NSUF 18-1503: The study of local atomic structure and formation of ceramic phase in a simplified nuclear waste glassesl

This project aims to gain a fundamental insight into the stability of glass waste forms and glass-ceramic phases to be used for safe and reliable encapsulation of nuclear waste. In particular, we will seek to understand thermodynamic and structural properties involved in crystallization and phase separation in melt-derived waste forms, such as glasses and glass-ceramics, by using a baseline glass composition with varying additives. We will also study the effect of self-irradiation on the local atomic arrangement of a few selected glass compositions, and complement our approach by investigating the structural properties of amorphous and disordered ceramic phases. These research objectives will be addressed by synchrotron X-ray scattering experiments at the XPD beamline of NSLS-II. Pair distribution function (PDF) analysis will be applied to study the short-range and medium-range atomic arrangement within the glass and glass-ceramic materials, accompanied by characterization of the long-range structure of crystalline materials using XRD. Key to our approach will be the use of the unique in situ capabilities at the XPD beamline, which allows the investigation of the structure of materials as a function of increasing temperature up to 1500 °C. This will provide insight into what crystalline and glass phases will form with varying glass bulk composition, including changes in the short- and medium-range structure. All of these measurements can be completed with a 2-3 days beamtime. The obtained structural data will be afterwards analyzed by appropriate refinement techniques (PDF refinement and Rietveld refinement). Reverse Monte Carlo (RMC) modelling will be also used to gain further insight into the local atomic arrangement within the glass phase. Data analysis can be completed within 3 months after the beamtime. It is important to note that the outcome of this NSUF project will be directly used in a broader context within an ongoing NEUP project. The NEUP project aims to advance our knowledge and fundamental understanding of the thermodynamics of crystallization and phase separation in melt-derived nuclear waste forms. The same glass and glass-ceramics are used in this project to conduct combined neutron scattering and advanced calorimetric measurements, assisted by extensive modeling. The data obtained in this NSUF project will be complementary to the ones obtained in the NEUP project and provide important additional data for modelling which is beyond the scope of the NEUP project. Particularly the in situ high-temperature X-ray characterization proposed in this NSUF proposal is critical to better understand and interpret the high-temperature calorimetry data. High-temperature measurements are also possible with neutrons but are very challenging, lacking the detailed information (including kinetics) which are achievable by X-ray characterization.

추가 정보

필드	값
Abstract	This project aims to gain a fundamental insight into the stability of glass waste forms and glass-ceramic phases to be used for safe and reliable encapsulation of nuclear waste. In particular, we will seek to understand thermodynamic and structural properties involved in crystallization and phase separation in melt-derived waste forms, such as glasses and glass-ceramics, by using a baseline glass composition with varying additives. We will also study the effect of self-irradiation on the local atomic arrangement of a few selected glass compositions, and complement our approach by investigating the structural properties of amorphous and disordered ceramic phases. These research objectives will be addressed by synchrotron X-ray scattering experiments at the XPD beamline of NSLS-II. Pair distribution function (PDF) analysis will be applied to study the short-range and medium-range atomic arrangement within the glass and glass-ceramic materials, accompanied by characterization of the long-range structure of crystalline materials using XRD. Key to our approach will be the use of the unique in situ capabilities at the XPD beamline, which allows the investigation of the structure of materials as a function of increasing temperature up to 1500 °C. This will provide insight into what crystalline and glass phases will form with varying glass bulk composition, including changes in the short- and medium-range structure. All of these measurements can be completed with a 2-3 days beamtime. The obtained structural data will be afterwards analyzed by appropriate refinement techniques (PDF refinement and Rietveld refinement). Reverse Monte Carlo (RMC) modelling will be also used to gain further insight into the local atomic arrangement within the glass phase. Data analysis can be completed within 3 months after the beamtime. It is important to note that the outcome of this NSUF project will be directly used in a broader context within an ongoing NEUP project. The NEUP project aims to advance our knowledge and fundamental understanding of the thermodynamics of crystallization and phase separation in melt-derived nuclear waste forms. The same glass and glass-ceramics are used in this project to conduct combined neutron scattering and advanced calorimetric measurements, assisted by extensive modeling. The data obtained in this NSUF project will be complementary to the ones obtained in the NEUP project and provide important additional data for modelling which is beyond the scope of the NEUP project. Particularly the in situ high-temperature X-ray characterization proposed in this NSUF proposal is critical to better understand and interpret the high-temperature calorimetry data. High-temperature measurements are also possible with neutrons but are very challenging, lacking the detailed information (including kinetics) which are achievable by X-ray characterization.
Award Announced Date	2018-05-17T11:23:58.19
Awarded Institution	None
Facility	None
Facility Tech Lead	Simerjeet Gill
Irradiation Facility	None
PI	Maik Lang
PI Email	[email protected]
Project Type	RTE
RTE Number	1503