b'An innovative approachThe boron neutron capture method expedites new nuclear for accelerated irradiationmaterial qualification and computational model validation studies of materials by changing the paradigm for irradiation studies.T his project developed a boron neutron capture method to accelerate the irradiation damage in low-flux research reactors. Ion irradiation has been used as a surrogate for neutron irradiation to accelerate irradiation damage in materials. However, ion irradiation creates a number of features in materials that are not observed in neutron irradiated specimens and lead to atypical irradiation damage. In this project, we developed an in-pile boron neutron capture method to PROJECT NUMBER:accelerate irradiation damage studies of materials in research reactors. Boron-10 21A1050-099FPabsorbs thermal neutrons and leads to nuclear capture. This fission reaction yields PRINCIPAL INVESTIGATOR:high-energy alpha particles and creates high flux irradiation damage. Unlike the ion Mukesh Bachhav irradiation-induced anisotropic irradiation damage, this approach provides isotropic irradiation environments with neutrons and alpha particles, which dramatically CO-INVESTIGATORS: accelerates in-pile irradiation flux. We irradiated titanium aluminum-based alloys Chao Jiang, INLwith boron addition and iron boride intermetallics in low-flux 300 kilowatts Cheng Sun, INL Training Research Isotope General Atomics reactor and the Massachusetts Institute Ju Li, Massachusetts Instituteof Technology Reactor. Irradiation-induced microstructural and chemical evolution of Technologywere characterized using scanning transmission electron microscopy. The accelerated irradiation damage led to the chemical intermixing in titanium aluminum alloys and defect clustering in iron boride intermetallics that typically occurs at high neutron fluences. This approach increases the irradiation flux in research reactors and significantly decreases the time required for irradiation studies of materials. The approach developed in this project supports the rapid discovery and qualification of new materials for reactor applications. Scanning transmission electron microscopy images showing the chemical distribution of titanium aluminum tungsten boron (Ti-Al-W-B) alloy. (left) Before irradiation. Ti-Al alloys showing two-phase nano-lamellar structure with molybdenum (Mo) segregated in thephase. (right) After neutron irradiation. Irradiation-induced intermixing occurs at such low dose irradiation due to the accelerated irradiation flux caused by boron addition. Mo is uniformly distributed in bothandphases after irradiation.40'