Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12 Page 13 Page 14 Page 15 Page 16 Page 17 Page 18 Page 19 Page 20 Page 21 Page 22 Page 23 Page 24 Page 25 Page 26 Page 27 Page 28 Page 29 Page 30 Page 31 Page 32 Page 33 Page 34 Page 35 Page 36 Page 37 Page 38 Page 39 Page 40 Page 41 Page 42 Page 43 Page 44 Page 45 Page 46 Page 47 Page 48 Page 49 Page 50 Page 51 Page 52 Page 53 Page 54 Page 55 Page 56 Page 57 Page 58 Page 59 Page 60 Page 61 Page 62 Page 63 Page 64 Page 65 Page 66 Page 67 Page 68 Page 69 Page 70 Page 71 Page 72 Page 73 Page 74 Page 75 Page 76 Page 77 Page 78 Page 79 Page 80 Page 81 Page 82 Page 83 Page 84 Page 85 Page 86 Page 87 Page 88 Page 89 Page 90 Page 91 Page 92 Page 93 Page 94 Page 95 Page 96 Page 97 Page 98 Page 99 Page 100 Page 101 Page 102 Page 103 Page 104 Page 105 Page 106 Page 107 Page 108 Page 109 Page 110 Page 111 Page 112 Page 113 Page 114 Page 115 Page 116 Page 117 Page 118 Page 119 Page 120 Page 121 Page 122 Page 123 Page 124Nuclear Science User Facilities 94 from the AdvancedTest Reactor sample library, conducted through the University of Wisconsin ATR Pilot Program.The team then conducted charged particle irradiations using 2.0-MeV protons or 5.0‑MeV Fe++ ions at the Michigan Ion Beam Laboratory, through an NSUF rapid turnaround irradiation experiment.A follow‑on rapid turnaround experi- ment enabled the team to complete a comprehensive microstructure charac- terization of all irradiated specimens using a combination of transmission electron microscopy (TEM) and local electrode atom probe (LEAP).All post-irradiation materials character- ization work was conducted in the Microscopy and Characterization Suite (MaCS) at the Center for Advanced Energy Studies (CAES), utilizing the FEI Quanta focused ion beam (FIB), CAMECA 4000X HR LEAP, and FEI Tecnai S-TwinTEM. TEM results show that grain size, dislocation line density, and carbide precipitates remain unchanged upon self‑ion, proton, and neutron irradia- tion. Irradiation-induced dislocation loops and voids were also observed by TEM in all three irradiated samples. Notably, dislocation loop size and number densities were consistent across all irradiations (Figure 1). Only a few voids were observed, and they had diameters ~5 nm and were sparsely populated.These results suggest that atTEM resolutions, the neutron-irradiated microstructure in Fe-9%Cr ODS can generally be repli- cated using either self-ion or proton irradiation carried out at identical doses and temperature. To complement our TEM analysis, LEAP enabled atomic-level resolu- tion characterization of the oxide nanoclusters prior to and after each irradiation. Self‑ion and proton irradiation led to decreases in the average nanocluster size by ~0.9- 1.2 nm. However, neutron irradiation induced a more significant decrease in nanocluster size by more than 2.5 nm.The evolution of the particle size distributions (Figure 2) and number density of the nanoclusters after all irradiations suggest partial dissolution of the nanoclusters, but the extent of dissolution varies by irradiating particle.These results suggest that charged particle irra- diations can produce comparable micro-scale features (e.g., dislocation loops and voids) as neutron irradia- tion, without a temperature or dose shift. However, at the nanoscale, the irradiating particle and/or irradia- tion dose rate has a greater effect, as charged particles are unable to produce consistent nanoscale features as neutron irradiation. To correlate microstructure and nanostructure with macroscopic properties, the team conducted nanoindentation to evaluate the irradiation hardening of the neutron and charged particle irradiated samples.The nanohardness was