MAST Upgrade – Construction Status

Abstract

The Mega Amp Spherical Tokamak (MAST) is the centre piece of the UK fusion research programme. In 2010, a MAST Upgrade programme was initiated with three primary objectives, to contribute to: 1) Testing reactor concepts (in particular exhaust solutions via a flexible divertor allowing Super-X and other extended leg configurations); 2) Adding to the knowledge base for ITER (by addressing important plasma physics questions and developing predictive models to help optimise ITER performance of ITER) and 3) Exploring the feasibility of using a spherical tokamak as the basis for a fusion Component Test Facility.With the project mid-way through its construction phase, progress will be reported on a number of the critical subsystems. This will include manufacture and assembly of the coils, armour and support structures that make up the new divertors, construction of the new set coils that make up the centre column, installation of the new power supplies for powering the divertor coils and enhanced TF coil set, progress in delivering the upgraded diagnostic capability, the modification and upgrading of the NBI heating systems and the complete overhaul of the machine control infrastructure, including a new control room with full remote participation facilities.

Towards a programme of testing and qualification for structural and plasma-facing materials in ‘fusion neutron’ environments

“…Other alternatives using a tokamak source, while their spectrum would be appropriate, are problematic either because of their tritium consumption, or, in the case of compact machines, due to extreme power handling and neutron damage to magnetic circuits. In the case of compact machines, current devices under operation and upgrade such as the national spherical tokamak experiment [143] and the mega-amp spherical tokamak upgrade [144] are an essential step in proving the concept's basic fusion power performance and ability to handle the extreme power loading on the divertor. Until this phase is achieved (likely in the next few years), a FNS based around a ST concept cannot be formulated with certainty.…”

Towards a fusion power plant: integration of physics and technology

“…• generation and control of dissipation in the divertor (i.e. detachment) with hydrogen 10 and impurity gases, and if necessary internal coils to allow fast sweeping of the strikepoints in event of reattachment…”

“…a no-ELM pedestal, and an intense x-point radiating zone), and whether the increased neutral density to deliver the gains are compatible with tritium handling (see next section). There are experiment and theory programmes to address the issues, for example based around MAST-U (Mega Amp Spherical Tokamak Upgrade) [10,11] which was designed to generate a wide range of configurations and divertor leg lengths, including a full super-X configuration (itself an integration challenge) and the advanced divertor programmes on TCV (Tokamak à Configuration Variable) [64], ASDEX Upgrade [65], DIII-D [66] and other devices worldwide. Providing confidence in time for initial decisions on either the reference single null or an alternative (longer leg explored here) will require ingenuity, or ways to allow significant design changes to be made late without adding too much delay (that would need rapid and effective design tools).…”

“…There is also much to learn from integration in new and recent facilities, for example JT-60SA [7], and others, e.g. [8][9][10][11][12][13][14][15] as well as from JET, the operating facility closest to ITER. There are also devices still in the design stage, e.g.…”

Performance of the BGSDC integrator for computing fast ion trajectories in nuclear fusion reactors

“…LOCUST is being used extensively to design plasma facing components, e.g. for MAST-U [33], and for studying the physics of fast ion distribution and loss due to Neoclassical Tearing Modes and the application of ELM Control Coils for ITER. It is part of the EUROfusion HALO programme, where it is used to study the implications of finite gyroradius effects, e.g.…”