A convolution integral approach for performance assessments with uncertainty analysis
- Univ. of Tennessee, Knoxville, TN (United States)
Performance assessments that include uncertainty analyses and risk assessments are typically not obtained for time-dependent releases of radioactive contaminants to the geosphere when a series of sequentially coupled transport models is required for determining results. This is due, in part, to the geophysical complexity of the site, and to the numerical complexity of the fate and transport models. The lack of a practical tool for linking the transport models in a fashion that facilitates uncertainty analysis is another reason for not performing uncertainty analyses in these studies. The multiconvolution integral (MCI) approach presented herein greatly facilitates the practicality of incorporating uncertainty analyses into performance assessments. In this research an MCI approach is developed, and the decoupling of fate and transport processes into an independent system is described. A conceptual model, extracted from the Inactive Tanks project at the Oak Ridge National Laboratory (ORNL), is used to demonstrate the approach. Numerical models are used for transport of {sup 90}Sr from a disposal facility, WC-1 at ORNL, through the vadose and saturated zones to a downgradient point at Fifth Creek, and an analytical surface water model is used to transport the contaminants to a downstream potential receptor point at White Oak Creek. The probability density functions of the final concentrations obtained by the MCI approach are in excellent agreement with those obtained by a Monte Carlo approach that propagated uncertainties through all submodels for each random sample.
- OSTI ID:
- 678096
- Report Number(s):
- CONF-990605-; ISSN 0003-018X; TRN: 99:009081
- Journal Information:
- Transactions of the American Nuclear Society, Vol. 80; Conference: 1999 annual meeting of the American Nuclear Society (ANS), Boston, MA (United States), 6-10 Jun 1999; Other Information: PBD: 1999
- Country of Publication:
- United States
- Language:
- English
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