The Thermal Performance of Polymers used for the Encapsulation of Ion Exchange Materials

Submersible caesium removal units (SCRUs) are deployed in fuel storage ponds at a number of power stations. The units comprise a pre-filter to remove suspended particulate in the pondwater, two cartridges containing IONSIV IE-911 for caesium removal and a post-filter for removal of any IONSIV fines released from the cartridge. The intention is to emplace IONSIV cartridges into a waste container. The cartridge will then be immobilised using a polymer encapsulant, which is designed to be of sufficiently low viscosity to infiltrate the fine voidage between the IONSIV granules. This report develops an understanding of the thermal performance of polymer for the encapsulation of ion exchange material and addresses the concern that toxics may be produced on heating. Thermal Gravimetric Mass Spectrometer (TGA/MS) and Scanning Electron Microscopy (SEM) analyses were conducted on two different materials: 1. Ion exchange resin in a polymer binder: IONSIV IE-911 in DT-901. This is representative of the packaging of the waste (IONSIV) in an encapsulant. 2. Polymer encapsulant: DT-901. Results indicate that the release of unreacted monomer around 121