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

Conference · Tue Jan 01 04:00:00 EST 1985

OSTI ID:5586126

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 -1/ include the anionic species pertechnetate, TcO/sub 4//sup -/, iodide, I/sup -/, and selenite, SeO/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. 13 refs., 5 figs., 1 tab.

• Research Organization: Sandia National Labs., Albuquerque, NM (USA); Argonne National Lab., IL (USA)
• DOE Contract Number: AC04-76DP00789; W-31109-ENG-38
• OSTI ID: 5586126
• Report Number(s): CONF-850995-1; ON: DE85013859
• Country of Publication: United States
• Language: English

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54 ENVIRONMENTAL SCIENCES
ACTINIDE COMPOUNDS
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ALPHA DECAY RADIOISOTOPES
AMERICIUM 241
AMERICIUM ISOTOPES
ATLANTIC OCEAN
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CATIONS
CHARGED PARTICLES
CLAYS
CURIUM 243
CURIUM ISOTOPES
DATA
DAYS LIVING RADIOISOTOPES
DIFFUSION
ELECTRON CAPTURE RADIOISOTOPES
ENVIRONMENTAL TRANSPORT
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
HALIDES
HALOGEN COMPOUNDS
HEAVY NUCLEI
HOURS LIVING RADIOISOTOPES
INFORMATION
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IODIDES
IODINE 125
IODINE COMPOUNDS
IODINE ISOTOPES
IONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MANAGEMENT
MARINE DISPOSAL
MASS TRANSFER
MINUTES LIVING RADIOISOTOPES
NEPTUNIUM 235
NEPTUNIUM 237
NEPTUNIUM COMPOUNDS
NEPTUNIUM ISOTOPES
NEPTUNYL COMPOUNDS
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
OXYGEN COMPOUNDS
PACIFIC OCEAN
PERMEABILITY
PLUTONIUM 237
PLUTONIUM ISOTOPES
RADIOACTIVE WASTE DISPOSAL
RADIOISOTOPES
RADIONUCLIDE MIGRATION
REFRACTORY METAL COMPOUNDS
SEA BED
SEAS
SECONDS LIVING RADIOISOTOPES
SEDIMENTS
SELENITES
SELENIUM 79
SELENIUM COMPOUNDS
SELENIUM ISOTOPES
SURFACE WATERS
TECHNETATES
TECHNETIUM 99
TECHNETIUM COMPOUNDS
TECHNETIUM ISOTOPES
THORIUM 228
THORIUM ISOTOPES
TIN 113
TIN ISOTOPES
TRANSITION ELEMENT COMPOUNDS
TRANSURANIUM COMPOUNDS
URANIUM COMPOUNDS
URANYL COMPOUNDS
WASTE DISPOSAL
WASTE MANAGEMENT
YEARS LIVING RADIOISOTOPES