Radionuclide sorption of Columbia River basalt interbed materials

Conference · Sat May 01 04:00:00 EDT 1982

OSTI ID:6587377

Barney, G S

Sorption and precipitation of key radionuclides in the groundwater-rock systems expected in Columbia River interbed zones were investigated. Sorption isotherms were defined for sorption of Ce, Sr, Se, Tc, Ra, U, Np, and Am on an interbed sandstone standard from the Rattlesnake Ridge interbed. In addition, the effect of groundwater composition and redox potential on sorption and precipitation of these radionuclides on interbed snadstone and tuff were studied. Isotherms were measured at 23/sup 0/, 60/sup 0/, and 85/sup 0/C. The Freundlich equation accurately fits the isotherm data when precipitation does not occur. Solubility limits were obtained for Tc and Se using the isotherms. Sorption of Cs, Se, Tc, U, and Am is strongly affected by temperature over the 23/sup 0/ to 85/sup 0/C range. The major chemical components of Grande Ronde groundwater (Na/sup +/, Ca/sup 2 +/, K/sup +/, Mg/sup 2 +/, Cl/sup -/, F/sup -/, CO/sub 3//sup 2 -/, HCO/sub 3//sup -/, and SO/sub 4//sup 2 -/) were studied for their influence on sorption and precipitation. Statistically designed experiments identified significant groundwater components and measured their effects. The results gave evidence for selecting sorption mechanisms for each radionuclide (ion exchange, chemisorption, redox reactions, complex formation, or precipitation). Strontium, Ra, and Cs are sorbed by ion exchange and compete for exchange sites with ions of similar size. The Np, Pu, and Tc are reduced by hydrazine to their (IV) oxidation states and are sorbed by chemisorption. Selenium is not reduced to the metal by hydrazine, but appears to be precipitated as a calcium compound. The groundwater variables had little effect on Am sorption. A slightly soluble Am compound appears to form which is more soluble at low pH.

• Research Organization: Rockwell International Corp., Richland, WA (USA). Rockwell Hanford Operations
• DOE Contract Number: AC06-77RL01030
• OSTI ID: 6587377
• Report Number(s): RHO-BW-SA-198-P; CONF-8205100-2; ON: DE83004200
• Country of Publication: United States
• Language: English

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54 ENVIRONMENTAL SCIENCES
ACTINIDES
ALKALINE EARTH METALS
AMERICIUM
CERIUM
COLUMBIA RIVER
ELEMENTS
ENVIRONMENTAL TRANSPORT
GROUND WATER
HYDROGEN COMPOUNDS
MASS TRANSFER
METALS
OXYGEN COMPOUNDS
PRECIPITATION
RADIOACTIVITY
RADIONUCLIDE MIGRATION
RADIUM
RARE EARTHS
RIVERS
ROCKS
SEDIMENTS
SELENIUM
SEMIMETALS
SEPARATION PROCESSES
SOLUBILITY
STREAMS
STRONTIUM
SURFACE WATERS
TECHNETIUM
TRANSITION ELEMENTS
TRANSPLUTONIUM ELEMENTS
TRANSURANIUM ELEMENTS
URANIUM
WATER