High Fidelity Digital Twins of Fusion Plant

Driven by an urgent need to transition away from test-based design to a “simulation first” approach to engineering, extreme scale simulation and newly emerging AI methods offer a timely opportunity to address the challenge of designing the world’s first fusion powerplants. It is now possible to perform “High Fidelity” (HiFi) simulations of complex, strongly coupled multi-physics system of systems problems such as the tokamak. The advent of the exascale offers the possibility that simulation may finally be powerful and “actionable” enough to pre-empt emergent phenomena that are typically only discovered once plant becomes operational. At scale, by combining detailed CAD models that closely resemble real plant with fully coupled multi-physics models and access to ExaFlop GPU supercomputers, models will start to closely resemble Grieves’ and Vickers’ definition of the “digital twin” [1].

Several UKAEA facilities are planning digital twins, for example CHIMERA [2], a multi-physics thermal hydraulic / electromagnetic test facility, and MAST-U [3], UKAEA’s Spherical Tokamak. These are being used as test cases to assess the utility of HiFi digital twins and their promise for accelerating and de-risking commercial fusion. A key ingredient will be emulators such as GANNs, PINNs or other AI methods (e.g. neural PDE operators) that can replace, augment or accelerate the more traditional simulation tools.

[1] Grieves, M., Vickers, J. (2017). Digital Twin: Mitigating Unpredictable, Undesirable Emergent Behavior in Complex Systems. In: Kahlen, J., Flumerfelt, S., Alves, A. (eds) Transdisciplinary Perspectives on Complex Systems. Springer, Cham. https://doi.org/10.1007/978-3-319-38756-7_4

[2] T.R. Barrett, M. Bamford, B. Chuilon, T. Deighan, P. Efthymiou, L. Fletcher, M. Gorley, T. Grant, T. Hall, D. Horsley, M. Kovari, M. Tindall, The CHIMERA facility development programme, Fusion Engineering and Design, Volume 194, 2023, 113689, ISSN 0920-3796, https://doi.org/10.1016/j.fusengdes.2023.113689.

[3] Morris, William, et al. "MAST upgrade divertor facility: a test bed for novel divertor solutions." IEEE transactions on plasma science 46.5 (2018): 1217-1226.