It was shortly after midnight March 19 at White Flint, and Casto had just left a meeting with Ambassador Roos. Roos knew he might soon face a crucial decision: if the situation at Fukushima Daiichi began to deteriorate, should he be ready to order a much wider evacuation of U.S. citizens and close the embassy? Like the White House, he was demanding better data on a worst-case scenario—information that would allow him to decide if it was safe to stay no matter how bad things got. The DOE had given Roos the results of an accident scenario that Casto had not reviewed. The NARAC models, using a source term known as the super core, were indicating that doses at the embassy could exceed one rem over four days, which would require evacuation under the EPA’s guidelines. When Roos asked Casto about the numbers, Casto later told Virgilio, he felt “blindsided.” Even the American experts advising the ambassador weren’t coordinating their efforts.
In response to the previous White House request, the NRC—despite its reservations—was already developing what it considered a worst-case scenario involving Units 1 through 4. (It was also analyzing a more “realistic” scenario to have on reserve.) But now the ambassador apparently wanted projections for an even more extreme scenario in which Fukushima Daiichi Units 5 and 6 also melted down. For Virgilio, this demand went too far, given that Units 5 and 6 were relatively stable. He also presumed that the results would indicate the need to evacuate Tokyo. “[T]hat’s why we’re trying to do a worst-case that really makes sense given the conditions that we have now,” he said. “I mean the team spent half the night last night trying to figure out where do we start from.”
“Well, and I appreciate that work,” Casto said. “I expect he’ll turn to DOE and say, give me the worst case.”
“You know the old adage,” warned Virgilio, “ ‘Be careful what you ask for.’ ”
“I think they’re trying to get something out to [embassy] employees to show that it’s safe . . . no matter what happens—even if the extreme happens—it’s safe to be in Tokyo,” Casto said.
Finding the right answer—or at least a best guess—for the ambassador became even more urgent. The prevailing winds were about to start blowing toward Tokyo and continue in that direction for twelve hours.
But this was not an easy task. The debate among the NRC, the DOE, and the White House Office of Science and Technology Policy over whether to evaluate worst-case scenarios and in fact, what exactly was the worst-case scenario continued to percolate over the next several days, and was a source of considerable friction among the agencies. Although the NRC’s emergency planning strategy included the ability to estimate source terms based on stylized cases, the urgent need for the NRC to produce something that accurately modeled a real-world event put the agency in a bind. Nobody ever figured they’d have to do it in real time for an accident as complicated as Fukushima.
At one point on March 20, the NRC’s Jim Wiggins said, in apparent frustration, “I still won’t let anyone use the word ‘worst case’ in the room here . . . because there’s about five worst cases.”
The White House and the DOE were griping about the NRC’s performance as well. For instance, they found mistakes in the source terms that the NRC had been using. When the NRC modeled the Unit 4 spent fuel pool, it assumed that a fairly large amount of iodine-131 had been released. But the fuel most recently discharged into that pool had aged over three months. In that time, most of the iodine-131 should have decayed away. It turned out that the NRC had received erroneous information leading the staff to believe that the most recent batch of fuel had been discharged from the reactor only a month before the accident; thus, the NRC’s model greatly overestimated the iodine release and resulting radiation doses to the thyroid that would be associated with a Unit 4 fire. But before this mistake was discovered, NARAC had used the source term to calculate trans-Pacific doses, finding some alarmingly high results—four rem (forty millisievert) thyroid doses to one-year-old children in California over a two-month period, for example—although these were still below the thresholds for protective action.
Interagency rivalries only compounded the difficulties. Early on, the NRC team at White Flint complained about interference from the DOE’s experts at the national laboratories. The DOE later fired back with its own critique. A postaccident evaluation, prepared by two experts from Sandia National Laboratories, criticized the NRC, saying the agency “did not seem to engage aggressively until four or five days into the event.” In addition, NRC emergency planning personnel were “very reluctant” to engage with their own colleagues on the research staff who had previously done analyses of events very similar to those unfolding at Fukushima, according to the Sandia study. Other Sandia experts also reportedly dismissed RASCAL as a “toy model” that should not have been used to study real-world events.
