CH613301

Solid radioactive or toxic wastes are prepared for long-term storage by adding a hardenable binding agent to a container filled with the waste under a partial vacuum. The improved homogeneity of mixing of the binder and waste is enhanced by removing the partial vacuum prior to the hardening of the binder. The temperature of the container is maintained, during the addition of the binder agent to the waste, at a temperature at least equal to the melting temperature of the binder to assure thorough impregnation of the waste thereby. Preferably, the container supporting the resultant waste-binder matrix is placed in a larger container, and the space between the two containers is filled with bituminous material or concrete to provide added security against water penetration during storage.