FUKUSHIMA, Japan — When Unit 2 began to shake, Hiroyuki Kohno's first hunch was that something was wrong with the turbines. He paused for a moment, then went back to logging the day's radioactivity readings.
He expected it to pass. Until the shakes became jolts.
As sirens wailed, he ran to an open space, away from the walls, and raced down a long corridor with two colleagues. Parts of the ceiling fell around them. Outside, he found more pandemonium.
"People were shouting about a tsunami," he said. "At that point, I really thought I might die."
EDITOR'S NOTE: It was an ordinary Friday afternoon, and then the shaking began – harbinger of a nuclear nightmare that rages on, three months later. A moment-by-moment account of the crucial first 24 hours after an earthquake and tsunami devastated Japan's Fukushima Dai-ichi plant.
Breathless, Kohno climbed a small hill and turned to look back. Black plumes rose from the reactor units. The emergency generators, burning diesel, had kicked in.
He saw the wave. It crashed over the plant's seawall, stopping only when it reached the foot of the slope about 500 yards (460 meters) from where he stood.
Kohno watched, stunned.
Unit 2, one of six reactors at the Fukushima Dai-ichi power station, is ordinary by nuclear standards: a drab labyrinth of switches and valves, ladders and bulkheads, meters and gauges. That's how Kohno, a veteran radioactivity specialist, knew it.
Now, nothing about what he saw was normal.
Kohno kept moving.
The events of the next 24 hours brought the promise of nuclear power into question, both in Japan and around the world.
Through interviews with dozens of officials, workers and experts, and hundreds of pages of newly released documents, The Associated Press found the early response to the crisis was marked by confusion, inadequate preparation, a lack of forthrightness with the public and a reluctance to make quick decisions. These problems set the tone for the troubled recovery effort since.
On March 11, Prime Minister Naoto Kan was taking a beating in an Upper House committee meeting over whether he had taken campaign money from a foreign national, which is illegal in Japan.
The questioning stopped suddenly when the entire parliament building, a sprawling structure in the center of Tokyo, started to rock. It was 2:46 p.m. All eyes rose to the huge crystal chandeliers above, clinking and shaking violently.
"Everyone, please stay in a safe position," committee chairman Yosuke Tsuruho said, grasping the armrests of his upholstered velvet chair. "Please duck under your desk."
Within four minutes, a crisis headquarters was up and running across the street in the prime minister's office. Kan rushed there as soon as the shaking subsided. At 3:37 p.m. he convened a roundtable of his top advisers.
Soon after the tsunami hit, Kan's task force was deluged by reports of massive damage up and down the coast, aerial photos and video showing entire villages gone.
Kan, who majored in applied physics in college, was among the first whose attention went to the 40-year-old nuclear plant, according to Kenichi Shimomura, a senior aide who was with him. The prime minister demanded an assessment.
The plant's operator was in disarray. Phone calls to the utility, Tokyo Electric Power Co., or TEPCO, went unanswered, and what little information trickled out was conflicting. In those critical first hours, the government was flying blind.
TEPCO President Masataka Shimizu, who was traveling, boarded a military airlift from Nagoya after he heard the news. But the flight was turned around. The Defense Ministry bumped him to free up its planes for the emergency response.
Kan quietly repeated to himself what was by now in the back of everyone's mind: "This is going to be a disaster."
On that day, Team A, a crew of 13, including a trainee, was overseeing Units 1 and 2 in one control room. In another, a crew of nine was responsible for Units 3 and 4 . The latter, along with Units 5 and 6, was offline for maintenance.
The first news was good.
All three working reactors automatically came to an emergency shutdown when the shaking began. Within one minute, all control rods were inserted properly into the cores, stopping the nuclear reactions.
What came next changed everything.
The first wave hit the plant at 3:27 p.m. At 13 feet, it was easily blocked by the plant's breakwater, which stands 33 feet above sea level.
But the one that struck eight minutes later was off the scale.
It flowed up and over the barrier, washed over a 33-foot (10-meter) water tank and tossed passenger cars this way and that. Watermarks suggest the wave may have been as high as 50 feet (15 meters).
