SCONE Guide

❮ GeometryConfiguration ❯

SCONE Verification Notice

SCONE is a research-oriented code with a smaller user base than MCNP, OpenMC, or SERPENT. Our examples are intended as educational guidance. For authoritative syntax, physics options, and nuclear data requirements, consult the official documentation.

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Nuclear Materials in SCONE

Defining compositions and cross-section references for neutron transport

Every material name in geometry must appear under nuclearData.materials with the same spelling. Match temp (K) to each ZAID suffix per your ACE build. Compositions are atomic number densities in atoms/(cm·barn), not mass fractions. The first listing is from tutorial_nuclear_data_basic_testlib (run_all.ps1); the second from tutorial_examples_hub_testlib — both use testLib-style .03 indices and $SCONE_ACE for local runs.

Material Properties

Materials in SCONE define how neutrons interact with different regions of your geometry. Each material requires a temperature specification that affects nuclear cross-sections, and a composition listing nuclides at the density basis used by your library workflow. The examples below use ACE-based `nuclearData` with block-style syntax.

tutorial_nuclear_data_basic_testlib (lines 51–67)
nuclearData {
  handles { ce { type aceNeutronDatabase; aceLibrary $SCONE_ACE; } }
  materials {
    Water {
      temp 600;
      composition { 1001.03 6.67e-02; 8016.03 3.33e-02; }
    }
    UO2-31 {
      temp 600;
      composition { 92235.03 4.50e-02; }
    }
    Zircaloy {
      temp 600;
      composition { 1001.03 6.67e-02; 8016.03 3.33e-02; }
    }
  }
}
caalh/ReactorMCBrowse filesscone-examples/verify/tutorial_nuclear_data_basic_testlib

Verify harness (testLib + run_all.ps1)

The handles section points to your ACE library. In the excerpt, aceLibrary $SCONE_ACE is the pattern used in verify decks (set the environment variable to IntegrationTestFiles/testLib or your own .aceXS). SCONE expects a library file format (see IntegrationTestFiles/testLib in the SCONE repo); you can generate one from raw ACE files using scripts/make_ace_lib.sh.

Each material has temp (temperature in Kelvin) and a composition block. The composition lists ZAID with a temperature index (e.g. 1001.06); the physical temperature that index maps to comes from how your ACE library was processed—match temp and suffix to that library. Densities are in atoms per barn-centimeter. Material names are referenced in geometry cells.

Advanced Features

For core models, the practical complexity is isotope completeness and consistency across structural and fuel materials, not optional keyword tuning.

tutorial_examples_hub_testlib (lines 47–55)
nuclearData {
  handles { ce { type aceNeutronDatabase; aceLibrary $SCONE_ACE; } }
  materials {
    fuel  { temp 600; composition { 92235.03 4.50e-02; } }
    gap   { temp 600; composition { 1001.03 6.67e-02; 8016.03 3.33e-02; } }
    clad  { temp 600; composition { 1001.03 6.67e-02; 8016.03 3.33e-02; } }
    water { temp 600; composition { 1001.03 6.67e-02; 8016.03 3.33e-02; } }
  }
}
caalh/ReactorMCBrowse filesscone-examples/verify/tutorial_examples_hub_testlib

Verify harness (testLib + run_all.ps1)

This pattern shows four named materials in one block (pin-cell style). For production libraries, replace .03 with your evaluation's suffix (often .06), expand nuclide lists, and set aceLibrary to your processed file instead of $SCONE_ACE.

Material Tips

Use the ZAID plus temperature-index format (e.g. 92235.06). The digits after the dot are library-specific temperature/table indices—common conventions (e.g. .03 vs .06) are not guaranteed for every ACE file. Set temp and ZAID suffixes consistently with the tables listed in your aceLibrary file. Densities are in atoms per barn-centimeter.

Related Topics

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