An apparatus, system and method for storing high level radioactive waste. In one aspect, the invention is a specially designed ring-like structure for providing neutron and gamma radiation shielding for high level radioactive materials that produce residual heat. In one embodiment, the ring-like structure is designed to be stackable upon itself so as to form a stacked structure that completely surrounds an internal containment boundary. In another embodiment, the ring-like structure is designed to have voids with specially designed geometries for receiving neutron absorbing material. In another aspect, the invention is a spacer apparatus designed to be located within the containment boundary to support the fuel basket and/or to improve conductive heat removal through the containment boundary. In yet another aspect, the invention is a fuel basket comprising one or more flux traps that regulate production of neutron radiation and plates constructed of a metal matrix composite material.