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UKAEA-CCFE-PR(25)3732024
Two closely-related candidate surrogate models for global tokamak plasma dynamics both exhibit spiking behaviour, which may be understood using concepts from the classical problem of particle motion in a well of potential energy. Numerical work indicates that when there is coupled evolution of the well’s properties, there is the bifurcation ca…
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UKAEA-CCFE-PR(25)3712024
Instabilities of Alfvén eigenmodes (AEs) are of significant concern because they can enhance the cross-field transport of alpha particles beyond the neoclassical level in magnetic fusion plasmas. The threshold value of alpha-particle pressure for exciting AEs depends critically on the damping rate of AEs. The damping mechanisms include kinetic dam…
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UKAEA-CCFE-PR(25)3722024
The crystal plasticity-based finite element method is widely used as it allows complex microstruc8 tures to be simulated and for direct comparison with experiments. In this paper, we introduce and demonstrate a new crystal plasticity code (OXFORD-UMAT for Abaqus® 9 ), which we have 10 made freely available online to encourage other …
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UKAEA-CCFE-PR(25)3702023
14C is produced from the activation of N and O with high-energy neutrons. Due to its long half-life, high residence time in the environment and ease of assimilation into living matter, it is a major concern for the transportation of activated material and disposal of radioactive waste materials. This paper reports the discrepancy in the 14C prod…
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UKAEA-CCFE-PR(25)3692024
Plasma detachment in tokamaks is useful for reducing heat flux to the target. It involves interactions of the plasma with impurities and neutral particles, leading to significant losses of plasma power, momentum, and particles. Accurate mapping of plasma emissivity in the divertor and X-point region is essential for assessing the rel…
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UKAEA-CCFE-PR(25)3682024
This research utilizes established cyclic deformation models to simulate the Bauschinger effect observed in copper monocrystal cantilever experiments during the initial bending and straightening phases. Crystal plasticity finite element simulations employing Armstrong-Frederick, Orowan-Sleeswyk, and various other backstress models have failed to…
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UKAEA-CCFE-PR(25)3672025
This study presents the validation of the finite element code ERMES 20.0, benchmarked against the well-established method-of-moments code TOPICA. The simulations focus on Ion Cyclotron Resonance Heating (ICRH) coupling for the JET A2 antennas. Validation is performed by comparing two key metrics: the scattering parameter matrix (S-matrix) and the …
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UKAEA-CCFE-PR(25)3652024
The effect of water chemistry, surface condition, pH moderator (LiOH vs. KOH), and Zn addition was investigated at 300 °C on the oxidation behaviour of reduced activation ferritic martensitic (RAF/M) EUROFER-97. EUROFER-97 is the proposed material for the water-cooled breeder blanket (WC-BB) section of DEMO, but its behaviou…
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UKAEA-CCFE-PR(25)3642025
The tokamak is a world-leading concept for produc- ing sustainable energy via magnetically-confined nuclear fusion. Identifying where to position the magnets within a tokamak, specifically the poloidal field (PF) coils, is a …
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UKAEA-CCFE-PR(25)3632024
The extreme working conditions of the in-vessel components in nuclear fusion reactors require remote laser-welding for maintenance. However, this process induces heterogeneous residual stress, which can interact with microstructures, degrading mechanical properties. Involving the high-temperature operating environmen…
Showing 121 - 130 of 2563 UKAEA Paper Results