Japan has restarted on Sunday the first of its more than 50 suspended nuclear power plants in Oi, western Japan, a year after the Fukushima nuclear disaster and two months of totally no nuclear power generation.

The No. 3 reactor operated by Kansai Electric Power Co. (Kepco) restarted amid widespread and strong public opposition. However, actual supply of electricity to target consumers will only be realised until Wednesday.

The 1,180-megawatt reactor will be fully operational by end of the week, Kepco said.

In June, Japanese Prime Minister Yoshihiko Noda ordered the restart of the suspended power reactors, claiming the use of nuclear power as the country's main energy supply was vital for its economy to move and grow.

Japan's more than 50 working nuclear reactors were ordered suspended one at a time for safety checks after the Fukushima Daiichi plant nuclear disaster in 2011. The accident, triggered by the devastating earthquake and tsunami that hit the country in March 2011, contaminated a large part of northern Japan with radiation and forced the evacuation of more than 100,000 individuals.

Two days before the restart of the nuclear power plant in Oi, protesters, estimated at 200,000, according to BBC News, participated in anti-nuclear rallies in the country's capital.

Prior to the nuclear meltdown accident, Japan depended on its 54 reactors for about one-third of its energy.