Verification and Validation of Nuclear Data Processing by NJOY Using ACEtk and MCNP [Slides]
Abstract not provided.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
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New paradigm for nuclear data evaluation
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Nuclear Data↗
Recent Progress on Fission Nuclear Data
This report describes LANL's recent progress on nuclear fission.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Nuclear Data Sheets for A = 27
Evaluated spectroscopic data and level schemes from radioactive decay and nuclear reaction studies are presented for {sup 27}F, {sup 27}Ne, {sup 27}Na, {sup 27}Mg, {sup 27}Al, {sup 27}Si, {sup 27}P, and {sup 27}S. This evaluation for A=27 supersedes the earlier evaluation by P.M. Endt (1998En04 and 1990En08).
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Advances in Nuclear Data Evaluation Theory for NCSP [Slides]
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 evaluations of RRR including direct reactions, direct capture, and the Reich-Moore approx., doorway state reactions with applications to RPI data on lead isotopes. Extended R-Matrix formalism will be implemented into SAMMY post modernization.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Action Sheet 66: Neutron Induced Nuclear Data Cross Section Measurements at JRC-Geel [Slides]
Experiments for 142 Ce have been performed in 2019. The data are reduced to cross section and transmission, respectively. Report for 142 Ce experiments is in preparation. Data analysis is underway, and the evaluation should be finalized by the end of 2020. 90 Zr sample is produced, but experiments planned for 2020 are delayed due to COVID-19.
142Ce↗
Nuclear Data Sheets for A = 68
The experimental results from the various reaction and radioactive decay studies leading to nuclides in the A = 68 mass chain have been reviewed. Nuclides ranging from Cr (Z = 24) to Br (Z = 35) are included. For these nuclei, level and decay schemes, as well as tables of nuclear properties, are given. This work supersedes the previous evaluation of the data on these nuclides (2002Bu29).
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Machine learning selection of differential and integral experiments to optimally reduce nuclear data uncertainties [Slides]
Abstract not provided.
Nuclear Criticality Safety Program (NCSP)↗
Nuclear Data Sheets for A = 28
Evaluated spectroscopic data and level schemes from radioactive decay and nuclear reaction studies are presented for {sup 28}F, {sup 28}Ne, {sup 28}Na, {sup 28}Mg, {sup 28}Al, {sup 28}Si, {sup 28}P, and {sup 28}S. This evaluation for A=28 supersedes the earlier evaluations by P.M. Endt (1998En04 and 1990En08). However, additional/detailed data for these nuclides can be found in earlier evaluations 1978En02 and 1973EnVA also by P.M. Endt.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Validation of ENDF/B-VIII.1 Nuclear Data Files [Slides]
ENDF-6 formatted files were processed into A Compact ENDF (ACE) files using NJOY2016. Several validation tests were performed: (1) LANL Legacy Benchmark Suite (2) “Modern” Benchmark Suite (3) HEU Benchmark Suite (4) LEU Benchmark Suite (5) Mixed (U+Pu) Benchmark Suite (6) Pu Benchmark Suite (7) 233 U Benchmark Suite.
97 MATHEMATICS AND COMPUTING↗
Overview of Nuclear Data Measurement and Analysis at RP [Slides]
This presentation details neutron capture in 54 Fe along with neutron capture yield and γ-ray cascade spectra measurements. The presentation then follows with thermal neutron die-away measurements and concludes with URR improvement to SAMMY.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
International Nuclear Data Evaluation Network (INDEN) on the Evaluation of Light Elements
The INDEN for Light Elements network (INDEN-LE) held a consultants’ meeting from 20 to 23 June 2022, to review the status of the evaluations undertaken by the network as well as developments in R-matrix theory and new measurements. The summaries of the presentations and discussions can be found in this report.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Bayesian Monte-Carlo Evaluation Framework for Imperfect Nuclear Data [Slides]
BMC evaluation is a tool used to address imperfect data and models, non-linear models, and non-normal PDFs. ENDF-6 format does not allow non-normal parameter PDFs. Storing posterior sets allows for variance, covariance, skewness, etc. To better predict criticality, we should document non-normal parameter PDFs (i.e. asymmetric uncertainty) and consider non-linear sensitivity of $k_{\text{eff}}$ to resonance parameters.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Continuous energy cross section adjustment: a new method to generalize nuclear data assimilation for a wider range of applications.
This work presents a new method to perform continuous-energy cross section adjustment. The proposed method is based on recently developed Monte Carlo perturbation capabilities with continuous-energy sensitivity functions implemented in an extended Serpent version. The generation of continuous energy basis functions aseigendecomposition of the covariance matrices and the Generalized Least Squares method applied to these functions are described. The new approach is verified against standard, multi-group adjustment methodologies in a case study involving four different response functions in Jezebel. The results obtained by the two approaches for the selected case study are presented and compared in term of adjusted cross sections, adjusted covariance matrices, and uncertainty reduction.
22 GENERAL STUDIES OF NUCLEAR REACTORS↗
Using NJOY to Create MCNP ACE Files and Visualize Nuclear Data
We provide lecture materials for a two-day introductory NJOY2012 class.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Effects of Hydrogen Bonding on Nuclear Data Development of Liquid Anhydrous HF
Anhydrous Hydrogen Fluoride (HF) at high temperatures and pressures is used to process and manufacture nuclear fuel. As HF is often used directly with uranium, correct neutron thermal scattering cross sections are crucial to criticality safety applications. Classical molecular dynamics (CMD) simulation of the flexible HF system was used to create the thermal scattering law (TSL) and cross sections. The initial 2-site model is used in LAMMPS, and it can not capture the H-bond. To correctly represent the H-bond effects, a second, 3-site model was constructed in GROMACS. The 3-site model handled H-bonds by connecting a massless charge to the molecule. Key model parameters were compared to experimental data to verify the approach and models. To get the normalized VACF, the model was compared using hydrogen and fluorine bond length, density, potential energy, and diffusion coefficient. The phonon DOSs for both models were derived from the normalized VACF. DOSs were used to estimate the TSL ( S ( α, β )) and neutron thermal scattering cross sections for hydrogen in HF. The TSLs were evaluated using the FLASSH code with the Schofield diffusion model. It was observed that the representation of the hydrogen bonding changes the TSL's diffusional contributions. This is represented in the low energy scattering cross section, where intermolecular binding effects shift the cross section.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