Читать книгу Meltdown - Yoichi Funabashi - Страница 36

MARCH 13. Despite it being Sunday, Toshiba’s chief engineer, Osamu Maekawa, was in Toshiba’s Isogo Engineering Center (IEC) in Yokohama from the early hours of the morning. The IEC was the pride and base for research and development of world-leading nuclear reactor manufacturer: Toshiba. Toshiba had built Units 2, 3, 5, and 6 at Fukushima Daiichi NPS. Of those, Units 2 and 6 had been joint projects with America’s General Electric (GE). (GE had built Unit 1 on its own, and Unit 4 had been built by Hitachi.)

Maekawa had joined Toshiba in 1981. His entire career had been in reactors, and he was currently the most senior official in Toshiba’s engineering staff. He was working in his casual clothes when he received an urgent call from the Head Office in Shibaura, Tokyo. It was Norio Sasaki, the CEO.

“Can you come straight to the Head Office? I’ve been called to see the prime minister at eleven a.m. Won’t you come with me?”

Sasaki had joined the company in 1972. The following year, as a trainee, he had been involved in planning the layout, plumbing, and air ventilation for Unit 3 at Fukushima Daiichi NPS. He later served as design director for the pressure vessel.

“The prime minister says he wants to hear from engineers actually involved in running the reactor.”

They agreed to go with a team of six, including officials in charge of control, fuel, and reactor cores, so they would be able to answer any questions. Maekawa left the IEC and, upon arriving to the Head Office, changed into a business suit. He realized he was wearing sneakers. While he was not keen on visiting the Kantei in this kind of attire, it could not be helped.

ELEVEN A.M., MARCH 13. The prime minister’s office. The delegation greeted Prime Minister Naoto Kan, Chief Cabinet Secretary Yukio Edano, and Deputy Chief Cabinet Secretary Tetsuro Fukuyama. Edano was wearing sneakers. Maekawa felt a little more comfortable.

The discussion immediately turned to the situation at Unit 3. Sasaki said, “If things are left as they stand, both Units 2 and 3 will explode.” According to the reactor core simulation carried out by Toshiba’s IEC, the containment vessel of Unit 3 was full of hydrogen and in a dangerous state.

“We’re also exploring various ways of avoiding an explosion.”

“Can’t you open a hole in the roof or something, and let the hydrogen escape from there?”

“There’s a danger that a spark could start a fire. I think it would be better to cut through it using high-pressure water.”

“Is that so? If there’s any way of avoiding another explosion, please do it. The government will help you in any way it can. So, we’d like you to help us as well.”

What Sasaki had mentioned was an operation that was already covertly being readied at the Onahama Coal Center in Fukushima Prefecture. This was a coal storage depot located some fifty kilometers from Fukushima Daiichi NPS. Along with J-Village, the Japan national football team training location, it was acting as one of the emergency response support centers.

Toshiba had started sending batteries and pumps there on March 11, immediately after the quake. Behind the scenes, they were considering two options for Unit 3. The first was a so-called air-ventilation strategy, which involved restoring the normal air ventilation and extracting the hydrogen. The second was a roof-opening strategy, which involved opening a hole in the roof to let the hydrogen escape.

They had also considered flying in a helicopter from above, attaching a drilling rig to the roof, and running for their lives. The drilling rig was a container-like frame that would “stick to the roof like glue and punch out a hole.” However, opening a hole up on the roof with something saw-like would set off sparks and might be dangerous. So, they would try using water to open a hole in a so-called water-jetting technique. Toshiba had already set up a life-size mockup.

The discussion on the morning of that day between TEPCO Head Office and the Fukushima site about ways of “using something to open the roof” was, in fact, referring to this water jet of Toshiba’s.

However, there were problems. They were no longer able to have equipment delivered into the Fukushima Daiichi site. At 6:25 p.m. on March 12, the government had issued an order for local residents within a twenty-kilometer radius to evacuate. Since then, not a single piece of equipment had been delivered from Onahama Coal Center to Fukushima Daiichi. Sasaki met Kan a second time in his office around one p.m. the same day and raised this issue.

“They’re stuck at the barrier at the twenty-kilometer line and can’t move. Something needs to be done.”

“We’ll act immediately.”

Sasaki also mentioned that a Toshiba team had been turned back at the main gate to Fukushima Daiichi NPS. Toshiba had put together a twenty-five-man team for restoring Units 5 and 6 at Fukushima Daiichi. He was sure that they could have the reactors back up and running in two days if they worked day and night. But, denied entrance at the main gate, they had turned back.

Fukushima Daiichi wouldn’t let the Toshiba team in even after they showed their Toshiba IDs. No one was allowed in unless they had registered beforehand and received a badge. Most of the team had not registered beforehand. The Toshiba engineers were unconvinced.

Do the staff on the ground not want outsiders getting into the Anti-Seismic Building at a time of crisis? Is that why they won’t let us in?

Toshiba had built an Anti-Seismic Building at its Isogo Engineering Center after TEPCO had shut down its reactors at Kashiwazaki-Kariwa following the 2007 Chuetsu earthquake. It was the first of its kind in Japan. Following their lead, TEPCO had built them at Kashiwazaki-Kariwa, Fukushima Daiichi, and Fukushima Daini.

Sasaki asked Kan, “There’s no way we can help out when things are like this. Can you get some government people to speak to them?”

After leaving the prime minister’s office, Sasaki pointed at Maekawa and told Fukuyama, “Fukuyama-san, I’m leaving him behind. He’s our top engineer.”

