UKAEA Papers

"Finite element models for radiation effects in nuclear applications"

• L. Reali
• S.L. Dudarev

Fusion reactor components will be exposed to fluxes of high energy neutrons while also being subjected to thermal, mechanical and magnetic loads. Exposure to neutron irradiation has numerous consequences, including swelling a…

"γ-photons and high-energy electrons produced by neutron irradiation in nuclear materials"

• L. Reali
• M.R. Gilbert
• M. Boleininger
• S.L. Dudarev

Neutrons interacting with atomic nuclei in most of the materials included in the current fusion reactor designs—notably tungsten, ferritic and stainless steels, copper alloys—generate a γ-photon flux that is comparable in magnitude and e…

"Evolution of nanocrystalline tungsten at low temperature due to irradiation-induced strains"

• Pui-Wai Ma
• Daniel R. Mason
• Steven Van Boxel
• Sergei L. Dudarev

We simulate effects of irradiation on nanocrystalline tungsten in the athermal high dose limit using the creation-relaxation algorithm, where microstructural evolution is driven not by thermally activated diffusion, but by fluctuating stresses resulting from the production and relaxation of defects. Over the entire interval of radiation exposure sp…

"Dislocation density transients and saturation in irradiated zirconium"

• Andrew Ralph Warwick
• Rhys Thomas
• Max Boleininger
• Ömer Koç
• Gyula Zilahi
• Gabor Ribarik
• Zoltan Hegedues
• Ulrich Lienert
• Tamas Ungar
• Christopher Race
• Michael Preuss
• Philipp Frankel
• Sergei Lvovich Dudarev

Zirconium alloys are widely used as the fuel cladding material in pressurised water reactors where a significant population of defects and dislocations is produced by exposure to neutrons. We present and interpret synchrotron microbeam X-ray diffraction measurements of proton- irradiated Zircaloy-4, where we identify a transient peak and the sub…

"Microstructure of a heavily irradiated metal exposed to a spectrum of atomic recoils"

• M. Boleininger
• D. R. Mason
• A. E. Sand
• S. L. Dudarev

At temperatures below the onset of vacancy migration, metals exposed to energetic ions develop dynamically fluctuating steady-state microstructures. Statistical properties of these microstructures in the asymptotic high exposure limit are not universal and vary depending on the energy and mass of the incident ions. We develop a model for the micros…

"Intense γ-photon and high-energy electron production by neutron irradiation: effect of nuclear excitation on transport of defects"

• L. Reali
• M.R. Gilbert
• M. Boleininger
• S.L. Dudarev

Effects of neutron irradiation on materials are often interpreted in terms of atomic recoils, initiated by neutron impacts and producing crystal lattice defects. We find that, in addition, there is a remarkable two-step process, strongly pronounced in heavy elements, involving the generation of energetic γ-photons in non-elastic collisions of n…

"Volume of a dislocation network"

• M. Boleininger
• S. L. Dudarev
• D. R. Mason
• E. Martínez

We derive a simple analytical line integral expression for the relaxation volume tensor of an arbitrary interconnected dislocation network. This quantity determines the magnitude of dislocation contribution to the dimensional changes and volumetric swelling of a material, and highlights the fundamental dual role of dislocations as sources of intern…

"Radiation-induced precipitation of chromium in Fe-Cr alloys containing C and N impurities: First-principles modelling and experimental observations"

• Mark Fedorov
• Jan S. Wróbel
• Andrew J. London
• Krzysztof J. Kurzydłowski
• Chu-Chun Fu
• Tonči Tadić
• Sergei L. Dudarev
• Duc Nguyen-Manh

Using exchange Monte Carlo (MC) simulations based on an ab initio-parameterized Cluster Expansion (CE) model, we explore the phase stability of low-Cr Fe-Cr alloys as a function of vacancy (Vac), carbon, and nitrogen interstitial impurity content. To parameterise the CE model, we perform density functional theory calculations for more than 1600 …

"Grand Challenges in Nuclear Engineering"

• S L Dudarev

"Parameterisation of an LSDA+U model for non-collinear magnetic configurations"

• S. L. Dudarev
• P. Liu
• D. A. Andersson
• C. R. Stanek
• T. Ozaki
• C. Franchini

Unraveling the complexity of non-collinear magnetism in materials with strongly correlated electrons is a considerable task that requires developing and applying state of the art theories and computational methods. Using the Coury model Hamiltonian, which includes spin and orbital degrees of freedom and generalizes the collinear Stoner Hamiltonian,…