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OWEN 0.3.8 — high-fidelity MCNP<->OpenMC converter (beta)

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@caalh caalh released this 03 Jul 02:27
v0.3.8
fc2cbd2

MCNP <-> OpenMC converter rewritten — graduates to beta

Both directions rewritten from scratch and validated against the bundled BEAVRS full core in real OpenMC (0.15.3). Serpent/SCONE targets remain experimental.

MCNP -> OpenMC

  • Full boolean region AST: intersections, unions, #cell / #() complements, nested parentheses
  • All common surfaces: planes (incl. three-point), spheres, cylinders, cones (one/two-sided), tori, GQ/SQ -> openmc.Quadric, and macrobodies RPP/RCC/BOX/RHP -> openmc.model composites
  • Multi-level universes; lat=1 -> RectLattice and lat=2 -> HexLattice (fill arrays with nR repeats, 3D arrays, self-fill, outer= heuristic)
  • trcl=/fill transforms -> translation/rotation; tmp= -> cell temperature
  • Graveyard (imp:n=0) elimination -> boundary_type='vacuum'; */+ surfaces -> reflective/periodic
  • Materials split per cell density, add_element for natural ZAIDs, official OpenMC S(a,b) names, metastable ZAIDs
  • kcode/multi-point ksrc -> Settings/IndependentSource; FMESH + F4/F6/F7 tallies

OpenMC -> MCNP

  • New architecture: static parser for flat scripts + a pure-Python trace harness (no OpenMC install needed) for procedural scripts (loops/functions, e.g. native BEAVRS) -> JSON IR -> MCNP emitter
  • De Morgan region normalization, synthesized lattice windows + graveyard, S(a,b) -> mt, temperatures -> tmp=

Validation (BEAVRS gauntlet)

  • Forward: converted full core loads in OpenMC — 327 cells / 62 universes / 16 lattices / 13 materials; 4000-point material sampling vs the native deck: 0 mismatches; transport smoke test runs
  • Reverse: native procedural BEAVRS script traced -> MCNP; extractor instance parity +0.004%, validator zero Errors
  • Round-trips (pin cell, 17x17 assembly) preserve materials, S(a,b), lattices, settings
  • 52 new converter tests; suite total 483

Fixed

  • beavrs_fullcore_mcnp.i: root cells 300/303-307 illegally reused pin-cell ids — renumbered 343-348

Known gaps (TODO-marked, never silently dropped)

  • Tallies beyond FMESH type-4 and F4/F6/F7; sdef beyond point sources; surface TR transforms flagged but not applied
Assets 3
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