It’s a little bit complicated and I don’t want to write a wall of text but: Waste fuel can be recycled, if your reactor has a breeding ratio higher than 1 then it has net positive production of fissile materials. Potentially all uranium and thorium of the planet could be used.
The argument being, if you consider the word “renewable” in the strictest sense, no energy source is renewable, entropy can only increases: solar depends by the sun burning a finire amount of hydrogen, geothermy depends by earth inner heat which is a finire amount ecc.ecc. The common usage of renewable is along the line of “immensely big proportional to human consumption” and in this sense there’s a strong argument to consider nuclear renewable.