LEACH TEST OF SPENT ION-EXCHANGE RESINS SOLIDIFIED IN CONCRETE

This paper deals with the cementation of spent ion exchange resins arising at Loviisa NPS. The purpose of the experiment was to study the long-term stability of the solidification product. The spent resin used for the preparation of the test specimens was a mixture of bead-formed cation and anion resins. The leachant used in this experiment was local groundwater from the site of Loviisa NPS, equilibrated with granulated cement. The test method applied originates from Dr. Brodersen /1/. The radionuclides of interest to this dynamic long-term leach testing were Cs-134, Cs-137 originally present in spent resins and Sr-85, which was added to the wet resin mixture prior to cementation. After each leach period, gamma activities of leachant and granulate were measured. Based on gamma measurements, the penetration depths and cumulative fractional release rates for Cs-134, Cs-137 and Sr-85 have been calculated. Leach tests have been running for about 4 years and 19 leachant exchanges have been performed. Tests are still in progress and will be continued for up to 5 years.