Japan restarted on Tuesday its first nuclear reactor since the Fukushima disaster, which took place in 2011.

All nuclear power plants in Japan were gradually turned off after a series of meltdowns at Fukushima caused by the powerful earthquake and resulting tsunami in 2011.

After passing new strict safety tests, Kyushu Electric Power restarted reactor No.1 at Sendai Nuclear Power Plant (NPP).

However there is huge public concern surrounding the return to nuclear power, the BBC reports

There are protests both outside Sendai NPP and the residence of Japanese Prime Minister Shinzo Abe in Tokyo.

A total of 25 plants have applied for restart, but all are facing legal challenges from local residents.

It will take about 24 hours before a full reaction takes place and the plant is expected to start generating power by Friday, reaching full capacity next month.

Abe assured on Monday that the reactor has passed the “world's toughest safety screening”.

Since turning off all nuclear plants, Japan has been relying on importing fossil fuels, which has turned out to be expensive for the country.

The government insisted on resuming nuclear power in order to cut import expenses and CO2 emissions.

A second reactor at Sendai is scheduled for restart in October.

Although more than USD 100 M were spent on fitting new safety systems, local residents do not consider the new measures as stringent enough.

The earthquake and tsunami claimed the lives of almost 16 000 people and more than 2500 are still missing.

None of the deaths were related to the nuclear disaster.

The damage of Fukushima NPP caused the evacuation of 160 000 people from the surrounding areas and continuing high radiation levels make their return impossible.