"Since the neutron flux in the reactor is the main variable which controls the power output it seems, that a Thorium reactor is significantly harder to control

"Since the neutron flux in the reactor is the main variable which controls the power output it seems, that a Thorium reactor is significantly harder to control than a Uranium one." This is nonsense. LFTRs are self controlling with a significant negative coefficient. It really makes no more sense to think about putting Thorium in a solid fuel reactor than it does about using diesel in a spark ignition engine.