Mini-nuclear plants the next frontier of US power supply -- or the next Solyndra?

A boon to the economy? Or a boondoggle?

That's the debate raging over a new nuclear technology that -- depending on your perspective -- is either a game-changer in electrical generation, or a failure-in-the-making that will fleece taxpayers for a half-billion dollars.

The technology, called "small modular reactors," will be the centerpiece of an entirely new way of thinking about nuclear power. They are much smaller than what traditionally has been built in this country -- producing about one-sixth the power. They'll also cost less -- about $1 billion-2 billion apiece, compared with $10 billion-$15 billion for a large plant.

Typical nuclear units produce between 1,000 and 1,400 megawatts of electricity. SMRs, as they're called, top out at about 180 megawatts. The plan is to build them in two-packs, for a total of 360 megawatts, which is right around the output of a coal-fired unit.

For supporters, the goal of replacing coal-fired plants is key. In his June speech on climate change, President Obama talked about shutting down dozens of older coal plants, which left open the question of how that electricity would be produced.

Charlotte, N.C.-based Babcock and Wilcox is betting millions of dollars that the answer to that question -- at least in part -- is small modular reactors.

"Small modular reactors are all about taking the risk out of the equation for nuclear," said Christofer Mowry, president of B&W's mPower division. "And that's what the industry wants -- they want to de-risk nuclear. They like nuclear because nuclear offers what no other source of energy does, which is basic, reliable, clean energy."

B&W has taken the lead in the development of SMRs with its mPower design. Eighty-five feet tall and 13 feet wide, it incorporates several systems into one unit. The unit is built in a factory, instead of in the field, and then shipped to the site on a truck.

B&W officials describe the system as more cost-effective and more reliable. Traditional nuclear plants are incredibly complex designs with a degree of risk in construction. mPower plants are relatively simple, replicable units. It's not quite mass production, but it's also not reinventing the wheel every time a plant is built. And the mPower design includes several new safety systems, including passive cooling in the event of a Fukushima-type loss of power.

"What we did was we actually analyzed the events of Fukushima as they occurred and laid it against the mPower design shortly after the event happened," said Jeff Halfinger, chief of technology development for mPower. "And mPower would have ridden out of Fukushima."

What really separates SMRs from traditional nuke facilities is that the plant is built almost entirely underground. The surface profile is about the size of a Walmart.

Bill Johnson, president of the Tennessee Valley Authority, is impressed. "On a big plant you would like about 300 acres. Here you can actually build the plant on about 40 acres," Johnson told Fox News. "So it's a lot less land use, it's a lot less water use, easier to build transmission lines to it. The small economy of scale may actually be helpful to us."

The TVA wants to be the first utility to build an SMR plant. Geologic testing is underway at a site on the Clinch River, not far from the Oak Ridge National Laboratory. But already the process is falling behind.  TVA was expected to apply for a construction permit last year. But that application has been delayed until 2015 at the earliest.

That's not the only controversial point with SMR's. The federal government has pledged more than $500 million to help develop the technology.  B&W has so far received $79 million for R&D, with the possibility of an additional $150 million.

That's not sitting well with the watchdog group Taxpayers for Common Sense. It points to the long history of expensive failures in the nuclear industry, backed by 60 years of subsidies.

Ryan Alexander, president of the group, sees the potential for a nuclear version of Solyndra, the solar power company that went belly up after taxpayers poured a half-billion dollars into the company.

"There are a lot of cost questions that we don't know anything about, and it just seems like this is not going to happen without it being just incredibly expensive. So we don't want to keep putting taxpayer dollars into this idea that may or may not happen," she told Fox News.

Alexander points to the fact that the industry still has no idea how much electricity generated from SMRs will really cost and whether the economics of it even work. She gave the government a "Golden Fleece" award for the subsidy plan.

TVA CEO Bill Johnson says electricity from SMRs will likely be in the same cost range as traditional nukes. And he insists this won't be another Solyndra.

"Ugh, no," he told Fox News. "We're going to watch this closely, we're going to work hard at this, we are going to stop every point and make sure it makes sense."

Supporters of SMR's say the idea makes good economic sense, particularly if it is exported overseas. They see plenty of potential for job creation with a technology that keeps America at the forefront of nuclear development.

"This is a way that keeps us in the industry in an innovative way, keeps our leadership in an operating space. I think it has great potential not only in the energy space but internationally," Johnson said.