Properties of a Radioactive Waste Pellet Package Using Cement-Glass

Radioactive waste slurry generated from nuclear power plants is dried and compressed into pellets. These pellets are dropped in a polymer-impregnated concrete (PIC) barrier and solidified with cement-glass, which is a mixture of sodium silicate and cement. The mechanical strength of the PIC barrier is about three times higher than that of ordinary portland cement because of added steel fibers. The leaching ratio from the package is experimentally studied using ¹⁴C, ⁶⁰Co, ⁸⁵Sr, ⁹⁹Tc, ^I25I, and ¹³⁴Cs. Because of the low porosity of the PIC barrier, the leaching rate is controlled and increases in proportion to immersion time. The maximum leaching ratio from a 200-ℓ package is estimated to be 0.004/yr.