> This number is based on existing mines (active and inactive) only. There's a lot more fissile material available than just the 40 Gg of usable fissile material. And that's assuming we only use U-235 and Pu-239.
That's all known and inferred accessible reserves. Not current mines. There are about 8-10 million tonnes of natural Uranium which has 0.5% extractable U235 (a bit more if you're willing to pay 10x as much for enrichment). There might be another big, high yield mine in Canada somewhere, but you probably want to check before putting down all our chips on it. U238 is not fissile.
> We also have viable LWR designs for Th-232 and are in the process of creating the first 5 Th-232 SMR test reactors at grid-scale right now.
So a technology that hasn't made it to the test bench, has no evidence as to its longevity or economics, probably requires more Beryllium than exists, and requires at least twice as much fissile material as is available for startup to breed fissile material from fertile thorium is your solution? One where the only proxy for how the extraction step might work is MOX reprocessed fuel which is more expensive than renewables on its own and releases more radiation under normal operation than Fukushima and TMI combined?
Why are you suggesting diverting funds from a technology that works to build a completely different technology from your solution that destroys precious fissile material it needs to scale quickly then? Even in the most optimistic scenarios it will take decades to breed up a fresh load of U233 to double your fleet, and you will have to throw away all your multi billion dollar PWRs.
Why not keep doing the thing that's provably working. That way if you solve the whole breeder thing then it will only take a few generations to breed enough fuel rather than hundreds.