Atomstroyexport, Russia's nuclear power equipment and service export monopoly, has been building two reactors for the Kudankulam plant in the southern province of Tamil Nadu since 2002 in line with a 1988 deal between India and the Soviet Union.
In February this year Russia and India initialed a new agreement to construct four more reactors for the Kudankulam plant.
Russia is obliged to supply nuclear fuel for the reactors and re-export the spent fuel.
Last year Russia proposed that India invest in the construction of a uranium enrichment center in Angarsk, east Siberia.
The nuclear center, part of Moscow's non-proliferation initiative to create a network of enrichment centers under the supervision of the International Atomic Energy Agency, will be based at a chemical plant in Angarsk. The center, co-founded by Russia and Kazakhstan, will also be responsible for the disposal of nuclear waste.