USING HOT ISOSTATIC PRESSING FOR RADIOACTIVE WASTE ISOLATION PURPOSES

The paper summarizes the findings of a study focused on hot isostatic pressing (HIP) technique implemented by the Khlopin Radium institute. The equipment was designed and manufactured at the Kharkov’s Physics and Technology Institute. The installation provided a pressure of up to 400 NPa with the pressing temperature of up to 1250 °C. The experiments were carried out on installations located in hot cells in the radiochemical department (Gatchina city). Samples of materials for HLW immobilization (titanate ceramics of the synroc type, stabilized cubic zirconia) and matrices for ¹²⁹I immobilization based on copper iodide and metallic copper were obtained. The leaching rate from these samples of HLW elements (simulators) amounted to (0.5—1.5)·10–9 g/(cm²·day). Despite the high-performance characteristics of the materials obtained, some problems were revealed associated with the remote maintenance of equipment and the lack of industrial design analogues. Considering the experience gained, we believe that fairly simple equipment can be designed implying no complex systems and providing minimum preparatory operations. Joint efforts of technologists and designers will enable the automatization of equipment management and control through local control systems. Material loading and unloading operations can be robotized as well. Such technical solutions are expected to be in demand at industrial facilities for HLW final disposal (or when handling damaged fuel during the decommissioning of radiation and nuclear hazardous facilities).

 

Keywords: radioactive waste, hot isostatic pressing, liquid radioactive waste, calcination, crystalline mineral-like matrices, plasma chemistry, solid-phase synthesis.