Hydrothermal simulation of ion migration in selected argillaceous sediments: implications for backfill design

Conference · Sat Jan 01 04:00:00 EST 1983 · Mater. Res. Soc. Symp. Proc.; (United States)

OSTI ID:5961974

Bratton, L; Scheetz, B E; White, W B

Argillaceous rocks, used either as a repository rock or as a backfill material provide a reactive medium with which escaped radionuclides can react. Solutions containing U, Nd, Gd, Cs, and Sr were reacted with bulk specimens of two argillites with the objective of determining penetration of heavy metals into the rock, and the reaction products. The two Devonian argillites were chosen to represent a highly reducing rock containing pyrite and carbonaceous material and accessory minerals, and a clean, alumino-silicate rock containing mainly quartz and layer silicates. Cylinders of rock were reacted with solutions at saturated steam pressures and 200/sup 0/C. At the end of the runs, both rocks contained reduced uranium in the form of UO/sub 2/ /sub 25/. The rare earths were associated with the uranium. There was a precipitated coating or uranium-rich material on the outside of the reducing shale and few of the radionuclides had penetrated the interior. Uranium also formed a precipitate within 0.5 mm of the surface of the oxidized shale leaving a depleted zone near the surface. Cesium and strontium did not penetrate the reducing shale but were uniformly distributed throughout the oxidized shale. Chlorite, apatite and pyrite were found to be the most reactive phases in the shales.

• Research Organization: Pennsylvania State Univ., University Park
• OSTI ID: 5961974
• Report Number(s): CONF-821107-Pt.1
• Conference Information: Journal Name: Mater. Res. Soc. Symp. Proc.; (United States) Journal Volume: 15
• 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
ACTINIDES
ALKALI METALS
ALKALINE EARTH METALS
ARGILLITE
BACKFILLING
CESIUM
CHEMICAL REACTIONS
DIFFUSION
ELEMENTS
ENVIRONMENTAL TRANSPORT
GADOLINIUM
MASS TRANSFER
MATERIALS TESTING
METALS
NEODYMIUM
PERMEABILITY
RADIONUCLIDE MIGRATION
RARE EARTHS
ROCKS
SEDIMENTARY ROCKS
SHALES
STRONTIUM
TESTING
URANIUM
WASTE-ROCK INTERACTIONS