Fukushima: The Story of a Nuclear Disaster

by David Lochbaum

  Martin Virgilio, the NRC’s deputy executive director for reactor and preparedness programs, was manning the Operations Center at White Flint and had just gotten off the phone with nuclear industry officials. They had provided new information that Virgilio, a level-headed thirty-four-year veteran of the NRC, wanted to pass along to Jaczko by phone.

  Virgilio’s information had come from the Institute of Nuclear Power Operations (INPO), an industry group created after the Three Mile Island accident to bolster nuclear safety initiatives and enhance the industry’s tattered public image. INPO, and its international counterpart, the World Association of Nuclear Operators (WANO), had been working sources to learn as much as possible. (One valuable source for the industry and the NRC was Chicago-based Exelon Corporation, which operates more boiling water reactors than any other U.S. utility.) The call provided the NRC with important details, including information gleaned by industry people directly from their contacts at TEPCO. Not all of the information, however, was accurate.

  INPO and WANO representatives told Virgilio that a hydrogen explosion had occurred in the Unit 1 reactor building, confirming the assessment of NRC staff members who had watched the explosion on television. It was a significant detail. If the explosion was in the turbine building, the hydrogen could easily have come from sources other than damaged fuel in the reactor core and/or spent fuel pool. But if the reactor building exploded, it was a far more likely indicator of extensive fuel damage somewhere.

  As the industry representatives and the NRC shared what they knew, they pieced together this picture of the situation at Fukushima Daiichi: after the explosion, radiation levels at the plant boundary had jumped to one hundred millirem (one millisievert) per hour—about ten thousand times background—but then dropped to fifty millirem per hour. The primary containment at Unit 1 was believed to be still intact. Iodine and cesium isotopes had been detected, indicating some melting of fuel. About eight inches (twenty centimeters) of the fuel in Unit 1 had been partially exposed, and maintaining water levels in that reactor vessel was problematic. There was an unconfirmed report that the Unit 1 containment was being filled with borated seawater using fire trucks. Unit 3 appeared to be in cold shutdown. Unit 2’s RCIC cooling system seemed to be doing its job of transferring heat from the core to the torus, but there was no electrical power to run the pumps that cooled the torus water and transferred heat to the sea. If heat could not be removed from the torus water, the containment temperature and pressure would continue to rise.

  Although trouble seemed to be brewing at Unit 2, the Unit 1 situation topped everyone’s list of concerns. And in hindsight, they were not wrong—Unit 1’s damage was actually far more extensive at that point than the briefing had indicated. However, the worsening conditions at the other two units, as well as Unit 4, would soon vie for the NRC’s attention.

  For the NRC, the fragmentary information spilling out of Japan posed a combination of challenges the staff had never encountered during emergency drills; nobody had trained for an event this severe. The experts at White Flint and elsewhere within the agency were largely forced to rely on secondhand information and computer analyses that might not have accurately reflected what was actually happening. At the same time, the NRC, as home to the U.S. government’s resident experts in nuclear power, was being counted on to provide guidance to ensure the safety of Americans scattered all over Japan, including 38,000 U.S. troops, 43,000 dependents, and 5,000 civilian defense employees, plus embassy personnel, businesspeople, students, and tourists.

  One of Jaczko’s main concerns, even at that early stage, was the potential radiological impact of the accident and how far away from the site significant radiation exposure could occur. The NRC’s Protective Measures Team had already begun to run computer simulations, using a code called RASCAL (the Radiological Assessment System for Consequence Analysis) to address this question. However, as was the case with SPEEDI, the RASCAL simulations were of limited value without data on how much radiation was actually being released. Virgilio told Jaczko that, based on crude assumptions, including a total failure of the Unit 1 reactor containment and severe core damage, the exposure levels that would trigger evacuation by U.S. standards would be exceeded at fifty miles from Fukushima.3 Jaczko asked if there could be danger even farther away and Virgilio said the NRC hadn’t modeled past that point. He didn’t mention to Jaczko that the RASCAL code was only good out to fifty miles.

