Alumina as a Matrix for Fixation of Fission Products

Autor: Erich Zimmer, S.-O. Schmidt, K. Scharf
Rok vydání: 1991
Předmět:
Zdroj: MRS Proceedings. 257
ISSN: 1946-4274
0272-9172
DOI: 10.1557/proc-257-227
Popis: Fission products and α-emitters from reprocessing plants ( HAW ) are incorporatedinto a ceramic matrix consisting of 90 w/o α-AI2O3 The amount of HAW in the product is 10 w/o. The matrix is produced by a sol-gel technique using a boehmite powder and a SiO2 sol as starting materials. To reduce the sintering temperature seeding with α-AI2O3 particlesis applied. The first step of the process is mixing of the starting materials with the nitric acid containing HAW. This results in the production of a gel. The gel is extruded and subsequently dried at 105ºC. Calcination is carried out in a hydrogen containing atmosphere. Finally, the material is sintered at 1300ºC. During heat treatment only minor volatilization is observed. Even cesium is almost completely retained sinceit forms an aluminosilicate (Cs2O. xSiO2. yAI2O3; feldspar type). The waste product has a total leach rate of 4 * 10-7g * cm-2 d-1 at 97ºC as determined in a Soxhlet apparatus. Under the same conditions, specific leaching rates of radiologically important nuclides, such as cesium and strontium, are approximately 10-6 g * cm-2 d-1. The process has the advantage that commercially available starting materialscan be used. In addition, only a moderate sintering temperature is required and pressingbefore or during sintering is not necessary.
Databáze: OpenAIRE
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