The news coming out of Japan about attempts to clean up the wrecked Fukushima nuclear power station and contain the tons of radioactive water leaking into the ground and the Pacific Ocean is not reassuring.

Now the Japanese government is pledging nearly half a billion dollars to try to freeze the ground under the melted down reactors, to try to control the leaks that way. It sounds like a desperation play, says Edwin Lyman, a senior scientist with the Union of Concerned Scientists.

"The plant is leaking radioactive material every day into the ocean, and right now the plant’s operator Tepco is unable to stop it," he said.

The frozen wall would, essentially, create an artificial permafrost barrier around the plant.

"The idea is to embed pipes about 100 feet deep in a ring around the damaged reactors and run coolant through those pipes, so essentially you’re running a refrigeration unit that would slowly freeze the soil and would turn into an impenetrable block of ice," Lyman said.

This barrier, depending on how long it takes to clean up the reactors, might have to be in place for decades. While the idea sounds fanciful, it has precedence. Previously it's been used during mining operations, though not, Lyman said, with a situation "this delicate."

"And not for the kind of time scale we’re talking about. So in effect it really is uncharted waters in regards to Fukushima," Lyman said.

Ironically, officials will need significant amounts of power to run this new refrigeration system — power that is in short supply after of Japan's nuclear reactors were shutdown in the wake of the Fukushima disaster.

"Right now, Japan depends heavily on imported natural gas for a lot of its electricity," Lyman said.

Tepco has tried several other options to contain the leak, but everything seems to come up short. Lyman said it's fair to call this effort a desperation measure.

"There aren’t any good options in dealing with this mess. You just have to come up with a way to divert groundwater so that it does not run through the site and pick up radioactivity, and there are only a few ways you can do that," he added.

Japan's struggle to keep the Fukushima situation under control has raised uncomfortable questions about some U.S. nuclear plants as well. Entergy Corporation has announced plans to cost the Vermont Yankee nuclear power plant next year.

"The economics of nuclear power in the United States is very precarious right now. The price of natural gas is extremely low, primarily because of the availability of gas from fracking. And the nuclear power plants that are running today are simply unable to compete," Lyman said.

The U.S. Nuclear Regulatory Commission is also making changes in light of the situation in Fukushima, particularly at plants like Vermont Yankee, which is designed in the same way as Fukushima.

"Even though the industry has tried very hard to limit the scope of those changes, there still is a significant price tag associated with them," Lyman said. "Entergy did cite the cost of post-Fukushima upgrades as one of the reasons why they’re shutting the plant down."

Lyman says Americans don't really have to worry about the sort of earthquake-tsunami double-whammy hitting a U.S. nuclear plant, but there are other risks that could prove just as catastrophic.

"The biggest threat is actually from upstream dams. There are a few dozen plants on rivers or lakes, which are vulnerable in the event of a dam failure, to being flooded in a very short period of time, as happened in Fukushima," he said.