A STEP in the right direction: the Spherical Tokamak for Energy Production will aim to be operational by the 2040s (courtesy: UKAEA)
Five sites have been shortlisted as a potential home of the UK’s prototype fusion energy plant. Known as the Spherical Tokamak for Energy Production (STEP), it aims to be a working fusion reactor and have many of the features of a fully operational power station when operational in the 2040s. The five potential sites, announced today, include one in Scotland and four in England with a final decision on the plant’s location to be made by the end of 2022.
Five potential sites (courtesy: UKAEA)
STEP will be based on “spherical” tokamak technology that is currently being pioneered at the UK’s Culham Centre for Fusion Energy (CCFE). The CCFE is owned and managed by the UK Atomic Energy Authority (UKAEA) – which is located at the Culham Science Centre in Oxfordshire. It already houses two world-leading fusion tokamaks – the Mega Amp Spherical Tokamak (MAST-U) and the Joint European Torus.
In 2019 the UK government announced £222m towards a conceptual design report for a fusion power plant based on the spherical tokamak design. This would include prototyping components, carrying out materials research and robotics development, as well as computer modelling. The design effort will involve over 300 people and be complete in 2024. Despite the impact of the COVID-19 pandemic, the design work remains on track with the aim that the plant is fully operational by the 2040s.
After an open call for site proposals between December 2020 and March 2021, 15 sites were assessed. Following that process, five have now been picked to be studied further. They include four sites in England – Goole in East Riding of Yorkshire, Moorside in Cumbria, Ratcliffe-on-Soar in Nottinghamshire and Severn Edge in South Gloucestershire – while the fifth potential site is in Scotland in Ardeer, North Ayrshire.
“The shortlist of sites is a significant step for the programme as it helps bring this challenging, long-term endeavour to life [and] also increases our focus as we push on with design and delivery of what we hope is the world’s first fusion power plant prototype,” says Paul Methven, STEP programme director at UKAEA. “Through the next phase of assessment, we look forward to working with the shortlisted sites and local communities to gain a more in-depth understanding of the socio-economic, commercial and technical conditions associated with each site.”
A significant STEP
Earlier this year, researchers were buoyed by the first results on MAST-U. The spherical tokamak used a novel divertor that will likely be employed on STEP in which the new configuration led to a ten-fold reduction in waste heat load on the reactor walls.
The divertor is the hear exhaust system in the tokamak and if the results from MAST-U can be extrapolated to working fusion reactors, then exhaust material and other components would not need to be regularly changed – making such reactors more cost effective by allowing them to keep operational for longer.