Comparative radiological assessment of decommissioning options for fusion energy plants

Four options for fusion plant decommissioning—“Early Stage 3”, “Safestore”, “In-situ Decommissioning” and “Safestore with Recycle”—are compared on the basis of overall radiological impact. This impact is calculated as a weighted sum of six components representing the collective doses to workers and the public, and the risk to individual members of the public. Calculations are performed for two variants of a reference design, one employing standard structural materials and the other partially utilizing low activation materials. For the standard plant, Early Stage 3 has the lowest overall impact, while the impact of the Safestore option is also low. Both the Safestore with Recycle and In-situ Decommissioning options have a high relative impact for the standard plant, while the In-situ Decommissioning option would be precluded by the risk to individual members of the public. For the low activation variant, the In-situ Decommissioning option is again precluded but the other options give low impacts. This scoping study indicates that the use of low activation materials could be beneficial with respect to the freedom of choice of decommissioning options.