The waste turns to U232, which you actually need a bit of to make a LFTR run.
Problem is that with Uranium reactors, if you put a cup of Uranium in one end, you get 3/4 cup of Plutonium out the other, so to speak.
It’s like saying “If I put a cup of silver in one side, I get 3/4 cup of gold out the other, plus I get power.”
The original financial analysis on Uranium reactors was that they literally paid for themselves in Plutonium yield. Plutonium is used to make Hydrogen bombs.