Reinforcement of TRU-containing wastes in a ceramic matrix
Aluminium silicate based ceramic materials have been evaluated as an alternative waste form for the incorporation of TRU wastes. These waste forms are free of water and cannot generate hydrogen radiolytically, show good compatability between the compounds of the waste and the matrix, and are resistant against aqueous solutions, heat and radiation. The main process steps are :(i) pretreatment of the liquid waste (concentration, denitration, neutralisation, solid-liquid separation), (ii) mixing with ceramic raw materials and forming, and (iii) heat treatment with T(max) of 1300 C for 15 minutes. The waste load of the ceramic matrix has been increased gradually from 20 to 50, and in some cases to 60 wt.%. The resulting TRU-waste ceramics reveal densities from 2.03-3.90 g/cm3, compressive strengths from 70-450 N/mm2, and open porosities from 2-10 vol.%. The specific alpha-activity of the TRU-waste ceramics ranges between 6 E7 and 2.2 E9 Bq/g. As found by means of optical light and scanning electron microscopy, the waste particles, mostly TRU-oxides and noble metals and oxides are bonded tightly as inclusions with the fine grained matrix. The quality of the TRU-waste ceramics produced in the (semi)technical scale corresponds to that of the laboratory-scale specimens. The use of a ceramic matrix for containing TRU-waste offers options of high waste loadings (more than 20 wt.%) as well as the simultaneous ceramisation of several waste streams. This may contribute significantly to reducing the waste volume.
Bibliographic Reference: EUR 13509 DE (1991) 86 pp., FS, ECU 8.75
ISBN: ISBN 92-826-2771-3
Record Number: 199111032 / Last updated on: 1994-12-02
Original language: de
Available languages: de