Development of a Quantitative, Radiation-Resistant Feeding Pump for Use in Extraction Chromatography Techniques for MA(III) Recovery

Atomic Energy Agency has been working on development of extraction chromatography technology for recovery of trivalent minor actinides (MA(III): Am, Cm) from high-level radioactive liquid waste generated in reprocessing of spent nuclear fuel.In this project, a diaphragm pump with radiation resistant is being developed for use in feeding the liquid on the recovery system.In this study, the degradation behavior of ethylene-propylene-diene (EPDM) rubber, selected as a candidate diaphragm material for diaphragm pumps, was quantitatively evaluated by irradiation tests.The rubber samples were immersed in nitric acid solution under tensile load and irradiated with gamma rays.After irradiation tests, tensile testing and dynamic mechanical analysis were conducted to the rubber samples.When the total dose increased, scission of the molecular chains on the rubber samples progressed in priority resulting in a decrease in the molecular weight.On the other hand, the viscoelasticity of the rubber is maintained even after irradiation of about 3.0 MGy.Irradiation tests were also performed on diaphragm pumps incorporating this EPDM rubber.The degradation behavior was similar to that of the rubber samples with the same total dose.