The nuclear accident of the installation took place on September 30, 1999, in the nuclear plant conversion building.. It is currently owned by the company JCO. The Japanese town of Tokaimura was the scene of the world's worst nuclear accident since the 1986 Chernobyl reactor explosion. The uranium fuel treatment facility is located, in Tokaimura (Japan), 120km northeast of Tokyo, in the Ibaraki Preface. The installation consists of three auxiliary uranium conversion buildings: