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Interactions of /sup 57/Co, /sup 85/Sr and /sup 137/Cs with peat under acidic precipitation conditions

Journal Article · · Health Phys.; (United States)

Following the burial of low-level wastes in nuclear waste repositories, the interactions of radionuclides with surrounding soil infiltrated by acid precipitation could cause radionuclide migration and transport into nearby wells. To evaluate this migration through organically rich soil in the unsaturated zone, we measured sorption and desorption distribution ratios (Rd) of /sup 57/Co, /sup 85/Sr and /sup 137/Cs onto peat at pH 4. Peat samples rich in organic C showed relatively higher sorption Rd values for /sup 57/Co and /sup 85/Sr compared to soil samples with less organic C. The sorption and desorption Rd values for these radionuclides are similar, indicating the reversibility of the sorption process. The measurements suggest the importance of organic complexes for the retention of these radionuclides at the pH range (pH 4), where hydrolysis of the metals is not important and sorption is expected to be low. Cesium-137, on the other hand, appears to be associated more strongly with inorganic components of the soil samples, with its Rd value significantly higher in the peat material containing less organic C. The /sup 137/Cs desorption Rd on the same peat sample is also comparable to the sorption Rd indicating equilibrium. Both the organic and inorganic components of peat are thus able to retard the migration of radionuclides which may be found in nuclear waste repositories. The design of such a repository may be improved using a peat barrier to restrict radionuclide migration.

Research Organization:
Univ. of Pittsburgh, PA (USA)
OSTI ID:
5229598
Journal Information:
Health Phys.; (United States), Journal Name: Health Phys.; (United States) Vol. 54:3; ISSN HLTPA
Country of Publication:
United States
Language:
English