Oxidation-induced geochemical changes in trench leachates from the Maxey Flats low-level radioactive waste disposal site
A knowledge of extra-trench processes related to oxidation-induced geochemical changes that are likely to occur when iron-rich, anoxic trench waters encounter an oxidizing environment along a redox gradient is essential for modeling radionuclide transport at low-level waste (LLW) disposal sites. The results of laboratory oxidation experiments on several trench leachates from the Maxey Flats site show that, upon oxidation, a series of geochemical changes were initiated that resulted in a drastically different solute geochemistry, involving oxidation of ferrous iron and subsequent precipitation of ferric oxyhydroxide, changes in alkalinity and acidity, a drastic increase in redox potential (Eh), and generally relatively little change in the concentrations of /sup 60/Co, /sup 137/Cs, and /sup 85/Sr in solution. The observations made in this study have important geochemical implications for the modeling of LLW sites in that the source term as an input parameter cannot be assumed to be constant, both spatially and temporally. The acid-generating potential and buffering capacity of an anoxic source term are important geochemical controls that maintain a balance between acidity and alkalinity and largely determine the nature and extent of oxidation-induced geochemical changes likely to occur along a redox gradient. The presence of organic chelating agents can alter the source term geochemistry to such an extent that authigenic ferric oxyhydroxide, which represents a geochemical discontinuity at the redox interface along leachate migration paths, proves to be a relatively ineffective sink for radionuclides.
- Research Organization:
- Brookhaven National Lab., Dept. of Nuclear Energy, Upton, NY 11973
- OSTI ID:
- 6077766
- Journal Information:
- Nucl. Technol.; (United States), Vol. 72:2
- Country of Publication:
- United States
- Language:
- English
Similar Records
Evaluation of isotope migration: land burial. Water chemistry at commercially operated low-level radioactive waste disposal sites. Quarterly progress report, April-June 1981
Source term characterization for the Maxey Flats low-level radioactive waste disposal site
Related Subjects
54 ENVIRONMENTAL SCIENCES
CESIUM 137
RADIOECOLOGICAL CONCENTRATION
COBALT 60
GROUND WATER
RADIONUCLIDE MIGRATION
LOW-LEVEL RADIOACTIVE WASTES
UNDERGROUND DISPOSAL
RADIOACTIVE WASTE DISPOSAL
SOURCE TERMS
STRONTIUM 85
ACID NEUTRALIZING CAPACITY
ANOXIA
GEOCHEMISTRY
LEACHATES
OXIDATION
PH VALUE
RADIOACTIVE WASTE FACILITIES
REDOX REACTIONS
ALKALI METAL ISOTOPES
ALKALINE EARTH ISOTOPES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CESIUM ISOTOPES
CHEMICAL REACTIONS
CHEMISTRY
COBALT ISOTOPES
DAYS LIVING RADIOISOTOPES
DISPERSIONS
ECOLOGICAL CONCENTRATION
ELECTRON CAPTURE RADIOISOTOPES
ENVIRONMENTAL TRANSPORT
EVEN-ODD NUCLEI
HOURS LIVING RADIOISOTOPES
HYDROGEN COMPOUNDS
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MANAGEMENT
MASS TRANSFER
MATERIALS
MINUTES LIVING RADIOISOTOPES
MIXTURES
NUCLEAR FACILITIES
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
OXYGEN COMPOUNDS
RADIOACTIVE MATERIALS
RADIOACTIVE WASTES
RADIOISOTOPES
SOLUTIONS
STRONTIUM ISOTOPES
WASTE DISPOSAL
WASTE MANAGEMENT
WASTES
WATER
WATER CHEMISTRY
YEARS LIVING RADIOISOTOPES
052002* - Nuclear Fuels- Waste Disposal & Storage
520301 - Environment
Aquatic- Radioactive Materials Monitoring & Transport- Water- (1987)