KELLY MCEVERS, HOST:
Tomorrow marks five years since Japan was hit by a powerful earthquake and tsunami. The wall of water struck many points along the coast, including the Fukushima Dai-ichi nuclear power plant where three nuclear reactors melted down. NPR's Geoff Brumfiel reports that some progress has been made in cleaning up the site since then, but there's still a lot of work left.
GEOFF BRUMFIEL, BYLINE: When the crisis began at Fukushima Dai-ichi, hundreds of thousands of people fled. Radioactivity spread across rice paddies and towns. Five years later, the cleanup is well underway, and some villages are again open to residents. But there's still lots and lots of problems, and Dale Klein, a former chairman of the U.S. Nuclear Regulatory Commission, says one really stands out.
DALE KLEIN: I think what makes Fukushima Dai-ichi the most challenging is water.
BRUMFIEL: Klein now consults for the Tokyo Electric Power Company or TEPCO which owns the plant. The water he's talking about comes from the mountains surrounding the reactors. It's groundwater that constantly seeps through the ruined buildings before spilling into the ocean. Efforts to stop it have only been partially successful. TEPCO has gotten good at filtering radioactivity out of this water, but one isotope of hydrogen called tritium cannot be removed because it's literally embedded in the H2O of the water molecules.
KLEIN: Tritium is a part of the water itself, and so how do you filter water out of water?
BRUMFIEL: The best solution might be to dilute the radioactive water and then release it into the ocean. But fishermen and the public would have to be convinced. For now, it's being stored on-site.
KLEIN: There are about 1,000 containers - steel containers that hold this water.
BRUMFIEL: The land around the plant was also contaminated by the accident. Azby Brown is with the nonprofit Safecast organization which independently monitors radiation levels in Fukushima prefecture. He spoke via Skype from Tokyo.
AZBY BROWN: There's no question that the radiation levels have decreased compared to 2011.
BRUMFIEL: A recent government survey showed that levels are down by more than half since the accident. Some of that drop is due to the natural radioactive decay, but there's also been a huge cleanup effort. Workers across Fukushima have been scraping up contaminated topsoil and storing it in bags. And that's created its own problem, Brown says.
BROWN: There are now about 9 million bags of decontamination waste from all over the prefecture that are being consolidated into these vast fields with these sort of pyramids of, you know, radioactive waste.
BRUMFIEL: Just like the water, regulators aren't quite sure what to do with all that soil. But the biggest issue long-term is how to deal with the highly radioactive cores of the reactors themselves, each filled with melted uranium fuel. Takafumi Anegawa, TEPCO's chief nuclear officer, says it's got to be removed.
TAKAFUMI ANEGAWA: This condition cannot continue for many years.
BRUMFIEL: But Anegawa also says TEPCO doesn't really have a clue how to get the melted fuel out.
ANEGAWA: So far, there's no specific, clear solution.
BRUMFIEL: In fact, the company hasn't even been able to look inside to see what needs to be done. The radiation is so intense, Anegawa says, it's fried the circuits of several robots sent in to investigate. Dale Klein, the safety consultant, thinks that eventually, robots will be used to cut up the molten cores of the reactors and seal them inside concrete containers. But he says it's not going to happen overnight
KLEIN: This will be a several-decades process of cleanup. It will be much more complicated than a 3-mile island. In a 3-mile island, it took 14 years to clean up.
BRUMFIEL: In other words, the Fukushima accident will be with the people of Japan for generations to come. Geoff Brumfiel, NPR News.
NPR transcripts are created on a rush deadline by Verb8tm, Inc., an NPR contractor, and produced using a proprietary transcription process developed with NPR. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.