Oklo is a region near Franceville in the Haut-Ogooué province of Gabon. Several natural nuclear fission reactors were discovered in the uranium mines in the region in 1972.
The nuclear reactor startup OKLO is working with Idaho National Lab to get its liquid metal-cooled fast reactor design (AURORA, 15MWe) up and running by 2027 which Open AI CEO Sam Altman intends to use for his company's power source. Details here.
They also have a different business model.