NSUF 24-4883: Phase Field Modeling of Irradiation-Induced Crystallization in Amorphous Nuclear Oxides

The objective of this project is to understand the relative degree of irradiation-induced crystallization in amorphous metal oxides relevant to nuclear reactor environments. Many nuclear-relevant metal oxide ceramic are amorphous as-grown or as-fabricated. For example, the Zr oxide scale on cladding tubes, the Al-U oxide fuel-clad chemical interaction product between UO2 and FeCrAl cladding, and alumina glasses used for nuclear waste immobilization are all amorphous. In addition, amorphous UO2 is being studied owing to it unique properties compared to its crystalline form. However, our recent results have found that amorphous metal oxides can experience significant crystallization during irradiation. This phenomenon of irradiation-assisted crystallization typically occurs at temperatures several hundred degrees lower than the critical crystallization temperature, to phases not otherwise accessible through thermodynamics alone. Because the crystalline phase has higher atomic packing than the amorphous phase, internal stresses arise during irradiation-assisted crystallization, which could compromise structural integrity by resulting in bending, cracking, or flaking of the ceramic. To accurately predict the stability of amorphous oxides to ensure safe reactor operation or waste storage, there is a critical need to understand the extent and relative rates of irradiation-assisted crystallization in various amorphous metal oxides. We hypothesize that irradiation-assisted crystallization is highly dependent on irradiation energy and thermal conductivity of the target material. We will extend established phase field models of irradiation-assisted grain growth to irradiation-assisted crystallization by introducing a second phase. We will focus on three common nuclear oxides subject to irradiation: UO2, ZrO2, and Al2O3. Crystallization will be ascertained as a function of thermal conductivity, irradiation energy, and thermal spike probability. Results will be compared to experimental studies.

추가 정보

필드	값
Award Announced Date	2024-02-02T12:35:40.183
Awarded Institution	Purdue University
Facility Tech Lead	Alina Montrose
Irradiation Facility
PI	Md Ali Muntaha
PI Email	[email protected]
Project Type	RTE
RTE Number	None