Radiation-induced stability and performance of ion exchange resins: Implications for the Reaktor Serba Guna G.A. Siwabessy (RSG-GAS) cooling system

The cooling system is vital in nuclear reactors, ensuring safe operation by regulating temperature, pH, and conductivity while maintaining reactor integrity. Reactors typically employ a two-tier system: a primary coolant that directly interfaces with the core and moderates neutrons, and a secondary circuit that removes heat. Continuous monitoring of primary quality is therefore essential. To maintain water chemistry within limits, purification units use ion exchange resins (IERs), with nuclear-grade resins preferred for their durability and radiation resistance. This study evaluates the long-term performance of nuclear-grade IERs employed in the Reaktor Serba Guna G.A. Siwabessy (RSG-GAS) reactor, benchmarked against industrial-grade resins. Structural and functional stability under irradiation were examined through Scanning Electron Microscopy (SEM), ion exchange capacity tests, and Neutron Activation Analysis (NAA). SEM showed structural degradation with increasing radiation dose (33, 66, and 100 Sv), though no major morphological differences were observed between resin types. Ion exchange capacity revealed superior efficiency of nuclear-grade resins (99.04%) over industrial-grade resins (98.00%). NAA confirmed that nuclear-grade resins introduced significantly fewer impurities, with reduced radionuclide activities compared to industrial-grade resins, which generated isotopes such as Co-60 and Fe-59. Nuclear-grade IERs demonstrated greater functional reliability and radiological safety, supporting their suitability for long-term application in reactor cooling systems.