[en] A processing method for spent fuels type Mtr from research reactors has developed in Nuclear Materials Division of Bariloche Atomic Center, this process involved the creation of ceramic matrix containing fuel and natural uranium in an isotopic solution, this project has named CERUS (Spanish acronym of 'Ceramización de Elementos Radioactivos en Uranio Sinterizado': Ceramming of radioactive elements with sintered uranium ). This process works with reduced volumes than a conventional vitrification, however because of some issues on the material resistance; we propose the addition of small amounts of glass with the idea to enhance the lixiviation properties of the final material. In this process is not considered the reprocessing possibility of the spent fuel. (author)