I used to oppose nuclear, but I now think it's a worthwhile backup, or perhaps one strand in a diversified approach to getting off fossil fuels. There is, sadl

I used to oppose nuclear, but I now think it's a worthwhile backup, or perhaps one strand in a diversified approach to getting off fossil fuels. There is, sadly, no one single technology that can replace fossil fuels for even any one major category of use (electricity, industrial, buildings, transport). We're going to end up with a massively more complicated energy supply system. In this context I think it's still worth pursuing nuclear. The cost argument has only arisen recently. As late as 2010 nuclear was competitive, or at least not obviously uncompetitive apart from its massive regulatory burden. It seems to me that a lot of nuclear's costs arise from the "as low as reasonably achievable" doctrine (ALARA), which in turn is founded in the "linear no threshold" theory (LNT) of the effects of radiation. LNT is falsified by the health statistics of the Denver population vs the coasts, and many other real-world observations. If fission had fixed, scientifically determined thresholds and performance standards to work to, and a less hostile regulatory environment (removing the veto of NIMBYs), it would really interesting to see how it competes. It can scale up to the necessary scale in 30 years. Fusion, on the other hand, can't conceivably help us with the transition in the time we have available. It'd be best to park it for 50 years and redeploy those physics Ph. D.s into material science for photovoltaics, batteries, electrolysis, and fuel synthesis.