chapter  25
Advancement in Membrane Methods for Liquid Radioactive Waste Processing: Current Opportunities, Challenges, and the Global Scenario
Pages 44

Conventional technologies used for liquid low-and mediumlevel radioactive waste processing as precipitation coupled with sedimentation, ion exchange (IX), and evaporation (EV) are energy consuming or introduce the third phase that results in production of secondary wastes (sludge from sedimentation tanks, spent sorbent from IX columns, or efuents from resin regeneration). These wastes need additional treatment and decontamination. All these disadvantages may be avoided by membrane methods that have already found the application in the eld of liquid radioactive waste processing. The most advanced are technologies based on pressure-driven membrane processes: microltration (MF), ultraltration (UF), and reverse osmosis (RO). The choice of the process depends on waste composition or parameters that have to be reached during processing, for example, decontamination factors (DFs) in relation to the limits dened in national or international regulations, volume reduction coef-cients, or necessity of recycling some components of the solution. Different installations have to be used for treating the wastes from nuclear power plants or reprocessing plants and for processing the wastes from production of radiopharmaceuticals and medical diagnostics. Radioactive wastes from production of radioisotopes and medicine are usually classied as low-and medium-level wastes; they contained mainly β and γ emitters, while the wastes from the waste processing plants contain α-bearing elements, which can destroy polymeric membrane material. Very often, the organic solvents and complexing agents or acids are present in this type of wastes. The wastes coming from nuclear reactor operation contain the ssion (e.g., 89Sr, 90Sr, 124Sb, 132Te, 134Cs, 136Cs, 137Cs, 140Ba, 141Ce) as well as corrosion (60Co, 58Co, 51Cr, 54Mn, 59Fe, 65Zn, 95Zr) products.