The hard questions that needed to be asked never got any airing by the Diet panel looking into last year's nuclear accident.
The hard questions that needed to be asked never got any airing by the Diet panel looking into last year's nuclear accident.
A key point was this: What sort of crisis management structure did Tokyo Electric Power Co., operator of the stricken Fukushima No. 1 nuclear power plant, have in place?
The Fukushima Nuclear Accident Independent Investigation Commission effectively wound up its mission May 28 when Naoto Kan, who was prime minister at the time, gave his side of the story. The panel is due to issue its final report in June.
Not only did the panel uncover little about the crisis management setup at TEPCO, but major discrepancies in statements by government officials and TEPCO executives also went unexplained.
As for TEPCO's handling of the nuclear accident, two key procedures were not addressed: the operating of emergency cooling equipment to cool reactor cores and venting to reduce the pressure within the containment vessels of the reactor cores.
If the cooling equipment had functioned properly, along with venting to lower the pressure so water could be pumped into the reactor cores, meltdowns and damage to the containment vessels that led to the release of large amounts of radioactive materials might have been avoided.
But members of the Diet panel did not press TEPCO executives about those two crucial procedures.
The central government's Investigation Committee on the Accident at the Fukushima Nuclear Power Stations and TEPCO's Fukushima Nuclear Accidents Investigation Committee have released interim reports on the disaster.
The private-sector Independent Investigation Commission on the Fukushima Daiichi (No. 1) Nuclear Accident also released its final report in late February.
The government panel's interim report issued in December said the isolation condensers (IC) in the No. 1 reactor stopped functioning shortly after the plant was inundated by tsunami generated by the March 11 Great East Japan Earthquake.
However, the report said plant workers, senior officials at the facility and those at TEPCO headquarters were slow to realize that the ICs had stopped operating. That led to a delay in finding other methods to cool the core.
At the No. 3 reactor, a plant worker manually stopped the high pressure coolant injection (HPCI) system to avoid causing damage, but alternative pumping methods had no effect.
None of the four investigation panels has looked into the connection between the handling of those procedures by TEPCO and the meltdowns and hydrogen explosions that occurred in the days that followed.
TEPCO's chairman, Tsunehisa Katsumata, has ducked a question about the utility's handling of the ICs. "As we learn more about the various circumstances, there may be aspects that we can clarify," Katsumata said.
It also remains unclear why TEPCO delayed venting at the reactors.
Appearing before the Diet panel, Banri Kaieda, the industry minister at the time, said, "I felt that TEPCO was being hesitant as if to show that the accident was not as severe as it appeared."
Kan was also critical and said: "Although Kaieda had given his consent to begin venting, it did not happen for several hours. I got no clear answer when I asked why. That was a very troubling development."
The government investigation panel found no clear evidence that TEPCO hesitated on the matter of venting.
However, the private-sector investigation panel speculated that TEPCO delayed the procedure in hopes that it would force the central government to issue the order: That way, so the thinking goes, TEPCO could avoid responsibility for the massive discharge of radioactive materials.
The private panel called on both the government and Diet investigative panels to look into the issue to clear up any doubts.
The Diet panel also did not shed light on conflicting accounts of whether TEPCO executives asked the central government to allow them to evacuate the workers at the Fukushima No. 1 plant.
Kan said he learned of the request from Kaieda around 3 a.m. on March 15.
At the Diet panel, Kan said: "When I heard about the evacuation request, I was feeling that I had to stake my political life on resolving the situation. That made me feel the request was totally out of line."
Kan backed up the earlier statements by Kaieda and Yukio Edano, the chief Cabinet secretary at the time, who both said they considered the TEPCO request to mean pulling out all workers.
Kan also blasted TEPCO for blaming him for ordering that the pumping of seawater into the reactor cores be stopped.
TEPCO executives who have appeared before the Diet panel said Kan raised concerns about the possibility of reaching recriticality by switching to pumping in seawater rather than continuing to use fresh water.
However, Kan said on May 28 that Ichiro Takekuro, the senior TEPCO expert who was based at the prime minister's office at the time of the accident, gave the instructions to stop pumping seawater.
"I learned later that Takekuro decided on his own to tell Masao Yoshida (who was then head of the Fukushima plant) to stop pumping," Kan said.
He also criticized Takekuro and said: "A professional among professionals in nuclear energy should have known that there was no connection between switching from fresh water to seawater and reaching recriticality. I cannot understand how such an individual could have told Yoshida to stop pumping."
While Masataka Shimizu, then TEPCO's president, is said to have requested that all TEPCO workers be evacuated from the Fukushima No. 1 nuclear plant, he has not been called before the Diet panel.
The panel has also not exercised its authority to summon government officials and TEPCO executives as sworn witnesses.