Development of the passive safety concept for ITER

Since the start of the ITER design effort, safety experts have attempted to guide designers in the development of a machine that will demonstrate the potential safety and environmental advantages of fusion. Offsite dose limits, based on regulatory requirements, have been translated into release rates or radiological inventories, which provide useful guidance to designers. The ITER team is attempting to protect the public against major accidents to the extent possible with passive means, that is, without the relying on active systems. The concept of passive safety is developed here by the US safety team for internal events and for external events that are within the envelope of design basis accidents selected for ITER. In addition to overall safety guidance, implications of passive safety for ITER systems, as envisioned by the US safety team, are discussed. An approach to implementing passive safety in ITER with reference to the blanket, plasma facing components, fuel cycle systems, plasma shutdown, and magnet design, is described. The need for a confinement building is addressed, and the role of such a building in the context of passive safety is also discussed. 6 refs., 1 fig., 3 tabs