RADIATION EFFECTS IN NUCLEAR FUELS

Abstract

Nuclear fuels have to operate reliably for years under extreme conditions of radiation damage. The main physical process for heat production, used to generate electricity, is to slow down and stop the highenergy heavy ions, i.e., the fission products (FPs). When an actinide atom is fissioned, about 200-MeV energy is dissipated in the fuel lattice. Most of this high energy is carried by the FP that cover the mass range from A = 75 to 160, hence elements between Ga and Dy. The FPs fall into two groups: the light ones, typically Kr, with about 100 MeV energy, and the heavy ones, typically Ba, with about 70-MeV energy. Intense neutron fluxes with energies ranging from eV to MeV interact with the fuel atoms, and there is an intense {\$}\beta{\$}.{\$}\gamma{\$}-radiation field because most FPs are radioactive with different decay energies and very different half-lives.