Summary of Uranium Solubility Studies in Concrete Waste Forms and Vadose Zone Environments

Golovich, Elizabeth C. ; Wellman, Dawn M. ; Serne, R. Jeffrey ; Bovaird, Chase C.

关键词: AR FACILITIES;    CLOSURES;    CONCRETES;    DIMENSIONS;    ENVIRONMENTAL EXPOSURE;    LOW-LEVEL RADIOACTIVE WASTES;    PRECIPITATION;    RADIOISOTOPES;    SOILS;    SOLUBILITY;    THICKNESS;    URANIUM;    URANIUM MINERALS;    WASTE FORMS;    WASTES;    WATER INFLUX;   

DOI  :  10.2172/1028569
RP-ID  :  PNNL-20726
PID  :  OSTI ID: 1028569
Others  :  Other: 830403000
Others  :  TRN: US1106018

学科分类：核能源与工程

美国|英语

来源: SciTech Connect

【 摘 要 】

One of the methods being considered for safely disposing of Category 3 low-level radioactive wastes is to encase the waste in concrete. Concrete encasement would contain and isolate the waste packages from the hydrologic environment and act as an intrusion barrier. The current plan for waste isolation consists of stacking low-level waste packages on a trench floor, surrounding the stacks with reinforced steel, and encasing these packages in concrete. These concrete-encased waste stacks are expected to vary in size with maximum dimensions of 6.4 m long, 2.7 m wide, and 4 m high. The waste stacks are expected to have a surrounding minimum thickness of 15 cm of concrete encasement. These concrete-encased waste packages are expected to withstand environmental exposure (solar radiation, temperature variations, and precipitation) until an interim soil cover or permanent closure cover is installed and to remain largely intact thereafter. Any failure of concrete encasement may result in water intrusion and consequent mobilization of radionuclides from the waste packages. This report presents the results of investigations elucidating the uranium mineral phases controlling the long-term fate of uranium within concrete waste forms and the solubility of these phases in concrete pore waters and alkaline, circum-neutral vadose zone environments.