SCONE Guide
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.
Configuring Nuclear Data in SCONE
ACE libraries, material compositions, and ZAID format
Getting Started
Cross Section Data goes deeper on ACE and ZAID notation; here we focus on reactor-style libraries (borated water, multiple UO₂ enrichments, alloys). Proper nuclear data configuration is crucial: all materials and handles live in the nuclearData block — handles for the ACE library, materials for ZAID.NN and number densities.
The file below is a minimal PWR-style pin eigen problem included in scone-examples/verify/run_all.ps1 with SCONE_ACE=IntegrationTestFiles/testLib. Material names Water, UO2-31, and Zircaloy match common reactor inputs; nuclide lists use test-library isotopes (.03) so the deck runs in the harness—swap in your aceLibrary path and the richer compositions from the excerpt after it for production libraries.
// ===================================================================
// NuclearData.tsx — full eigen deck (testLib) for run_all.ps1
// Material names match the PWR-style “Getting started” example on the site
// (Water, UO2-31, Zircaloy). Compositions use testLib nuclides (.03) only;
// production libraries add B, D, Zr isotopes and .06 indices as in the
// paste-only excerpts on the same page.
// ===================================================================
type eigenPhysicsPackage;
pop 10000;
active 50;
inactive 20;
XSdata ce;
dataType ce;
collisionOperator { neutronCE { type neutronCEstd; } }
transportOperator { type transportOperatorDT; }
inactiveTally {}
activeTally {
fissionRate {
type collisionClerk;
response (fission);
fission { type macroResponse; MT -6; }
}
}
// ===================================================================
// GEOMETRY
// ===================================================================
geometry {
type geometryStd;
boundary ( 0 0 0 0 0 0 );
graph { type shrunk; }
surfaces {
boxSq { id 5; type zSquareCylinder; origin (0.0 0.0 0.0); halfwidth (0.63 0.63 0.0); }
}
cells { }
universes {
root { id 1; type rootUniverse; border 5; fill u<31000>; }
pin31 { id 31000; type pinUniverse; radii (0.39218 0.40005 0.45720 0.0); fills (UO2-31 Zircaloy Water); }
}
}
// ===================================================================
// NUCLEAR DATA (testLib — see header)
// ===================================================================
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; }
}
}
}
Verify harness (testLib + run_all.ps1)
Production-style nuclearData excerpt (JEF path and .06 indices — requires matching ACE; not part of the testLib harness)
Not in run_all.ps1 — nuclearData block only; merge with your geometry and physics from a full deck.
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;
}
}
}
}Tutorial snippet — no separate file in examples repo
Each material has a temp (temperature in Kelvin) and a composition block. The composition lists ZAID plus a temperature/table index (e.g. 92235.06) with number densities in atoms per barn-cm; interpret the suffix using your ACE library's documentation. Material names 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 600 K. The block below is a paste-ready nuclearData excerpt (same handles + materials structure as above).
Not in run_all.ps1 — excerpt only.
nuclearData {
handles {
ce { type aceNeutronDatabase; aceLibrary /path/to/JEF311.aceXS; }
}
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;
}
}
}
}Tutorial snippet — no separate file in examples repo
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.
Not in run_all.ps1 — excerpt only.
nuclearData {
handles {
ce { type aceNeutronDatabase; aceLibrary /path/to/JEF311.aceXS; }
}
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;
}
}
}
}Tutorial snippet — no separate file in examples repo
Configuration Tips
Ensure the aceLibrary path points to a valid library file. Every ZAID in your compositions must appear in that library with a matching temperature index. Keep indices consistent across materials that should use the same tables.
Test your configuration with simple benchmark problems before running production calculations. Document your library path and material definitions for reproducibility.