Japan Studies Plan to Contain Radioactive Water

Japan to stem spread of radioactive water at Fukushima with subterranean ring of ice.

By PHRED DVORAK

The leakage water from the Fukushima Daiichi Nuclear Power Plant has been declared a level 3 "serious incident" by regulators. The WSJ's Deborah Kan speaks with Kathryn Higley, Head of Nuclear Engineering at Oregon State University.

TOKYO—Japan is considering a novel approach to stem the spread of radioactive water at the crippled Fukushima Daiichi nuclear plant: installing a subterranean ring of ice.
The project, being touted by Japanese officials from the chief government spokesman to the minister overseeing the plant's private operator, is risky because it could cost hundreds of millions of dollars and hasn't been tried on such a large scale and over such a lengthy period before. Indeed, some experts view it as a stopgap measure.

But the government, which said recently it would take the lead from the plant's operator, Tokyo Electric Power Co., 9501.TO -2.55% after Japan's nuclear regulator last week declared a 79,000-gallon leak "a serious incident," is leaning towards the ice plan as the best and fastest chance at keeping groundwater from becoming contaminated.

The government has ordered a study on the proposal to be completed by year's end.
The push to move ahead with the project despite its uncertainty underscores Japan's scramble—29 months after Fukushima Daiichi melted down following an earthquake and tsunami in one of the world's worst nuclear accidents—to prevent potentially dangerous amounts of radioactive contamination from spreading through water beyond the plant.

Signaling growing concern, Fukushima prefecture's fisheries cooperatives on Wednesday said their members have suspended plans to restart fishing in the waters near the plant, until it is clear they aren't contaminated.
Further, during the past few days, some regulatory officials have questioned whether last week's leak at a site outside the proposed ice ring could mean groundwater is already contaminated over a larger area than initially thought.
So far, the amounts of radioactive water that have leaked out to the sea don't pose much risk to human health, experts say.

At Fukushima, the Battle Continues

Reuters

Workers move radiation-contaminated waste at a storage site in Naraha town, which is inside the former no-go zone within a 20-kilometer (12-mile) radius of the crippled nuclear-power plant. Currently, it is a designated evacuation zone.

Still, some of the Japanese experts on a closed government-appointed panel who have met to hammer out a water-containment strategy in recent weeks are considering using the ice wall as a defense against the spread of contaminated water over the three or four decades that experts believe it will take to clean up Fukushima Daiichi.
Others see it as a temporary measure while other more conventional barriers are erected from steel or concrete, say people with knowledge of the panel's discussions.
In another scenario, the plant's reactors and surrounding areas may have to be guarded by layers of defenses including the ice walls, some on the panel say, according to the people with knowledge of discussions.

Fukushima Daiichi: The Battle for Containment

More than two years after suffering one of the world's worst nuclear accidents, the compound remains a challenge for the operator and regulators.

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In any case, the government this month pledged people and money for the ice-wall project, which could cost several tens of billions of yen to build and nearly ¥1 billion ($10 million) a year to maintain, according to an estimate from another government panel.
The project entails circulating super-cool liquid through a line of pipes inserted into the ground every yard or so. The pipes freeze the soil and groundwater around them, which solidifies into a solid wall of ice that blocks all movement of water.
Experts say an ice barrier could be advantageous at Fukushima Daiichi, where Tokyo Electric Power, known as Tepco, is struggling to keep an estimated 1,000 metric tons of groundwater that flows through the site daily towards the sea from getting contaminated by contact with the damaged reactors and other radioactive spots.
An ice wall around the reactors could completely shut groundwater out of the most heavily contaminated areas, and it is faster to build than other traditional sunken barriers, said Atsunao Marui, head of the groundwater research group at Japan's National Institute of Advanced Industrial Science and Technology, and a panel member.
Kajima Corp., 1812.TO -1.37% the giant Japanese contractor that proposed the ice wall, estimated total construction time would be under two years, versus two or more years for other barrier types.
Meantime, Tepco is applying and preparing measures, including pumps, sea walls and removal and storage of 400 tons of contaminated water a day.
But experts also point out drawbacks to the plan. The wall needs a constant supply of electricity to keep frozen—an expensive proposition, especially in Japan, where the closure of most of the nation's nuclear plants following the Fukushima Daiichi accident means power is largely supplied by costly, imported fossil fuels.
"Ground freezing is usually looked at last because of the cost,'' said Joseph Sopko, director of ground freezing at New Jersey-based geotechnical contractor Moretrench America Corp.
More troubling for the experts panel is that ground freezing hasn't been done on such a scale before. Kajima's proposal calls for a nearly mile-long ring of 1,540 pipes, passing near spots where high levels of radiation have been measured.
Companies are also concerned that their small pool of expert engineers could be devastated if they are accidentally exposed to high levels of radiation, said one person close to discussions on the ice-wall experts panel.
A handful of big ice-wall projects have been planned, but never realized, including one at a gold mine in Canada that was abandoned when gold prices fell and the cost become prohibitive, and another at a nuclear cleanup site in Washington state that turned out to be too dry to work well, Mr. Sopko said.
Only a few Japanese companies specialize in ground freezing, largely for tunnel and other underground construction. One has already bowed out, saying the Fukushima Daiichi project is beyond its technical expertise. Another, the subsidiary of Kajima, has largely handled jobs that are a fraction of the size and are maintained for a year or two, according to a list of projects on its web site.
Part of the goal of the feasibility study being conducted now is to see if the ice wall can be built and maintained with a non-specialist engineering staff, the person said.
—Mari Iwata contributed to this article. Write to Phred Dvorak at phred.dvorak@wsj.com

A version of this article appeared August 29, 2013, on page A8 in the U.S. edition of The Wall Street Journal, with the headline: Japan Studies a Novel Plan.