  In addition to monitoring what was happening in Japan, the staff at the Operations Center was beginning to focus on a different kind of crisis: a potential public relations nightmare at home. The NRC oversees twenty-three reactors of the same design as the units in trouble at Fukushima Daiichi. The agency had been dragging its feet for years on addressing a host of difficult issues, including revising seismic safety rules. And now the NRC faced the unpleasant task of having to defend its oversight before a newly skeptical public.

  Although early news releases offered general assurances about U.S. reactor safety—“Nuclear power plants are built to withstand environmental hazards, including earthquakes and tsunamis”—the NRC didn’t know enough about the Japanese plants to say with certainty that the safety situation was any better in the United States. For instance, the NRC did not know at the time whether Japan had installed hardened vents at its Mark I boiling water reactors back when most U.S. plants did so, at the urging of the NRC, in 1989.4 And even if NRC officials could legitimately claim U.S. plants were safer, they had to tread carefully or risk embarrassing a major U.S. ally. One NRC staffer called this a “slippery slope.”

  While the NRC was trying to pry more information from Japan, it also faced pressure to be more forthcoming. Some of the push was coming from its own staff. As Jaczko was heading home after the White House meeting, Virgilio asked his boss if the NRC might step ahead of the other federal agencies, “sanitize our Qs and As [about the accident] and post them on the website.” Jaczko said no. “At this point, all of the public communication needs to be coordinated,” he said. “[L]et’s continue to keep it within the federal family.”

  At that moment, the federal family was engaging in a little sibling rivalry, with the NRC butting heads with the Department of Energy (DOE), which fields its own team of nuclear experts, many of whom work in the national laboratories around the country. Those experts were “chomping at the bit” to get involved, which didn’t sit well at the NRC. “[S]omebody might want to call DOE and tell them to tell their labs to cool it,” said the NRC’s Brian Sheron on March 12, “because the last thing we want is the labs going off, talking to the press, talking about consequences and all sorts of other stuff.”

  State officials were beginning to press NRC officials for an assessment of radiation risks to their residents.5 “I think we need to do more with the states,” Virgilio told Jaczko. That’s where most requests for information were coming from, he said. So far, anyway. The U.S. news media, already plying the NRC for information about events in Japan, were also looking for a local angle.

  Eventually, Jaczko and his team knew, the NRC would have to answer the question: could Fukushima Daiichi happen here? For the NRC, that was the ultimate “slippery slope.”

  “I think . . . it’s inevitable that we’re going to get those questions and calls for comparisons of U.S. facilities to [those in] Japan,” the NRC’s Brian McDermott, joining Virgilio on the call, told Jaczko. Jaczko agreed and told his crew to start working on some talking points.

  Later that day, the conversation in the NRC’s Operations Center turned to crafting acceptable answers, first for the states and then, ultimately, for the media and the public. Staying on top of the message could be difficult, the NRC team agreed.

  “[I]f we’re trying to restrict the information, or at least control the information, that we’re getting outside, anything that you give a state or a governor, you’re not going to be able to control what they do with it, even if you ask them to keep it close,” said Dr. Charles L. Miller, an NRC vete
ran who oversaw state programs. Officials in western states, in particular, wanted to know what the NRC knew, especially the likelihood of a meltdown in Unit 1 and the possibility of radiation reaching the United States. So far the NRC had refused to make any public statements about exactly what was happening at Fukushima.

  Together, a handful of staff members drafted the talking points. The gist of the message, they agreed, should be this: The NRC will not speculate. Don’t believe everything reported in the media “by the so-called experts.” Be cautious. “And avoid answering questions on whether it could happen here,” Miller warned. “I mean, I don’t think we’re ready to do that yet.”

  As the crisis continued, the NRC exerted considerable discipline, refraining from appearing to second-guess the plant operators or to make pessimistic assessments ahead of the Japanese. The press releases it issued, while seeking to reassure Americans, flatly stated that “the NRC will not comment on hour-to-hour developments at the Japanese reactors.” As for speculating, Bill Borchardt, the NRC’s director of operations, had his own advice for his impatient colleagues: “Don’t . . . scratch the itch.”

