Patent Number: 054810612
Section: abstract

The present invention relates to a method of solidifying radioactive waste with cement, comprising forming a mixture comprising water, a hydrophilic material and cement substantially non-shrinkable or expansible with respect to volume change upon hardening, mixing said mixture with the radioactive waste, followed by hardening to form a solid body.. The present invention enables the formation of a compact solid body having voids, such as capillary voids, of reduced volume, which makes it possible to reduce the leaching rate of hazardous materials. Further, since no shrinkage accompanies hardening, no tensile stress occurs in the cement surrounding minute waste particles within the hardened material, thereby enabling a decrease in the strength of the solid body to be minimized. This in turn enables an increase in the amount of packing of waste. Prior addition of a hydrophilic material enables the cement fluidity before hardening to be maintained even after complete absorption of water by a water absorptive waste. This is extremely advantageous in carrying out hardening.