The effect of the high-aspect-ratio design parameters on ITER containment structures

A proposal has been made to improve the performance of ITER (International Thermonuclear Experimental Reactor) by modifying the reference design point. The high-aspect-ratio design (HARD) proposal increases the aspect ratio to four, increases the central toroidal field to 7 T, and decreases the peak plasma current to 14.8 MA. Systems studies indicate that the HARD parameters provide improved technology testing capability by increasing the neutron wall loading while maintaining the CDA (conceptual design activity) physics constraints. Changes in configuration, loading, stresses, and other factors for the containment structure components, based on the HARD parameters, have been investigated. In general, the HARD configuration has only minor effects on the containment structures. Advantages include better distribution of resistance and lower loads and stresses for the vacuum vessel. Disadvantages include much higher electromagnetic loads on the inboard blankets, less margin in the stability parameter, and the requirement to put passive loops on the inboard blankets. No significant change in cost would be expected