Solidification method for incinerated ash

The present invention concerns a solidification method for radioactive incinerated ashes generated from a nuclear power plant. The burnt ashes are at first supplied to a crushing and screening device, to be sieved into lumps (lumps of metals and not pulverized ashes having a hardness more than a predetermined level) and powders. Powders are granulated into pellets having a hardness and a strength each of more than a predetermined level. The lumps and the pellets are charged to a solidification container and solidified by grouting solidifying material. When the solidifying material is grouted, since there is no powder in the space between the lumps and the pellets, the solidifying material can prevail sufficiently, causing no harmful gaps. Further, since lumps of ashes having a hardness less than a predetermined level are crushed and then granulated into pellets having a hardness and a strength each of more than the predetermined level, the strength of the solidification products can also be maintained. Then, homogeneous solidification products having sufficient strength with no harmful gaps can be manufactured. (I.N.)