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The explosion that went off in the No. 3 reactor at the Fukushima No. 1 nuclear power plant on the morning of March 14, 2011, caused serious damage to the neighboring No. 2 reactor as well.
The electrical circuits were destroyed, making it impossible to let steam out of the reactor. Pressure inside the reactor core rose, while the water level fell. If the water level kept sinking, fuel rods would become exposed, possibly causing a core meltdown.
At 4 p.m. on March 14, Maj. Gen. Yuki Imaura, 54, vice commander of the Ground Self-Defense Force’s Central Readiness Force (CRF), arrived at the disaster-stricken plant’s off-site center, a facility used as an operational base for dealing with emergencies.
The off-site center, located five kilometers southwest of the plant, was used to house the government’s nuclear emergency response headquarters. It served as the local headquarters for the battle against the galloping nuclear crisis.
Around the time Imaura arrived at the facility, the No. 2 reactor was in an increasingly dangerous situation. Exactly at 4 p.m., the prime minister’s office became aware of the possibility that fuel rods in the reactor could become exposed.
As it turned out, Imaura stayed at the off-site center for only 18 hours until the government’s crisis response headquarters were moved to the Fukushima prefectural government’s building the following morning. The GSDF major general would never forget the stormy night he spent at the off-site center amid the chaos of responding to the nuclear disaster.
According to records left by Imaura, at 6:45 p.m., he went to the office of Motohisa Ikeda, senior vice minister of the Ministry of Economy, Trade and Industry, who supervised the headquarters. The office was a private room on the second floor of the building.
Ikeda convened an emergency meeting of top officials in the room. Besides Ikeda and Imaura, the meeting was also attended by Masao Uchibori, vice governor of Fukushima Prefecture; Shinichi Kuroki, deputy director-general for nuclear power at the Nuclear and Industrial Safety Agency; and Akio Komori, a managing director at Tokyo Electric Power Co., the operator of the crippled nuclear plant.
“The No. 2 reactor is in a dangerous situation,” Komori said to Ikeda. “We are worried that the nuclear core may have started melting down” at the reactor. “The worst possible case could occur four hours from now,” he warned.
Komori’s dire warning prompted the attendees to consider moving the headquarters to a safe location. They chose the Fukushima prefectural government’s building, 60 kilometers from the plant, as the evacuation site.
But they didn’t determine when to start the evacuation and decided instead to dispatch an advance unit led by Uchibori to start preparations for the relocation.
The people who were at the meeting also heard the report that some 350 local residents appeared to be still within 20 kilometers from the Fukushima plant. But they didn’t discuss the evacuation of the residents.
At 8 p.m., a general meeting of all those working at the off-site center was held in a large room. Ikeda informed the staff of the decision about evacuating. Immediately after the meeting, Uchibori headed off to the prefectural government building.
At 12:30 a.m. on March 15, a radiation warning was announced over the facility’s public address system.
“Radiation levels are rising. Put on a protective suit and a protective mask immediately,” the announcement said.
When SDF personnel asked TEPCO employees about radiation levels, they were told that the readings were 700 microsieverts per hour within the building and 1 millisievert outside.
At 2 a.m., the headquarters staff was instructed to take potassium iodine pills that could protect their thyroid glands if taken before or shortly after exposure to radiation.
After the advance unit left the off-site center, it was found that many people other than the members of the unit had also gone.
In a general meeting held before dawn on March 15, Ikeda raised his voice and said some people other than those who had been assigned to the unit had lost their nerve and left the facility.
“We have not decided to abandon this place yet,” he said. “Hold your ground and do your jobs,” he yelled.
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