Читать книгу Meltdown - Yoichi Funabashi - Страница 21

10:00 P.M., MARCH 11. Teresaka brought a slip of paper to the Kantei, on which “Unit 2, meltdown at 27:30” was written. This was the recalculation NISA had made from the report TEPCO had filed with them at 9:15 p.m. on the situation in Unit 2. According to this,

Around 10:20 p.m., March 11	Core damage initiation
10:50 p.m., March 11	Core exposed
12:50 a.m., March 12	Fuel melting
3:20 a.m., March 12	Highest design specification of pressure in the reactor containment vessel (527.6 KPa) reached 56

Nuclear power fuel came in the form of uranium oxide, which sintered at high temperature to produce pellets about the size of a cigarette filter. The fuel rods consisted of these pellets encapsulated in zirconium alloy-clad tubes. During operation, the fuel rods are cooled with water, but if they cease to be cooled, the temperature of the fuel rods rises, melting the cladding tubes and, in turn, the pellets. This amounts to core damage. Terasaka touched on the possibility of core meltdown when outlining the situation forecast as of 3:20 a.m. on March 12.

“Is it going to meltdown?!”

Kan raised his voice.

“It may not go that far straight away.”

“But that’s what’s written here.”

Kan’s mistrust of Terasaka instantly grew stronger. What is he talking about? Kan wondered.⁵⁷

After one p.m. on March 12, Kan, Edano, and Kaieda were briefed in a meeting in the prime minister’s office by Mitsuhiro Kajimoto, deputy manager of the Nuclear Power Safety and Evaluation Division at the Japan Nuclear Energy Safety Organization (JNES). Hiraoka also attended. The topic was “What Measures Should Be Taken if the Venting at Unit 1 Failed.” NISA had already conducted a simulation and started considering countermeasures.⁵⁸

Kajimoto was an expert in emission predictions of radioactive substances in the case of severe nuclear accidents. His doctoral thesis had been “Research on the Behavior Analysis of Radioactive Material in a Core Damage Accident at a Light Water Reactor Type Nuclear Reactor Facility.” He had also previously worked in the risk assessment analysis laboratory of the Japan Atomic Energy Research Institute.

At four p.m. on the previous day, March 11, he had been summoned to the Emergency Response Center and stayed there.

Sometime after nine p.m., Kajimoto was asked for his opinion concerning “the prediction of changes in the future development of the accident” during a videoconference with NISA and the NSC. He replied, “There is an extremely strong possibility of core damage in Reactors No. 1, 2, and 3.

“There is also a possibility that, if things continue as they stand, the pressure vessel will be breached in several hours.

“If no measures are taken, it is likely that the containment vessel will be damaged.”

Yutaka Kukita, acting chairman of the NSC, asked him, “Do you think the fuel pool at Reactor No. 4 is all right?”

“It needs to be watched, but probably doesn’t need to have immediate action taken. You have to deal with Reactors No. 1, 2, and 3 first. But measures will be needed at some stage.”

Kajimoto and the engineers at JNES had predicted the radiation emission amount, if venting took place, based on the results of past venting simulation analyses.⁵⁹

In the meeting in the prime minister’s office from one p.m. on March 12, Kajimoto handed out a single piece of paper outlining the scenario if the venting operation failed.

Noble gas	100%
Iodine	10%
Cesium	1%

It was the analysis results of emission volumes some ten hours later. Kajimoto told Kan, “The time it will take the pressure in the containment vessel to reach three times its regular level is the yardstick we have used.”

“What do you mean by three times of that?”

“I mean the possibility that the containment vessel will be damaged.”

“Well, spit it out then, man!”

Kan’s voice was raised. Just as the briefing was coming to an end, NTV News 24 started broadcasting a press conference with officials from NISA and the NSC.

“There is a possibility that meltdown is in progress. We are almost certain that meltdown is in progress.”

Kan bellowed, “What’s this?!”

“What on earth is this?”

“No one’s told me this.”

Kan questioned Hiraoka, “What’s the meaning of this?”

Edano also asked, “None of what they’re saying at the press conference has been through the Kantei?”

Hiraoka bowed his head in apology. “I’m sorry. I’m sorry.”⁶⁰

In a building some fifty meters high, there is a flask-shaped containment vessel, which houses the pressure vessel. Inside the pressure vessel, the reactor core with its fuel rods is submerged in water. The heat generated by the fission reaction of the fuel turns that water into vapor, which passes through tubes to turn the power turbines. The water vapor is then cooled with seawater, which turns it back into water and is fed back into the pressure vessel. If something goes wrong with this cycle and the reactor core is not cooled down, meltdown occurs.

