The operator of a nuclear power plant in Miyagi Prefecture, northeastern Japan, is set to restart one of its reactors on Tuesday -- more than 13 years after it suffered damage in the 2011 earthquake and tsunami disaster.

The utility took anti-disaster steps, including raising the plant's seawalls to 29 meters above sea level. The 2011 disaster cut the No. 2 reactor off from many of its external power sources and left its underground facility inundated. The No. 2 unit passed a Nuclear Regulation Authority screening in 2020.

The operator of the Onagawa plant, Tohoku Electric Power Company, plans to begin removing control rods on Tuesday night to activate the reactor.

Tohoku Electric expects the reactor to reach a self-sustaining chain reaction at around midnight. Officials say power generation will likely start in early November.

This is the same type of reactor as the crippled ones at the Fukushima Daiichi nuclear plant. Onagawa's boiling-water type will be the first reactor to restart in the areas hit by the 2011 disaster.