The Yoshida Testimony

Who is responsible for stopping a nuclear reactor that is spiraling out of control? Is that individual justified in taking flight when the reactor is finally about to burst?

Can local residents be evacuated properly under the direction of a prefectural governor, who has no way of finding out about the status of a nuclear reactor?

In the first place, are humans ever able to halt a nuclear reactor that has begun running amok?

Masao Yoshida, who served as general manager of the Fukushima No. 1 nuclear power plant during the triple meltdowns of March 2011, told about his actions and judgments for bringing the situation under control, sometimes with remorse, during the interviews with the government investigation panel.

Yoshida’s testimony is a convincing reminder of what a huge mistake it is to seek restarts of Japan’s nuclear reactors without trying to learn the truth of the disaster and making important decisions.

At around 6:15 a.m. on March 15, 2011, four days after the Great East Japan Earthquake and tsunami, a round table presided by Yoshida in an emergency response room on the second floor of the Fukushima No. 1 nuclear plant’s quake-proof control center building heard two important reports, almost simultaneously, from front-line workers.

One said that pressure in the suppression chamber, or the lower part of the containment vessel for the No. 2 reactor, had vanished. The other said an explosive sound had been heard.

Desperate efforts were going on at “1F”--insider slang for the Fukushima No. 1 nuclear plant--to keep its No. 2 reactor from going out of control. Conditions in the No. 2 reactor began to change sharply for the worse around noon on March 14.

There was, among others, a pressing need to curb a rise in pressure in the reactor containment vessel. Workers were eager to find a way to “vent,” or release gas from the interior of, the containment vessel to prevent it from bursting. They also wished to lower pressure in the pressure vessel and then use a fire engine to pump water into the reactor to cool nuclear fuel.

There was a report, slightly past 1 a.m. on March 15, that venting had succeeded and water had likely been pumped into the reactor. But another on-site report arrived only about two hours later, at 3:12 a.m., to deny that story.

“I guess no water has been pumped into the reactor,” said a shift supervisor who was overseeing operators at the “central operation,” or the central control room for the No. 1 and No. 2 reactors.

If a reactor receives no water, nuclear fuel inside could melt down from the intense heat it generates. If the situation is further left unattended, the fuel could penetrate the steel walls of the reactor pressure vessel, and then the thick steel walls of the containment vessel, and leak out into the living environment of humans.

——‘CONSERVATIVELY THINKING, THE CONTAINMENT VESSEL COULD HAVE BEEN DAMAGED’

The two important reports of the zero pressure and the explosive sound came at a time when such concerns were being raised. It was all too natural that those stories were taken to indicate that the No. 2 reactor’s containment vessel had possibly been destroyed.

A ruptured containment vessel would inevitably expose the 720 staff workers at the Fukushima No. 1 plant, at point-blank range, to large radiation doses. Thence came the talk of going to “2F”--the insider slang for the Fukushima No. 2 nuclear power plant.

At 6:21 a.m., operators in the central control rooms for the respective reactors at the plant were ordered to evacuate to the quake-proof control center building to minimize their radiation exposures.

At 6:22 a.m., all workers at the plant were ordered to wear charcoal masks containing active carbon to block oral and nasal inhalation of airborne radioactive substances.

At 6:27 a.m., the public address system began explaining procedures for taking shelter.

On-site data that arrived around that time denied that the No. 2 reactor’s containment vessel had been destroyed. It said radiation levels in the emergency response room in the quake-proof control center building, where Yoshida worked, remained relatively low at 15-20 microsieverts per hour.

Photo: Officials of TEPCO’s Fukushima Office explain to reporters about an explosive sound heard at the Fukushima No. 1 nuclear power plant. The photo was taken in the Fukushima Prefecture Jichi Kaikan building in the prefectural capital of Fukushima at 8:09 a.m. on March 15, 2011. (Koichi Murakami)

At 6:30 a.m., Yoshida spoke into a microphone of the teleconferencing system, “We will confirm parameters after having workers take temporary shelter,” where “parameters” referred to measurement instrument readings.

Two minutes later, TEPCO President Masataka Shimizu ordered everybody except for minimum staff to take shelter. Only an hour earlier, Shimizu had been dressed down by Kan, who visited TEPCO’s head office in person and said, “TEPCO would no longer exist if you were to withdraw (from the disaster site).”

At 6:33 a.m., Yoshida, at Shimizu’s behest, told team leaders who were in the emergency response room to present the names of their team members who should stay.

At 6:34 a.m., an announcement said radiation levels in the emergency response room remained unchanged.

The residual pressure in the dry well, the upper portion of the containment vessel, is clearly at odds with the story that the containment vessel had been ruptured. And in the first place, radiation levels in the emergency response room had not risen at all.

Yoshida issued an ordergave instructions at 6:42 a.m.

“Take shelter in areas of low radiation levels on the plant premises,” the orderhe said. “I will have you return if the headquarters later confirms that nothing is abnormal.”

The containment vessel was likely not destroyed, but on-site radiation levels should be measured, just in case. Everybody except for minimum staff who will stay should be put on standby, until safety is confirmed, in areas of low radiation levels on the grounds of the Fukushima No. 1 plant. The workers should return and resume their duties as soon as safety has been confirmed--so went Yoshida’s judgment and order.

