For the third time, the solution is to just save money by ditching the intermittent sources and only using nuclear. Nuclear makes renewables redundant, not the other way around. Nuclear generates power round the clock. Nuclear doesn't suffer from the duck curve, so it doesn't need storage or gas backup plants.

Nuclear does suffer from the duck curve. It has the opposite problem of what to do with the excess power when demand is lower.

No it does not. The Duck curve refers to the sinusoidal production of solar power (and wind power, to a lesser extent) https://en.wikipedia.org/wiki/Duck_curve. The duck curve refers to the problem of the fact that energy consumption is mostly flat, but solar solar produces a big curve from dawn to dusk. This is why renewables need so much storage, to take overproduction during peak hours and use that excess energy during the off-hours. Matching a flat source of energy generation to a mostly flat demand curve is much easier than adapting a sinusoidal source of energy generation to a flat demand.

The disparity between peak energy load and minimal energy load is only ~25%. Excess energy is an easy problem to solve. Nuclear power plants' thermal output is largely fixed, but their electrical output can be modulated by more aggressive cooling. Basically, deliberately produce more waste heat. If this nuclear plant is on the coast it can use this waste heat for desalination - the waste heat gives you freshwater as a bonus.

Another option is to not waste the heat, and use thermal storage. A well-insulated vat of salt is cheap, can be made arbitrarily large, and will hold heat over a 24 hour period with reasonable efficiency. So you store the heat during below-average demand and use it to generate extra electricity during above-average demand.

But the same solution also makes solar interesting again when it's used in combination, because you can store heat from nuclear during the times when solar is generating and then use it during the times when it isn't.

Sure, but thermal storage remains in the prototyping stage. Besides solar thermal generation I'm not aware of any grid scale thermal storage facilities. It's a potential future option, but it's not a presently extant option.

Thermal storage is based on basic physical principles. There is no question that it can be done. It hasn't been commercialized because the market for energy storage has heretofore been served by fossil fuels.

If you remove fossil fuels, you have to replace them with something. You're building new power plants. New nuclear power plants could straightforwardly be built with thermal storage.

Fusion is also based on basic physical principles. Do you think a plant to cut all funding for renewables or fission and putting it into fusion research amounts to a sound energy policy? Sound approaches to decarbonization are based on technologies that are currently available, not ones that might become available depending on the outcomes of research and development.

Nuclear plants definitely could use thermal storage, but the main advantage is of nuclear over renewables is that they have consistent energy production and thus don't need storage in the first place. It doesn't suffer from the duck curve like solar, or weather-dependent intermittency like wind. Nuclear doesn't need storage to become viable, as France has demonstrated for decades.

I stand corrected.

Typically you sell it or you reduce output (yes, you can reduce output).