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Atomic Scale Modelling of Zirconium Alloys and Hydrogen in Zirconium By Simon Lumley Supervised by Dr Mark Wenman, Prof. Robin Grimes and Dr Paul Chard-Tuckey.

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Presentation on theme: "Atomic Scale Modelling of Zirconium Alloys and Hydrogen in Zirconium By Simon Lumley Supervised by Dr Mark Wenman, Prof. Robin Grimes and Dr Paul Chard-Tuckey."— Presentation transcript:

1 Atomic Scale Modelling of Zirconium Alloys and Hydrogen in Zirconium By Simon Lumley Supervised by Dr Mark Wenman, Prof. Robin Grimes and Dr Paul Chard-Tuckey

2 Modelling Zirconium Introduction: why model zirconium and hydrogen? Methods: density functional theory. Results: alloy solution energies. Results: lattice Strains. Future work.

3 Introduction: Zirconium The main component in the Zircaloy series of metals. Zircaloy is used in PWR, BWR and CANDU reactors. Its main use is as a fuel cladding material. A PWR fuel assembly being placed into storage.

4 Introduction: Why Zirconium? Adequate mechanical and thermal properties. Good corrosion resistance. Low thermal neutron capture cross-section. But...It is subject to hydrogen embrittlement. An optical micrograph of Zircaloy after heavy exposure to hydrogen. Kim YS, Ahn SB, Cheong YM. J. Alloys Cmpds. 2007;429:

5 Introduction: Zirconium Alloys

6 Methods: Density Functional Theory Kinetic Energy Potential Many Body Interaction Electron Density Interaction

7 Methods: Solution Energies The following cells were modelled in VASP: Done for niobium, tin and yttrium. Substitutional cells contained 54 atoms in total (1.85 at%).

8 Results: Solution Energies – Nb and Y eV eV eV eV

9 Results: Solution Energies – Sn eV eV

10 Methods: Solution Energies - Intermetallics

11 Results: Solution Energies – Sn eV eV

12 Results: Lattice Strains Y Sn Nb V Cr Fe

13 Future Work Extending solution energy calculations to other elements. Can we model hydrogen binding with intermetallic phases? Does the lattice strain play a role in this? Do intermetallic compounds provided a location for hydrogen to be absorbed. Thank you for your time. Any Questions?


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