ATOMIC ENERGY RESEARCH ESTABLISHMENT HARWELL (ENGLAND)
The studies described in this Report have been carried out on five batches of hulls resulting from the reprocessing of fuel from the Prototype Fast Reactor at Dounreay. Direct immobilization in cement and decontamination have been examined as possible routes for treating the hulls, and as a background to this work the activities on them have been charcterized. Five batches of hulls have been examined, corresponding to fuel with burn-ups in the range 07.3. They have been examined visually, and found to be mostly either shiny from lower breeder sections or dark from core or upper breeder regions. A number of low temperature chemical techniques have been used to remove actinides and fission products from the hulls. The methods included nitric acid at reflux temperature, nitric acid with ceric ions added, alkaline permanganate solution, and oxalic acid with hydrogen peroxide corrosion inhibitor. 10 mm sections of hulls have been immobilized in two cements in which either sand or blast furnace slag was used to extend the ordinary Portland cement.