We already have (or had) a working prototype thorium reactor.
It ran very well and was very safe. You could turn it off on the weekends
and crank it right back up on Monday morning..
I guess the big corporations who make fuel rods for light-water reactors
had no interest in thorium fueled reactors, since they were so cheap to run.
No profit in them.
Instead of spending a few of billion on building some new prototypes,
we are going to use the money to bail out Fanny & Mac again..