High grade waste, and there's plenty of that, from fission cores are stored on site and elsewhere. This stuff could be reprocessed for additional fissile material, but due to treaties and economics, it just sits.
There are private ventures underway to turn this high yield waste into thermal batteries/reactors to generate power. If these come to fruition, one report states there's 700 years or so worth of material waiting to be used.
You are a liar or badly misinformed. Yucca Mtn is designated to be the site of spent fuel rods.
https://en.wikipedia.org/wiki/Yucca_Mountain_nuclear_waste_repository