Читать книгу Meltdown - Yoichi Funabashi - Страница 32

Pumping water into the nuclear reactors is only a feasible strategy if there is an abundant water supply. However, their source of fresh water started to run dry before their eyes. Since they had no alternative source of water, there was nothing to do but pump in seawater.

Around noon on March 12, Yoshida decided on injecting seawater into Unit 1, and instructed the station ERC and the in-house firefighting team to look into a seawater injection line.

Just before three p.m., the water in the fire protection tank dried up completely.⁵

After three p.m., TEPCO reported to NISA their plan to “inject seawater.”

Although they spoke of seawater injection, they did not mean direct intake from the sea. The water source they would use was from the tsunami, which had flowed into the backwash valve pit that acts as the fire protection water tank in the powerplant.

They may have had a plan, but they were slow to implement it. METI Minister Kaieda started hinting at “orders” again.

“This company doesn’t do anything unless it’s ordered to, just like with the vent.”

Kaieda told his secretary, “Both the government and TEPCO have to be responsible for injecting seawater. If they drag their heels, I’ll order them to do it.”⁶

3:20 P.M. TEPCO sent a fax to NISA, reporting their plan to “inject seawater,” and started preparing at 3:30 p.m. It was immediately after this that the explosion in Unit 1 took place. The walls on the fifth floor of the reactor building were completely blown away, baring the steel frame.

Three TEPCO employees and two Nanmei Kosan employees working at the site were injured. The TEPCO employees in charge of the relief operation had to hurry to help and transport the injured. Those remaining fled to the Anti-Seismic Building.⁷

There was radioactive debris scattered all over, including the building’s steel cladding, and onsite radiation was mounting. The operational environment took an immediate turn for the worse.

4:27 P.M. Yoshida reported to the government an article 15.1 event (an abnormal increase in radiation near the station perimeters) under the Act on Special Measures Concerning Nuclear Emergency Preparedness.

The firefighting hoses on the fire engines they had readied for injecting seawater into Unit 1 were damaged. After cleaning away the debris, they were forced to lay a new hose over hundreds of meters from the backwash valve pit in front of Unit 3 (RB) to the filling port of Unit 1 (RB). Once again, it was the Nanmei Kosan employees who were drafted for the job.

At 5:55 p.m., Kaieda issued the command to inject seawater in accordance with paragraph 3, article 64 of the Act on the Regulation of Nuclear Source Material, Nuclear Fuel Material, and Reactors. After turning to Takekuro and telling him, “The act requires the minister to convey the command to the company president, but I order him via you,” Kaieda instructed Hiraoka to “draft up the necessary papers.” (NISA released the papers after eight p.m.)⁸

AROUND SIX P.M. The prime minister’s office at the Kantei.

Kan was holding a meeting on injecting seawater. Kaieda, Hosono, Madarame, and Takekuro were in attendance.

Kaieda was thinking of reporting that he had just issued the command to inject seawater according to the act, but Kan started talking before he could do so. He made two points.

One was, “There’s been a hydrogen explosion. You have to ascertain whether the pipes are still working or not.”

The other was, “Is there no possibility of recriticality? If there is, what countermeasures need to be taken?”

Criticality is the state where uranium or plutonium triggers a chain reaction. If these materials over and above a certain amount are placed in a single location, there is an extreme danger that they will suddenly trigger a chain reaction of nuclear fission and start emitting radiation and heat.

Japan had experienced criticality with the JOC Tokaimura accident in 1999. At the time, this was ranked as level 4 (accident with local consequences) on the international nuclear events scale. The JOC accident was still fresh in people’s minds. It wasn’t just Kan who was worried about criticality. Reports of “no neutrons” were being filed almost daily from the field to TEPCO Head Office via videoconference.

Takekuro’s response to the question about the pipes was, “They have confirmed that the pump is still working. But they haven’t confirmed the pipes yet.”

Regarding the danger of criticality, Hiraoka replied, “The danger of criticality will not increase.”

Takekuro was of the same opinion, commenting, “Reaching criticality is a difficult trick, artistically. Criticality takes place in the most delicate circumstances, and there is no way that could happen if you pump in seawater with all its impurities.”

Kan glanced in Madarame’s direction. Madarame was less emphatic.

“If you say so, then NISA …”

“Use your own judgment! There’s no way it can happen, right?”

“No, it may happen.”

“Which is it?!”

“I don’t think it likely, but I can’t say impossible.”

Madarame’s voice was almost a whisper.

Hosono was taken aback by the words “can’t say impossible.”

So, there’s a possibility of recriticality.

Kan was frustrated by Madarame’s vagueness.

“Wasn’t it you who said there wouldn’t be a hydrogen explosion?”

Some of the people in the room got the feeling that “Kan’s not going to listen to Madarame anymore.” Even so, Madarame pleaded, close to tears, “In any event, we have to get water in there now.”

“Let’s flood the reactor with seawater.”

Madarame insisted on injecting seawater.⁹

The question was, however, that even if pumping in seawater was inevitable, were people on the ground at Fukushima Daiichi able to make the necessary preparations?

Takekuro stated that it was likely the firefighting hoses had been damaged by the hydrogen blast and that it would probably take one to two hours to replace them.

The reason why Kan was so fixated on the question of recriticality was because it related to the other item on the agenda—namely, expanding the evacuation zone. If recriticality was to take place, there was the problem that a ten-kilometer evacuation radius would no longer be sufficient, and they would have to order the evacuation of local residents from a twenty-kilometer radius. No objections were raised.

Kan also asked, “Won’t the salt have an adverse impact if you pump in seawater?” adding, “Check out the technical aspects thoroughly.” The meeting closed, to reconvene in two hours to make a decision.

During the meeting, Takekuro had borrowed the prime minister’s secretary’s landline in the waiting room to phone TEPCO Head Office.

“Muto, please decide on the company’s course of action.”

“Please hurry with an organizational decision.”

Apparently, it was TEPCO Vice President Sakae Muto on the other end of the line. Takekuro badgered him over and over again. There was a growing distrust of TEPCO. Even staff members at the Nuclear Safety Commission were entertaining doubts about TEPCO’s seemingly endless inability to decide whether they were going to inject seawater or not.

“Is TEPCO hesitating about pumping in seawater? If that’s the case, it’s probably because they’re worried they won’t be able to use the reactor again.”

“A single reactor costs between 300 and 400 billion yen. Is that what’s holding them back?”

“Even if the Unit 1 explosion was unavoidable, are they trying to avoid having to pump seawater into Units 2 and 3?”¹⁰