A spokesman for the Tokyo District Public Prosecutor’s Office said the prosecutors decided not to issue charges due to insufficient evidence.
“We conclude that there is not enough evidence to suggest that TEPCO executives could have predicted or could have avoided (the accident),” said Ryoichi Nakahara, deputy chief prosecutor of the Tokyo District Public Prosecutor’s Office.
He said prosecutors had questioned a wider group of experts following the July panel ruling but reached the same conclusion.
The move is the latest in a tussle between legal authorities and an angry public over who should take responsibility for the reactor meltdowns in 2011 that forced tens of thousands from their homes, triggered by a massive 9.0-magnitude earthquake.
Public waiting for someone to be held accountable
A parliamentary report has said the Fukushima disaster was man-made, caused by Japan’s culture of “reflexive obedience”, but no one has been punished criminally.
There is a growing perception publicly that cosy ties between government, regulators and nuclear operators have insulated executives of plant operator TEPCO.
Prosecutors declined in 2013 to charge more than 30 TEPCO and government officials who had been accused by residents of ignoring the risks of natural disasters and failing to respond appropriately to the nuclear crisis.
The Tokyo District Prosecutors Office reopened the case after a citizens’ panel ruled in July that the three former TEPCO executives, including former chairman Tsunehisa Katsumata, should be indicted over their handling of the world’s worst nuclear disaster since Chernobyl in 1986.
The panel had ruled that Mr Katsumata, along with former executive vice-presidents Sakae Muto and Ichiro Takekuro, had failed to protect the Fukushima Daiichi nuclear plant despite warnings of the dangers it faced from big tsunamis.
The 11 unidentified citizens on the panel, the Prosecutorial Review Commission, can still force an indictment by court-appointed lawyers if eight members of the panel now vote in favour.
The commissions, made up of citizens selected by lottery, are a rarely used but high-profile feature of Japan’s legal system, introduced after World War Two to curb bureaucratic overreach.
Under Japanese law, if the judicial review panel challenges that decision a second time, a group of court-appointed lawyers would then be compelled to press charges.