Russian state nuclear firm Rosatom and the Atomic Energy Organization of Iran (AEOI) have started work on the first of two new nuclear power plants to be built at Bushehr, alongside the controversial existing reactor.

The Bushehr-2 and Bushehr-3 plants will each have 1GW generating capacity, and are scheduled to be brought online in 2023 and 2025, under an agreement signed by Rosatom and AEOI in November 2014.

The agreement envisages a total of four new reactors being built at Bushehr, as...