Storage would be considerably less complicated due to the properties of thorium.  Th-232 captures a neutron and (through two beta decays) becomes U-233.  It takes another FOUR neutron captures to turn U-233 into U-237, which can decay into neptunium; another neutron capture is required to create Np-238 which decays to plutonium.  To get there, all the intermediates have to avoid being fissioned by any of the neutrons.  The consequence is that the spent fuel of a thorium reactor would have only minuscule amounts of plutonium.