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- openmcPWR
OpenMC — BEAVRS Cycle 1 Full-Core PWR (run-verified translation)
OpenMC (Python) build script translating the author-verified SCONE BEAVRS full core: 17×17 RectLattice assemblies on the real 193-assembly loading map (1.6/2.4/3.1 wt% UO2) with 24 guide tubes + central instrument tube, Pyrex burnable-poison rods, control rods withdrawn, and core barrel/RPV. Uses openmc.IndependentSource, Material.set_density with atom densities, temperature (600 K) on cells, and c_H_in_H2O S(a,b) on water only; run model.run(threads=N) then openmc.StatePoint(path). Material number densities are the verified deck's values; whatever OPENMC_CROSS_SECTIONS points at is used (cross-library k-eff bias expected). RUN-VERIFIED in OpenMC 0.15.3 with full ENDF/B-VIII.0 nuclide coverage: geometry passes OpenMC's overlap check (no overlaps, no lost particles) and the deck runs end-to-end to k-eff = 0.99737 ± 0.00030 (40 inactive + 100 active cycles, 100k particles/cycle) — physically sensible for the deck as written (BEAVRS Cycle-1 HZP, ~977 ppm soluble boron, all rods out → expected k ≈ 1.0). Caveat: the H-in-H2O thermal kernel ran at 294 K (only temperature available locally) while neutron data was at exactly 600 K. Still a spec-derived translation — NOT benchmark-validated against measured BEAVRS data. Now AXIALLY COMPLETE: full ~25-layer axial build per pin (active fuel z 36.748-402.508 cm segmented by 8 Inconel grid spacers; plenum/spring, SS top nozzle, support plates, guide-tube dashpot, Pyrex BA + plenum stacks, end plugs) ported from the verified SCONE deck. Now also RADIALLY COMPLETE: per-assembly Pyrex BA clusters (real 6/12/15/16/20-rod patterns), the stepped SS304 baffle/former, the four octant neutron-shield pads, downcomer water and RPV rings all ported from the verified SCONE core; no radial simplifications remain. Not an official MIT/CRPG product. Source: openmc-examples/beavrs_fullcore.py.
by @caalh·10 days ago - serpentPWR
Serpent — BEAVRS Cycle 1 Full-Core PWR (spec-derived translation)
Serpent 2 translation of the author-verified SCONE BEAVRS full core: pin/lat universes on the real 193-assembly loading map (1.6/2.4/3.1 wt% UO2) with 24 guide tubes + central instrument tube, Pyrex burnable-poison rods, control rods withdrawn, and core barrel/RPV. Energies in MeV; run sss2 -omp N. Material number densities are the verified deck's values; ZAID .06c (600 K) assumed — set 'set acelib' to match. Spec-derived EXAMPLE TRANSLATION — NOT benchmark-validated. Now AXIALLY COMPLETE: full ~25-layer axial build per pin (active fuel z 36.748-402.508 cm segmented by 8 Inconel grid spacers; plenum/spring, SS top nozzle, support plates, guide-tube dashpot, Pyrex BA + plenum stacks, end plugs) ported from the verified SCONE deck. Now also RADIALLY COMPLETE: per-assembly Pyrex BA clusters (real 6/12/15/16/20-rod patterns), the stepped SS304 baffle/former, the four octant neutron-shield pads, downcomer water and RPV rings all ported from the verified SCONE core; no radial simplifications remain. Sep 2026: lattice maps are now written bottom row first (Serpent reads the first Nx entries as the minimum-y row, the opposite of SCONE/OpenMC), which the earlier revision had upside down, and every 17x17 map carries a ring of water pins so the 0.043 cm strip between the pin array and the 21.50364 cm assembly pitch is defined; verified point-for-point against the SCONE deck with OWEN Compare Geometry (100 % boundary agreement). Supply your own cross sections and converge before drawing physics conclusions. Not an official MIT/CRPG product. Source: serpent-examples/beavrs_fullcore.sss.
