Development of high temperature adsorption for treating waste problem

An important part of the nuclear fuel cycle management in Russia is solidification of HLW and their safe disposal. Prior to final disposal radioactive waste has to be conditioned and described in detail. Intense research activities have been carried out in recent years at Russian Research Institute for Chemical Technology to develop the method of high temperature adsorption of metals. With this method, radionuclides adsorbed and immobilized in a porous inorganic sorbent, for example, silica gel at temperature 100 - 130 degrees C followed by calcination of saturated granules at 800 - 1000 degrees C. Using silica gel for immobilizing radioactive waste offers a wide range of possibilities for different waste streams to meet the requirements of final products. Due to radiolysis of water in silica gel, hydrogen production can not be prevented. In this paper the results of the experimental study of HLW forms behaviors under simulated repository conditions is presented. The experiments performed in this study are directed towards determination of radiation stability of silica gel. It is devoted to investigation the role of ionization damage as well as to acceptability of accelerated testing results for reliable prediction of long-term behavior of final solid material containing beta gamma nuclides. The examinations were supposed to answer the following questions: mechanism of gas-formation; characterization of parameters influencing the rate of gas-formation