Low sintering temperature glass waste forms for sequestering radioactive iodine

An iodine-loaded waste form, comprising a glassy body comprised of a mixture of a LST (Low-Sintering-Temperature) glass and an iodine-loaded material;

• wherein the LST glass comprises 51-55 wt % Bi, 21-22 wt % Zn, and 3-4 wt % B, with the remainder comprising O, and comprising essentially no lead or silicon;
• wherein the LST glass has a sintering temperature of about 500° C.;
• wherein the iodine-loaded material comprises AgI-zeolite;
• and
• wherein the zeolite comprises Mordenite zeolite.

A method of forming a glassy iodine-loaded waste form, comprising:

• a) mixing powdered frits of a LST (Low-Sintering-Temperature) glass with particles or powders of an iodine-loaded material, wherein the LST glass comprises bismuth oxide and at least one element selected from the group consisting of oxides of Pb, Bi, Zn and B;
• and wherein the iodine-loaded material is selected from the group consisting of AgI, AgI-zeolite, Ag-silica aerogel, ZnI2, CuI, and a bismuth-oxy-iodine compound having a thermal decomposition temperature greater than the sintering temperature of the LST glass.
• b) heating the mixture in an oxidizing environment at a temperature that ranges from 425° C. to 550° C., which sinters and densifies the mixture;
• and then
• c) cooling the sintered mixture.