Sensitivity and uncertainty analyses applied to one-dimensional radionuclide transport in a layered fractured rock: Evaluation of the Limit State approach, Iterative Performance Assessment, Phase 2

Technical Report · Tue Dec 01 00:00:00 EST 1992

DOI:https://doi.org/10.2172/6812660· OSTI ID:6812660

Wu, Y T; Gureghian, A B; Sagar, B ^[1]; Codell, R B ^[2]

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1. Southwest Research Inst., San Antonio, TX (United States). Center for Nuclear Waste Regulatory Analyses
2. Nuclear Regulatory Commission, Washington, DC (United States). Div. of High-Level Waste Management

The Limit State approach is based on partitioning the parameter space into two parts: one in which the performance measure is smaller than a chosen value (called the limit state), and the other in which it is larger. Through a Taylor expansion at a suitable point, the partitioning surface (called the limit state surface) is approximated as either a linear or quadratic function. The success and efficiency of the limit state method depends upon choosing an optimum point for the Taylor expansion. The point in the parameter space that has the highest probability of producing the value chosen as the limit state is optimal for expansion. When the parameter space is transformed into a standard Gaussian space, the optimal expansion point, known as the lost Probable Point (MPP), has the property that its location on the Limit State surface is closest to the origin. Additionally, the projections onto the parameter axes of the vector from the origin to the MPP are the sensitivity coefficients. Once the MPP is determined and the Limit State surface approximated, formulas (see Equations 4-7 and 4-8) are available for determining the probability of the performance measure being less than the limit state. By choosing a succession of limit states, the entire cumulative distribution of the performance measure can be detemined. Methods for determining the MPP and also for improving the estimate of the probability are discussed in this report.

• Research Organization: Nuclear Regulatory Commission, Washington, DC (United States). Div. of High-Level Waste Management; Southwest Research Inst., San Antonio, TX (United States). Center for Nuclear Waste Regulatory Analyses
• Sponsoring Organization: USNRC; Nuclear Regulatory Commission, Washington, DC (United States)
• OSTI ID: 6812660
• Report Number(s): NUREG/CR-5917-Vol.2; CNWRA-92-002-Vol.2; ON: TI93006315
• Country of Publication: United States
• Language: English

Related Subjects

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
54 ENVIRONMENTAL SCIENCES
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
FRACTURED RESERVOIRS
RADIONUCLIDE MIGRATION
RADIOACTIVE WASTE DISPOSAL
MATHEMATICAL MODELS
ROCKS
DATA COVARIANCES
LAYERS
MONTE CARLO METHOD
PERFORMANCE
PROBABILITY
SENSITIVITY ANALYSIS
CALCULATION METHODS
ENVIRONMENTAL TRANSPORT
MANAGEMENT
MASS TRANSFER
RADIOACTIVE WASTE MANAGEMENT
WASTE DISPOSAL
WASTE MANAGEMENT
052002* - Nuclear Fuels- Waste Disposal & Storage
540230 - Environment
Terrestrial- Radioactive Materials Monitoring & Transport- (1990-)
990200 - Mathematics & Computers