TRISO

Tri-structural isotropic (TRISO) fuel is a form of micro-particle nuclear fuel. Each particle consists of a kernel of uranium dioxide (UO2) fuel (sometimes UC or UCO), which has been coated with four layers of three isotropic materials deposited through fluidized-bed chemical vapor deposition. TRISO fuel particles are designed not to crack from thermal or mechanical stresses at temperatures up to 1600 °C, and therefore can contain the radioactive fission products even during severe accidents.