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The action characterization matrix: A link between HERA (Human Events Reference for ATHEANA) and ATHEANA (a technique for human error analysis)

The Technique for Human Error Analysis (ATHEANA) is a newly developed human reliability analysis (HRA) methodology that aims to facilitate better representation and integration of human performance into probabilistic risk assessment (PRA) modeling and quantification by analyzing risk-significant operating experience in the context of existing behavior science models. The fundamental premise of ATHEANA is that error-forcing contexts (EFCs), which refer to combinations of equipment/material condi… more

Date: December 22, 1997

Creator: Hahn, H.A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

FAST NEUTRON COVARIANCES FOR EVALUATED DATA FILES.

We describe implementation of the KALMAN code in the EMPIRE system and present first covariance data generated for Gd and Ir isotopes. A complete set of covariances, in the full energy range, was produced for the chain of 8 Gadolinium isotopes for total, elastic, capture, total inelastic (MT=4), (n,2n), (n,p) and (n,alpha) reactions. Our correlation matrices, based on combination of model calculations and experimental data, are characterized by positive mid-range and negative long-range correla… more

Date: June 5, 2006

Creator: HERMAN, M.; OBLOZINSKY, P.; ROCHMAN, D.; KAWANO, T. & LEAL, L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Overview on methods for formulating explicit damping matrices for non-classically damped structures

In computing the dynamic response of a connected system with multiple components having dissimilar damping characteristics, which is often referred to as nonclassically damped system such as nuclear power plant piping systems supported by stiff structures, one needs to define the system-level damping based upon the damping information of components. This is frequently done in practice using approximate methods expressed as composite modal damping with weighting functions. However, when the diff… more

Date: April 1, 1998

Creator: Xu, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Richland isotope production matrix

Isotope production calculations have been prepared in the past to indicate present and potential reactor capability; however, the cases evaluated generally considered production of only one or possibly two isotopes. With the wide variety and potential demand for numerous isotopes, the question arises as to what the production capability would be if several isotopes were being produced at the same time. To study this problem in more detail and determine which of several alternates may be used in… more

Date: May 12, 1966

Creator: Kushler, L. E. & Shimer, R. D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

One-dimensional transport code for one-group problems in plane geometry

Equations and results are given for various methods of solution of the one-dimensional transport equation for one energy group in plane geometry with inelastic scattering and an isotropic source. After considerable investigation, a matrix method of solution was found to be faster and more stable than iteration procedures. A description of the code is included which allows for up to 24 regions, 250 points, and 16 angles such that the product of the number of angles and the number of points is le… more

Date: September 1, 1970

Creator: Bareiss, E. H. & Chamot, C.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Two-dimensional finite element neutron diffusion analysis using hierarchic shape functions

Recent advances have been made in the use of p-type finite element method (FEM) for structural and fluid dynamics problems that hold promise for reactor physics problems. These advances include using hierarchic shape functions, element-by-element iterative solvers and more powerful mapping techniques. Use of the hierarchic shape functions allows greater flexibility and efficiency in implementing energy-dependent flux expansions and incorporating localized refinement of the solution space. The i… more

Date: April 1, 1997

Creator: Carpenter, D.C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Nerva Fuel Element Development Program Summary Report - July 1966 through June 1972 Extrusion Studies

This part of the completion report pertaining to the NERVA graphite fuel element program covers data collected during the extrusion studies. The physical properties of the fuel element reached the following values: coefficient of thermal expansion (CTE) - 7.0 x 10-6/o C (25 - l,OOOo C); modulus of elasticity - 1.5 x lo6 psi; flexural strength - - 8,000 psi; ultimate strain to failure - 5,500 pidin; good thermal stress resistance. Matrices were produced which could be vapor coated with crack-fre… more

Date: September 21, 1973

Creator: Napier, J. M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

A discrete ordinate response matrix method for massively parallel computers

A discrete ordinate response matrix method is formulated for the solution of neutron transport problems on massively parallel computers. The response matrix formulation eliminates iteration on the scattering source. The nodal matrices which result from the diamond-differenced equations are utilized in a factored form which minimizes memory requirements and significantly reduces the required number of algorithm utilizes massive parallelism by assigning each spatial node to a processor. The algor… more

Date: December 31, 1991

Creator: Hanebutte, U. R. & Lewis, E. E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Notice of Energy R&D Project

This is a research project involving the development of a computational methodology to predict the global neutron scalar flux and thermal power profiles throughout a nuclear reactor. This methodology is based on the utilization of high order polynomials within a Monte Carlo algorithm to accelerate Monte Carlo fission source iterations for loosely coupled reactor systems. Preliminary work has demonstrated the feasibility of using high order polynomials to estimate spatially and angularly varying… more

Date: October 2, 2004

Creator: Martin, William R. & Holloway, James P.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Direct solution of the mathematical adjoint equations for an interface current nodal formulation

A numerical method for directly computing the mathematical adjoint flux moments and partial currents for the hexagonal-Z geometry interface current nodal formulation in the DIF3D code is described. The new scheme is developed as an alternative to an existing scheme that employs a similarity transformation of the physical adjoint solution to compute the mathematical adjoint. Whereas the existing scheme is rigorous only when the flat transverse-leakage approximation is employed, this new scheme i… more

Date: March 1, 1993

Creator: Taiwo, T. A.; Yang, W. S. & Khalil, H. S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Comparison of uncertainty metrics for calculated dosimetry activities

Various metrics are formulated for the uncertainty of calculated neutron activities for dosimetry reactions. The correlations between the uncertainty metrics are examined. The uncertainty data are presented for the dosimetry reactions and can be used to guide the selection of sensors used in spectrum determinations.

