2018 | ANNUAL REPORT 97 In general, three types of nitrides were identified in HT9 andT91, including VN, Z phase, and Cr2N. In addition to the model and F/M alloys, PIE work on an irradiated Fe–14Cr-base ferritic oxide disper- sion strengthened (ODS) alloy MA957 has also started. Currently, microstructure characterization has been completed. Few dislocation loops were found in the lowest-dose specimens, and large loops were only found in the highest-dose specimens. The loops found in the intermediate dose (1.02 dpa at 340°C and 0.69 dpa at 478°C) were small black-dots. It might be possible to divide the loop evolution into two regimes: loop nucleation below ~1 dpa, and loop growth above ~1 dpa. Since MA957 is a Fe–14Cr alloy, the Cr content is above the threshold value for α' precipitation, which can be accelerated by neutron irradiation. Indeed, α' precipitation was observed in irradiated MA957 at several irradia- tion conditions.The α' precipitates can be readily seen from the Cr atom maps at the highest dose. More detailed analysis using Cr isosurfaces show that some α' precipitates can also be found in the ~1 dpa specimens. In Situ tensile tests with Figure 10. G-phase and Cu- rich phase coexist in irradiated HT9 and T91 over the medium temperature range.