Thorium is kind of like diesel, it doesn't work well in a spark ignition engine. Thorium doesn't work very well in a solid fuel reactor. Liquid Fluoride Thori

Thorium is kind of like diesel, it doesn't work well in a spark ignition engine. Thorium doesn't work very well in a solid fuel reactor. Liquid Fluoride Thorium Reactors (LFTRs, pronounced "lifters") on the other hand work very nicely. All the "reasons" you mention apply to solid fuel reactors, not LFTRs. The man who invented both preferred the LFTR.