AbstractRadiation transport calculations have been carried out to aid in the design of the reference shielding and breeding blankets proposed for the International Thermonuclear Experimental Reactor (ITER). The results of analyses suggest that both blanket assemblies in combination with the surrounding vacuum vessel provide adequate shielding for the toroidal field coils and reduce the heating and damage to levels commensurate with design guidelines. The induced activation levels and decay heat generation in the breeding blanket—vacuum vessel may qualify the assemblies for disposal as Class C low level waste based on US regulations. The nuclear performance of the shielding around neutral beam injection ducts and in the vicinity of the divertor vacuum pumping ports was also investigated. Preliminary results suggest that the proposed neutral beam injection and divertor port shielding is satisfactory in both cases.