The ultimate safety margins of ITER: a demonstration of the safety potential of fusion

The fail-safe nature of the fusion energy reaction, modest radioactive inve ntories, multiple layers of confinement, and passive means for decay heat r emoval combine to make ITER 'safe' with little dependence on engineered, de dicated 'safety systems' for public protection. In this paper, we summarize our detailed assessment of very low probability or so called hypothetical accidents to show that ITER meets the 'no evacuation' objective and to demo nstrate the safety potential of fusion. By providing strong confidence that the design (and operation) of the facility protects the public, there shou ld no technical justification for dependence on public mitigative actions a s a backup for hypothetical events. Other objectives of this analysis are t o show the robustness of the defense in depth approach and to demonstrate t hat there are no cliff edge effects. (C) 1999 Elsevier Science S.A. All rig hts reserved.