Andrew Holcomb
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View article: Towards an Energy Deposition Tally in SCALE/MAVRIC
Towards an Energy Deposition Tally in SCALE/MAVRIC Open
View article: SG50 Data-format Requirement Document for an Automatically Readable, Comprehensive and Curated Experimental Reaction Database MEDUSA
SG50 Data-format Requirement Document for an Automatically Readable, Comprehensive and Curated Experimental Reaction Database MEDUSA Open
This report constitutes the requirement document that guides the development of the experimental reaction database, MEDUSAL (Machine-readable Experimental Data User App & Library), created by OECD/NEA/WPEC SubGroup 50. Experimental reactio…
View article: Dancoff-Based Wigner-Seitz Approximation for the Embedded Self-Shielding Method in SCALE/Polaris
Dancoff-Based Wigner-Seitz Approximation for the Embedded Self-Shielding Method in SCALE/Polaris Open
View article: Improvement of SCALE-XSPROC Multigroup Cross Section Processing Based on the CENTRM Pointwise Slowing Down Calculation
Improvement of SCALE-XSPROC Multigroup Cross Section Processing Based on the CENTRM Pointwise Slowing Down Calculation Open
The SCALE-XSProc multigroup (MG) cross section processing procedure based on the CENTRM pointwise slowing down calculation is the primary procedure to process problem-dependent self-shielded MG cross sections and scattering matrices for ne…
View article: Free Gas Elastic Scattering Algorithm for GPU-Based Particle Tracking
Free Gas Elastic Scattering Algorithm for GPU-Based Particle Tracking Open
View article: NEA GitLab: A centralised platform for development and deployment of nuclear codes and data
NEA GitLab: A centralised platform for development and deployment of nuclear codes and data Open
The NEA Data Bank is an international reference centre for computer codes, nuclear and thermochemical data which has traditionally used simple file servers, and even DVDs, to deliver valuable content to end users across the globe. With the…
View article: SCALE/DB-Public
SCALE/DB-Public Open
This is a collection of public data produced by AMPX or curated from quality sources that the SCALE code system relies on for user problem input.
View article: Revisit of the Dancoff-Based Wigner-Seitz Approximation for Pointwise and Multigroup Resonance Self-Shielding Calculations in SCALE
Revisit of the Dancoff-Based Wigner-Seitz Approximation for Pointwise and Multigroup Resonance Self-Shielding Calculations in SCALE Open
View article: Bayesian Monte Carlo Evaluation Framework for Imperfect Nuclear Data
Bayesian Monte Carlo Evaluation Framework for Imperfect Nuclear Data Open
Bayesian evaluation of resolved resonance region (RRR) nuclear data has historically been carried out using the generalized least squares (GLS) formalism, as implemented in, e.g., SAMMY. We have recently developed a prototype of Bayesian M…
View article: Integrated, Automated, and Reproducible Nuclear Data Processing at the NEA
Integrated, Automated, and Reproducible Nuclear Data Processing at the NEA Open
Ensuring data preservation is a top priority for the Organization for Economic Co-operation and Development (OECD), Nuclear Energy Agency (NEA) Data Bank. Within this context, “preserving data” encompasses activities such as verifying, pro…
View article: ENDF/B-VIII.0 Testing With AMPX and SCALE
ENDF/B-VIII.0 Testing With AMPX and SCALE Open
As the new ENDF/B-VIII.0 data has continued development from its initial beta release into the final release version, it has subsequently undergone processing and testing at Oak Ridge National Laboratory with AMPX and SCALE. Each of the be…
View article: VALIDATION OF KENO V.A AND KENO-VI IN SCALE 6.3 BETA 3 USING ENDF/B-VII.1 AND ENDF/B-VIII LIBRARIES
VALIDATION OF KENO V.A AND KENO-VI IN SCALE 6.3 BETA 3 USING ENDF/B-VII.1 AND ENDF/B-VIII LIBRARIES Open
In early 2019, internal beta releases of SCALE 6.3 were identified for internal users, as well as a limited number of external users, to apply when testing key features. Recently developed AMPX-formatted libraries based on ENDF/B-VIII have…
View article: A Testing Trifecta: Data, Codes, and Evaluations
A Testing Trifecta: Data, Codes, and Evaluations Open
View article: Verification of the ENDF/B-VII.1 and VIII.0 AMPX 1597-Group Libraries for Advanced Reactor Analysis
Verification of the ENDF/B-VII.1 and VIII.0 AMPX 1597-Group Libraries for Advanced Reactor Analysis Open
The SCALE/AMPX multigroup (MG) cross section processing procedure has been updated to minimize reactivity differences for various advanced thermal and fast reactor designs, as observed for the current MG libraries, resulting in excellent a…
View article: ENDF/B-VIII.0 Augmented Covariance Data: The first iteration
ENDF/B-VIII.0 Augmented Covariance Data: The first iteration Open
Nuclear data are necessary for reliable modeling and simulation of the next generation of nuclear reactors. However, the variation in the ratio of the computed to experimental values (C/E) for certain types of nuclear systems is much less …
View article: Summary: Verification of the ENDF/B-VII.1 and VIII.0 AMPX 1597-group Libraries for Advanced Reactor Analysis
Summary: Verification of the ENDF/B-VII.1 and VIII.0 AMPX 1597-group Libraries for Advanced Reactor Analysis Open
The SCALE/AMPX multigroup (MG) cross section processing procedure has been updated to minimize reactivity differences for various advanced thermal and fast reactor designs, as observed for the current MG libraries, resulting in excellent a…
View article: Bayesian Monte Carlo Evaluation Framework for Imperfect Data and Models [Abstract]
Bayesian Monte Carlo Evaluation Framework for Imperfect Data and Models [Abstract] Open
