Whether Japan will suffer a sharp power crunch is still unclear.
Electricity shortages are expected only at peak periods, such as the middle of the day in hot weather, and critics of nuclear power say proponents are exaggerating the consequences to win public approval to restart reactors.
Hokkaido Electric Power Co. spokesman Hisatoshi Kibayashi said the shutdown was completed late Saturday.
The Hokkaido Tomari plant has three reactors, but the other two had been halted earlier. Before March 11 last year, the nation had 54 nuclear reactors, but four of the six reactors at Fukushima Dai-ichi are being decommissioned because of the disaster.
Yoko Kataoka, a retired baker who was dancing to the music at the rally waving a small paper carp, said she was happy the reactor was being turned off.
"Let's leave an Earth where our children and grandchildren can all play without worries," she said, wearing a shirt that had, "No thank you, nukes," handwritten on the back.
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