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| a 10-seat Super Puma military helicopter carrying Mr. Kan and several aides landed at the plant. |
So helpless were the plant's engineers that, as dusk fell after Japan's devastating March 11 quake and tsunami, they were forced to scavenge flashlights from nearby homes. They pulled batteries from cars not washed away by the tsunami in a desperate effort to revive reactor gauges that weren't working properly. The plant's complete power loss contributed to a failure of relief vents on a dangerously overheating reactor, forcing workers to open valves by hand.
And in a significant miscalculation: At first, engineers weren't aware that the plant's emergency batteries were barely working, the investigation found—giving them a false impression that they had more time to make repairs. As a result, nuclear fuel began melting down hours earlier than previously assumed. This week Tokyo Electric Power Co., or Tepco, confirmed that one of the plant's six reactors suffered a substantial meltdown early in Day 1.
Late Monday in Japan, Tepco released more than 2,000 pages of documents, dubbed reactor "diaries," which also provide new glimpses of the early hours. Soon after the quake, but before the tsunami struck, workers at one reactor actually shut down valves in a backup cooling system—one that, critically, didn't rely on electrical power to keep functioning—thinking it wasn't essential. That decision likely contributed to the rapid meltdown of nuclear fuel, experts say.
The Journal's reconstruction is based on examination of Tepco and government documents, along with dozens of interviews with administration officials, corporate executives, lawmakers and regulators. It uncovered new details on how Tepco executives delayed for seven hours before formally deciding to vent a dangerous pressure buildup in one reactor, despite an unusual face-to-face clash between Japanese Prime Minister Naoto Kan and Tepco top brass.
Tepco executives have acknowledged they weren't aware for hours of the severity of the crisis. By the time Tepco decided to vent its reactor, radiation levels were so high that the man who volunteered to hand-crank the relief valve open was exposed, in a few minutes, to 100 times the radiation an average person gets in a year.
The government itself, despite Mr. Kan's hands-on involvement, failed to come up with a unified early response of its own. Not only were officials tripped up by overly optimistic assessments of the situation, but their own emergency-response building was without electricity and phones.
"There was a lack of unity," said Goshi Hosono, the cabinet official overseeing the Fukushima disaster.
When a magnitude-9 quake struck at 2:46 p.m. on March 11, many of Fukushima Daiichi's managers were in a conference room at the plant for a meeting with regulators. They were just wrapping up when the ground shook, says Kazuma Yokota of the Nuclear and Industrial Safety Agency, or NISA, Japan's nuclear regulator. Files toppled over. Walls and the ceiling cracked, sprinkling a fine, white dust.
The electricity died. Mr. Yokota, a thin man with a quick, nervous laugh, recalls someone saying: "Wow, that was bad."
But the emergency appeared under control. Fukushima Daiichi's three active reactors went into automatic shutdown, called a "scram." And the backup diesel generators kicked in, powering emergency lights and a cacophony of alarms.
Then, almost exactly one hour later, a tsunami roughly 50 feet high struck, killing the emergency generators.
At 3:37 p.m., Teruaki Kobayashi, a Tepco nuclear-facilities chief in the company's Tokyo war room, remembers Fukushima Daiichi calling in a "station blackout." One of Japan's largest nuclear plants had just gone dark.
"Why would this be happening?" Mr. Kobayashi recalls thinking. A full blackout is something only the worst-case disaster protocols envision.
His next thought was that the plant still had an eight-hour window to restore power before things really turned bad. That's how long the plant's backup batteries, its final line of defense, were supposed to last, cooling the reactor fuel rods and powering key instruments.
When a magnitude-9 quake struck at 2:46 p.m. on March 11, many of Fukushima Daiichi's managers were in a conference room at the plant for a meeting with regulators. They were just wrapping up when the ground shook, says Kazuma Yokota of the Nuclear and Industrial Safety Agency, or NISA, Japan's nuclear regulator. Files toppled over. Walls and the ceiling cracked, sprinkling a fine, white dust.
The electricity died. Mr. Yokota, a thin man with a quick, nervous laugh, recalls someone saying: "Wow, that was bad."
But the emergency appeared under control. Fukushima Daiichi's three active reactors went into automatic shutdown, called a "scram." And the backup diesel generators kicked in, powering emergency lights and a cacophony of alarms.
Then, almost exactly one hour later, a tsunami roughly 50 feet high struck, killing the emergency generators.
At 3:37 p.m., Teruaki Kobayashi, a Tepco nuclear-facilities chief in the company's Tokyo war room, remembers Fukushima Daiichi calling in a "station blackout." One of Japan's largest nuclear plants had just gone dark.
"Why would this be happening?" Mr. Kobayashi recalls thinking. A full blackout is something only the worst-case disaster protocols envision.
His next thought was that the plant still had an eight-hour window to restore power before things really turned bad. That's how long the plant's backup batteries, its final line of defense, were supposed to last, cooling the reactor fuel rods and powering key instruments.
Tepco engineers now believe the tsunami knocked out most, if not all, of the batteries, according to documents from Tepco on Monday. But they didn't know that then. They thought the batteries were still working, giving them the eight-hour cushion.
