TOKYO – Protesters this weekend thronged the wide streets in front of the prime minister’s office in Tokyo, and across the country they gathered about a quarter-mile from the entrance of a nuclear plant.

They shouted “No to the restart” and parked cars in front of the plant’s access road, blocking workers from coming or going, according to Japanese media.

But the workers were already inside. Sunday, at the Ohi nuclear facility along Japan’s western shoreline, those workers went through the technical steps to reboot a reactor, the first to come back online since last year’s massive nuclear accident at Fukushima Daiichi.

The restart at Ohi – with potentially more to follow – will avert dire power shortages and sustain the economy, Prime Minister Yoshihiko Noda has told the nation. But the restart also has divided the country, staging an increasingly hostile showdown between the government and those doubtful about its atomic safety claims.

Some political experts thought Noda’s announcement two weeks ago about the restart of two reactors at Ohi – the No. 4 unit is scheduled to restart this month – would quiet public opposition. Instead, Noda’s announcement fomented it, and social media-organized protests that once drew hundreds now draw thousands. A Friday rally in front of Noda’s office drew 17,000, according to police, although organizers put the number around 200,000.

The central government has so far given no indication that the public display will cause a rethink of its nuclear restart efforts. Wide-scale protests are rare in this country, where people traditionally comply with authority figures, and Noda, who is also pushing for a consumption tax increase, faces a backlash for his pro-nuclear stance.

Engineers at Ohi planned to pull out the control rods that prevent nuclear fission on Sunday. By Wednesday, according to Japan’s Kyodo news agency, the 1,180-megawatt reactor will begin transmitting power.