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.