Radiation effects on separations materials and processes

This paper briefly summarizes published information on the effects of ionizing radiation on separation processes and materials. Special emphasis is given those processes, solvent extraction, ion exchange, and precipitation, that have application in removing radioactivity from nuclear waste solutions. The separation and eventual isolation of any radionuclide requires a knowledge of the effect of radiation on the separations process itself and on the materials used in the process. The higher the radiation dose rate, i.e., the more concentrated the radionuclides being processed, the more important is this knowledge. In some cases, such as the separation of intense alpha emitters or the treatment of concentrated solutions of fission products, consideration of the effects of the radiation is a critical factor in the design of the separations materials and in the implementation of the process. When ionizing radiation interacts with a chemical system, chemical bonds are broken unstable intermediates are formed, and, if thermodynamically possible, new compounds are formed. Formation of these new compounds can drastically change the chemical and physical properties of the system. Many books have been written concerning radiation effects and the radiation chemistry that creates them. Recently a handbook has been published which is an excellent source of general and specific information on the subject (Tabata). Depending upon the specific separations system, radiation effects usually don't become significant until after does in the range 106 to 107 rads. Prior to discussing radiation effects on specific separation processes or materials, it is helpful to consider the radiation dose rates to typical solutions or materials being processed