Nuclear fission is actually by definition the least renewable energy source

But if you go according the strict physical principle every energy source is non-renewable

The sun fuses a finire amount of hydrogen, earth has a finire amount of latent heat, the moon a finire amount of gravitational inertia etc.

And there’s a little paradox if you think about it, how can fusion be non-renewable but solar, that use radiation from the sun fusion, be renewable?