Dr P Shanthraj, Prof M Preuss
Applications accepted all year round
Competition Funded PhD Project (European/UK Students Only)
About the Project
Zirconium alloys are most commonly used as the fuel cladding material in nuclear reactors. Hydrogen uptake in these alloys occurs as a result of aqueous corrosion during service, and the absorbed hydrogen precipitate out of solution as hydrides once its solubility limit in the alloy is exceeded. The presence of hydrides has a negative impact on the structural integrity of the fuel clad, and can result in its premature failure through a mechanism known as delayed hydride cracking (DHC). While the effective management of this issue is an area of concern for the nuclear industry, DHC is a complex failure process and our current understanding of the underlying mechanisms is limited.
The structure and chemistry of the zirconium-hydride interface is expected to play an important role in determining the severity of embrittlement. Its propagation is facilitated through the formation of intermediate, less-stable hydride phases, and the kinetics of this complex process will strongly influence the volume fraction, size and orientation of the resulting hydrides. Knowledge and control of the internal structure and chemistry of the zirconium-hydride interface is thus critical to the effective management of DHC.
This modelling project will focus on investigating how the microstructure will affect the growth kinetics of the zirconium-hydride interface in real-world alloys. A model for hydride growth will be developed that incorporates the thermodynamics of the zirconium-hydrogen system, diffusion and phase transformation kinetics, as well as micromechanical driving forces. The modelling tool will enable rapid exploration over a wide microstructural parameter space and will be applied to investigate the sensitivity of hydride growth rates, their orientation and structure to changes in alloy composition, grain boundary and texture distribution, as well as the presence of defects.
The detailed and systematic understanding of hydride growth kinetics thus obtained will be used to develop improved strategies for DHC mitigation through material and microstructure control.
Funding Notes
The project is aligned with the new EPSRC Programme Grant MIDAS. This particular PhD project will receive top -up funding (£15k/annum) from Rolls-Royce or EDF and the tuition fees will also be covered. The duration is 3.5 or 4 years. The proposed start date is October 2019.
Applicants should have or expect to achieve at least a 2.1 honours degree in Mathematics or a physical science. The applicant should have demonstrated an aptitude for the more mathematical and theoretical aspects of their degree.
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