by @caalh·10 days ago - mcnpPWR
MCNP — BEAVRS Cycle 1 Full-Core PWR (spec-derived translation)
MCNP translation of the author-verified SCONE BEAVRS full core: a nested core lattice (21.50364 cm assembly pitch) of 17×17 assembly lattices (1.26 cm pin pitch) on the real 193-assembly loading map (1.6/2.4/3.1 wt% UO2), with 24 guide tubes + central instrument tube, Pyrex burnable-poison rods, control rods withdrawn, and the core barrel/RPV shells. Material number densities are the verified deck's values; ZAID .80c (ENDF/B-VII.1) assumed though the verified data was JEF-3.1.1 at 600 K (cross-library k-eff bias expected). Spec-derived EXAMPLE TRANSLATION — NOT benchmark-validated. Now AXIALLY COMPLETE: full ~25-layer axial build per pin (active fuel z 36.748-402.508 cm segmented by 8 Inconel grid spacers; plenum/spring, SS top nozzle, support plates, guide-tube dashpot, Pyrex BA + plenum stacks, end plugs) ported from the verified SCONE deck. Now also RADIALLY COMPLETE: per-assembly Pyrex BA clusters (real 6/12/15/16/20-rod patterns), the stepped SS304 baffle/former, the four octant neutron-shield pads, downcomer water and RPV rings all ported from the verified SCONE core; no radial simplifications remain. Sep 2026: lattice cells now list the +x/+y planes first (MCNP places element (1,0,0) beyond the FIRST listed surface, manual 5.5.5), which the earlier revision got backwards and so read every fill map rotated 180 degrees — baffle plates on the wrong faces, asymmetric BA patterns flipped; verified point-for-point against the SCONE deck with OWEN Compare Geometry (100 % boundary agreement) and card images kept to 80 columns. Supply your own ACE data and converge before drawing physics conclusions. Not an official MIT/CRPG product. Source: mcnp-examples/beavrs_fullcore.i.
by @caalh·10 days ago - mcnpPWR
MCNP — 17×17 PWR Assembly (baseline)
Heterogeneous 17×17 Westinghouse-style PWR assembly in MCNP6 built from two universes (fuel pin + guide-tube water column) tiled onto a 17×17 square lattice with the standard 24 guide-tube positions, surrounded by a water reflector. Energy-binned F4 track-length flux in a representative pin plus an FMESH14 17×17 pin-power mesh tally for assembly-power distribution. Source: src/pages/mcnp/example-assembly.tsx (audited March 2026).
by @caalh·3 months ago - mcnpPWR
MCNP — 3×3 Pin-Lattice Criticality (baseline)
Compact 3×3 fuel-pin array criticality benchmark in MCNP6. 5% enriched UO2 pins with Zircaloy clad and water moderator on a 1.26 cm pitch, reflective outer boundary (`*` prefix on the boundary surfaces). `kcode 5000 1.0 50 300` with 5 `ksrc` seeds in the central pin. Small, fast, and useful for testing tally setups before moving to a full assembly. Source: src/pages/mcnp/example-criticality.tsx (audited March 2026).
by @caalh·3 months ago - sconePWR
SCONE — 5×5 PWR Assembly (baseline)
5×5 PWR-style assembly in SCONE using `latUniverse` of three pin types: 21 fuel pins (`pinUniverse 31000`), 3 guide-tube positions (`12000`), and 1 central instrument tube (`14000`). Eigenvalue calculation with a 32×32 `fissionRate` map for pin-power distribution. Materials sized for testLib (ZAID `.03`) so it runs without a production ACE library. Source: scone-examples/verify/tutorial_assembly_5x5_testlib (in the `run_all.ps1` harness — verified).
by @caalh·3 months ago - mcnpShielding
MCNP — Neutron Shielding (baseline)
Fixed-source neutron shielding analysis in MCNP6: 14 MeV point source (`sdef par=n erg=14`) collimated through a steel slab, then a concrete slab (NBS ordinary), with two point detectors (F5) and surface/cell flux tallies (F2/F4) downstream. Demonstrates importance biasing (`imp:n=1→2→4→2→0`) and 7-group MeV energy binning for shielding work. Source: src/pages/mcnp/example-shielding.tsx (audited March 2026).
by @caalh·3 months ago - sconeShielding
SCONE — Fixed-Source Shielding Slab (baseline)
1-D-style fixed-source neutron shielding stack in SCONE: 1 MeV `pointSource` at x=2.5 cm, three water cells (source / shield / detector regions) along x, with a `collisionClerk` flux tally on a 50-bin x-axis `spaceMap`. Uses water as a testLib-safe stand-in for Air/Concrete; the production variant (`tutorial_shielding_slab_production`) keeps the same geometry but swaps in Air + Concrete materials and a full ACE library. Source: scone-examples/verify/tutorial_shielding_slab (in the `run_all.ps1` harness — verified).
