Special waste-form lysimeters - arid: 1984--1992 data summary and preliminary interpretation

Technical Report · Sat Oct 01 04:00:00 EDT 1994

DOI:https://doi.org/10.2172/10187005· OSTI ID:10187005

Jones, T L ^[1]; Serne, R J ^[2]

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1. New Mexico State Univ., Las Cruces, NM (United States)
2. Pacific Northwest Lab., Richland, WA (United States)

A lysimeter facility constructed at the Hanford Site in south-central Washington State has been used since 1984 to monitor the leaching of buried waste forms under natural conditions. The facility is generating data that are useful in evaluating source-term models used in radioactive waste transport analyses. The facility includes ten bare-soil lysimeters (183 cm diameter by 305 cm depth) containing buried waste forms generated at nuclear reactors in the United States and solidified with Portland M cement, masonry cement, bitumen, and vinyl-ester styrene. The waste forms contained in the lysimeters have been leached under natural, semiarid conditions. In spite of the semiarid conditions, from 1984 through 1992, an average of 45 cm of water leached through the lysimeters, representing 27% of area precipitation. Leachate samples have been routinely collected and analyzed for radionuclide and chemical content. To date, tritium, cobalt-60, and cesium-137 have been identified in the lysimeter leachate samples. From 1984 through 1992, over 4000 {mu}Ci of tritium, representing 76 and 71 % of inventory (not decay corrected), have been leached from the two waste forms containing tritium. Cobalt-60 has been found in the leachate from all six of the waste forms that originally contained > 1 mCi of inventory. The leached amounts of cobalt-60 represent < 0.1 % of original cobalt inventories. Mobile cobalt is believed to be chelated with organic compounds, such as ethylenediaminetetraacetic acid (EDTA), that are present in the waste. Trace amounts of cesium-137 have occasionally been identified in leachate from two waste forms since 1991. Qualitatively, the field leaching results confirm laboratory studies suggesting that tritium is readily leached from cement, and that cobalt-60 is generally leached more easily from cement than from vinyl-ester styrene.

• Research Organization: Pacific Northwest Lab., Richland, WA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 10187005
• Report Number(s): PNL--8955; ON: DE95000839
• Country of Publication: United States
• Language: English

Related Subjects

052002
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
54 ENVIRONMENTAL SCIENCES
540230
HANFORD RESERVATION
LEACHING
LYSIMETERS
MONITORING
RADIOACTIVE MATERIALS MONITORING AND TRANSPORT
RADIOACTIVE WASTE MANAGEMENT
RADIOACTIVE WASTES
RADIONUCLIDE MIGRATION
UNDERGROUND DISPOSAL
WASTE DISPOSAL AND STORAGE