In the 1950s, U.S. scientists and policymakers were excited about a new form of carbon-free energy--although not one that's generally considered green today.
It was nuclear power.
Multiple accidents and concerns over long-term disposal of radioactive fuel essentially killed nuclear-power development in the U.S., but some researchers believe it's poised to make a comeback.
A new startup called Transatomic plans to market a reactor based on a design from the golden age of atomic research--and it's fueled by the waste of current reactors.
This "back to the future" approach relies on a "molten salt" reactor type that hasn't seen the light of day in roughly 50 years, according to a Brookings Institution write-up of the project.
All nuclear power sources currently in operation use light water reactors (LWR), which use uranium-studded rods to heat water. In contrast, the molten salt reactor uses liquid uranium for fuel.
Molten Salt Reactor Experiment at Oak Ridge National Laboratory [Wikipedia]
A prototype was switched on at Oak Ridge National Laboratory in 1965, and the Air Force even investigated using a similar design for a nuclear-powered plane.
However, the molten salt reactor was eventually discarded, in part because it required uranium enriched to levels far beyond the legal limit set to prevent use of the material in nuclear weapons.
Now, Transatomic believes it can update the design to run on the used uranium fuel rods of other reactors--producing clean power while consuming waste.
Climate change to trigger nuclear rebirth?
No new commercial reactors have been built in the U.S. in over 30 years, but concerns about climate change could fuel a resurgence of the industry.
While nuclear power remains controversial, reactors produce no greenhouse-gas emissions, and aren't dependent on weather conditions as are most renewable sources.
Right now, nuclear power accounts for roughly 20 percent of the electricity generated in the U.S.--more than solar, wind, or hydroelectric generation.
Last year, the Intergovernmental Panel on Climate Change issued a call for 400 more reactors--a near doubling of the current global total of 435--as part of an overall effort to bring more carbon-free energy sources online faster.
That, in turn, could allow electric cars to be recharged on carbon-free electricity--lowering the carbon footprint of driving passenger vehicles enormously against those charged from today's mixed-source electric grids.
Many countries remain leery of nuclear power because of its potential for accidents--such as the recent debacle at Japan's Fukushima Daiichi plant in 2011.
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If the new reactors continue to use the traditional light-water design, they will also produce massive amounts of nuclear waste.
Even after they're no longer suitable for use in a reactor, the uranium rods can remain radioactive for up to 100,000 years. The spent rods are typically sealed in casks and buried.
Transatomic claims its molten salt reactor could solve both of these problems.
Simulations estimate the reactor would produce just 2.5 percent as much waste as a comparable LWR--meaning a large enough network of them could consume the current stockpile of nuclear waste over time.
Containers holding spent nucleat fuel [Nuclear Regulatory Commission photo]
The reactor also doesn't require an externally-powered coolant pumps, theoretically making it safe in the event of a power failure like the one that triggered the Fukushima disaster.
However, as with any other experimental technology, simulations and estimates don't always translate to real-world results.
At the very least, Transatomic will need regulatory approval to test its design before commercial versions can even be considered.
Considering current popular feelings about nuclear power, that--not to mention getting funding--will likely be a challenge.