UKAEA Journals

Showing 1 - 10 of 1616 Journals Results
2021
UKAEA-CCFE-PR(21)13

Tridiagonal matrix inversion is an important operation with many applications. It arises frequently in solving discretized one-dimensional elliptic partial differential equations, and forms the basis for many algorithms for block tridiagonal matrix inversion for discretized PDEs in higher-dimensions. In such systems, this operation is often the sca…

Preprint
2021
UKAEA-CCFE-PR(21)12

Small punch creep (SPC) testing represents an effective way to rapidly assess the creep performance of novel materials and potentially monitor degradation of in-service components. Recent progress in standardisation has also led to improvements in data analysis. However, estimation of equivalent uniaxial stresses is still somewhat challenging and h…

Preprint
2021
UKAEA-RACE-PR(21)02

This article presents and practically validates an identifier-critic-based approximate dynamic programming (ADP) method to online address the optimal tracking control problem for nonlinear continuous-time unknown systems. The imposed assumption on precisely known system dynamics is obviated via a neural network (NN) identifier. A static contro…

Preprint
2020
UKAEA-RACE-PR(21)01

Remote handling systems are commonly used for decommissioning and maintenance of hazardous environments, specially in the nuclear sector. The necessity for a more realistic and accurate user interaction with the remote environment has led research towards the usage of immersive technologies such as augmented and virtual reality. In order for thi…

Preprint Published
2021
UKAEA-CCFE-PR(21)11

The SOLPS-ITER simulations of European DEMO reactor, with 450 MW of power to be exhausted, show an increased operational space compared to the conventional single-null configuration. Using a reduced model with fluid neutrals and bundled impurities, we assessed the existence and the boundaries of operational space for DEMO with the conventional sing…

Preprint
2021
UKAEA-CCFE-PR(21)10

The divertor target plates are the most exposed in-vessel components to high heat flux loads in a fusion reactor due to a combination of plasma bombardment, radiation and nuclear heating. Reliable exhaust systems of such a huge thermal power required a robust and durable divertor target with a sufficiently large heat removal capability and lifetime…

Preprint
2021
UKAEA-CCFE-PR(21)09

Ion cyclotron emission (ICE) driven by perpendicular neutral beam-injected (NBI) deuterons, together with the distinctive ICE driven by tangential NBI, have been observed from heliotron-stellarator plasmas in the Large Helical Device (LHD). Radio frequency radiation in the lower hybrid range has also been observed, with frequency dependent on plasm…

Preprint
2021
UKAEA-CCFE-PR(21)08

A survey of the correlation between temperature and density gradient lengths ( and ) has been performed for the near SOL regions in the ASDEX Upgrade tokamak. In common with previous studies, the near SOL temperature and density gradient length ratio, , is found to be close to unity across a wide range of plasmas. However, it is found that it is po…

Preprint Published
2021
UKAEA-CCFE-PR(21)07

A study of a dataset of JET plasma with the Be/W ITER-like wall (JET-ILW) shows that reaching the edge MHD ballooning limit leads to confinement degradation. However, unlike JET plasma with a carbon wall (JET-C), the JET-ILW plasma stays in a marginal dithering phase for a relatively long period, associated with a higher a ( 20%) H-mode density lim…

Preprint
2021
UKAEA-CCFE-PR(21)06

This work addresses an overview of the recent progress, associated risks and development plans of structural materials for in-vessel components (IVCs) in DEMO plants. Reduced Activation Ferritic Martensitic Steels form the primary structural materials for most DEMOs IVCs and will be the focus of the paper. An overview of EU- and J-DEMO programs …

Preprint