TOKYO -- Nuclear power returned to Japan's energy mix Thursday as the first reactor to be restarted since last year's earthquake and tsunami came back online, ending a nationwide shutdown that left the country without nuclear-generated electricity for the first time since 1970.
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The reactor at a plant in Ohi, in western Japan, began generating power just ahead of the release of the final report by a parliamentary investigative commission examining the crisis that the tsunami touched off in Fukushima, which suffered meltdowns, explosions and massive radiation leaks.
After the tsunami, all of Japan's working reactors were gradually taken offline for maintenance or safety checks. The country had been without nuclear power for two months.
Officials say the situation at the Fukushima plant has stabilized, though it will take decades to safely decommission and the area around it remains off limits because it is a health hazard.
Despite rising public opposition to restarts because of the Fukushima crisis, government officials and the utility that runs the Ohi plant say the reactor has passed stringent safety checks. They argue its output is needed to ward off blackouts as Japan enters its high-demand summer months.
"We have finally taken this first step," said Hideki Toyomatsu, vice president of Kansai Electric Power Co., which operates the plant. "But it is just a first step."
The company is hoping to restart another reactor in Ohi soon. That could pave the way for other plants around the country. In the meantime, officials have called on the nation to conserve energy.
The resumption of operations in Ohi has been hotly contested in Japan, and coming ahead of the parliamentary commission's final report has raised questions over how seriously the government is trying to learn from the Fukushima crisis.
Large demonstrations against the restart have been held each week outside of the prime minister's office, reflecting deep grassroots opposition. Before the crisis, Japan got one-third of its electricity from nuclear plants.
Experts and activists have criticized Prime Minister Yoshihiko Noda's government, saying it is putting business ahead of safety by going forward with the resumption before studying the findings and recommendations in the report.
The 10-member panel, appointed by parliament in December, has interviewed hundreds of plant workers, company and government officials, including then-Prime Minister Naoto Kan.
Committee chairman Kiyoshi Kurokawa said the report contains "proposals for the future" and urged the parliament to put them into action. The report was to be submitted later Thursday, and he did not give further details.
Other groups, including a private probe panel, have detailed a serious lack of communication between the government and the Fukushima plant's operator, Tokyo Electric Power Co. - or TEPCO - and a failure by both to provide the public with important information on radiation leaks.
Thursday's report was likely to echo that claim.
An interim report by the parliamentary commission blamed Kan for trying to micromanage Fukushima's response, which it said made matters worse. It also highlighted a flawed chain of command and lax preparations as factors that worsened the crisis.
The panel has called for a binding guideline for nuclear operators to upgrade safety and crisis plans without taking into consideration their cost efficiency. It is also looking into the role the earthquake itself played in the reactor damage, a key question that has remained unanswered or largely denied in previous reports.
TEPCO, which has already released the results of its own internal investigation, said it found no evidence of major damage from the earthquake. It claims the unanticipated size of the tsunami was the primary cause, but acknowledges its tsunami plans were too optimistic and initial communications were problematic.