It was found that Sc2@C84 or Sc2O3 could be “kicked” into the cavities of single wall carbon nanotubes (SWNTs) by reactor neutrons. Neutron irradiation also efficiently induces coalescing reactions between two fullerene cages with an atom-spacer, forming a C2m=C=C2n type of carbon nanomaterials. This process provides a new subject of studying interactions (and their consequences) of neutrons with nanoparticles, which may put new insights for neutron sciences.