More than eight months after disaster struck at its Fukushima Daiichi nuclear plant, Tokyo Electric Power Co. said an internal investigation, its first public assessment of its handling of the crisis, found no evidence of significant errors in its response.
But the plant operator also conceded it still didn't have answers to some key questions about the disaster, in the latest reminder of how little is still known about how the March 11 accident unfolded and what the current status of the plant is.
The findings were part of an interim report on the accident that Tepco released Friday.
The report supports Tepco's line that its plant complied with earthquake safety standards. But Tepco acknowledged it hasn't yet resolved a fundamental problem: pinpointing the source of continued leaks of irradiated water from the plant. It also said it doesn't know why radiation releases spiked four days into the crisis.
Complicating the picture, the utility retracted an earlier statement that an explosion took place in Unit 2 of the plant on March 15, the day of the radiation increase, removing one possible cause for the higher radiation levels. Tepco initially said there were two explosions on March 15, one believed to be inside the suppression chamber of Unit 2 and another near the rooftop of Unit 4. This followed explosions at Unit 1 on March 12 and at Unit 3 at March 14.
