Plant planned tsunami risk review
The owner of Japan's Fukushima nuclear plant was planning a reassessment of tsunami risks just before last year's disaster, a briefing paper indicates.
Tokyo Electric Power presented the paper to Japan's nuclear regulators on March 7 2011, four days before the tsunami. It promised a new risk assessment by last October.
The paper summarised recent studies that suggested a tsunami as high as 33ft might hit the plant. That was higher than the 20ft surge it had been designed to withstand.
Reporters obtained the three-page document through a public records request to Japan's Nuclear and Industrial Safety Agency.