> we don't need more base power, which is the only thing nuclear is capable of providing
This is wrong both ways. First, we need more base load power because most of the existing base load is fossil fuels which we have to stop using.
Second, it's very difficult to have "too much" base load generation once you electrify transportation because the extra base load generation is useful to satisfy normal demand when demand would otherwise outstrip supply and useful to charge vehicle batteries when it doesn't.
> Nuclear is the most expensive form of energy generation possible despite being a supposedly "mature" technology.
This was done on purpose. There is nothing inherent in the technology that makes it expensive. "Generate heat to generate steam to generate electricity" is fundamentally the same for nuclear and coal or natural gas, so the only explanation for the former having a significantly higher cost is regulatory, which was intentional and could be different given a different intent.
> Nuclear is sold as a "green" and "carbon neutral" energy source - a claim only made possible by completely ignoring the massive carbon impact of its supply and operations chain.
Nuclear has a low carbon impact even if you include its supply and operations chain. Also, most of those things apply to any form of power generation (you also have to manufacture and transport solar panels), and most of the CO2 emissions required are from energy and transportation, so if your energy comes from non-fossil fuels you don't have to burn carbon to build power plants.
> point out the impact of mining the fuel (and massive quantities of high-grade metals needed for the reactor and its supporting infrastructure) and people dismiss you with a waive of the hand.
Because it isn't massive quantities. One kg of uranium has the same energy content as two thousand metric tons of oil. A 1GW nuclear power plant generates as much power in a day as ~25,000 acres of solar panels.