Getting started: first example

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Within the installation directory, the gettingstarted/FNS_Inconel/ folder contains a set of inputs:

   collapse.i    condense.i    files    fluxes
   inventory.i   print_lib.i

FISPACT-II can be run with 0, 1 or 2 arguments:

fispact [argument 1] [argument 2]
  • 0 arguments: FISPACT-II will search for (in order) files, Files and FILES, taking the first found and reading all I/O files from this file.
  • 1 argument: FISPACT-II will still search for files, Files and FILES, but will take [argument 1] as the fileroot. It will then use the following I/O filenames:
    • input: fileroot.i
    • output: fileroot.out
    • runlog: fileroot.log
    • graph: fileroot.gra
    • tabn: fileroot.tabn (where n=1-4)
    • gnuplot: fileroot.plt
    • sensitivity: fileroot.sens
  • 2 arguments: FISPACT-II will take [argument 1] as the fileroot and search for [argument 2] for all of the I/O file data instead of files, Files or FILES.

Within the files file all of the mapped directories and outputs are specified. This should include all of the nuclear data files which will be used in a simulation, including an index of nuclides, particle-induced cross sections, fission yields, decays, etc. For this example, the file specifies

# Index of nuclides to be included
ind_nuc ../../ENDFdata/TENDL2014data/tendl14_decay12_index

# Library cross section data
xs_endf ../../ENDFdata/TENDL2014data/tal2014-n/gxs-709

# Library probability tables for self-shielding
prob_tab ../../ENDFdata/TENDL2014data/tal2014-n/tp-709-294

# Incident fluxes
fluxes fluxes

# Library decay data
dk_endf ../../ENDFdata/decay/decay_2012

# Library fission data
fy_endf ../../ENDFdata/TENDL2014data/tal2014-n/gef42_nfy
sf_endf ../../ENDFdata/TENDL2014data/tal2014-n/gef42_sfy

# Library regulatory data
hazards ../../ENDFdata/decay/hazards_2012
clear ../../ENDFdata/decay/clear_2012
a2data ../../ENDFdata/decay/a2_2012
absorp ../../ENDFdata/decay/abs_2012

# Collapsed cross section data (in and out)
collapxi COLLAPX
collapxo COLLAPX

# Condensed decay and fission yield data (in and out)
arrayx ARRAYX

The hashed comments provide intuitive descriptions, and are followed by two-column entries which give a FISPACT-II file keyword followed by either a directory or file location. For example, the first entry ind_nuc provides the file location for the list of nuclides to be included in the simulation index, the xs_endf points to the directory containing all of the ENDF-formatted cross section data, etc. While most of these file unit names are intuitive, a complete dictionary is provided in the manual.

The fluxes file contains the incident particle spectrum which is typically supplied by the code user. These are broken down into some group structure which must be identical to the group structure employed by the nuclear data files to be used. Spectra which have been set into another group structure can be easily converted into one of the FISPACT-II group structures using the example found in getting_started/flux_convert/. Note that these conversions must be done with care, as user-supplied spectra with very coarse group structures will often introduce errors when converted to use fine group data.

The remaining input files ending in .i can be run in sequence to perform the spectrum/cross-section collapse (convolution to determine reaction rates), decay and fission yield condensation and the irradiation simulation. The print_lib provides some additional cross section outputs.