Lessons learnt from MAST Upgrade will aid the development of the Spherical Tokamak for Energy Production — or 'STEP' — the UK's first prototype fusion power plant. This £220 million, government-funded project is to be completed in the year 2040, and also borrows from MAST Upgrade the latter's more compact and efficient internal shape, pictured, which is more spherical than the classic ring-doughnut-like tokamak design