Long-term behaviour of TRU-waste-bearing ceramics
The aluminium-silicate ceramic matrix KAB 78, developed for the immobilisation of TRU wastes, has been doped with 20 wt% of Pu(238)O(2), in order to irradiate the matrix by the same alpha-dose over a period of three years, as would be accumulated within a storage time of about 100,000 years, when loaded with real TRU waste. The Pu(238)-doped ceramic KAB 78 was investigated, by means of ceramographic methods, while the accumulated alpha-dose increased up to 8.33 x 1.0 E9 Gy (9.4 x 1.0 E18 alpha-decays/g). Special attention was directed to the development of the microstructure, the crystalline state and the lattice constants of the matrix phases, as well as to stored energy as a function of the accumulated alpha-dose. The lattice constants of the matrix phases corundum and mullite were found to be only slightly enlarged. No sign of metamictisation beginning was detected. Changes in the microstructure did not occurr and the amount of stored energy has been determined to be less than 11 J/g. In order to study the corrosion behaviour of the Pu(238)-doped ceramic and ceramics loaded with real dissolver residues, leach tests were performed over a period of 214 days, using either Q-brine or Dl-water of up to 200 C. Leach rates, based on the total alpha-activity, were found to be slightly higher when leaching the Pu(238)-doped ceramics. Reaction zones of 150 up to 600 micron thickness were formed, with a significant decrease of Si, whereas the concentrations of Al and Pu remained unaffected.
Bibliographic Reference: EUR 13602 EN (1991) 53 pp., FS, ECU 6.25
ISBN: ISBN 92-826-2931-7
Record Number: 199111282 / Last updated on: 1994-12-02
Original language: en
Available languages: en