Study on immobilization of spent ion exchange resins generated at CIAE

At nuclear facilities the process for control system chemistry or the removal of radioactive containment in reactor primary coolants and /or cleanup of spent fuel pool, removal of boric acid and nuclear study centers have typically used organic ion exchange resin While their useful life ended, their ability of regeneration sharply depressed. Usually regeneration is not practiced. Due to considerable radioactive nuclei loading on it and in such a practice large amount of secondary liquid waste would be conducted to the waste treatment system. The used resin usually will be removed from the column and conveyed to shielded storage tank by compressed air system. Spent ion exchanger has been considered to be problematic wet solid waste. To avoid radiation dispersing into the environment, to make out an appropriate way for conditioning the waste is very important. According to contract with nation and Tsinghua university characterization of spent ion exchanger generated in our facilities has been finished at our lab. A direct cementation process has been set up and 1:1 scale demonstration has been fulfilled using formulation developed by Tsinghua University on the cementation process. Peak of temperature during hydration has been measured. Compressive strength and endure resistibility of the waste form for water and atmosphere have been tested. Results shown that performance of waste form can meet demand on national criteria. The process is easy to operate and its main advantages are described as following (1) the lay out of equipment is so compact that a shield from radiation for operation and maintenance is facilitated. (2) Type and shape of the resins involved in the experiment can completely represent that of reactors by now as well as in the future. (authors)