The Download: next-gen nuclear, and the data center backlash

The popularity of commercial nuclear reactors has surged in recent years as worries about climate change and energy independence drowned out concerns about meltdowns and radioactive waste. The problem is, building nuclear power plants is expensive and slow. A new generation of nuclear power technology could reinvent what a reactor looks like--and how it works. Advocates hope that new tech can refresh the industry and help replace fossil fuels without emitting greenhouse gases. Here's what that might look like . Next-gen nuclear is one of our 10 Breakthrough Technologies this year.