Concept Design for Tritium Measurement System in STEP Fusion Reactor

UK Fusion Energy Ltd (UKFE) is seeking a supplier to develop a concept design for a laser-induced desorption system to measure tritium retention in first wall materials for the STEP (Spherical Tokamak for Energy Production) programme. STEP is the UK's flagship fusion energy initiative sponsored by the Department for Energy Security and Net Zero, aiming to build a prototype fusion power plant demonstrating net energy production and fuel self-sufficiency. Tritium management is critical for fusion plants, as tritium serves as fuel for deuterium-tritium reactions while being both radioactive and scarce. Accurate measurement of tritium retention is essential for fuel accountancy, demonstrating self-sufficiency, and monitoring component condition during plant operation. The successful supplier must develop a measurement system capable of functioning in extreme conditions including neutron radiation, strong magnetic fields, thermal loading, limited space, and radioactive environments. This initial concept design phase is expected to lead to subsequent detailed design, technology maturation, testing, and integration into the STEP tokamak, subject to future funding and programme approvals.