TOKYO - The 2011 accident caused by Tokyo Electric Power Company at the Fukushima Daiichi nuclear plant is estimated to cost 23.4 trillion yen ($147 billion) for decontamination, compensation and cleanup of the damaged reactors.
Even now, 15 years later, about 24,000 people remain displaced and unable to return home, and many lives were irreversibly altered.
Had it not been for delays in work at the plant that left a large volume of water on site, far more radioactive materials could have been released, potentially forcing as many as 50 million people, including those in Tokyo, to evacuate.
We were confronted with a disaster of that magnitude. One would have expected power utilities to examine seismic risks far more carefully. Yet Chubu Electric Power Co. is said to have falsified earthquake-related data at its Hamaoka nuclear power plant in an attempt to circumvent regulatory screening. The power industry's failure to reflect is astonishing.
The criminal trial of former TEPCO executives has brought to light the way in which the utility delayed the implementation of tsunami countermeasures.
Initially, the company was scheduled to complete tsunami countermeasures two years before the accident. However, three years before the disaster, when it became clear that preparations were needed for a tsunami nearly three times higher than previously assumed, the company began delaying action under the pretext of having academic societies examine the issue.
Efforts were also made to lobby influential researchers to prevent information about the tsunami from being disclosed during open discussions. The heavy-handed approach was such that one of the utility's engineers lamented in an email, "We cannot readily come up with an explanation that would satisfy the public, such as (local governments and the media)."
Tohoku Electric Power Co. had sought to assume higher tsunami levels off the Fukushima coast, but because doing so would have exposed the inadequacy of TEPCO's countermeasures, TEPCO even had Tohoku Electric revise its assumptions.
The court proceedings ended in March 2025 with the dismissal of the final appeal, finalizing the acquittal of criminal liability. TEPCO, however, has acknowledged that it "failed to prevent an accident that should have been avoided through prior preparedness." Even so, there is no record of TEPCO going so far as to fabricate seismic data. In terms of misconduct, Chubu Electric surpasses TEPCO.
Chubu Electric submitted ground motion assumptions for screening to restart the Hamaoka No. 3 and No. 4 reactors that were about 40 percent lower than those for the No. 5 reactor, which is located only about 300 meters away. The company explained that the difference was due to variations in the underground structure. Depending on how an earthquake occurs, stronger shaking may have needed to be assumed for the No. 3 and No. 4 reactors. This raises the possibility that the data were falsified to expedite their restart.
In this case, there were conscientious individuals. For example, personnel from Chubu Electric or its affiliates filed an external report, and a TEPCO employee continued to press for tsunami countermeasures despite repeated rejections. While the full details of the misconduct at Chubu Electric remain unclear, it appears that organizational logic prioritizing schedules and management over safety has not changed and continues to override the efforts of such individuals.
Before the TEPCO disaster, the government side responsible for regulation also proved inadequate. Even after regulators summoned TEPCO officials and urged them to recalculate tsunami risks based on the latest research, TEPCO resisted for 40 minutes. Ultimately, the process was delayed by nine years and failed to be completed in time.
Four years before the accident, regulators strongly urged TEPCO to take countermeasures against tsunamis that exceeded previous assumptions, but were ultimately brushed off, later saying TEPCO "did not respond positively." These failures were kept hidden for nearly seven years after the accident.
Given Chubu Electric's lack of change, it seems that the Nuclear Regulation Authority is still being taken lightly by power utilities. The NRA must thoroughly investigate the Hamaoka issue, impose strict penalties and strengthen its screening of other nuclear plants. Otherwise, the country risks heading down the path toward another accident.
Takashi Soeda was born in 1964 in Matsue. After working as a reporter for the Asahi Shimbun, he became a freelance journalist. His works include "What Became Clear 10 Years After the TEPCO Nuclear Accident," among others.
