The governor had doubts, the attorney general went to court, neighbors were divided, and the head of the agency regulating nuclear power voted against it. But the Nuclear Regulatory Commission decided that a six-year review process was long enough and renewed the Pilgrim nuclear power plant’s operating license for 20 years. The May vote came a year after a nuclear disaster in Japan cast a shadow over the plant, since Pilgrim is the same model as the reactors that failed in Fukushima. Local watchdog group Pilgrim Watch had other issues beyond post-Sept. 11 and post-Fukushima safety worries: earthquakes, operator errors, radioactive water leaks, poisonous gases blown by shoreline winds, threats to sea life from warm water, and how to cope with the effects (and costs) of a potential meltdown. A few of these were still churning through the slow grind of the license review when the renewal was granted — infuriating opponents — but other factors mattered more to the commission’s majority. The NRC staff backed renewal. Management’s safety record was generally strong. Pilgrim was equipped with backup power sources to prevent the breakdown in cooling that doomed Fukushima. The decision means Pilgrim will go on lighting lights and casting shadows. It generates 10 percent of the state’s power; millions live nearby.