Three former Tokyo Electric Power Co. (TEPCO) executives on Friday pleaded not guilty to professional negligence related to the fatal meltdowns at the Fukushima Daiichi nuclear power plant in March 2011.
The three former executives, Tsunehisa Katsumata and former Vice Presidents Ichiro Takekuro and Sakae Muto took the stand at the Tokyo District Court, marking the first criminal trial over the disaster.
Tsunehisa Katsumata who was chairman of TEPCO when the Daichi plant was hit by a massive earthquake-triggered tsunami which knocked out the plant's key cooling systems leading to multiple core meltdowns, told the court, "It was impossible to predict the accident."
As well as offering apologies, the two former vice-presidents also pleaded not guilty as widely expected based on former defense counsels who have argued that there was no way to predict that such a colossal tsunami would cripple the power plant in the devastating way it did.
But while a number of investigations on the cause and potential blame for the worst commercial nuclear disaster in history have been launched and concluded by TEPCO and third party entities, the Fukushima residents plaintiffs' group believe that the three executives showed professional negligence.
Specially appointed lawyers at the hearing are basing their arguments around the idea that the officials could have anticipated that the plant might be hit and subsequently inundated by a huge tsunami, with this scenario being based on a simulation that a TEPCO subsidiary produced in March 2008.
According to data from the test, the nuclear facility could theoretically be hit by a tsunami of almost 16 meters in height, with TEPCO's subsidiary, according to the lawyers, proposing to the utility in May 2008 specific procedures necessary, such as building a sea wall, to be carried out to better prepare the plant's defenses against such an occurrence.
"We will argue that the three clearly failed to perform their duty of care by showing they downplayed the significance of the estimate, neglected information-gathering and sharing, and were not aware of the need to take measures," the lawyers said.
They added that at a subsequent meeting, the three executives had also been made aware of the dangers presented by a 14-meter high tsunami striking the plant and the need to build a sizable sea wall to protect the plant.
This vital piece of information came from Masao Yoshida who at the time was in charge of nuclear equipment issues.
The data on the impending danger of possible tsunamis striking the plant were conveyed to Takekuro and Muto at the time, the lawyers said, although Katsumata told prosecutors that he had "no memory of being briefed about the information."
"The three should have been able to predict that the plant would be hit by tsunami on a scale that would overwhelm the site," the lawyers said.
Prior to this, a criminal case in the past has not been successfully pursued based on the assumption that the nuclear disaster could not have been avoided, regardless of whether or not the three former executives had taken preemptive defensive measures based on the two sets of data that had urged them to do so.
Following moves to take TEPCO executives and government officials to court from 2012, public prosecutors in 2013 decided not to file criminal charges against a number of officials, but Katsumata, Takekuro and Muto were indicted in February 2016 by court-appointed lawyers, in line with the decision by a prosecution inquest panel of randomly selected citizens.
According to official accounts, they are accused of professional negligence resulting in the deaths of 44 people, including hospital patients who were forced to stay at evacuation shelters for long periods of time.
The six-reactor plant, located on ground 10 meters above sea level on the coast of the Pacific Ocean in Fukushima Prefecture, was battered by a 9.0-magnitude earthquake-triggered tsunami on March 11, 2011, which flooded key power supply facilities including essential backup cooling equipment.
The Number 1 to Number 3 reactors suffered fuel meltdowns as a result of the crippled cooling systems and three units were vastly damaged by hydrogen explosions.
The disaster caused at least 150,000 people in Fukushima to flee their homes to escape the increasingly high levels of radiation in the air, initially, but which also went on to affect the land and the sea.
Only recently have residents begun returning to their homes in the prefecture while TEPCO, which was bailed out by the government, grapples with the lengthy task of decommissioning the still unstable plant and carries out ongoing decontamination and radiation cleanup work which is likely to take decades.