An Atomic-Scale Characterisation Facility for Active Nuclear Materials

点击翻译按钮获取中文摘要

The design, build and maintenance of next generation fission and fusion reactors must be underpinned by research into how materials for their construction will degrade when exposed to the harsh reactor environment. This deterioration is largely driven by the extensive bombardment of high energy neutrons, which both damage the structure of the materials, and ultimately over extended periods can transform it, changing its properties. This process is initiated at the atomic level. Hence a better understanding of how the microstructure evolves, from this scale, under the combination of extreme temperature and irradiation conditions within the reactor, and correlating this to the deterioration of mechanical properties, is essential to predict safe operating lifetimes of critical components.This proposal is to establish a state-of-the-art Active Atom Probe Facility as a national user facility for UK researchers. Atom probe tomography (APT) is a type of microscopy that provides unique insight into 3D atomic distributions within materials at a scale that even the most advanced electron microscopes cannot routinely achieve. APT can be used to identify and characterise the very onset of irradiation-induced damage in nuclear materials. It is now an indispensable materials characterisation tool utilised in a wide variety of research and development into nuclear materials. APT is a destructive characterisation technique, meaning that when active specimens are analysed, during the experiment sample material will be deposited within the instrument. In the case of active materials, this represents serious logistical and safety concerns for the maintenance and operation of the instrument. Hence, for UK researchers to undertake such analyses routinely, effectively and safely requires the establishment of an APT facility dedicated to the characterisation of radioactive materials. The Active Atom Probe Facility represents a collaboration between the University of Oxford and the UKAEA's Materials Research Facility (MRF) to maximise the effectiveness of UK expertise and infrastructure. While the atom probe instrumentation will be installed at Oxford, prior to analysis APT specimens must be prepared from larger, significantly more radioactive samples. This will be undertaken utilising a Focused Ion Beam instrument to be installed at the MRF, which has the experience and facilities for safe handling, preparation and examination of irradiated reactor materials. This Active Atom Probe Facility will provide fully-supported access and training to scientists from UK academia and industry across every step of the APT experiment, from specimen preparation through to data analysis and interpretation of the results. Users of the new instruments will be trained to an expert level in all aspects of the technique, with an emphasis on all specific precautions required to undertake experiments radioactive materials. It will therefore play a key role in the development of the next generation of UK scientists who will contribute to re-establishing international leadership in nuclear materials research. Access to this unique capability will support research across a range of different stages in the fission and fusion nuclear energy cycle, including: design and manufacture of new irradiation resistant materials for next generation reactors, contributions to safety critical reactor monitoring, validating ion/proton irradiation as a neutron surrogate, developing effective, long-lasting waste storage solutions and steering research for future fusion plants.