Sorption and desorption reactions of radionuclides with a crushed basalt-bentonite packing material

Conference · Mon Apr 01 04:00:00 EST 1985

OSTI ID:5243652

Barney, G S; Lane, D L; Allen, C C; Jones, T E

Current design of waste packages for disposal of high-level radioactive wastes in underground basalt formations includes a layer of packing material that surrounds the waste container. One of the functions of this material is to limit the release of radionuclides from a breached container into groundwater by providing a low hydraulic conductivity zone and by sorbing dissolved radionuclides. The objective of this study was to assess the radionuclide sorption capability of a proposed packing material composed of 25% sodium bentonite and 75% crushed basalt (by weight). Sorption and desorption reactions of several important waste radioelements (neptunium, uranium, plutonium, technetium, selenium, and radium) were investigated in the absence of air at 90/sup 0/C. Uranium and neptunium were sorbed by slow reactions that follow first-order kinetics. The reaction rates are probably controlled by reduction of weakly sorbed uranium(VI) and neptunium(V) by ferrous iron in the crushed basalt component. Technetium(VII) was not reduced or sorbed under these conditions. Freundlich sorption and desorption isotherms for a given radionuclide were non-singular and show a strong tendency for sorption hysteresis. Applying the isotherm data to a one-dimensional transport model indicated that hysteretic sorption on the packing material provides an important safety factor in controlling releases of some radionuclides.

• Research Organization: Rockwell International Corp., Richland, WA (USA). Rockwell Hanford Operations
• DOE Contract Number: AC06-77RL01030
• OSTI ID: 5243652
• Report Number(s): RHO-BW-SA-416-P; CONF-850417-32; ON: DE86015574
• Country of Publication: United States
• Language: English

Related Subjects

052002 -- Nuclear Fuels-- Waste Disposal & Storage
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
36 MATERIALS SCIENCE
360603* -- Materials-- Properties
ACTINIDES
ALKALINE EARTH METALS
BASALT
BENTONITE
CHEMICAL REACTION KINETICS
CLAYS
DATA
DESORPTION
ELEMENTS
EXPERIMENTAL DATA
GROUND WATER
HYDROGEN COMPOUNDS
IGNEOUS ROCKS
INFORMATION
ISOTHERMS
KINETICS
MATERIALS TESTING
METALS
NEPTUNIUM
NUMERICAL DATA
OXYGEN COMPOUNDS
PACKAGING
PLUTONIUM
RADIUM
REACTION KINETICS
ROCKS
SELENIUM
SEMIMETALS
SORPTION
SORPTIVE PROPERTIES
SURFACE PROPERTIES
TECHNETIUM
TESTING
TRANSITION ELEMENTS
TRANSURANIUM ELEMENTS
URANIUM
VOLCANIC ROCKS
WATER