Even though fusion power relies on a nuclear process and uses radioactive tritium as one of its fuels, it does offer excellent performance with regard to safety and the environment. Importantly, there is no chain reaction since a fusion plasma shuts down naturally in any abnormal situation, there are only relatively low energies present to drive an accidental sequence, and the radioactive inventories are well confined by barriers already inherent in the design.

But to fully realise the potential safety performance, care must be taken to implement safety within the design. Today fusion power is investigated in scientific experiments. ITER’s successor DEMO is the first fusion device which will be planned like a power plant. The DEMO design process is incorporating nuclear safety issues from the very beginning of conception. That’s why, on 6th November, engineers working on the conceptual design of DEMO met with nuclear safety specialists to discuss the safety requirements and their implementation in the design. Around 30 people were present at the meeting, held at KIT, with many more participating remotely from the Research Units engaged in EUROfusion’s DEMO programme.

Safety and the environment is one of the eight missions of Europe’s Fusion Roadmap and the respective project called the meeting and invited all other groups working on different systems of the DEMO design, to submit their safety questions and implications for design requirements in advance. High on the meeting agenda were the safety requirements designed to eliminate or minimise the risk of radioactive material being released into the environment either during normal operation or theoretical accidents.

Discussions focussed on the extent to which different components in the DEMO design may contribute to the confinement of radioactive material, and on the targets that will be set for maximum radiological doses, even in extremely unlikely accident scenarios. Setting requirements that are both challenging yet achievable is a process that must involve both the safety team and the designers who are tasked with meeting the requirements. This meeting was an important step in the ongoing safety/designers interaction that will continue throughout the design process, thus ensuring the best possible safety and environmental performance of the DEMO plant.

Neill Taylor, CCFE