At 8:00 p.m. on March 19, Brian Sheron led a conference call updating other NRC staff members on the day’s events. The afternoon meeting with the industry consortium had gone well, he reported, running beyond the ninety minutes originally planned. Industry people seemed receptive to working closely with TEPCO, offering suggestions or support. The DOE would use its NARAC resources to project dose rates in Tokyo based on the predicted wind change toward the city, but at this point there appeared no reason to alter the fifty-mile evacuation zone for Americans in Japan.
Less than an hour later, Chuck Casto was calling. “Here’s today’s crisis,” he said to Virgilio and Sheron. After resisting requests for information and offers of help for days, now TEPCO was accusing the United States of dragging its feet.
Ambassador Roos, his staff, and Casto had just returned from a meeting with the utility. The TEPCO officials wanted to hear the NRC’s assessment on radiation levels and the salt accumulation in the reactors—something TEPCO had asked for just a day earlier. “Well, honestly, I didn’t have a wallet in my back pocket on that,” Casto told his colleagues. “I said, ‘Well, you asked me about it yesterday. There’s a lot of information, a lot of analysis, and I believe we’re working on that.’ ” TEPCO was insistent. “They basically said, we need this stuff immediately.”
Now it was time for the NRC to step back a little, Casto told Virgilio. The Defense Department was willing to bring in whatever heavy equipment was needed. “[W]e’re not working the logistics stuff,” said Casto. “It’s out of our lane.” And the new industry consortium could work more closely with TEPCO.
As a trade-off for the NRC’s ongoing technical assistance, the Japanese should be expected to hand over data, Casto said. “[W]e don’t know the condition of the reactors . . . , what containment pressure is, what reactor pressure is, whether those things are even full. Nevertheless, all that’s moot. The bottom line is get water. They need to get freshwater into that reactor.”2
One way to start getting freshwater for the reactors would be to get desalination equipment up and running, but this would have to wait until power was restored to the site. The team back at White Flint promised to review research papers on the salt issue and get back to Casto and Monninger, who was also on the line from Tokyo.
“I’m glad you brought that up because let me make it clear,” Monninger said. “We really need you guys to be the brain waves and give recommendations. [H]ere we can’t really read stuff and come up with thoughts and recommendations and that kind of stuff. We want to be the, you know, the grease.” The Tokyo group was too preoccupied by the never-ending stream of crises, and perhaps just too beat, to spend precious time scrutinizing scientific research. Earlier, Monninger had told his colleagues he yearned for “100 hours of sleep.”
At 10:00 a.m. Sunday, March 20, industry representatives joined in a conference call with the NRC operations team at White Flint to brainstorm. The industry consortium, working out of the Marriott across the street from NRC headquarters, had agreed to send two of its technical people to Tokyo that evening or the next day to work with Chuck Casto, and then to embed them at TEPCO’s emergency operations center. That, everyone hoped, might improve communications.
Almost from the outset of the accident, the Japanese nuclear industry had reached out to the U.S. nuclear industry for help, leaving the NRC as a bystander. On March 12, field representatives in Japan for GE-Hitachi, a U.S.-Japanese nuclear partnership, had contacted Exelon, the Chicago-based utility, and asked Exelon to run accident simulations for the reactors in its fleet that were of the same design and vintage as those at Fukushima Daiichi. (However, this information did not prove very useful—Exelon’s attempt to model what was going on at Unit 1 on the simulator at its Quad Cities plant predicted a primary containment pressure that was only 3 percent of what was being reported.)
