Is it safe? That’s what most people — brought up on Three Mile Island, Chernobyl and The Simpsons — want to know about nuclear power. And for the most part, the answer is yes. Accidents are rare, and those that have occurred — including the partial meltdown in Fukushima, Japan, in 2011 — have resulted in few deaths. On a megawatt-per-megawatt basis, nuclear kills fewer people than almost any other source of electricity — especially compared with air pollution from coal, the single biggest supplier of electricity in the U.S., which contributes to the deaths of 14,000 Americans each year. And nuclear energy, unlike every other form of electricity — save hydro and renewables, doesn’t contribute to man-made climate change.

But while nuclear energy supplies about 13% of global electricity — and dozens of new reactors are being built in countries like China, India and Russia — in the U.S. and much of the rest of the developed world, nuclear energy is in retreat, with new reactors on hold and aging ones being retired. And while fears of accidents and radioactivity clearly play a role in that decline, cost is an even bigger factor. Existing nuclear reactors produce inexpensive electricity, but the price of a new nuclear plant keeps ballooning, with reactors running billions over budget, forcing some utilities to abandon projects in midconstruction. Nuclear plants — most of which are derived from Cold War–era designs — actually became more expensive as they scale up, with larger plants requiring bigger and stronger containment domes that used expensive concrete and steel. Outside of France, nuclear plants largely weren’t standardized, which meant that nearly every reactor was produced bespoke — much like buying a suit from a tailor instead of off the rack. Add in the fact that the economic costs of an accident could be enormous even if the human costs weren’t — the Fukushima meltdown, which killed no one, could cost more than $100 billion — and you have a very expensive way to generate electricity. With the fracking revolution pumping out cheap natural gas in the U.S. and renewables preferred in much of Europe, nuclear will remain in decline in the developed world unless it can get cheaper.

By Bryan Walsh

Read full article on Time: Science & Space