  Within minutes of getting the official go-ahead from Tokyo to “resume” injecting seawater into Unit 1, Yoshida found the next problem landing in his lap. At 8:36 p.m. on March 12, the gauge monitoring water levels in Unit 3 ran out of battery power. In fact, problems in Unit 3 had been quietly multiplying. They, too, involved cooling the core.

  Aware early on that battery life was an issue, the Unit 3 shift team had cut off all nonessential power loads, fearful that if the RCIC stopped for some reason there might not be adequate power to restart it. With battery power alone, operators were able to keep the cooling system running by continuously monitoring the water level and controlling the flow rate.

  Because Unit 3 appeared to be stable with the RCIC limping along, Yoshida and his workers had focused on restoring power to Units 1 and 2. But at 11:36 a.m. on March 12, the RCIC in Unit 3 stopped and could not be restarted. Now Unit 3 needed water and needed it quickly. All available fire engines were being used to pump water into Unit 1. Obtaining another off-site truck was not immediately possible because roads were treacherous.

  Fortunately, Unit 3 had an emergency cooling system that was still functional: the “high-pressure coolant injection” system or HPCI (pronounced hip-sea). When water levels dropped in the core, the HPCI automatically kicked in about an hour later, also drawing on battery power. Under normal circumstances, the RCIC was used to deliver makeup water to replace coolant boiled away by decay heat. The HPCI system, with about ten times the flow rate, is designed for much larger water losses, such as could occur from a ruptured pipe or stuck-open relief valve. But these weren’t normal circumstances, and the operators worked to control HPCI flow as they had been doing with the now dormant RCIC.

  The water level rose and pressure inside the reactor decreased. Yoshida ordered preparations to vent the containment, knowing it was only a matter of time before that became a necessity. He hoped to vent while radiation levels in the reactor building were low.

  The last reading of the Unit 3 water gauge, before the batteries died, indicated that the fuel might be covered by a mere sixteen inches of water. Supervisors doled out thirteen two-volt batteries from the stockpile of fifty batteries that had been delivered overnight from another power station, and the gauge was reactivated. Stabilizing Unit 3 became the priority now that Unit 1 was being cooled by seawater injection.

  However, the HPCI pressure started to drop and the shift team at Unit 3 began to worry that it could not depend on the HPCI much longer. The team decided to switch to external injection, using a diesel-driven fire pump, which team members thought would be more reliable. But to do this, they would first have to depressurize the reactor vessel by remotely opening a safety relief valve (SRV). (The reactor vessel’s pressure had to stay low enough for the low-pressure fire pump to be able to inject water.) The shift team thought opening the SRV was possible because the valve’s indicator light was on in the control room, signaling that the SRV could still be operated from the control panel. Yoshida was notified, but he didn’t think dealing with the issue was a priority in light of other, more pressing crises.

  Shortly before 3:00 a.m. on March 13, the Unit 3 operators decided to shut down the HPCI. However, when they tried to open the SRV, the switch didn’t seem to work and the SRV indicator didn’t change from green to red to show it was open. The workers attempted to use the fire pump anyway and persuaded themselves from a sound they interpreted as flowing water that it was working. None of this was reported to Yoshida until nearly 4:00 a.m. If he had known in advance of the plan, Yoshida probably would not have approved it: he knew the fire pump would not have worked well even if the SRV had been successfully opened.

  After Yoshida discovered what had happened, he decided that the team should try to depressurize the reactor vessel manually, using scavenged car batteries to power the valve controls, and then inject water using a higher-pressure fire engine that had become available from elsewhere on the plant site when a road was cleared. But the reactor had already been without cooling for an hour, and it had entered a critical phase. After a final attempt to restart the HPCI and RCIC failed around 6:00 a.m., Yoshida had no choice but to report to Tokyo that operators had lost the ability to provide emergency cooling to Unit 3.