Date: February 1, 1996

Creator: Griffin, P.J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

An overview of the current status of resonance theory in reactor physics applications

The neutron resonance phenomena constitute one of the most fundamental subjects in nuclear physics as well as in reactor physics. It is the area where the concepts of nuclear interaction and the treatment of the neutronic balance in reactor lattices become intertwined. The later requires the detailed knowledge of resonance structures of many nuclide of practical interest to the development of nuclear energy. The key issue of the resonance treatment in reactor applications is directly associated… more

Date: December 31, 1993

Creator: Hwang, R. N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A discrete ordinate response matrix method for massively parallel computers

Date: January 1, 1991

Creator: Hanebutte, U. R. & Lewis, E. E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

R-matrix analysis of the /sup 239/Pu neutron cross sections

/sup 239/Pu neutron cross-section data in the resolved resonance region were analyzed with the R-Matrix Bayesian Program SAMMY. Below 30 eV the cross sections computed with the multilevel parameters are consistent with recent fission and transmission measurements as well as with older capture and alpha measurements. Above 30 eV no suitable transmission data were available and only fission cross-section measurements were analyzed. However, since the analysis conserves the complete covariance mat… more

Date: January 1, 1985

Creator: Desaussure, G.; Perez, R.B. & Macklin, R.L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Direct solution of the mathematical adjoint equations for an interface current nodal formulation

Date: January 1, 1993

Creator: Taiwo, T. A.; Yang, W. S. & Khalil, H. S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Parameter and fluence-rate covariances in lepricon

The LEPRICON code system is now available from the Radiation Shielding Information Center at ORNL as PSR-277. The system consists of modules that involve both the calculation of neutron fluence rates through PWR pressure vessels and the adjustment of these fluence rates with reduced uncertainties based on surveillance dosimetry. This paper describes in detail the manner in which important parameter uncertainties are partitioned and quantified as part of the input to the adjustment procedure, an… more

Date: January 1, 1990

Creator: Maerker, R.E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Recent advances in utilization of the R-matrix parameters for reactor applications

A simplified version of the rigorous pole representation of cross sections has been developed to facilitate utilization of the newly released ENDF/B VI resonance data based on the Reich-Moore parameters for reactor applications. The procedure is equivalent to the extraction of the Humblet-Rosenfeld-type parameters and the associated background' term explicitly from the rigorous pole and residue parameters which, in turn, are converted from a given set of the Reich-Moore parameters. The computat… more

Date: January 1, 1991

Creator: Hwang, R.N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Benchmarking report for WIGGLE: A one-dimensional transient diffusion theory code

WIGGLE is a static/transient one-dimensional diffusion theory calculation written to estimate the axial power profile while safety rods are falling during a scram. The code is used in the LOCA Limits Analysis Package (LLAP), a part of the SRS system for calculating thermal-hydraulic limits. Since WIGGLE was designed to be implemented through LLAP and not as a stand-alone code, it consists entirely of subroutines; the problem data must be passed to it from a driver routine. This project concerne… more

Date: November 1, 1990

Creator: Pevey, R.E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Interface-flux nodal transport method

The development of the interface-flux nodal (IFN) method is presented to determine the flux distribution in reactor cells, cores and shielding. The method offers geometric flexibility, high order of spatial expansions of the node-interior sources and the node surface quantities. The surface-integral formulation is reduced to response-matrix-like global equations through coupling coefficients which are generalized expressions for escape and transmission probabilities. The spatial distribution of… more

Date: January 1, 1990

Creator: Kohut, P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Topics in data adjustment theory and applications

The methodologies of the uncertainty analysis and data adjustment have been well-developed and widely used abroad since the early 70's. With limited amount of covariance data on the differential cross section and the integral experiments available at the time, their accomplishments are, indeed, astounding. The fundamental adjustment equations, however, remain qualitatively unchanged. For the past few year, extensive efforts on these subjects have also begun at ANL in order to utilize the massiv… more

Date: January 1, 1988

Creator: Hwang, R.N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Reinforced Flexural Elements for TEMP-STRESS Program

The implementation of reinforced flexural elements into the thermal-mechanical finite element program TEMP-STRESS is described. With explicit temporal integration and dynamic relaxation capabilities in the program, the flexural elements provide an efficient method for the treatment of reinforced structures subjected to transient and static loads. The capability of the computer program is illustrated by the solution of several examples: the simulation of a reinforced concrete beam; simulations o… more

Date: June 1, 1987

Creator: Marchertas, A. H.; Kennedy, J. M. & Pfeiffer, P. A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Average values of sup 235 U resonance parameters up to 500 eV

An R-matrix analysis of {sup 235}U neutron cross sections was recently completed. The analysis was performed with the multilevel-multichannel Reich-Moore computer code SAMMY and extended the resolved resonance region up to 500 eV. Several high resolution measurements namely, transmission, fission and capture data as well as spin separated fission data were analyzed in a consistent manner and a very accurate parametrization up to 500 eV of these data were obtained. The aim of this paper is to pr… more

Date: January 1, 1991

Creator: Leal, L.C.

Item Type: Article

Partner: UNT Libraries Government Documents Department