Journals

Showing 21 - 30 of 1482 Journals Results
2020
UKAEA-CCFE-PR(20)89

With a lack of plasma disruptions and current-driven instabilities, stellarators are potentially an attractive option for a fusion power plant. Previous system studies have been performed to optimise a HELIAS (HELIcal-axis Advanced Stellarator) 5-B power plant using PROCESS, however these have been based around a single design point. In…

Preprint
2020
UKAEA-CCFE-PR(20)88

The efficient confinement of fast ions is crucial to the development of a fusion power plant. Sawtooth crashes are a manifestation of an internal kink instability, which can severely degrade this confinement. The effect of these on a fast ion population can be investigated using fast-ion deuterium-alpha (FIDA) spectroscopy, where charge exchange re…

Preprint
2020
UKAEA-CCFE-PR(20)86

Focussed ion beam (FIB) milling can be used to reveal sub-surface fracture and deformation below indents in materials. However, evolution of residual stresses around the indent impression cause changes to the crack morphology during the FIB cross-sectioning procedure. Berkovich nanoindents in single crystal hexagonal (6H) silicon carbide cause radi…

Preprint
2020
UKAEA-CCFE-PR(20)83

This paper presents results of extensive analysis of mode excitation observed during the operation of the Alfvén Eigenmode Active Diagnostic (AEAD) in the JET tokamak during the 2019-2020 deuterium campaign. Six of eight toroidally-spaced antennas, each with independent power and phasing, were successful in actively exciting stable MHD modes in 47…

Preprint
2020
UKAEA-CCFE-PR(20)82

Non-linear MHD simulations play an essential role in active research and understanding of tokamak plasmas for fusion energy. The development of MHD codes like JOREK is a key aspect of this research effort. In this paper, we present a fully-working version of the full-MHD model in JOREK, a significant advancement from the reduced-MHD model used for …

Preprint
The published version of this paper is currently under embargo and will be available on 15/10/2021
2020
UKAEA-CCFE-PR(20)80

Reduced activation ferritic steels are an attractive option for use in large structural components surrounding tokamak plasmas in future fusion power plants, but their ferromagnetic response to the confining magnetic fields must be properly understood. Simultaneously, the advantages of operating at high plasma elongation push tokamak designs toward…

Preprint
2020
UKAEA-CCFE-PR(20)81

The suitability of post-weld heat treatments are often measured in terms of reducing residual stress and/or ensuring hardness homogeneity. Here we use detailed digital image correlation to quantify the localised deformation behaviour of laser welded Eurofer-97 both with and without a normalising and tempering treatment. This is coupled with detaile…

Preprint
2020
UKAEA-CCFE-PR(20)78

During an accident with loss-of-coolant and air ingress in DEMO, the temperature of tungsten first wall cladding may exceed 1000oC and remain for months leading to tungsten oxidation. The radioactive tungsten oxide can be mobilized to the environment at rates of 10 – 150 kg per hour. Smart tungsten-based alloys are under development to…

Preprint Purchase
2020
UKAEA-CCFE-PR(20)79

Point defects in body-centred cubic Fe, Cr and concentrated random magnetic Fe-Cr are investigated

using density functional theory and theory of elasticity. The volume of a substitutional

Cr atom in ferromagnetic bcc Fe is approximately 18% larger than the…

Preprint