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OAK B188 Isolation of Microstructure in Proton-Irradiated Steels. Topical Report. Component degradation by irradiation is a primary concern in both current reactor systems as well as advanced designs and concepts where the demand for higher efficiency and performance will be considerably greater. In advanced reactor systems, core components will be expected to operate under increasingly hostile (temperature, pressure, radiation flux, dose, etc.) conditions, The current strategy for assessing radiation effects for the development of new materials is impractical in that the costs and time required to conduct reactor irradiations are becoming increasingly prohibitive, and the facilities for conducting these irradiations are becoming increasingly scarce. The next generation reactor designs will require more extreme conditions (temperature, flux, fluence), yet the capability for conducting irradiations for materials development and assessment in the next 20 years is significantly weaker than over the past 20 years. Short of building new test reactors, what is needed now are advanced tools and capabilities for studying radiation damage in materials that can keep pace with design development requirements. The most successful of these irradiation tools has been high energy (several MeV) proton irradiation. Proton irradiation to several tens of dpa can be conducted in short amounts of time (weeks), with relatively inexpensive accelerators, and result in negligible residual radioactivity. All of these factors combine to provide a radiation damage assessment tool that reduces the time and cost to develop and assess reactor materials by factors of 10-100. What remains to be accomplished, is the application of this tool to specific materials problems and the extension of the technique to a wider range of problems in preparation for advanced reactor materials development and assessment. In this project, we plan to approach the mechanism of irradiation assisted stress corrosion cracking (IASCC) by isolating the irradiated microstructure. This report focuses on the microstructure of proton irradiated stainless steel and model alloys for reactor pressure vessel (RPV) steels. |
