The level and extent of solute segregation to individual dislocations and interfaces may be visualized and quantified by atom probe tomography. The large volume of analysis and high data acquisition rate of the local electrode atom probe (LEAP (R)) enables the solute distribution in the region of and along the core of dislocations to be estimated. Solute segregation at precipitate-matrix interfaces of precipitates as small as 2-nm diameter may be quantified. Examples are presented of solute segregation to dislocations and clustering/precipitation in a neutron irradiated Fe-Ni-P model alloy and the neutron irradiated beltline weld from the Midland reactor.