2.03. Various arrays of oxide cans were distributed on each half of the split table and the separation between halves reduced until criticality occurred. The critical table separation varied from 4.3 mm to 29.3 mm. These experiments were performed in both plastic and concrete reflectors. The first five experiments required the addition of a high-enriched (approx. 93% ²³⁵U) metal driver to achieve criticality. Critical uranium driver masses ranged from 2.765 kg to 13.730 kg for 5 x 5 x 5 arrays of uranium oxide cans. In all five cases, the center can of the array was deleted to accommodate the driver. The uranium oxide mass was 1859.6 kg. Two additional experiments in the plastic reflector contained either 9.3-mm- or 24.3-mm-thick plastic moderator material between the oxide cans. These latter experiments did not require a driver to achieve criticality; and the uranium oxide mass was 723.9 kg for the configuration having the thinner interstitial moderator and 452.4 kg for the other