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Illustration of sampling-based approaches to the calculation of expected dose in performance assessments for the proposed high level radioactive waste repository at Yucca Mountain, Nevada.

Description: A deep geologic repository for high level radioactive waste is under development by the U.S. Department of Energy at Yucca Mountain (YM), Nevada. As mandated in the Energy Policy Act of 1992, the U.S. Environmental Protection Agency (EPA) has promulgated public health and safety standards (i.e., 40 CFR Part 197) for the YM repository, and the U.S. Nuclear Regulatory Commission has promulgated licensing standards (i.e., 10 CFR Parts 2, 19, 20, etc.) consistent with 40 CFR Part 197 that the DOE m… more
Date: April 1, 2007
Creator: Helton, Jon Craig & Sallaberry, Cedric J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Multiple predictor smoothing methods for sensitivity analysis.

Description: The use of multiple predictor smoothing methods in sampling-based sensitivity analyses of complex models is investigated. Specifically, sensitivity analysis procedures based on smoothing methods employing the stepwise application of the following nonparametric regression techniques are described: (1) locally weighted regression (LOESS), (2) additive models, (3) projection pursuit regression, and (4) recursive partitioning regression. The indicated procedures are illustrated with both simple tes… more
Date: August 1, 2006
Creator: Helton, Jon Craig & Storlie, Curtis B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Guest editorial: The 1996 performance assessment for the Waste Isolation Pilot Plant

Description: The appropriate disposal of radioactive waste is a problem of great importance, wide-spread interest, and some controversy. As part of the solution to this problem the Waste Isolation Pilot Plant (WIPP) is under development by the US Department of Energy (DOE) for the deep geologic disposal of transuranic (TRU) waste generated by defense programs in the United States. The DOE submitted a Compliance Certification Application (CCA){sup 17} for the WIPP to the US Environmental Protection Agency (E… more
Date: May 19, 2000
Creator: HELTON,JON CRAIG & MARIETTA,MELVIN G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Conceptual and computational basis for the quantification of margins and uncertainty.

Description: In 2001, the National Nuclear Security Administration of the U.S. Department of Energy in conjunction with the national security laboratories (i.e, Los Alamos National Laboratory, Lawrence Livermore National Laboratory and Sandia National Laboratories) initiated development of a process designated Quantification of Margins and Uncertainty (QMU) for the use of risk assessment methodologies in the certification of the reliability and safety of the nation's nuclear weapons stockpile. This presenta… more
Date: June 1, 2009
Creator: Helton, Jon Craig (Arizona State University, Tempe, AZ)
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Brine and Gas Flow Patterns Between Excavated Areas and Disturbed Rock Zone in the 1996 Performance Assessment for the Waste Isolation Pilot Plant for a Single Drilling Intrusion that Penetrates Repository and Castile Brine Reservoir

Description: The Waste Isolation Pilot Plant (WIPP), which is located in southeastern New Mexico, is being developed for the geologic disposal of transuranic (TRU) waste by the U.S. Department of Energy (DOE). Waste disposal will take place in panels excavated in a bedded salt formation approximately 2000 ft (610 m) below the land surface. The BRAGFLO computer program which solves a system of nonlinear partial differential equations for two-phase flow, was used to investigate brine and gas flow patterns in … more
Date: October 1, 1999
Creator: Economy, Kathleen M.; Helton, Jon Craig & Vaughn, Palmer
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Extension of latin hypercube samples with correlated variables.

Description: A procedure for extending the size of a Latin hypercube sample (LHS) with rank correlated variables is described and illustrated. The extension procedure starts with an LHS of size m and associated rank correlation matrix C and constructs a new LHS of size 2m that contains the elements of the original LHS and has a rank correlation matrix that is close to the original rank correlation matrix C. The procedure is intended for use in conjunction with uncertainty and sensitivity analysis of computa… more
Date: November 1, 2006
Creator: Hora, Stephen Curtis; Helton, Jon Craig & Sallaberry, Cedric J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Ideas underlying quantification of margins and uncertainties(QMU): a white paper.

