site of a uranium enrichment pilot plant in Gauteng province, South Africa, on the western outskirts of Pretoria. Built by the Uranium Enrichment Corporation of South Africa (Ucor), it became operational in 1975. Valindaba uses a process, developed in the 1960s by scientists in the Republic of South Africa, for the enrichment of uranium in the fissionable 235-isotope. The feed material required by the plant is uranium in the form of uranium hexafluoride (UF₆). It was decided to enlarge the plant in 1978 in order to produce enough enriched uranium to meet the needs of the two Koeberg nuclear reactors near Cape Town.