MAST upgrade — Progress and engineering challenges

The Mega Amp Spherical Tokamak (MAST) is the centre piece of the UK's fusion research programme. In 2010, a MAST upgrade programme was initiated with 3 primary objectives, namely to contribute to: 1) Testing of 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's performance) and 3) Exploring the feasibility of using a spherical tokamak as a fusion Component Test Facility (looking at start-up, current drive, steady state behaviour, handling of high heat flux, plasma confinement, high beta operation and performance reliability). With the first phase of the MAST upgrade programme well under way, progress and engineering challenges will be reported in the areas of design, R&D and procurement. In particular, this will include the engineering challenges and solutions for the new divertor, the development of upgraded Toroidal Field (TF) coils to increase the toroidal field by a factor of 1.5, the approach adopted for the vertical position control (critical for this predominantly double-null device), the proposed auxiliary heating systems and the extensive diagnostic suite being developed to maximize the scientific output from the upgraded machine.