TOKYO — Japanese government regulators said Wednesday that for the first time they will conduct their own investigation into the country's nuclear crisis to address key unanswered questions.
The March 2011 earthquake and tsunami cut power and destroyed vital cooling systems at the Fukushima Dai-chi nuclear plant, causing meltdowns at three of its reactors. Several groups have already published the findings of their own investigations into the crisis, largely blaming the world's worst nuclear disaster since Chernobyl on botched crisis management, government-industry collusion and the tsunami.
But questions remain, and experts still suspect that the quake, not the tsunami, may have triggered the meltdowns. The Nuclear Regulation Authority said this issue, which could affect anti-quake measures at nuclear facilities nationwide, will be part of its investigation.
The authority said the investigation will also look into other issues, including how much and from where radiation leaked at the plant. The probe, to be conducted by a panel that will include outside experts, will start by the end of April and could take decades to complete because parts of the plant are still in horrible condition as the complex undergoes a 40-year cleanup process.
"Nobody has inspected the site very closely and we still have to sort out a lot of technical questions that remain unresolved," said Tetsuo Omura, a regulator in charge of reactor safety. "We have conflicting views, particularly about how the earthquake had impacted key safeguard equipment, a key question that needs to be addressed."
The plant suffered an extensive power failure last week after a rat short-circuited an outdoor switchboard, cutting fresh cooling water from four of its seven fuel storage pools for more than a day, a reminder that the fragile complex is running on makeshift equipment and is full of blind spots.