TVEL OJSC (100% subsidiary of Atomenergoprom OJSC) is a producer and supplier of nuclear fuel for commercial and research reactors in Russia and abroad.

Presently, the basic reactor technologies used in the field of nuclear power engineering is pressurized water reactors (WWER (VVER) in Russia and PWR and BWR in the West). 86% of all reactors are based on this technology. The reactors of Russian design use hexagonal fuel assemblies while PWRs – square assemblies.