Word of the station blackout reached Mr. Kan quickly, at 3:42 p.m. in the prime minister's Tokyo "war room" working on quake emergency response. According to two people present, when Mr. Kan heard about Fukushima Daiichi, he said, "The real trouble is at the nuclear plant."
Officials started dispatching military and medical personnel, as well as emergency generators.
As dusk approached at Fukushima Daiichi, engineers used the scavenged car batteries to power makeshift gear to try to understand what was going on inside the reactors. At 9:21 p.m., they took an alarming reading: The water level in Reactor 1 had dropped so sharply that its fuel rods were about to be exposed.
Without a cooling system, the water boils off, building up dangerous pressure inside the reactor. If enough water boils off, nuclear rods can melt and react with the air, releasing radioactive elements and producing explosive hydrogen gas.
Around 11:00 p.m., the first power-supply trucks arrived, prompting cheers in Mr. Kan's Tokyo office.
The celebration was premature. Tepco workers couldn't hook the generators to the plant's damaged main switches. Some cables were too short to reach other parts of the facility. Tsunami warnings forced workers to retreat to higher ground.
During the first 24 hours, only one generator was successfully hooked up, Tepco documents show.
Around midnight, pressure within the vessel containing Reactor No. 1 had already exceeded its design maximum by 50%. Radiation levels were so high that Tepco president Masataka Shimizu ordered workers to stay away from the building.
It was becoming clear both to Tepco and the government that a dramatic step had to be taken: Vent the gas in the reactor before the containment vessel cracked under pressure, according to administration officials.
Venting has risks. The gases are likely to be radioactive and could endanger nearby communities. But without venting, the risk of catastrophic destruction of the vessel seemed too great. Mr. Kan and Banri Kaieda, the minister in charge of the power industry, gave their official blessing to vent around 1:30 a.m.
What followed were hours of miscommunication and confusion. By 2:45 a.m. March 12, Tepco had told NISA that pressure in the vessel containing Reactor 1 was already likely double the design maximum.
Still, its vent remained closed. From the prime minister's office, Mr. Kaieda called Tepco executives hourly to check on progress. At 6:50 a.m., he formally ordered Tepco to vent, still without result.
Tepco disclosed this week that it now believes that, by this time on the morning of March 12, the nuclear fuel in Reactor 1 had already melted into a heap at the bottom of the reactor vessel.
Government officials now say it took Tepco so long to decide to vent because the radiation release would sharply elevate the accident's severity. They say Tepco still hoped the accident could be contained without venting, given that release of radioactivity in the atmosphere would instantly rank Fukushima among the world's worst accidents, along with Chernobyl.
In subsequent press conferences and parliamentary testimony, Mr. Shimizu, Tepco's president, attributed delays to concern about evacuating residents and technical problems. Tepco declined to make Mr. Shimizu available for comment.
As daybreak approached on March 12, Mr. Kan flew to Daiichi to prod Tepco officials in person. Around 7 a.m., a 10-seat Super Puma military helicopter carrying Mr. Kan and several aides landed at the plant.
Once the group entered the emergency bunker there, a Tepco staffer tested their radiation levels with a Geiger counter. A plant worker entering at the same time registered a reading so steep it prompted the tester to exclaim, "Wow! It's really high where you were," an aide recalls.
In a small room with two rows of gray conference tables, Mr. Kan sat across from Sakae Muto, Tepco's nuclear chief, and Masao Yoshida, the plant manager.
Mr. Kan clashed with Mr. Muto, a tall nuclear engineer with a mane of white hair, according to people present. Mr. Muto said the plant's power problems meant venting couldn't start for at least another four hours. Tepco was considering sending in workers to open vent valves by hand, Mr. Muto said, but radiation levels near the reactor were already so high that executives weren't sure they wanted to do that. They would decide in an hour, Mr. Muto said.
"It's tough to line up enough people to do the job" of venting, Mr. Muto said, according to a Kan aide.
"This is no time to dilly-dally. Do it fast, whatever way you can!" Mr. Kan yelled at Mr. Muto, according to people present.
A Tepco spokesman declined to make Mr. Yoshida or Mr. Muto available for comment, and said he wasn't able to confirm Mr. Muto's remarks. He said the company has always been eager to use help from the government and others to contain the accident.
Mr. Kan left Daiichi shortly after the meeting. At 8:18 a.m.—seven hours after the plant's engineers had first told Mr. Kan and other officials that they wanted to vent Reactor 1—Tepco informed the prime minister's office it would start opening the valves in just under another hour's time.
Despite the extreme delay, the relief valves could still be opened. The problem: Normally they would be operated the safety of the control room, either by electric motors, or by compressed air. But those systems weren't working.
As a result, they would have to be opened by workers braving high radiation levels inside the reactor building itself. The staff battled four hours to open the pneumatic valve, succeeding only after carrying in a portable air compressor in shifts.
For the motor-driven valve, there was only one option: Crank it open by hand. Fukushima Daiichi's shift manager decided it was his responsibility to take the first crack at that, Fukushima prefectural officials recall. "Let me be the one," he said, according to the officials.
He went in wearing full protective gear, including a mask and an oxygen tank. Even so, by the time he returned, he'd gotten a 106.3 millisievert dose of radiation, these people say. That's more than twice what Japan normally permits for workers in radioactive environments in one year, and more than one hundred times normal annual exposure. (by WSJ)
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