Aerodynamic levitator for in situ x-ray structure measurements on high temperature and molten nuclear fuel materials

Abstract

An aerodynamic levitator with carbon dioxide laser beam heating was integrated with a hermetically sealed controlled atmosphere chamber and sample handling mechanism. The system enabled containment of radioactive samples and control of the process atmosphere chemistry. The chamber was typically operated at a pressure of approximately 0.9 bars to ensure containment of the materials being processed. Samples 2.5-3 mm in diameter were levitated in flowing gas to achieve containerless conditions. Levitated samples were heated to temperatures of up to 3500 °C with a partially focused carbon dioxide laser beam. Sample temperature was measured using an optical pyrometer. The sample environment was integrated with a high energy (100 keV) x-ray synchrotron beamline to enable in situ structure measurements to be made on levitated samples as they were heated, melted, and supercooled. The system was controlled from outside the x-ray beamline hutch by using a LabVIEW program. Measurements have been made on hot solid and molten uranium dioxide and binary uranium dioxide-zirconium dioxide compositions.

Rare‐earth titanate melt structure and glass formation

“…In a typical experiment, a ∼2 mm diameter bead of sample material is levitated on a gas stream flowing through a converging‐diverging conical nozzle. A 400 W, 10.6 μm, CO 2 laser impinges onto the top of the sample from above, and sample temperature is measured by optical pyrometry in the infrared region …”

Investigation of Structure and Dynamics in Disordered Materials Using Containerless Techniques with In-Situ Quantum Beam and Thermophysical Property Measurements

“…We can probe the bulk structure of a 2-3 millimeter diameter liquid droplet. (iii) High-flux X-rays are suitable for time-resolved diffraction experiments when combined with an area detector [4].…”

Determining the Structure of Stable and Supercooled Liquids by High Energy X-Ray Diffraction

“…In a typical HEXRD experiment a transmission geometry is adopted [2]. The incident X-ray beam is collimated to a size of, routinely 0.5 x 0.5 mm and scattered X-rays detected on a vertically mounted, 2048 x 2048 flat plate scintillation detector.…”

“…In addition, the intensity of the scattered radiation from an amorphous or liquid sample is significantly lower than that from crystalline samples. Despite these apparent drawbacks liquid state diffraction techniques have been developed and applied to a range of materials over a range of temperatures [2]. In this contribution we will highlight some recent studies that involve high energy X-rays, combining these with containerless techniques, and will outline possible future direction for these types of studies.…”