NSUF 22-4434: In situ TEM studies on thermodynamic stability and microstructural evolution of zirconium hydrides in irradiation and thermal environments
The authors propose the use of in situ TEM ion irradiation and annealing methods available in the Intermediate Voltage Electron Microscope (IVEM) facility at the Argonne National Laboratory (ANL) to investigate the real-time evolution of zirconium hydride (ZrH) when subjected to extreme conditions. This proposed investigation – focused on a fundamental level – are aimed at evaluating the microstructural changes within the δ- and ε-phases of zirconium hydrides from the point of view of both displacement (e.g. dislocation loops and voids) and impurity (e.g. inert gas bubbles) damage formation and evolution. In addition, the thermodynamic stability of different zirconium hydride phases will be assessed. On this latter topic, we aim at evaluating whether these phases will dissolve or amorphize both under annealing and irradiation. An innovative aspect of this present proposal is on the samples that will be used for the investigations. Two forms of zirconium hydrides will be investigated: (i) as precipitates within the microstructure of hydrogen-charged zircaloy-4 (Zr-1.5Sn in at. %) and as (ii) bulk materials as-processed via powder metallurgy or direct hydriding methods. The latter form is under active consideration to compose a novel class of materials to act as moderators in nuclear reactors, due to its inherent capability to store H from low to high atomic concentrations as light elements can help thermalize neutrons via scattering processes. The zirconium hydride materials have been synthesized at the Los Alamos National Laboratory (LANL) and TEM lamellae for in situ TEM ion irradiation will be prepared using conventional lift-out techniques within Focused Ion Beam (FIB) systems for the experiments at the IVEM. We plan to use a dual-beam setup consisting of a low-energy light inert gas, He at 6 keV to evaluate the nucleation and growth of bubbles, and a high-energy heavy inert gas, Kr at 1 MeV, to simulate a pure nuclear damage regime and a dense cascade of defects commonly generated in neutron-irradiation environments. To support the long-term, safe and reliable operation of nuclear reactors is of paramount importance to understand at a fundamental level using in situ TEM techniques, the dose and temperature ranges by which zirconium hydrides are (or not) stable within extreme environments. Phase transformations, development of displacement and impurity damage and alterations on the zirconium hydrides on a microstructural level could lead to failure of materials that can be predicted by the experiments herein proposed. This proposal intends to combine the capabilities found at the IVEM facility to efficiently map defect evolution as a function of gas concentration, damage dose, and temperature in all the potential of zirconium hydrides to be applied in the future in nuclear reactors.
Additional Info
| Field | Value |
|---|---|
| Abstract | The authors propose the use of in situ TEM ion irradiation and annealing methods available in the Intermediate Voltage Electron Microscope (IVEM) facility at the Argonne National Laboratory (ANL) to investigate the real-time evolution of zirconium hydride (ZrH) when subjected to extreme conditions. This proposed investigation – focused on a fundamental level – are aimed at evaluating the microstructural changes within the δ- and ε-phases of zirconium hydrides from the point of view of both displacement (e.g. dislocation loops and voids) and impurity (e.g. inert gas bubbles) damage formation and evolution. In addition, the thermodynamic stability of different zirconium hydride phases will be assessed. On this latter topic, we aim at evaluating whether these phases will dissolve or amorphize both under annealing and irradiation. An innovative aspect of this present proposal is on the samples that will be used for the investigations. Two forms of zirconium hydrides will be investigated: (i) as precipitates within the microstructure of hydrogen-charged zircaloy-4 (Zr-1.5Sn in at. %) and as (ii) bulk materials as-processed via powder metallurgy or direct hydriding methods. The latter form is under active consideration to compose a novel class of materials to act as moderators in nuclear reactors, due to its inherent capability to store H from low to high atomic concentrations as light elements can help thermalize neutrons via scattering processes. The zirconium hydride materials have been synthesized at the Los Alamos National Laboratory (LANL) and TEM lamellae for in situ TEM ion irradiation will be prepared using conventional lift-out techniques within Focused Ion Beam (FIB) systems for the experiments at the IVEM. We plan to use a dual-beam setup consisting of a low-energy light inert gas, He at 6 keV to evaluate the nucleation and growth of bubbles, and a high-energy heavy inert gas, Kr at 1 MeV, to simulate a pure nuclear damage regime and a dense cascade of defects commonly generated in neutron-irradiation environments. To support the long-term, safe and reliable operation of nuclear reactors is of paramount importance to understand at a fundamental level using in situ TEM techniques, the dose and temperature ranges by which zirconium hydrides are (or not) stable within extreme environments. Phase transformations, development of displacement and impurity damage and alterations on the zirconium hydrides on a microstructural level could lead to failure of materials that can be predicted by the experiments herein proposed. This proposal intends to combine the capabilities found at the IVEM facility to efficiently map defect evolution as a function of gas concentration, damage dose, and temperature in all the potential of zirconium hydrides to be applied in the future in nuclear reactors. |
| Award Announced Date | 2022-06-14T07:25:43.473 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Wei-Ying Chen |
| Irradiation Facility | None |
| PI | Caitlin Taylor |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 4434 |