UKAEA Journals

Showing 731 - 740 of 1674 Journals Results
2015
CCFE-PR(15)93

The occurrence of segregation in highly dilute alloys under irradiation is an unusual phenomenon that has so far eluded theoretical explanation. The fact that solute atoms segregate in alloys that, according to thermodynamics, exhibit full solubility, has significant practical implications, as the formation of precipitates strongly affects physical…

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2015
CCFE-PR(15)61

A methodology to compute the distribution of interatomic distances in highly concentrated multicomponent alloys is proposed. By using the unit cell parameter and bulk modulus of the elements involved, the method accurately describes the distortion in the lattice produced by the interaction of the different atomic species. To prove this, density fun…

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2015
CCFE-PR(15)03

The fuelling of plasmas by shallow frozen pellets with simultaneous mitigation of edge- localised modes (ELM) by external magnetic perturbation is demonstrated on the MAST tokamak. In these plasmas post-pellet particle loss is dominated by ELMs. It is shown that the size of post-pellet ELMs can be controlled by external magnetic perturbations. Post…

Preprint Published
2015
CCFE-PR(15)83

Mitigating edge localized modes (ELMs) with resonant magnetic perturbations (RMPs) can increase energetic particle losses and resulting wall loads, which have previously been studied in the vacuum approximation. This paper presents recent results of fusion alpha and NBI ion losses in the ITER baseline scenario modelled with the Monte Carlo orbit fo…

Preprint Published
2015
CCFE-PR(15)62

Engineering and technical constraints on Neutral Beam Injection (NBI) in DEMO may determine the available beam energy and may also strongly impact the Neutral Beam Current Drive (NBCD) efficiency by restricting available beam tangential radii. These latter are determined by factors such as the inter-TF coil spacing, as well as the degree of requir…

Preprint Published
2015
CCFE-PR(15)44

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…

Preprint Published
2016
CCFE-PR(16)05

PROCESS is a reactor systems code – it assesses the engineering and economic viability of a hypothetical fusion power station using simple models of all parts of a reactor system. PROCESS allows the user to choose which constraints to impose and which to ignore, so when evaluating the results it is vital to study the list of constraints used. New …

Preprint Published
2015
CCFE-PR(15)58

Extending the ideal MHD stability code MISHKA, a new code, MISHKA-A, is developed to study the impact of pressure anisotropy on plasma stability. Based on full anisotropic equilibrium and geometry, the code can provide normal mode analysis with three fluid closure models: the single adiabatic model (SA), the double adiabatic model (CGL) and the inc…

Preprint Published
2015
CCFE-PR(15)13

A large number of materials exist which have been labeled as low activation structural materials (LAM). Most often, these materials have been designed in order to substitute-out or completely remove elements that become activated and contribute signi cantly to shut-down activity after being irradiated by neutrons in a reactor environment. To date, …

Preprint Published
2015
CCFE-PR(15)68

It has long been recognised that the shortage of external tritium sources for fusion reactors using D-T, the most promising fusion fuel, requires all such fusion power plants (FPP) to breed their own tritium. It is also recognised that the initial start-up of a fusion reactor will require several kilograms of tritium within a scenario in which radi…

Preprint Published