Photo: Officials are busy at the Fukushima prefectural government’s disaster response headquarters in the prefectural capital of Fukushima at 8:35 a.m. on March 15, 2011, following reports of an explosive sound at the Fukushima No. 1 nuclear power plant. (Yoshinori Mizuno)

The radiation levels were measured. They stood at 5 millisieverts per hour as of 7:14 a.m. near the quake-proof control center building, almost unchanged from slightly past 2 p.m. on March 13, when the No. 3 reactor building had not yet exploded. That indicates Yoshida’s instructions to gave the right instruction when he ordered workers to take shelter nearbywere the right ones.

Around the same time, however, 650 workers, who had gotten into buses in front of the quake-proof control center building, were heading, against Yoshida’s orderapart from Yoshida’s instructions, for the Fukushima No. 2 nuclear plant, 10 km to the south, instead of areas of low radiation levels near the Fukushima No. 1 plant. Those workers included some of the GM-level staff, or senior employees on the level of division managers and section chiefs.

Yoshida was shocked to learn that some, though not all, of his GM-level staff had left for the Fukushima No. 2 nuclear plant.

TEPCO has so far given explanations that could be taken to imply that the massive staff defection totaking of shelter at the Fukushima No. 2 nuclear plant took place as planned. The utility has said it presumed that necessary staff should be left on the site to continue dealing with the crisis.

Foreign media outlets praised the dozens who remained on the site, whom they called the “Fukushima 50,” or the 50 heroes who stayed at the Fukushima No. 1 nuclear plant until the last moment.

But it is merely the consequences of staff defectionsgoing to the Fukushima No. 2 nuclear plant against Yoshida’s orderapart from Yoshida’s instructions that 69 workers, including the plant general manager himself, ended up staying at the Fukushima No. 1 nuclear plant.

A string of difficult developments erupted at the Fukushima No. 1 nuclear plant, where the general manager had no control over his staff workers, 90 percent of whom, including senior employees, had evacuated.

It was learned, first of all, that the site of the explosion was not the No. 2 reactor building, but the No. 4 reactor building, which nobody was on the alert for.

The explosion of the No. 4 reactor building, where regular inspections were under way and nuclear fuel was held in a storage pool, not in the reactor body, alarmed world experts of nuclear reactor structures.

The nuclear fuel storage pool, which is not shielded by a steel container such as a pressure vessel or a containment vessel, could spew radioactive substances directly into the humans’ living environment if the nuclear fuel were to ever melt from its own heat. And the storage pool contained enormous amounts of nuclear fuel.

It was later learned that the nuclear fuel in the No. 4 reactor building’s storage pool had never melted, and the explosion was blamed on a suspected hydrogen inflow from the No. 3 reactor. But a fire was spotted at 9:39 a.m., whereupon alarmed workers tried to use a fire engine, provided by the U.S. military, to extinguish it.

——‘I PLANNED TO RETAIN MINIMUM STAFF FOR WATER INJECTION AND OTHER OPERATIONS. I PLANNED TO STAY MYSELF, TOO.’

The No. 2 reactor did not remain under control. At 8:25 a.m., workers spotted white smoke rising from the No. 2 reactor building. They saw steam at 8:45 a.m.

It was confirmed at 9:45 a.m. that vast volumes of white steam were gushing out of an open blow-out panel attached to a wall of the reactor building. A voluminous mist was spotted in the reactor building at 10:51 a.m., with reported radiation levels of 150-300 millisieverts per hour in the reactor building.

White mists, steam and white smoke had also been spotted some time before the No. 1 and No. 3 reactor buildings exploded. TEPCO was, therefore, on the highest alert for those events, which it took for signs of gas leakage from a nuclear reactor containment vessel.

Radiation level readings near the main gate on the west side of the Fukushima No. 1 nuclear plant rose from 73.2-583.7 microsieverts per hour between 6 a.m. and 7 a.m., around the time the explosive sound was heard, to 234.7-1,390 microsieverts per hour between 7 a.m. and 8 a.m., around the time 90 percent of the staff evacuated to the Fukushima No. 2 nuclear plant. The readings rose to 8,217 microsieverts per hour at 8:31 a.m., when workers were panicking over the finding that the No. 4 reactor building was the site of the explosion, and to 11,930 microsieverts per hour, more than at any other time during the crisis, at 9 a.m. sharp.

Fukushima nuclear crisis: major events, radiation levels per hour near main gate to Fukushima No. 1 nuclear plant

Yoshida appeared to accept to a certain extent that his subordinates believed going to the Fukushima No. 2 nuclear plant was the right thing to do. But a comparison of time variations in the radiation levels and the emergence of the white smoke and steam from the No. 2 reactor building indicates that the Fukushima No. 1 nuclear plant was facing a really critical phase when hardly any work could be done properly because so many staff workers had withdrawn totaken shelter at the Fukushima No. 2 nuclear plant against their plant general manager’s order.

It is embarrassing that tThe government investigation panel, namely the government, which interviewed Yoshida over more than 28 hours, knew but never mentioneddid not mention in its report that evacuationsby many staff workers were taking place against an order during those critical moments.

TEPCO officials said the staff workers, who had withdrawn to the Fukushima No. 2 nuclear plant, returned only around noon.

While it is true that 69 workers, including Yoshida, never took flight, it remains to be seen if those 69 workers were enough to cope properly with the multiple disaster that was befalling four reactors simultaneously. That question remains open because the government investigation panel and TEPCO have disclosed very little information.

And on March 15, 2011, the day when all this was taking place, the Fukushima No. 1 nuclear plant spewed radioactive substances to the northwest, in the direction of Namie and Iitate, both in Fukushima Prefecture, at levels that were higher than at any other time and in land areas during the nuclear crisis and forced many residents there to evacuate their communities.

To be followed by Chapter 1, Section 2: “The hardest part to remember”