High level waste immobilization forms

Abstract

ABSTRACT. Various solid HLW forms compared for leach resistance, irradiation stability, processing, and physical properties yield alkali borosilicate glass and titanate based ceramics as leading waste forms. Titanates offer the possibility of higher waste loading. Glass waste forms offer the advantage of simpler and demonstrated full-scale and radioactive remote processing operations. Predictions of glass-repository performance based upon leaching kinetics, solubility limits, thermodynamics, and multiple films are confirmed by in situ burial tests.

Ceramics for high level radioactive waste solidification

“…The calculation of dissolution rates of NZP structure has demonstrated that it would take 20 000 times longer to dissolve NZP than quartz [21]. Work has also been reported on 3 powder and then completely mixed. The mixture was dried, prepared by thermal treatment in the temperature range of 650-1200 ℃ for 5 h. They found that the Cs or Sr immobilized material is thermally and chemically resistant, and the excellent leaching resistance is attained at 700 ℃.…”

“…Waste loadings of between 60-65 wt% have been achieved for Synroc waste forms. This corresponds to a volumetric concentration of 2.3-2.5 g/cm 3 and an equivalent Curie content of about 1.0 Ci/cm 3 . The leaching test is carried out according to the MCC-1 [29].…”

“…Although the production of Synroc is more complex than that of glass waste forms, it is generally accepted that the leach resistance of the Synroc matrix is superior to that of glass. Figure 5 shows the three major processes for preparing Synroc waste forms, the radioactive waste and Synroc additives are simply blended in a large tank, then fluidized bed calciner is used to dry the slurry, finally HIP or hot press is used to form monolithic solids [3]. Self-propagating high temperature synthesis (SHS) is a promising method to prepare Synroc waste forms [28].…”

“…Portland cement-based systems and glassed have long been identified as candidate matrices for solidification and isolation of Low-and intermediate level radioactive waste, how to deal with the high-level radioactive fission products and MA is a challenge and research focus [2,3]. In the past few decades, HLW arising from nuclear fuel reprocessing plants is immobilized in borosilicate glass.…”

Unit costs of waste management operations

“…At INEL, liquid HLW is calcined to a free-flowing granular solid (calcine) and stored in stainless-steel tanks. Most of these wastes will require incorporation into a stable, solid medium (e.g., glass) for final disposal (Hench 1984). "he total volume of HLW at the end of 1991 was 3.966 x 10 m , at a total radioactivity of 9.969 x 1 0 ' curies (Ci).…”