Review of Tokamak Fusion Machine Safety Systems

Fusion power, particularly tokamak-based designs, offers a promising long-term solution to the world’s growing energy demands and the challenges of climate change. This review evaluates the common safety systems found in four representative tokamak concepts, including ITER, the Fusion Nuclear Science Facility, the EUROfusion DEMO helium-cooled pebble bed, and the Advanced Research Innovation and Evaluation Study—Advanced Tokamak (ARIES-AT), to address critical hazards such as tritium, activated dust, material activation, and decay heat. Device-specific hazards can involve beryllium, hydrogen production, and activation products from lead, such as 210Po, and 203Hg. Current tokamak designs incorporate multiple safety systems, including the emergency shutdown system, dirsuption mitigation system, the vacuum vessel pressure suppression system, drain systems, and the detritiation system to manage the vacuum vessel pressure and possible tritium releases within the tokamak. Decay heat removal systems might also be needed to maintain in-vessel temperatures after shutdown and allow for maintenance. Further research is still needed to refine simulation tools and optimize safety designs to better understand the complexity of tokamak machines. As private industry and government agencies around the world accelerate the push toward commercial fusion power, transparency and robust safety standards will be essential to gain and maintain public trust.