Using High Performance Computing to Understand Roles of Labile and Nonlabile U(VI) on Hanford 300 Area Plume Longevity

Journal Article · Sat Jul 28 04:00:00 EDT 2012 · Vadose Zone Journal

DOI:https://doi.org/10.2136/vzj2011.0097· OSTI ID:1051182

Lichtner, Peter C; Hammond, Glenn E

Evolution of a hexavalent uranium [U(VI)] plume at the Hanford 300 Area bordering the Columbia River is investigated to evaluate the roles of labile and nonlabile forms of U(VI) on the longevity of the plume. A high fidelity, three-dimensional, field-scale, reactive flow and transport model is used to represent the system. Richards equation coupled to multicomponent reactive transport equations are solved for times up to 100 years taking into account rapid fluctuations in the Columbia River stage resulting in pulse releases of U(VI) into the river. The peta-scale computer code PFLOTRAN developed under a DOE SciDAC-2 project is employed in the simulations and executed on ORNL's Cray XT5 supercomputer Jaguar. Labile U(VI) is represented in the model through surface complexation reactions and its nonlabile form through dissolution of metatorbernite used as a surrogate mineral. Initial conditions are constructed corresponding to the U(VI) plume already in place to avoid uncertainties associated with the lack of historical data for the waste stream. The cumulative U(VI) flux into the river is compared for cases of equilibrium and multirate sorption models and for no sorption. The sensitivity of the U(VI) flux into the river on the initial plume configuration is investigated. The presence of nonlabile U(VI) was found to be essential in explaining the longevity of the U(VI) plume and the prolonged high U(VI) concentrations at the site exceeding the EPA MCL for uranium.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF); Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: DOE Office of Science; USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1051182
• Report Number(s): PNNL-SA-84075; KJ0403000
• Journal Information: Vadose Zone Journal, Journal Name: Vadose Zone Journal Journal Issue: 2 Vol. 11; ISSN VZJAAB; ISSN 1539-1663
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS
COLUMBIA RIVER
COMPUTER CODES
CONFIGURATION
DISSOLUTION
FLUCTUATIONS
Hanford 300 Area
PERFORMANCE
PLUMES
RIVERS
SENSITIVITY
SORPTION
SUPERCOMPUTERS
TRANSPORT
URANIUM
US EPA
WASTES
high performance computing
reactive transport