Japan Reactor on Grid in 1st Post-Tsunami Restart A nuclear reactor in western Japan has begun generating electricity in the first restart since last year's tsunami led to a nationwide nuclear power plant shutdown. The No. 3 reactor at the Ohi nuclear plant went back on the grid Thursday morning, according to the plant's operator. Ohi is the first reactor to be restarted since last year's earthquake and tsunami caused meltdowns and massive radiation leaks at the Fukushima Dai-ichi plant north of Tokyo. Japan's other reactors were gradually taken offline for maintenance or safety checks, and the country had been without nuclear power since May. Public opposition to restarting reactors is high because of safety issues raised by the Fukushima disaster. But officials say the country needs nuclear power to avoid power shortages in the high-demand summer months.