Method of volume-decreasing solidification for radioactive ashes

Purpose: To convert radioactive wastes burnt ashes containing impurities such as metals, ceramics or crud into stable solid products without scattering of pollutions, as well as to decrease the volume. Method: Burnt ashes containing impurities or crud are filled in a container with an opening and closely sealed with or without evacuating the inside of the container. Thereafter, hot hydrostatic pressing is applied to the container under a gaseous atmosphere at high temperature and high pressure to thereby sinter the ashes or crud with impurities into compacted and integrated sintered products. Since the burnt ashes are also filled between each of the miscellaneous impurities, whereby final stable products become extremely compact solid. (Kawakami, Y.)