129I targets for studies of nuclear waste transmutation

Nuclear incineration of long-lived fission products and minor actinides is being investigated as an alternative means of reactor waste disposal. 129I is of particular interest because of its long half-life and high mobility in the environment. Lead iodide targets of 129I for neutron capture cross-section measurements were prepared from 210 l fuel reprocessing waste solution containing 1.3 g l−1 iodine and other fission products. The iodine was separated by oxidation to I2 and extraction into chloroform, reduction to iodide by sodium sulphite and re-extraction into an aqueous phase. Iodide was precipitated using lead nitrate and dried. The chemistry was carried out batch-wise using 400 ml starting solution each time and recycling the chloroform. An extraction efficiency of about 90%, determined by γ-ray spectrometry, was achieved.