Team A watched, horrified, as the plant deteriorated by the minute. A detailed operator's log, along with a handwritten timeline on the control room whiteboard, showed how quickly the units failed.
"15"37' D/G 1B trip," said a scribbled notation indicating the Unit 1 diesel generator went out. It was 3:37 p.m., just two minutes after the second wave had struck.
Then: "SBO." Station Blackout. The power was out.
Four minutes later, at 3:41 p.m., Unit 2 lost power. Minutes after that, key instrument readings stopped.
In the dark, workers found a main power switchboard had been submerged and a main power line brought down by a mudslide. The basement of the Unit 1 turbine building was filled with water. Two workers would later be found drowned in the basement of another turbine room.
Exactly what was happening inside the reactors remained a mystery. At 3:50 p.m., Team A wrote: "Water levels unknown." If not replenished, the water in the core would boil away and the rods would melt.
Two minutes later, Team A added an even more dire note on Unit 2: "ECCS injection not possible." The emergency core cooling system, the last-ditch backup to keep the core from going dry, was down.
It was an hour after the tsunami, and Team A desperately requested emergency power vehicles. By the time they arrived and were hooked up, it would be too late.
Outside the control room, about 755 workers, including TEPCO employees and subcontractors, were on the premises.
Yuji Sato was on break in a lounge in a small building about 60 feet (20 meters) from Unit 1, when the quake hit. He had worked all morning on the turbines.
The quake broke the air conditioner and knocked the TV in the lounge off its stand. When the shaking stopped, Sato went outside. Concrete buildings had been heavily damaged, some walls reduced to rubble.
He and about 100 colleagues streamed up the hill behind the reactors. They walked.
"None of us were all that afraid. Japan is a nation of earthquakes. We are used to them," Sato said.
His brother-in-law, pump technician Yuta Tadano, was already up the hill in a second-story office at the time of the quake. A thin young man with pierced ears and long bangs, he worked for subcontractor Tokyo Energy and Systems Inc.
Tadano wanted to go home to check on his wife, Akane, and 4-month-old son, Shoma. His boss said he expected them back at work on Monday. With the utter devastation outside the gate, the normally 20-minute drive home took four hours.
For most of the next two months, no one would be allowed inside the reactor buildings.
Still, dozens of TEPCO workers – later dubbed with some poetic license the "Fukushima 50" – stayed on. Keiichi Kakuta was one. He remained in the plant's radiation-proof Emergency Crisis Headquarters, a big, windowless conference room about 300 yards from the Unit 2 reactor.
Although it meant leaving his family in Tokyo, Kakuta had jumped at the chance for a public affairs job with TEPCO in Fukushima three years ago. He had always admired the company's teamwork and looked forward to a new challenge.
He got the biggest of his life.
By late afternoon, Unit 1 was spiraling out of control, with its power and cooling systems down.
The heat from decaying radioactive elements in the fuel rods was growing. As the core overheated, it burned off its coolant water, exposing the 13-foot (4-meter) rods. In turn, steam from the evaporated water was building up inside the containment chamber.
As the heat and pressure rose, the uranium pellets inside the rods melted through their zirconium casings. When the zirconium reached 2,200 degrees Fahrenheit (1,200 Celsius), it reacted with the water, producing hydrogen.
This was obviously going to get worse before it got better.
Yukio Edano, the chief Cabinet spokesman, is the face of Japan's government. At 7:45 p.m., his job was to make an unprecedented statement to the nation – but make it sound routine and reassuring.
"We have declared a nuclear emergency," he said from behind a podium in the press conference room at the prime minister's office. "Let me repeat that there is no radiation leak, nor will there be a leak."
He was wrong. Recently released TEPCO documents reveal that radiation was detected at the plant perimeter at 5:30 p.m., but the utility apparently didn't fax those readings to the government until shortly after 9 p.m.
In the meantime, a two-mile (three-kilometer) evacuation zone around the plant was established. That later would become 6 miles (10 kilometers), then 12 (20). In the end, more than 80,000 people would be forced to flee.
