Assessment of the behaviour of metallic uranium during encapsulated product evolution

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At Sellafield site in Cumbria, significant quantities of spent metallic uranium fuel is stored in legacy pond facilities alongside skips containing zeolites and 'bit-bins' containing parts of fuel rods. There is an urgent activity to retrieve and repackage these materials and in doing so materials which have been slowly corroding under a layer of pond sludge (predominantly Magnesium hydroxide with lesser quantities of Aluminium and Uranium) will be exposed to mechanical disturbance and a rapid change in corrosion environment; especially considering a removal of the material for notional 'dry' storage in 3 cubic metre steel storage containers.Additional work is required to understand the rates and mechanisms of uranium corrosion when it is encapsulated in sludge, both magnesium sludge or much denser uranic sludge. ObjectivesThe project will investigate the fundamental mechanisms by which uranium metal will corrode when encapsulated in sludges of different types (Mg-hydroxide and uranic sludges) also examining the mechanisms and extent for hydrogen gas hold-up in the sludge, produced by metallic corrosion. A further objective of the PhD will be the establishment of a series of long-term corrosion experiments that investigate different sludge and water chemistries and simulate both existing wet conditions and then material drying conditions expected for retrieval to 3M3 storage boxes.CollaborationThe project will be of the utmost quality, drawing upon extensive expertise and well-established analytical resources for research on uranium and other reactive metals. The academic supervisors (Scott and Springell) have strong and established academic track records with numerous publications on uranium metallurgy and corrosion, as well as strong working collaboration on uranium corrosion with both Sellafield and the NNL. The project will use cutting edge analytical methods and approaches