Fusion Reactor Passive Safety and Ignitor Risk-Based Regulation

The passive safety strategy for fusion can be summarized as three options: Inventory-based passive safety, Mobility-based passive safety, and Confinement-based passive safety. The determination of the dose limits for the public must follow a risk-based approach, where “risk” is the product of frequency times consequence. Ignitor is a high magnetic field tokamak, aimed at studying the physics of ignited plasmas. The site chosen for construction is the nuclear site of Saluggia (Northern Italy). The safety goal for Ignitor is the classification as a mobility-based passively safe machine. This choice is based on several assessments, and application of the ALARA principle. Evaluation of plant inventories and operation, and experience from other fusion machines have lead to conclusion that the above limits are the lowest reasonably achievable. The limits, however stringent, to not present a burden to plant operations. A comparison of Ignitor and ITER risk-based curves is finally carried out.