“The real challenge is going to be getting in and installing it safely, in a way that you’re not exposing people to hazards,” Mr. Yarmak said, adding that much of the work will likely have to be done remotely, via automated equipment.
Even at Pennsylvania’s Three Mile Island, where the reactor vessel remained intact after a partial meltdown in 1979, removing the fuel by remote-controlled machinery was a tricky engineering feat. Although great strides have been made in robotics since then, damage to the containment vessels at the Japanese site renders the effort much more complex.
Contrary to any speculation the ice wall will cost far more than the estimated $320-million, Mr. Sopko said the price tag actually seems “astronomical” – his Aquarius project cost about $30-million in 1998 – but added that the steep cost might be attributed to dealing with safety concerns.
“Production could be very slow because there’ll be limited time that people can be out there – workers will have to come back in and decontaminate,” he said. “The biggest challenge will be the protection of the workers putting this thing in.”
Beyond workplace safety, critics have raised several concerns about Japan’s announcement this week – from the ice wall’s lifespan to power issues to the timeline to the reliability of the ice wall to begin with.
For Mr. Yarmak and Mr. Sopko, though, none of those worries seem particularly well-founded.
Typically, ice walls aren’t conceived to last more than a few years, and the Fukushima decommissioning process is expected to take about four decades. But Mr. Yarmak said even the Tennessee project – designed to last just six years – could have gone on at least another 20 before needing new machinery. The pipes themselves, he said, could have lasted 50 to 100 years.
Mr. Sopko added that there are a few frozen-earth projects in the U.S. that have been designed to store liquid propane underground “almost permanently.”
As for the concern that the project will require such electrical heft that outages will be inevitable, both experts pointed out it takes a long time for an ice wall to thaw. Mr. Yarmak, for example, said he ran a 10-day outage test on the Tennessee site and found he lost only 1 per cent to 2 per cent of the wall in that time.
The project is expected to be completed in less than two years – a time frame both Mr. Yarmak and Mr. Sopko said is realistic, even with safety issues. Mr. Yarmak finished the Tennessee wall in four months, while Mr. Sopko said the Ontario ring took about a year to finish. (It was never activated because a drop in gold prices made it uneconomical, he said.)
Mr. Sopko said he was initially concerned that the groundwater near the Fukushima plant might be travelling too fast, causing technical issues when it meets the ice wall.
“You can really run into problems if the water is moving faster than one metre per day,” he said. “My understanding is it’s only moving 10 centimetres a day, and that’s well within the capacity of this particular type of refrigeration system.”
The Chernobyl model
Critics such as Harutoshi Funabashi, a Hosei University sociologist who led an academic review of the recovery efforts post-disaster, said Japan’s plan is “just a tactic to avoid taking responsibility” and facing an angry public.
He and others say Japan should consider other options, including the approach taken by the former Soviet Union in the aftermath of the 1986 Chernobyl disaster. Back then, the government essentially capped the battered reactors with concrete and declared the most contaminated towns off-limits for a generation.
“Admitting that no one can live near the plant for a generation would open the way for all sorts of probing questions and doubts,” Mr. Funabashi said, explaining his theory for the government’s plan.
Mr. Sopko pointed out that the large amounts of groundwater under the plant mean that pouring concrete wouldn’t contain the spread of radiation. “It wouldn’t solve the sub-surface problem,” he said.
Japanese officials said giving up on a large portion of Fukushima is not an option in a densely populated country where land remains a scarce commodity. But they also suggested that the reason for eschewing a Soviet-style option may be the fear that failure could turn a wary public even more decisively against Japan’s nuclear industry.
“If we just buried the reactors, no one would want to see the face of another nuclear power plant for years,” said Shunsuke Kondo, chairman of the government’s Atomic Energy Commission.