Comparing the Deployment of Non-Ionic Polymers to Dewater Organic/ Inorganic Radwaste Suspensions: Learning from Experience-23549

Due to the high degree of scrutiny and regulation in the nuclear industry, standardization of chemical additives reduces the need for multiple holistic assessments. These include the impact on the operation of in sequence processing plants and long-term stability in a geological disposal facility. A non-ionic polyacrylamide commercial settling aid has been suggested to remove Magnox fuel degradation product colloidal challenges from UK ion exchange processes. This decision involved research and development stages which tested multiple settling aids and through analysis of settling performance and degradation products. As a result, the polyacrylamide was selected as the best available technique. It was then suggested that polyacrylamide could potentially be deployed to improve the clarification of liquors from pond water which has held a range of fuel types and debris. However, even though pond water is at a lower pH and consists of organic contaminants from algal blooms, the efficacy of the polyacrylamide was found to be superior in settling organic laden wastes. These wastes were more complex composition than the Magnox based material, where polyacrylamide was selected through experimental trials specific to Magnox based particles. In this paper the surface properties and floc structures of the two waste types are compared and the most influential properties on settling are scrutinized. Then learning from experience is discussed to identify how the Magnox settling aids programme could be used to accelerate the technology readiness level of deploying settling aids to tackle slow settling and colloidal challenges in other waste streams at the Sellafield site. Due to high levels of regulation, standardization of chemical reagents whose lifetime process and environmental impact from deployment to disposal have been reviewed is a powerful tool if the reagent can be applied to other processes. In this paper, the performance of a tailor selected non-ionic polymer to flocculate Magnox waste was compared to using the same polymer to flocculate a different organic laden waste with differing water chemistry. Key analyses were identified and learning from experience is discussed to accelerate the identification of other wastes which can also be targeted by the same polymer accelerating delivery.