NJOY vs FRENDY Cross Section Comparison

This repository provides a framework for comparing evaluated nuclear data processed by two major nuclear data processing systems: NJOY and FRENDY.

📘 Overview

The goal of this project is to:

• Process ENDF-formatted nuclear data files using both NJOY and FRENDY.
• Extract and visualize ACE-format cross section data.
• Perform a systematic comparison between the two outputs.
• Identify discrepancies and evaluate consistency across different energy groups and reactions.

🔧 Installation (Linux / Ubuntu)

📋 Prerequisites

NJOY2016

Ensure the following packages are installed:

sudo apt update
sudo apt install git cmake gfortran build-essential octave

####To download and compile NJOY2016:

git clone https://github.com/njoy/NJOY2016.git
cd NJOY2016
mkdir build
cd build
cmake -DCMAKE_BUILD_TYPE=Release ../
make -j$(nproc)

FRENDY

Ensure the following packages are installed:

sudo apt-get update
sudo apt-get upgrade
sudo apt-get install tcsh build-essential gcc libboost-all-dev liblapack-dev libblas-dev libeigen3-dev
wget https://rpg.jaea.go.jp/download/frendy/frendy_20241030.tar.gz
tar -xvzf frendy_YYYYMMDD.tar.gz
cd frendy_YYYYMMDD/frendy
csh ./compile_all.csh
cd sample/run
csh ./run_frendy.csh

Running

Frendy running :

git clone https://github.com/emilmammadzada99/njoy-frendy-comparison.git
cd njoy-frendy-comparison/fr/
:~/fr$ cp n-092_U_238.endf tape20
:~/fr$ ~/frendy_20241030/frendy/main/frendy.exe n-092_U_238.dat

NJOY running:

cd njoy-frendy-comparison/nj/
:~/nj$ cp n-092_U_238.endf tape20
:~/nj$ njoy < n-092_U_238.njoy

Comparison Plotting :

cd njoy-frendy-comparison/
:~/njoy-frendy-comparison$ chmod +x compare.csh   
:~/njoy-frendy-comparison$ ./compare.csh # created out directory in njoy-frendy-comparison for comparison
:~/njoy-frendy-comparison$ chmod +x  plot_all.csh
:~/njoy-frendy-comparison$ ./plot_all.csh # created ace_plot  ace_plot_only directory in njoy-frendy-comparison for comparison

Plotting Only Frendy Data:

cd njoy-frendy-comparison/fr_single/
:~/njoy-frendy-comparison/fr_single$ cp -r ~/njoy-frendy-comparison/fr  ~/njoy-frendy-comparison/fr_single
:~/njoy-frendy-comparison/fr_single$ chmod +x plot_single.csh
:~/njoy-frendy-comparison/fr_single$ ./plot_single.csh #create only frendy data out directory
:~/njoy-frendy-comparison/fr_single$ chmod +x plot_frendy.csh
:~/njoy-frendy-comparison/fr_single$ ./plot_frendy.csh #create plot directory

Comparison Plotting with Octave:

cd njoy-frendy-comparison/gnuplot/
:~/njoy-frendy-comparison/gnuplot$ cp -r ~/njoy-frendy-comparison/out ~/njoy-frendy-comparison/gnuplot
:~/njoy-frendy-comparison/gnuplot$ mv out comp_out
:~/njoy-frendy-comparison/gnuplot$ cp -r ~/njoy-frendy-comparison/fr_single/out ~/njoy-frendy-comparison/gnuplot
:~/njoy-frendy-comparison/gnuplot$ mv out single_out && ls
comp_out single_out 
:~/njoy-frendy-comparison/gnuplot$ mkdir comp_plot single_plot
:~/njoy-frendy-comparison/gnuplot$ cd single_plot
:~/njoy-frendy-comparison/gnuplot/single_plot$ octave plot_single.m  #plot directory created
:~/njoy-frendy-comparison/gnuplot/comp_plot$ octave plot_xs.m #created ace_plot  ace_plot_only directory in njoy-frendy-comparison for comparison

Images

📦 Contents of tape30

The tape30 file contains:

• Processed neutron cross sections
• Angular and energy distributions
• Reaction data for neutron interactions
• Thermal scattering law (TSL) data (if applicable)

🔑 Keywords

njoy frendy cross-section ENDF/B nuclear data ACE file MCNP SERPENT OpenMC gnuplot octave neutron transport data processing

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🛠️ Usage

tape30 is compatible with various Monte Carlo transport codes:

• MCNP — used with xsdir file
• SERPENT — can directly read ACE files
• OpenMC — requires conversion to HDF5 (.h5) format using OpenMC’s tools

📝 Notes

• The name tape30 is conventional; you can rename it to fit your transport code's requirements.
• TSL data may also involve tape33 and tape35, but the consolidated ACE output is placed in tape30.

📚 References

• NJOY2016 GitHub Repository
• FRENDY
• ENDF/B-VIII.0 Nuclear Data Library
• FRENDY-Exercises
• FRENDY-Installation
• NJOY2016 Manual PDF

Zenodo DOI

Mammadzada, E. (2025). emilmammadzada99/njoy-frendy-comparison:A comparative study on nuclear data processed by NJOY and FRENDY initial Public Release (v1.0). Zenodo. https://doi.org/10.5281/zenodo.15872841