The influence of neutral beam optimization for DEMO on injector design

Surrey, E.; Benn, Anthony Wedgwood; Jenkins, I.; Porton, M.; Timmis, William; Turner, Andrew

doi:10.1016/j.fusengdes.2012.03.028

Cited by 14 publications

(6 citation statements)

References 12 publications

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“…The maximum tangency radius for the neutral beams is determined by the size and shape of the TF coils, as the beams need to pass between them at an angle. This may be an important constraint on the achievable neutral beam current drive, as this is usually maximum when the tangency radius is equal to or slightly greater than the major radius (1), (2). Figure 2 shows the geometry and symbols used.…”

Section: Access Required For Neutral Beamsmentioning

confidence: 99%

“PROCESS”: A systems code for fusion power plants – Part 2: Engineering

Kovari

Fox

Harrington

et al. 2016

Fusion Engineering and Design

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PROCESS is a reactor systems codeit 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 algorithms submitted by collaborators can be incorporatedfor example safety, first wall erosion, and fatigue life will be crucial and are not yet taken into account. This paper describes algorithms relating to the engineering aspects of the plant. The toroidal field (TF) coils and the central solenoid are assumed by default to be wound from niobium-tin superconductor with the same properties as the ITER conductors. The winding temperature and induced voltage during a quench provide a limit on the current density in the TF coils. Upper limits are placed on the stresses in the structural materials of the TF coil, using a simple two-layer model of the inboard leg of the coil. The thermal efficiency of the plant can be estimated using the maximum coolant temperature, and the capacity factor is derived from estimates of the planned and unplanned downtime, and the duty cycle if the reactor is pulsed. An example of a pulsed power plant is given. The need for a large central solenoid to induce most of the plasma current, and physics assumptions that are conservative compared to some other studies, result in a large machine, with a cryostat 36 m in diameter. Multiple constraints, working together, restrict the parameter space of the optimised model. For example, even when the ratio of operating current to critical current in the TF coils is increased by a factor of five, the total coil cross-section decreases only a little, because of the need for copper stabiliser, insulation, and structural support. The result is that the plasma major radius hardly changes. It is these surprising results that justify the development of systems codes.

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Section: Access Required For Neutral Beamsmentioning

confidence: 99%

“PROCESS”: A systems code for fusion power plants – Part 2: Engineering

Kovari

Fox

Harrington

et al. 2016

Fusion Engineering and Design

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“…An investigation of a DEMO scenario with 2 MeV NBI is carried out in [26], including a comparison with the 1 MeV NBI case. A study on the requirements and consequent design of a 1.5 MeV NBI for DEMO is presented in [27].…”

Section: Nbi Current Drive Analysis By Metismentioning

confidence: 99%

Modelling of pulsed and steady-state DEMO scenarios

Giruzzi

Artaud

Baruzzo³

et al. 2015

Nucl. Fusion

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Scenario modelling for the demonstration fusion reactor (DEMO) has been carried out using a variety of simulation codes. Two DEMO concepts have been analysed: a pulsed tokamak, characterised by rather conventional physics and technology assumptions (DEMO1) and a steady-state tokamak, with moderately advanced physics and technology assumptions (DEMO2). Sensitivity to impurity concentrations, radiation, heat transport models has been investigated. For DEMO2, the impact of current driven non-inductively by Neutral Beams has been studied by full MonteCarlo simulations of the fast ion distribution. The results obtained are a part of a more extensive R&D effort carried out in the EU in order to develop a viable option for a DEMO reactor, to be adopted after ITER for fusion energy research.

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“…This part of the model follows the approach initially developed by Chan [9]; it includes the same processes and the solution method is virtually identical to the DC transport model [10,11,12]. The gas density and temperature depend on the interaction between the three positive ion species and electrons with the gas, with the only major difference being the fact that thermal electron rates must be used as opposed to the fast primary electron rates as used in [1,2,3].…”

Section: Gas Density and Temperature And Plasma Transportmentioning

confidence: 99%

A 1D ion species model for an RF driven negative ion source

Turner

Holmes²

2017

AIP Conference Proceedings

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Effect due to plasma electrode adsorbates upon the negative ion current and electron current extracted from a negative ion source AIP Conference Proceedings 1869, 030025 (2017) Abstract.A one-dimensional model for an RF driven negative ion source has been developed based on an inductive discharge. The RF source differs from traditional filament and arc ion sources because there are no primary electrons present, and is simply composed of an antenna region (driver) and a main plasma discharge region. However the model does still make use of the classical plasma transport equations for particle energy and flow, which have previously worked well for modelling DC driven sources. The model has been developed primarily to model the Small Negative Ion Facility (SNIF) ion source at CCFE, but may be easily adapted to model other RF sources. Currently the model considers the hydrogen ion species, and provides a detailed description of the plasma parameters along the source axis, i.e. plasma temperature, density and potential, as well as current densities and species fluxes. The inputs to the model are currently the RF power, the magnetic filter field and the source gas pressure. Results from the model are presented and where possible compared to existing experimental data from SNIF, with varying RF power, source pressure.

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The influence of neutral beam optimization for DEMO on injector design

Cited by 14 publications

References 12 publications

“PROCESS”: A systems code for fusion power plants – Part 2: Engineering

“PROCESS”: A systems code for fusion power plants – Part 2: Engineering

Modelling of pulsed and steady-state DEMO scenarios

A 1D ion species model for an RF driven negative ion source

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