And the Nuclear Energy Institute appeared to have access to valuable information the NRC didn’t have. The NEI had dose rates the commission had been seeking, for example. (The NRC’s information often came from unexpected places. Details about radiation levels in spinach came from the Wall Street Journal. “It’s amazing how people know this stuff and we can’t seem to get it,” marveled a member of the White Flint crew.) Maybe things would improve with industry bridging the gap.
The status of the Unit 4 spent fuel pool still worried the NRC team. Although on March 20 the Japanese had finally begun using fire engines and then pumper trucks to spray tons of water toward the Unit 4 pool, as they had been doing at Unit 3 for several days, workers were shooting the water from such a distance that “you have incredible losses,” Monninger told his colleagues. (The arrival of the kirin trucks was still two days away.) “[T]he media [are reporting] that these fire trucks are going in and out, the helicopters are doing this, the super capacity pumping system. But then, when you actually [get] down into TEPCO and start talking to the engineers, you find out that it really isn’t that effective.” If it had been, radiation levels would have dropped, but, when pushed on the subject, the Japanese reported no change.
The NRC remained convinced the pool was dry—a view at odds with the Japanese belief. “We’ve got to be very careful with that because we got in trouble before by passing up that information,” warned Monninger.
If the pool were in fact dry, the threat it posed was enormous. The intensely hot fuel could now be melting into the concrete pool floor. And sitting below that was the torus, filled with more than a million gallons of water. If the molten fuel reached the torus, it could vaporize that water almost instantly, causing a powerful steam explosion that could propel radioactive core material far and wide. (However, as with the NRC’s earlier belief that the pool was empty, fears about the molten fuel also proved unfounded. A computer simulation the next day indicated the fuel would not be hot enough to melt through the pool floor.)
On another topic, Monninger related that after days of seeking an invitation, he and Jim Trapp had finally made it to the TEPCO emergency operations center. Its scale surprised them. “This place was massive,” he said. “There’s probably 250, 300 people in that room.” In addition to the sheer size of the TEPCO operation, the visit to the utility’s operations center was notable for another thing, Monninger told his colleagues: “There’s huge [numbers of] protesters, cameras, cops surrounding the TEPCO facility.” Official visitors were now whisked in via an underground garage.
Assuming the spent fuel in the Unit 4 pool was still covered with water, it would require seventy-two tons more water every day to cover losses from evaporation. The Japanese were aiming at least that much at it. The Unit 2 pool was targeted for twenty tons a day; Unit 3, ten tons a day; and Unit 1, five tons a day. But no one knew how much of this water was reaching the pools and how much was missing them and flowing elsewhere in the reactor buildings.
“One of the concerns is they turn the site into a swamp,” said Monninger, “but the other is just the contamination and the runoff from all this water that’s not going into the spent fuel pool.”
WATER REFLECTIONS
Water propelled by tsunamis flooded the Fukushima Daiichi site, disabling the power supplies for nearly all of its safety equipment.
Lack of water damaged the Units 1, 2, and 3 reactor cores and threatened to damage fuel in the Units 1, 2, 3, and 4 spent fuel pools—if that had not already happened.
Lacking freshwater sources, workers tried to address those problems by injecting seawater into the reactor cores. But seawater corroded reactor parts more rapidly and left salt behind that might eventually block the cooling water flow.
Water dumped from helicopters and sprayed from fire trucks was intended to refill the pools and protect their spent fuel from damage.
But water that missed the spent fuel pools could end up draining down into the reactor buildings below and flooding their basements. Workers struggling to repower the Fukushima site might find their efforts thwarted if flooding submerged the safety components on the other ends of the re-run power lines.
Ironically, water took away most of the options available to responders and left them none without potentially catastrophic consequences.
The lack of information on the status of the spent fuel pools was just one of many factors causing angst and blocking interagency consensus on a plausible source term. While the NRC had thought that it finally gave the DOE and NARAC the worst-case source term they were seeking, NARAC was continuing to ask the NRC for more information. At 8:30 the next morning, the White House was convening a meeting to bring together the warring parties. The goal of that meeting was to reach a public policy decision based on science, but in the case of source terms, the science was anything but solid. There were just too many variables, to say nothing of biases.