Maekawa was surprised, because he hadn’t heard anything about that from Sasaki beforehand. Maekawa stayed at the Kantei until the morning of March 15, then moved over to TEPCO after Kan had ventured into the Head Office.³⁰

At 1:12 p.m. on March 13, TEPCO started pumping seawater into Unit 3. They had also added boric acid.

At 1:52 p.m., the monitoring car inside Fukushima Daiichi Station recorded 1,600 microsieverts/hour (1.6 millisieverts). It was on the western mountain side of the site. It was the highest reading since the start of the emergency.³¹

2:12 P.M. ON MARCH 13. Videoconference.

Head Office safety team: “Since it had been previously 40-50 microsieverts (0.04-0.05 millisieverts), we are now in a situation in which it is considerably higher.”

Yoshida: “Or, rather, it’s an article 15 again.”

If a radiation dose in excess of 500 microsieverts (0.5 millisieverts) had been observed at the site boundary, this fell under article 15 of the Nuclear Disaster Special Measures Act.

Head Office safety team: “The unit we’re now using is mSv (millisievert), and 30 or 50 mSv/h is a very high dose. The area around the Anti-Seismic Building, too, is 5-10 mSv. This means just a round trip from the Anti-Seismic Building to the office building and back involves exposure to a dosage of 1 mSv and the situation is that after the explosion in Unit 1, the radiation is higher.”³²

3:28 P.M., MARCH 13. Edano issued a warning at his press conference: “There is a possibility that a hydrogen explosion like the one in Unit 1 will occur in Unit 3.”

3:07 A.M., MARCH 14. The onsite safety team reported the latest dose at the Fukushima Daiichi NPS near the main gate.

“At 02:20, 751. At 02:30, 4,133.”

“Oh, my God!”

Yoshida couldn’t help but raise his voice at such a high dose. The radiation dose had jumped to 4,133 mSv/h (4.133 millisieverts).³³

In the videoconference at 5:50 a.m. on March 14, Yoshida made a formal statement. “Erm, so, I’ll explain the situation at the power plant a little, since I believe the situation is not the best.”

Although water injection was resumed at Unit 3 after an interruption, the drywell pressure had gradually increased. They had increased the amount of water being pumped in to nearly double, but the upward trend of the pressure had not abated. In addition, the water level had become volatile.

“We can’t help but think that there is a strong possibility that some kind of reaction is taking place inside the reactor.

“This means there’s a possibility of another hydrogen explosion, like Unit 1. Although yesterday’s venting was fairly successful in lowering the pressure, it’s back up to this level, so I’m saying we need to watch it.”³⁴

6:40 A.M. Yoshida warned the Head Office about the downscaling of the water level in the fuel pool at Unit 3.

“It’s been downscaling since 6:10 a.m. The fact that there’s been a sharp drop in the water level and it’s downscaling means it’s getting pretty dry, doesn’t it?

“When this happens, you know, about operations … we have a lot of people working in and around the plant. We have a lot of people here, too. We may have to think first about what we’re going to do with them, rather than operations.”

Yoshida suggested evacuating employees from Fukushima Daiichi. He said, “We’re no longer able to do anything, so is it all right to bring the field workers, our employees, back here for the moment?”

Vice President Sakae Muto at the offsite center responded:

“Of course.”

6:42 A.M. Videoconference.

Yoshida: “Please leave the field and evacuate here for the moment. What about the workers in the Central Control Room? We’d better evacuate them, too, right?”

Muto: “Well, check the level of radiation, then decide.”

Yoshida: “The dose in the Central Control Room. I’ll check what’s happening with the radiation in the Central Control Room.”

Komori: “If you evacuate the Central Control Room, you won’t be able to vent, so what should be done, including that?”

Muto: “Yoshida-san, please look closely at the dose, the dose there as well.”

Fukushima Daiichi safety team: “Regarding the dose in this room now, it’s max 28 mSv/h (0.028 millisieverts).”

Yoshida: “In here?”

Safety team: “Yes, here.”

Muto: “If it’s 28 in the ERC now, I think there’s no problem there … Yoshida-san, since things seems to have settled down a bit here, won’t you think a bit again about what to do, including work in the field?”

Yoshida: “Yes, but since there’s a fair possibility of it becoming like Unit 1, I think it’ll be extremely difficult to put people in the yard, speaking in terms of such dangerous work.”

Yoshida still asserted they had no choice but to halt field work in the “yard”—namely, the vicinity of the reactor building.³⁵

8:40 A.M., MARCH 14. Regarding the fact that Fukushima Prefecture was to announce an abnormal increase in pressure in the containment vessel of Unit 3, triggering an article 15 event in a managers’ meeting open to the press, starting at nine a.m., the prefecture requested TEPCO to go public with the facts up until that point.

Head Office officials explained to the staff onsite in a videoconference: “Both the Kantei and NISA have stopped releasing all information on this event, and they’ve asked the operators to also stop releasing information on it. This is the situation in which the prefecture is now telling us to go public.”

Nevertheless, NHK had already reported: “The pressure in the containment vessel in Unit 3 of TEPCO’s Fukushima Daiichi has risen dramatically and the operators have temporarily evacuated.” The Kantei and NISA were pushing for the release of information about the current status of Unit 3 under the judgment that “since water has already been pumped in, we fear that not releasing information would cause public anxiety.”³⁶

The person in charge at the Head Office explained the position TEPCO found themselves in. “As the operator, we should convey what the prefecture is saying. We can only get the prefecture and NISA to make adjustments … This matter comes when the state’s governance founded upon the Nuclear Disaster Special Measures Act is very strong. Of course, we can’t totally ignore the prefecture.”

“Well, the first thing to do is to inform the Kantei, let on to the Kantei. Tell them we’re in a spot, because the prefecture is telling us this.”³⁷