Predictions of local, regional and global radiation doses from iodine-129 for four different disposal methods and an all-nuclear future

The radioactive isotope 129I produced by nuclear fission becomes globally distributed if released to the environment. The consequences of several options for management of 129I are discussed. Estimates are presented of radiation doses from the 129I produced in generating 1000 GW(e).a of nuclear electricity, the total production expected in Canada up to about 2040. Individual thyroid dose rates from 129I, and accumulated collective effective dose equivalents to three groups are compared for four 129I management strategies. These groups are: local persons living in the immediate vicinity of a discharge zone from a fuel reprocessing facility or waste disposal vault in the Canadian Shield, regional persons living in the lower Great Lakes basin, and average global persons. The four management strategies studied were: atmospheric discharge from a reprocessing facility, ocean dumping, subseabed disposal, and isolation in a deep vault in plutonic rock in the Canadian Shield. Doses associated with each of these options are compared with each other and with proposed Canadian regulatory limits. Estimates are also presented of doses to the same groups from fission-product 129I, if fission supplied all future world energy needs. The two management options considered were geological disposal in vaults that would each eventually discharge 129I at the rate estimated for a disposal vault in the Canadian Shield, and ocean dumping. Again, doses arising from these options are compared with each other and with proposed regulatory limits. The second comparison allows estimates to be made of the time at which such intensive use of fission could produce unacceptable levels of 129I in the environment