nuclear-news

Steps in cleaning up Fukushima

AUDIO Cleaning Up Fukushima: A Challenge To The Core : NPR, 13 April 2011, “…….Nuclear engineers working at the Japanese plant are dealing with two problems at the same time: They are working to fully stabilize the plant’s reactors, and they are trying to control the release of radioactive material.
It could take weeks or months to stabilize the reactors. And containing and cleaning up the radioactive material could take at least 10 years, at a cost of more than $10 billion. Even though many of the details about what’s happening at the reactors are not known, experts can predict the tasks ahead for workers.

Back in 1979, nuclear engineer Lake Barrett coordinated cleanup at Pennsylvania’s Three Mile Island reactor for the Nuclear Regulatory Commission. He breaks down the cleanup challenge to the basic elements of ancient Greece. The Greeks had fire, air, water and earth. At Fukushima, it’s pretty much the same: energy, air, water and solids.

“So if you go back to the four basic principles, what the engineers are doing in Fukushima is first they have to deal with energy dissipation — that is the cooling of the decay products in the core — keep the core cool,” Barrett says……

For now, there’s a watery mess at the plant.

“In the case of Three Mile Island, we had about half a million gallons of very highly radioactive water in the basement of the containment building,” Barrett says. “It was about 10 feet deep. They’re facing the same situation in Fukushima, but they have three of these cores that have severe damage to them, so they probably have tens of millions of gallons of the same highly radioactive water that they’re dealing with.”…..

Once the energy, gas and water aspects of the nuclear crisis are under control, the most highly radioactive materials — the solids in the reactor cores — remain. Just getting to them is a problem……

Leo Lessard, a nuclear engineer at the French company Areva, says just getting to the cores at Fukushima Dai-ichi is going to be much more difficult than it was at Three Mile Island. For starters, the tops of two buildings have collapsed, so that debris will have to be cleared.

“A lot of that material is probably very radioactive, so there will have to be shielding and other precautions incorporated in order to protect workers who have to do some manual operations in those areas,” Lessard says….

“In that case, you have a tremendously high radiation field, as opposed to having it underwater, where the water is providing complete shielding,” Lessard says. He expects the cleanup to take more than a decade.

Barrett says to count on cleanup costing $10 billion. Engineers can break the problem down to the basics, and they know how to do each individual step — but nobody’s ever tried a nuclear cleanup on this scale before.
Cleaning Up Fukushima: A Challenge To The Core : NPR

April 13, 2011 - Posted by Christina Macpherson | Uncategorized