The Earth's crust will take far longer to move yucca than the nuclear waste will be a problem. That's the whole reason that site was chosen. Even Yellowstone isn't set to blow on that time scale.

Why dont you suggest what "safe" looks like, and we can discuss your understanding of safety. Its clear to me that the issue is your standards and not actual waste disposal.

The movement of tectonic plates is something that takes millions, not thousands, of years. Not to mention Yucca Mountain is far from the edge of any tectonic plate.