Iranian Foreign Minister Ali-Akbar Salehi said the the plant has reached its criticality stage or fission process statge, which allows the atoms to split by themselves in a chain reaction without interference from operators.

The fission process lasts for about two months after which the plant is expected to gain about 40% of its power, reports Xinhua.

The Russian-built Bushehr plant will use the nuclear fuel supplied by Russia and is expected to generate about 1,000MW of electricity, about 2.5% of Iran’s electricity usage.

The Chief of Atomic Energy Organization of Iranian said the Bushehr nuclear power plant would soon join the national grid.