Project Outline
The project will be hosted in the School of Chemistry and the School of Mechanical, Aerospace and Civil Engineering, and will also involve work at the Manchester X-ray Imaging Facility (MXIF). 

Background
It is government policy that high level radioactive wastes (HLW), including spent fuel, vitrified products of reprocessing and plutonium will be disposed of via deep geological disposal in a dedicated Geological Disposal Facility (GDF). It is currently envisioned that packages for safe disposal of HLW in a GDF consist of the wasteform e.g. HLW in glass, the metal waste container; a clay (bentonite) buffer and the surrounding geosphere. Significant quantities of waste has already been generated and packaged. Packages must be extremely durable, capable of withstanding both radioactive and thermal damage, and designed to ensure that HLW is confined and immobilised safely over the long timescales required for radiation levels to decay, such that radiotoxicity is reduced to minimise harm. A GDF is a highly complex, multi-component and multi-process entity involving timescales as long as 1 million years. For HLW, after closure of the GDF, processes that affect the engineered system include heat generation, irradiation, degradation of engineered barriers, re-saturation with modified groundwater, waste container corrosion, gas generation and microbial degradation. It is critical to demonstrate that the bentonite component of a multi-barrier system will continue to perform the necessary safety functions of confinement and immobilisation in a GDF environment, in spite of these complex and interlinked process.

The Project
The project is suitable for a student with an interest in carrying out multidisciplinary work at the modelling/experimental interface. The successful applicant will apply a pore network model (PNM) of mass transport through porous media to analyse the effects of changing pore space structure on macroscopic transport coefficients, such as permeability and diffusivity. The PNM will be used to link transport coefficients with changes in the underlying physical structure of the ECB; this will provide a mechanistic understanding of pore space evolution with time, as a result of environmental factors, ultimately allowing the diffusivity of radionuclides in the ECB to be predicted. The student will generate a discrete geometrical space for diffusive flow calculations, informed by pore size distributions (PSD) determined experimentally using X-ray tomography (XRT) of a sample matrix of clays exposed to heat, radiation and canister corrosion products. Local diffusivities and pore space connectivity will be dependent on these mechanisms that change the pore space. The aim of this research is to predict the performance of the ECB in terms of impermeability and sorption capacity using a pore network model (PNM). The project will require close interaction with the Radioactive Waste Management Directorate (RWMD) of the Nuclear Decommissioning Authority (NDA) for selection of materials and conditions that will answer significant questions related to the Disposal System Safety Case (seehttp://www.nda.gov.uk/aboutus/geological-disposal and references therein).

Further information about relevant research carried out in Manchester can be found here:http://www.dalton.manchester.ac.uk, http://www.rcrd.manchester.ac.uk, http://crr.manchester.ac.uk

Qualification
Applicants should have or expect a good (I or II(i)) honours degree (or an equivalent degree) in Chemistry, Engineering, Materials, Earth Science, Geology, Environmental Science.

Further Information
Please submit a cover letter and CV with your application. The cover letter must contain a short paragraph covering your research interests and your motivation for the project.

For more information and informal enquiries please contact Dr Carolyn Pearce:Carolyn.pearce<στο>manchester.ac.uk

The studentship is fully funded for UK/EU citizens (EU citizens subject to residence conditions). The funding covers tuition fees and a stipend for 3.5 years (14,057 in 2015/16).

Please see application process at:
http://www.manchester.ac.uk/postgraduate/howtoapply/