Leaching of fully radioactive high-level waste glass

Technical Report · Fri Sep 01 04:00:00 EDT 1978

DOI:https://doi.org/10.2172/6824618· OSTI ID:6824618

Bradley, D J

As part of continuing Department of Energy (DOE)-sponsored studies in waste management, the Pacific Northwest Laboratory (PNL) has been conducting the High-Level Waste Immobilization Program. The purpose of this program is to develop and demonstrate technology for incorporating nuclear wastes into final waste forms. The preparation and leach testing of fully radioactive, zinc borosilicate glass, which was prepared from power reactor waste, are described. Leach testing using the International Atomic Energy Association (IAEA) procedure was performed in deionized water for a period of 1.75 years. Leach rates were determined for activation products, fission products, and actinides. These rates ranged from 4 x 10/sup -5/ g of glass/cm/sup 2/-day, based on cesium, to 4 x 10/sup -9/ g of glass/cm/sup 2/-day, based on cerium. Following is the ranking of the release rates of the elements, from highest to lowest: Cs > Sr > Co > Sb > Mn > Pu > Eu > Rh > Cm > Ce. A similar leach test, using the same glass composition but with nonradioactive elements, has recently been completed. The leach rates of Cs and Sr for the nonradioactive glass were found to be in close agreement with those in this study. Slopes calculated from curves of cumulative fractions leached show that radioisotope release begins with a diffusion-type mechanism and changes gradually to a silicate lattice alteration mechanism. Changes in sampling frequency altered the apparent release mechanism when leachant changes were longer than one month. The leach rates were quite constant for samples taken from the top to the bottom of the glass melt, indicating a homogeneous product. Safety assessment studies and modeling programs use leach rates to predict the amount of radioactive material released should the waste be contacted by aqueous solutions. Further tests, focusing on geologic storage conditions and using fully radioactive wastes, are planned.

• Research Organization: Battelle Pacific Northwest Labs., Richland, WA (USA)
• DOE Contract Number: EY-76-C-06-1830
• OSTI ID: 6824618
• Report Number(s): PNL-2664
• Country of Publication: United States
• Language: English

Related Subjects

052001* -- Nuclear Fuels-- Waste Processing
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
ACTINIDES
ALKALI METALS
ALKALINE EARTH METALS
ANTIMONY
BORON COMPOUNDS
BOROSILICATES
CERIUM
CESIUM
COBALT
CURIUM
DISSOLUTION
ELEMENTS
EUROPIUM
HIGH-LEVEL RADIOACTIVE WASTES
LEACHING
MANAGEMENT
MANGANESE
METALS
PHASE TRANSFORMATIONS
PLATINUM METALS
PLUTONIUM
PROCESSING
RADIOACTIVE MATERIALS
RADIOACTIVE WASTE PROCESSING
RADIOACTIVE WASTES
RARE EARTHS
REFRACTORY METALS
RHODIUM
SEPARATION PROCESSES
SILICON COMPOUNDS
SOLIDIFICATION
STRONTIUM
TRANSITION ELEMENTS
TRANSPLUTONIUM ELEMENTS
TRANSURANIUM ELEMENTS
WASTE MANAGEMENT
WASTE PROCESSING
WASTES