Thoroum gets converted to U233 in the reactor. It's esentially a breeder reactor. It helps with non proliferation somewhat because U232 is also a side product o

Thoroum gets converted to U233 in the reactor. It's esentially a breeder reactor. It helps with non proliferation somewhat because U232 is also a side product of the Thorium cycle and it's highly gamma radioactive, preventing tampering with the fuel. Which also makes it more dangerous in case of leaks and environment contamination, because it would kill anything around it and also fry electronic circuits, thus preventing cleanup with robots.