[llsf]

Good questions. Just the first question is a rabbit hole on its own. How much nuclear fuel (lets focus on uranium) is left on Earth ? https://en.wikipedia.org/wiki/Peak_uranium Looks like there is uranium everywhere, including under your feet. There is more uranium than gold for instance. The question is about cost to extract. The more you spend the more you find. And the more you look and the more you find. "As of 2017, identified uranium reserves recoverable at US$130/kg were 6.14 million tons (compared to 5.72 million tons in 2015)".

Then on the other hand, it depends on how much uranium we use. "LWRs only consume about half of one percent of their uranium fuel while fast breeder reactors will consume closer to 99%. Currently, more than 80% of the World's reactors are Light Water Reactors (LWRs)."

So moving to fast breeder reactors would essentially live us with enough uranium for hundreds of years.