UKAEA Journals

Showing 1 - 10 of 25 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 reality …

Preprint
2019
UKAEA-CCFE-PR(19)11

Increased neutralisation and hence injected neutral beam power can be achieved by increasing the neutraliser target. This has the potential to increase the loading on the ion source backplate due to backstreaming electrons. Measurements of the backplate power loading due to backstreaming electrons are presented for the JET EP2 neutral beam injector…

Preprint Published
2015
CCFE-PR(17)39

In normal operation the JET neutral beam injectors have the operating gas supplied to the ion source and the neutraliser. For tritium operation the gas is supplied to both the ion source and neutraliser at a point close to the earth grid (“grid gas”) due to the difficulty in producing a gas line with a secondary containment and a ceramic break fo…

Preprint Published
2015
CCFE-PR(17)26

For the initial phase of MAST-U operation the two existing neutral beam injection systems will be used, but must be substantially upgraded to fulfil expected operational requirements. The major elements are the design, manufacture and installation of a bespoke bending magnet and Residual Ion Dump (RID) system. The MAST-design full energy dump is b…

Preprint Published
2015
CCFE-PR(17)23

We describe the operational experience of the JET actively cooled duct liner and compare it with the previous inertially cooled duct. The paper discusses the initial conditioning of the duct liner during restart commissioning and subsequent high power performance. The new duct was conditioned in 48 plasma pulses during its first time commissioning …

Preprint Published
2015
CCFE-PR(17)25

The JET Neutral Beam Injection (NBI) system is the most powerful neutral beam plasma heating system currently operating. Optical Interlocks were installed on the beam lines in 2011 for the JET Enhancement Project 2 (EP2), when the heating power was increased from 23 MW to 34 MW. JET NBI has two beam lines. Each has eight positive ion injectors oper…

Preprint Published
2015
CCFE-PR(15)114

The linear and quasi-linear plasma response to the n = 3 and n = 4 (n is the toroidal mode number) resonant magnetic perturbation (RMP) fields, produced by the in-vessel edge localized mode control coils, is numerically studied for an ITER 15MA H-mode baseline Scenario. Both single fluid and fluid-kinetic hybrid models are used. The inclusion of dr…

Preprint Published
2015
CCFE-PR(15)112

The Small Negative Ion Facility (SNIF) at CCFE has been undergoing continuous development and enhancement to both improve operational reliability and increase diagnostic capability. SNIF uses a CW 13.56MHz, 5kW RF driven volume source with a 30kV triode accelerator. Improvement and characterisation work includes: • Installation of a new “L” t…

Preprint Published
2014

A significant functional upgrade is planned for the Mega Ampere Spherical Tokamak (MAST) device, located at Culham in the UK, including the implementation of a notably greater neutral beam injection power. This upgrade will cause the emission of a substantially increased intensity of neutron radiation for a substantially increased amount of time up…

Published
2014

The three dimensional plasma boundary displacements induced by applied nonaxisymmetric magnetic perturbations have been measured in ASDEX Upgrade, DIII-D, JET, MAST and NSTX. The displacements arising from applied resonant magnetic perturbations (RMPs) are measured up to ±5% of the minor radius in present day machines. Good agreement can be found …

Published