This one is from Five Thirty Eight:

The age of the nuclear fleet is partly to blame. That’s not because America’s nuclear reactors are falling apart — they’re regularly inspected, and almost all of them have now gone through the process of renewing their original 40-year operating licenses for 20 more years…

Instead, it’s the cost of upkeep that’s prohibitive. Things do fall apart — especially things exposed to radiation on a daily basis. Maintenance and repair, upgrades and rejuvenation all take a lot of capital investment. And right now, that means spending lots of money on power plants that aren’t especially profitable. Historically, nuclear power plants were expensive to build but could produce electricity more cheaply than fossil fuels, making them a favored source of low-cost electricity. That changed with the fracking boom, Morgan told me. “Natural gas from fracking has gotten so cheap, [nuclear plants] aren’t as high up in the dispatch stack,” he said, referring to the order of resources utilities choose to buy electricity from. “So many of them are now not very attractive economically…”

Morgan and other researchers are studying the economic feasibility of investment in newer kinds of nuclear power plants — including different ways of designing the mechanical systems of a reactor and building reactors that are smaller and could be put together on an assembly line. Currently, reactors must be custom-built to each site. Their research showed that new designs are unlikely to be commercially viable in time to seriously address climate change. And in a new study that has not yet been published, they found that the domestic U.S. market for nuclear power isn’t robust enough to justify the investments necessary to build a modular reactor industry.