Shielding design options for the TF magnets of ITER

Optimization studies performed to design an efficient shield to protect the toroidal-field (TF) magnets of the International Thermonuclear Experimental Reactor (ITER) are described. Several options for the shield design were examined and many shielding materials have been evaluated. The pure stainless steel/H/sub 2/O shield does not satisfy the magnet radiation limits. When boron carbide, lead, or boron steel is incorporated in the shield, all design limits are met. The midplane of the inner legs and the top and bottom parts of the magnets suffer the greatest damage because of the limited space for the shield. The safety factors associated with the different magnet responses were quantified. These factors account for the increase in damage due to the presence of the assembly gaps between the shield modules and the uncertainties in data, codes, and modeling.>