• Humanity may face an energy crisis as the world’s population rapidly grows.
  • Nuclear power plants can generate bountiful, carbon-free electricity, but their solid fuel is problematic, and aging reactors are being shut down.
  • A Cold War-era liquid-fueled reactor design could transform thorium — a radioactive waste from mining — into a practically limitless energy source.
  • US engineers proved such a system works during the 1960s. However, the military canceled the project and it was nearly forgotten.
  • Companies and governments are now trying to revive and evolve the design, but development costs, regulations, and nuclear-weapons concerns all pose hurdles.

The lifeblood of modern civilization is affordable, free-flowing energy.It gives us the power to heat our homes. Grow and refrigerate food. Purify water. Manufacture products. Perform organ transplants. Drive a car. Go to work. Or procrastinate from work by reading a story about the future of energy.Today’s cheap, bountiful supplies make it hard to see humanity’s looming energy crisis, but it’s possibly coming within our lifetimes. Our numbers will grow from 7.36 billion people today to 9 billion in 2040, an increase of 22%. Rapidly developing nations, however, will supercharge global energy consumption at more than twice that rate.Fossil fuels could quench the planet’s deep thirst for energy, but they’d be a temporary fix at best. Known reserves may dry up within a century or two. And burning up that carbon-based fuel would accelerate climate change, which is already on track to disrupt and jeopardize countless lives.Meanwhile, renewable energy sources like wind and solar, though key parts of a solution, are not silver bullets — especially if the world is to meet a 2050 deadline set by the Paris Agreement. Energy from fusion is promising, but it’s not yet proved to work, let alone on a commercial and competitive scale.Nuclear reactors, on the other hand, fit the bill: They’re dense, reliable, emit no carbon, and — contrary to bitter popular sentiment — are among the safest energy sources on earth. Today, they supply about 20% of America’s energy, though by the 2040s, this share may drop to 10% as companies shut down decades-old reactors, according to a July 2016 report released by Idaho National Laboratory (INL).The good news is that a proven solution is at hand — if we want it badly enough.Manhattan Project chemist Glenn Seaborg sits at the controls of the Molten Salt Reactor Experiment in 1968.Frank Hoffman/Oak Ridge National Laboratory; Flickr (public domain)Called a molten-salt reactor, the technology was conceived during the Cold War and forgoes solid nuclear fuel for a liquid one, which it can „burn” with far greater efficiency than any power technology in existence. It also generates a small fraction of the radioactive waste that today’s commercial reactors — which all rely on solid fuel — do.And, in theory, molten-salt reactors can never melt down.”It’s reliable, it’s clean, it basically does everything fossil fuel does today,” Kirk Sorensen, the chief technology officer of nuclear-energy startup Flibe Energy, told Business Insider. Sorensen was speaking during an episode of Business Insider’s podcast Codebreaker, which is produced with National Public Radio’s „Marketplace. „”And it does a whole bunch of things it doesn’t do today, like make energy without emitting carbon,” he added.A sample of thorium metal in a glass vial. W. Oelen/Wikipedia (CC-BY-SA 3.0)What’s more, feeding a molten-salt reactor a radioactive waste from mining, called thorium (which is three to four times more abundant than uranium), can „breed” as much nuclear fuel as it burns up.Manhattan Project scientist Alvin Weinberg calculated in 1959 that if we could somehow harvest all the thorium in the Earth’s crust and use it in this way, we could power civilization for tens of billions of years.”The technology is viable, the science has been demonstrated,” Hans Gougar, a nuclear physicist at INL, told Business Insider.Demonstrated, because government scientists built two complementary prototypes during the 1950s and ’60s.They weren’t good for making nuclear weapons, though, so bureaucrats pulled funding for the revolutionary energy technology. The last working molten-salt reactor shut down in 1969.Today, entrepreneurs such as Sorensen are working tirelessly to revive and modernize the technology. So are foreign governments like India and China.China now spends more than $350 million a year developing its variation of the Cold War-era design.The story of how we got here is neither short nor simple, but it explains why Sorensen and others are betting big on humanity’s coming „Thorium Age” — and why the US continues to stumble at its dawn.The argument for nuclear energyThe Three Mile Island Nuclear Plant in Middletown, Pennsylvania. Jeff Fusco/Getty ImagesIts brutalist architecture may not be sexy, but nuclear energy unlocks a truly incredible source of carbon-free fuel. Ounce per ounce, uranium provides roughly 16,000 times more energythan coal and creates millions of times less pollution.The argument to support growth in nuclear energy is so clear to James Hansen, a seasoned climatologist and outspoken environmentalist, that he passionately advocates for the use and development of the technology.”To solve the climate problem, policy must be based on facts and not on prejudice. The climate system cares about greenhouse gas emissions — not about whether energy comes from renewable power or abundant nuclear power,” Hansen and three other well-known scientists — Ken Caldeira, Kerry Emanuel, and Tom Wigley — wrote in an editorial for The Guardian in 2015.”Nuclear energy can power whole civilisations, and produce waste streams that are trivial compared to the waste produced by fossil fuel combustion,” they wrote. „Nuclear will make the difference between the world missing crucial climate targets or achieving them.”Climate science aside, the economics of nuclear energy are enough of a draw to make the technology worthwhile.Today, the industry is already profitable, albeit well subsidized. Still, if you level the energy playing field against other power sources by taking into account government subsidies and tax breaks, capital costs, fuel costs, and other factors that affect the price-per-megawatt-hour of a power plant, nuclear energy remains a financial win in the long run.Nuclear power’s 2016 levelized costs make it about twice as cheap as natural gas „peaking” plants (which fire up to meet sudden peaks in energy demand). Nuclear also beats the overall cost of many coal-fired power plants. And that’s before you account for the extraordinary hidden costs of fossil fuels against public health and the environment, including particulate pollution (which kills tens of thousands of people a year) and exacerbating climate change.Nuclear also wins financially against solar rooftops, many fuel-cell energy schemes, and some geothermal and bioenergy plants.That isn’t to say that current nuclear power plants are flawless. However, they’re irrefutably amazing power sources, currently meeting one-fifth of the US’s energy needs with just 61 power plants. They’re also incredibly reliable, always-on sources of baseload electricity, heat, and medically useful radioisotopes.Yet great titans fall hard, and the reasons why are key to the continued delay of the Thorium Age.Why nuclear energy is collapsing in AmericaWhile new reactors are planned or are coming online soon, many have stalled and the industry has stagnated, with eight of the US’s 99 decades-old reactors planned for shutdown by 2025.What gives?SubsidiesREUTERS/Stringer Flibe Energy’s Sorensen partly blames aggressive government subsidization of wind and solar energy, which leads to the problem of negative pricing.”We’ve created rules that disturb the energy market substantially,” Sorensen said. „The first rule is that whenever wind and solar come online, we have to take the power. That’s called grid priority. The second rules is, they’re paid no matter how much power they make.”Sorensen characterized this as the „murder” of nuclear energy, since those plants can’t be shut on and off quickly. He also said this is hurting the environment by causing companies to invest more heavily in gas plants (which can be ramped up and down quickly).”These two put together create negative prices, and if you’re a nuclear power-plant operator, and you’re trying to obviously make money selling power to the grid and the prices go negative for large portions of the day, that’s economically unviable,” he said. „That’s what’s causing reactors to get shut down.”But other issues are kneecapping nuclear too.Time and costtrojan nuclear power plant demolition oregon rick bowmer AP_060521021273A cooling tower of the Trojan nuclear power plant is demolished on May 21, 2006. The decommissioning process can take decades.Rick Bowmer/Associated PressEnergy sources such as hydroelectric and wind are still cheaper than nuclear, and a fracking boom has fueled investment in natural-gas-fired power plants.As a result, nuclear is having a harder time finding a seat at the energy-pricing table.Reactors also take many years and billions of dollars to permit, build, and license for operation: They’re exceedingly large and complex works of engineering (though you only need a high school diplomato operate one once they’re finished).Old age The average US reactor is about 35 years old. They can run for decades with constant maintenance. The Oyster Creek nuclear generating station outside of New York City, for example, has operated since 1969. But many are being eyed for shutdown, and once they’re shut off, reactors can take more than a decade to decommission, demolish, and bury. A dysfunctional uranium fuel cycle in the US has not helped, where just 3% to 6.5% of solid uranium fuel is burned up — and the remaining 93% to 97% is treated as radioactive waste and not reprocessed and recycled.FearA nuclear-energy demonstrator. Matt Cardy/Getty ImagesThen there is society’s pervasive anxiety toward nuclear power, often amped to irrational levels.While events such as Three Mile Island, Chernobyl, and the Fukushima Daiichi disaster stand out in people’s minds, the reality does not match up by a long shot.”Nuclear radiation ticks all the boxes for increasing the fear factor,” David Spiegelhalter, a statistician at Cambridge University, told New Scientist after the Fukushima disaster in 2011:”It is invisible, an unknowable quantity. People don’t feel in control of it, and they don’t understand it. They feel it is imposed upon them and that it is unnatural. It has the dread quality of causing cancer and birth defects.”But as Spiegelhalter, Sorensen, and others have said, the actual safety record of nuclear power is remarkable.Fukushima’s reactor meltdowns killed no one, according to a 2013 World Health Organization report. Even in „the two most affected locations of Fukushima prefecture,” people in the first year would receive only two to three CT chest scans’ worth of radiation exposure.”Let me throw out other names you might not be familiar with: San Bruno. Banqiao Dam,” Sorensen said, referring to the two accidents that killed eight (in a 2010 California gas-line explosion) and as many as 230,000 people (in a series of 1975 Chinese dam collapses), respectively.”These are catastrophic incidents with hydropower and natural gas that really did result in large losses of human life,” he said. „And yet the public doesn’t have a terror of hydroelectric power or natural gas.”What does the data say about nuclear energy’s safety?Andrew LeatherbarrowMeasuring immediate deaths against gigawatts of electrical power is a typical way to assess the safety of energy sources, and a 2010 analysis by the Organization for Economic Cooperation and Development (OECD) used this.But adding in incidental deaths that occur later, such as 9,000 estimated cancer fatalities from Chernobyl (which the OECD left out), does change the numbers, as does including pollution deaths and incidental Banqiao Dam deaths.In a more apples-to-apples comparison, New Scientist crunched the numbers. That maximum death-toll estimates from that analysis show:

  • Natural gas is 1.3 times as dangerous as nuclear
  • Coal is 27 times as dangerous as nuclear
  • Hydroelectric is 46 times as dangerous as nuclear

In absolute terms, nuclear energy prevents about 80,000 air-pollution-related deaths a year, according to a 2013 study. Groups with antinuclear positions, such as Greenpeace, have struggled to spin these numbers.”Nuclear power has consistently been proven to be the safest and most effective form of power that we have today, and by using thorium nuclear power, we can take that admirable safety record and go even further,” Sorensen said.But grasping the promise and potential perils of a thorium-powered future, or any other atomic-energy scheme, means you’ve got to know a thing or two about nuclear physics.