Chubu Electric Power Company has restarted Hamaoka 3 for the first time since an earthquake of magnitude 7.1 struck near the plant in August. The reactor will not reach full power and enter commercial operation for some time while power levels are slowly increased and final operational checks are carried out. Hamaoka 3 was shut down for regular maintenance work when the earthquake struck. Although there was no notable damage to any of the five reactors at the power plant, Japanese nuclear operators work within strict regulations tightened significantly after a July 2007 earthquake that has put five of the seven reactors at Kashiwazaki Kariwa out of action to this day. Hamaoka 4 is already back in operation, while units 1 and 2 were already permanently shut down at the time of the earthquake. Hamaoka 5 was more affected by the tremors and work to restart it is ongoing.