Structural modifications in aged PuO2

This study aims at understanding radiation induced modifications in fluorite derived oxides that mimic the morphology, crystallography, phase stability similar to PuO₂ and aged PuO₂

Large stockpiles of PuO₂ are a continuously changing system due to transmutation that leads to changes in the chemistry and concomitant accumulation of radiation induced damage. These over long periods of time will change the morphology, thermal and mechanical properties of large inventories of aged PuO₂ [1] Experimental characterisation and understanding these modifications are crucial for safeguarding and providing a scientific basis for reuse of PuO₂ in future advanced nuclear fuel cycle. While significant effort is being made to develop computational models to predict long-term effects of transmutation and radiation on aged PuO₂, these models will rely on accurate crystallographic description of phases formed from long-term aging of PuO₂ and measurement of thermal properties using specimens of aged PuO₂ that have been undergoing this aging process for a significantly long time. Due to unavailability of aged PuO₂ and facilities that can handle alpha-active materials, understanding crystallography and phase equilibria of mixed oxides of PuO₂ requires the use of non-radioactive surrogates like mixed oxides of CeO₂ UO₂ ThO₂ and radiation damage using accelerated ion beams [2,3].Transmutation of PuO₂ results in creating a heavy energetic daughter nucleus and an alpha-particle. These energetic species will lead to self-irradiation of nano grained PuO₂ thus producing atomic level disorder and accumulation of He in an otherwise ordered compound. PhD work will kinetics of He release and how this accumulation of He is synergistically complemented by displacive damage caused by the heavy recoil atom to produce an aged microstructure in nano grained powders that mimic PuO₂ in its crystallographic phase and morphology (Re₂O₃:CeO₂ and Re₂O₃:UO₂). The work will explore phase stability and radiation effects in nano-powders using accelerated ions and post irradiation characterisation will be performed using Raman spectroscopy, X-ray diffraction (XRD) and Transmission electron microscopy (TEM). To compare phase stability and radiation effects in surrogates, PuO₂ will be characterised from different lines using NNUF facilities and hand-in-pocket approach.

SATURN_Nuclear_CDT

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Applicant Eligibility

Candidates will have, or be due to obtain, a Master’s Degree or equivalent from a reputable University in an appropriate field of Engineering. Exceptional candidates with a First Class Bachelor’s Degree in an appropriate field will also be considered.

Application Process

Candidates wishing to apply should complete the University of Liverpool application form [How to apply for a PhD – University of Liverpool] applying for a PhD in **Degree Title** and uploading: Degree Certificates & Transcripts, an up-to-date CV, a covering letter/personal statement and two academic references.

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Candidates wishing to discuss the research project should contact the primary supervisor, Prof. Maulik Patel [[email protected]], those wishing to discuss the application process should discuss this with the School PGR Office [[email protected]] or specific question on the SATURN CDT framework for PhD to [email protected]