SCONE Guide

❮ Cross Section DataVariance Reduction ❯

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.

Official SCONE documentationSCONE on GitHubIssues & discussions

Configuring Nuclear Data in SCONE

Getting Started

Proper nuclear data configuration is crucial for accurate SCONE simulations. All materials and cross-section handles are defined in the nuclearData block. The handles section points to ACE-format cross-section libraries; the materials section defines compositions using ZAID.NN and number density pairs.

plaintext
nuclearData {
  handles {
    ce { type aceNeutronDatabase; aceLibrary /path/to/JEF311.aceXS; }
  }
  materials {
    Water {
      temp 600;
      composition {
        5010.06 7.9714E-06;
        5011.06 3.2247E-05;
        1002.06 7.7035E-06;
        8016.06 2.4673E-02;
      }
    }
    UO2-31 {
      temp 600;
      composition {
        8016.06  4.5853E-02;
        92235.06 7.2175E-04;
        92238.06 2.2253E-02;
      }
    }
    Zircaloy {
      temp 600;
      composition {
        40090.06 2.1828E-02;
        40091.06 4.7601E-03;
        40092.06 7.2759E-03;
        40094.06 7.3734E-03;
        40096.06 1.1879E-03;
      }
    }
  }
}

Each material has a temp (temperature in Kelvin) and a composition block. The composition lists ZAID.NN identifiers (e.g., 92235.06 for U-235 at 600K) with number densities in atoms per barn-cm. Material names (Water, UO2-31, Zircaloy) are referenced in the geometry cells.

Fuel Compositions at Different Enrichments

Reactor models often use multiple UO2 enrichments. Define each as a separate material with the appropriate U-235 fraction. The numbers shown are typical for PWR fuel at 600K (number densities from BEAVRS benchmark).

plaintext
materials {
  UO2-16 {
    temp 600;
    composition {
      8016.06  4.5897E-02;
      92235.06 3.7503E-04;
      92238.06 2.2625E-02;
    }
  }
  UO2-24 {
    temp 600;
    composition {
      8016.06  4.5830E-02;
      92235.06 5.5814E-04;
      92238.06 2.2407E-02;
    }
  }
  UO2-31 {
    temp 600;
    composition {
      8016.06  4.5853E-02;
      92235.06 7.2175E-04;
      92238.06 2.2253E-02;
    }
  }
}

Structural and Moderator Materials

Borated water (moderator), Zircaloy (cladding), and structural alloys (stainless steel, Inconel) follow the same pattern. Water with boron uses B-10 and B-11 in the composition. Structural materials include Cr, Fe, Ni, and other alloying elements.

plaintext
materials {
  StainlessSteel304 {
    temp 600;
    composition {
      24050.06 7.6778E-04;
      24052.06 1.4806E-02;
      26054.06 3.4620E-03;
      26056.06 5.4345E-02;
      28058.06 5.6089E-03;
      28060.06 2.1605E-03;
      14028.06 9.5281E-04;
    }
  }
  Inconel {
    temp 600;
    composition {
      24050.06 7.8239E-04;
      24052.06 1.5088E-02;
      26054.06 1.4797E-03;
      26056.06 2.3229E-02;
      28058.06 2.9320E-02;
      28060.06 1.1294E-02;
      14028.06 5.6757E-04;
    }
  }
}

Configuration Tips

Ensure the aceLibrary path points to a valid ACE file. All ZAID.NN values in material compositions must exist in that library. Use consistent temperature indices (e.g., .06 for 600K) across materials that share the same operating temperature.

Test your configuration with simple benchmark problems before running production calculations. Document your library path and material definitions for reproducibility.

Related Topics

❮ Cross Section DataVariance Reduction ❯