2018 | AFC ACCOMPLISHMENTS 147 There are many candidate materials in existence, and a thorough evaluation of the effectiveness of ion irradiations requires performing comparative studies on a wide range of candidate materials.The results presented here on just one alloy (MA957) are thus understood to be a step in a larger, ongoing effort.The neutron irradiations were conducted in the DOE-NE owned Fast Flux Test Facility (FFTF) in the late 1980's while the ion irradiations were conducted using Cr ions at the Kharkov Institute of Physics and Technology (KIPT) in the Ukraine. Irradiation temperature and dose were similar between the two irradiation methods. Many qualitative similarities in the microstructure of neutron and ion irradiated MA957 were observed after moderate amounts of irradiation exposure. Some examples are 1) radiation induced alpha-prime precipitate formation occurred over the same irradiation temperature range, 2) low amounts of void swelling were observed, and 3) there was good stability of the oxide particle population that is present in this material. However perhaps not surprisingly, quantitative assessment of the microstructure revealed some differences. For instance the alpha-prime population in the ion irradiated material had a different size and number density than in the neutron irradiated material as shown in Figure 1. Comparative studies just getting started on other materials are showing similar results with many qualitative similarities but quantitative differences. The outlook thus far is that optimized ion irradiation techniques are showing promise as a first line screening tool that will provide insight into the neutron irradiation response of a material, perhaps with the ability to allow weeding out materials with clear performance issues. Efforts to fully understand the value will continue for the next several years. Figure 1. Mean size (radius) and number density of alpha-prime precipitates as a function of irradiation temperature for MA957 irradiated by neutrons or ions.