An employee with a subsidiary of Tokyo Electric Power Company Holdings Inc. testified in court Wednesday that the unit reported a need to install tide barriers to prevent flooding from a tsunami well before the March 2011 nuclear accident at Tepco’s Fukushima No. 1 nuclear plant.
According to the worker, the Tepco unit produced an estimate in March 2008 on the basis of long-term assessments released by a government organization, saying that a tsunami could occur with a height of 15.7 meters, which is above ground level at the nuclear plant site.
The estimate was presented at a meeting in June the same year that was attended by Sakae Muto, a former Tepco vice president.
The worker testified during a hearing at the Tokyo District Court that the Tepco unit estimated the tsunami height to reflect the latest information on a possible massive earthquake off Fukushima Prefecture, home to the now-devastated nuclear plant.
After finding that the nuclear plant site was vulnerable to flooding, the subsidiary reported at the meeting that installing 10-meter tide barriers would provide protection from a tsunami, the worker said.
The worker gave the testimony as a witness in the trial of three former Tepco executives, including Muto, 67, who were indicted in February 2016 for allegedly neglecting to take measures against massive tsunami. A prosecution inquest panel comprising ordinary citizens has overruled decisions by public prosecutors twice not to charge the executives. In the indictment, they were charged with professional negligence resulting in death and injury over the accident.
Lawyers appointed by the district court to act as prosecutors have said that former Tepco Chairman Tsunehisa Katsumata, 77, and former Vice President Ichiro Takekuro, 67, were also informed of the tsunami estimates on separate occasions. The lawyers claimed that the three former Tepco executives could have foreseen that a massive tsunami might hit the nuclear power plant.
The former executives denied the claim during the first hearing in their trial in June 2017, saying that the company would have been unable to prevent the accident even if measures were taken based on the estimate.