Radiation tolerant robotics for fusion is closing a four-order-of-magnitude gap

A Kuka robotic arm inside a controlled test enclosure under Project FORT, the FFIC-funded programme integrating radiation tolerant automation for STEP and EU-DEMO maintenance operations

(Image courtesy of Veolia Nuclear Solutions)

The robotic systems that will maintain STEP and EU-DEMO are not yet qualified for deployment. Building them is not primarily a mechanical challenge — it is an electronics one. Standard silicon-based components begin to fail at total integrated gamma doses of around 100 Gy. Inside a fusion vessel during or after operations, the environment demands tolerance above 1 MGy. That is a four-order-of-magnitude gap, and closing it is now the defining engineering constraint for fusion remote handling.

Why radiation tolerant robotics Is device-defining for STEP and EU-DEMO

UKAEA has identified robotic maintenance as one of six essential challenges for commercially viable fusion energy, placing it alongside plasma science, materials, and fuel handling. The authority goes further than calling it important. It describes remote maintenance as device-defining, meaning the architecture of a fusion power plant must be designed around robot access from the outset. Maintenance ports are long and narrow. Residual magnetic fields of around 40 mT complicate conventional motor design. Activated components create gamma dose environments that standard industrial electronics cannot sustain long-term.

This framing has direct procurement implications. For the most demanding in-vessel applications, robotics suppliers cannot simply adapt solutions developed for other sectors. STEP and EU-DEMO require a dedicated supply chain, built and qualified specifically for these conditions. The Fusion Futures Industry Capability programme is how UKAEA is funding that build-out, contracting UK industry to develop and de-risk the core technology stack before either programme needs it operational.

Project P170, known as the Fusion Oriented Robotic Technology programme or FORT, is one of those contracts. Veolia’s nuclear solutions business is working with UKAEA’s RACE facility to develop radiation tolerant automation across three workstreams: integrating rad-hardened vision systems with robotic platforms, developing software for dynamic path planning and collision avoidance, and testing automation in representative fusion environments. The programme is using a Kuka industrial robotic arm as the platform for integration and testing.

What the electronics research actually shows

On motion systems, UKAEA researchers have validated a rad-hard-by-design resolver-to-digital system achieving positional accuracy to within 0.05 degrees in fusion-relevant radiation environments, with a rated tolerance above 1 MGy. Performance is comparable to conventional industrial systems, and the verified design is a candidate drop-in replacement for existing components, a significant result for fusion robotics qualification pathways.

On sensing, UKAEA has completed feasibility work on a portable rad-hard LIDAR prototype built around GaN and InGaN components, with a design tolerance targeting approximately 1 MGy. InGaN laser diodes in the design retained 80 percent emissivity at 1.5 MGy. Standard COTS LIDAR silicon semiconductors fail at doses as low as 100 Gy. Component selection and architecture are established. Gamma irradiation trials of the prototype are the defined next phase.

These two bodies of work represent the technical foundation that Veolia and UKAEA’s RACE team are building on through FORT’s vision integration workstream. Moving from validated components to qualified robotic systems tested in representative fusion environments is precisely the gap that FFIC-funded programmes like FORT are designed to close. STEP targets first operations around 2040. The remote handling systems that will maintain it need qualification well before that date, and FORT is drawing on Veolia’s established expertise in radiation-tolerant automation to advance both safety and efficiency in fusion maintenance operations. That work is already underway.

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