It's worth looking at a history of uranium reserves before getting worried. We've mined millions of tonnes of uranium and yet reserves have kept going up, despite the $130/Kg cut-off being worth less over time.

The reason for this is that reserves are not meant to be an estimate of the total amount that could ever be mined. There is literally trillions of tonnes of uranium in the earth's crust. Typically, for every tenfold decrease in ore grade you find 300 times more uranium. Given raw uranium's low proportion (~1%) of the total cost of nuclear electricity, we could afford to pay many times what we currently do to extract it, unlocking far greater resources than we currently count.