When Kenji Tateiwa applied to Stanford GSB, he described in the essay "what matters most" to him: his "dream of establishing a perfect energy world." He never thought he would have a chance to apply his expertise in nuclear engineering to a severe nuclear accident.
Tateiwa studied nuclear engineering at Kyoto University and had worked for Tokyo Electric Power Company, or TEPCO, since he graduated in 1996. His career included a stint at the Fukushima Daini nuclear power plant, a sister plant to the one that was severely damaged by the tsunami in March 2011.
That accident "almost shattered my belief in nuclear" power, Tateiwa, MBA '04, told a recent gathering of 110 Stanford alumni and students at the business school. But he said he was heartened by the post-accident recovery, including the international support with crisis management that the company received.
"I realized that mankind still needs to rely on nuclear power to a certain degree, but we need to make it safer," said Tateiwa, who is currently manager of nuclear power programs for TEPCO.
Support from U.S. experts who were involved in the Three Mile Island accident underscored "the critical importance of the U.S.-Japan relationship," Tateiwa said after the talk. However, he added, "more global talent is necessary who can bridge the cultural and language barriers and effectively cope with emergency situations like this."
When the earthquake struck at 2:46 p.m. on Friday, March 11, Tateiwa was just getting off the metro in Tokyo. He felt shaking and, when he got outside, he saw skyscrapers shaking. The earthquake measured 9.0, the strongest ever recorded in Japan. The resulting tsunami, which left 20,000 people dead or missing, was also the largest ever recorded in Japan.
For the first few days, Tateiwa worked on translating press releases for an international audience. Later, he visited ambassadors from other countries to update them. "They needed to know whether it was safe being in Japan or not," he said.
In the weeks after the accident, Tateiwa made several visits to the Fukushima Daiichi site. On his first visit, on April 6, he coordinated a visit from the International Atomic Energy Agency, wearing a full face mask. The company was "still in crisis mode," unsure if the reactors were stable, he said. When he returned to the site in May, he slept in the "bedroom" of the emergency response center, getting a few hours of sleep at a time on the floor.
TEPCO's emergency responders faced multiple challenges. At the Fukushima Daiichi plant, although the earthquake did not cause any damage to safety-related equipment, and seismic acceleration exceeded the plant's design limits only in isolated locations, the tsunami reached 43 feet, far exceeding the 20 feet the plant was designed to withstand. Most of the plant's major buildings were severely flooded.
"This was a black swan event that was beyond what we had postulated," he said.
At the nearby Fukushima Daini plant, the damage from the tsunami was less extensive, but flooding still made it difficult to achieve a cold shutdown.
Nuclear power plants produce heat from nuclear fission during operation, but they also keep producing heat from radioactive decay after a plant is shut down. For this reason, emergency cooling systems are crucial. In an emergency, the reactor needs to be shut down and then cooled. After that, the priority is to contain the radioactive materials.
All operating reactors did shut down as they were supposed to after the earthquake, but then the tsunami knocked out even the backup generators for the emergency cooling systems. "We had multiple means of injecting water into the reactor, but most of them relied on power," Tateiwa said.
Workers at the Fukushima Daiichi plant had to contend with near-complete darkness, increasing radiation levels and flooding. Obstacles on the road made access to the plant difficult. The only way to communicate between the main control room — where instruments were not working because of the power outage — and the emergency response center was using one fixed phone line.
To recover the instrumentation needed to assess the situation, workers took batteries from cars in the parking lot and carried them in the dark to the plant. Every time an aftershock happened — and there were 155 of magnitude 5 or higher on the first day alone — they would have to run to high ground in case of another tsunami.
To vent steam through two critical valves that could not be opened remotely when the power went out, teams carrying radiation alarms walked through the plant to open the valves manually. One team was successful, but another had to turn back when the radiation level got too high. At the less heavily damaged Fukushima Daini plant, workers had to lay 9 kilometers of temporary cables to bring the units to a safe, cold shutdown.
In all, they had ten simultaneous reactor accidents at the two sites. In the days after the accident, workers were able to achieve a cold shutdown of six of the reactors; three of the others' buildings exploded during that time. Tateiwa said workers at the plants volunteered for hazardous, potentially fatal, duty to get the plants into a safe condition.
International support was also helpful, he said. Beginning in late March, a U.S. industry group called the Institute of Nuclear Power Operations sent its industrial support team, a group of 10 specialists including some who had experience with the accident at Three Mile Island. They answered questions and provided invaluable advice at TEPCO's Tokyo headquarters.
Tateiwa pointed out that although the tsunami killed 20,000 people, no injuries or deaths have been reported as a result of the radiation from the nuclear power station. TEPCO has completed a 500-page report on the accident; an English translation is in progress. In September 2011, Tateiwa moved to TEPCO's Washington office, where he now works.
Tateiwa concluded his talk by taking questions from the audience. Several of them focused on the viability of nuclear power in light of the accident; one questioner asked whether nuclear power was dead.
"Personally I don't think it's dead," Tateiwa said. "I don't think it should die." However, he added, alternative energy sources are needed for the long term.