Long-term stability of high-level waste forms
The long-term stability of HLW forms is reviewed with regard to temperature, irradiation and aqueous corrosion in a geological environment. The focus is on borosilicate glasses, but the radiation stability results are compared with some HLW ceramics. Thermal Stability: most nuclear waste glass compositions have been adjusted to ensure a low final crystallised fraction. The crystallisation of highly active Pamela glass samples was similar to that of nonradioactive glass. Radiation Stability: no adverse irradiation damage was found in glasses doped with short-lived actinides; volume changes were small, no significant change in the leach rate was observed, and the fracture toughness increased. For most ceramics investigated, volume changes of up to 9%, amorphisation and higher leach rates were observed as a consequence of high alpha decay doses. For the KAB 78 ceramic, however, none of these effects was detected since the matrix was not subject to alpha recoil damage. Chemical Stability: it has been demonstrated that alteration by water depends largely on the repository conditions. Most clays act as silica sinks, and increase the glass corrosion rate. It is possible, however, to specify realistic temperature, pressure and environmental conditions to ensure glass integrity for more than 10,000 years.
Bibliographic Reference: Paper presented: 3rd European Community Conference on Radioactive Waste, Luxembourg (LU), Sept. 17-21, 1990
Availability: Available from (1) as Paper EN 35889 ORA
Record Number: 199110132 / Last updated on: 1994-12-02
Original language: en
Available languages: en