Description: This report describes key ideas underlying the application of Quantification of Margins and Uncertainties (QMU) to nuclear weapons stockpile lifecycle decisions at Sandia National Laboratories. While QMU is a broad process and methodology for generating critical technical information to be used in stockpile management, this paper emphasizes one component, which is information produced by computational modeling and simulation. In particular, we discuss the key principles of developing QMU inform… more
Date: September 1, 2006
Creator: Helton, Jon Craig; Trucano, Timothy Guy & Pilch, Martin M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Characterization of stochastic uncertainty in the 1996 performance assessment for the Waste Isolation Pilot Plant

Description: The 1996 performance assessment (PA) for the Waste Isolation Pilot Plant (WIPP) maintains a separation between stochastic (i.e., aleatory) and subjective (i.e., epistemic) uncertainty, with stochastic uncertainty arising from the possible disruptions that could occur at the WIPP over the 10,000 yr regulatory period specified by the US Environmental Protection Agency (40 CFR 191, 40 CFR 194) and subjective uncertainty arising from an inability to uniquely characterize many of the inputs required… more
Date: May 19, 2000
Creator: Helton, Jon Craig; Davis, Freddie J. & Johnson, J. D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Characterization of subjective uncertainty in the 1996 performance assessment for the Waste Isolation Pilot Plant

Description: The 1996 performance assessment (PA) for the Waste Isolation Pilot Plant (WIPP) maintains a separation between stochastic (i.e., aleatory) and subjective (i.e., epistemic) uncertainty, with stochastic uncertainty arising from the possible disruptions that could occur at the WIPP over the 10,000 yr regulatory period specified by the US Environmental Protection Agency (40 CFR 191,40 CFR 194) and subjective uncertainty arising from an inability to uniquely characterize many of the inputs required … more
Date: May 18, 2000
Creator: HELTON,JON CRAIG; MARTELL,MARY-ALENA & TIERNEY,MARTIN S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Probability of loss of assured safety in systems with multiple time-dependent failure modes.

Description: Weak link (WL)/strong link (SL) systems are important parts of the overall operational design of high-consequence systems. In such designs, the SL system is very robust and is intended to permit operation of the entire system under, and only under, intended conditions. In contrast, the WL system is intended to fail in a predictable and irreversible manner under accident conditions and render the entire system inoperable before an accidental operation of the SL system. The likelihood that the WL… more
Date: September 1, 2012
Creator: Helton, Jon Craig; Pilch, Martin M. & Sallaberry, Cedric M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Development, analysis, and evaluation of a commercial software framework for the study of Extremely Low Probability of Rupture (xLPR) events at nuclear power plants.

Description: Sandia National Laboratories (SNL) participated in a Pilot Study to examine the process and requirements to create a software system to assess the extremely low probability of pipe rupture (xLPR) in nuclear power plants. This project was tasked to develop a prototype xLPR model leveraging existing fracture mechanics models and codes coupled with a commercial software framework to determine the framework, model, and architecture requirements appropriate for building a modular-based code. The xLP… more
Date: December 1, 2010
Creator: Kalinich, Donald A.; Helton, Jon Craig; Sallaberry, Cedric M. & Mattie, Patrick D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A sampling-based computational strategy for the representation of epistemic uncertainty in model predictions with evidence theory.

Description: Evidence theory provides an alternative to probability theory for the representation of epistemic uncertainty in model predictions that derives from epistemic uncertainty in model inputs, where the descriptor epistemic is used to indicate uncertainty that derives from a lack of knowledge with respect to the appropriate values to use for various inputs to the model. The potential benefit, and hence appeal, of evidence theory is that it allows a less restrictive specification of uncertainty than … more
Date: October 1, 2006
Creator: Johnson, J. D.; Oberkampf, William Louis; Helton, Jon Craig & Storlie, Curtis B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Survey of sampling-based methods for uncertainty and sensitivity analysis.

Description: Sampling-based methods for uncertainty and sensitivity analysis are reviewed. The following topics are considered: (1) Definition of probability distributions to characterize epistemic uncertainty in analysis inputs, (2) Generation of samples from uncertain analysis inputs, (3) Propagation of sampled inputs through an analysis, (4) Presentation of uncertainty analysis results, and (5) Determination of sensitivity analysis results. Special attention is given to the determination of sensitivity a… more
Date: June 1, 2006
Creator: Johnson, Jay Dean; Helton, Jon Craig; Sallaberry, Cedric J. & Storlie, Curt B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Conceptual structure of the 1996 performance assessment for the Waste Isolation Pilot Plant

Description: The conceptual structure of the 1996 performance assessment (PA) for the Waste Isolation Pilot Plant (WIPP) is described. This structure involves three basic entities (EN1, EN2, EN3): (1) EN1, a probabilistic characterization of the likelihood of different futures occurring at the WIPP site over the next 10,000 yr, (2) EN2, a procedure for estimating the radionuclide releases to the accessible environment associated with each of the possible futures that could occur at the WIPP site over the ne… more
Date: May 18, 2000
Creator: HELTON,JON CRAIG; ANDERSON,D. RICHARD; BASABILVAZO,G.; JOW,HONG-NIAN & MARIETTA,MELVIN G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Summary discussion of the 1996 performance assessment for the Waste Isolation Pilot Plant

