Optimization of the factors that accelerate leaching

Technical Report · Wed Mar 01 04:00:00 EST 1989

DOI:https://doi.org/10.2172/5624066· OSTI ID:5624066

Fuhrmann, M; Pietrzak, R F; Franz, E M; Heiser, III, J H; Colombo, P

The prediction of long-term leachability of low-level radioactive waste forms is an essential element of disposal-site performance assessment. This report describes experiments and modeling techniques used to develop an accelerated leach test that meets this need. The acceleration in leaching rates caused by the combinations of two or more factors were experimentally determined. These factors were identified earlier as being able to individually accelerate leaching. They are: elevated temperature, the size of the waste form, the ratio of the volume of leachant to the surface area of the waste form, and the frequency of replacement of the leachant. The solidification agents employed were ones that are currently used to treat low-level radioactive wastes, namely portland type I cement, bitumen, and vinyl ester-styrene. The simulated wastes, sodium sulfate, sodium tetraborate, and incinerator ash, are simplified representatives of typical low-level waste streams. Experiments determined the leaching behavior of the radionuclides of cesium (Cs-137), strontium (Sr-85), and cobalt (Co-60 or Co-57) from several different formulations of solidification agents and waste types. Leaching results were based upon radiochemical and elemental analyses of aliquots of the leachate, and on its total alkalinity and pH at various times during the experiment (up to 120 days). Solid phase analyses were carried out by Scanning/Electron Microscopy and Energy Dispersive Spectroscopy on the waste forms before and after some leaching experiments. 43 refs., 96 figs., 16 tabs.

• Research Organization: Brookhaven National Lab., Upton, NY (USA)
• Sponsoring Organization: DOE/NE
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 5624066
• Report Number(s): BNL-52204; ON: DE90000886
• Country of Publication: United States
• Language: English

Related Subjects

052002* -- Nuclear Fuels-- Waste Disposal & Storage
053000 -- Nuclear Fuels-- Environmental Aspects
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
ALKALI METAL ISOTOPES
ALKALINE EARTH ISOTOPES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BUILDING MATERIALS
CEMENTS
CESIUM 137
CESIUM ISOTOPES
COBALT 57
COBALT 60
COBALT ISOTOPES
DAYS LIVING RADIOISOTOPES
DISSOLUTION
ELECTRON CAPTURE RADIOISOTOPES
ENVIRONMENTAL IMPACTS
EVEN-ODD NUCLEI
GROUND DISPOSAL
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LEACHING
LIQUID WASTES
LOW-LEVEL RADIOACTIVE WASTES
MANAGEMENT
MATERIALS
MATHEMATICAL MODELS
MINUTES LIVING RADIOISOTOPES
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
PHASE TRANSFORMATIONS
RADIOACTIVE MATERIALS
RADIOACTIVE WASTES
RADIOISOTOPES
SEPARATION PROCESSES
SOLIDIFICATION
STRONTIUM 85
STRONTIUM ISOTOPES
WASTE DISPOSAL
WASTE FORMS
WASTE MANAGEMENT
WASTES
YEARS LIVING RADIOISOT
YEARS LIVING RADIOISOTOPES