Update 3/16/11 3:03 PM: The news doesn’t get better. At an afternoon Congressional hearing, Nuclear Regulatory Commission chairman Gregory Jaczko said that the all the water in the spent fuel pod in the number 4 reactor at Fukushima Daiichi has almost certainly boiled away:
We believe that radiation levels are extremely high, which could possibly impact the ability to take corrective measures.
Because the water in the pools not only cool the fuel rods but also block radiation, workers likely couldn’t even approach a fully exposed rod. It’s not clear now how TEPCO will be able to cool down number 4 reactors spent fuel rods.
Jaczko also said that the American Embassy, on the advice of the NRC, was recommending that Americans in Japan be evacuated approximately 50 miles from Fukushima. That’s much further than the recommendations set by the Japanese government, which calls for citizens to move at least 12 miles away from the plants.
A nuclear power plant creates energy through a chain reaction, one that harnesses the power of fission without losing control. It’s becoming increasingly clear that what we’re seeing at the disaster-stricken Fukushima Daichi nuclear power plant is a reaction of a very different and frightening kind, as one failure leads to another and another, overwhelming attempts to slow down the accident. The question now is how much longer the last-ditch safety measures at the damaged units can hold out before the chain reaction that began with a 9.0 earthquake on March 11 and subsequent tsunami gets irretrieviably out of control.
We may be close—according to the International Atomic Energy Agency (IAEA) Yukiya Amano, the unfolding catastrophe in Fukushima is “very serious.” The IAEA reported that damage to the cores of three units had been confirmed. (The situation was dire enough that Amano was planning a trip to Japan—which may help address the communication problems betwen Japanese officials on the ground and the UN nuclear watchdog.) That appeared to contradict claims made earlier on Wednesday by Japanese Chief Cabinet Secretary Yukio Edano that the damage to the number 3 reactor at Fukushima was not very severe, but the fast-moving, fast-changing circumstances surrounding the crippled nuclear plants made confirming the truth difficult—if indeed anyone knows for sure at this point. But there’s little evidence that things on the ground are improving. “It’s unclear if the extent of the damage that has occurred can be contained,” says Edwin Lyman, a senior scientist at the Union of Concerned Scientists’ Global Security program.
The radioactive risks—at least temporarily—were high enough at the plant that the Japanese military put off a planned mission to drop water on a pool containing overheating spent fuel rods at reactor number 4, and instead were forced to employ water cannons of the sort normally used by riot police. (Ecocentric’s Eben Harrell explained yesterday why the spent fuel rods could present an even greater radioactive risks than the troubled reactors themselves.) After being forced to temporarily evacuate all but 50 workers from the Fukushima plant yesterday because of a spike in radiation levels—though seawater was still being pumped into the reactors to speed cooling—Tokyo Electric Power (TEPCO) was able to increase the number of workers to 100 as they struggle to keep the atomic fuel cooled and prevent a meltdown or explosive release that could spread radiation well beyond the plant.
But on the ground, the fight was not going well. Fires burned at the number 4 reactor building, then smoke disappeared—but officials couldn’t be sure if the fire had actually gone out. As a sign of just how bad things are getting, the Japanese government raised the amount of radiation workers could be exposed to from 100 millisieverts to 250 millisieverts. “The workers are in a situation from an occupational health and safety perspective is really serious and daunting,” says Dr. David Richardson, an epidemiologist at the University of North Carolina and an expert in radiological health.
There is also fuel damage at units 2, 3 and 4 at Fukushima—though again, because the scene is so chaotic and dangerous, officials can’t be sure just extensive the damage is. That information gap has left even experts unsure of the degree of the danger. At a meeting of the House Energy and Commerce Committee, Energy Secretary Steven Chu said that the disaster seemed to be worsening:
We think there is a partial meltdown…
We are trying to monitor it very closely. We hear conflicting reports about exactly what is happening in the several reactors now at risk. I would not want to speculate about what is happening. Let’s just say we monitor it very closely and we will take it as it comes.
Other international officials expressed greater worry than Chu, at least publicly. Gunther Oettinger, the European Union’s energy commissioner, warned that the situation was spiraling “out of control,” while Switzerland advised citizens living in northeast Japan or Tokyo to leave the area and began laying in plans for charter flights out of the country. The Japanese broadcaster NHK reported that radiation levels 0.08 mSv per hour 15 miles away from the plant—outside the exclusion zone around the facility—a level dangerous enough to cause health problems if people remain in the open for a long period of time. The U.S. military announced that it would not allow personnel within 50 miles of the plant. “This is an incredibly difficult situation with a lot of uncertainty,” says Dr. Ira Helfand, the past president of the Physicians for Social Responsibility, a group that opposes nuclear power on human health grounds.
To Nature writer Geoff Brumfiel, this is all enough to suggest that the accidents at Fukushima may not be containable:
Instrumentation has been lost and the extent of the meltdown is unknown, as is the precise condition of the heavy pressure vessels that surround the reactors. The status of a good portion of the plant’s used nuclear fuel — kept on site in storage pools — is also unknown. Realistically, there is little that TEPCO or the government can do except to pump water and hope for the best.
I fear he may be right. Aside from the brave workers at Fukushima who are still struggling to stop the accident from worsening, hoping may be all that’s left for most of us.