Getting the source term right was far more than an academic exercise. The safety of American civilians and military personnel in Japan and potentially millions more in Pacific island territories, Alaska, Hawaii, and even the continental United States was involved. Was the threat real enough to distribute potassium iodide tablets to reduce the effects of radiation exposure to the thyroid? Underestimating the hazards could leave many people in harm’s way. Overestimating them could result in the unnecessary movement of large numbers of people—which itself could result in casualties.
Now, it came down to whether NARAC should use a “realistic” worst case or a “worst” worst case. But who could say, given all the extreme events that had already occurred, what was truly “realistic” at this point?
To break the impasse, Jaczko’s office wanted the NRC to send to the meeting not only a technical expert but also someone with senior-level credentials and experience to go “nose to nose” with Dr. Steven Aoki, deputy undersecretary at the DOE, home to NARAC, to press the NRC’s position. Charlie Miller, a veteran department chief, was recruited for the task. A successful outcome, according to Virgilio, would be an “agreement high enough up that my folks wouldn’t continue to bang their heads against the telephone back and forth with folks at our level about what assumptions are, and they would actually do some calculations for us.”
This was likely easier said than done, however. As Mike Weber, the NRC’s deputy executive director, told Miller, “probably what you’re going to find out as each party weighs in is everybody has a different definition of worst case as their own . . . so we’ve got to come to the common agreement to go forward.”
And impatience with the lack of a definitive answer was growing among a host of federal agencies—all with a stake in the decision. As Marty Virgilio put it, “DOD wants to know where to move their ships. EPA and others want to know what to expect on the West Coast. HHS [Health and Human Services] wants to know what kind of levels in order to make recommendations on whether or not they should actually recommend potassium iodide [tablets] at some point. And it goes sort of on and on.”
Much of the give-and-take at that Monday morning meeting at the White House remains secret. But at the heart of the discussions was finding a way to make the best judgment call on radiation risks in the face of such uncertainty. Were conditions dire enough to warrant an evacuation order for U.S. personnel in Tokyo? Some of the data in White House hands indicated it
might be necessary. At the other extreme, should the fifty-mile evacuation advisory be lifted, as some were urging? (Ultimately, the fifty-mile evacuation zone remained in place until October 2011, when the State Department reduced it to twelve miles.)
Even as Miller headed to the White House, the White Flint team was receiving important new information that could dramatically alter source term assumptions. The Unit 4 spent fuel pool, although heavily damaged, apparently had water, reducing the risk there somewhat. “Do we have any idea how we got it in there?” someone asked. The answer was no; nor did anyone know how much water the pool contained.
The NRC elected not to try to change the source term numbers at this point. “It took two days to negotiate this source term,” said a member of the NRC crew. “I don’t know if we want to spend another two days trying to negotiate another one.”
Finally, an agreement was reached among the White House science advisors, the DOE, and the NRC on a scenario the NRC pointedly referred to as “the President’s source term.” This case assumed releases from three reactors and four spent fuel pools, but used “best estimate” simulations for the amount of radioactive material released from each source based on computer models of the accident using the NRC’s own computer code, known as MELCOR—introducing what the agency believed was “realism” into the analysis.3
NARAC’s results for the “President’s source term” turned up one disturbing finding: a potential thyroid radiation dose to a one-year-old child on the West Coast of the United States of 4.5 rem, not far below the 5-rem EPA threshold for protective actions such as potassium iodide administration or interdiction of milk supplies. So the fears of some Americans that Fukushima could impact them were perhaps not as far-fetched as the U.S. government had led them to believe. However, because this result was below the threshold, it did the trick: even in the worst case, nothing needed to be done to protect the children in California.
Fukushima: The Story of a Nuclear Disaster Page 18