Description: The Waste Isolation Pilot Plant (WIPP) is under development by the US Department of Energy (DOE) for the geologic disposal of transuranic waste. The construction of complementary cumulative distribution functions (CCDFs) for total radionuclide release from the WIPP to the accessible environment is described. The resultant CCDFs (1) combine releases due to cuttings and cavings, spallings, direct brine release, and long-term transport in flowing groundwater, (2) fall substantially to the left of … more
Date: May 19, 2000
Creator: HELTON,JON CRAIG; ANDERSON,D. RICHARD; BASABILVAZO,G.; JOW,HONG-NIAN & MARIETTA,MELVIN G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Probability of loss of assured safety in temperature dependent systems with multiple weak and strong links.

Description: Relationships to determine the probability that a weak link (WL)/strong link (SL) safety system will fail to function as intended in a fire environment are investigated. In the systems under study, failure of the WL system before failure of the SL system is intended to render the overall system inoperational and thus prevent the possible occurrence of accidents with potentially serious consequences. Formal developments of the probability that the WL system fails to deactivate the overall system… more
Date: December 1, 2004
Creator: Johnson, Jay Dean (ProStat, Mesa, AZ); Oberkampf, William Louis & Helton, Jon Craig (Arizona State University, Tempe, AZ)
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Effect of delayed link failure on probability of loss of assured safety in temperature-dependent systems with multiple weak and strong links.

Description: Weak link (WL)/strong link (SL) systems constitute important parts of the overall operational design of high consequence systems, with the SL system designed to permit operation of the system only under intended conditions and the WL system designed to prevent the unintended operation of the system under accident conditions. Degradation of the system under accident conditions into a state in which the WLs have not deactivated the system and the SLs have failed in the sense that they are in a co… more
Date: May 1, 2007
Creator: Johnson, J. D. (ProStat, Mesa, AZ); Oberkampf, William Louis & Helton, Jon Craig (Arizona State University, Tempe, AZ)
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Verification test problems for the calculation of probability of loss of assured safety in temperature-dependent systems with multiple weak and strong links.

Description: Four verification test problems are presented for checking the conceptual development and computational implementation of calculations to determine the probability of loss of assured safety (PLOAS) in temperature-dependent systems with multiple weak links (WLs) and strong links (SLs). The problems are designed to test results obtained with the following definitions of loss of assured safety: (1) Failure of all SLs before failure of any WL, (2) Failure of any SL before failure of any WL, (3) Fai… more
Date: June 1, 2006
Creator: Johnson, Jay Dean (ProStat, Mesa, AZ); Oberkampf, William Louis & Helton, Jon Craig (Arizona State University, Tempe, AZ)
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Representation of two-phase flow in the vicinity of the repository in the 1996 performance assessment for the Waste Isolation Pilot Plant

Description: The following topics related to the representation of two-phase (gas and brine) flow in the vicinity of the repository in the 1996 performance assessment (PA) for the Waste Isolation Pilot Plant (WIPP) are discussed: (1) system of nonlinear partial differential equations used to model two-phase flow, (2) incorporation of repository shafts into model (3) creep closure of repository. (4) interbed fracturing, (5) gas generation (6) capillary action in waste, (7) borebole model (8) numerical soluti… more
Date: May 18, 2000
Creator: Vaughn, Palmer; Bean, J. E.; Helton, Jon Craig; Lord, Michael E.; Mackinnon, Robert J. & Schreiber, James D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Radionuclide transport in the vicinity of the repository and associated complementary cumulative distribution functions in the 1996 performance assessment for the Waste Isolation Pilot Plant

Description: The following topics related to radionuclide transport in the vicinity of the repository in the 1996 performance assessment for the Waste Isolation Pilot Plant are presented (1) mathematical description of models, (2) uncertainty and sensitivity analysis results arising from subjective (i.e., epistemic) uncertainty for individual releases, (3) construction of complementary cumulative distribution functions (CCDFs) arising from stochastic (i.e., aleatory) uncertainty, and (4) uncertainty and sen… more
Date: May 22, 2000
Creator: Stockman, Christine T.; Garner, J. W.; Helton, Jon Craig; Johnson, Jay Dean; Shinta, A. & Smith, L. N.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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