(HfNbZrTaW)C₅ high entropy carbide ceramics by spark plasma sintering for shielding materials of spent fuels

For the transportation and storage of spent fuels, where significant levels of neutron and gamma radiation are encountered, shielding materials are essential. In this paper, a new type of (HfNbZrTaW)C₅ high-entropy carbide ceramics with face-centered cubic rock-salt structure was designed and prepared as an integrated shielding material for both neutron and gamma ray protection, intended to replace the existing lead and epoxy resin. A single-phase (HfNbZrTaW)C₅ pellet with the best oxidation resistance was synthesized at 1700 °C by spark plasma sintering (SPS), achieving a theoretical density of 98.51 % and a hardness value of 25.28 GPa. Incorporating 10 wt % ZrB₂ into (HfNbZrTaW)C₅ ceramic sintered at 1700 °C can significantly enhance its the neutron absorption capacity, thermal conductivity, and oxidation resistance, positioning it as a potential integrated shielding material for spent nuclear fuels.