The MAST-Upgrade tokamak commenced operation with its first plasma at Culham Centre for Fusion Energy, the United Kingdom on 29 October 2020. As a result of the seven-year upgrade programme for the Mega Ampere Spherical Tokamak (MAST), essentially a complete new fusion device was built with a stronger magnetic field and higher heating power.
Prof. Ian Chapman, the chief executive of the UK Atomic Energy Authority said: “MAST Upgrade will take us closer to delivering sustainable, clean fusion energy. This experiment will break new ground and test technology that has never been tried before. It will be a vital testing facility on our journey to delivering the STEP fusion power plant.”
The MAST-Upgrade is a spherical tokamak with a thin central solenoid which differs from the traditional tokamak geometry (e.g. JET, JT-60SA, ASDEX-Upgrade etc.). Therefore, it allows a more compact design which radically reduces the unit cost of construction and operation. However, it presents several new challenges, too .
A task of the MAST-Upgrade programme is to support and enhance successful campaigns on the ITER with the required research and development impacts. It plays a role to explore opportunities in the design of spherical tokamak as a possible candidate for the European demonstration fusion power plant (DEMO). The upgrade allows achieving longer discharges up to 5 seconds which brings us closer to the quasi-continuous operation.
MAST-Upgrade is equipped with an effective pumping on the divertor chambers which allow various divertor geometries. The divertor system is responsible for the exhaust and impurity management in the fusion devices. Magnetic coils stretch the plasma to Super-X and snowflake (multipronged) configurations. That fact gives the plasma more time and space for radiation hence less heat reaches the wall of the vessel and the divertor plates which extend their lifetime .
Prof. Tony Donné, the programme manager for the EUROfusion said: “Warm-hearted congratulations to the MAST Upgrade team on behalf of the EUROfusion community. We are looking forward to the scientific results from this machine with its super-long divertor leg, which will give important guidance to ITER and DEMO.”
We wish a similarly successful future as the old MAST tokamak had!
A video of the first plasma is available here:
 MAST Upgrade Research Plan: https://ccfe.ukaea.uk/wp-content/uploads/2019/12/MAST-U_RP_2019_v1.pdf