by @caalh·3 months ago - sconeTest reactor
SCONE — Bare Critical Cylinder (baseline)
Minimal SCONE input for a bare critical assembly (cylindrical stand-in — SCONE has no native sphere surface). One fuel material inside a zCylinder; water reflector outside; vacuum outer boundary. Useful as the smallest possible SCONE eigenvalue calculation. Source: scone-examples/verify/tutorial_bare_sphere_clean.
by @caalh·3 months ago - openmcPWR
OpenMC — 17×17 PWR Assembly (baseline)
Full 17×17 PWR assembly in OpenMC 0.15.x with fuel pins, guide tubes, and a central instrumentation tube on a 1.26 cm pitch. Tallies: assembly-averaged flux/fission/absorption, a 17×17 pin power mesh tally, and an energy-resolved fuel spectrum. Source: openmc-examples/example_assembly/build_model.py — matches ReactorMC /openmc/example-assembly/.
by @caalh·3 months ago - sconePWR
SCONE — BEAVRS Cycle 1 PWR (baseline benchmark)
MIT BEAVRS Rev 2.0 — Westinghouse 4-loop PWR, 193 assemblies, 17×17 lattice; enrichments 1.6/2.4/3.1% UO2; 975 ppm boron; HFP at 600 K; control rods withdrawn. This deck is the cleaned/sectioned twin of the author-verified `Scone Input` at the repo root and is exercised by `npm run verify:beavrs-parity`. Author-verified at Cambridge with JEFF-3.1.1 @ 600 K; additionally re-run independently against a downloaded ENDF/B-VIII.0 (Lib80x) ACE library, giving k-eff = 0.98906 ± 0.00019 (stable across 10k and 30k populations). Numerics and topology match the author-verified deck; comments and formatting cleaned up for maintenance.
by @caalh·3 months ago - serpentPWR
Serpent — PWR Pin Cell (baseline)
Serpent 2 PWR pin cell k-infinity calculation. UO2 fuel, helium gap, Zircaloy-4 cladding (simplified to dominant isotopes), and light-water moderator with H-in-H2O thermal scattering. 1.26 cm pitch with reflective boundaries (`set bc 2`). Run with `sss2 -omp N pin_cell.inp`. Source: ReactorMC tutorial /serpent/example-pin.
by @caalh·3 months ago - sconePWR
SCONE — PWR Pin Cell (baseline)
SCONE eigenvalue pin cell at testLib temperature/ZAID (`.03`). Demonstrates the canonical SCONE input layout: top-level physicsPackage settings, geometry with surfaces + pinUniverse, and nuclearData materials. Drop-in runnable against `scone-examples/verify/tutorial_fuel_pin_testlib`. To run with a production ACE library, change the ZAID suffix to `.06` and replace `$SCONE_ACE` with your library path — see the SCONE Simple Examples page on ReactorMC for the production variant.
by @caalh·3 months ago - mcnpPWR
MCNP — PWR Pin Cell (baseline)
Westinghouse 17×17-style PWR fuel pin in MCNP6: UO2 fuel (4% enriched), helium gap, Zircaloy-4 clad, light-water moderator, reflective outer boundary. Uses ENDF/B-VII.1 cross sections (.70c) and an S(α,β) thermal scattering kernel for H-in-H2O. Tallies an energy-binned track-length flux (F4) and fission energy deposition (F7) in the fuel cell. Source: ReactorMC tutorial /mcnp/example-pin.
by @caalh·3 months ago - openmcPWR
OpenMC — PWR Pin Cell (baseline)
Standalone Python script that builds the same PWR pin cell as the MCNP/Serpent baseline templates, using OpenMC 0.15.x. Materials, geometry, settings, and tallies (fuel flux, ν-fission, absorption) all in one file. Requires `OPENMC_CROSS_SECTIONS` to point at a valid cross_sections.xml. Source: openmc-examples/example_pin/build_model.py — kept in sync with ReactorMC /openmc/example-pin/.
by @caalh·3 months ago