Mayak
The Mayak Production Association (Russian: Производственное объединение «Маяк», from Маяк 'lighthouse') is one of the biggest nuclear facilities in the Russian Federation, housing plutonium production reactors and a reprocessing plant. The nuclear complex is located 150 km south-east of Ekaterinburg, between the towns of Kasli and Tatysh, and 72 km northwest of Chelyabinsk. The closest city, Ozyorsk, is the central administrative territorial district. As part of the Russian (formerly Soviet) nuclear weapons program, Mayak was formerly known as Chelyabinsk-40 and later as Chelyabinsk-65, referring to the postal codes of the site.