We can mass-produce metal/carbon nanotube (CNT) composites that show improved radiation tolerance. The 0.5wt% Al+CNT composite showed improved tensile strength without reduction of tensile ductility before radiation, and reduced void/pore generation and radiation embrittlement at high displacements per atom (DPA). Under helium ion irradiation up to 72DPA, the 1D carbon nanostructures survive, while sp2 bonded graphene transforms to sp3 tetrahedral amorphous carbon. Self-ion (Al) irradiation converts CNTs to a metastable form of Al4C3, but still as slender 1D nanorods with prolific internal interfaces that catalyze recombination of radiation defects, reducing radiation hardening and porosity generation. The 1D fillers may also form percolating paths of “nano-chimneys” that outgas the accumulated helium and other fission gases, providing an essential solution to the gas accumulation problem.