Atomic-scale spectroscopy of uranium oxide published in PNAS
Our paper, detailing what we believe may be the first atomic-resolution electron energy loss spectroscopy (EELS) measurements of any actinide, has just been published in the Proceedings of the National Academy of Science (PNAS). The article, titled “Nanoscale oxygen defect gradients in UO2+x surfaces,” describes the oxidative behavior of UO2 surfaces. In contrast to prior reports, our EELS measurements, interpreted in light of first principles calculations and image simulations, indicate that a substantial amount of interstitial oxygen can be incorporated into the surface without a phase transformation. This new approach will open a window to examining oxidative behavior in the actinides at high spatial resolution.
From the abstract:
Our study has far-reaching implications for the safe use of nuclear materials around the world. The strong oxidative tendency of the actinides drives contamination of groundwater near waste storage sites. A key finding of our study is that excess oxygen from the environment can be incorporated at far greater levels than previously thought, while still preserving the nominal cubic crystal structure of the widely used nuclear fuel UO2UO2. This insight, enabled by atomic-resolution spectroscopy and theory calculations, will allow us to develop better, more reliable models for nuclear waste storage and disposal.