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If you can't change the physics, you can change the economics by passing a carbon tax (although I don't know if the carbon cost of building a nuclear plant would make it cost-savings positive).

Yeah. It really is complicated.

That's the thing with nuclear, if we really want it, at some point, the government is going to have to kick in some money to do it. With all of the competing generation technologies looking so good as investments right now, it really would almost be financial malfeasance for an investment group to put money into nuclear instead. You have to give those guys something if you want to make it happen. Right now, even with no subsidies, it's just hard to compete with a lot of these other investment opportunities in power generation.

And even government subsidies are going to be complicated, because I'm sure the tax payers would get up in arms about having to finance private reactors. Especially when more and more of them could be getting their energy from wind, natural gas, and hydro or pumped hydro. At that point you'd have people in, say, Iowa, where wind is abundant, paying for reactors for people in New York, or Florida.

I suspect that would likely go over about as well as a fart in church.

There has been a federal production tax credit available for new nuclear power in the US since 2005:

https://www.nei.org/advocacy/build-new-reactors/nuclear-prod...

It's structured similarly to the wind power production tax credit but isn't as generous. Presumably this is because in 2005 lawmakers believed that nuclear power was a more mature, more affordable electricity source than wind and needed less subsidy to attract new investment.

I'd be fine with nuclear incentives matching PTC terms for wind power (available for 10 years after construction instead of 8, same per-unit rate, no cap on nationwide capacity). But I don't think even that would be enough to spur new investment. Both wind and nuclear power projects have costs concentrated up-front in construction, but wind projects can go much smaller in terms of capacity and dollar investment. $75 million wind projects are common. Any modern power reactor is a multi-billion dollar commitment at minimum, and there's a longer time lag between pouring first concrete and selling the first watt of power. These long timelines and "chunky" capital requirements made investors wary, even before South Carolina and Georgia demonstrated that the newest reactor projects still have major problems sticking to planned cost and schedule.

That is how I thought.

Back in 2000 I was a leader in the local Green Party and my ultimate "stretch goal" was to shut down the coal burning power plant that was a single point source of CO2 greater than everything else in the county.

It did not look at all practical to do it, we did other things, then the group broke up.

A decade later the coal burning power plant got put out of business by hydrofracking. (The town the power plant was in was furious that it was losing the tax revenue, which was one of the reasons I knew getting rid of the plant was a non-starter.)

(Oddly enough after the Green Party in our county wound up in 2003, the big environmental activism in our area was "stop fracking".)

What did I learn from that? Better technology and market forces can accomplish things that politics can't.

It is common to frame the climate change problem as being caused by "entrenched fossil fuel interests" and that is certainly part of it, but most people are at least somewhat aware that the lifestyle they lead was not possible at all in the "solar economy."

Surveys show that climate change is a lower priority globally than "good jobs", "clean government", "access to health care" and if we see tackling climate change as a zero sum game about those things then tackling climate change will damage the legitimacy of governments and make people feel less represented and contribute to political instability.

The technical fix on the other hand lets governments focus on what their constituents want.

Can someone ELI5 why a nuclear reactor only operates at a lower temperature? I'm also surprised that it doesn't drive a generator via a turbine. I would assume the reactor speed and temperature can be arbitrarily tuned from zero to meltdown via the control rod. Is the hot-enough/economical range not being used risk management or some physical constraint?

Canada also seems to be pushing for smaller <100MW modular reactors. Would those change the equation?

The type of reactor that is common today is the Light Water Reactor (LWR)

The temperature is determined by practical considerations, particularly the coolant that is in use. The LWR is limited by the use of water as a coolant, but it doesn't attain temperatures as high as a coal burning power plant does because of materials considerations. The reactor has to hold up for a long time under a high radiation field and the results of a failing reactor vessel would total the reactor and lead to an expensive clean-up. (But wouldn't be an environmental catastrophe so long as water could be kept circulating in the confinement)

To raise the operating temperature we would need to switch to a different coolant, and that is easier said than done because that coolant has to be compatible with all the materials in use, not absorb too much radiation, not be damaged by the radiation, not be made radioactive than the radiation, etc. The physical form of the fuel is affected by this too.

For instance, LWR fuel can be removed from the reactor and stored under water for 15-20 years and then stored in dry casks for an indefinite time. We know we could bury it underground and it would stay there for thousands of years. We know how to dissolve it in nitric acid, extract the uranium and plutonium and use it to make new fuel.

The waste management story is much sketchier with alternative fuel forms.

People have built reactors with different coolants, a good selection can be found here:

https://en.wikipedia.org/wiki/Generation_IV_reactor

As for the "small modular reactor" that is going from the frying pan to the fire. The first LWRs that we built were small and it was clear that the economic case for them was bad and it was thought that it could be improved by "going big" but that didn't happen.

I'm not a proponent of earth based nuclear because of the storage issue, however if we're going to force the issue we at least need something better than LWR which was effectively chosen because it was the right choice for submarines. Sodium reactors at least avoid the Chernobyl meltdown situation. I'd never heard of the making new fuel with nitric acid, that's at least an interesting, if probably not commercially viable solution.

Supercritical CO2 turbines can be tiny. (They can also be used to recover the energy from the waste heat of internal combustion turbines).