UKAEA Papers

"Thermodynamics of oxide formation in W-Cr-Y smart alloys"

• Ryan Kerr
• Duc Nguyen-Manh
• Mark R. Gilbert
• Samuel T. Murphy

Tungsten is one of the primary materials for several applications in commercial fusion power plant designs, in particular for divertor targets and the first wall. In maintenance conditions or during a loss of coolant accident, tungsten is expected to reach temperatures at which it readily volatilises as tungsten trioxide in contact with air, potent…

"Molecular dynamics simulations of the effect of porosity on the thermal conductivity of Li2TiO3"

• M. Sanjeev
• M.R. Gilbert
• S.T. Murphy

Heat transfer is a key consideration in the development of tritium breeder blankets for future fusion reactors. For solid tritium breeder materials there is a a fine balance to be struck between high levels of porosity to encourage tritium release and minimising it to maintain the thermal and mechanical properties. Therefore, in this work we emp…

"Multilayer interface tracking model of pure tungsten oxidation"

• Shu Huang
• Ryan Kerr
• Samuel Murphy
• Mark R. Gilbert
• Jaime Marian

We present a numerical model to predict oxide scale growth on tungsten surfaces under exposure to oxygen at high temperatures. The model captures the formation of four thermodynamically-compatible oxide sublayers, WO2, WO2.72, WO2.9, and WO3, on top of the metal substrate. Oxide layer growth is simulated by tracking the oxide/oxide and oxide/metal …

"Thermal conductivity of non-stoichiometric Li2TiO3"

• Megha Sanjeeva
• Mark R. Gilbert
• Samuel T. Murphy

The transfer of heat through the breeder region of a future fusion reactor is a key component of its thermal efficiency. Development of advanced ceramic breeder materials based on Li2TiO3 seek to exploit its ability to accommodate significant non-stochiometry, however, it is not clear how deviations for the 50:50 mix of Li2O and TiO2 will affect…

"Anisotropic thermal conductivity in Li2TiO3"

• Megha Sanjeev
• Mark R. Gilbert
• Samuel T. Murphy

The high anisotropy in the thermal conductivity of lithium metatitanate, Li2TiO3, is shown using the classical simulation method of Molecular Dynamics (MD). The thermal conductivity along the z-direction is markedly lower than that in x and y. This characteristic could be exploited to favourably adjus…

"Energy spreading and stabilisation of plasma by application of a high frequency electric field"

• LG Kuo-Petravic
• M Petravic
• DR Sweetman
• EG Murphy
• RM Sinclair
• E Thompson

"Further remarks on the finite larmor radius stabilization theory for mirror machines"

• LG Kuo
• EG Murphy
• M Petravic
• DR Sweetman

"Effects of Neutron Irradiation on the Brittle to Ductile Transition in Single Crystal Tungsten"

• R.G. Abernethy
• J.S.K.-L. Gibson
• A. Giannattasio
• J.D. Murphy
• O. Wouters
• S. Bradnam
• L.W. Packer
• M.R. Gilbert
• M. Klimenkov
• M. Rieth
• H.-C. Schneider
• C.D. Hardie
• S.G. Roberts
• D.E.J. Armstrong

Only limited data exist on the effect of neutron irradiation on the brittle to ductile transition (BDT) in tungsten. This work investigates the increase in brittle to ductile transition temperature (BDTT) following neutron irradiation to 1.67 displacements per atom, using four-point bend tests over a range of temperatures (623 – 1173 K) and strai…

"Simulating electronically-driven structural changes in silicon with two-temperature molecular dynamics"

• R. Darkins
• D. M. Duffy
• P.-W. Ma
• S. T. Murphy

Ultrafast irradiation can drive the electrons in a material out of thermal equilibrium with the nuclei, producing hot, transient electronic states that modify the interatomic potential energy surface. We present, for the first time, a rigorous formulation of two-temperature molecular dynamics that can accommodate these electronic effects in the fo…