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CCFE-PR(17)352015
The JET tokamak is unique amongst present fusion devices in its capability to operate at high plasma current, providing the closest plasma parameters to ITER. The physics benefits of high current operation have to be balanced against the risks to the integrity of the machine due to high force disruptions. The installation of the ITER-Like Wall (ILW…
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CCFE-PR(17)392015
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…
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CCFE-PR(17)232015
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 …
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CCFE-PR(17)252015
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…
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CCFE-PR(17)282015
The JET flywheel generator converters have operated since 1983 and for over 85,000 pulses. Problems with this plant are discussed, including corrosion, unbalanced flow and arcing within the liquid resistors; starting difficulties on both machines; and failure of the plug-braking transformers at energisiation. In 2012/13 two sets of thrust bearing p…
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CCFE-PR(15)052015
The aim of the Exhaust Detritiation System (EDS) of the JET Active Gas Handling System (AGHS) is to convert all Q-based species (Q2, Q-hydrocarbons) into Q2O (Q being indifferently H, D or T) which is then trapped on molecular sieve beds (MSB). Regenerating the saturated MSBs leads to the production of tritiated water which is stored in Briggs drum…
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CCFE-PR(15)1272015
Prolonged operation of the Joint European Torus (JET) in a set-up involving all ITER partners will be beneficial for ITER. Experiments at JET with its ITER-like wall and using a D–T plasma mixture will help to mitigate risks in the ITER research plan. Training of the ITER operators, technicians and engineers at JET will safe valuable time when IT…
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CCFE-PR(15)462015
A consistent deterioration of global confinement in H-mode experiments has been observed in JET [1] following the replacement of all carbon Plasma Facing Components (PFCs) with an all metal (‘ITER-like’) wall (ILW). This has been correlated to the observed degradation of the pedestal confinement, as lower electron temperature (T e ) values are …
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CCFE-PR(15)442015
The effects of poloidal asymmetries and heated minority species are shown to be necessary to accurately describe heavy impurity transport in present experiments in JET and ASDEX Upgrade. Plasma rotation, or any small background electrostatic field in the plasma, such as that generated by anisotropic external heating can generate strong poloidal den…
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CCFE-PR(15)322015
Results of the first dust survey in JET with the ITER - Like Wall (JET - ILW) are presented. The sampling was performed using adhesive stickers from the divertor tiles where the greatest material deposition was detected after the first JET - ILW campaign in 2011 - 2012. The emphasis was especially on metal particles (Be and W) with the aim to deter…
Showing 141 - 150 of 223 UKAEA Paper Results