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UKAEA-CCFE-PR(23)1722023
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…
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UKAEA-CCFE-PR(23)1402023
We investigated the athermal irradiation-induced swelling and creep in iron subjecting to the application of external uniaxial stress. We studied this through atomic scale simulations using the creation-relaxation algorithm. We also calculated the defect relaxation volume density tensors (or eigenstrain) as a function of external uniaxial stress. B…
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UKAEA-CCFE-PR(24)2442022
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…
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UKAEA-CCFE-PR(24)2382022
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…
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UKAEA-CCFE-PR(24)052022
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…
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UKAEA-CCFE-PR(23)1312022
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…
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UKAEA-CCFE-PR(21)682021
Using the notion of eigenstrain produced by the defects formed in a material exposed to high energy neutron irradiation, we develop a method for computing macroscopic elastic stress and strain arising in components of a fusion power plant during operation. In a microstructurally isotropic material, the primary cause of macroscopic elastic stress an…
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UKAEA-CCFE-PR(21)602021
Using atomistic simulations based on the creation-relaxation algorithm, we explore the evolution of microstructure in irradiated zirconium over a broad range of radiation exposure. In agreement with experimental observations, we find that at relatively low temperatures, microstructure evolves towards an asymptotic dynamic steady state forming at…
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UKAEA-CCFE-PR(21)562021
Hydrogen isotopes are retained in materials for fusion power applications, changing both hydrogen embrittlement and tritium inventory as the microstructure undergoes irradiation damage. But modelling of the highly damaged regime – over 0.1 displacements per atom (dpa) – where asymptotic saturation is observed, is difficult because a highly dama…
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UKAEA-CCFE-PR(21)012021
The ability of a body-centered cubic metal to deform plastically is limited by the thermally activated glide motion of screw dislocations, which are line defects with a mobility exhibiting complex dependence on temperature, stress, and dislocation segment length. We derive an analytical expression for the velocity of dislocation glide, based on a s…
Showing 1 - 10 of 13 UKAEA Paper Results