The term “meltdown” refers to a severe accident where the fuel rods melt due to an inability to cool the core. If left unattended, there is a very strong danger that not only the pressure vessel but the building’s concrete floor would melt, releasing large amounts of radioactive material.

Just before the press conference on the afternoon of March 12, Deputy Director General for Nuclear Safety Koichiro Nakamura reported to Terasaka at the Emergency Response Center at NISA.

“The monitoring value onsite at Fukushima Daiichi Station is rising. A considerable amount of time has also passed since the loss of AC power, and it is inconceivable that the emergency isolation condenser (IC) is working. The tops of the fuel rods continue to be uncovered above the water level. Since the water level is still falling, there seems to be a strong possibility of meltdown at Unit 1.”

In the morning of that day, cesium was detected in the area around Fukushima Daiichi Station. Nakamura deemed it “fair to say that the fuel in the reactor core was melting,” and reported this to Terasaka as well. If the radioactive material was rare noble gas and iodine, you could well say that there was a leak, but with solid particles like cesium being detected, it was necessary to assume a situation in which the containment vessel had been damaged.

If a substance that only existed in the pellets was detected outside the building, the only possibility was a meltdown. Terasaka told Nakamura, “[If that’s the case,] there’s nothing for it but to say so.” This was why, having mentioned this point in the press conference, Nakamura used the straightforward expression “the possibility of meltdown.”

That was the exchange leading up to Nakamura’s appearance at the press conference. As has already been seen, he had conveyed the same information to the Kantei the night before. But his message never made it to Kan or Edano. They were both amazed to hear Nakamura’s remarks. Edano was outraged about facts that had not been reported to the Kantei, which came to light for the first time at a TEPCO and NISA press conference.

“It’s an unthinkable situation that the Japanese people have the information before the Kantei!”

Madarame, who was on the fifth floor of the Kantei, remembers clearly what the situation was in the Kantei at the time.

“I think it was Edano-san who was hopping mad that NISA seemed to know more than the Kantei, and the one thing I remember clearly is that he said, ‘It’s an affront not to tell the Kantei first!’ ”

One of the technical staff encamped on the fifth floor of the Kantei stated that he had come across Edano at the time, walking by at a brisk pace and issuing instructions to his aides, “Don’t let NISA talk as they please” and “Make them report beforehand.”⁶¹

Edano was not the only person dissatisfied with how NISA was passing on information. The prime ministerial secretariat and the chief cabinet secretary secretariat were equally distrustful. Keisuke Sadamori, secretary to the prime minister, requested NISA to “submit to the Kantei in advance any NISA press announcements on the reactor meltdown.” The Kantei sent the word out that “all announcements to the Japanese people were to be disseminated via chief cabinet secretary press conferences only.” An internal memo from NISA, time-stamped 3:23 p.m., noted: “We’ve been asked to contact the Kantei before going public with any announcements on meltdowns.”⁶²

Nakamura was in charge of the press announcements until 5:50 p.m., after which he asked Terasaka whether he could be relieved of his position as PR official. Terasaka ordered a change in personnel. The 5:50 p.m. press conference was the last one at which Nakamura acted as NISA spokesman. He was replaced by Tetsuo Noguchi, NISA deputy director general.

In the 9:30 p.m. press conference on the same day, Noguchi stuck from start to finish with the ambiguous phrase “I don’t think that the statement [regarding core meltdown] was based on a clear assessment of the situation.” In a further press conference in the early hours of March 13, Deputy Director General Hisanori Nei appeared as the spokesman, saying, “I have taken over at the direction of top management.”

Nei avoided the term “meltdown,” using instead the statement “the possibility of fuel rod damage cannot be denied.”

On the evening of March 13, Nei was replaced with Deputy Director General Hidehiko Nishiyama making his debut. Nishiyama also showed an aversion to the word “meltdown,” displaying his mastery of rhetoric with “the appropriate expression is ‘damage to the external cladding of the fuel rods.’ ” (It was only on April 18 that NISA acknowledged a meltdown.)

During this time, the Kantei did not instruct NISA not to use the term “meltdown.” There is no evidence that Chief Cabinet Secretary Edano intervened directly in NISA personnel decisions. Nor is there any evidence that they applied pressure to avoid the term “meltdown.” Regarding this point, Edano later revealed, “I issued a strict order that if they were to announce something in a press conference, they should at least report it simultaneously to the Kantei.”

Touching on the fact that “this instruction to report simultaneously” was distorted into “press conferences require the approval of the Kantei,” he wrote: “While it is regrettable that the instructions were not carried out thoroughly, I am convinced that the instructions themselves were correct.”

When queried about the possibility of a meltdown in Unit 3 in a press conference from eleven a.m. on March 13, Edano responded: “There is a real possibility of that, and since we cannot confirm what is happening inside the reactor, we are, as a matter of course, taking measures on that assumption.”

