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Modified approach to use of DOE-STD-3009 example risk matrices

DOE-STD-3009, Preparation Guide for US Department of Energy Non-reactor Nuclear Facilities Documented Safety Analyses, identifies a methodology for selection of high risk accidents and hazard scenarios for Hazard Category 1, 2, and 3 Nuclear Facilities and their controls. It provides examples of risk matrices which can be used as a part of this methodology. It also states, 'There is no one correct approach or presentation'. Sandia has used a modified version of these examples to focus control selection on controls that provide the highest risk to the public and the workers. Sandia's matrix assigns a lower risk level to high probability, low consequence events that are covered by institutional safety programs. The objective of this paper is to serve as a point of discussion on the benefits of using this modification to the DOE-STD-3009 examples. The paper relates to the workshop subtopic of Lessons Learned and Hazards Analysis since it provides lessons learned in hazard analysis process at SNL.

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TYPE Conference YEAR 2008
OSTI

Foam structure and rheology in thin gaps

Kraynik, Andrew M.

The cell structure and rheology of gas-liquid foams confined between parallel plates depend on the ratio H/R, where H is the plate spacing and R is the (equivalent spherical) bubble radius. We consider ordered three-dimensional foams that consist of 1-3 layers of bubbles. In the 'dry' limit, where the gas fraction is unity, one confined layer is composed of hexagonal cylinders; two layers contain Fejes Toth cells; and three or more layers are modeled as Kelvin cells sandwiched between Fejes Toth cells. We also consider wet foams where all of the liquid is assumed to be located in either conventional Plateau borders or wall Plateau borders adjacent to the plates. The Surface Evolver is used to calculate the foam structure and stress as a function of H/R, which enables us to evaluate elastic behavior. A relationship between the two-dimensional structure at the wall and bubble size has application to foam characterization.

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TYPE Conference YEAR 2008
OSTI

Object-oriented design patterns for multiphysics modeling in Fortran 2003

Rouson, Damian R.; Adalsteinsson, Helgi

The objectives of this presentation are to: catalog object-oriented software design patterns for multiphysics modeling; demonstrate them in Fortran 2003 and C++; and compare the capabilities of the two languages. The conclusions are: the presented patterns integrate multiple abstractions, allowing much of the numerics and physics to be determined at compile-time or runtime; negligible lines of Fortran emulate the required C++ features; and C++ requires considerable effort (or considerable reliance on libraries to relive that effort) to emulate the required Fortran 2003 features.

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TYPE Conference YEAR 2008
OSTI

Sandia National Laboratories California Air Quality Program Annual Report

Gardizi, Leslee P.

The annual program report provides detailed information about all aspects of the SNL/CA Air Quality Program. It functions as supporting documentation to the SNL/CA Environmental Management System Program Manual. The program report describes the activities undertaken during the past year, and activities planned in future years to implement the Air Quality Program, one of six programs that supports environmental management at SNL/CA.

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TYPE SAND Report YEAR 2008
DOIOSTI

Thermal contact algorithms in SIERRA mechanics : mathematical background, numerical verification, and evaluation of performance

Carnes, Brian R.; Copps, Kevin D.

We examine algorithms for the finite element approximation of thermal contact models. We focus on the implementation of thermal contact algorithms in SIERRA Mechanics. Following the mathematical formulation of models for tied contact and resistance contact, we present three numerical algorithms: (1) the multi-point constraint (MPC) algorithm, (2) a resistance algorithm, and (3) a new generalized algorithm. We compare and contrast both the correctness and performance of the algorithms in three test problems. We tabulate the convergence rates of global norms of the temperature solution on sequentially refined meshes. We present the results of a parameter study of the effect of contact search tolerances. We outline best practices in using the software for predictive simulations, and suggest future improvements to the implementation.

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TYPE SAND Report YEAR 2008
DOIOSTI

Issues in benchmarking human reliability analysis methods : a literature review

Hendrickson, Stacey M.; Forester, John A.

There is a diversity of human reliability analysis (HRA) methods available for use in assessing human performance within probabilistic risk assessment (PRA). Due to the significant differences in the methods, including the scope, approach, and underlying models, there is a need for an empirical comparison investigating the validity and reliability of the methods. To accomplish this empirical comparison, a benchmarking study is currently underway that compares HRA methods with each other and against operator performance in simulator studies. In order to account for as many effects as possible in the construction of this benchmarking study, a literature review was conducted, reviewing past benchmarking studies in the areas of psychology and risk assessment. A number of lessons learned through these studies are presented in order to aid in the design of future HRA benchmarking endeavors.

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TYPE SAND Report YEAR 2008
DOIOSTI
Results 78301–78400 of 99,299
Results 78301–78400 of 99,299