Measurement of neutron-irradiated microstructure using far-field high energy X-ray diffraction microscopy (FF-HEDM) in a high-temperature ultrafine-precipitate-strengthened (HT-UPS) austenitic stainless steel. Grain center of mass, grain size distribution, crystallographic orientation (texture), diffraction spot broadening and lattice constant distributions of individual grains were obtained for samples in three different conditions: non-irradiated, neutron-irradiated (3 dpa/ 500 deg C), and irradiated + annealed (3 dpa / 500 deg C + 600 deg C/ 1 h)