NSUF 13-395: Atom Probe Tomography to Study Helium Segregation and Bubble Formation in Uranium Dioxide

Irradiation of oxide fuels, specifically UO2 leads to the formation of insoluble fission products, such as helium (He) changing the path phonons travel, reducing its thermal transport behavior. The addition of insoluble fission products, which tend to cluster intragranularly with increasing irradiation dose, swell the fuel, degrading its overall fuel performance. Of interest in this proposed research is to investigate the evolution and segregation of He in UO2 with Atom Probe Tomography (APT). APT is uniquely suited due to its nanometer scale spatial resolution and chemical identification abilities to 3-dimensionally investigate the growth characteristics of the He clusters and its chemical composition. Additionally of interest in this proposal is to investigate the changes in UO2 near clusters. In order to characterize the precise chemical and spatial distributions of the He bubbles in UO2, laser-assisted atom probe tomography (APT) in conjunction with the focused ion beam (FIB) system available at CAES will be used. The FIB system will be used to prepare site-specific samples that target regions inside the grains and near grain boundaries to fabricate atom probe tips. Each sample analyzed will be reconstructed using the IVAS software (available both at CAES and PI Manuel’s laboratory at the University of Florida) to study He bubble evolution and segregation in UO2. Samples will be studied in the late Fall or Winter 2012. Final results will then be published in peer- reviewed journal articles and presented at fuels-related conferences. It is expected that these results will provide new insight into the spatial and chemical distribution fission product clusters in UO2, allowing for the correlation with atomic-level simulations and/or the ability to link with mesoscale structure-property relationships.

Допълнителна информация

Поле	Стойност
Abstract	Irradiation of oxide fuels, specifically UO2 leads to the formation of insoluble fission products, such as helium (He) changing the path phonons travel, reducing its thermal transport behavior. The addition of insoluble fission products, which tend to cluster intragranularly with increasing irradiation dose, swell the fuel, degrading its overall fuel performance. Of interest in this proposed research is to investigate the evolution and segregation of He in UO2 with Atom Probe Tomography (APT). APT is uniquely suited due to its nanometer scale spatial resolution and chemical identification abilities to 3-dimensionally investigate the growth characteristics of the He clusters and its chemical composition. Additionally of interest in this proposal is to investigate the changes in UO2 near clusters. In order to characterize the precise chemical and spatial distributions of the He bubbles in UO2, laser-assisted atom probe tomography (APT) in conjunction with the focused ion beam (FIB) system available at CAES will be used. The FIB system will be used to prepare site-specific samples that target regions inside the grains and near grain boundaries to fabricate atom probe tips. Each sample analyzed will be reconstructed using the IVAS software (available both at CAES and PI Manuel’s laboratory at the University of Florida) to study He bubble evolution and segregation in UO2. Samples will be studied in the late Fall or Winter 2012. Final results will then be published in peer- reviewed journal articles and presented at fuels-related conferences. It is expected that these results will provide new insight into the spatial and chemical distribution fission product clusters in UO2, allowing for the correlation with atomic-level simulations and/or the ability to link with mesoscale structure-property relationships.
Award Announced Date	2012-12-20T00:00:00
Awarded Institution	None
Facility	None
Facility Tech Lead	Yaqiao Wu
Irradiation Facility	None
PI	Michele Manuel
PI Email	[email protected]
Project Type	RTE
RTE Number	395