High-level radioactive waste fixation in sintered vitreous matrix
Description
The safe storage of high-level wastes from fuel elements reprocessing includes, as a first step, the fixation of the same in materials having a good resistance to the leaching in aqueous medium, such as borosilicate glass. As an alternative to the usual method of the molten glasses, a procedure for the sintering of a powdered glass and waste mixture at lower temperatures (600-700 deg C) has been developed, which minimizes the volatilization of active compounds during the process. Two glasses matrices of different composition and characteristics were used, to which the simulated wastes were added in the ratio of a 10% in weight of oxides. Two sintering techniques were employed 1: cold pressing and further sintering; 2: hot pressing and sintering under pressure. The densities were measured, the microstructure of the samples was analyzed and leaching essays were made in distilled water. The pellet's microstructure was observed by means of optical microscopy, by reflection in polished samples and by transparency in thin slices. The presence of crystalline compounds was analyzed by means of x rays and electron microprobe. The results have shown the convenience to continue with hot pressing essays, because a denser product with a higher resistance to the leaching is thus obtained. (M.E.L.)
Availability note (English)
MF available from INIS under the Report Number; Also available from Comision Nacional de Energia Atomica, Buenos Aires (AR).Abstract (Spanish)
El almacenamiento seguro de los residuos de alta actividad provenientes del procesamiento de combustibles irradiados, comprende como primer paso la fijacion de los mismos en bloques de materiales con buena resistencia a la lixiviacion en medio acuoso, tales como los vidrios borosilicados. Como alternativa al metodo usual de los vidrios fundidos, se ha desarrollado el proceso de sinterizado de vidrio y residuos, ambos en polvo y a menores temperaturas (600-700 grados C), lo que minimiza la volatilizacion de componentes activos durante el procesamiento. Se utilizaron dos matrices de vidrio de composicion y caracteristicas diferentes, a las que se agregaron los residuos simulados en un 10% en peso de oxidos. El sinterizado se hizo mediante dos tecnicas 1: prensado en frio y posterior sinterizado; 2: Prensado en caliente y sinterizado bajo presion. Se determinaron las densidades y microestructura de las muestras y se hicieron ensayos de lixiviacion en agua destilada. La microestructura de las pastillas fue observada mediante microscopia optica por reflexion en muestras pulidas y por transparencia en cortes delgados. La presencia de cortes cristalinos se analizo mediante rayos X y microsonda electronica. Se determino la conveniencia de continuar los ensayos en caliente, ya que se obtiene un producto mas denso y con mayor resistencia a la lixiviacion. (M.E.L.)Files
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Additional details
Additional titles
- Original title (Spanish)
- Fijacion de residuos de alta actividad en matriz vitrea sinterizada
Publishing Information
- Imprint Pagination
- 9 p.
- Report number
- CNEA-NT--21/87
INIS
- Country of Publication
- Argentina
- Country of Input or Organization
- Argentina
- INIS RN
- 20006660
- Subject category
- S12: MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES;
- Descriptors DEI
- BOROSILICATE GLASS; HIGH-LEVEL RADIOACTIVE WASTES; LEACHING; MATRICES; RADIOACTIVE WASTE DISPOSAL; REPROCESSING; SINTERING; SOLIDIFICATION; SPENT FUELS; UNDERGROUND DISPOSAL
- Descriptors DEC
- DISSOLUTION; ENERGY SOURCES; FABRICATION; FUELS; GLASS; MANAGEMENT; MATERIALS; NUCLEAR FUELS; RADIOACTIVE MATERIALS; RADIOACTIVE WASTES; REACTOR MATERIALS; SEPARATION PROCESSES; WASTE DISPOSAL; WASTE MANAGEMENT; WASTES
Optional Information
- Secondary number(s)
- CNEA-REPO--25.