The troubles at the Fukushima Daiichi nuclear plant began over two years ago when an earthquake and tsunami sparked meltdowns in three reactors. But events over the past week serve as reminder that the problems are far from over.
First, a remote camera spotted steam rising from one of the melted down reactors at the plant. The steam was first seen at the unit 3 reactor late last week, and it's continued on-and-off ever since.
Steam rising from the ruins became an iconic image from the early days of the accident, so many were startled by the fresh video. They had reason for concern: The uranium fuel is still inside unit-3, and even two years after the accident it is still warm. Some fuel could have shifted and created an unexpected hot spot, or worse restarted nuclear reactions.
But both scenarios appear unlikely. The Tokyo Electric Power Company (TEPCO), which owns the plant has been monitoring temperatures, pressures and radiation levels, and has seen little change since the steam started rising. Instead, they're pointing the finger at rainwater, which may be turning to steam as it strikes the hot outer shell of the reactor vessel.
Nevertheless, the plant continues to be a hazard to its surrounding environment. On Monday, TEPCO admitted that radioactivity from the plant is leaching into the water table and flowing from there into the Pacific. The admission confirms what many observers had long suspected: that the company has not been able to contain radioactive water that flows out of the melted cores through cracks and broken pipes.
TEPCO is working to halt the groundwater leaks. They have put chemicals in the soil to make it less permeable, and they'll soon asphalt over the ground around the plant to try and prevent rainwater from exacerbating the problem. The long-term solution is to install a 30-foot deep steel wall between the plant and the ocean, but that is expected to take more than a year, according to one TEPCO official who spoke to NPR but asked not to be named because he isn't a designated spokesman.
It's difficult to say just how dangerous the radioactivity from the plant actually is, says Jota Kanda an Oceanographer at the Tokyo University of Marine Science and Technology.
"I think radionuclides from the plant will eventually spread out into the vast Pacific," Kanda says. But he adds that the leakage will contribute to local contamination of the marine environment.
That will have knock-on effects for Fukushima's economy, he adds. Commercial fishing was once a major industry in the area surrounding the plant, but it's been on hold since the accident. Fishermen had hoped to start trial catches soon, but the new revelations about the radiation leak are likely to sideline those plans, Kanda says.
Water will continue to be an issue for some time to come. Four hundred tons of groundwater infiltrate the plant each day, and it must be decontaminated and stored in tanks, which are piling up around the site. Eventually, TEPCO will run out of space, but for now the company isn't saying when that will happen or what it will do when it does.
DAVID GREENE, HOST:
Here's an unsettling image: for the last few days, steam has been rising from one of the reactors at the crippled nuclear power plant in Japan. As you might remember, that facility, the Fukushima Daiichi plant, was all but destroyed by an earthquake and tsunami. Two years later, the company that owns the plant is still struggling to control the damage. And to understand what's happening there, we're joined by NPR's science correspondent Geoff Brumfiel. Geoff, thanks for coming in.
GEOFF BRUMFIEL, BYLINE: Thank you.
GREENE: So, this steam, where is it coming from?
BRUMFIEL: Well, it's coming from the Unit 3 reactor, which is one of the three reactors that melted down at the plant. But nobody knows exactly where in Unit 3 it's coming from, because the reactor is just too radioactive to get near. Now, there's a fear that it could come be coming from inside the reactor vessel itself, where the melted down fuel is, and that some of that fuel is heating up again. Maybe there's a hotspot. There's a small chance that the nuclear reactions could have restarted.
GREENE: Likely that might be happening?
BRUMFIEL: No, no. It's very unlikely. Fortunately, TEPCO, the company that owns the plant, has been monitoring the reactor very closely. And all the indications are that this is not a result of any new nuclear reactions inside the reactor vessel. Their best guess is it's been rainy and humid in Fukushima, and they think that rain is falling onto the outside of the vessel that holds all this nuclear fuel. That outside is still hot. It's still 104 degrees Fahrenheit. And so that could be causing the rain to come up as steam.
GREENE: OK. So, it sounds like the steam may be not that dangerous a situation. But one concern has also been just the groundwater possibly being contaminated around the plant. And the company comes out and says now, for the first time, yes, that's happening.
BRUMFIEL: Right. For a long time now, it's been clear that there's been radiation still coming out of the plant into the Pacific Ocean. This plant is right on the coast, which is how it struck by a tsunami. Until now, TEPCO has claimed that this is a result of some residual radiation from the initial accident. But they drilled some test wells, and they're now admitting that the groundwater around the plant is contaminated with radioactivity. And this is a big admission for the company.
GREENE: OK. And how much of a risk does that pose to the public?
BRUMFIEL: I've been speaking to some experts in Japan. It's a little unclear at this point, because the problem is that we don't know exactly how much there is and we don't know exactly where it's going. It's difficult to say. It's just soaked into the ground. What we do know is that it probably is being dispersed out into the ocean. And while it's creating a local problem around the plant - and there's already a lot of radioactivity out in the seabed there - it's unlikely to pose any sort of a major risk at this stage.
GREENE: And I guess one question is: What is the company going to do about this groundwater problem?
BRUMFIEL: Well, I mean, there's a limited number of things it can do, because, obviously, it can't, you know, there are broken pipes in the plant. The plant itself is damaged, and water is flowing into the plant all the time, partially to keep it cool, partially just brown water flowing into the basement. So they can't really stop the water. What they could do is try and stop it from going in the ocean. So they're putting in some chemicals into the soil to try to harden it, make it less permeable to water. They're going to asphalt over the top of it to try and keep rainwater from getting in. Eventually, they're hoping to put a huge, 30-foot-deep steel wall into the ground that will literally serve as sort of a barrier for that water from getting into the sea. But that's going to take a year.
GREENE: That sounds like an elaborate process. And I guess, in a way, all this is a reminder that two years is not that long when it comes to recovering from a nuclear disaster like this.
BRUMFIEL: That's right. And, I mean, these are issues that TEPCO's going to be wrestling with for decades. And Chernobyl - in many ways, a much more dangerous accident back in the '80s - they're still working out how to deal with the nuclear remnants of that accident, which are still radioactive.
GREENE: Geoff Brumfiel, thanks for coming in.
BRUMFIEL: Thank you very much.
GREENE: He's NPR's science correspondent. Transcript provided by NPR, Copyright NPR.