Journals

Showing 21 - 30 of 1464 Journals Results
2020
UKAEA-CCFE-PR(20)70

Determining tensile properties from small punch test is being pursued actively in the nuclear industry due to the limited volume of material such tests use compared with standard tests which can be critical when considering active or development samples. One of the crucial challenges in harnessing the full potential of this technique is formulating…

Preprint
2020
UKAEA-CCFE-PR(20)69

Molybdenum is a potential material for future nuclear fusion experiments and power plants. It has good thermo-mechanical properties and can be readily fabricated, making it attractive as an alternative material to tungsten (the current leading candidate) for high neutron flux and high thermal load regions of fusion devices. Unfortunately, exposure …

Preprint
2020
UKAEA-CCFE-PR(20)68

The poloidal harmonics of the toroidal normal modes of an unstable axisymmetric tokamak plasma are employed as basis functions for the minimisation of the 3D energy functional. This approach presents a natural extension of the perturbative method considered in [M.S. Anastopoulos Tzanis et al, Nuclear Fusion 59:126028, 2019]. This variational formul…

Preprint
2020
UKAEA-CCFE-PR(20)67

Disruption prediction and avoidance is a critical need for next-step tokamaks such as ITER. The Disruption Event Characterization and Forecasting Code (DECAF) is used to fully automate analysis of tokamak data to determine chains of events that lead to disruptions and to forecast their evolution allowing sufficient time for mitigation or full avoid…

Preprint
2020
UKAEA-CCFE-PR(20)66

Similarity experiments are conceived to study on existing tokamak facilities, characteristics of scenarios found on other devices or planned for new machines. The possibility of doing similarity experiments is linked to the physics processes studied and it gives in any case partial views which can be found in integrated way only on the planned…

Preprint
2020
UKAEA-CCFE-PR(20)65

A novel approach using Bayesian inference has been implemented to interpret the filamentary dynamics measured by a Langmuir probe fixed to a reciprocating assembly on MAST. The model describes the system as a superposition of time-displaced filaments and a fixed background component. Each filament is parameterised in terms of a characteristic r…

Preprint
2020
UKAEA-CCFE-PR(20)64

The JET outboard divertor targets are the in-vessel components which receive the largest heat flux density. Surface delamination, radial cracks, and tie rod failures have been observed in the outboard tungsten-coated CFC tiles, while bulk tungsten special lamellas were intentionally melted in dedicated experiments. These different types of damag…

Preprint
2020
UKAEA-CCFE-PR(20)23

To ensure optimal plasma performance at high Qfus for the baseline scenario foreseen for the International Tokamak Experimental Reactor (ITER), fuelling requirements, in particular for non-stationary phases, need to be assessed by means of integrated modelling due to different expected fuelling behaviour and additional challenges that need to be…

Preprint Purchase
The published version of this paper is currently under embargo and will be available on 05/05/2021
2020
UKAEA-CCFE-PR(20)22

A linear perturbation theory is used to model the MHD stability of tokamak equilibria under the application of external 3D magnetic perturbations [C.C. Hegna, Physics of Plasmas 21 :072502, 2014]. The symmetry breaking produces the coupling of toroidal n modes. We use ELITE [H.R. Wilson et al., Physics of Plasmas 9 :1277, 2002] to produce …

Preprint
2020
UKAEA-CCFE-PR(20)21

Local linear gyrokinetic simulations show that electron temperature gradient (ETG) instabilities are the fastest growing modes for kyρi >~ 0.1 in the steep gradient region for a JET pedestal discharge (92174) where the electron temperature gradient is steeper than the ion temperature gradient. Here, ky is the w…

Preprint