There is also no sign that METI Minister Banri Kaieda intervened. Permanent Secretary Kazuo Matsunaga did not make a move, either. Conversely, Matsunaga said, “Release what information you have as soon as possible.” His assessment at the time of Nakamura’s statement was that “it was right.”

What is probably the closest to the truth is that Terasaka, guessing at the “intention” of the Kantei, had Nakamura removed. Terasaka had instructed Sakurai to pass on to Nakamura that “there were those who had expressed alarm at the nature of the statements at NISA press conferences, so be careful what you say in any press announcements.” A senior official at NISA spat out: “He [Terasaka] overreacted.”⁶³

The removal of Koichiro Nakamura not only had NISA worried, but all of Kasumigaseki. Was the Kantei going to micromanage all the factual reporting? Was that not really the job of the officials and people in charge who were closest to the frontlines? Was not the job of the Kantei to make political judgments on what needed to be done based on the affirmed facts of the situation?

“Did you pass it on up to the Kantei?”

“Does the Kantei know about this?”

“Shouldn’t you leave that with the Kantei?”

NISA, METI, MEXT, MHLW—everyone was highly sensitive to keeping the right distance with the Kantei. The submission process for information—that is, the “paperwork”—to the Kantei took a huge amount of energy. It was not permissible for “the Kantei to know, but not the permanent ministerial secretary.” Almost every government ministry and agency had their rules for submitting information to the Kantei.

“It was all very time-consuming, passing papers around and sometimes waiting for the all-clear before taking it off to the Kantei,” said a senior METI official.

During this time, around two p.m. on March 13, Shimizu visited the Kantei along with Komori and others. However, only Shimizu met Edano in the cabinet secretary’s office. After returning to Head Office, Shimizu told a director at TEPCO that from then on, TEPCO should seek the Kantei’s approval in advance for press release drafts or material they intended on sharing with the public for press announcements.⁶⁴

TEPCO workers onsite knew that things were moving quickly toward a meltdown. As the reactor manufacturer, Toshiba had reported them as such while sending TEPCO findings as they came from its Isogo Engineering Center, TEPSYS, a subsidiary of TEPCO specializing in core damage analysis. All of the analytics predicted the development of a meltdown. No one knew this better than TEPCO Vice President Sakae Muto. Reactors were his “turf,” and so knowledgeable was he that everyone clammed up if he said anything about “reactor physics.”

However, both TEPCO and NISA avoided using the term “meltdown” as if it were a taboo word. In the afternoon hours of March 12, Akiyoshi Minematsu, who served as a technical adviser to TEPCO officials in the company’s emergency and disaster response team, received a call from TEPCO Fellow Ichiro Takekuro at the Kantei. It was his first call from the Kantei since the nuclear crisis had begun. “Kantei is telling us not to use the word ‘meltdown.’ ” Minematsu responded, “It isn’t inaccurate to say that the reactor core is damaged, so why should we say it is?”

Minematsu later testified that “If one says ‘meltdown,’ people will think of the China Syndrome, so we were a bit uncomfortable with using that word.”⁶⁵

During this time, Shimizu was preoccupied with thinking of ways to “stay on the same page” as the Kantei. In the evening of March 14, during an in-house teleconference, a TEPCO employee at the Head Office’s Emergency Response made the following remark to a reporter: “I would like to answer by saying that we acknowledge there is fuel damage.” Shimizu interrupted and said, “Regarding that … be sure to, you know, with them and the Kantei beforehand.” It was difficult to discern exactly what Shimizu meant, since he kept repeating “that,” but everyone who heard it understood that he wanted them to report to the Kantei and seek their approval before making announcements to the press. In particular, he wanted everyone to be careful when acknowledging a “reactor core meltdown” to the outside world.⁶⁶

From March 15 on, TEPCO always used the expression “core damage” when explaining the condition of the core at press conferences.⁶⁷ Employees at TEPCO’s affiliates were aware of this “fear” of the Kantei. Cautions like the following came down the line from top management to the manufacturers in the field:

“Don’t use the word ‘meltdown’—it’s too provocative. Don’t say ‘melted’; say ‘melting.’ ”⁶⁸

In June 2012, TEPCO announced in their Fukushima Nuclear Power Plant Accident Investigation Report the time “reactor core damage” occurred:

 Unit 1, around 6:50 p.m. on March 11

 Unit 3, around 10:40 a.m. on March 13

 Unit 2, around 7:20 p.m. on March 14

Compared with TEPCO’s initial assessment that the damage for Unit 1 occurred around six a.m. on March 12, and for Unit 2 around four a.m. on March 16, the dates and times indicated in this report are roughly eleven and thirty-three hours earlier, respectively.⁶⁹