  Although there is some uncertainty about the timing, by approximately 9:00 a.m. on the morning of March 13, the fuel rods became uncovered, triggering the same sequence of events that had occurred at Unit 1 some thirty-six hours earlier: overheating of the fuel, oxidation of the fuel cladding, hydrogen formation, and release of fission products. The Unit 3 core was melting down, and the vessel pressure was rising fast. As though in a nuclear version of Groundhog Day, workers once again faced the urgent need to vent the containment to reduce pressure so they could inject makeup water to try to halt damage to the reactor core.

  Racing against time, the operators attempted to open the valves in the piping between the containment and an exhaust stack in order to discharge gas, but they couldn’t outpace the increase in pressure within the intensely hot reactor. Another reactor now appeared doomed.

  Three hours passed before venting got under way and the containment pressure dropped. Because core damage had already begun, high levels of radioactive materials were vented and radiation levels at the plant boundary spiked. But soon afterward, a safety relief valve opened, perhaps automatically, and depressurized the reactor, allowing injection of a newly uncovered supply of freshwater in fire cisterns to the core. Freshwater supplies were running low, however, and Yoshida ordered workers to prepare to switch to seawater. Just after noon, the freshwater reservoir had been depleted and workers scrambled to hook up the seawater line. Seawater began flowing in an hour. But once again it was too little, too late; measurements indicated that the core remained exposed, a sign that not enough water was getting into the reactor vessel to re-cover the fuel. Radiation levels were continuing to rise, hitting 1.2 rem (twelve millisieverts) per hour on the Unit 3 side of the shared control room.

  Across Japan, concern was growing about this disaster that seemed to worsen by the hour. Late Sunday evening, TEPCO officials held a news conference. President Shimizu, dressed in a blue company uniform, apologized to the Japanese people and said that the tsunami had “exceeded our expectations.” With that, he dropped out of public view for about two weeks, prompting much speculation in the Japanese and foreign media. (TEPCO officials later explained that Shimizu had fallen ill because of overwork.) Shimizu apparently remained involved in decision making, however. He and Prime Minister Kan would soon tangle over a highly publicized misunderstanding.

  TEPCO corporate management likely wasn’t winning fans inside the frenzied command center at Fukushima Daiichi, either. Tapes of conversations between Tokyo and the center reveal a certain disconnect.

  Earlier Sunday, headquarters had ordered one thousand spare car batteries, but
delivery to the plant was held up for hours by delays in obtaining the government permits necessary to use the expressways. By Sunday night, with the shipment still en route and batteries in employees’ cars and trucks already appropriated, the need for the additional batteries had grown critical. About 7:15 p.m., an announcement blared over the public address system at Fukushima Daiichi: “We are going out to buy some batteries, but we are short of cash. If anyone could lend us money, we would really appreciate it.”

  And despite his responsibilities managing the deepening crisis, Yoshida’s bosses expected him to keep up with the paperwork. The previous night TEPCO headquarters had called the exhausted superintendent asking him to submit his night shift schedules. Yoshida, who at that moment was struggling to get vital water into the Unit 1 reactor, responded: “I’m a bit too beat to prepare them now.” Headquarters persisted and Yoshida eventually replied, “[N]one of our workers can go home anyway. It’s just a question of whether they are awake or asleep.” Whether that satisfied the timekeepers at headquarters is unknown; by the time Yoshida responded to them, they had all gone home for the night.

  Back in the United States, it was early Sunday morning when the NRC’s emergency operations center received a call from Admiral Kirkland Donald, director of naval reactors at the National Nuclear Security Administration, a semiautonomous division of the DOE. Donald wanted to notify the NRC and the DOE, which joined the call, that the U.S.S. Ronald Reagan, a nuclear-powered aircraft carrier off the coast of Japan, had “picked up some activity out at sea that we think you need to be aware of and probably need to be addressing with the Japanese government.” The “activity” was radiation.