Yoshida’s call on seawater kept reactor cool as Tokyo dithered

by and


This is the sixth in a series on the Fukushima nuclear catastrophe based on the accounts of people who struggled to contain the crisis in its early stages. Job titles and ages are as of March 2011.

When the No. 1 reactor building exploded at the Fukushima No. 1 nuclear complex on March 12, 2011, blowing its concrete roof high into the sky, the employees were traumatized.

Still, the officials at Tokyo Electric Power Co. knew they had to continue injecting water into its reactor, which had lost all cooling ability after the massive earthquake and tsunami the day before robbed the power plant of all electricity and several backup generators.

At the time, Tepco was running out of fresh water to cool the reactor and had decided to use seawater that had pooled inside a large pit near the No. 3 reactor after the tsunami. Then planned to pump the water all the way over to the No. 1 reactor using three firetrucks.

They needed the help, however, of the Ground Self-Defense Force troops who had arrived at the plant in their own firetrucks. GSDF officer Yuichi Sato, 22, headed over to the pit for a second time later in the evening.

About 90 minutes before, he had been driving toward the pit when the hydrogen blast, set off by gas generated by the reactor’s melting nuclear fuel rods, gutted the No. 1 reactor building, hurling tons of debris into the air.

A chunk of steel frame from the building smashed into the passenger-side window of the truck, breaking the arm of Hiroyuki Ogawa, the 50-year-old chief of Tepco’s firefighting unit, who was guiding them to the site.

Sato, a member of a GSDF artillery regiment based in the prefecture, said he was afraid that another explosion might take place but knew he had to do his job.

The GSDF firetruck was supposed to pump seawater out of the pit and pass it to another GSDF firetruck, with Tepco’s firetruck later injecting it into the overheating reactor.

But heated exchanges broke out between officials from Tepco and one of its affiliates over who would run Tepco’s firetruck.

“Are you telling us to go? Can you guarantee our lives will be protected?” an official of affiliate Nanmei Kousan Co. shouted at Tomoyuki Arai, who had taken over as Tepco’s firefighting chief after Ogawa was injured. Arai was asking the affiliate to provide more manpower because the job of operating the firetrucks belongs to Nanmei and Tepco employees aren’t trained to run them.

Arai said he could not guarantee their safety, but added, “If we don’t go, things will get worse.”

A team including Arai and a Nanmei employee eventually left for the No. 1 reactor’s turbine building. As they approached it, their dosimeters climbed, warning of hazardous amounts of radiation in the area.

After Arai’s team replaced the hoses damaged by the hydrogen explosion, the three firetrucks were connected by 300 meters of hoses.

It was 7:04 p.m. when they started pumping the seawater into the reactor. But unknown to Sato and Arai, there was another struggle developing between the plant’s emergency response office and members of the prime minister’s office in Tokyo.

Given the critical need to inject seawater into the overheating No. 1 reactor, plant chief Masao Yoshida, 56, was in for a surprise when he was ordered over the phone to suspend the operation.

“Stop it immediately,” Ichiro Takekuro, a senior Tepco official who had been dispatched to the prime minister’s office to provide explanations on technical issues, said around 7:20 p.m.

“Why?” asked a defiant Yoshida. The plant was finally in a position to continuously inject water into the reactor and yet Takekuro, who had once been the head of Tepco’s nuclear division and knew better than anyone that the reactors needed to be cooled as soon as possible, was telling him to stop.

“Shut up! The prime minister’s office keeps on pestering me,” Takekuro, 64, said, before hanging up the phone without listening to what Yoshida had to say.

About 20 minutes before the call, Takekuro had explained to Prime Minister Naoto Kan that it would take more than an hour and a half to switch from freshwater to seawater injection at the reactor.

Kan, 64, told Takekuro in the meantime to consider whether there was a possibility of “recriticality” taking place. Kan was referring to a phenomenon in which melted fuel rods resume a chain reaction if seawater is used.

“I wanted him to consider the possibility because I was told that there was time before the seawater injection,” Kan later said.

Takekuro was aware that mixing boric acid with seawater could prevent recriticality, but before telling the prime minister about it, he learned from Yoshida by phone that the seawater injection had already begun.

Thinking that he could not tell Kan that reactor cooling operations with seawater had already commenced, Takekuro ordered Yoshida to stop the operation.

Yoshida was fuming after the telephone conversation. He could not understand why a decision by someone who was not at the site was being given priority. Dissatisfied, he consulted Tepco’s head office in Tokyo through a real-time teleconference.

The head office said the utility had no choice but to follow the order. Yoshida was told he should cease injecting seawater and describe the injections that had already taken place as having been done “on a trial basis.”

Yoshida could not understand what was wrong with seawater injection and turned to Shiro Hikita, 56, his most trusted subordinate, who knew all about the structure and design of the reactors, for a second opinion.

Emboldened by Hikita’s assurance that there was no problem, Yoshida then approached the Tepco employee who was supervising the seawater injection operation and whispered, “I will put on an act. No matter what happens, you must not stop injecting the water.”

Later, at 7:25 p.m., Yoshida said during a teleconference that the “trial” seawater injection would be temporarily halted on the prime minister’s order, but was expected to resume soon because Takekuro was negotiating the issue in Tokyo.

Hundreds of people at the plant’s emergency response office and senior Tepco officials in Tokyo believed the injection had been halted.

At 8:10 p.m., Yoshida declared that the seawater injection would “resume” following approval by the prime minister’s office. But the operation had never actually been suspended.

“I felt that, in the end, it had to be my decision. There was just no time for debate,” Yoshida later told a subordinate.

About two months after the nuclear crisis unfolded, media reports quoted government sources as saying Kan ordered the suspension of seawater injection. Opposition lawmakers then criticized Kan for intervening in Tepco’s efforts to contain the crisis.

Kan, however, denied giving such an order.

“I knew that water had to be injected, be it seawater or any kind of water. I was not informed that seawater injection had begun in the first place, so I could not have ordered its halt,” he said.