Fukushima Dai-ichi's operators, meanwhile, were faced with a twofold response: Vent and flood. Venting to release pressure and prevent an explosion, flooding to keep things cool.
But venting would release radioactivity into the air. And flooding with seawater would ruin the equipment because of the salt.
Around 9 p.m., less than six hours after the tsunami, officials at the prime minister's office started to press TEPCO to vent. TEPCO hesitated.
Fukushima Dai-ichi was the utility's golden goose. Designed primarily by General Electric, it went online in 1971 and had kept the lights shining in Tokyo ever since. Unlike newer facilities, it was paid for, and it was generating profits with each megawatt it produced.
TEPCO knew that venting radioactivity would cast doubt on the safety of the nuclear industry around the nation, and the world. But the options were dwindling.
The outage of primary and backup power – a scenario that exceeded planners' precautions – was severely hampering operations.
The first emergency power vehicle sent by TEPCO got stuck in the chaotic post-tsunami traffic. A backup truck from another power company arrived at 11 p.m., but the cable it brought was too short to hook up.
At 3:05 a.m., Trade and Industry Minister Banri Kaieda trotted out TEPCO executive Akio Komori for a public announcement of the plan to vent the Unit 1 containment vessel. Seven minutes later, Edano took to the podium, this time to warn the public that the action would entail the release of radioactive isotopes. Again, he urged calm.
For those who knew what was happening, the urgency was mounting. The containment chamber around the core was bulging with pressure twice as high as its maximum operational limit and nearly matching the company's required venting standard.
"We kept telling TEPCO to do it quickly, asking how come it wasn't happening," Edano recalled later.
Nearly four hours after the initial announcement, an exasperated Kaieda ordered TEPCO to vent. It was 6:50 a.m.
Surging radiation forced workers to abort their attempt to open the valves manually. Then they tried to open them remotely and repeatedly failed, probably because of the power outage but possibly also a design flaw. The equipment had never been used in a real-world crisis.
Unit 1 was a ticking time bomb.
As the night wore on, the prime minister decided he had to go to Fukushima himself, at first light. His helicopter landed at 7:11 a.m. on March 12. Like everyone else in the entourage, Kan wore a blue-gray work uniform and had a dosimeter hanging around his neck.
His aide, Shimomura, a former TV journalist, was assigned to chronicle the event. He started filming as the group boarded a minibus bound for the emergency crisis headquarters.
It looked normal enough from the outside. Inside, though, was a madhouse. Dozens of workers raced back and forth, trying not to step on about 20 others either slumped to the floor or sleeping in blankets in the hallway.
Shimomura turned off the camera. This scene would not reassure the nation, or the world.
Escorted by TEPCO officials, Kan strode past men so preoccupied or tired that they didn't even acknowledge the presence of their country's leader.
Kan, known for his short temper, fired questions at plant executives and pointed at diagrams of the reactors on a sheet of paper in front of them. He yelled at TEPCO Vice President Sakae Muto and plant chief Masao Yoshida, his onsite escorts, demanding to know why the venting and seawater injection were not happening.
The discussions lasted only half an hour. At 8 a.m., Kan was on his way back to Tokyo.
By then, TEPCO would later acknowledge, the core at Unit 1 had mostly melted, and units 2 and 3 were not far behind.
At 2:30 p.m., workers burst into applause. Vapor was rising from the Unit 1 stack and containment vessel pressures fell – confirmation that the venting was working. But within half an hour, they ran out of fresh water.
This was what TEPCO had dreaded.
Fukushima Dai-ichi was built right next to the biggest source of water on the planet – the Pacific Ocean. Pumping water out of the ocean is an absolute last resort, however. The reactors would never be usable again.
Yet again, TEPCO officials waffled. At 3:36 p.m., almost 24 hours to the minute after the second tsunami hit, the hydrogen inside Unit 1 combined with oxygen already there and exploded, in a fiery blast that blew off the roof and sent a plume of contaminated smoke and debris into the sky.
The decision to use seawater was unavoidable.
Blasts at units 2, 3 and 4 would follow in the coming days. TEPCO's primary task, and for months or even years, is still to repair the damage from the explosions.
Japan's nuclear nightmare had begun.