In 75 years all of the low hanging fruit reserves will be mined out... according to current estimates that leaves 125 years of increasingly harder to get (i.e. more expensive) ore.
Then what? I guess develop the clean energy that we should be working on now.
No. Using proven fast reactor technology, we could supply 100% of the world's energy needs for 10,000 years just using the depleted uranium sitting unused in storage barrels at enrichment plants. Not to mention the huge amounts of raw uranium ore, tailings, reserves in localities that have previously banned mining, and seawater extraction. Nuclear fuel availability is purely a political and social problem, not technical.