The TVEL Fuel Company (TVEL) is a Russian nuclear fuel cycle company headquartered in Moscow. It works mainly in uranium mining and the production of nuclear fuel. TVEL belongs to the Atomenergoprom holding company (part of Rosatom). TVEL supplies fuel to the Czech Republic, Slovakia, Bulgaria, Hungary, Ukraine, Armenia, Lithuania, Finland, China and India. In the world, 73 power reactors (17% of the world market by number) and 30 research reactors are currently running with TVEL made fuel. TVEL is developing the TVS-K fuel assembly for Western-designed reactors. As of 2017 TVS-K is in pilot usage, and TVEL hopes it will be ready for commercial supply in 2021