Business Design

  • 1. CAPABILITIES

    The NEPTUNE package will be capable of efficiently contributing ‘actionable’ results regarding the first wall to the reactor design process, specifically by speedily modelling the power deposited by the plasma

    • • subject to uncertainty quantification (UQ)

    • • using a modular suite of compatible components of minimal necessary complexity so as to ensure a workflow for rapid design, capable when needed of involving the latest high performance computers (HPC)

    In addition, the package will facilitate research into edge plasma physics by

    • • its ease of use, providing a suitable DSL for ‘high-level’ usage in Python/Julia to enable intuitive additions to existing models or the incorporation of new models, whereby equations may be defined using as explicit PDEs or as Lagrangians, and novel initial conditions imposed and new boundary conditions applied

    • • its ease of modification and development, by providing a set of well-defined objects/classes for tokamak plasma physics

    • • ease of incorporation of its component software into other physics packages

    • • offering a careful automatic control of numerical error

  • 2. STRATEGIC FIT

    National: The ExCALIBUR project is of national importance to UK government (represented initially by the BEIS and subsequently the DESNZ dept.) to demonstrate how to produce software that can exploit all the latest, most powerful hardware for scientific computation. The Fusion Modelling System (FMS) is one of ExCALIBUR’s principal use cases, for which project NEPTUNE will explore efficient development of new software for the Exascale.

    UKAEA: The software will facilitate world-leading R&D into fusion energy by UKAEA physicists and engineers, underpinned by external collaborators with a wide range of expertise. Its research contribution will be to improve detailed physical understanding of the often-turbulent plasma-wall interaction. Development of tokamak reactors will be facilitated if Exascale machines can be seamlessly integrated into the design workflow.

  • 3. BUSINESS DRIVERS

    Optimal power-handling at the wall will be critical for fusion reactors to be able to deliver sustainable fusion energy to the grid economically, if at all. Rapid exploration of parameter space is important to understand and optimise reactor designs, yet the existing software available to UK is dated so that it require years of experience to use well and is not suited to the latest HPC. Its replacement should remove a major handicap in the race to produce reactor designs.

  • 4. ASSUMPTIONS

    Funding of approx. \(\pounds \) 5 M over \(5\) years has been made available to UKAEA via the Strategic Priorities Fund under its ExCALIBUR programme to ready the UK for the Exascale era of computing. It is expected that further development of the NEPTUNE software will be funded at a similar if somewhat smaller level after 2025.

  • 5. RISKS

    Funding is via UK government and does not depend on the international situation.

  • 6. IMPACTS

    The new software should enable much faster iteration in respect of engineering design of the first wall of tokamak reactors. It should save much time and effort in the modelling of tokamak edge plasma physics. Generally, it should greatly reduce the training and computer time needed to obtain results compared to the existing software. There should also be benefits to UKAEA’s wider relationships with the Eurofusion E-TASC programme and with ITER.

  • 7. STAKEHOLDERS

    The successful outcome of the project should be a plus for the UK, UKAEA and most employees. The only losers will be those UKAEA staff and contractors who have devoted often years of their working lives to the dated software that NEPTUNE is designed to replace, and will undergo a loss of status in consequence. However, their physics skills and understanding will be valuable for guiding the NEPTUNE development to produce maximum benefits, hence they should soon recover position within UKAEA.

  • 8. GOVERNANCE

    The NEPTUNE project is overall governed by the UK governance known as PRINCE2 refs. [11, 12]. which demands oversight by a local committee known as a project board. Finance is subject to the usual UKAEA procedures and controls. The NEPTUNE project is further subject to reporting to UK Met Office as part of wider ExCALIBUR activities, whence there is a second layer of PRINCE2 oversight.

    The planned technical activities are outlined in the Science Plan ref. [4], it and all major changes and refinements are subject to external refereeing, following the ExCALIBUR procedures drawn up by UK Met Office consistent with the demands of the UK Strategic Priorities Fund ref. [13]. External procurements similarly follow the ExCALIBUR procedures drawn up by UK Met Office.