Nuclear Power Is Too Safe to Save the World From Climate Change
LATER THIS YEAR, a nuclear power reactor will open in the US for the first time in two decades. But this reactor, called Watts Bar Unit 2—one of two near Spring City, Tennessee—isn’t quite new. Most of it was built in the 1970s and ’80s alongside Unit 1, which came online in 1996 and has performed flawlessly. The two reactors are essentially identical in terms of safety, technology, and output. But there’s been one major advance in the 20 years separating their openings: widespread acceptance of fossil fuels’ role in climate change, and the urgent need to wean the economy from it.
In the years that Watts Bar 2 lay fallow, policymakers and climate strategists have struggled to figure out what the future of renewable energy will look like. They have three options: find a way of cleaning up coal, build batteries capable of storing energy from capricious renewables, or go nuclear. Each has benefits and drawbacks. But nuclear is a strong contender because it is the only technology that actually exists. The Watts Bar reactors will provide power to 1.5 million households, and their only greenhouse gas emissions will come from the cars employees use to commute.
That’s a good deal, but still. Show a crowd a pair of cooling towers, and at least some of them will see an atomic apocalypse featuring three-eyed fish, leafless forests, and hospital-gowned Soviet defectors with skin like glistening mayonnaise. Nuclear power may be clean, but people still question whether it is, or ever will be, safe enough.
Those fears may be moot. Safety concerns didn’t delay construction on Watts Bar Unit 2 for so many years. Economics did. For all that fear, nuclear power still has the safest track record of any power source.
Nuclear energy sources are dangerous because they emit radiation—particles and energy shed from unstable molecules trying to calm down. “Those radioactive missiles can hit the human body and damage cells or DNA,” says David Lochbaum, director of the Union of Concerned Scientist’s nuclear safety project. Enough radiation will give you cancer, or possibly even pass genetic mutations on to your kids. Too much can kill you outright.
But plants like Watts Bar don’t release much radiation into the environment. Inside, radioactive material heats water, which turns into steam, which spins the enormous turbines that generate electricity. Plants regularly release some of that water and steam at rates prescribed by the US Nuclear Regulatory Commission, and if you live downriver or downwind of one, the radiation within will raise your chances of developing a tumor by just one tenth of one percent. You’re far more likely to grow a tumor because you sneak a cigarette now and again.
But you aren’t afraid of routine releases. You’re terrified of another Three Mile Island, Fukushima, or Chernobyl.
These disasters were the result of a meltdown, which occurs when something impedes a reactor’s ability to cool the fuel. The US, where nearly 20 percent of electricity comes from 99 nuclear plants, uses uranium. Older reactors—which is every reactor in the US, including Watts Bar Unit 2—use electric pumps to move water through the system. The Fukushima disaster showed what happens it you have pumps but no power to use them. Newer generations rely on gravity instead, draining cooling water from elevated storage tanks to send it through the reactor core.
Those updates mean serious nuclear accidents are becoming ever more rare. Since Three Mile Island in 1979, the Nuclear Regulatory Commission found that the rate of shut-down-the-reactor-level problems has dropped from 2.5 per plant per year to around 0.1 (One such happened on March 29 in Washington). Even Three Mile Island wasn’t the disaster it could have been, because of that plant’s layers of redundant protection.