Unless you also have a nuclear reactor to perform the high-temperature electrolysis process. https://en.wikipedia.org/wiki/High-temperature_electrolysis
Which only Japan seems to be working on building at the moment. https://www.hydrogeninsight.com/production/japan-plans-hydro...
It's cool tech, and I like that it's researched. But I think it's not a breakthrough that could realistically help the grid at the moment.