March 11 (Bloomberg) -- Every morning, 3,000 cleanup workers at the Fukushima disaster site don hooded hazard suits, air-filtered face masks and multiple glove layers. Most of the gear is radioactive waste by day’s end.
Multiply those cast-offs by the 730 days since a tsunami wrecked the Dai-Ichi nuclear station two years ago and the trash could fill six Olympic swimming pools. The tens of thousands of waste bags stored in shielded containers illustrate the dilemma of dealing with a nuclear accident: Everything that touches it becomes toxic.
Contaminated clothing represents just a fraction of the waste facing Tokyo Electric Power Co. in a cleanup that may take four decades. A tour of the plant last week went past rows of grey and blue tanks holding enough irradiated water to fill 100 Olympic pools on the plateau overlooking Dai-Ichi’s four ruined reactors. And the water keeps coming.
The utility estimates it may be eight years before radiation levels fall enough to let workers start the main task of removing 260 tons of melted nuclear fuel. That process took more than a decade at the U.S. accident on Three Mile Island, a partial meltdown at a single reactor containing about one fifth the amount of fuel at Fukushima.
“The things they have to do now are measured in years rather than days and months,” Gregory Jaczko, the former chairman of the U.S. Nuclear Regulatory Commission, said in a telephone interview. “What they have to do is very, very challenging. It’s hard to put a grade on how well it’s going because it’s so unprecedented.”
Still, little more than a year after the plant’s stricken reactors were brought into a controlled state known as cold shutdown, progress is visible.
A steel structure is being built to hold a crane for removing Unit 4’s spent fuel and Unit 1 is covered in a vinyl-coated shroud to help contain its radiation. Workers are preparing to drive a steel wall into the seabed to prevent water leaking from the plant into the ocean.
At Unit 4, which avoided a meltdown, steel braces have been added to reinforce a storage pool that holds 1,533 spent fuel rods five floors above the ground. By November workers will start to lift out the assemblies, removing one more source of risk.
“We have a lot of damaged fuel but we’ll make every effort to maintain safety while we push on with the decommissioning process,” site manage Takeshi Takahashi told reporters.
‘New Nuclear Age’
A poster at Dai-Ichi’s command center reads: “This is not the end. This is the beginning of a new nuclear age.”
Radiation danger prevents workers from approaching a tangle of metal and upturned cars surrounding Unit 3, which was ripped apart by a hydrogen gas explosion after the tsunami. Remote controlled cranes are used to pull steel and concrete rubble from the top of the structure.
Dosimeters register a jump to 1.7 millisieverts during a bus ride past the rubble, indicating a 60-minute exposure would equal eight months of natural radiation. It will be years before even robots can work inside the steel- and concrete-encased core, according to Arnie Gundersen, chief engineer at Burlington, Vermont-based energy consultant Fairewinds Associates Inc.
“Unit 3 is in a condition that none of us has ever imagined,” he said by phone. “The entire structure is inaccessible to human beings right now.”
Mountain of Waste
While clearing debris helps reduce radiation levels, it’s also filling the plant with toxic waste for which the utility has no ultimate disposal plan. More than 73,000 cubic meters of contaminated concrete, 58,000 cubic meters of irradiated trees and bushes, and 157,710 gallons of toxic sludge has built up, according to the utility.
Then there’s the water.
Tanks of it now cover an area equal to 37 football fields and the utility is clearing forest to make room for more. Some 400 tons of ground water each day seeps into reactor buildings and is contaminated.
There are 480 cesium-clogged filters, each weighing 15 tons, already warehoused in what the utility calls temporary storage.
“These filters will have to be stored for 300 years because cesium has a 30-year half-life and the rule of thumb is 10 half-lives,” Fairewinds’ Gundersen said.
Tokyo Electric has built a second plant it hopes will be able to extract the more than 60 radio-nucleotides remaining in the water after cesium is removed. Assuming the equipment works as intended, it will generate yet more contaminated filters.
Still, even in the best case, Tokyo Electric acknowledged the system won’t be able to strip out tritium, a radioactive hydrogen isotope. Tritium contamination will make it difficult to convince local fishing unions to agree to any release into the ocean as no matter how diluted the actual water molecules remain radioactive.
Tokyo Electric has “no plans” for what to do with the water once its filtered, plant manager Takahashi said. It will probably wind up back in tanks, spokesman Yoshikazu Nagai said, standing in front of the new treatment facility.
Some 700 vehicles leaving the plant each day are scanned for radiation. One in ten exceeds safety standards and must be washed, adding a few more buckets to the deluge of toxic water.
To contact the reporter on this story: Jason Clenfield in Tokyo at firstname.lastname@example.org
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