Ocean floor sediment as a repository barrier: comparative diffusion data for selected radionuclides in sediments from the Atlantic and Pacific Oceans

Conference · Wed Jan 01 04:00:00 EST 1986 · Mater. Res. Soc. Symp. Proc.; (United States)

OSTI ID:5366650

Schreiner, F; Sabau, C; Friedman, A; Fried, S

Effective diffusion coefficients for selected radionuclides have been measured in ocean floor sediments to provide data for the assessment of barrier effectiveness in subseabed repositories for nuclear waste. The sediments tested include illite-rich and smectite-rich red clays from the mid plate gyre region of the Pacific Ocean, reducing sediment from the continental shelf of the northwest coast of North America, and Atlantic Ocean sediments from the Southern Nares Abyssal Plain and the Great Meteor East region. Results show extremely small effective diffusion coefficients with values less than 10/sup -14/ m/sup 2/s/sup -1/ for plutonium, americium, curium, thorium, and tin. Radionuclides with high diffusion coefficients of approximately 10/sup -10/ m/sup 2/s/sup -/ include the anionic species pertechnetate, TcO/sub 4//sup -/, iodide, I/sup -/, and selenite, SO/sub 3//sup -2/. Uranyl(VI) and neptunyl(V) ions, which are stable in solution, have diffusion coefficients around 10/sup -12/m/sup 2/s/sup -1/. The diffusion behavior of most radionuclides is similar in the oxygenated Pacific sediments and in the anoxic sediments from the Atlantic. An exception is neptunium, which is immobilized by Great Meteor East sediment, but has high mobility in Southern Nares Abyssal Plain sediment. Under stagnant conditions a 30 m thick sediment layer forms an effective geologic barrier isolating radionuclides in a subseabed repository from the biosphere.

• Research Organization: Argonne National Lab., IL
• OSTI ID: 5366650
• Report Number(s): CONF-850995-
• Conference Information: Journal Name: Mater. Res. Soc. Symp. Proc.; (United States) Journal Volume: 50
• Country of Publication: United States
• Language: English

Related Subjects

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Aquatic-- Radioactive Materials Monitoring & Transport-- Water-- (1987)
54 ENVIRONMENTAL SCIENCES
ACTINIDE COMPOUNDS
ACTINIDES
AMERICIUM
CLAYS
CURIUM
DIFFUSION
ELEMENTS
ENVIRONMENTAL TRANSPORT
HALIDES
HALOGEN COMPOUNDS
IODIDES
IODINE COMPOUNDS
MANAGEMENT
MARINE DISPOSAL
MASS TRANSFER
METALS
NEPTUNIUM COMPOUNDS
NEPTUNYL COMPOUNDS
OXYGEN COMPOUNDS
PERTECHNETATES
PLUTONIUM
RADIOACTIVE WASTE DISPOSAL
RADIONUCLIDE MIGRATION
REFRACTORY METAL COMPOUNDS
SEA BED
SEDIMENTS
SELENITES
SELENIUM COMPOUNDS
TECHNETIUM COMPOUNDS
THORIUM
TIN
TRANSITION ELEMENT COMPOUNDS
TRANSPLUTONIUM ELEMENTS
TRANSURANIUM COMPOUNDS
TRANSURANIUM ELEMENTS
URANIUM COMPOUNDS
URANYL COMPOUNDS
WASTE DISPOSAL
WASTE MANAGEMENT