But engineers planning that unprecedented cleanup job face questions about where they will put the water and how effectively they can filter its radioactive particles.
Tepco’s problem “resembles a board game with 16 squares and one empty spot,” said David Lochbaum, a nuclear engineer with the Union of Concerned Scientists.
Workers must inject the reactor cores with water to keep them cool. But that step guarantees that water will leak through the quake-damaged plant and into the basement-level turbine rooms. The resulting radioactive water makes repair work all the harder. That means workers, still struggling to fix the usual recirculation system, must continue to “feed and bleed” the reactors from above.
And that means water levels continue to rise down below.
“They’re just perpetuating the problem and making a bigger and bigger mess,” said Lake Barrett, a nuclear engineer who directed the cleanup of the hobbled Three Mile Island plant in Pennsylvania.
A potential turning point may come in about two weeks, when Tepco plans to begin a treatment process in which water will be sucked from the basement rooms and fed into a tank, then treated with chemicals that eliminate radioactivity. The process will create a byproduct of radioactive sludge, which is generally mixed with bitumen, poured into drums, sealed and buried. The water can be cycled back into reactors or discarded into the ocean.
The treatment system is being set up by Areva, a French company that uses the technology at its La Hague nuclear reprocessing plant off the Normandy coast. Since 1997, Greenpeace — after taking water samples from La Hague’s discharge pipe — has repeatedly asserted that the supposedly decontaminated water contains radioactivity levels above the regulatory limit.
The process “is not 100 percent, but it’s better than nothing,” Lochbaum said. “The alternative: You let the water simply evaporate, and radioactivity carries to all parts far and wide.”
Japan has experienced substantial environmental problems from the failure at Fukushima, with authorities at the plant discharging contaminated water into the Pacific Ocean on at least three occasions. During a visit to Japan last week, Greenpeace officials presented data showing higher-than-legal radiation levels in seaweed and shellfish that were collected more than 12 miles from the plant. The samples’ high concentrations of iodine-131 — which has a half-life of eight days — indicated that leaks from Fukushima Daiichi were ongoing and “much larger than has been declared by Tepco so far,” said Jan Vande Putte, a Greenpeace radiation expert.