Nuclear data evaluation methods conventionally make the following assumptions: prior and posterior probability distribution functions (PDFs) of all model parameters and data are normal (Gaussian); the linear approximation is sufficiently a…
View article: A Subcritical Assembly for Training and Education Use at the Oak Ridge National Laboratory [Abstract]
A Subcritical Assembly for Training and Education Use at the Oak Ridge National Laboratory [Abstract] Open
A near-final design has been completed for a new subcritical assembly at Oak Ridge National Laboratory (ORNL). This subcritical assembly will support the Nuclear Criticality Safety Program (NCSP) training and education program to augment c…
View article: Phenomenological <em>R</em>-Matrix parameterization of direct, doorway, and compound nuclear reactions [Abstract]
Phenomenological <em>R</em>-Matrix parameterization of direct, doorway, and compound nuclear reactions [Abstract] Open
Although formal expressions for scattering matrix accounting for direct, doorway, and compound nuclear (CN) resonant reactions have been derived several decades ago in both the transition (T-)matrix formalism and the reactance (
View article: Bayesian Evaluation Framework for <em>Imperfect</em> Differential and Integral Data or Models [Slides]
Bayesian Evaluation Framework for <em>Imperfect</em> Differential and Integral Data or Models [Slides] Open
This presentation is on Bayesian evaluation framework for imperfect differential and integral data or models. This presentation includes a particular focus on common assumptions used in Bayesian ND evaluations. Additionally, this presentat…
View article: Modernization efforts for the <i>R</i>-Matrix code SAMMY
Modernization efforts for the <i>R</i>-Matrix code SAMMY Open
The R-Matrix code SAMMY [1] is a widely used nuclear data evaluation code focused on the resolved range, which includes corrections for experimental effects. The code is still mostly written in FORTRAN 77 and uses a memory management syste…
View article: Bayesian Monte Carlo Evaluation of <i>Imperfect</i> (<i>n</i>, <sup>233</sup>U) Data and Model
Bayesian Monte Carlo Evaluation of <i>Imperfect</i> (<i>n</i>, <sup>233</sup>U) Data and Model Open
Conventional nuclear data evaluation methods using generalized linear least squares make the following assumptions: prior and posterior probability distribution functions (PDFs) of all model parameters and data are normal (Gaussian); the l…
View article: Modernization efforts for the <em>R</em>-Matrix code SAMMY [Abstract]
Modernization efforts for the <em>R</em>-Matrix code SAMMY [Abstract] Open
The R-Matrix code SAMMY is a widely used nuclear data evaluation code focused on the resolved range, which includes corrections for experimental effects. The code is still mostly written in Fortran 77, and uses a memory management system s…
View article: Phenomenological R-Matrix parameterization of direct, doorway, and compound nuclear reactions [Slides]
Phenomenological R-Matrix parameterization of direct, doorway, and compound nuclear reactions [Slides] Open
The presented R-matrix formalism could improve evaluations of resolved resonance nuclear cross section data by parameterizing direct reaction processes via an orthonormal channel mixing matrix and doorway state processes. Together, they ca…
View article: Modernization efforts for the R-Matrix code SAMMY [Slides]
Modernization efforts for the R-Matrix code SAMMY [Slides] Open
This presentation details modernization efforts for the R-Matrix code SAMMY. It provides an overview of SAMMY, modernization and maintenance goals, modernization accomplishments, covariance data, SAMMY API development, as well as future pl…
View article: Isotope Effects in Thermal Neutron Scattering [Slides]
Isotope Effects in Thermal Neutron Scattering [Slides] Open
AMPX links Thermal Scattering Law (TSL) libraries to isotopes in the resolved resonance region. No guidance is given in the TSL files or the ENDF format if this is acceptable or advised, which can lead to several issues. This presentation …
View article: Continuous-Energy ENDF/B-VIII.0 Cross Section and SCALE 6.2.4 Performance for Nuclear Criticality Safety Applications: <sup>1</sup>H, C, <sup>58,60</sup>Ni, <sup>182,183,184,186</sup>W, <sup>235,238</sup>U, <sup>239</sup>Pu
Continuous-Energy ENDF/B-VIII.0 Cross Section and SCALE 6.2.4 Performance for Nuclear Criticality Safety Applications: <sup>1</sup>H, C, <sup>58,60</sup>Ni, <sup>182,183,184,186</sup>W, <sup>235,238</sup>U, <sup>239</sup>Pu Open
As part of the nuclear data evaluation and validation cycle, the ENDF/B-VIII.0 cross-section library released in 2018 requires testing to determine areas of improvement and deterioration. Previous work by the authors investigated the perfo…
View article: Bayesian Monte-Carlo Framework: New Methods for Resonance Parameter Evaluation [Slides]
Bayesian Monte-Carlo Framework: New Methods for Resonance Parameter Evaluation [Slides] Open
BMC evaluation is a tool to address imperfect data & models, non-linear models, and non-normal PDFs. ENDF-6 format does not allow non-normal parameter PDFs. Storing posterior sets allow for variance, covariance, skewness, etc. To better pr…
View article: SAMMY Modernization Efforts [Slides]
SAMMY Modernization Efforts [Slides] Open
This presentation details several SAMMY modernization and maintenance goals, as well as the efforts made towards these goals and future plans for SAMMY.
View article: Advances in Nuclear Data Evaluation Theory for NCSP [Slides]
Advances in Nuclear Data Evaluation Theory for NCSP [Slides] Open
The generalized form of the Bayes’ Theorem improves UQ for NCSP of differential and/or integral data evaluations and of applications. It is being implemented in an API for use by SCALE, SAMMY, etc. Extended R-matrix formalism improves eval…