Coping with the vast amounts of ground water flowing into the broken Fukushima nuclear plant — which then becomes radiated and seeps back out — has become such a problem that Japan is building a 35 billion yen ($312 million) "ice wall" into the earth around it.

But even if the frozen barrier built with taxpayers' money works as envisioned, it won't completely block all water from reaching the damaged reactors because of gaps in the wall and rainfall, creating as much as 50 tons of contaminated water each day, said Yuichi Okamura, a chief architect of the massive project.

"It's not zero," Okamura said of the amount of water reaching the reactors in an interview with The Associated Press earlier this week. He is a general manager at Tokyo Electric Power Co., or TEPCO, which operates the facility that melted down after it was hit by a tsunami in 2011, prompting 150,000 people to evacuate.

Workers have rigged pipes that constantly spray water into the reactors to keep the nuclear debris inside from overheating, but coping with what to do with the resulting radiated water has been a major headache. So far, the company has stored the water in nearly 1,000 huge tanks around the plant, with more being built each week.

TEPCO resorted to devising the 1.5-kilometer (1-mile)-long ice wall around the facility after it became clear it had to do something drastic to stem the flow of groundwater into the facility's basement and keep contaminated water from flowing back out.

"It's a vicious cycle, like a cat-and-mouse game," Okamura said of the water-related issues. "We have come up against many unexpected problems."

The water woes are just part of the many obstacles involved in controlling and dismantling the Fukushima Dai-chi plant, a huge task that will take 40 years. No one has even seen the nuclear debris. Robots are being created to capture images of the debris. The radiation is so high no human being can do that job.

The ice wall, built by construction company Kajima Corp., is being turned on in sections for tests, and the entire freezing process will take eight months since it was first switched on in late March. The entire wall requires as much electricity as would power 13,000 Japanese households.

Edward Yarmak, president of Arctic Foundations, based in Anchorage, Alaska, which designs and installs ground freezing systems and made an ice wall for the Oak Ridge reactor site, says the solution should work at Fukushima.

"The refrigeration system has just been turned on, and it takes time to form the wall. First, the soil freezes concentrically around the pipes and when the frozen cylinders are large enough, they coalesce and form a continuous wall. After time, the wall increases in thickness," he said in an email.

But critics say the problem of the groundwater reaching the reactors was a no-brainer that should have been projected.

Building a concrete wall into the hill near the plant right after the disaster would have minimized the contaminated water problem considerably, says Shigeaki Tsunoyama, honorary professor and former president of University of Aizu in Fukushima.

Even at the reduced amount of 50 tons a day, the contaminated water produced at Fukushima will equal what came out of Three Mile Island's total in just eight months because of the prevalence of groundwater in Fukushima, he said.

Although TEPCO has set 2020 as the goal for ending the water problems, Tsunoyama believes that's too optimistic.

"The groundwater coming up from below can never become zero," he said in a telephone interview. "There is no perfect answer."

Okamura acknowledged the option to build a barrier in the higher elevation near the plant was considered in the early days after the disaster. But he defended his company's actions.

The priority was on preventing contaminated water from escaping into the Pacific Ocean, he said. Various walls were built along the coastline, and radiation monitors show leaks have tapered off over the last five years.

Opponents of nuclear power say the ice wall is a waste of taxpayers' money and that it may not work.

"From the perspective of regular people, we have serious questions about this piece of research that's awarded a construction giant," says Kanna Mitsuta, director of ecology group Friends of the Earth Japan. "Our reaction is: Why an ice wall?"

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